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2.1 Limits Imposed on SRP Section II Acceptance Criteria by ABWR Standard Plant The information in this section of the reference ABWR DCD, including all tables, is incorporated by reference with the following site-specific supplements in Table 2.1-1.
United States Nuclear Regulatory Commission Official Hearing Exhibit In the Matter of: NUCLEAR INNOVATION NORTH AMERICA LLC (South Texas Project Units 3 and 4) Commission Mandatory Hearing Docket #: 05200012 & 05200013 Exhibit #: NRC-006C-MA-CM01 Identified: 11/19/2015 Admitted: 11/19/2015 Withdrawn: Rejected: Stricken: Other:
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Table 2.1-1 Limits Imposed on SRP Section II Acceptance Criteria by ABWR Design
The supplementary information, provided in the column marked "Discussion," consists of a statement as to whether the SRP limits specified for the reference ABWR design are met for the STP 3 & 4 site, and a roadmap to the FSAR sections where further discussion is provided.
SRP Section Subject Limits Discussion Geography and Demography 2.1.1 Site Location and None N/A Description 2.1.2 Exclusion Area None N/A Authority and Control 2.1.3 Population None N/A Distribution Nearby Industrial, Transportation and Military Facilities 2.2.1- Identification of Identify potential hazards in the site The potential external hazards 2.2.2 Potential Hazards vicinity that have a probability of in the vicinity of the STP site are in Site Vicinity occurrence >10-7 per year which identified in Subsections 2.2S.1 produce: and 2.2S.2. The only potential (1) missiles more energetic than the external hazard identified with a tornado missile spectra, or frequency near 1 x 10-7 was an (2) pressure effects in excess of the aircraft accident with a design basis tornado. conservatively calculated total impact frequency of 1.09 x 10-7. 2.2.3 Evaluation of Evaluate only those potential An evaluation of the aircraft Potential Accidents hazards identified above. hazards that could impact the STP site is provided in Subsection 2.2S.2.7.2. Although no other external hazards approach a frequency of 1 x 10- 7, other potential external hazards in the vicinity of the STP site are discussed in Subsection 2.2S.3.
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Table 2.1-1 Limits Imposed on SRP Section II Acceptance Criteria by ABWR Design SRP Section Subject Limits Discussion Meteorology 2.3.1 Regional Per Table 2.0-1. The ABWR site parameters Climatology specified in Table 2.0-1 envelop the STP site-specific characteristics related to regional climatology, with the following exceptions, maximum rainfall rate and ambient design temperatures relative to three of the wet-bulb exceedance values. These departures are discussed in Table 2.0-2 (see also STP DEP T1 5.0-1).
Further details on regional climatology are provided in Subsection 2.3S.1. 2.3.2 Local Meteorology None N/A 2.3.3 Onsite None N/A Meteorological Measurements Program 2.3.4 Short-Term Show that the site meteorological The design basis accident Diffusion dispersion values as calculated in doses calculated based on the Estimates for accordance with Regulatory Guide STP site meteorological Accidental 1.145, and compared to dose dispersion values are Atmospheric values given in Chapter 15, result in discussed in Subsections 15.2, Releases doses less than stipulated in 10 15.56, and 15.7. The calculated CFR 100 and the applicable doses meet the dose limits portions of SRP Sections 11 and specified in 10 CFR 100. 15. 2.3.5 Long-Term None N/A Diffusion Estimates Hydrology Engineering 2.4.1 Hydraulic Per Table 2.0-1. The ABWR site parameters Description specified in Table 2.0-1 envelop the STP site-specific characteristics related to hydrology. Further details are provided in Subsection 2.4S.1.
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Table 2.1-1 Limits Imposed on SRP Section II Acceptance Criteria by ABWR Design (Continued) SRP Section Subject Limits Discussion 2.4.2 Floods Per Table 2.0-1. The maximum flood level for the STP site is discussed in Subsections 2.4S.2 and 2.4S.4 (see also Table 2.0-2 and STP DEP T1 5.0-1). Site-specific flood protection measures are described in Subsection 3.4.1.1.1. 2.4.3 Probable None N/A Maximum Flood on Streams and Rivers 2.4.4 Potential Dam Demonstrate that failure of existing Failure of the Main Cooling Failures and potential upstream or Reservoir (MCR) would result in Seismically downstream water control the worst case flood level, and Induced structures will not exceed flooding exceeds the SRP limit for the 30.5 cm below grade. reference ABWR design as discussed in Subsection 2.4S.4 see also Table 2.0-2 and STP DEP T1 5.0-1). Site-specific flood protection measures are described in Subsection 3.4.1.1.1. 2.4.5 Probable Probable maximum surge and The probable maximum surge Maximum Surge seiche flooding level 30.5 cm below flooding level is within the SRP and Seiche grade. limit for the reference ABWR Flooding design. Flooding due to seiche effects is considered insignificant at the STP site. See Subsection 2.4S.5 for further details. 2.4.6 Probable Probable maximum tsunami The probable maximum tsunami Maximum Tsunami flooding level 30.5 cm below grade. flooding level for the STP site is within the SRP limit for the reference ABWR design as discussed in Subsection 2.4S.6. 2.4.7 Ice Effects None N/A 2.4.8 Cooling Water None N/A Channels and Reservoirs 2.4.9 Channel Diversion None N/A
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Table 2.1-1 Limits Imposed on SRP Section II Acceptance Criteria by ABWR Design (Continued) SRP Section Subject Limits Discussion 2.4.10 Flooding None N/A Protection Requirements 2.4.11 Cooling Water None N/A Supply 2.4.12 Groundwater Per Table 2.0-1. The groundwater depth in the power block areas for STP 3 & 4 is below the maximum groundwater level of 61 cm (2 ft) below grade as specified in Table 2.0-1. Further information is provided in FSAR Subsection 2.4S.12. 2.4.13 Accidental None N/A Releases of Liquid Effluent in Ground and Surface Waters 2.4.14 Technical None N/A Specifications and Emergency Operation Requirement
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Table 2.1-1 Limits Imposed on SRP Section II Acceptance Criteria by ABWR Design (Continued) SRP Section Subject Limits Discussion Geology, Seismology and Geotechnical Engineering 2.5.1 Basic Geology and None N/A Seismic Information 2.5.2 Vibratory Ground Per Table 2.0-1. The ABWR DCD design Motion parameters specified in Table 2.0-1 related to seismology are enveloped for the STP site. Further details are provided in Subsection 2.5S.2. 2.5.3 Surface Faulting No faulting at or near the ground There is no potential for surface surface is accepted. faulting through the STP 3 & 4 site footprint as discussed in Subsection 2.5S.3. 2.5.4 Stability of Per Table 2.0-1. The ABWR site parameters Subsurface specified in Table 2.0-1 envelop Materials and the STP site-specific Foundations characteristics related to stability of subsurface materials and foundations. Further details are provided in Subsection 2.5S.4. 2.5.5 Surface of Slopes None N/A
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1.1 Introduction The information in this section of the reference ABWR DCD, including all subsections and figures, as modified by the STP Nuclear Operating Company Application to Amend the Design Certification rule for the U.S. Advanced Boiling Water Reactor (ABWR), "ABWR STP Aircraft Impact Assessment (AIA) Amendment Revision 3," dated September 23, 2010 is incorporated by reference with departures and supplements.
STD DEP 1.1-1
STP DEP 1.1-2
STP DEP 10.1-3 (Figure 1.1-2)
STD DEP Vendor
1.1.1 Format and Content The information in this subsection of the reference ABWR DCD is incorporated by reference with the following site-specific supplement.
The STP Combined License Application (COLA), Part 2, Final Safety Analysis Report (FSAR) incorporates the ABWR DCD, as applicable, by reference, without repeating the information from the DCD. The reference ABWR DCD refers to U.S. ABWR Design Control Document, GE Nuclear Energy, Revision 4 dated March 1997, as approved in 10 CFR Part 52, Appendix A, and as modified by the STP Nuclear Operating Company Application to Amend the Design Certification Rule for the U.S. Advanced Boiling Water Reactor (ABWR), "ABWR STP Aircraft Impact Assessment (AIA) Amendment Revision 3," dated September 23, 2010.
The FSAR, as required by the ABWR design certification rule (10 CFR 52, Appendix A, Section IV.A.2.a), maintains the ABWR DCD organization and numbering system.
In some cases, new sections have been added to accommodate Regulatory Guide (RG) 1.206 guidance. In general, those new sections are designated with an “S”. For example, ABWR DCD Tier 2, Section 1.9 is entitled “COL License Information.” However, Regulatory Guide 1.206, Section 1.9 is entitled “Conformance with Regulatory Criteria.” Therefore, STP Nuclear Operating Company (STPNOC) has incorporated by reference Tier 2, Section 1.9 and has added a new Section 1.9S entitled “Conformance with Regulatory Criteria.”
There are two exceptions to the “S” section format convention.
The individual Chapter 18 sections in Regulatory Guide 1.206 have different titles than the reference ABWR DCD, so they would be candidates for having the “S” designator. However, Regulatory Guide 1.206 requests the description of a Human Factors Engineering (HFE) process consisting of 12 program review elements. The guidance for describing an HFE process at the time the ABWR was certified consisted of eight elements, as described in Appendix 18E and other sections of
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the FSAR. The approved, and largely equivalent, HFE process information from the ABWR DCD is incorporated by reference.
DG-1145 identified six new sections in Chapter 19 and STPNOC developed six “S” sections to meet those requirements. Regulatory Guide 1.206 identifies only three sections, but they have different content requirements than DG-1145. STPNOC will incorporate the reference ABWR DCD Chapter 19 sections by reference and supplement that information with one “S” section that provides a roadmap to the location of the information requested by Regulatory Guide 1.206.
The information in each section of the FSAR (or subsection, based on section length and complexity) is presented in the order of text first, tables second, and figures third. Text pages are oriented in portrait with tables and figures in portrait or landscape. Figure pages may be as large as 11” x 17”. Page numbering uses the section number followed by a hyphen and sequential numbering for the page in that section (e.g., the fourth page in section 3.2 is numbered as 3.2-4).
There are primarily two types of new information in the FSAR:
Departures from the information in the DCD; and
Supplements to the information in the DCD (including information to address COL License Information Items; information to replace conceptual design information in the DCD; information on siting and site-specific systems, organizations, and programs; and information requested by Regulatory Guide 1.206 that pertains to issues not addressed in the DCD).
The STP 3 & 4 COLA is the reference-COLA (R-COLA) for the ABWR standard design. Departures and supplements are designated as either:
“standard,” meaning that the information is suitable for use in subsequent COLAs (S-COLAs), e.g., STD DEP 6.2-1; and
“site-specific,” meaning that the information is applicable only to STP 3 & 4, e.g., STP DEP 6.2-1.
Each departure is designated with a unique number. For example, STD DEP 17.6-2 is a standard departure in section 17.6 and is the second departure in that section. If departures are in Tier 1, the designation “T1” is added, e.g. STD DEP T1 3.6-1. Site- specific departures begin with “STP” instead of “STD”. Departures are numbered based on the primary section that describes the system containing the departure. Because departures can affect many sections, the single departure number is used in all sections affected by the departure. There is a category of administrative departures that correct non-technical errors in the DCD, such as incorrect figure references or typographical errors in equations. These are designated as STD DEP Admin.
In situations where it is necessary to provide both reference ABWR DCD and FSAR information within a paragraph (e.g., for departures from the DCD), the text is presented as follows. Italicized text is used for ABWR DCD information printed in the
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FSAR. Deleted ABWR DCD information is identified with italicized strikethrough (e.g., strikethrough) text.Arial underlined unitalicized text is used for new information.
To the maximum extent practical, the FSAR uses the table and figure numbering directly from the reference ABWR DCD. Tables and figures use the same numbering sequence. Tables and figures associated with a #.# section number are numbered in a #.# -# format, and are numbered in the order in which they are addressed in the section (e.g., the third figure discussed in Section 15.4 is numbered “Figure 15.4-3.”) To indicate ABWR DCD vs. combined license application (COLA) information within a table or figure, an Arial font is used for ABWR DCD information that is retained and a bold Arial font is used for new information. Deleted reference ABWR DCD information in a table or figure is identified by a strikethrough (e.g., strikethrough). Revisions to figures are highlighted with bubbles. If a bubble contains information, the contents have been added or revised, if the bubble is empty, previous content has been deleted.
Proprietary and security sensitive information contained within the FSAR is presented in accordance with the guidance provided in COLA Part 1, Introduction.
Acronyms are used in the FSAR text, tables, and figures to reference frequently used or repeated systems, components, or parameters. Each acronym is defined the first time it is used in a section (X.Y).
The term “incorporated by reference” (IBR) means the words that are incorporated by reference from the ABWR DCD are considered to be part of the COLA as though each word had been retyped into the COLA. A descriptive phrase is used each time the term “incorporated by reference” is used to explain the specific situation. For example,
“Incorporated by reference with no departures or supplements” specifically indicates that there are no changes whatsoever to the reference ABWR DCD information incorporated by reference.
“Incorporated by reference with the following departure” indicates that a certain departure from the reference ABWR DCD verbiage is taken.
“Incorporated by reference with the following supplement” indicates that the ABWR DCD words are included in their entirety, but additional information is also included. Supplements are designated as site-specific or standard, but are not numbered.
“Incorporated by reference with the following departures and supplements” indicates that both departures (which are numbered) are taken and supplemental information is added.
Some sections may include both departures and supplements; other sections may include only departures or supplements. The introductory language for each section indicates which case applies.
The FSAR incorporates by reference information from the reference ABWR DCD at the “X.Y” section level. This incorporation by reference includes all lower level subsections
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within the DCD (e.g., “X.Y.Z” subsections) and all tables and figures associated with the sections, unless otherwise specified.
In general, when a departure affects relatively few paragraphs within a section, only those paragraphs are reproduced within the FSAR identifying the changes in the text of the reference ABWR DCD. In a few cases, sections (e.g., 9.1 and 6C) have enough departures that they are reproduced entirely in italics with strikeouts and underlining to indicate the changes. In other cases, the DCD text within a section is deleted in its entirety and replaced with completely new text. These cases are explained at the beginning of the respective sections.
The reference ABWR DCD contains some information termed “conceptual,” indicating that the design was not finalized and was not approved by the NRC. The STP 3 & 4 COLA addresses this conceptual information with supplemental design information. The replacement of conceptual design information with supplemental design information is considered a supplement.
COL License Information Items are addressed in the COL License Information summary subsections which occur at the end of each FSAR section. In a few cases there are COL License Information Items that are not summarized at the end of DCD sections. In these cases, the COLA addresses them as supplements as part of the subsection in which they are located. The information that addresses the COL License Information Items is a supplement.
When the FSAR refers to Section X.Y, Appendix XA, Figure X.Y-1, or Table X.Y-2, the reference is to the associated section, appendix, figure, or table in this FSAR. If there is a reference to a section, appendix, figure, or table in the reference ABWR DCD, the FSAR specifically refers to the DCD, e.g., “DCD Section X.Y”. If there is a reference to a section in another part of the COLA, the COLA Part number or title will precede the section referral, e.g., “Environmental Report Section X.Y”.
Regulatory Guide 1.206 requests a supplemental list of acronyms for items not included in the referenced certified design. Acronyms are defined the first time they are used in each section (X.Y) of the FSAR, so a list of definitions is unnecessary. There is a list of standard acronyms that are universally understood in this application and do not require definition the first time they are used in a section. That list of standard acronyms is limited to ABWR, DCD, DOE, GE, LWR,NINA, NRC, STP, STPNOC, U.S., and USA.In Part 1 of the COLA and Part 2, Tier 2, Chapters 1, 13 and 17, the acronym “STPNOC” means STP Nuclear Operating Company. Otherwise, “STPNOC” means the lead applicant or lead licensee responsible for either design and construction (i.e., NINA) or operations (i.e., STPNOC) depending upon the applicable time period or historical context. As such, unless referring to a historical action that occurred prior to January 24, 2011, “STPNOC” means NINA until the date on which the Commission makes a finding that acceptance criteria are met under 10 CFR 52.103(g) or allows operation during an interim period under the combined license under 10 CFR 52.103(c). Thereafter, it means STPNOC.
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The ABWR DCD has references to the ABWR Standard Safety Analysis Report (SSAR).
These DCD references to the SSAR can be divided into seven categories:
(1) Proprietary information that must be included in the plant-specific DCD in accordance with Section IV.A.3 of Appendix A to Part 52 of the ABWR Design Certification Rule. This information, referenced in Tier 2, Sections 3B, 4.3, 4A, 4B, 4D, 6.3, and 18H, is contained in COLA Part 10.
(2) Proprietary information not included in the DCD, but referenced in the SSAR as being submitted under separate cover. This information, referenced in Tier 2, Section 1.3, is possessed by a STPNOC contractor and is available under contract for possession and use by STPNOC.
(3) Safeguards information that must be included in the plant-specific DCD in accordance with Section IV.A.3 of Appendix A to Part 52 of the ABWR Design Certification Rule. This information, referenced in Tier 2, Section 13 is contained in COLA Part 8, or is possessed by a STPNOC contractor and is available under contract for possession and use by STPNOC.
(4) Detailed PRA information. This information, referenced in Tier 2, Sections 15D and 19, is specifically not incorporated into the DCD in accordance with 10 CFR 52, Appendix A, Section IIIB.
(5) Proprietary information not included in the DCD that has been fully incorporated into the COLA and is no longer proprietary. This information, referenced in Tier 2, Section 11A has been fully incorporated into FSAR Sections 11.2 and 11.4.
(6) Tier 2 references that consist of historical responses by GE Nuclear Energy to NRC requests for additional information associated with preparation of the DCD. This information, referenced in Tier 2, Section 20, has been retained and is interpreted as a reference to Tier 2 of the DCD, as stated in Section 20.0, “Question and Response Guide.”
(7) Use of the term SSAR to reference sections or subsections that are identical to the corresponding DCD sections or subsections. This information, referenced in Tier 2, Sections 3.13, 7.7, 8.3 and 9A has been verified to be identical to the information contained in the SSAR.
Table 1.1-1 provides a breakdown of the Tier 2 references to the SSAR and how they have been resolved.
1.1.4 Design Process The following supplement addresses COL License Information Item 1.1.
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The project design process is fully described in the STP 3 & 4 Quality Assurance Program Description submitted under separate cover and referenced in FSAR Section 17.5S.
1.1.5 Type of License Required STD DEP 1.1-1
This subsection of the reference ABWR DCD is replaced in its entirety by the following site-specific departure.
The STP 3 & 4 FSAR is submitted in support of the application for a Class 103 Combined License under 10 CFR 52.
The following site-specific supplement is added to this subsection.
The anticipated completion dates (fuel load) for STP 3 & 4 are September 2017 and October 2018, respectively, with anticipated commercial operation dates as early as June 2018 and July 2019, respectively.
1.1.6 Number of Plant Units STP DEP 1.1-2
This subsection of the reference ABWR DCD is replaced in its entirety by the following site-specific departure.
STP 3 & 4 is a two unit facility.
1.1.7 Description of Location The information in this subsection of the reference ABWR DCD is incorporated by reference with the following site-specific supplement.
The STP 3 & 4 site is located in south-central Matagorda County, Texas; west of the Colorado River, 8 miles north-northwest of the town of Matagorda; and approximately 89 miles southwest of Houston as shown on Figure 1.1-3. The facility is co-located with STP 1 & 2, two existing pressurized water reactors, as shown in Figure 1.1-4.
1.1.8 Type of Nuclear Steam Supply STD DEP Vendor
This plant will have a boiling water reactor (BWR) nuclear steam supply system (NSSS) designed and supplied by GE and designated as ABWR.
1.1.11.1 Design Process to Establish Detailed Design Documentation The following site-specific supplemental information addresses COL License Information Item 1.1.
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The design process utilized to establish the STP 3 & 4 detailed design documentation is described in Subsection 1.1.4.
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Table 1.1-1 DCD References to the SSAR Section Item Resolution 1.3 Table 1.3-1 Footnote 3 Proprietary information is possessed by a STPNOC contractor and is available under contract for possession and use by STPNOC. 3.13 3.13.3 General ABWR Containment Structures, DCD identical to the SSAR Systems and Barrier Descriptions 3B Tables 3B-2, 3, 4, 5, 6, 7, 8, 9 and Figures 3B-2, 3, 8, Incorporated into COLA Part 10 9, 10, 14, 15, 16, 17, 18, 19, 20, 22, 23, 24, 25, 27, 29, 31, 32, 33, and 34 4.3 Figure 4.3-2 Incorporated into COLA Part 10 4A Figures 4A-1a, 4A-1d, 4A-1e, 4A-2a, 4A-2d, 4A- 2e, Incorporated into COLA Part 10 4A-3a, 4A-3d, 4A-3e, 4A-4a, 4A-4d, 4A-4e, 4A-5a, 4A-5d, 4A-5e, 4A-6a, 4A-6d, 4A-6e, 4A- 7a, 4A-7d, 4A-7e,4A-8a, 4A-8d, 4A-8e, 4A-9a, 4A-9d, 4A-9e, 4A- 10a,4A-10d, 4A-10e, 4A-11a, 4A-11d, 4A-11e, 4A- 12a, 4A-12d,4A-12e, 4A- 13a, 4A-13d, and 4A-13e. 4B 4B.2 References Incorporated into COLA Part 10 4D Reference Fuel Design Compliance with Acceptance Incorporated into COLA Part 10 Criteria 6.3 Table 6.3-6 and Figures 6.3-10 through 6.3-79 Incorporated into COLA Part 10 7.7 7.7.2.11 Other Non-Safety-Related Control Systems DCD identical to SSAR 7.7 Figure 7.7-3, Sheet 71 of 87 DCD identical to SSAR with exception of interim drawing identification information 8.3 8.3.5 References DCD identical to SSAR 9A 9A.4.2.4.1 Control Room Complex DCD identical to SSAR 9A 9A.4.2.6.1 Control Room HVAC Supply “B” (Rm No. DCD identical to SSAR 621) 9A Table 9A.6-2 DCD identical to SSAR 9A Table 9A.6-4 Reference to the SSAR removed in COLA 11A 11A.2 Liquid Waste Management Proprietary information incorporated into COLA and made non-proprietary 11A 11A.4 Solid Waste Management System Proprietary information incorporated into COLA and made non-proprietary
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Table 1.1-1 DCD References to the SSAR (Continued) Section Item Resolution 13.6 13.6.2 Security Plan Safeguards Information is possessed by a STPNOC contractor and is available under contract for possession and use by STPNOC. 13.6 13.6.3 COL License Information Incorporated into COLA Part 8 15D Table 15D-1 Logic Equations PRA information referenced in the SSAR is not incorporated in the DCD as stated in Part 52, Appendix A, Section III.B. 15D Figures 15D-2 through 15D-5 PRA information referenced in the SSAR is not incorporated in the DCD as stated in Part 52, Appendix A, Section III.B. 18H Tables 18H-1 through 18H-14 Incorporated into COLA Part 10 19 Various PRA information referenced in the SSAR is not incorporated in the DCD as stated in Part 52, Appendix A, Section III.B. 20 20.0 Question and Response Guide As provided in DCD Tier 2 Chapter 20, "Each Tier 2 reference to the SSAR in this chapter shall be interpreted as a reference to Tier 2 of the DCD."
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Figure 1.1-2 Heat Balance at Rated Power
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Figure 1.1-3 Surrounding Area Map
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Figure 1.1-4 10-Mile Radius Map
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1.2 General Plant Description The information in this section of the reference ABWR DCD, including all subsections, tables, and figures, as modified by the STP Nuclear Operating Company Application to Amend the Design Certification rule for the U.S. Advanced Boiling Water Reactor (ABWR), "ABWR STP Aircraft Impact Assessment (AIA) Amendment Revision 3," dated September 23, 2010 is incorporated by reference with the following departures and supplements.
STD DEP T1 2.3-1
STD DEP T1 2.4-3
STP DEP T1 2.5-1
STD DEP T1 2.14-1 (Figures 1.2-2 and 1.2-8)
STD DEP T1 3.4-1
STP DEP 1.1-2 (Figure 1.2-1)
STD DEP 1.2-1
STP DEP 1.2-2 (Figures 1.2-24 through 1.2-37)
STD DEP 3.8-1 (Figures 1.2-23a through 1.2-23e)
STD DEP 8.3-1
STD DEP 9.1-1
STP DEP 9.4-3
STD DEP 9.4-4
STP DEP 10.2-1
STP DEP 10.4-2
STD DEP 10.4-6
STD DEP 11.4-1
STD DEP Admin
1.2.1.3 Plant Design and Aging Management The following site-specific supplement addresses COL License Information Item 1.1a.
Because the design life for the ABWR is 60 years (40 years for the initial license condition plus anticipated renewal requests), steps are initiated in the design process to aid in the application, selection and procurement of components with optimum
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design life characteristics, and to maintain the plant's original design basis throughout its life.
Design Life To achieve design life objectives, the following general design considerations are incorporated into design processes and practices:
Design margins: Adequate margins are included in the original design to prevent unplanned reanalysis and possible modifications when deviation from the design value occurs during the equipment manufacture or construction.
Water quality: The water quality requirements are used in the material selection and design of the water treatment systems, water storage systems, and associated water containing systems. The operating limits contained in the water quality requirements are provided to help prevent corrosion and cracking of reactor internals and to reduce the corrosion products produced from water containing systems. These requirements are specified in the procurement documents.
Materials: Materials and process requirements are specified in procurement documents to prevent intergranular stress corrosion cracking (IGSCC) of austenitic stainless steel in mechanical systems. In addition, materials and process requirements considering prior BWR experience are specified in hardware designs and component procurement documents to provide for required fracture toughness.
Corrosion design requirements: equipment design, material selection, and water chemistry are important to minimize both internal and external erosion and corrosion at the temperature, moisture content, and velocity of the fluids being processed. General corrosion allowance is used with additional margin in the design, and other corrosion mechanisms such as flow-accelerated corrosion are also considered.
Additional practices that are implemented to support a 60-Year ABWR Plant Design life include:
Condition monitoring provides data to trend SSC performance so that deterioration of structures or components may be detected before the loss of an intended design function. Condition monitoring also consists of visual or non-destructive testing inspections for structures and passive type components.
ABWR design features provide a high confidence that the cumulative plant and system transients will be kept well within the limits of occurrences as designed. ABWR plant operating events and dynamic loading events are summarized in Table 3.9-1 of the FSAR. The design requirements of the safety-related piping and equipment subjected to specific applicable thermal hydraulic transients derived from the system behavior during the events listed in this table are documented in design specifications and/or stress reports of the respective equipment.
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Instrument and Control (I&C) systems and components are designed to ensure system performance monitoring and system functions can be achieved. Sequencing of events recording capability enables plant personnel to evaluate the plant transients quickly. The transient recording and analyses allows retrieval of data for post-trip root cause analysis and to support system testing. Recording capabilities and installed instruments enables operators to monitor and trend significant transients over the design lifetime.
The environmental conditions applicable to safety-related mechanical and electrical equipment and qualification tests are described in Section 3.1 1 of FSAR. Environmental conditions for the areas where safety-related equipment are located are calculated for normal, abnormal, test, and post-accident conditions and are documented in Appendix 31 of FSAR.
System design documentation contains a system description and intended function, interfaces/boundaries, environment, and requirements that major components have to meet. The documentation also provides design life, environmental limits, acceptance criteria for condition indicators, the description of the material for system equipment and piping, and control equipment and devices. The locations of the equipment, piping and control devices, environmental and seismic conditions for these components are also included.
Equipment and component design life requirements are to be incorporated into equipment purchase specifications. The purchase specifications specify the component design life requirements, applicable expected transients in the design life, environmental conditions to which the equipment will be exposed during plant operation, and properties of the working fluid, to allow the equipment supplier to evaluate the design life of their supplied equipment.
Equipment suppliers are required to provide the recommended frequencies of replacement and/or maintenance activities for any component for which the design life is less than 60 years. These recommended replacement and maintenance activities are considered as inputs to develop the preventive maintenance program.
Design Life Maintenance Plant operational components and equipment, except the reactor vessel, are designed to be replaceable, design life not withstanding. Normal operational and maintenance practices and programs provide for monitoring, preventive and corrective refurbishment and repair, as appropriate, to assure that the design life of the plant is achieved.
The following programs provide the means for maintaining requirements and monitoring the performance or condition of SSCs against established goals to provide reasonable assurance: 1) that design life requirements and critical attributes of SSCs are documented and maintained, 2) that SSCs are capable of performing their intended function, and 3) that they are at acceptable levels of safety, thermal, and economic performance.
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Configuration Management Program
Records Management Program
Inservice Test and Inspection Program
Check Valve Program
Motor-Operated Valve Program
Air Operated Valve Program
Containment Leakage Test Program
Erosion/Corrosion Program
Environmental Qualification Program
Individual Plant Examination/Probabilistic Risk Assessment
Structural Monitoring Program
Maintenance Rule Program
Plant Performance Monitoring Program
Surveillance Test Program
Preventive Maintenance Program
Radioactive Effluent Monitoring Program
Chemistry Analysis
Fatigue Management Program
Flow Accelerated Corrosion Program
Aging Management Because the initial license term is for 40 years, an aging management plan which implements the provisions described in NUREG-1801, Generic Aging Lessons Learned (GALL) Report, will be initiated to support license renewal submittal.
Aging management covers containment structures, liner plates, embedded or buried structure components, piping and components. Aging management for long-lived passive structures and components includes information regarding the materials of construction, potential causes of corrosion, environment, aging effects requiring management, and aging management activities to monitor and to control aging effects.
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Aging management follows GALL established AMPS to monitor the long-lived passive components, or acceptable alternatives thereto. The time limited aging analysis (TLAA) programs described in GALL or alternatives will be monitored and trended to ensure the component or structure design limits are not exceeded. Because of ABWR design life is 60 years, the evaluation for time limited aging analyses (TLAA) programs as described in NUREG-1 801 is not required.
References EPRI Utility Requirement Document Section 1 1.3, Volume 11, Chapter 1, Design Life
NUREG-1801, Generic Aging Lessons Learned (GALL) Report
NUREG/CR-4731 and 5314, USNRC Nuclear Plant Aging Research (NPAR) Program
1.2.2.1.1 Site Location STD DEP Admin
The information in this subsection of the reference ABWR is incorporated by reference with the following site-specific supplement.
STP 3 & 4 are located on the existing South Texas Project (STP) site. The 12,220 acre site is located in a rural area of south central Matagorda county. STP 3 & 4 are located near the Main Cooling Reservoir which has sufficient capacity to serve as main condenser heat sink. The Colorado River provides makeup water to the Main Cooling Reservoir.
1.2.2.1.2.3 Geology and Seismology The information in this subsection of the reference ABWR is incorporated by reference with the following site-specific supplement.
The Ultimate Heat Sink and Reactor Service Water Piping Tunnel are designed to the site-specific SSE acceleration.
1.2.2.1.3 Site Arrangements STD DEP 1.2-2
The containment and building arrangements, including equipment locations, are shown in Figures 1.2-2 through 1.2-37. The arrangement of these structures on the plant site is shown in Figure 1.2-1.
1.2.2.2.2.1 Main Steamline Isolation Valves STD DEP T1 2.3-1
All pipelines that both penetrate the containment and offer a potential release path for radioactive material are provided with redundant isolation capabilities. Isolation valves are provided in each main steamline to isolate primary containment upon receiving an
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automatic or manual closure signal. Each is powered by both pneumatic pressure and spring force. These valves fulfill the following objectives: prevent excessive damage to the fuel barrier by limiting the loss of reactor coolant from the reactor vessel resulting from either a major leak from the steam piping outside the containment or a malfunction of the pressure control system resulting in excessive steam flow from the reactor vessel.
(1) Prevent excessive damage to the fuel barrier by limiting the loss of reactor coolant from the reactor vessel resulting from either a major leak from the steam piping outside the containment or a malfunction of the pressure control system resulting in excessive steam flow from the reactor vessel.
(2) Limit the release of radioactive materials by isolating the RCPB in case of the detection of high steamline radiation.
1.2.2.3.10 Steam Bypass and Pressure Control System STD DEP 10.4-6
A turbine bypass system is provided which passes steam directly to the main condenser under the control of the pressure regulator. Steam is bypassed to the condenser whenever the reactor steaming rate exceeds the load permitted to pass to the turbine generator. The turbine bypass system has the capability to shed 40% 33% of the turbine-generator rated load without reactor trip or operation of safety/relief valves. The pressure regulation system provides main turbine control valve and bypass valve flow demands so as to maintain a nearly constant reactor pressure during normal plant operation. It also provides demands to the recirculation system to adjust power level by changing reactor recirculation flow rate.
1.2.2.3.11 Process Plant Computer Functions (Includes PMCS, PGCS) STD DEP T1 3.4-1
Online plant computer functions process computers are provided to monitor and log process variables and make certain analytical computations. The performance and power generation control systems are included.
1.2.2.3.13 CRD Removal Machine Control Computer STD DEP 9.1-1
The CRD handling equipment local operation panel machine control computer provides automatic positioning, continuous operation and prevention of erroneous operation in the stepwise removal and installation of CRDs from the remote control room.
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1.2.2.4.3 Containment Atmospheric Monitoring System STD DEP T1 2.14-1
The Containment Atmospheric Monitoring System (CAMS) measures, records and alarms the radiation levels and the oxygen and hydrogen concentration levels in the primary containment under post-accident conditions. It is automatically put in service upon detection of LOCA conditions. Hydrogen and oxygen monitors are no longer required to mitigate design basis accidents.
1.2.2.5.3 Leak Detection and Isolation System STD DEP T1 2.14-1
(10) Isolates the flammability control system lines
(11 10) Isolates the drywell sumps drain lines
(12 11) Isolates the fission products monitor sampling and return lines
(13 12) Initiates withdrawal of the automated traversing incore probe
1.2.2.5.4 Reactor Core Isolation Cooling System STD DEP T1 2.4-3
The RCIC System provides makeup water to the reactor vessel when the vessel is isolated and is also part of the emergency core cooling network. The RCIC System uses a steam-driven turbine-pump unit and operates automatically in time and with sufficient coolant flow to maintain adequate water level in the reactor vessel for events defined in Section 5.4.
One division contains the RCIC System, which consists of a steam-driven turbine- which drives a pump assembly and the turbine and pump accessories. The system also includes piping, valves, and instrumentation necessary to implement several flow paths. The RCIC steam supply line branches off one of the main steamlines (leaving the RPV) and goes to the RCIC turbine with drainage provision to the main condenser. The turbine exhausts to the suppression pool with vacuum breaking protection. Makeup water is supplied from the condensate storage tank (CST) or the suppression pool with preferred source being the CST. RCIC pump discharge lines include the main discharge line to the feedwater line, a test return line to the suppression pool, and a minimum flow bypass line to the suppression pool and a cooling water supply line to auxiliary equipment.
Following a reactor scram, steam generation in the reactor core continues at a reduced rate due to the core fission product delay heat. The turbine condenser and the feedwater system supply the makeup water required to maintain reactor vessel inventory.
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1.2.2.6.5 Refueling Equipment STP DEP T1 2.5-1
The Reactor Building crane handles the spent fuel cask from the transport device to the cask loading pit. The refueling machine transfers the fuel assemblies between the storage area and the reactor core. New fuel bundles are handled by the Reactor Building crane.The bundles are stored in the new fuel vault on the reactor refueling floor and are transferred from the vault to the spent fuel pool with the Reactor Building crane auxiliary hook.
1.2.2.6.6 Fuel Storage Facility STP DEP T1 2.5-1
New and sSpent fuel storage racks are designed to prevent inadvertent criticality and load buckling. Sufficient cooling and shielding are provided to prevent excessive pool heatup and personnel exposure, respectively. The design of the fuel pool provides for corrosion resistance, adherence to Seismic Category I requirements, and prevention of keff from reaching 0.95 under dry or flooded conditions.
1.2.2.8.6 Multiplexing System Data Communication STD DEP T1 3.4-1
Data communication is accomplished through multipleThe Multiplexing System provides redundant and distributed control and instrumentation data communications networks tofunctions that support the monitoring and control of interfacing plant systems. The equipment system includes electrical devices and circuitry (such as multiplexing units, bus controllers, formatters and data buses) that connect sensors, display devices, controllers, and actuators which are part of these plant systems. The data commuication communication function Multiplexing System also includes the associated data acquisition and communication software required to support its function of plant-wide data and control distribution.
1.2.2.10.13 Solid Waste Management System STD DEP 11.4-1
The Solid Waste Management System provides for the safe handling, packaging, and short-term storage of radioactive solid and concentrated liquid wastes that are produced. Wet waste processed by this system is transferred to the solidification system, where it is solidified in containers. Dry active waste is surveyed and disposed of whenever possible via the provisions of 10 CFR 20.302 (a)applicable Federal and State regulations. The remaining combustible waste is compacted. Incinerator ash is compacted waste and shipped in containers for offsite disposal. Refer to Section 11.4 for a complete description of the solid waste management system.
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1.2.2.11.16 Generator STP DEP 10.2-1
The generator is a direct-driven, three-phase, 60 Hz, 27approximately 26 kV, 188.5 rad/s1800 rpm, conductor cooled, synchronous generator rated at approximately 16001610 MVA, at 0.90 power factor, 537.4 520 kPaG hydrogen pressure, and 0.60 approximately 0.5 short circuit ratio.
1.2.2.11.20 Exciter STP DEP 10.2-1
The generator exciter is driven by the main turbine a static excitation system and will have a response ratio that meets the plant voltage regulation requirements and the site specific grid requirements.
Excitation power is provided by the output of a dedicated winding located in the main generator transformer. This output is rectified by the stationary silicon diodethyristor rectifiers. The DC output of the rectifier banks then is applied to the main generator field through the generator collectors.
1.2.2.11.21 Main Condenser STP DEP 10.4-2
The main condenser is a multipressure single-pressure, three-shell deaerating type condenser or single pressure design as dictated by the site specific circulating water system and power generating heat sink. During plant operation, steam expanding through the low pressure turbines is directed downward into the main condenser and is condensed. The main condenser also serves as a heat sink for the turbine bypass system, emergency and high level feedwater heater and drain tank dumps, and various other startup drains and relief valve discharges.
1.2.2.13.2 Unit Auxiliary Transformers STD DEP 8.3-1
The unit auxiliary AC power system supplies power to unit loads that are non-safety- related and uses the main generator and/or offsite power as the normal power source with the reserve auxiliary transformers as a backup sources. The unit auxiliary transformer steps down the AC power to the 6900V13.8 kV and 4.16 kV station bus voltages.
1.2.2.13.3 Isolated Phase Bus STD DEP 8.3-1
The isolated phase bus duct system provides electrical interconnection from the main generator output terminals to the generator breaker and from the generator breaker to the low voltage terminals of the main transformer, and the high voltage terminals of the
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unit auxiliary transformers. During the time the main generator is off line, the generator breaker is open and power is fed to the unit auxiliary transformers by backfeeding from the main transformer. During startup, the generator breaker is closed at about 7%between 10% and 15% power to provide power to the main and the unit auxiliary transformers for normal operation of the plant.
A package cooling unit is supplied with the isolated bus duct system.
1.2.2.13.4 Non-Segregated Phase Bus and Cable STD DEP 8.3-1
The non-segregated phase bus or cable provides the electrical interconnection between the unit auxiliary transformers and their associated 6.9 kV metal cladmedium- voltage switchgear, and between the reserve auxiliary transformers and their associated medium-voltage switchgear.
1.2.2.13.5 Metal-clad Switchgear STD DEP 8.3-1
The metal-clad switchgear distributes the 6.9 kV 13.8 kV or 4.16kV power. Circuit breakers are drawout type, stored energy vacuum breakers. The switchgear interrupting rating shall be determined in accordance with requirements of ANSIIEEE C37.010.
1.2.2.13.13 Emergency Diesel Generator System STD DEP 8.3-1
The Emergency Diesel Generator System is supplied by three diesel generators. Each Class 1E division is supplied by a separate diesel generator. There are no provisions for transferring automatic transfer of Class 1E buses between standby AC power supplies or supplying more than one division of engineered safety features (ESF) from one diesel generator. This one-to-one relationship ensures that a failure of one diesel generator can affect only one ESF division. The diesel generators are housed in the Reactor Building which is a Seismic Category I structure, to comply with applicable NRC and IEEE design guides and criteria.
1.2.2.13.17 Lighting and Servicing Power Supply STD DEP 8.3-1
The design basis for the lighting facilities is the standard for the Illuminating Engineering Society. Special attention is given to areas where proper lighting is imperative during normal and emergency operations. The system design precludes the use of mercury vapor fixtures in the containment and fuel handling areas. The normal lighting systems are fed from the unit auxiliary transformers non-Class 1E Plant Investment Protection (PIP) buses that are backed up by the combustion turbine generator. Emergency power is supplied by engineered safety buses backed-up by
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diesel generators. Normal operation and regular simulated offsite power loss tests verify system integrity.
1.2.2.14.1 Reserve Auxiliary Transformers STD DEP 8.3-1
The reserve auxiliary transformer provides the alternate preferred feed for the Class 1E buses M/C, E, F, and G. It also provides an alternate feed to non-Class 1E 6.9 kV buses.
Each reserve auxiliary transformer provides alternate preferred feeds to two power generation buses and can feed any of the three plant investment protection buses and any of the three Class 1E 4.16 kV buses.
1.2.2.15.8 Flammability Control System (Not Used) STD DEP T1 2.14-1
A recombiner system is provided to control the concentration of hydrogen and oxygen produced by metal water reaction and radiolysis following a design basis accident in the primary containment.
1.2.2.16.5 Heating, Ventilating and Air Conditioning STD DEP 9.4-4
(9) The Turbine Island HVAC System maintains environmental conditions in the Turbine Building and the Electrical Equipment areas.
STP DEP 9.4-3
(10) The Service Building HVAC System maintains environmental conditions in the Service Building, including clean areas such as the Technical Support Center and Operations Support Center during emergency conditions.
The following site-specific supplement addresses COL License Information Item 9.17.
(11) The Radwaste Building HVAC System is engineered and designed to provide proper environmental conditions within all areas of the Radwaste Building during normal plant operation.
1.2.2.16.5.1 Potable and Sanitary Water System The information in this subsection of the reference ABWR is incorporated by reference with the following site-specific supplement.
The potable and sanitary water includes conceptual site-specific designs of a potable water system, a sanitary water system, a sewage treatment system, and a separate non-radioactive drain system. These systems are summarized in Subsections 9.2.4.1.3, 9.2.4.3.2, and 9.3.3.2.3, respectively.
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1.2.2.16.15 Control Building Annex STD DEP 1.2-1
The Control Building Annex is a nonsafety-related structure located adjacent to the Control Building. It houses the two nonsafety-related Reactor Internal Pump Motor Generator sets, control panels, and the cooling water lines, HVAC system, and electrical lines that support the MG sets. The reactor internal pump motor-generator set equipment performs no safety-related function.
1.2.3 COL License Information 1.2.3.1 Plant Design and Aging Management The information in this subsection of the reference ABWR DCD is deleted. The information required by COL Information Item 1.1a is provided in Subsection 1.2.1.3.
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Figure 1.2-1 Site Plan
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The following figures in Chapter 21 have been revised:
Figure 1.2-2 Reactor Building, Arrangement Elevation, Section A-A
Figure 1.2-8 Reactor Building, Arrangement Plan at Elevation 12300 mm
Figure 1.2-23a Radwaste Building at Elevation 1500 mm
Figure 1.2-23b Radwaste Building at Elevation 4800 mm
Figure 1.2-23c Radwaste Building at Elevation 12300 mm
Figure 1.2-23d Radwaste Building at Elevation 21000 mm
Figure 1.2-23e Radwaste Building, Section A-A
Figure 1.2-24 Turbine Building, General Arrangement at Elevation 2300 mm
Figure 1.2-25 Turbine Building, General Arrangement at Elevation 6300 mm
Figure 1.2-26 Turbine Building, General Arrangement at Elevation 12300 mm
Figure 1.2-27 Turbine Building, General Arrangement at Elevation 19700mm
Figure 1.2-28 Turbine Building, General Arrangement at Elevation 24400mm
Figure 1.2-29 Turbine Building, General Arrangement at Elevation 27800mm
Figure 1.2-30 Turbine Building, General Arrangement at Elevation 38300mm
Figure 1.2-31 Turbine Building, General Arrangement at Elevation 47200mm
Figure 1.2-32 Turbine Building, General Arrangement at Section A-A
Figure 1.2-33 Turbine Building, General Arrangement, at Section B-B
The following supplemental figures are added to Chapter 21:
Figure 1.2-34 UHS Tower Plans
Figure 1.2-35 UHS Tower Sections
Figure 1.2-36 RSW Pumphouse, Tunnel Plans and Sections
Figure 1.2-37 Plot Plan
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1.3 Comparison Tables The information in this section of the reference ABWR DCD, including all subsections and tables, is incorporated by reference with no departures or supplements.
Comparison Tables 1.3-1/2
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1.4 Identification of Agents and Contractors The information in this section of the reference ABWR DCD, as modified by the STP Nuclear Operating Company Application to Amend the Design Certification rule for the U.S. Advanced Boiling Water Reactor (ABWR), "ABWR STP Aircraft Impact Assessment (AIA) Amendment Revision 3," dated September 23, 2010 is incorporated by reference, with the following site-specific supplement.
NINA is the licensee responsible for design and construction of STP 3 & 4. STPNOC is the licensee responsible for operation and maintenance of STP 3 & 4. The design and construction of STP 3 & 4 will be completed by a consortium of Toshiba America Nuclear Energy (Toshiba) and Stone & Webster, a wholly owned subsidiary of Shaw Group Incorporated, acting in conjunction with subcontractors including Westinghouse and Sargent & Lundy. Throughout this document the Consortium participant for the Shaw Group Inc. will be referred to as Shaw. Toshiba and Shaw will have overall responsibility for design and configuration control. Sargent & Lundy will provide architect/engineer services. Westinghouse will provide engineering services, including design of instrumentation and controls.
The measures taken to address the potential for foreign ownership, domination control or influence of the licensees are addressed in the Negation Action Plan provided as Appendix 1D.
1.4.4 Identification of Agents and Contractors - STP 3 & 4 NINA executed a contract for Engineering, Procurement, and Construction (EPC) of the facilities with a Consortium comprised of Toshiba and Stone & Webster, a wholly owned subsidiary of Shaw Group Incorporated. The Consortium will act as the ABWR provider and architect-engineer for STP Units 3 and 4. NINA, as the constructor of STP Units 3 and 4, has delegated responsibility for physical construction activities to the Consortium.
The design and construction of STP 3 & 4 will be completed by Toshiba and Shaw acting in conjunction with subcontractors including Westinghouse and Sargent & Lundy. Toshiba and Shaw will have overall responsiblity for design and configuration control. Sargent & Lundy will provide architect/engineer services for the Nuclear Island. Westinghouse will provide engineering services, including design of instrumentation and controls.
Toshiba is responsible for the overall plant design of the Nuclear Island, procurement of primary NSSS equipment and power block major components including the Turbine Generator, and plant training simulator. Shaw is responsible for site development, overall plant design of the Turbine Island, construction, site specific design related work, secondary equipment procurement, module fabrication, and supply of bulk materials and commodities. Toshiba and Shaw are jointly responsible for testing and startup.
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1.4.4.1 Nuclear Innovation North America LLC NINA was formed in 2008. Its focus is to market and promote ABWR nuclear technology, and to develop and construct ABWR nuclear power generation facilities in the U.S. NINA assumed responsibility for the design and construction of STP 3 & 4 in 2011. It organized itself for this purpose by transitioning the previously existing STPNOC organization responsible for the development of STP 3 & 4 from STPNOC to NINA. This transition included the programs, processes and procedures developed by STPNOC for STP 3 & 4. NINA's STP 3 & 4 organization is focused on the design and construction of STP 3 & 4 and coordination with STPNOC for the operation of STP 3 & 4. After the 10CFR52.103(g) finding or authorization for interim operation pursuant to 10CFR52.103(c) is issued, NINA will provide services to STPNOC to support completion of construction.
1.4.4.2 STP Nuclear Operating Company STPNOC is the operator and license holder of STP 1 & 2 and will be the operator and license holder for STP 3 & 4 upon issuance of the 52.103(g) finding or authorization for interim operation pursuant to 10 CFR 52.103(c). During the construction period STPNOC will provide services to NINA that support the implementation of the Operational Programs and system operations during the test program.
STPNOC is a Texas non-profit corporation, created, controlled and financed by the owners of STP 1 & 2 specifically for the purpose of operating STP 1 & 2. STPNOC has had responsibility for the operation of STP 1 & 2 since November 17, 1997, when the Operating Licenses were amended to transfer this responsibility to STPNOC from Houston Lighting & Power Company.
STP 1 & 2 each utilizes a four-loop, pressurized water reactor (PWR) Nuclear Steam Supply System (NSSS) and supporting auxiliary systems designed by Westinghouse Electric Corporation. The rated core thermal power of each unit is 3,853 MWt. Each unit was originally designed for a net electrical power output of 1,250 MWe at 3.5 in. Hg abs. backpressure. Commercial operation was declared in August 1988 and June 1989 for STP 1 & 2, respectively.
1.4.4.3 Toshiba Power Systems Company Toshiba Power Systems Company is responsible for the Engineering, Procurement, and Construction (EPC) of STP Units 3 & 4. In this capacity Toshiba has overall project management responsibility for the design and construction of the facility, including support of the Combined License Application (COLA), in conjunction with the subcontractors described below.
Toshiba has extensive experience in the design, construction, and commissioning of the Advanced Boiling Water Reactor (ABWR) worldwide, having participated in the development of the common engineering documents, design of the ABWR systems, and construction of three ABWRs in Japan. The first ABWR plant, Kashiwazaki-Kariwa Unit No. 6, commenced commercial operation in 1996, followed by Unit No.7 in 1997, and Hamaoka Unit No. 5 in January 2005.
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1.4.4.4 Shaw Group Inc. Shaw Group Incorporated, as part of the Consortium, is responsible for the Engineering, Procurement, and Construction (EPC) of STP Units 3 & 4. In this capacity Shaw with Toshiba has overall project management responsibility for the design and construction of the facility, including support of the Combined License Application (COLA), in conjunction with the subcontractors described below.
Shaw is a Fortune 500 company which has been an active participant in the nuclear industry for nearly 60 years, from providing engineering and design services for Shippingport, the nation’s first commercial nuclear power plant, to the restart of Tennessee Valley Authority’s Browns Ferry Unit 1, which at the time was the largest nuclear construction project in the western hemisphere. Shaw continues to prove its leadership role in the nuclear industry by being part of the AP1000 Consortium. Shaw is part of a vertically integrated company, Shaw Group, Inc., which has nearly 180 offices worldwide and over 28,000 employees, of which approximately 3,100 are nuclear professionals offering nuclear services on four continents.
1.4.4.5 Westinghouse Electric Corporation Westinghouse Electric Corporation (WEC) has significant experience in the design, construction, inspection and maintenance of domestic and international nuclear power plants.
1.4.4.6 Sargent & Lundy Sargent & Lundy provides engineering services for STP 3 & 4, specifically the design of the Nuclear Island, including the Reactor Building, Control Building, Radwaste Building and Ultimate Heat Sink.
For more than 100 years Sargent & Lundy has provided comprehensive consulting, engineering, design, and analysis for electric power generation and power delivery projects worldwide. Sargent & Lundy has a large, highly experienced staff solely dedicated to the energy business.
1.4.4.7 Other Contractors Several specialized consultants assisted in developing the COLA.
1.4.4.7.1 Tetra Tech NUS, Inc. Tetra Tech NUS, Inc. performed data collection and analysis, and prepared sections of the Final Safety Analysis Report (FSAR) and Environmental Report (ER), including socioeconomics/demographics, ecology and ecological impacts of construction and operation, land and water use impacts of construction and operation, transmission system impacts of construction and operation, radiological impacts of operation, uranium fuel cycle and transportation of radioactive materials impacts, and environmental impacts of postulated accidents.
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Tetra Tech NUS, Inc. has prepared sections of the FSAR and ER for several Early Site Permit (ESP) and COLAs, including the North Anna and Vogtle ESP applications, and the V.C. Summer and Calvert Cliffs COLAs. In addition, Tetra Tech NUS has prepared ERs for license renewal applications for more than 30 nuclear plants.
1.4.4.7.2 MACTEC Engineering and Consulting, Inc. MACTEC Engineering and Consulting, Inc. (MACTEC) performed geotechnical field investigations and laboratory testing in support of FSAR Section 2.5, Geology, Seismology, and Geotechnical Engineering. That effort included performing standard penetration tests; obtaining core samples and rock cores; performing cone penetrometer tests, cross-hole seismic tests, and laboratory tests of soil and rock samples; installing ground water observation wells; and preparing a data report.
MACTEC has implemented subsurface site geotechnical investigations for several projects. These include the Vogtle and North Anna ESP applications, and the V.C. Summer, North Anna, and Vogtle COLAs. MACTEC is also involved with other ESP applications and COLAs presently being developed.
1.4.4.7.3 William Lettis & Associates, Inc. William Lettis & Associates, Inc. (WLA) performed geologic mapping and the characterization of seismic sources in support of FSAR Section 2.5, including literature review, geologic field reconnaissance, review and evaluation of existing seismic source characterization models, identification and characterization of any new or different sources, and preparation of the related FSAR sections.
WLA has implemented geologic reconnaissance investigations and research to support ESP applications and COLAs for several projects. These include the Vogtle and North Anna ESP applications, and the Calvert Cliffs and V.C. Summer COLAs. WLA is also involved with other ESP applications and COLAs presently being developed.
1.4.4.7.4 Risk Engineering, Inc. Risk Engineering, Inc. (REI) performed probabilistic seismic hazard assessments and related sensitivity analyses in support of FSAR Section 2.5. These assignments included sensitivity analyses of seismic source parameters and updated ground motion attenuation relationships, development of updated safe shutdown earthquake ground motion values, and preparation of the related FSAR sections.
REI has performed probabilistic seismic hazard analyses to support ESP applications and COLAs for several projects. These include the Vogtle and North Anna ESP applications, and the Calvert Cliffs, V.C. Summer, and North Anna COLAs. REI is also involved with other ESP applications and COLAs presently being developed.
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1.4.4.7.5 Bechtel Corporation Bechtel supports project licensing primarily with regard to the ER and site characterization. Bechtel, headquartered in San Francisco, is the nation’s largest power contractor. Bechtel has a history of supporting the nuclear power industry, beginning with the construction in 1950 of the EBR-1 reactor. Since then, Bechtel has engineered and constructed more than 60,000 MWe of nuclear power capacity worldwide. Currently, Bechtel has 40,000 employees and has completed 22,000 projects in 140 different countries around the globe.
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1.5 Requirements for Further Technical Information The information in this section of the reference ABWR DCD is incorporated by reference with no departures or supplements.
Requirements for Further Technical Information 1.5-1/2
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1.6 GE Topical Reports and Other Documents The information in this section of the reference ABWR DCD, including all tables, is incorporated by reference with the following supplement.
Table 1.6-2 is a supplemental tabulation of Reports incorporated by reference as part of the combined license application.
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Table 1.6-2 Additional Reports Incorporated by Reference Referenced in Report No. Title FSAR Section
NEDO-32686-A Utility Resolution Guidance for ECCS Suction Strainer Blockage, App 6C October 1998
HI-2135462 Holtec International “Licensing Report for South Texas Project 9.1 UNITS 3 & 4 ABWR Spent Fuel Racks” Revision 2
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1.7 Drawings The information in this section of the reference ABWR DCD, including all tables and figures, is incorporated by reference with the following departures and site-specific supplements.
STD DEP T1 2.14-1 (Table 1.7-1)
STD DEP T1 3.4-1 (Table 1.7-5)
Table 1.7-6 is a supplemental tabulation of additional or updated instrumentation and control (I&C) functional diagrams and electrical one-line diagrams, including legends for electrical power, I&C, lighting, and communication drawings.
Table 1.7-7 is a supplemental tabulation of system drawings and system designators for systems not included in the reference ABWR DCD. The information includes the applicable drawing legends and notes.
1.7.1 Piping and Instrumentation and Process Flow Drawings STD DEP T1 2.14-1 (Table 1.7-1)
Table 1.7-1 contains a list of system piping and instrumentation diagrams (P&ID) and process flow diagrams (PFD) provided in Tier 2. Figure 1.7-1, sheets 1 and 2 define the symbols used on these drawings.
1.7.6 COL License Information 1.7.6.1 P&ID Pipe Schedules The following standard supplement addresses COL License Information Item 1.2.
The minimum pipe schedule for ANSI nominal pipe sizes are identified below for any individual piping system shown on a Piping and Instrumentation Diagram (P&ID).
ASME Section III ASME B31.1 Carbon Steel and Alloy Pipe 50mm (2 inch) and smaller Schedule 80 Schedule 80 65mm (2-1/2 inch) and larger Standard Weight Standard Weight Stainless Steel Pipe 50mm (2 inch) and smaller Schedule 40S Schedule 40S 65mm (2-1/2 inch) through 150mm (6 inch) Schedule 10S Schedule 10S 200mm (8 inch) through 300mm (12 inch) Schedule 40S Schedule 40S 350mm (14 inch) and larger 10mm (0.375 inch) 10mm (0.375 inch)
Drawings 1.7-1 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 1.7-1 Piping and Instrumentation and Process Flow Diagrams
Tier 2 Fig. No. Title Type 6.2-40 Flammability Control System P&ID
1.7-2 Drawings Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 1.7-5: Drawing Standards
1.4.5 Instrument Numbering 601 to 999 Instruments installed in main control room, including instrument functions performed by multiplexer data communication. The instrument number assigned to the latter is prefixed by the letter Z. 1.4.6 Numbering Within a Loop Instruments or instrument functions performed by the multiplexer data communication in the same loop have the same last two numbers. Instruments located in the main control room that receive signals from locally installed instruments in the same loop are numbered by adding 600 to the local or local panel-mounted instrument number in the loop.
Drawings 1.7-3 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 1.7-6 Additional or Updated I&C and Electrical Drawings Figure No. Title Type 5.2-8 Leak Detection and Isolation System IED 7.2-9 Reactor Protection System IED 7.2-10 Reactor Protection System IBD 7.3-1 High Pressure Core Flooder System IBD 7.3-2 Nuclear Boiler System IBD 7.3-3 Reactor Core Isolation Cooling System IBD 7.3-4 Residual Heat Removal System IBD 7.3-5 Leak Detection and Isolation System IBD 7.4-2 Remote Shutdown System IED 7.4-3 Remote Shutdown System IBD 7.6-1 Neutron Monitoring System IED 7.6-2 Neutron Monitoring System IBD 7.6-5 Process Radiation Monitoring System IED 7.6-11 Suppression Pool Temperature Monitoring System IED 7.6-12 Suppression Pool Temperature Monitoring System IBD 7.7-2 Rod Control and Information System IED 7.7-3 Rod Control and Information System IBD 7.7-4 Control Rod Drive System IBD 7.7-5 Recirculation Flow Control System IED 7.7-7 Recirculation Flow Control System IBD 7.7-8 Feedwater Control System IED 7.7-9 Feedwater Control System IBD 7.7-12 Steam Bypass and Pressure Control System IED 7.7-13 Steam Bypass and Pressure Control System IBD 8.2-1 Power Distribution System Routing Diagram SLD 8.2-2 345 kV General Arrangement SLD 8.2-3 345 kV Switchyard Single Line Diagram SLD 8.2-4 345 kV Switchyard Arrangement SLD 8.2-5 345 kV Transmission Configuration Map SLD 8.2-6 Topographic Map of 345 kV Transmission Line (Blessing SE Line) SLD 8.3-1 Electrical Power Distribution System SLD 8.3-2 Instrument and Control Power Supply System SLD
1.7-4 Drawings Rev. 12 STP 3 & 4 Final Safety Analysis Report
Table 1.7-7 System Drawings Not Included in the ABWR DCD
Figure No. Title Type 9.2-9 Potable Water System P&ID 9.3-10 Breathing Air System P&ID 9.3-11 Radioactive Drain Transfer System P&ID 9.3-12 Non-Radioactive Drainage System P&ID 11.2-2 Radwaste System P&ID
Drawings 1.7-5/6
Rev. 12
STP 3 & 4 Final Safety Analysis Report
1.8 Conformance with Standard Review Plan and Applicability of Codes and Standards The information in this section of the reference ABWR DCD, including all subsections and tables, as modified by the STP Nuclear Operating Company Application to Amend the Design Certification rule for the U.S. Advanced Boiling Water Reactor (ABWR), "ABWR STP Aircraft Impact Assessment (AIA) Amendment Revision 3," dated September 23, 2010 is incorporated by reference with the following departures, standard supplement, and site-specific supplement (Table 1.8-21a).
STD DEP T1 2.14-1 (Table 1.8-20)
STD DEP T1 2.15-1 (Table 1.8-20)
STD DEP 1.8-1 (Table 1.8-7, Table 1.8-20, Table 1.8-21)
STD DEP 5A-1 (Table 1.8-20)
STD DEP 6C-1 (Table 1.8-20)
STD DEP 9.1-1 (Table 1.8-21)
STD DEP 9.5-1 (Table 1.8-20)
STD DEP 11.2-1 (Table 1.8-20)
STD DEP 11.4-1 (Table 1.8-20)
Revisions have been made to Table 1.8-20 and are summarized here. The STP 3 & 4 FSAR conforms with the following revisions of Regulatory Guides (RGs).
RG 1.75 Rev. 3
RG 1.82, Rev. 3
RG 1.84, Rev. 33
RG 1.136, Rev. 3
RG 1.142, Rev. 2
RG 1.143, Rev. 2 for the Radwaste Building, Radwaste Tunnel, and liquid and solid radwaste processing systems. Rev. 1 is incorporated by reference for the Turbine Building and offgas system.
RG 1.153, Rev. 1
RG 1.199, Rev. 0
RG 1.85 has been deleted (withdrawn).
Conformance with Standard Review Plan and Applicability of Codes and Standards 1.8-1 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Revisions have been made to Table 1.8-21 and are summarized here. The STP 3 & 4 FSAR conforms with the following Codes and Standards.
ACI 349, 1997
ASME BPVC, Section III, Division 2, 2001 Edition with 2003 Addenda
MIL STD-461E, 1999
MIL STD-462E, 1999
IEEE 279, 1971 has been replaced by IEEE 603, 1991
IEEE 384, 1992
IEEE 603, 1991
MIL STD-1478, 1991 has been cancelled by the Dept. of Defense, and has been deleted.
International Building Code, 2006
Additionally, the following standard supplemental information corrects an omission from DCD Table 1.8-21.
IEEE 665, 1995
Table 1.8-7 Summary of Differences from SRP Section 7
Specific SRP Summary Description Subsection Where SRP Section Acceptance Criteria of Difference Discussed 7.1 Table 7-1: 1a RHR Annunciation at 7.3.2.3.2 (1) IEEE-279, 4.19 loop level. 7.3.2.4.2 (1) 7.4.2.3.2 (1)
1.8-2 Conformance with Standard Review Plan and Applicability of Codes and Standards Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 1.8-20 NRC Regulatory Guides Applicable to ABWR Appl. Issued ABWR RG No. Regulatory Guide Title Rev. Date Applicable? Comments 1.7 Control of Combustible Gas Concentrations in 23 11/78 Yes Containment Following a Loss-of-Coolant 3/07 Accident [1.53 Application of the Single-Failure Criterion to 0 6/73 Yes] Safety Systems(12) [1.75 Physical Independence of Electric Systems 2 9/78 Yes](4) 3 2/05 1.118 Periodic Testing of Electric Power and 2 6/78 Yes Protection System(12) [1.152 Criteria for Programmable Digital Computer 0 2 11/85 Yes](4) System Software in Safety-Related Systems 1/06 of Nuclear Power Plants(10) 1.168 Verification, Validation, Reviews and Audits 1 2004 Yes for Digital Computer Software Used in Safety Systems of Nuclear Power Plants 1.169 Configuration Management Plans for Digital 09/97Yes Computer Software Used in Safety Systems of Nuclear Power Plants 1.170 Software Test Documentation for Digital 09/97Yes Computer Software Used in Safety Systems of Nuclear Power Plants 1.171 Software Unit Testing for Digital Computer 09/97Yes Software Used in Safety Systems of Nuclear Power Plants 1.172 Software Requirements Specifications for 09/97Yes Digital Computer Software Used in Safety Systems of Nuclear Power Plants 1.173 Developing Software Life Cycle Process for 09/97Yes Digital Computer Software Used in Safety Systems of Nuclear Power Plants 1.180 Guidelines for Evaluating Electromagnetic 1 10/03 Yes and Radio- Frequency Interference in Safety- Related Instrumentation and Control Systems Instrumentation and Control Systems6(11) 1.209 Guidelines for Environmental Qualification of 0 03/07 Yes Safety-Related Computer-Based Instrumentation and Control Systems in Nuclear Power Plants 1.82 Water Sources for Long-Term Recirculation 1 11/85 Yes Cooling Following Loss-of-Coolant Accident 3 11/03
Conformance with Standard Review Plan and Applicability of Codes and Standards 1.8-3 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 1.8-20 NRC Regulatory Guides Applicable to ABWR (Continued)
1.199 Anchoring Components and Structural 0 11/03 Yes Supports in Concrete [1.84 Design and Fabrication Code Case 27 11/90 Yes](1) Acceptability, ASME Section III, Division 1 33 8/05 1.85 Materials Code Case Acceptability, 27 11/90 Yes ASME Section III, Division 1 1.108 Periodic Testing of Diesel Generator Units 1 8/77sup Yes Replaced by Used as Onsite Electric Power Systems at ersede RG. 1.9 Nuclear Power Plants d 1.136 Materials, Construction, and Testing of 2 7/81 Yes Concrete Containments (Articles CC-1000, 3 3/07 -2000, and -4000 through -6000 of the “Code for Concrete Reactor Vessels and Containment”) 1.142 Safety-Related Concrete Structures for 1 11/81 Yes Nuclear Power Plants (Other Than Reactor 2 11/01 Vessels and Containments) 1.143 Guidance for Radioactive Waste Management 1 10/79 Yes (Rev 1 - Systems, Structures, and Components incorporated by Installed in Light-Water-Cooled Nuclear reference from Power Plants the DCD) 2 11/01 Yes (Rev 2 - RWB, radwaste pipe tunnel, and liquid and solid waste management systems) 1.150 Ultrasonic Testing of Reactor Vessel Welds 1 2/83 yes During Preservice and Inservice Examinations [1.153 Criteria for Power, Instrumentation, and 0 12/85 Yes](4) Control Portions of Safety Systems 1 6/96 1.189 Fire Protection for Operating Nuclear Power 1 3/2007 Yes Plants 1.189 Fire Protection for Operating Nuclear Power 2 10/2009 Yes Only as it Plants applies to Single and Multiple Spurious Operation Analysis
1.8-4 Conformance with Standard Review Plan and Applicability of Codes and Standards Rev. 12
STP 3 & 4 Final Safety Analysis Report
5 The Common Q Digital Platform was submitted for generic use and was approved for reference as described in Topical Report WCAP-16097-P-A, Revision 0, "Common Qualified Platform Topical Report.” This topical report includes the SERs dated August 11, 2000, June 22, 2001, and February 4, 2003, and is consistent with the referenced Regulatory Guide revisions identified in the comments. The Westinghouse "Software Program Manual for Common Q Systems" (SPM), WCAP-16096-NP-A also incorporates standards and Regulatory Guide requirements. The requirements that this platform were licensed to are submitted as an acceptable alternate to current requirements based on the original NRC review and SERs. 6 RG 1.180 endorses IEEE 1050-1996. The digital instrumentation and controls systems conform to IEEE 1050-2004 as shown in Table 1.8-21. 7 RG 1.209 endorses IEEE 323-2003. The ELCS conforms to IEEE 323-1983 as discussed in Note 5.
Conformance with Standard Review Plan and Applicability of Codes and Standards 1.8-5 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 1.8-21 Industrial Codes and Standards(*) Applicable to ABWR Code or Standard Number Year Title American Concrete Institute (ACI) [349(†) 1980 1997 Code Requirements for Nuclear Safety-Related Concrete Structures](1)(13) American Society of Mechanical Engineers (ASME) NOG-1 2004 Rules for Construction of Overhead and Gantry Cranes [SEC III 1989 BPVC Section III, Division 1, Rules for Construction of Nuclear Power Plant Components](6)(8) [Sec III 2001 with BPVC Section III, Division 2, Rules for Construction of Nuclear 2003 Power Plant Components](8) Addenda Institute of Electrical and Electronics Engineers (IEEE) 7-4.3.2 1982 2003 Standard Criteria for Digital Computers Used in Safety Systems of Nuclear Power Generation Stations [279 1971 Criteria for Protection Systems for NPGS](3)(4) [323† 1974 Qualifying Class lE Equipment for NPGS](3)(4)(7)(12) [338† 1977 Criteria for the Periodic SurveillanceTesting of NPGS Safety Systems] (3)(9)(12) 379† 1977 Standard Application of the Single-Failure Criterion to NPGS Safety Systems(12) [384(†) 1981 1992 Criteria for Independence of Class 1E Equipment and Circuits](3) [603(†) 1980 1991 IEEE Standard Criteria for Safety Systems for Nuclear Power Generating Stations, including the corrective sheet dated January 30, 1995](3)/(4) 665 1995 IEEE Guide for Generating Station Grounding [828† 1983 1990 Standard for Software Configuration Management Plans] (3)(4) [830† 1984 1993 Recommended Practice for Software Requirements Specifications] (3)(4) 1008 1987 Standard for Software Unit Testing [1012† 1986 1998 Standard for Software Verification and Validation] (3)(4) 1028 1997 Standard for Software Reviews and Audits [1050 1989 2004 Guide for Instrumentation and Control Equipment Grounding in Generating Stations] (3)(4) 1074 1995 Standard for Developing Software Life Cycle Processes U.S. Military (MIL)
1.8-6 Conformance with Standard Review Plan and Applicability of Codes and Standards Rev. 12 STP 3 & 4 Final Safety Analysis Report
Table 1.8-21 Industrial Codes and Standards(*) Applicable to ABWR (Continued) [STD-461C E 1987 1999 Electromagnetic Emission and Susceptibility Requirements for the Control of Electromagnetic Interference](3)(4) [STD-462E 1967 1999 Measurement of Electromagnetic Interference Characteristics](3)(4) [STD-1478 1991 Task Performance Analysis](5) Others [IEC 801-2 1991 Electronic Capability for Industrial-Process Measurement and Control Equipment](3) [IEC 61000 2001 Electromagnetic Compatibility (EMC) - Part 4-2: Testing and Measurement Techniques - Electrostatic Discharge Immunity Test](3) UBC 1991 Uniform Building Code IBC 2006 International Building Code Notes: (1)See Subsection 3.8.3.2 for restriction to use of these. (3)See Section 7A.1(1). (4)See Section 7A.1(2). (6)See Subsection 3.8.1.1.1 for specific restriction of change to this edition. (8)See Subsection 3.9.1.7 for specific restriction of change to this edition in application to piping design. See Table 3.2-3 for the restricted Subsections of this Code as applied to piping design only. (10) The DI&C Systems will be evaluated for compliance with revised cyber security guidance being developed by the NRC and industry as computer security guidance to be issued as Secure Development and Operational Environment (SDOE) in the context of requirements in Revision 3 to Regulatory Guide 1.152 (DG-1249). (11) RG 1.180 endorses IEEE 1050-1996. The digital instrumentation and controls systems conform to IEEE 1050- 2004 as shown in Table 1.8-21. (12) The DI&C Systems will comply with current RG 1.53 Rev. 2 (11/03), RG 1.118 Rev. 3 (1995), IEEE 323-2003, IEEE 338-1987, and IEEE 379-2000. (13) ACI 349-97 references ASTM C289-81 for testing potential reactivity of aggregates (chemical). Additional testing per ASTM C1260 and C1293 will be performed.
(*) The listing of a code or standard does not necessarily mean that it is applicable in its entirety. (†)Also an ANSI code (i.e. ANSI/ASME, ANSI/ANS, ANS/IEEE etc.).
Conformance with Standard Review Plan and Applicability of Codes and Standards 1.8-7 Rev. 12 STP 3 & 4 Final Safety Analysis Report
Table 1.8-21a Codes and Standards for Site-Specific Systems Code or Standard Number Year Title American Concrete Institute (ACI) 349 1997 Code Requirements for Nuclear Safety-Related Concrete Structures 350 2001 Code Requirements for Environmental Engineering Concrete Structures, and Commentary (ACI 350R-01) 350.1 2001 Tightness Testing of Environmental Engineering Concrete Structures, and Commentary (ACI 350.1R-01) American Institute of Steel Construction (AISC) N690† 1994* Specifications for the Design, Fabrication and Erection of Steel Safety-Related Structures for Nuclear Facilities * (including Supplement 2) American Nuclear Society (ANS) 2.8 1992 Determining Design Basis Flooding at Power Reactor Sites 3.11 2005 Determining Meteorological Information at Nuclear Facilities 5.1 2005 Decay Heat Power in Light Water Reactors 40.37 200x Mobile Radioactive Waste Processing Systems 55.1 1992 Solid Radwaste Processing System for Light Water Reactor Plants 55.6 1993 Liquid Radioactive Waste Processing System for Light Water Reactor Plants 57.1 2005 Design Requirements for Light Water Reactor Fuel Handling Systems 57.2 1983 Design Requirements for Light Water Reactor Spent Fuel Storage Facilities at Nuclear Power Plants 57.3 1983 Design Requirements for New Fuel Storage Facilities at Light Water Reactor Plants American Petroleum Institute (API) 610 2004 Centrifugal Pumps for Petroleum, Petrochemical and Natural Gas Industries 620 2002 Design and Construction of Large, Welded, Low-Pressure Storage Tanks (with June 2004 Addenda) 650 2007 Welded Steel Tanks for Oil Storage, Addendum 3 674 1995 Positive Displacement Pumps - Reciprocating 675 1994 Positive Displacement Pumps – Controlled Volume American Society of Civil Engineers (ASCE) 4 1998 Seismic Analysis of Safety-Related Nuclear Structures (and Commentary) 43 2005 Seismic Design Criteria for Structures, Systems and Components Nuclear Facilities
1.8-8 Conformance with Standard Review Plan and Applicability of Codes and Standards Rev. 12 STP 3 & 4 Final Safety Analysis Report
Table 1.8-21a Codes and Standards for Site-Specific Systems (Continued) Code or Standard Number Year Title American Society of Civil Engineers / Structural Engineering Institute (ASCE/SEI) 7 2005 Minimum Design Loads for Buildings and Other Structures American Society of Mechanical Engineers (ASME) AG-1 1997 Code on Nuclear Air and Gas Treatment B30.2 2005 Overhead and Gantry Cranes (Top Running Bridge, Single or Multiple Girder, Top Running Trolley Hoist) B30.9 2006 Slings B30.10 2005 Hooks B30.11 2004 Monorails and Underhung Cranes B30.16 2007 Overhead Hoists (Underhung) B31.1 2004 Power Piping (Includes 2006 Addenda) B31.3 2006 Process Piping N13.1 1999 Guide to Sampling Airborne Radioactive Materials in Nuclear Facilities N14.6 1993 Special Lifting Devices for Shipping Containers Weighing 10,000 Pounds (4500 kg) or More for Nuclear Materials N510 1995 Testing of Nuclear Air-Cleaning Systems NOG-1 2004 Rules for Construction of Overhead and Gantry Cranes BPVC 2001 Rules for Construction of Nuclear Power Plant Components (including 2003 Sec III Addenda) BPVC 2004 Rules for Construction of Pressure Vessels Sec VIII BPVC 2004 Rules for Inservice Inspection of Nuclear Power Plant Components Sec XI OM 2004 Code for Operation and Maintenance of Nuclear Power Plants OM-S/G 2007 Requirements for Preoperational and Initial Startup Vibration Testing of Nuclear Power Plant Piping Systems Institute of Electrical and Electronics Engineers (IEEE) 384 1992 Criteria for Independence of Class 1E Equipment and Circuits 603 1991 IEEE Standard Criteria for Safety Systems for Nuclear Power Generating Stations 666 2007 Design Guide for Electric Power Service Systems for Generating Stations C62.23 1995 Application Guide for Surge Protection of Electric Generating Plants
Conformance with Standard Review Plan and Applicability of Codes and Standards 1.8-9 Rev. 12 STP 3 & 4 Final Safety Analysis Report
Table 1.8-21a Codes and Standards for Site-Specific Systems (Continued) Code or Standard Number Year Title International Code Council (ICC) IPC 2003 International Plumbing Code
1.8-10 Conformance with Standard Review Plan and Applicability of Codes and Standards Rev. 12
STP 3 & 4 Final Safety Analysis Report
1.8S Site Parameters, Interface Requirements, COL License Information Items, and Conceptual Design Information 1.8S.1 Conformance with Site Parameters The site parameters assumed for the ABWR Design Certification are found in Chapter 5.0 of Tier 1 and Chapter 2.0 of Tier 2 of the reference ABWR DCD.
The conformance of the STP 3 & 4 site with these site parameters is evaluated in FSAR Chapter 2.0. Table 1.8S-1 provides a cross-reference to the FSAR sections in which conformance with each of the site parameters is demonstrated.
1.8S.2 Conformance to Interface Requirements Plant design interfaces are the interfaces between the certified design and the remainder of the proposed facility design (i.e., site-specific designs).
The interface requirements for completing site-specific designs for the facility are addressed in Tier 1, Chapter 4.0 of the reference ABWR DCD. Table 1.8S-2 provides a cross-reference to the FSAR sections in which conformance to the interface requirements is described.
1.8S.3 Response to COL License Information Items The list of the ABWR COL license information items is found in Section 1.9 of Tier 2 of the reference ABWR DCD. These COL license information items include providing completed design information for the remainder of the proposed facility referencing the reference ABWR DCD, identification of site characteristics, completion of analyses and design reports for as-built plant systems, development and implementation of operational programs, completion of designs included in design acceptance criteria, etc.
FSAR Section 1.9 provides a cross-reference to the FSAR sections in which these COL license information items are addressed.
1.8S.4 Replacement of Conceptual Design Information The reference ABWR DCD includes conceptual designs for certain systems that are outside the scope of the standard design and are site-specific. The FSAR replaces the conceptual design information with a description and evaluation of the site-specific design. Table 1.8S-3 identifies the FSAR sections that replace the conceptual design information. These sections address the impact of any differences between the conceptual and site-specific design on the standard design and the design probabilistic risk assessment.
Site Parameters, Interface Requirements, COL License Information Items, and Conceptual Design Information 1.8S-1 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 1.8S-1 FSAR Sections that Demonstrate Conformance to Site Parameters Parameter FSAR Section Maximum Ground Water Level 2.3.2.30 Maximum Flood (or Tsunami) Level 2.3.2.13 Precipitation (for Roof Design) 2.3.2.7 Ambient Design Temperature 2.3.2.7 Extreme Wind 2.3.2.7 Tornado 2.3.2.7 Soil Properties 2.3.2.28 Seismology 2.3.1.2 Meteorological Dispersion (Chi/Q) 2.3.2.9 and 2.3.2.10
1.8S-2 Site Parameters, Interface Requirements, COL License Information Items, and Conceptual Design Information Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 1.8S-2 FSAR Sections that Demonstrate Conformance to Interface Requirements
ABWR DCD Design Interface FSAR Section Ultimate Heat Sink 9.2.5 Offsite Power System 8.2 Makeup Water Preparation System 9.2.8 Potable and Sanitary Water System 9.2.4 Reactor Service Water System 9.2.15 Turbine Service Water System 9.2.16 Communication System 9.5.2 Site Security 13.6 Circulating Water System 10.4.5 Heating, Ventilating and Air Conditioning 9.4
Site Parameters, Interface Requirements, COL License Information Items, and Conceptual Design Information 1.8S-3 Rev. 12 STP 3 & 4 Final Safety Analysis Report
Table 1.8S-3 FSAR Sections that Replace Conceptual Design Information
ABWR Conceptual Design Information FSAR Section Ultimate Heat Sink 9.2.5 Makeup Water Preparation System 9.2.8 Potable & Sanitary Water System 9.2.4 Reactor Service Water System 9.2.15 Turbine Service Water System 9.2.16 Non-Radioactive Drains 9.3.3.2 Power Cycle Heat Sink 10.4.5.8 Offsite Power System 8.2.5 Communication System 9.5.2 Site Security 13.6 Circulating Water System 10.4.5 HVAC 9.4
1.8S-4 Site Parameters, Interface Requirements, COL License Information Items, and Conceptual Design Information Rev. 12
STP 3 & 4 Final Safety Analysis Report
1.9 COL License Information The information in this section of the reference ABWR DCD, including all tables, is incorporated by reference with the following departure.
STD DEP T1 3.4-1 (Table 1.9-1)
COL License Information 1.9-1 Rev. 12 STP 3 & 4 Final Safety Analysis Report
Table 1.9-1 Summary of ABWR Standard Plant COL License Information Item No. Subject Subsection 19.8 Action to Avoid Common-Cause Failures in the Essential Multiplexing 19.9.8 System (EMUX)Communication Functions (ECFs) and Other Common- Cause Failures
1.9-2 COL License Information Rev. 12
STP 3 & 4 Final Safety Analysis Report
1.9S Conformance with Regulatory Criteria 1.9S.1 Conformance with Regulatory Guides Table 1.9S-1 lists the applicable Division 1 and Division 8 Regulatory Guides (RGs) effective in March 2007 with which STP 3 & 4 conform for the site-specific portions of the facility design not included in the reference ABWR DCD, as well as those RGs effective after March 2007 that were incorporated during the application review. The operational aspects of the facility are included. The table also includes those RGs with which the departures taken from the reference ABWR DCD conform. Table 1.9S-2 addresses STP 3 & 4 conformance with those RGs annotated as “COL Applicant” in the reference ABWR DCD Table 1.8-20.
Division 4 RGs are addressed in the Environmental Report with one exception for RG 4.15 (addressed herein); and Division 5 RGs are addressed in the Security Plan.
1.9S.2 Conformance with the Standard Review Plan Table 1.9S-3 addresses conformance with the March 2007 Standard Review Plan (SRP) for the site-specific portions of the facility design not included in the reference ABWR DCD, including the operational aspects of the facility. The table also addresses the SRP sections noted in the reference ABWR DCD Table 1.8-19 as the responsibility of the COL Applicant. Table 1.9S-4 addresses conformance with the March 2007 SRP for the Tier 1 and Tier 2* departures.
1.9S.3 Generic Issues RG 1.206 states that COL applicants should address applicable unresolved safety issues and medium- and high-priority generic safety issues identified in NUREG-0933 for the site-specific portions of the facility design not included in the reference ABWR DCD, including how they pertain to operational aspects of the facility. The only applicable medium- or high-priority generic issue listed in NUREG-0933, Appendix B, Rev. 21, dated June 30, 2006, is new Generic Issue 156.6.1 regarding pipe break effects on systems and components. The site-specific portions of the STP 3 & 4 design that are not included in the reference ABWR DCD meet the requirements of SRP 3.6.1, Rev. 3 and 3.6.2, Rev. 2, dated March 2007.
Table 1.9S-5 addresses generic issues identified in Table 19B of the reference ABWR DCD as the responsibility of the COL applicant.
1.9S.4 Operational Experience (Generic Communications) RG 1.206 states that COL applicants who reference a certified design should address only those generic communications applicable to the portions of their facility not included in the design certification and which have been issued after the SRP update (March 2007). Additionally, for COL applicants that include departures from the referenced certified design, the departures should address the applicable Generic Letters and Bulletins in effect/issued up to six months before the submittal date of the COL and issued after the SRP update.
Conformance with Regulatory Criteria 1.9S-1 Rev. 12
STP 3 & 4 Final Safety Analysis Report
The NRC issued no Generic Letters and Bulletins between the March 2007 update of the SRP and September 2007.
Table 1.9S-6 addresses those generic communications (Generic Letters and Bulletins) that were identified in the reference ABWR DCD Table 1.8-22 as the responsibility of the COL applicant.
Table 1.9S-1 Site-Specific Conformance with Regulatory Guides No. Title Rev.
Division 1 1.3 Assumptions Used for Evaluating the Potential Radiological Consequences 2 (6/74) of a Loss-of-Coolant Accident for Boiling Water Reactors 1.5 Assumptions Used for Evaluating the Potential Radiological Consequences 0 (3/71) of a Steamline Break Accident for Boiling Water Reactors 1.6 Independence Between Redundant Standby (Onsite) Power Sources and 0 (3/71) Between Their Distribution Systems 1.8 Personnel Selection and Training See QAPD Part IV 1.21 Measuring, Evaluating, and Reporting Radioactivity in Solid Wastes and 1 (6/74) Releases of Radioactive Materials in Liquid and Gaseous Effluents from Light-Water-Cooled Nuclear Power Plants 1.22 Periodic Testing of Protection System Actuation Functions 0 (2/72) 1.23 Meteorological Monitoring Programs for Nuclear Power Plants 1 (3/07) 1.25 Assumptions Used for Evaluating the Potential Radiological Consequences 0 (3/72) of a Fuel Handling Accident in the Fuel Handling and Storage Facility for Boiling and Pressurized Water Reactors 1.26 Quality Group Classifications and Standards for Water-, Steam-, and See QAPD Part Radioactive-Waste- Containing Components of Nuclear Power Plants IV 1.27 Ultimate Heat Sink for Nuclear Power Plants 2 (1/76) 1.28 Quality Assurance Program Requirements See QAPD Part (Design and Construction) IV 1.29 Seismic Design Classification See QAPD Part IV 1.33 Quality Assurance Program Requirements (Operations) See QAPD Part IV 1.37 Quality Assurance Requirements for Cleaning of Fluid Systems and See QAPD Part Associated IV Components of Water-Cooled Nuclear Power Plants 1.43 Control of Stainless Steel Weld Cladding of Low-Alloy Steel Components 0 (5/73) 1.53 Application of the Single-Failure Criterion to Nuclear Power Plant Protection 2 (11/03) Systems
1.9S-2 Conformance with Regulatory Criteria Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 1.9S-1 Site-Specific Conformance with Regulatory Guides (Continued) No. Title Rev. 1.54 Service Level I, II, and III Protective, Coatings Applied to Nuclear Power See QAPD Part Plants IV 1.59 Design Basis Floods for Nuclear Power Plants 2 (8/77) 1.60 Design Response Spectra for Seismic Design of Nuclear Power Plants 1 (12/73) 1.61 Damping Values for Seismic Design of Nuclear Power Plants 1 (3/07) 1.68 Initial Test Programs for Water-Cooled Nuclear Power Plants 3 (3/07) 1.75 Physical Independence of Electric Systems 3 (2/05) 1.76 Design-Basis Tornado and Tornado Missiles for Nuclear Power Plants 1 (3/07) 1.78 Evaluating the Habitability of a Nuclear Power Plant Control Room During a 1 (12/01) Postulated Hazardous Chemical Release 1.91 Evaluations of Explosions Postulated to Occur on Transportation Routes 1 (2/78) Near Nuclear Power Plants 1.92 Combining Modal Responses and Spatial Components in Seismic Response 2 (7/06) Analysis 1.96 Design of Main Steam Isolation Valve Leakage Control Systems for Boiling 1 (6/76) Water Reactor Nuclear Power Plants 1.97 Criteria for Accident Monitoring Instrumentation for Nuclear Power Plants 4 (6/06) 1.98 Assumptions Used for Evaluating the Potential Radiological Consequences 0 (3/76) of a Radioactive Offgas System Failure in a Boiling Water Reactor 1.102 Flood Protection for Nuclear Power Plants 1 (9/76) 1.105 Setpoints for Safety-Related Instrumentation 3 (12/99) 1.109 Calculation of Annual Doses to Man from Routine Releases of Reactor 1 (10/77) Effluents for the Purpose of Evaluating Compliance with 10 CFR Part 50, Appendix I 1.111 Methods for Estimating Atmospheric Transport and Dispersion of Gaseous 1 (7/77) Effluents in Routine Releases from Light-Water-Cooled Reactors 1.112 Calculation of Releases of Radioactive Materials in Gaseous and Liquid 1 (3/07) Effluents from Light-Water-Cooled Power Reactors 1.113 Estimating Aquatic Dispersion of Effluents from Accidental and Routine 1 (4/77) Reactor Releases for the Purpose of Implementing Appendix I 1.115 Protection Against Low-Trajectory Turbine Missiles 1 (7/77) 1.117 Tornado Design Classification 1 (4/78) 1.122 Development of Floor Design Response Spectra for Seismic Design of Floor- 1 (2/78) Supported Equipment or Components 1.132 Site Investigations for Foundations of Nuclear Power Plants 2 (10/03) 1.135 Normal Water Level and Discharge at Nuclear Power Plants 0 (9/77)
Conformance with Regulatory Criteria 1.9S-3 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 1.9S-1 Site-Specific Conformance with Regulatory Guides (Continued) No. Title Rev. 1.138 Laboratory Investigations of Soils and Rocks for Engineering Analysis and 2 (12/03) Design of Nuclear Power Plants 1.140 Design, Inspection, and Testing Criteria for Air Filtration and Adsorption Units 2 (6/01) of Normal Atmosphere Cleanup Systems in Light-Water-Cooled Nuclear Power Plants 1.142 Safety-Related Concrete Structures for Nuclear Power Plants (Other than 2 (11/01) Reactor Vessels and Containments) 1.143 Design Guidance for Radioactive Waste Management Systems, Structures, 2 (11/01) (RWB, and Components Installed in Light-Water-Cooled Nuclear Power Plants radwaste pipe tunnel, and liquid and solid waste management systems) 1.153 Criteria for Safety Systems 1 (6/96) 1.160 Monitoring the Effectiveness of Maintenance at Nuclear Power Plants 2 (3/97) [per NEI 07-02] 1.165 Identification and Characterization of Seismic Sources and Determination of 0 (3/97) Safe Shutdown Earthquake Ground Motion 1.182 Assessing and Managing Risk Before Maintenance Activities at Nuclear 0 (5/00) Power Plants [per NEI 07-02] 1.189 Fire Protection for Nuclear Power Plants 1 (3/07) 1.194 Atmospheric Relative Concentrations for Control Room Radiological 0 (6/03) Habitability Assessments at Nuclear Power Plants 1.198 Procedures and Criteria for Assessing Seismic Soil Liquefaction at Nuclear 0 (11/03) Power Plant Sites 1.199 Anchoring Components and Structural Supports in Concrete 0 (11/03) 1.204 Guidelines for Lightning Protection of Nuclear Power Plants 0 (11/05) 1.206 Combined License Applications for Nuclear Power Plants 0 (6/07) 1.208 A Performance-Based Approach to Define the Site-Specific Earthquake 0 (3/07) Ground Motion 1.221 Design-Basis Hurricane and Hurricane Missiles for Nuclear Power Plants 0 (10/11) Division 4 4.15 Quality Assurance for Radiological Monitoring Programs (Normal Operation) 1 (2/79) – Effluent Streams and the Environment
1.9S-4 Conformance with Regulatory Criteria Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 1.9S-1 Site-Specific Conformance with Regulatory Guides (Continued) No. Title Rev. Division 8 8.1 Radiation Symbol 0 (2/73) 8.4 Direct-Reading and Indirect-Reading Pocket Dosimeters 0 (2/73) 8.5 Criticality and Other Interior Evacuation Signals 1 (3/81) 8.6 Standard Test Procedure for Geiger-Muller Counters 0 (5/73) 8.7 Instructions for Recording and Reporting Occupational Radiation Exposure 2 (11/05) Data 8.8 Information Relevant to Ensuring that Occupational Radiation Exposures at 3 (6/78) Nuclear Power Stations Will Be as Low as Is Reasonably Achievable 8.9 Acceptable Concepts, Models, Equations, and Assumptions for a Bioassay 1 (7/93) Program 8.10 Operating Philosophy for Maintaining Occupational Radiation Exposures as 1-R (5/77) Low as Is Reasonably Achievable 8.13 Instruction Concerning Prenatal Radiation Exposure 3 (6/99) 8.15 Acceptable Programs for Respiratory Protection 1 (10/99) 8.20 Applications of Bioassay for I-125 and I-131 1 (9/79) 8.26 Applications of Bioassay for Fission and Activation Products 0 (9/80) 8.27 Radiation Protection Training for Personnel at Light-Water-Cooled Nuclear 0 (3/81) Power Plants 8.28 Audible-Alarm Dosimeters 0 (8/81) 8.29 Instruction Concerning Risks from Occupational Radiation Exposure 1 (2/96) 8.32 Criteria for Establishing a Tritium Bioassay Program 0 (7/88) 8.34 Monitoring Criteria and Methods To Calculate Occupational Radiation Doses 0 (7/92) 8.35 Planned Special Exposures 0 (6/92) 8.36 Radiation Dose to the Embryo/Fetus 0 (7/92) 8.38 Control of Access to High and Very High Radiation Areas of Nuclear Plants 1 (5/06)
Conformance with Regulatory Criteria 1.9S-5 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 1.9S-2 Conformance with Regulatory Guides Noted as “COL Applicant” in DCD
No. Title Conformance 1.16 Reporting of Operating Information Appendix A RG 1.16, Rev. 4 does not reflect current Technical Specifications, regulations. STP 3 & 4 will conform to Rev. 4 10 CFR 50.72 and 10 CFR 50.73. 1.33 Quality Assurance Program Requirements See QAPD Part IV. (Operations) 1.71 Welder Qualifications for Areas of Limited Refer to Subsection l0.3.6.3. Accessibility, Rev. 0 1.86 Termination of Operating Licenses for Nuclear Not applicable. Reactors, Rev. 0 1.90 Inservice Inspection of Prestressed Concrete Not applicable. Containment Structures with Grouted Tendons, Rev. 1 1.114 Guidance on Being Operator at the Controls of STP 3 & 4 meets the intent of this guide by a Nuclear Power Plant, Rev. 1 having sufficient operators on duty in the control room to assure visual contact with reactor controls and instrumentation during routine log rounds. 1.127 Inspection of Water-Control Structures Not applicable. Associated with Nuclear Power Plants, Rev. 1 1.134 Medical Evaluation of Licensed Personnel for Conforms. Nuclear Power Plants, Rev. 2 1.149 Nuclear Power Plant Simulation facilities for The simulator will be certified in accordance Use in Operator License Examinations, Rev. 1 with RG 1.149, Rev. 3 and ANSI/ANS 3.5- 1998.
1.9S-6 Conformance with Regulatory Criteria Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 1.9S-3 Site-Specific Conformance with Standard Review Plan No. Title Rev. Chapter 1 – Introduction and General Description of the Plant 1.0 Introduction and Interfaces 0 (3/07) Chapter 2 – Site Characteristics 2.0 Site Characteristics and Site Parameters 0 (3/07) 2.1.1 Site Location and Description 3 (3/07) 2.1.2 Exclusion Area Authority and Control 3 (3/07) 2.1.3 Population Distribution 3 (3/07) 2.2.1-2.2.2 Identification of Potential Hazards in Site Vicinity 3 (3/07) 2.2.3 Evaluation of Potential Accidents 3 (3/07) 2.3.1 Regional Climatology 3 (3/07) 2.3.2 Local Meteorology 3 (3/07) 2.3.3 Onsite Meteorological Measurements Programs 3 (3/07) 2.3.4 Short-Term Atmospheric Dispersion Estimates for Accident Releases 3 (3/07) 2.3.5 Long-Term Atmospheric Dispersion Estimates for Routine 3 (3/07) Releases 2.4.1 Hydrologic Description 3 (3/07) 2.4.2 Floods 4 (3/07) 2.4.3 Probable Maximum Flood (PMF) on Streams and Rivers 4 (3/07) 2.4.4 Potential Dam Failures 3 (3/07) 2.4.5 Probable Maximum Surge and Seiche Flooding 3 (3/07) 2.4.6 Probable Maximum Tsunami Hazards 3 (3/07) 2.4.7 Ice Effects 3 (3/07) 2.4.8 Cooling Water Canals and Reservoirs 3 (3/07) 2.4.9 Channel Diversions 3 (3/07) 2.4.10 Flooding Protection Requirements 3 (3/07) 2.4.11 Low Water Considerations 3 (3/07) 2.4.12 Groundwater 3 (3/07) 2.4.13 Accidental Releases of Radioactive Liquid Effluents in Ground and 3 (3/07) Surface Waters 2.4.14 Technical Specifications and Emergency Operation Requirements 3 (3/07) 2.5.1 Basic Geologic and Seismic Information 4 (3/07) 2.5.2 Vibratory Ground Motion 4 (3/07) 2.5.3 Surface Faulting 4 (3/07)
Conformance with Regulatory Criteria 1.9S-7 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 1.9S-3 Site-Specific Conformance with Standard Review Plan (Continued) No. Title Rev. 2.5.4 Stability of Subsurface Materials and Foundations 3 (3/07) 2.5.5 Stability of Slopes 3 (3/07) Chapter 3 – Design of Structures, Components, Equipment, and Systems 3.2.1 Seismic Classification 2 (3/07) 3.2.2 System Quality Group Classification 2 (3/07) 3.3.1 Wind Loadings 3 (3/070 3.3.2 Tornado Loadings 3 (3/07) 3.4.2 Analysis Procedures 3 (3/07) 3.5.1.3 Turbine Missiles 3 (3/07) 3.5.1.4 Missiles Generated by Tornadoes and Extreme Winds 3 (3/07) 3.5.3 Barrier Design Procedures 3 (3/07) 3.7.1 Seismic Design Parameters 3 (3/07) 3.7.2 Seismic System Analysis 3 (3/07) 3.8.4 Other Seismic Category I Structures 2 (3/07) Appendix B 2 (3/07) Appendix C 2 (3/07) 3.8.5 Foundations 2 (3/07) Chapter 8 – Electrical Power 8.1 Electric Power – Introduction 3 (3/07) 8.2 Offsite Power system 4 (3/07) Appendix A 4 (3/07) Chapter 9 – Auxiliary Systems 9.2.1 Station Service Water System 5 (3/07) 9.2.2 Reactor Auxiliary Cooling Water Systems 4 (3/07) 9.2.4 Potable and Sanitary Water Systems 3 (3/07) 9.2.5 Ultimate Heat Sink 3 (3/07) 9.3.1 Compressed Air System 2 (3/07) 9.3.3 Equipment and Floor Drainage System 3 (3/07) 9.5.1 Fire Protection Program 5 (3/07) Appendix A 5 (3/07) 9.5.2 Communications Systems 3 (3/07)
1.9S-8 Conformance with Regulatory Criteria Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 1.9S-3 Site-Specific Conformance with Standard Review Plan (Continued) No. Title Rev. Chapter 10 – Steam and Power Conversion System 10.4.5 Circulating Water System 3 (3/07) Chapter 11 – Radioactive Waste Management 11.5 Process and Effluent Radiological Monitoring Instrumentation and 3 (7/81) Sampling Systems BTP 11-6 Postulated Radioactive Releases due to Liquid-Containing Tank 3 (3/07) Failures Chapter 12 – Radiation Protection 12.5 Operational Radiation Protection Program 3 (3/07) Chapter 13 – Conduct of Operations 13.1.1 Management and Technical Support Organization 5 (3/07) 13.1.2-13.1.3 Operating Organization 6 (3/07) 13.2.1 Reactor Operator Requalification Program; Reactor Operator Training 3 (3/07) 13.2.2 Non-Licensed Plant Staff Training 3 (3/07) 13.3 Emergency Planning 3 (3/07) 13.4 Operational Programs 3 (3/07) 13.5.1 Administrative Procedures 0 (7/81) 13.5.1.1 Administrative Procedures - General 0 (3/07) 13.5.1.2 Administrative Procedures – Initial Test Program 0 (6/96) 13.5.2.1 Operating and Emergency Operating Procedures 2 (3/07) Appendix A 2 (3/07) 13.5.2.2 Maintenance and Other Operating Procedures 0 (4/96) DRAFT 13.6 Physical Security 3 (3/07) 13.6.1 Physical Security – Combined License Review Responsibilities 0 (3/07) Chapter 17 – Quality Assurance 17.5 Quality Assurance Program Description - Design Certification, Early Site 0 (3/07) Permit and New License Applicants
Conformance with Regulatory Criteria 1.9S-9 Rev. 12
STP 3 & 4 Final Safety Analysis Report licable SRP section Conformance with Applicable SRP/ with Applicable Conformance JustificationDifferences for Conforms with applicable SRP sections with applicable Conforms Conforms with applicable SRP sections with applicable Conforms Conforms with applicable SRP sections with applicable Conforms Applicable SRP Sections 5.3.1 5.3.3 1.0 App 7.0-A 7.1 7.2 7.3 7.6 7.7 1.0 3.4.1 5.2.5 7.1 7.1 Table App 7.1-A 7.2 7.3 7.5 11.5 13.3 15.2.1-15.2.5 16.0 1 14.3app Conforms with Tier 1 Section 2.1 Section 1 Tier 5.3 Section 2 Tier Tier 1 Section 2.2 Section 1 Tier 2.15 Section 1 Tier 7.2 Section 2 Tier 7.6 Section 2 Tier 7.7 Section 2 Tier 10.1 Section 2 Tier 2 Section 16.3.3.1.1Tier 16B.3.3.1.1 Section 2 Tier Tier 1 Section 2.3 Section 1 Tier 2.7 Section 1 Tier 1.2 Section 2 Tier 1A Appendix 2 Tier 3.4 Section 2 Tier 5.2 Section 2 Tier 7.1 Section 2 Tier 7.2 Section 2 Tier 7.3 Section 2 Tier 7.5 Section 2 Tier 15.2 Section 2 Tier 2 Section 16.3.3.1.1Tier 2 Section 16.3.3.6.1Tier 16B.3.3.1.1 Section 2 Tier 16B.3.3.6.1 Section 2 Tier Table 1.9S-4 Conformance of Tier 1 and Tier 2* Departures with the SRP with the 2* Departures and Tier 1 of Tier Conformance 1.9S-4 Table Definition of Definition As-Built 1. Section 1 Tier RIP Motor Casing Casing RIP Motor Cladding Control System Changes Hi Rad MSIV Closure Departure Departure Number Subject COLA Sections Affected STD DEP 1.1-1 T1 STD DEP 2.1-2 T1 STD DEP 2.2-1 T1 STD DEP 2.3-1 T1
1.9S-10 Conformance with Regulatory Criteria Rev. 12
STP 3 & 4 Final Safety Analysis Report Conformance with Applicable SRP/ with Applicable Conformance JustificationDifferences for SRP sections with applicable Conforms Applicable SRP Sections 3.2.1 3.2.2 5.4 5.4.7 6.3 6.6 7.3 7.4 9.1.1 9.1.2 9.1.3 9.1.4 9.1.5 13.4 19.1 19.2 Affected COLA Sections Affected Tier 1 Section 2.4 Section 1 Tier 2.6 Section 1 Tier 1AA Appendix 2 Tier 3.1 Section 2 Tier 3.9 Section 2 Tier 3MA Appendix 2 Tier 5.4 Section 2 Tier 6.3 Section 2 Tier 6.6 Section 2 Tier 7.3 Section 2 Tier 7.4 Section 2 Tier 9.1 Section 2 Tier 19L Appendix 2 Tier 19Q Appendix 2 Tier Table 1.9S-4 Conformance of Tier 1 and Tier 2* Departures with the SRP (Continued) Departures 2* Tier 1 and of Tier 1.9S-4 Conformance Table RHR Spent Fuel RHR Spent Cooling Pool Departure Departure NumberSTD DEP Subject 2.4-1 T1
Conformance with Regulatory Criteria 1.9S-11 Rev. 12
STP 3 & 4 Final Safety Analysis Report Conformance with Applicable SRP/ with Applicable Conformance JustificationDifferences for SRP sections with applicable Conforms Applicable SRP Sections 3.2.2 3.6.2 3.6.3 3.8.3 3.11 5.2.2 5.2.3 5.2.4 5.2.5 6.2.1.1C 6.2.1.2 6.2.1.3 6.2.1.4 6.2.2 6.2.3 6.2.4 6.5.2 6.6 9.2.2 9.2.3 10.2 16.0 Affected COLA Sections Affected Tier 1 Section 2.4 Section 1 Tier 5.2 Section 2 Tier 6.2 Section 2 Tier 7.3 Section 2 Tier 8.1 Section 2 Tier 8.3 Section 2 Tier 10.2 Section 2 Tier 19L Appendix 2 Tier 2 Section 16.3.3.1.1Tier 2 Section 16.3.3.1.4Tier 16B.3.3.1.1 Section 2 Tier 16B.3.3.1.4 Section 2 Tier Table 1.9S-4 Conformance of Tier 1 and Tier 2* Departures with the SRP (Continued) Departures 2* Tier 1 and of Tier 1.9S-4 Conformance Table FW Line Break Mitigation Departure Departure NumberSTD DEP Subject 2.4-2 T1
1.9S-12 Conformance with Regulatory Criteria Rev. 12
STP 3 & 4 Final Safety Analysis Report Conformance with Applicable SRP/ with Applicable Conformance JustificationDifferences for SRP sections with applicable Conforms Applicable SRP Sections 3.2.2 5.4 5.4.6 5.4.7 6.2.1.2 6.2.1.3 6.2.1.4 6.2.1.5 6.2.2 6.2.4 7.3 14.2 16.0 16.1 19.1 19.2 6.2 SRP sections Conforms with applicable Affected COLA Sections Affected Tier 2 Appendix 1A Appendix 2 Tier 3.2 Section 2 Tier 3.9 Section 2 Tier 3B Appendix 2 Tier 3MA Appendix 2 Tier 5.4 Section 2 Tier 6.2 Section 2 Tier 7.3 Section 2 Tier 14.2 Section 2 Tier 2 Section 16.3.3.1.1Tier 2 Section 16.3.3.1.4Tier 16B.3.3.1.1 Section 2 Tier 16B.3.3.1.4 Section 2 Tier 19.3 Section 2 Tier 19.9 Section 2 Tier 19.11 Section 2 Tier 19.13 Section 2 Tier 19K Appendix 2 Tier 19M Appendix 2 Tier Tier 1 Section 2.4 Section 1 Tier 5.4 Section 2 Tier 6.2 Section 2 Tier 6.3 Section 2 Tier 6C Appendix 2 Tier 14.2 Section 2 Tier Table 1.9S-4 Conformance of Tier 1 and Tier 2* Departures with the SRP (Continued) Departures 2* Tier 1 and of Tier 1.9S-4 Conformance Table RCIC Pump 1 Section 2.4 Tier RHR, HPCF, and RCIC RHR, HPCF, NPSH Pump Turbine Departure Departure NumberSTD DEP Subject 2.4-3 T1 STD DEP 2.4-4 T1
Conformance with Regulatory Criteria 1.9S-13 Rev. 12
STP 3 & 4 Final Safety Analysis Report plicable SRP section Conformance with Applicable SRP/ with Applicable Conformance JustificationDifferences for SRP Sections with applicable Conforms Conforms with applicable SRP sections with applicable Conforms Applicable SRP Sections 9.1.1 9.1.2 10.4.714.3.6 SRP sections with applicable Conforms App 7.1-C Conformsap with Affected COLA Sections Affected Tier 1 Section 2.5 Section 1 Tier 1.2 Section 2 Tier 3.1 Section 2 Tier 9.1 Section 2 Tier 12.3 Section 2 Tier 16.4 Section 2 Tier Tier 1 Section 1 Tier 2.10 2.12 Section 1 Tier 14.3 Tier 1 Section 2.12 Section 1 Tier 8.1 Section 2 Tier 8.3 Section 2 Tier Table 1.9S-4 Conformance of Tier 1 and Tier 2* Departures with the SRP (Continued) Departures 2* Tier 1 and of Tier 1.9S-4 Conformance Table New Fuel Storage Racks Addition of Addition Condensate Booster Pumps Breaker/Fuse Coordination I&C Power Division Departure Departure NumberSTP DEP Subject 2.5-1 T1 STD DEP 2.10-1 T1 STD DEP 2.12-1 T1 STD DEP 2.12-2 T1
1.9S-14 Conformance with Regulatory Criteria Rev. 12
STP 3 & 4 Final Safety Analysis Report Conformance with Applicable SRP/ with Applicable Conformance JustificationDifferences for SRP sections with applicable Conforms Applicable SRP Sections 3.2.2 5.4 5.4.6 5.4.7 6.2.2 6.5.2 6.5.3 6.5.5 7.1 7.3 7.4 7.5 7.6 16.0 16.1 Affected COLA Sections Affected Tier 1 Section 2.2 Section 1 Tier 2.3 Section 1 Tier 2.4 Section 1 Tier 2.7 Section 1 Tier 2.11 Section 1 Tier 2.14 Section 1 Tier 2.15 Section 1 Tier 1.2 Section 2 Tier 1A Appendix 2 Tier 1AA Appendix 2 Tier 3.2 Section 2 Tier 3.9 Section 2 Tier 3I Appendix 2 Tier 3MA Appendix 2 Tier 5.2 Section 2 Tier 5.4 Section 2 Tier 6.2 Section 2 Tier 6.5 Section 2 Tier 6.6 Section 2 Tier 7.1 Section 2 Tier 7.3 Section 2 Tier 7.4 Section 2 Tier 7.5 Section 2 Tier 7.6 Section 2 Tier 9.2 Section 2 Tier 9.4 Section 2 Tier 9A Appendix 2 Tier 14.2 Section 2 Tier 15A Appendix 2 Tier Table 1.9S-4 Conformance of Tier 1 and Tier 2* Departures with the SRP (Continued) Departures 2* Tier 1 and of Tier 1.9S-4 Conformance Table Hydrogen Recombiner Elimination Departure Departure NumberSTD DEP Subject 2.14-1 T1
Conformance with Regulatory Criteria 1.9S-15 Rev. 12
STP 3 & 4 Final Safety Analysis Report Conformance with Applicable SRP/ with Applicable Conformance JustificationDifferences for Applicable SRP Sections Affected COLA Sections Affected Tier 2 Section 16.3.3.6.1Tier 2 Section 16.3.3.6.2Tier 2 Section 16.3.6.3.1Tier 2 Section 16.3.6.3.2Tier 16.5.0 Section 2 Tier 16B.3.3.6.1 Section 2 Tier 16B.3.3.6.2 Section 2 Tier 16B.3.6.3.1 Section 2 Tier 16B.3.6.3.2 Section 2 Tier 18A Appendix 2 Tier 18B Appendix 2 Tier 18F Appendix 2 Tier 18H Appendix 2 Tier 19A Appendix 2 Tier Table 1.9S-4 Conformance of Tier 1 and Tier 2* Departures with the SRP (Continued) Departures 2* Tier 1 and of Tier 1.9S-4 Conformance Table Hydrogen Recombiner Elimination (continued) Departure Departure NumberSTD DEP Subject 2.14-1 T1 (continued)
1.9S-16 Conformance with Regulatory Criteria Rev. 12
STP 3 & 4 Final Safety Analysis Report Conformance with Applicable SRP/ with Applicable Conformance JustificationDifferences for SRP sections with applicable Conforms Conforms with applicable SRP sections with applicable Conforms Applicable SRP Sections 2.0 2.4.13 2.5.4 3.2.1 3.2.2 3.3.1 3.3.2 3.4.1 3.7.1 3.7.2 3.7.3 3.8.3 3.8.4 11.4 12.2 14.3 15.7.3 15.7.4 15.7.5 19.0 9.4.1 9.4.3 9.4.4 Affected COLA Sections Affected Tier 1 Section 2.15 Section 1 Tier 2.0 Section 2 Tier 2.4S.13 Section 2 Tier 2.5S.4 Section 2 Tier 3.1 Section 2 Tier 3.2 Section 2 Tier 3.3 Section 2 Tier 3.4 Section 2 Tier 3.7 Section 2 Tier 3.8 Section 2 Tier 3C Appendix 2 Tier 3H Appendix 2 Tier 11.4 Section 2 Tier 12.2 Section 2 Tier 14.3 Section 2 Tier 15.7 Section 2 Tier 19.4 Section 2 Tier 19H Appendix 2 Tier 21.0 Section 2 Tier 21.1 Section 2 Tier Tier 1 Section 2.15 Section 1 Tier 9.4 Section 2 Tier Table 1.9S-4 Conformance of Tier 1 and Tier 2* Departures with the SRP (Continued) Departures 2* Tier 1 and of Tier 1.9S-4 Conformance Table Radwaste Building Seismic Substructure Classification RBSRDG HVAC Departure Departure NumberSTD DEP Subject 2.15-1 T1 STD DEP 2.15-2 T1
Conformance with Regulatory Criteria 1.9S-17 Rev. 12
STP 3 & 4 Final Safety Analysis Report Conformance with Applicable SRP/ with Applicable Conformance JustificationDifferences for SRP sections with applicable Conforms Applicable SRP Sections 3.2.1 3.2.2 6.2.4 App 7.0-A 7.1 7.2 7.3 7.4 7.6 7.7 7.9 10.3 10.4.5 10.4.7 11.5 12.3-12.4 Affected COLA Sections Affected Tier 1 Section 2.2 Section 1 Tier 2.7 Section 1 Tier 3.4 Section 1 Tier 1.2 Section 2 Tier 3.2 Section 2 Tier 6.2 Section 2 Tier 7.1 Section 2 Tier 7.2 Section 2 Tier 7.3 Section 2 Tier 7.4 Section 2 Tier 7.6 Section 2 Tier 7.7 Section 2 Tier 7A Appendix 2 Tier 7C Appendix 2 Tier 10.1 Section 2 Tier 10.4 Section 2 Tier Table 1.9S-4 Conformance of Tier 1 and Tier 2* Departures with the SRP (Continued) Departures 2* Tier 1 and of Tier 1.9S-4 Conformance Table Safety-Related I&C Architecture Departure Departure NumberSTD DEP Subject 3.4-1 T1
1.9S-18 Conformance with Regulatory Criteria Rev. 12
STP 3 & 4 Final Safety Analysis Report Conformance with Applicable SRP/ with Applicable Conformance JustificationDifferences for Applicable SRP Sections 14.2 15.8 16.0 18.0 19.0 Affected COLA Sections Affected Tier 2 Section 11.5 Section 2 Tier 12.3 Section 2 Tier 14.2 Section 2 Tier 15.0 Section 2 Tier 15.1S Section 2 Tier 15B Appendix 2 Tier 15E Appendix 2 Tier 16.1.0 Section 2 Tier 16.5.0 Section 2 Tier 2 Section 16.3.3.1.4Tier 2 Section 16.3.3.3.1Tier 16B.3.3.1.1 Section 2 Tier 16B.3.3.1.4 Section 2 Tier 16B.3.3.3.1 Section 2 Tier 16B.3.3.4.1 Section 2 Tier 16B.3.3.5.1 Section 2 Tier 16B.3.3.6.1 Section 2 Tier 16B.3.3.6.2 Section 2 Tier 16B.3.8.4 Section 2 Tier 18.4 Section 2 Tier 18.6 Section 2 Tier 18.8 Section 2 Tier 18C Appendix 2 Tier 18E Appendix 2 Tier 19.3 Section 2 Tier 19.9 Section 2 Tier 19.11 Section 2 Tier 19K Appendix 2 Tier 19L Appendix 2 Tier 19N Appendix 2 Tier 19Q Appendix 2 Tier Table 1.9S-4 Conformance of Tier 1 and Tier 2* Departures with the SRP (Continued) Departures 2* Tier 1 and of Tier 1.9S-4 Conformance Table Safety-Related I&C Architecture (continued) Departure Departure NumberSTD DEP Subject 3.4-1 T1 (Continued)
Conformance with Regulatory Criteria 1.9S-19 Rev. 12
STP 3 & 4 Final Safety Analysis Report Conformance with Applicable SRP/ with Applicable Conformance JustificationDifferences for SRP sections with applicable Conforms FSER 19.1.3.3.4 Conforms with Applicable SRP Sections 2.0 2.2.1-2.2.2 2.4.1 2.4.2 2.4.3 2.4.4 2.4.10 3.4.1 3.4.2 6.4 6.5.1 9.2.1 9.2.5 9.4.1 9.4.2 9.4.3 9.4.4 9.4.5 Affected COLA Sections Affected Tier 2 Section 2.2 Section 2 Tier 3.1 Section 2 Tier 3.4 Section 2 Tier 3H Appendix 2 Tier 9.4 Section 2 Tier 19.3 Section 2 Tier 19.9 Section 2 Tier 19.11 Section 2 Tier 19.13 Section 2 Tier 19K Appendix 2 Tier 19Q Appendix 2 Tier 19R Appendix 2 Tier Table 1.9S-4 Conformance of Tier 1 and Tier 2* Departures with the SRP (Continued) Departures 2* Tier 1 and of Tier 1.9S-4 Conformance Table Site Parameters 5.0 Section 1 Tier Departure Departure NumberSTP DEP Subject 5.0-1 T1
1.9S-20 Conformance with Regulatory Criteria Rev. 12
STP 3 & 4 Final Safety Analysis Report Conformance with Applicable SRP/ with Applicable Conformance JustificationDifferences for SRP sections with applicable Conforms Conforms with applicable SRP sections with applicable Conforms Applicable SRP Sections 1.8 3.2.1 3.2.2 3.8.1 3.8.3 3.8.4 3.8.5 3.9.2 3.9.6 3.12 5.2.3 5.2.4 5.2.5 5.3.1 5.3.2 19.0 Affected COLA Sections Affected Tier 2 Section 1.8 Section 2 Tier 3.9 Section 2 Tier 5.2 Section 2 Tier 7A Appendix 2 Tier Tier 2, Appendix 3B Appendix 2, Tier 6.2.1.1.C Table 1.9S-4 Conformance of Tier 1 and Tier 2* Departures with the SRP (Continued) Departures 2* Tier 1 and of Tier 1.9S-4 Conformance Table Codes, Standards, Codes, RGs and Revised Pool SwellRevised Pool Analysis Departure Departure NumberSTD DEP Subject 1.8-1 STD DEP 3B-2 note (see below) Note: STD DEP 3B-2 does not impact COLA Tier 1 or Tier 2*, but does require NRC approval 2*, require but does 1 or Tier COLA Tier impact Note: STD not DEP 3B-2 does
Conformance with Regulatory Criteria 1.9S-21 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 1.9S-5 COL Applicant Resolution of ABWR DCD Appendix 19B Issues
Title Resolution
Generic Issues A-1 Water Hammer Section 19B.2.2 A-36 Control of Heavy Loads near Spent Fuel Pool Section 19B.2.12 A-47 Safety Implications of Control Systems Operating procedures and operator training will ensure that the operators can mitigate reactor vessel overfill events that may occur via the condensate booster pumps during reduced pressure operation of the system. Section 19B.2.17 C-1 Assurance of Continuous Long-Term Capability of 19B.2.27 Hermetic Seals on Instrumentation and Electrical Equipment C-17 Interim Acceptance Criteria for Solidification Agents for Section 19B.2.29; Radioactive Solid Wastes 10 CFR 61
New Generic Issues 51 Proposed Requirements for Improving the Reliability of Implementation of a baseline Open Cycle Service Water Systems fouling program issued to licensees in GL 89-13; Section 19B.2.35 75 Generic Implications of ATWS Events at the Salem Sections 13.4S, 13.5, and Nuclear Plant 19B.2.38 105 Interfacing Systems LOCA at BWRs No longer listed in NUREG- 0933. Therefore, not applicable to future reactor plants.
1.9S-22 Conformance with Regulatory Criteria Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 1.9S-5 COL Applicant Resolution of ABWR DCD Appendix 19B Issues (Continued) Title Resolution 145 Actions to Reduce Common Cause Failures No longer listed in NUREG- 0933. Therefore, not applicable to future reactor plants. 153 Loss of Essential Service Water in LWRs No longer listed in NUREG- 0933. Therefore, not applicable to future reactor plants.
Issues Resolved with no New Requirements A-29 Nuclear Power Plant Design for Reduction of No longer listed in NUREG- Vulnerability to Industrial Sabotage 0933. Therefore, not applicable to future reactor plants. 120 On-Line Testability of Protection Systems No longer listed in NUREG- 0933. Therefore, not applicable to future reactor plants. 151 Reliability of Anticipated Transient without Scram No longer listed in NUREG- Recirculation Pump Trip in BWRs 0933. Therefore, not applicable to future reactor plants.
TMI Issues I.A.1.1 Shift Technical Advisor Section 13.1 I.A.1.2 Shift Supervisor Administrative Duties Section 13.1 I.A.1.3 Shift Manning Technical Specifications I.A.2.1(1) Qualifications - Experience Section 13.2 I.A.2.1(2) Training Section 13.2 I.A.2.1(3) Facility Certification of Competence and Fitness of Section 13.2 Applicants for Operator and Senior Operator
Conformance with Regulatory Criteria 1.9S-23 Rev. 12
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Table 1.9S-5 COL Applicant Resolution of ABWR DCD Appendix 19B Issues (Continued) Title Resolution I.A.2.3 Administration of Training Programs Section 13.2 I.A.2.6(1) Revise Regulatory Guide 1.8 NRC action. Not applicable. I.A.3.1 Revise Scope of Criteria for Licensing Examinations NRC action. Not applicable. I.A.4.1(2) Interim Changes in Training Simulators STP 3 & 4 will conform with RG 1.149 and will have an onsite simulator I.C.1(1) Small Break LOCAs Section 13.5 I.C.1(2) Inadequate Core Cooling Section 13.5 I.C.2 Shift and Relief Turnover Procedures Section 13.5 I.C.3 Shift Supervisor Responsibilities Section 13.1; Conduct of Operations I.C.4 Control Room Access Conduct of Operations Procedure I.C.6 Procedures for Verification of Correct Performance of Conduct of Operations Operating Activities Procedure I.C.7 NSSS Vendor Review of Procedures Applicable to W and CE only. I.C.8 Pilot – Monitoring of Selected Emergency Procedures for Historical issue. No longer Near-Term Operating License Applicants applicable. II.B.1 Reactor Coolant System Vents Sections 1A.2.5 and 13.5 II.B.4 Training for Mitigating Core Damage Section 13.2 II.E.6.1 Test Adequacy Study Section 19B.2.68
1.9S-24 Conformance with Regulatory Criteria Rev. 12
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Table 1.9S-5 COL Applicant Resolution of ABWR DCD Appendix 19B Issues (Continued) Title Resolution II.J.4.1 Revise Deficiency Reporting Requirements NRC action. Not applicable. II.K.3(15) Modify Break Detection Logic to Prevent Spurious Sections 1A.2.23 and 14.2 Isolation of HPCI and RCIC Systems III.A.1.1(1) Implement Action Plan Requirements for Promptly NRC action. Not applicable. Improving Licensee Emergency Preparedness III.A.2.1(1) Publish Proposed Amendments to the Rules NRC action. Not applicable. III.A.2.1(2) Conduct Public Regional Meetings No longer listed in NUREG- 0933. Therefore, not applicable to future reactor plants. III.A.2.1(3) Prepare Final Commission Paper Recommending No longer listed in NUREG- Adoption of Rules 0933. Therefore, not applicable to future reactor plants. III.A.2.1(4) Revise Inspection Program to Cover Upgraded NRC action. Not applicable. Requirements
III.A.2.2 Development of Guidance and Criteria NRC action. Not applicable. III.A.3.3(1) Install Direct Dedicated Telephone Lines STP 3 & 4 will use direct lines installed by STP 1 & 2. III.A.3.3(2) Obtain Dedicated, Short-Range Radio Communication NRC action. Not applicable. Systems
Conformance with Regulatory Criteria 1.9S-25 Rev. 12 STP 3 & 4 Final Safety Analysis Report
Table 1.9S-6 COL Applicant Resolution of Generic Communications Issues
No. Title Comment Generic Letters 80-110 Periodic Updating of Final Safety Analysis STP 3 & 4 will comply with Reports (FSARs) 10 CFR 50.71(e) 81-04 Emergency Procedures and Training for Station Refer to Sections 13.2 and 13.5. Blackout Events 81-38 Storage of Low-Level Radioactive Wastes at No longer applicable. Power Reactor Sites 82-21 Technical Specifications for Fire Protection STP 3 & 4 will comply with Audits 10 CFR 50 App R. 82-39 Problems with the Submittals of 10CFR73.21 No longer applicable. Safeguards Information Licensing Review 83-05 Safety Evaluation of “Emergency Procedure No longer applicable. Guidelines,” Rev 2, NEDO-24932, June 1982 83-07 Nuclear Waste Policy Act of 1982 STP 3 & 4 will negotiate a new contract with DOE for Spent Fuel prior to obtaining a COL. 83-33 NRC Position on Certain Requirements of STP 3 & 4 will comply with Appendix R to 10 CFR 50 10 CFR 50 App R. 87-06 Periodic Verification of Leak Tight Integrity of Periodic testing of pressure isolation valves Pressure Isolation Valves is assured by the ABWR DCD and the ISI and IST programs. 88-18 Plant Record Storage on Optical Disks Refer to Section 17.5S; Quality Assurance Program Description, Section 17.2
1.9S-26 Conformance with Regulatory Criteria Rev. 12 STP 3 & 4 Final Safety Analysis Report
Table 1.9S-6 COL Applicant Resolution of Generic Communications Issues (Continued) No. Title Comment 89-01 Implementation of programmatic Controls for Refer to Section 13.4S. Radiological Effluent Technical Specifications in the Administrative Controls Section of the Technical Specifications and the Relocation of Procedural Details of RETS to the Offsite Dose Calculation Manual or the Process Control Program 89-02 Actions to Improve the Detection of Counterfeit Refer to Section 17.5S and the Quality and Fraudulently Marketed Products Assurance Program Description 89-04 Guidance on Developing Acceptable In-service Refer to Section 13.4S. Testing Program 89-10 Safety-Related Motor-Operated Valve Testing Refer to Section 13.4S. and Surveillance 89-13 Service Water System Problems Affecting Refer to section 9.2.15 Safety-Related Equipment 89-15 Emergency Response Data System Refer to the Security Plan. 91-03 Reporting of Safeguards Events Refer to the Security Plan. 91-10 Explosive Searches at Protected Area Portals Refer to the Security Plan. 91-16 Licensed Operators’ and Other Nuclear Facility Refer to Section 13.7. Personnel Fitness for Duty IE Bulletins 80-05 Vacuum Condition Resulting in Damage to Not applicable to BWRs. Chemical and Volume Control System (CVCS) Holdup Tanks
Conformance with Regulatory Criteria 1.9S-27 Rev. 12 STP 3 & 4 Final Safety Analysis Report
Table 1.9S-6 COL Applicant Resolution of Generic Communications Issues (Continued) No. Title Comment 80-08 Containment Lines Penetration Welds The primary piping containment penetration flued head-to-outer sleeve-welds will be radiographed in accordance with ASME B&PV Code requirements. 80-10 Non-Radioactive System – Potential for Not applicable. Information only for CP Unmonitored Release plants. 80-12 Decay Heat Removal System Operability Not applicable. For PWRs only. 80-21 Valve Yokes Supplied by Mole Historical issue. No longer applicable. 80-22 Automatic Industries, Model 200-500-008 Historical issue. No longer applicable. Sealed Source Connectors 81-02, Failure of Gate Type Valves to Close Against Historical issue. No longer applicable. Supp 1 Differential Pressure 81-03 Flow Blockage of Cooling Water to Safety STP 3 & 4 will have a program similar to the System (bu Corbicula SP. [Asiatic Clam] and program used by STP 1 & 2 Mytilus SP. [Mussel]) 82-04 Deficiencies in Primary Containment Electrical Procurement QA program will preclude this Penetration Assemblies issue in the future. 83-06 Non-Conforming Materials Supplied by Tube- Procurement QA program will preclude this Line Corp. issue in the future. 85-03, Motor-Operated Valve Common Mode Failure Superseded by GL 89-10. Refer to Section Supp 1 During Plant Transients Due to Improper Switch 13.4S. Settings 87-02, Fastener Testing to Determine Conformance Refer to Section 3.13S. Supp 1, with Applicable Material Specifications Supp 2
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1.10S Impacts of Construction 1.10S.1 Introduction An assessment of the potential impacts of the construction of STP 3 & 4 on structures, systems, and components (SSCs) important to safety for STP 1 & 2 was performed in accordance with 10 CFR 52.79(a)(31). In addition, an assessment of potential impacts of construction of STP 4 on STP 3 when Unit 3 is operational was also performed.
These assessments involved several sequential steps:
Identification of potential construction activity hazards
Identification of SSCs important to safety and limiting conditions for operation (LCOs)
Identification of potentially impacted SSCs and LCOs
Identification of applicable managerial and administrative controls
1.10S.2 Potential Construction Activity Hazards The STP 3 & 4 units will be located on the existing STP site in an area generally west and north of the two operating units, STP 1 & 2, as shown in Figure 1.10S-1. The power blocks for the two pairs of units have a minimum separation of approximately 800 feet at their closest point while the centroids for the two power block pairs are separated by approximately 2700 feet.
Construction activities include site exploration, grading, clearing, and installation of drainage and erosion-control measures; boring, drilling, dredging, demolition, and excavating; storage and warehousing of equipment; and construction, erection, and fabrication of new facilities. Construction impacts on security controls are discussed in COLA Part 8.
Based on the assessments discussed above, STP 3 & 4 construction activities and their representative hazards are shown in Table 1.10S-1.
1.10S.3 Impacted SSCs and LCOs The construction activities described above were reviewed for possible impact to SSCs important to safety.
STP 1 & 2 SSCs important to safety are described in Chapter 3 of the STP 1&2 Updated Final Safety Analysis Report (UFSAR)
STP 3 SSCs important to safety are described in Chapter 3 of the STP 3 & 4 Final Safety Analysis Report and the reference ABWR DCD
Limiting conditions of operation for STP 1 & 2 are located in the STP 1 & 2 Technical Specifications
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As indicated in Chapter 16, the limiting conditions of operation for STP 3 are located in Part 4 of the COLA
This assessment identified the SSCs that could reasonably be expected to be impacted by construction activities unless administrative and managerial controls are established at the site. The results of the assessment are presented in Table 1.10S-2.
1.10S.4 Managerial and Administrative Controls Specific managerial and administrative controls have been identified in Table 1.10S-3 to eliminate or mitigate construction hazards that could impact SSCs important to safety. These managerial controls are considered by NINA and STPNOC to provide reasonable assurance of protecting the identified SSCs from construction hazards. In addition, these controls ensure that any associated LCOs specified in the applicable Unit's Technical Specifications are not exceeded as a result of construction activities based on the following discussion.
The majority of the SSCs important to safety are contained and protected within safety- related structures. The managerial controls established will protect these internal SSCs from postulated construction hazards by maintaining the integrity and design basis of the safety-related structures and foundations. Heavy load drop controls, crane boom failure standoff requirements, groundwater depression monitoring, ground vibration controls and construction generated missile(s) control are examples of managerial controls that would provide this reasonable assurance.
Other managerial controls will reasonably ensure that offsite power is not disrupted, hazardous materials and gasses are controlled, cooling water supplies are protected, instrumentation is protected from vibrations, and the SSCs are protected from site excavation issues. These managerial controls prevent or mitigate external construction impacts that could affect these SSCs. These controls also prevent or mitigate unnecessary challenges to safety systems caused by plant construction hazards, such as disruption of offsite transmission lines or impact to plant cooling water supplies. Onsite construction activities with potential safety significance to the operating units will also be addressed in accordance with established NINA processes.
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Table 1.10S-1 Potential Hazards from Construction Activities Construction Activity Hazard Potential Impact Site Exploration, Grading, Clearing, Overhead Power Lines Installation of Drainage and Erosion Transmission Towers Control Measures Underground Conduits, Piping, Tunnels, etc. Site Access and Egress Drainage Facilities and Structures Onsite Transportation Routes Slope Stability Soil Erosion and Local Flooding Construction-Generated Dust and Equipment Exhausts Encroachment on Plant Control Boundaries Encroachment on Structures and Facilities Boring, Drilling, Pile Driving, Underground Conduits, Piping, Tunnels Dredging, Demolition, Excavation Foundation Integrity Structural Integrity Slope Stability Erosion and Turbidity Control Groundwater and Groundwater Monitoring Facilities Dewatering Structures, Systems and Components Adjacent or Nearby Structures, Systems and Components Vibratory Ground Motion Equipment Movement, Material Overhead Power Lines Delivery, Vehicle Traffic Transmission Towers Underground Conduits, Piping, Tunnels, etc. Crane Load Drops Crane or Crane Boom Failures Vehicle Accidents Rail Car Derailments Equipment Delivery and Heavy Equipment Delivery Equipment and Material Laydown, Releases of Stored Flammable, Hazardous or Toxic Materials Storage, Warehousing Wind-Generated, Construction-Related Debris and Missiles
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Table 1.10S-1 Potential Hazards from Construction Activities (Continued) Construction Activity Hazard Potential Impact General Construction, Erection, Physical Integrity of Structures, Systems and Components Fabrication Adjacent or Nearby Structures, Systems and Components Instrumentation and Control Systems and Components Electrical Systems and Components Cooling Water Systems and Components Decay Heat Removal Structures, Systems and Components Radioactive Waste Release Points and Parameters Abandonment of Structures, Systems or Components Relocation of Structures, Systems or Components Removal of Structures, Systems or Components Shared System(s) Tie-ins and Instrumentation and Control Systems and Components Connection(s) Electrical Systems and Components Water Systems and Components Equipment and Material Laydown, Flooding Design Basis/Flood Protection Measures for STP Units Storage, Warehousing 1 & 2 General Construction, Erection, Flooding Design Basis/Flood Protection Measures for STP Units Fabrication 1 & 2
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Table 1.10S-2 Hazards During Construction Activies Potential Impact Hazard Impacted SSCs Impact on Overhead Power Lines Offsite Power System Impact on Transmission Towers Offsite Power Systems Impact on Utilities, Underground Conduits, Piping, Fire Protection System Tunnels, Tanks Service Water System Ultimate Heat Sink Impact of Construction-Generated Dust and Electrical Auxiliary Building (EAB), Technical Equipment Exhausts Support Center (TSC) and Control Room Emergency HVAC Systems Diesel Generators Impact of Vibratory Ground Motion Offsite Power System Onsite Power Systems Instrumentation and Seismic Monitors Impact of Crane or Crane Boom Failures Safety Related and Important to Safety Structures Impact of Crane Load drops and Foundations Impact of Releases of Flammable, Hazardous or EAB, TSC and Control Room Emergency HVAC Toxic Materials Systems Impact of Wind-Generated, Construction-Related Safety-Related and Important to Safety Structures Debris and Missiles EAB, TSC and Control Room Emergency HVAC Common Air Intake Impact on Electrical Systems and Components Offsite Power System Onsite Power Systems Impact on Cooling Water Systems and Components Service Water System Ultimate Heat Sink Impact on Radioactive Waste Release Points and Gaseous and Liquid Radioactive Waste Parameters Management Systems Impact of Relocation of Structures, Systems or Fire Protection System Components Service Water System Impact of Site Groundwater Depression and Safety-Related and Important to Safety Structures Dewatering SSCs and Foundations Impact of Groundwater and Groundwater Monitoring Facilities Impact of Equipment Delivery and Heavy Safety-Related and Important to Safety Structures Equipment Delivery and Foundations Impact on Drainage Facilities and Structures Safety-Related and Important to Safety SSCs Impact on Site Access and Egress Plant Control Boundaries Plant Structures and Facilities Impact on Onsite Transportation Routes Not Applicable [1] Impact on Slope Stability Not Applicable [1] Impact on Soil Erosion and Local Flooding Safety-Related SSCs and SSCs Important to Safety
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Table 1.10S-2 Hazards During Construction Activies (Continued) Potential Impact Hazard Impacted SSCs Impact on Erosion and Turbidity Control Not Applicable [1] Impact of Encroachment on Plant Control Not Applicable [1] Boundaries Impact of Encroachment on Structures and Safety-Related SSCs and SSCs Important to Safety Facilities Impact on Foundation Integrity Safety-Related Foundations and Foundations Important to Safety Impact on Structural Integrity Safety-Related SSCs and SSCs Important to Safety Impact on Adjacent and Nearby Structures, Safety-Related SSCs and SSCs Important to Safety Systems and Components Impact on Physical Integrity of Structures, Systems Safety-Related SSCs and SSCs Important to Safety and Components Impact of Abandonment of Structures, Systems and Not Applicable [1] Components Impact of Removal of Structures, Systems and Not Applicable [1] Components Impact on Instrumentation and Control Systems Safety-Related SSCs and SSCs Important to Safety and components Impact on Decay Heat Removal Structures, Service Water System Systems and Components Ultimate heat Sink Impact of Vehicle Accidents Safety-Related SSCs and SSCs Important to Safety Impact of Rail Car Derailments Safety-Related SSCs and SSCs Important to Safety Impact of Shared System(s) Tie-ins and Fire Protection System and Components Connections Makeup Water Preparation System [1] Communications [1] Impact on Flooding Design Basis/Flood Protection Not Applicable [1] Measures for STP Units 1 & 2
[1]SSCs with LCOs are not impacted.
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Table 1.10S-3 Managerial and Administrative Construction Controls Construction Hazards to SSCs Managerial Control Impact on Transmission Power Lines and Offsite Safe standoff clearance distances will be Power Lines established for the existing transmission power lines. Construction Engineering to verify standoff distance for all large modules, the reactor vessel and large equipment to be transported beneath energized electric lines to meet minimum standoff clearance requirements.
Administrative procedure controls will be implemented to require compliance.
Physical warning or caution barriers and signage will be erected along transport routes. Impact on Transmission Towers Administrative procedure controls will be implemented to avoid equipment collisions with electric transmission support towers. Physical warning or caution barriers and signage will be erected to protect electric transmission support towers. Engineering analyses will be performed should pre-job review indicate that safe standoff distances may be encroached upon. Impact on Utilities, Underground Conduits, Piping, Administrative procedure controls for grading, Tunnels, Tanks excavation and pile driving will be developed requiring the location and identification of equipment or underground structures that must be relocated, removed, or left in place and protected prior to the work activity. Impact of Construction-Generated Dust and Construction environmental controls will be Equipment Exhausts implemented to control fugitive dust and dust generation. Potentially affected system air intakes and filters will be periodically monitored to ensure limits are not exceeded. Impact of Vibratory Ground Motion Construction administrative procedures, methods, and controls will be implemented to ensure ground Impact on Instrumentation and Control Systems vibration and instrumentation limit settings are not and Components exceeded.
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Table 1.10S-3 Managerial and Administrative Construction Controls (Continued) Construction Hazards to SSCs Managerial Control Impact of Crane or Crane Boom Failures Construction standoff distance controls will be implemented to prevent heavy load impacts upon Impact of Crane Load Drops SSCs from crane boom failures and crane load drops. Drop analyses will be performed should pre- Impact on Instrumentation and Control Systems job review indicate that standoff distances may be and Components encroached upon.
Impact on Foundation Integrity
Impact on Structural Integrity Impact of Shared System Tie-ins and Connections Construction controls for tie-ins and between STP 3 & 4 interconnections into operating Unit 3 systems will be established by engineering and approved by the Impact on Instrumentation and Control Systems STP 3 Operations Department and Components STP 4 construction work packages and instructions Impact on Electrical Systems and Components for tie-ins and interconnections with STP 3 (shared) systems will be prepared, reviewed and approved in Impact on Water Systems accordance with engineering requirements and STP 3 Operations Department requirements and procedures.
A pre-job review will be conducted by engineering prior to performing tie-in or interconnection work.
STP 4 construction work packages for system tie-in and interconnection with STP 3 (shared systems) require authorization to start work from the STP 3 control room shift manager or other designated STP 3 Operations Department official. Impact of Releases of Flammable, Hazardous or Engineering and construction environmental, safety Toxic Materials and Missile Generation and health controls will limit transport, storage, quantities, type and use of flammable, hazardous, toxic materials and compressed gasses to assure that the control room envelope air intake design bases are maintained. Construction safety and storage controls will assure that missile generation events from compressed gasses are within the design basis. Impact of Wind-Generated, Construction-Related Construction procedure controls will address Debris and Missiles equipment, material storage and transport during high winds or high wind warnings. Existing plant procedures will be followed during severe weather conditions which may call for power reduction or shut down.
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Table 1.10S-3 Managerial and Administrative Construction Controls (Continued) Construction Hazards to SSCs Managerial Control Impact on Electrical Systems and Components Engineering analysis will identify any STP 1 & 2 electrical systems and components, and any I&C Impact on Instrumentation and Control (I&C) systems and components within or near the STP Systems and Components 3 & 4 construction area. These items will be isolated and relocated to within the STP 1 & 2 area in accordance with engineering requirements and STP 1 & 2 Operations Department instructions and requirements as applicable.
Construction administrative procedures will provide protective controls established by engineering and approved by the STP 1 & 2 Operations Department as applicable for any STP 1 & 2 electrical or I & C systems and components which cannot be moved.
Engineering analysis will identify any STP 3 electrical systems and components and I&C systems and components within or near the STP 4 construction area. These items will be isolated and relocated to within the STP 3 area in accordance with engineering requirements and STP 3 Operations Department instructions and requirements.
Construction administrative procedures will provide protective controls established by engineering and approved by the STP 3 Operations Department as applicable for any STP 3 electrical systems and components and I&C systems and components which cannot be moved. Impact on Cooling Water Systems and Components Transport of heavy load equipment over buried cooling water piping will be prohibited without an Impact on Decay Heat Removal SSCs engineering evaluation.
Physical warning, standoff distances or caution barriers and signage will be erected. Impact on Cooling Water Systems and Components Transport of heavy load equipment over buried cooling water piping will be prohibited without an Impact on Decay Heat Removal SSCs engineering evaluation.
Physical warning, standoff distances or caution barriers and signage will be erected. Impact on Radioactive Waste Release Points and Engineering evaluation and managerial controls will Parameters be implemented, as necessary, to ensure there is no construction activity which could cause radioactive releases beyond the established limits.
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Table 1.10S-3 Managerial and Administrative Construction Controls (Continued) Construction Hazards to SSCs Managerial Control Impact of Relocation of Structures, Systems or Engineering pre-job review will identify SSCs that Components require relocation and temporary or permanent design changes will be implemented, if required. Impact of Site Groundwater Depression and Engineering controls will be implemented to Dewatering maintain groundwater depression within limits to protect important safety structures and foundations. Impact on Foundation Integrity
Impact on Structural Integrity Impact on Drainage Facilities and Structures Physical warning or caution barriers and signage will be erected to protect drainage facilities and structures. Engineering analyses will be performed should pre-job review indicate that safe standoff distances may be encroached upon. Impact on Soil Erosion and Local Flooding Engineering Controls will be implemented to assure that the site flooding design basis is maintained for the operating units during construction activities that may alter site drainage requirements. Soil erosion control measures will be implemented to assure site drainage requirements are not impacted. Impact of Encroachment on Structures and Pre-job reviews will be performed to identify Facilities construction encroachment impact upon nearby operating unit SSCs and facilities. Engineering Impact on Adjacent or Nearby Structures, Systems controls will be implemented as required to protect and Components the identified SSCs and facilities.
Impact on Physical Integrity of SSCs
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Table 1.10S-3 Managerial and Administrative Construction Controls (Continued) Construction Hazards to SSCs Managerial Control Impact of Equipment Delivery, Heavy Equipment Engineering controls will be implemented to Delivery, and Vehicular Traffic establish rail transport speed limit and maximum rail loading weights onsite. General equipment and Impact on Safety Related Structures and heavy equipment movement controls, limitations, Foundations and vehicular speed limits will be established by Engineering. Impact of Vehicle Accidents
Impact of Rail Car Derailments Impact on Site Access and Egress Plant signage will be erected to identify construction worker access and egress routes and to direct construction deliveries.
Construction equipment orders will include delivery location instructions.
Plant signage will be modified as necessary to direct operating plant worker access and egress routes.
Operating plant equipment orders will include delivery location instructions.
Impacts of Construction 1.10S-11 Rev. 12
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1.10S-12 Impacts of Construction Rev. 12
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1A Response to TMI Related Matters The information in this appendix of the reference ABWR DCD, including all subsections and tables, is incorporated by reference with the following departures and supplements.
STD DEP T1 2.3-1
STD DEP T1 2.4-3
STD DEP T1 2.14-1
1A.2.7 Post-Accident Sampling [II.B.3] STD DEP T1 2.14-1
(2) There shall be onsite capability to perform the following within the 3 hour time period:
(a) Determine the presence and amount of certain radionuclides in the reactor coolant and containment atmosphere that may be indicators of the degree of core damage. Meets the requirements of NUREG-0737. (b) Hydrogen in containment atmosphere. Hydrogen in containment atmosphere is measured by the Containment Atmospheric Monitoring System. Meets the requirements of NUREG-0737 with the exception that the design follows the guidance of RG 1.7 Rev. 3, which permits the hydrogen monitor to be classified as non-safety related nonsafety- related. (c) Dissolved gases, chloride and boron in liquids. Dissolved gases are discussed in item 4 below. Meets the requirements concerning chloride and boron of NUREG-0737. (d) Inline monitoring capability is acceptable. No inline monitors are provided in PASS.
1A.2.13 Containment Design – Dedicated Penetration [II.E.4.1] STD DEP T1 2.14-1
Response A Flammability Control System is provided to control the concentration of oxygen in the primary containment. The FCS utilizes two permanently installed recombiners located in the secondary containment. The FCS is operable in the event of a single active failure. The FCS is described in Subsection 6.2.5.
The Flammability Control System, including the recombiners, has been deleted from the ABWR design as described in Subsection 6.2.5. Accordingly, no penetrations are required for the recombiners.
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1A.2.17 Instruments for Monitoring Accident Conditions [II.F-3] STD DEP T1 2.14-1
Response The ABWR Standard Plant is designed in accordance with Regulatory Guide 1.97, Rev. 3. A detailed assessment of the Regulatory Guide, including the list of instruments, is found in Section 7.5. The hydrogen and oxygen monitors are declassified to nonsafety-related, as permitted by Regulatory Guide 1.7, Rev. 3.
1A.2.23 Modify Break-Detection Logic to Prevent Spurious Isolation of HPCI and RCIC Systems [II.K.3(15)] STD DEP T1 2.4-3
Response The ABWR design utilizes the motor-driven HPCF System rather than the turbine- driven HPCI System for high pressure inventory maintenance. Therefore, this position is only applicable to the turbine-driven RCIC System.
The STP ABWR design for the RCIC System utilizes a flow control system that is an integral part of the pump and turbine. Pump discharge passes through a venturi. The pressure differential between the venturi inlet and throat work together with a balance piston and spring to control the steam flow to the turbine, which in turn adjusts the pump speed and flow.
This is an improvement relative to existing BWR plant designs in which flow control is performed external to the pump and turbine, where flow is measured in a flow element and evaluated in a flow controller to generate an electrical signal to an electro-hydraulic flow control valve to signal a servo to adjust the position of the control valve.
See Subsection 1A.3.8 for COL license information requirements.
1A.2.34 Primary Coolant Sources Outside Containment Structure [III.D.1.1(1)] STD DEP T1 2.14-1
Response Leak reduction measures of the ABWR Standard Plant include a number of barriers to containment leakage in the closed systems outside the containment. These closed systems include:
(1) Residual Heat Removal (8) Post-Accident Sampling (2) High Pressure Core Flooder Monitoring (9) Process Sampling (3) Low Pressure Core Flooder (10) Containment Atmospheric Monitoring (4) Reactor Core Isolation Cooling (11) Fission Product Monitor (Part of LDS) (5) Suppression Pool Cleanup (12) Hydrogen Recombiner
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(6) Reactor Water Cleanup (12) Standby Gas Treatment (7) Fuel Pool Cooling and Cleanup
STD DEP T1 2.3-1
Leakage within and outside the primary containment are continuously monitored by the Leak Detection and Isolation System (LDS) for breach in the integrity of the containment. Upon detection of a leakage parameter, the LDS will automatically initiate the necessary control functions to isolate the source of the break and alerts the operator for corrective action. The MSL tunnel area is monitored for high radiation levels and for high ambient temperatures that are indicative of steam leakage. The Turbine Building is also monitored for high area ambient temperatures for MSL leakage. The resulting action causes isolation of the MSIVs and subsequent shutdown of the reactor.
1A.3 COL License Information 1A.3.1 Emergency Procedures and Emergency Procedures Training Program The information in this subsection of the reference ABWR DCD is replaced in its entirety with the following site-specific supplemental information, which addresses COL License Information Item 1.5.
Emergency procedures based on the emergency procedures guidelines will be developed and implemented prior to fuel loading (Subsection 1A.2.1). The Emergency procedures will be developed consistent with the plant operating procedure development plan in Section 13.5. (COM 1A-1)
Emergency Procedures Training is included in the operations training program discussed in Section 13.2.
1A.3.2 Review and Modify Procedures for Removing Safety-Related Systems from Service The information in this subsection of the reference ABWR DCD is incorporated by reference with the following site-specific supplement, which addresses COL License Information Item 1.6.
Administrative procedures will be developed by the licensee prior to fuel load directing that approval be required for the performance of surveillance tests and maintenance for safety- related systems, including equipment removal from service and return to service to assure the operability status is known. These procedures will be developed consistent with the plant operating procedure development plan in Section 13.5. (COM 1A-2)
1A.3.3 In-Plant Radiation Monitoring The information in this subsection of the reference ABWR DCD is incorporated by reference with the following site-specific supplement, which addresses COL License Information Item 1.7.
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Equipment, training, and procedures necessary to accurately determine the presence of airborne radioiodine in areas within the plant where plant personnel may be present during an accident will be developed prior to fuel loading, consistent with Section 13.5. The equipment will be specified and the training and procedures developed consistent with FSAR Section 12.3, Radiation Protection Design Features. (COM 1A-3)
1A.3.4 Reporting Failures of Reactor System Relief Valves The information in this subsection of the reference ABWR DCD is incorporated by reference with the following site-specific supplement, which addresses COL License Information Item 1.8.
Administrative procedures will be developed by the licensee prior to fuel load directing that failures of reactor system relief valves be reported in the licensee's annual report to the NRC. These procedures will be developed consistent with the plant operating procedure development plan in Section 13.5. (COM 1A-4)
1A.3.5 Report on ECCS Outages The information in this subsection of the reference ABWR DCD is incorporated by reference with the following site-specific supplement, which addresses COL License Information Item 1.9.
Administrative procedures will be developed by the licensee prior to fuel load directing that instances of ECCS unavailability because of component failure, maintenance outage (both forced or planned), or testing, shall be collected and be reported to the NRC annually. Such reports may consist of the performance indicator report for mitigating systems periodically provided to the NRC as part of the Reactor Oversight Process. These procedures will be developed consistent with the plant operating procedure development plan in Section 13.5. (COM 1A-5)
1A.3.6 Procedure for Reactor Venting The information in this subsection of the reference ABWR DCD is incorporated by reference with the following site-specific supplement, which addresses COL License Information Item 1.10.
Emergency Procedure Guidelines (EPGs) have been written for the ABWR which are applicable to STP 3 & 4. The ABWR EPGs are contained in Appendix 18A. These EPGs are developed based upon the U.S. BWR Owner's Group Emergency Procedure Guidelines, Revision 4, which have been approved by the NRC.
The ABWR EPGs contain RPV Control Guidelines, which contain operator guidance for use of the reactor vents that implement the resolution to TMI Action Plan Item II.B.1. The resolution of II.B.1 is located in subsection 1A.2.5. The RPV Control Guidelines contain a description of the system-based entry conditions and operator actions.
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The operator procedures required by COL License Information Item 1.10 will be developed using the ABWR EPGs prior to fuel loading. These procedures will be developed consistent with Section 13.5. (COM 1A-6)
1A.3.7 Testing of SRV and Discharge Piping The information in this subsection of the reference ABWR DCD is incorporated by reference with the following site-specific supplement, which addresses COL License Information Item 1.11.
STP 3 & 4 will utilize SRVs and discharge piping that are similar to those that have been tested and utilized in operating BWRs. Testing of the SRVs and discharge piping is included in the Initial Test Program described in Section 14.2.
1A.3.8 RCIC Bypass Start System Test The information in this subsection of the reference ABWR DCD is replaced in its entirety with the following site-specific supplemental information, which addresses COL License Information Item 1.12.
STD DEP T1 2.4-3
As discussed in Subsection 1A.2.23, the new design RCIC has superior speed regulation than previous designs, so the bypass line and valve are no longer required. As part of the Initial Test Program, an RCIC start test will be performed to confirm system startup characteristics.
The RCIC start test is included in the Initial Test Program described in Section 14.2.
Response to TMI Related Matters 1A-5/6
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1AA Plant Shielding to Provide Access to Vital Areas and Protective Safety Equipment for Post-Accident Operation [II.B.2] The information in this appendix of the reference ABWR DCD, including all subsections and tables, is incorporated by reference with the following departures.
STD DEP 1AA-1
STD DEP T1 2.4-1 (Table 1AA-2)
STD DEP T1 2.14-1 (Table 1AA-3)
STD DEP Admin (Table 1AA-2)
1AA.2 Summary of Shielding Design Review STD DEP 1AA-1
The results of the review are:
(2) Based upon the accident source terms of Regulatory Guides 1.3 and 1.7 and Standard Review Plan 15.6.5 including normal operations, the vital equipment exposures will be enveloped based upon the table below:
Area Gamma (Gy) Beta (Gy) ECCS Rooms 4x105 6x105 8x107 SGTS Area 5x105 3x107 2x10-1 3x102 1AA3.2 Vital Area and Systems STD DEP T1 2.14-1
A vital area is any area which will or may require occupancy to permit an operator to aid in the mitigation of or recovery from an accident. Areas which must be considered as vital after an accident are the control room, technical support center, sampling station, sample analysis area and the HPIN nitrogen supply bottles.
The vital areas also include consideration (in accordance with NUREG- 0737, II.B.2) of the post-LOCA hydrogen control system, containment isolation reset control area, manual ECCS alignment area, motor control center and radwaste control panels. However, the ABWR design does not require a containment isolation reset control area or a manual ECCS alignment area, as these functions are available from the control room. Those vital areas which are normally areas of mild environment, allowing unlimited access, are not reviewed for access.
Essential systems specific to the ABWR to be considered post-accident are those for the ECCS, fission product and combustible gas control and the auxiliary systems necessary for their operation (i.e., instrumentation, control and monitoring, power, cooling water, and air cooling).
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1AA.5.1.2 Emergency Core Cooling Systems and Auxiliaries STD DEP T1 2.4-1
The fuel pool cooling function (Subsection 1.2.2.7.2) is also included on the basis that a recently unloaded fuel batch could require continued cooling during the post-accident period. This function is also supplemented by the RHR Fuel Pool Cooling Mode as described in Section Subsection 9.1.3.2. The RHR equipment is environmentally qualified, so access is not required and redundancy is included in system components.
1AA.5.1.3 Combustible Gas Control Systems and Auxiliaries STD DEP T1 2.14-1
Flammability control in the primary containment is achieved by an inert atmosphere during all plant operating modes except for operator access for during refueling and maintenance. and a recombiner system to control oxygen produced by radiolysis The high pressure nitrogen (HPIN) gas supply is described in Subsection 1.2.2.12.13. The Containment Atmospheric Monitoring System (CAMS) measures and records containment oxygen/hydrogen concentrations under post-accident conditions. It is automatically initiated by detection of a LOCA (Subsection 7.6.1.6). Table 1AA-3 lists the combustible gas control principal components and their locations.
1AA-2Plant Shielding to Provide Access to Vital Areas and Protective Safety Equipment for Post-Accident Operation [II.B.2] Rev. 12 STP 3 & 4 Final Safety Analysis Report
Table 1AA-2 Post-Accident Emergency Core Cooling Systems and Auxiliaries Equipment MPL Location HPCF SP Water Level T31-LT0058A,B,C,D By HPCF Rm. B,C (SC) LPCF FPC Supply Valve E11-F015A,B,C Valve Rm. A,B,C (SC)
Table 1AA-3 Post-Accident Combustible Gas Control Systems and Auxiliaries
Equipment MPL Location FCS Recombiner & Auxiliaries T49 A001A,B (PC) RHR Cooling/Isol. Valve T49 F008,010;A,B (PC)(SC) Flow T49 FT002,004;A.B Inst. Rack Rm. A,B (SC) Pressure T49-PT003A,B Inst. Rack Rm. A,B (SC)
Plant Shielding to Provide Access to Vital Areas and Protective Safety Equipment for Post-Accident Operation [II.B.2] 1AA-3/4
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1B Not Used The information in this appendix of the reference ABWR DCD is incorporated by reference with no departures or supplements.
Not Used 1B-1/2
Rev. 12
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1C ABWR Station Blackout Considerations The information in this appendix of the reference ABWR DCD, including all subsections and tables, is incorporated by reference with the following departures and supplement.
STD DEP 1.8-1 (Table 1C-3)
STD DEP 8.3-1 (Tables 1C-1, 1C-2, 1C-3)
1C.2 Discussion 1C.2.2 Plant SBO Design Basis 1C.2.2.2 Specific SBO Design Basis STD DEP 1.8-1
STD DEP 8.3-1
The CTG will automatically start, accelerate to required speed, reach required voltage and frequency and be ready to accept PIP loads within twoin less than 10 minutes of the receipt of its start signal.
The CTG will be housed in aan International Building Code (IBC)Uniform Building Code structure which is protected from adverse site weather related conditions.
1C.2.3 Plant SBO Safety Analysis 1C.2.3.1 Plant Event Evaluations
1C.2.3.1.1 Plant Normal Operation STD DEP 8.3-1
The normal and alternate preferred AC power sources supply safety-related and non- safety-related loads. Power to these loads are supplied from the unit auxiliary transformers (UATs) units and the reserve auxiliary transformer (RAT)transformers (RATs).
The CTG is designed to supply standby power to the non-Class 1E 6.94.16kV buses which carry the plant investment protection (PIP) loads. The CTG automatically starts on detection of under voltage on the PIP buses. When the CTG is ready to assume load, if the voltage is still deficient, power automatically transfers to the CTG (refer to Figure 8.3-1).
The CTG can also supply standby power to the non-Class 1E 6.913.8kV power generation buses which supply feedwater andcondensate and condensate booster pumps. These buses normally receive power from the unit auxiliary transformers.and supply power to the plant investment protection (PIP) buses through a cross-tie. The cross-tie automatically opens on loss of power but Breakers on the CTG buses and power generation buses may be manually reclosed if it is desired to operate a
ABWR Station Blackout Considerations 1C-1 Rev. 12
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condensate and condensate booster pump from the combustion turbine generator or the reserve auxiliary transformer.which are connectable to the PIP buses This arrangement allows the powering of load groups of non-Class 1E equipment in addition to the Class 1E divisions which may be used to supply water to the reactor vessel (refer to Figure 8.3-1).
1C.2.3.1.3 SBO Events STD DEP 8.3-1
The CTG is the AC power source during an SBO event. The CTG can supply 6.94.16kV Class 1E buses through the realignment of pre-selected breakers during SBO events. The CTG will reach operational speed and voltage in 2 less than 10 minutes and will be available for bus connection within 10 minutes. Upon a LOPP, the CTG is automatically started and configured to non-safety-related PIP loads. Plant operators using appropriate procedures will reconfigure any of the 6.94.16 kV Class 1E buses to accept CTG power. Refer to Tier 2 Subsections 8.3.1.1.7 and 9.5.11.
1C.2.3.2 Alternative AC Power Source Evaluation STD DEP 8.3-1
The alternate AC power source (1) is a combustion turbine generator, (2) is provided with an immediate fuel supply that is separate from the fuel supply for other onsite emergency AC power systems, (3) fuel will be sampled and analyzed consistent with applicable standards, (4) is capable of operating during and after a station blackout without any AC support systems powered from the preferred power supply or the blacked-out units Class 1E power sources (5) is designed to power all of the PIP and/or Class 1E shutdown loads necessary within 10 minutes of the onset of the station blackout, such that the plant is capable of maintaining core cooling and containment integrity (6) will be protected from design basis weather events (except seismic and tornado missiles) to the extent that there will be no common mode failures between offsite preferred sources and the combustion turbine generator power source, (7) will be subject to quality assurance guidelines commensurate with its importance to SBO, (8) will have sufficient capacity and capability to supply one division two divisions of Class 1E loads, (9) will have sufficient capacity and capability to supply the required non-Class 1E loads used for a safe shutdown, (10) will undergo factory testing to demonstrate its ability to reliably start, accelerate to required speed and voltage and supply power within twoin less than 10 minutes, (11) will not normally supply power to nuclear safety-related equipment except under specific conditions, (12) will not be a single point single failure detriment to onsite emergency AC power sources, and (13) will be subject to site acceptance testing; periodic preventative maintenance, inspection, testing; operational reliability assurance program goals.
1C.4 COL License Information 1C.4.1 Station Blackout Procedures The following site-specific supplement addresses COL License Information Item 1.13.
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The station blackout procedure(s) will be developed consistent with the plant operating procedure development plan in Section 13.5. (COM 1C-1)
ABWR Station Blackout Considerations 1C-3 Rev. 12 STP 3 & 4 Final Safety Analysis Report fsite preferred pacity and capabilities and capabilities pacity rnate AC (AAC) power source to ackout events (defined in 50.2). in 50.2). (defined ackout events d will be rated at a minimum of dependent from of en designed to accommodate AC to accommodate en designed Compliance MWe within 1 minute. within MWe n battery and other auxiliary support loads 7.2 G will have sufficient ca MWe and be capable of accepting shutdown loads shutdown of accepting be capable and MWe minimum of 20 minimum to power the necessary reactor core coolant, control and protective and protective control coolant, core reactor the necessary to power systems including statio needed to bring the plant to a safe and orderly shutdown condition condition shutdown orderly and a safe to the plant to bring needed (defined in 50.2). The CTG supplie and onsite Class 1E sources. A ten (10) minute interval is used as interval Class minute onsite 1E sources. and A ten (10) AAC power The event duration. SBO the for basis the ABWR design plant. to the source power a diverse provides source The ABWR utilize design will an alte mitigate and recoverfrom bl station generator turbine a combustion be will source AAC power The in be totally The CTG will (CTG). 9 Additionally, the plant has be the plant Additionally, the The AAC limits up to 8 hours. losses a period source for power to 10 minutes. SBO event within 10 10 minutes. within (3) three include sources power emergency plant onsite current The to designed which are DG divisions redundant and independent 5 approximately supply The ABWR design CT design ABWR The emergency AC power sources Table 1C-1 ABWR Design Compliance with 10CFR50.63 Regulations with 10CFR50.63 Compliance ABWR Design 1C-1 Table Requirements (i) The redundancy of the onsite The redundancy (i) able to withstand for a specified duration and recover from a station a station from recover and duration a specified for to withstand able blackout as defined in § 50.2. The specified station blackout duration shall factors: following the on be based (1) Each light-water-cooled nuclear power plant licensed to operate must be must to operate licensed plant power nuclear light-water-cooled Each (1) 10CFR50-63 Loss of all alternating current power. current alternating all of Loss 10CFR50-63 power. current alternating of all Loss 50.63 (a) Requirements
1C-4 ABWR Station Blackout Considerations Rev. 12 STP 3 & 4 Final Safety Analysis Report less than less than in considerations are consistent are considerations ) above, the following is noted. is noted. following the ) above, Uponloss of offsite power one of the three safety-related safety-related of three one the rcuit breakers.The alternativeAC pick up the Class 1E buses will reactor will have automatically ically start, and within 2 ically start, Compliance minutes be up to required speed and voltage. It will then It will voltage. and speed to required be up minutes In addition to the discussion under (a to the discussion under In addition SBO time ABWR design duration The and NUMARC-87-00. RG1.155 with ci two by closing buses 1E) (Class (LOPP) and upon the subsequent loss of all on site AC emergency emergency AC site on all loss of subsequent the upon and (LOPP) the CTG DGs), redundant and independent (three sources power to any connected manually can be (AC)automat power source will 10 10 automatically connect to selected PIP buses (non-Class 1E) 1E) loads. PIP (non-Class to selected buses connect automatically During the first 10 minutes, the tripped, the main steam isolation valves (MSIVs) closed, and the RCIC actuated. The RCIC system will automatically control reactor coolant level. Any necessary will also be automatic. relief valve operation Within SBO interval,the 10 minute none of the above actions will actions. operator or manual AC power require The reconfiguration of the CTG to room. control the from breakers two circuit of closure manual require safe to the safety the remaining power of bus(es), restoration Upon loads will be energized. shutdown section, including a justification Requirements Table 1C-1 ABWR Design Compliance with 10CFR50.63 Regulations (Continued) Regulations with 10CFR50.63 Compliance ABWR Design 1C-1 Table compliance with paragraph (a) of this of this (a) with paragraph compliance for the selection basedthe on fourfactors identifiedin paragraph (a)of section this licensed to operate after the effective date of this amendment, the the this amendment, of date effective the after to operate licensed by below to the Director 270 defined the information submit shall licensee issuance: of license the date after days (i) A proposed station blackout duration to be used in determining (1) Information Submittal. For each light-water-cooled nuclear power plant plant power nuclear light-water-cooled each For Submittal. Information (1) (b) Limitation of scope Limitation (b) Implementation (c)
ABWR Station Blackout Considerations 1C-5 Rev. 12 STP 3 & 4 Final Safety Analysis Report trated 1) by the manufacturer’s part of his operational reliability of part lly initiated upon the loss of G will achieve required speed and herefore, no coping analysis is analysis no coping herefore, minutes. The CTG will be manually Compliance emergency diesel generator systems will in less than 10 in less power to the PIP buses. The CT The ABWR CTG will be automatica within 2 voltage On site emergency AC sources are not shared between units. between not shared are AC sources On site emergency 10 within loads shutdown power to is available source CTG AAC The T above. described as minutes required. In addition, the to battery the ABWR with an is designed 8-hour In addition, required. Also, AC power. for need the without blackout station accommodate the three independent with the one DG failure, out a single plus service, of accommodate plant to the safe shutdown. of bringing DG remaining capable connected to safe shutdown buses within 10 minutes. These These 10 minutes. within buses to safe shutdown connected be demons will equipment capabilities 3) and tests 2) by the CTG initial startup tests, component as the COL applicant periodically by assurance program. design. unit plant arrangement is a single ABWR design The ensure that all units can units ensure that all at the plant has this capability at the plant has this capability thstand station blackout provided an station thstand the units. At sites where onsite onsite where sites At units. the m, the capacity and capability for and capability m, the capacity to power the shutdown buses within 10 buses shutdown the to power until the alternate AC source(s) and and AC source(s) alternate the until Requirements d capability as required to d capability Table 1C-1 ABWR Design Compliance with 10CFR50.63 Regulations (Continued) Regulations with 10CFR50.63 Compliance ABWR Design 1C-1 Table from onset of the station blackout blackout station of the onset from time The operate. to up and lined started are equipment shutdown required and source(s) AC power the alternate of alignment and for startup required this equipment shall be demonstrated bytest. Alternate AC source(s) serving shared not are AC source emergency onsite unit site where a multiple a minimu must have, as between units of blackout in any with a station coping AC source(s) alternate the units, between shared are AC sources emergency an the capacity must have analysis is performed whic h demonstrates th analysis is § in defined as (non-DBA) shutdown safe in maintained and to brought be be can and requirements above the meets AC source(s) alternate the If 50.2. test by available to be demonstrated is analysis required. coping then no blackout, of onset of station minutes the will constitute acceptable capability to wi capability will constitute acceptable (2) Alternate AC source: The alternate AC power source(s), as defined in § 50.2, in § 50.2, as defined source(s), AC power AC The alternate source: Alternate (2)
1C-6 ABWR Station Blackout Considerations Rev. 12 STP 3 & 4 Final Safety Analysis Report non- At least others MWe, which is MWe, 20 9
at ed by test to show that it to show that by test ed MWe. at least will be automatically started started be automatically will 7.2 the CTG from the PIP buses. minutes, and safety-related loads within within loads safety-related and minutes, Compliance non-Class 1E circuit breaker breaker 1E circuit non-Class in less than 10 breakers separate breakers At least two open circuit breakers—one Class 1E and the other the and 1E Class breakers—one circuit open The ABWR AAC power source is not normally connected to the the to connected normally not is source power ABWR AAC The system. Two or AC power emergency the onsite preferred Class 1E— separate the CTG from the safety-related emergency emergency safety-related the CTG from the 1E— separate Class buses. of to any the connected is also not normally source The AAC power associated non-safety-related or their sources AC power preferred A buses. two separates more than sufficient capacity to operate safe necessary the to operate capacity sufficient than more shutdownloads which are lessthan 5 and reach rated speed and voltage and be available to supply PIP to supply available be and and voltage speed rated reach and 2 loads within The ABWR AAC design power source 10 minutes for any loss of preferred offsite power sources (LOPP). The designprovisions has to assurethetimely manual the of more or one any the AAC (CTG) and between interconnection buses. shutdown safety-related The ABWR AAC design will be demonstrat 10 minutes. within buses to safety-related be connected can Therefore,no coping analysisrequired. is The ABWR AAC power source is rated isions to be manually connected to to connected to be isions manually Table 1C-2 ABWR Design Compliance with RG 1.155 Compliance Design 1C-2 ABWR Table Requirements preferred or the blacked-out unit’s onsite emergency system. AC power emergency onsite blacked-out unit’s the or preferred onset of station blackout and have prov and blackout onset station of for required time The safety as all of buses redundant required. or the one as 1 hour than not be more should available this making equipment demonstrated by test. If the AAC power source can be demonstrated by of the minutes within 10 buses s hutdown the to power test available to be is analysis blackout, coping no required. onset of station systems necessary for coping with a blackoutstation for the time required shutdown. plant in safe the maintain and to bring 1. The AAC power source should not normally be directly connected to the the to connected directly be not normally should source AAC power The 1. 3.The AAC power source should be available in a timely manner after the the after in a timely manner be available should source AAC power 3.The 4. The AAC power source should have sufficient capacity to operate the the to operate capacity have sufficient should source AAC power The 4. Regulatory Guide 1.155—Station Blackout Guide 1.155—Station Regulatory Regulatory Position 3.3.5AAC If anpower sourceis selected specifically for satisfyingthe criteria: the meet following should the design blackout, station for requirements
ABWR Station Blackout Considerations 1C-7 Rev. 12 STP 3 & 4 Final Safety Analysis Report Compliance breakers separate the onsite emergency power power emergency onsite the separate breakers At least two SBO Recovery with AAC Power Source AAC Power with SBO Recovery buses from the CTG. One breaker is Class 1E and the breakerbuses from the CTG. closest 8.3-1). to the CTG 1E Figure is non-Class (see Two ABWR AAC Power Source Table 1C-2 ABWR Design Compliance with RG 1.155 (Continued) with RG 1.155 Compliance ABWR Design 1C-2 Table Requirements Tank or Alternate) or Tank Air System) Air (Compressed Instrument Water Source (Existing Condensate Storage Storage Condensate (Existing Source Water Alternate AC Sources Requiredif connected to Class 1E buses. toSeparationprovided be by 2 circuit breakers 1 and Class 1E at the bus (1 in series 1E). non-Class Appendix B - Guidance Regarding Systems/Components B Regarding Appendix - Guidance Independence from Existing Safety-Related Systems
1C-8 ABWR Station Blackout Considerations Rev. 12 STP 3 & 4 Final Safety Analysis Report
the AAC Non-Class At least two breakers separate breakers minutes, and is capable of is and capable minutes, available in a timely manner (but not normally connected to) to) the connected normally (but not minutes. The AAC power supply is supply AAC power The minutes. Compliance less than 10 less than in less than ten (10) in less normally open breakers separate the AAC CTG from the the AAC CTG from the separate breakers open normally normally open breaker separates breaker open normally
failure between preferred poweronsite or power AC sources. The ABWR AAC power source is a diverse power supply to the is totally supply AAC power DGs. The emergency onsite normal sources. The power onsite and the preferred of independent for is and available starts automatically source AAC power in two loading connectable to a Class 1E bus through the actuation of two (2) is source AAC power The circuit breakers. operated manual and mechanically, physically, normally electrically, environmentally isolated from the preferred and onsite power LOPP during used normally is source AAC power The sources. a number for be used CTG can the However, SBO events. and etc.). backup, (e.g . maintenance services operational of after onset of a SBO AAC the The event. power source after voltage and speed required attains LOPP, on starts automatically (2) two within being connected to shutdown loads within ten (10) minutes. ten (10) within loads to shutdown connected being preferred or onsite emergency AC power sources. safety-related onsite emergency power A buses. power onsite emergency single safety-related 1E CTG from the non-safety-related PIP buses (preferred power) power) PIP (preferred buses CTG the non-safety-related from 8.3-1). Figure (see Two (i) The design is connectable to is connectable design The (i) (ii) The ABWR design has a minimal potential for common for cause common potential has a minimal ABWR design The (ii) (iii) The ABWR AAC power source is n of all systemsnecessaryall n of to demonstrate operability rnating current (AC) power source source (AC) power current rnating use failure with offsite power or the connected to the preferred or onsite or onsite preferred to the connected nearby a nuclear power plant and meets the the meets and plant power a nuclear nearby r after the onset of station blackout the onset of station r after Table 1C-3 ABWR Design Compliance with NUMARC 87-00 Guidelines with NUMARC 87-00 1C-3 ABWR Design Compliance Table Requirements and reliability for operatio Appendix A — Definitions Appendix ed, and tested periodically irements: and reliability as set forth in Appendix B for coping with a station blackout and for the time required to bring and to bring for the time required and blackout a station with coping for as Hot or Standby, Shutdown (Hot in safe shutdown the plant maintain appropriate) onsite AC power sources onsite emergency AC power systems AC power emergency (v) Is inspected, maintain (v) Is inspected, (iii) Is available in a timely manne (iv) Has sufficient capacity (ii) Has minimal potential for common ca ALTERNATE AC POWERSOURCE. An alte ALTERNATE or at located and to that is available following requ (i) Is connectable to but not normally normally not but to connectable Is (i)
ABWR Station Blackout Considerations 1C-9 Rev. 12 STP 3 & 4 Final Safety Analysis Report
MWe. MWe. 20 Building). The International Building one non-Class 1E non-Class one t forth in Appendix B. MWe. The CTG reliability The CTG MWe. 7.2 breakers will be from at least oad. A seven-day fuel supply fuel supply is A seven-day oad. will be capable of being will be capable Building (Turbine Building (e.g., wind, temperature, etc.). temperature, wind, (e.g., two (2) circuit breakers in series (one Compliance ability to guidelinesability se at least CTG bus). Power to the Power to CTG bus). Uniform Building Code The shutdown loads are less than 5 less than are loads shutdown The is 0.95. The ABWR is expected to be in hot shutdown condition condition shutdown in hot to be ABWR is expected The is 0.95. in condition shutdown cold and in hours, (24) four in twenty ninety-six (96) hours. The CTG is designed to run indefinitely l at SBO conditions rated under available on the site for the CTG. its to demonstrate tested periodically and maintained inspected, operability and reli The ABWR AAC power source is housed in an an in is housed source ABWR The AAC power breaker at the breaker at appropriatesources. DC Code (IBC) AAC power source is physically, mechanically, electrically and electrically and mechanically, is physically, source AAC power onsite power and preferred the from separated environmentally and plant from normal is protected The source AAC sources. power perturbations site environmental (v) The ABWR AAC power source (iv) The ABWR AAC power source is rated a minimum 9 of a minimum is rated ABWR source The AAC power (iv) Class 1E at 1E buses and the Class The ABWR AAC power source is electrically isolated from the Class the from isolated is electrically source power AAC ABWR The by 1E power sources (v) flooding from a pipe break, and (vii) missiles resulting and (vii) missiles break, , elevated temperature or humidity or humidity temperature , elevated connected to Class 1E buses, isolation isolation buses, 1E Class to connected Requirements ement, (iv) water spray, ement, (iv) water spray, ed in this criteria, the AAC system need not be Table 1C-3 ABWR Design Compliance with NUMARC 87-00 Guidelines (Continued) Guidelines NUMARC 87-00 with 1C-3 ABWR Design Compliance Table Appendix B—Alternate AC Power Criteria break, (vi) radiation, pressurization (vi) radiation, break, pipe energy medium or by high caused systems energy or high equipment of rotating the failure from pipe whip, (iii) jet imping protected against the effects of: effects the against protected (a) Failure or misoperation of mechanical equipment, including (i) fire, (ii) shall be provided by two circuit breakers in series (one Class 1E breaker at Class 1E breaker (one in series breakers circuit two by shall be provided the source). protect to 1E breaker non-Class one Class 1E bus and the isolation device. If the is device. If the AAC source isolation AAC Power Source Criteria AAC B.2 Unless otherwise provid Connectability AC Power Systems to Connectability an appropriate through provided shall be AAC power of isolation B.6 Electrical
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1D Negation Action Plan1 1D.1 Introduction (a) The following Negation Action Plan (the Plan) provides requirements and guidance to ensure negation of potential foreign ownership, control or domination (FOCD) over the South Texas Project, Units 3&4 (STP 3&4) licenses held by Nuclear Innovation North America, LLC (NINA), STP Nuclear Operating Company (STPNOC), NINA Texas 3 LLC (NINA 3), NINA Texas 4 LLC (NINA 4), and the City of San Antonio, Texas, acting by and through the City Public Service Board (CPS Energy). This Plan implements measures to fully negate FOCD with respect to matters involving the nuclear safety, security, and reliability of STP 3&4 throughout the design, construction and operation of STP 3&4. The same measures negate potential foreign influence.
(b) The Plan describes the controls implemented to assure that the governance of NINA and licensed activities undertaken by NINA, NINA 3, NINA 4, and STPNOC are not subject to FOCD within the meaning of 10 CFR 50.38 and Section 103.d of the Atomic Energy Act of 1954, as amended (Section 103.d of the Act).
(c) STPNOC is responsible for the operation of STP 3&4. STPNOC is a not for profit Texas corporation that is controlled by a board of four directors, three members of which are appointed by the City of Austin (Austin), CPS Energy, and NRG South Texas LP, an indirect wholly owned subsidiary of NRG Energy, Inc. (NRG Energy). These three directors choose the fourth director, who then also serves as the Chief Executive Officer (CEO) of STPNOC. Austin and CPS Energy are governmental organizations in the State of Texas that are controlled by city councils elected by the citizens of these U.S. cities. NRG Energy is a publicly traded, widely held U.S. corporation, and it is not under FOCD. STPNOC is subject to U.S. control, and it will exercise authority over nuclear safety, security and reliability matters free from any potential for foreign domination or control over its decision making in any area of concern to the NRC under 10 CFR 50.38 and Section 103.d of the Act.
(d) NINA owns and controls both NINA 3 and NINA 4; it also will exercise control over its other subsidiaries involved in the development of STP 3&4. NINA 3, NINA 4 and CPS Energy own STP 3&4, and these owners are responsible for providing the funding for construction, operation and decommissioning of STP 3&4. Pursuant to arrangements among the owners, the owners have allocated primary
1 This Negation Action Plan describes the measures to be implemented based upon the planned execution of the Fourth Amended and Restated Operating Agreement of Nuclear Innovation North America, LLC, and the measures described are fully effective only upon such execution.
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responsibility for funding construction activities to NINA 3 and NINA 4. NINA is the lead applicant and lead licensee responsible for design and construction of each unit until the date on which the Commission makes a finding that acceptance criteria are met under 10 CFR 52.103(g) or allowing operation during an interim period under the combined license under 10 CFR 52.103(c), at which point STPNOC will be the lead licensee responsible for operations.
(e) This Plan has been developed using the guidance provided by the NRC's "Final Standard Review Plan on Foreign Ownership, Control, or Domination," 64 FR 52355 (September 28, 1999) (FOCD SRP). Defense in depth is provided through a number of measures in order to ensure that there is U.S. control over matters relating to nuclear safety, security and reliability, including most significantly the NINA security programs and NINA safety programs, including Quality Assurance. These measures effectively negate the risk that NINA's foreign owned parent company or companies or foreign lenders might exercise control, domination, or influence over matters that are required to be under U.S. control pursuant to the terms of 10 CFR 50.38 and Section 103.d of the Act.
(f) The negation measures are implemented primarily through the terms of the Fourth Amended and Restated Operating Agreement of Nuclear Innovation North America, LLC (the NINA LLC Agreement). Additional requirements and further details regarding implementation of the negation measures are included in this Plan.
(g) The terms of the NINA LLC Agreement provide that a Security Committee of the NINA Board will be established not later than the first pouring of any safety related concrete for STP 3&4. The Security Committee has the exclusive right to exercise the Board's authority over the matters that are required to be under U.S. control. The Security Committee is made up of U.S. citizens, the majority of whom must be independent directors, who are not employed by NINA, its subsidiaries, its owners, or any of their affiliates. Until the Security Committee is established, the Chief Executive Officer (CEO) of NINA will perform the functions of the Security Committee, except the right to approve a new CEO. Because the Member Director appointed by NRG Energy controls 90% of the votes on the Board of Directors under the current ownership structure of NINA, the NRG Member Director controls the selection of the independent directors.
(h) The governance measures implemented for NINA flow through to the actions of NINA 3 and NINA 4, pursuant to requirements imposed through the governance arrangements for these entities and their parent companies. These entities have adopted provisions to assure
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that the NINA Security Committee exercises ultimate control and direction over matters required to be under U.S. control.
(i) In addition, NINA will also establish a Nuclear Advisory Committee (NAC), prior to pouring any safety related concrete for STP 3&4. The NAC is made up of a group of independent U.S. citizens who are experienced in national security and nuclear safety matters. It provides an oversight function to advise NINA regarding its ongoing compliance with the FOCD restrictions imposed by U.S. law and NRC regulation. If necessary, the NAC can alert the U.S. Government regarding issues involving potential non-compliance with the applicable requirements.
(j) NINA's security programs, including its Safeguards Information Program, assure that only authorized persons are provided access to security related information in accordance with applicable program requirements, and this Plan provides measures to assure that interpretation and implementation of those program requirements are administered under U.S. control. NINA does not possess or control access to restricted data or classified national security information. NINA is not aware of any personnel assigned to NINA (contract personnel, including employees loaned from STPNOC) that are currently maintaining security clearances that would authorize access to restricted data or classified national security information. To the extent that any NINA contract personnel may obtain security clearances in the future or that NINA may hire contract employees that maintain security clearances, such personnel would do so subject to the requirements of security programs controlled by their employer companies and not controlled by NINA. NINA will not interfere with the administration of such programs by other companies, and NINA will require that its personnel comply with all applicable requirements relating to such information.
(k) Upon acceptance of this Plan, changes to this Plan may only be made upon the recommendation of NINA's CEO or upon the recommendation of STPNOC's CEO, and approval of the NINA Security Committee. However, any proposed change that would result in a decrease in the effectiveness of this Plan will not be implemented without the prior approval of the NRC. This Plan also will be subject to the reporting requirements applicable to the FSAR.
(l) Certain FOCD negation measures described in this Plan have been implemented in the NINA LLC Agreement, because it provides for the governance of NINA. NINA will provide NRC with 30 days prior written notice before implementing any material changes to the FOCD negation measures in the NINA LLC Agreement.
(m) NINA’s CEO and Chief Nuclear Officer (CNO) have a special role in assuring that the requirements of this Plan are met, because they
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interact with the NINA Board and its owners, and they oversee the entire STP 3&4 organization. As such, the CEO and CNO have the ability to identify potential FOCD issues involving both direct foreign owner contact at the Board level and indirect contacts that might be made throughout the organization. The CNO is responsible for the NINA Quality Assurance Program (QA Program) and Safeguards Information Program (SGI program), and as such, the CNO assures U.S. control of these programs. The NINA CEO is responsible for this Plan and may delegate roles and responsibilities to the CNO or other executive management personnel. During STP 3&4 operations, roles and responsibilities for assuring the effective implementation of this Plan may be delegated to the STPNOC CEO and STPNOC executive management team.
1D.2 Governance of Nuclear Innovation North America, LLC (a) NINA is a Delaware limited liability company. NINA is owned approximately 90% by the NRG Energy Member (NRG Member) of NINA, Texas Genco Holdings, Inc. (Texas Genco), a Texas corporation, and less than 10% by the Toshiba Member of NINA, Toshiba America Nuclear Energy Corporation (Toshiba America Nuclear), a Delaware corporation. NRG Energy, A Delaware corporation, owns 100% of the voting stock of Texas Genco. Toshiba America Nuclear is a wholly owned subsidiary of Toshiba America, Inc., a Delaware corporation, which is a wholly owned subsidiary of Toshiba Corporation, a Japanese corporation (together, with its U.S. subsidiaries, referred to as the Toshiba Companies). The Shaw Group Inc., a Louisiana corporation, has the right to acquire an ownership interest in NINA from NRG Energy, which would reduce NRG Energy's interest in NINA. The Shaw Group Inc. is publicly traded on the New York Stock Exchange. The exact percentage of potential ownership by The Shaw Group is variable, but as of January 1, 2012 it is estimated it would be less than 5%.
(b) The Board of Directors of NINA is fully vested with and delegated with authority by the owners (“Members”) to conduct the management of the NINA. The Board of Directors operates generally by majority or supermajority vote of the Member Directors, each of whom votes based upon the Member’s ownership interests. As such, the NRG Energy Member Director with approximately 90% of the votes holds a majority and supermajority vote to decide most Board matters, including the selection of the CEO and the CNO of NINA, the members of the Security Committee, and the members of the Nuclear Advisory Committee.
(c) Prior to the execution of the documents necessary to implement any proposed change of ownership of NINA that either individually, or when combined with prior changes, would result in a change in ownership
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greater than 5% of NINA, NINA shall provide complete information to the NRC regarding the proposed transaction and seek either an NRC threshold determination that no license transfer approval is required or NRC’s prior written consent to a license transfer pursuant to 10 CFR 50.80.
(d) NINA will assure that at least 50% of the funding for any licensed construction activity is funded from U.S. sources whether through loans or through equity.
1D.2.1 NINA Board of Directors (a) The business and affairs of NINA are and will be managed under the direction of a Board of Directors (Board), consisting of member appointed directors (Member Directors) including a director to act as Chairman, and two independent directors, who are selected and appointed by the Member Directors. The Chairman is selected by the Member Directors from among their number. The Chairman presides over the meetings of the Board, and otherwise fulfills the functions of the Chairman. The Chairman, and anyone acting for the Chairman, must be a U.S. citizen.
(b) The NINA LLC Agreement provides that two independent directors, who must be U.S. citizens, are selected and appointed by the Member Directors. The independent directors are appointed for a one year term, ending January 31 of each calendar year. However, independent directors may be reappointed year after year. These directors are independent because they may not be officers or employees of NINA, any of its subsidiaries, any of its owners, or any of their affiliated companies. The independent directors and their immediate family members may not have a material relationship with NINA, its subsidiaries, or its parent companies, or their affiliates, such as by being an executive officer or employee, by receiving pension benefits or other compensation for prior service, or by being an executive officer of another company that receives significant revenue from NINA or its affiliates. In accordance with generally accepted practices, the independent directors may receive compensation from NINA for their services as directors.
(c) If any independent director acquires any material ownership or other economic interest in NINA, its subsidiaries, its owners, or any of their affiliated companies, this will be reported to NINA and to the NRC. It is possible that the independent directors may have investment holdings such as in mutual funds or other similar types of pooled investments that themselves may make a wide range of investments that could include investments in issuances of NINA, its subsidiaries, its owners, or their affiliated companies. Given the impracticality of monitoring and/or limiting such investments, it is NINA's intention that such investments would not be considered "material." Direct holdings in
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securities, bonds or other issuances of NINA, its subsidiaries, its owners, or their affiliated companies would be considered material and reportable.
(d) Significantly, the Chairman and the two independent U.S. citizen directors serve on a Security Committee, which has been assigned "exclusive authority" to vote upon and decide for the Board all matters coming before the Board that relate to nuclear safety, security or reliability. In addition, any matter that must be decided under U.S. control can be elevated to the Security Committee, and mechanisms have been established to provide for such matters to be elevated to the Security Committee when necessary. The details of this authority are described further below in Section 2.2 of this Plan.
(e) The Board as a whole has been delegated authority to decide various matters, notwithstanding any delegations of authority to the CEO and other officers. Ordinarily, the Board as a whole would decide these matters which are listed in Section 5.1(a) of the NINA LLC Agreement. However, this reserved authority is itself subject and subordinate to the exclusive authority of the Security Committee. Thus, if U.S. control must be exercised over a Section 5.1(a) matter, such matter would be decided by the Security Committee. Pursuant to Section 5.1(c) of the NINA LLC Agreement, the Member Directors of NINA vote based upon their Member’s ownership percentage of NINA. As such the NRG Energy Member Director casts approximately 90% of the votes and the Toshiba Member Director casts approximately 10% of the votes. Decisions are to be made by majority vote, except:
(i) the decisions listed in Section 5.1(d)(i), which require a 66 2/3% vote;
(ii) the decisions listed in Section 5.1(d)(ii), which require a 100% vote; and
(iii) the limited decisions listed in Section 5.1(d)(iii), which require an affirmative vote by the Toshiba Member Director (such as carrying on business other than that specified in the NINA LLC Operating Agreement or liquidating or dissolving the company).
Provided, however, that all decision-making by the NINA Board of Directors is subject to the delegated authority to the Security Committee.
(f) The Board may delegate authority to the CEO and other executive personnel of the company. It also benefits from the advice and oversight of the members of the Nuclear Advisory Committee, who have substantial expertise in national security and nuclear safety matters, the details of which are described further below in Section 2.4 of this Plan.
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1D.2.2 Security Committee (a) The NINA LLC Agreement provides for a broad delegation of exclusive authority to the Security Committee, in order to assure that the U.S. citizen directors, including the Security Committee's majority of independent directors, have the ultimate authority to make the corporate decisions for NINA regarding: (1) any matter that is to be brought before the Board, where U.S. legal and regulatory requirements direct that the matter must be decided under U.S. control; or (2) any matter that ordinarily might be decided by corporate officers, but where there is a concern that decision making regarding the matter may be subject to foreign control or influence, and U.S. legal and regulatory requirements direct that the matter must be decided under U.S. control. In other words, the Security Committee itself has the authority to decide that a matter must be decided by the Security Committee. The Board and Security Committee delegate authority over the day to day management of the affairs of NINA to its executive personnel. However, as discussed further below, the NINA governance is structured to ensure that the required U.S. control over matters of safety, security and reliability is not circumvented by having suchissues decided without consultation with and oversight by the Security Committee, whenever necessary.
(b) Section 5.1(e) of the NINA LLC Agreement provides that the Security Committee has and shall exercise the exclusive authority of the Board to vote and decide the following matters:
(A) Any matter that, in view of U.S. laws or regulations, requires or makes it reasonably necessary to assure U.S. control;
(B) Any matter relating to nuclear safety, security or reliability, including, but not limited to, the following matters:
(1) Implementation or compliance with any NRC generic letter, bulletin, order, confirmatory order or similar requirement issued by the NRC;
(2) Prevention or mitigation of a nuclear event or incident or the unauthorized release of radioactive material;
(3) Placement or restoration of the plant in a safe condition following any nuclear event or incident;
(4) Compliance with the Atomic Energy Act of 1954 (as in effect from time to time), the Energy Reorganization Act of 1974 (as in effect from time to time), or any NRC rule;
(5) The obtaining of, or compliance with, a specific license issued by the NRC and its technical specifications;
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(6) Conformance with a specific Final Safety Analysis Report, or other licensing basis document; and
(7) Implementation of security plans and procedures, control of security information, control of special nuclear material, administration of access to controlled security information, and compliance with government clearance requirements regarding access to restricted data;
(C) Any other issue reasonably determined by a majority of the members of the Security Committee in office, in their prudent exercise of discretion, to be an exigent nuclear safety, security or reliability issue; and
(D) Appointment of any successor CEO of the Company and Chief Nuclear Officer of the Company, in each case as nominated by the Board.
(c) The provisions of Section 5.1(e)(ii)(C) make clear that this broad authority includes the authority for the Security Committee to decide that a matter involves an issue that must be decided under U.S. control and therefore must be brought before and decided by the Security Committee.
(d) In order to assure that control would be exercised by U.S. citizens who are independent from any foreign entities, Section 5.1(e)(iii) of the NINA LLC Agreement provides that the attendance and participation of the two independent U.S. citizen directors is required to constitute the required quorum for the Security Committee to conduct business.
(e) The ordinary affairs of NINA are managed day to day by the company's executive personnel and managers and supervisors. The Board and the Security Committee have delegated authority to the company's executive personnel, but such delegation is subject to limitations including the ultimate authority of the Board and the Security Committee to make decisions for NINA when necessary. In order to assure that such day to day issues do not fall subject to FOCD in a way that would circumvent the intended U.S. control and authority of the Security Committee, the NINA LLC Agreement provides for a variety of mechanisms by which such issues could be raised and put before the Security Committee, if necessary. Section 5.1.(e)(iv) of the NINA LLC Agreement provides that a Special Meeting of the Security Committee shall be conducted where a request is made that a matter be considered by the Security Committee. Such a request (requiring a Special Meeting for consideration of the matter) may be made by: (A) the CEO; (B) any member of the Security Committee; (C) the NAC; or
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(D) the Board. The Security Committee is required to promptly resolve any issues referred in this manner.
(f) Thus, if a circumstance were to arise where an officer or manager had questions about potential foreign control, domination or influence over a matter, the issue could simply be raised within the NINA organization for further review and consideration. Ultimately, the CEO would be in a position to assess whether the matter was being properly decided free from any inappropriate foreign control, domination or influence, or if the concern should be referred so that the matter would be brought before the Security Committee. The CEO's role in this regard is described further below in Section 2.3. In any event, any person involved in the licensing, design, construction or operation of STP 3&4 (or STP 1&2) may raise a concern regarding any potential FOCD issue. Such a concern may be raised in any manner in which a safety concern may be raised (e.g., supervisor, manager, Corrective Action Program, Employee Concerns Program, or NRC). If any person is not satisfied with the resolution of an FOCD concern that is not referred to the Security Committee, that person may raise the issue directly to one or more members of the Security Committee. If any member of the Security Committee agrees that the issue should be brought before the Security Committee, a Special Meeting is required.
(g) In order to underscore the special role undertaken by the Security Committee, the NINA LLC Agreement provides that each member execute a certificate acknowledging the protective measures undertaken by NINA, as reflected in this Plan. The certificate provides as follows:
By execution of this Certificate, I acknowledge the protective measures that have been taken by Nuclear Innovation North America LLC ("NINA") through adoption and implementation of the provisions of Section 5.1(e) of its Fourth Amended and Restated Limited Liability Company Agreement ("Agreement"), in order to protect against and negate the potential of any foreign ownership, control or domination of NINA within the meaning of 10 CFR 50.38 and Section 103.d of the Atomic Energy Act of 1954, as amended.
I further acknowledge that the United States Government has placed its reliance on me as a United States citizen to exercise all of the responsibilities provided for in Section 5.1(e) of the Agreement; to assure that members of the NINA Board of Directors, the officers of NINA, and the employees of NINA comply with the provisions of Section 5.1(e) of the Agreement; and to assure that the Nuclear Regulatory Commission is advised of any violation of, attempt to violate, or attempt to
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circumvent any of the provisions of Section 5.1(e) of the Agreement, of which I am aware.
As noted in Section 1.D.2.2(a) of this Plan above, Section 5.1(e) of the NINA LLC Agreement provides for U.S. control over the nuclear safety, security, and reliability issues that are required to be under U.S. control. Thus, this Certificate assures the U.S. Government that each individual has responsibility for compliance with these requirements.
(h) In order to underscore the special role of the CEO and CNO in assisting the Security Committee, the NINA LLC Agreement provides that the CEO execute a certificate acknowledging the protective measures undertaken by NINA, as reflected in this Plan. The certificate provides as follows:
By execution of this Certificate, I acknowledge the protective measures that have been taken by Nuclear Innovation North America LLCC (NINA) through adoption and implementation of the provisions of Section 5.1(e) of its Fourth Amended and Restated Limited Liability Company Agreement ("Agreement"), in order to protect against and negate the potential of any foreign ownership, control or domination of NINA within the meaning of Section 103 of the Atomic Energy Act of 1954, as amended.
I further acknowledge that I have a special role to assist in assuring that the Security Committee is able to fulfill its responsibilities in accordance with Section 5.1(e) of the Agreement, and acknowledge that the United States Government has placed its reliance on me as a United States citizen to exercise my best efforts to refer matters for consideration by the Security Committee, as necessary and appropriate, so that the Security Committee can exercise all of the responsibilities provided for in Section 5.1(e) of the Agreement; to assure that members of the NINA Board of Directors, the officers of NINA, and the employees of NINA comply with the provisions of the Section 5.1(e) of the Agreement; and to assure that the Nuclear Regulatory Commission is advised of any violation of, attempt to violate, or attempt to circumvent any of the provisions of Section 5.1(e) of the Agreement, of which I am aware.
(i) Until the Security Committee is established, the CEO will perform the functions of the Security Committee, except the authority to approve a new CEO. In order to underscore the interim role of the CEO in performing the functions of the Security Committee, the NINA LLC Agreement provides that the CEO execute a certificate acknowledging
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the protective measures undertaken by NINA, as reflected in this Plan. The certificate provides as follows:
By execution of this Certificate, I acknowledge the protective measures that have been taken by Nuclear Innovation North America LLCC (NINA) through adoption and implementation of the provisions of Section 5.1(e) of its Fourth Amended and Restated Limited Liability Company Agreement ("Agreement"), in order to protect against and negate the potential of any foreign ownership, control or domination of NINA within the meaning of Section 103 of the Atomic Energy Act of 1954, as amended. In particular, until the two (2) independent Directors are appointed to form the Security Committee, the Chief Executive shall exercise the authority of the Security Committee, except for the authority provided for in Section 5.1(d)(ii)(D) which shall be exercised by the Chairman.
I further acknowledge that the United States Government has placed its reliance on me as a United States citizen to exercise all of the responsibilities provided for in Section 5.1(e) of the Agreement; to assure that members of the NINA Board of Directors, the officers of NINA, and the employees of NINA comply with the provisions of Section 5.1(e) of the Agreement; and to assure that the Nuclear Regulatory Commission is advised of any violation of, attempt to violate, or attempt to circumvent any of the provisions of Section 5.1(e) of the Agreement, of which I am aware.
(j) The Security Committee has the authority to conduct audits to ensure that there is no inappropriate foreign control. This includes the authority to obtain direct access to any employee or contractor personnel involved in the licensing, design, construction and/or operation of STP 3&4.
1D.2.3 Executive Personnel of NINA (a) The CEO of NINA is nominated by NRG Energy, and the Chief Financial Officer is nominated by Toshiba America Nuclear Energy. Given the approximately 90% ownership of NINA by NRG Energy, the NRG Energy Member of the Board of Directors controls the selection of all other officers of NINA. Both the CEO and CNO of NINA must be approved by the Security Committee in accordance with Section 5.1(f) of the NINA LLC Agreement. The NINA CEO, and anyone acting for the NINA CEO, must be a U.S. citizen. The NINA CNO also must be a U.S. citizen.
(b) Section 5.2 of the NINA LLC Agreement provides that, subject to the control of the Board, the CEO and other Executive Personnel shall "have such authority and perform such duties as the Board may
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delegate to them." To the extent authority regarding the affairs of NINA is further delegated by the Board to the CEO and other executive personnel, the CEO assures that U.S. control is maintained over nuclear safety, security and reliability issues.
(c) NINA programs governing security issues, safeguards information, or access to security information are overseen by U.S. citizen managers who report to the CEO. Access and participation in these programs by foreign persons would be permitted only in full compliance with all program requirements. Oversight of these programs and determinations regarding such requirements are and will be subject to U.S. authority and control, because the CEO exercises management authority over such programs, subject only to the ultimate authority of the Security Committee.
(d) In addition, the CNO ensures U.S. control and oversight of nuclear safety issues through control of the Quality Assurance (QA) Program. The VP Oversight reports directly to and is responsible to the CEO. Through QA audits NINA assures that contractors and subcontractors to it and its subsidiaries conduct nuclear safety related activities in accordance with the QA Program, without regard to whether such activities are undertaken by U.S. citizens or by foreign persons, and without regard to whether such activities are performed within the United States or in another country. The requirements of the QA Program assure that all activities are performed consistent with U.S. requirements imposed upon a licensee or applicant for a license. The QA Program also governs activities internal to NINA and its subsidiaries or affiliates. As such, overall control of the QA Program and imposition of QA Program requirements as required by U.S. law and regulation assures that ultimate U.S. control over nuclear safety is maintained without regard to where activities are performed or who performs them.
(e) In the event that any foreign control, domination or influence may be exercised with the potential to disrupt this U.S. control over nuclear safety, security and reliability issues, the NINA CEO would assure U.S. control by taking one or more of the following actions: (1) raising the U.S. control issue with the foreign persons involved and resolving the matter to the satisfaction of the CEO; (2) consulting with the NAC to obtain advice regarding whether or not U.S. control is required and, if so, regarding the appropriate options to consider for resolving the matter consistent with the requirements of the U.S. government; and (3) referring the matter for resolution by the Security Committee. If a matter is referred to the Security Committee by the NAC or the CEO, Section 5.1(e)(iv) of the NINA LLC Agreement requires that the Security Committee conduct a Special Meeting to consider the matter. It is expected that the Security Committee would first decide whether or not the matter is one that must be decided under U.S. control and, if so, the
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Security Committee would vote and decide the matter for the NINA Board.
(f) NINA is not aware of any NINA personnel who currently maintain security clearances with the U.S. government, authorizing their access to classified national security information. It is possible that, in the future, NINA may retain services from contract personnel who obtain or maintain security clearances. However, any such security clearances would be maintained through other companies, which maintain and control their programs to assure compliance with applicable U.S. security requirements and restrict access to such information to only those persons who have been specifically cleared by the U.S. government. The actions of the personnel involved and possession and control of such classified information would be controlled by such other companies and their applicable programs. These programs would not be controlled by NINA, but rather the companies that control these programs would be subject to ongoing oversight by the U.S. government regarding control of these programs free from foreign control, domination or influence. NINA will assure that its personnel comply with all applicable requirements, and it will not provide any directions to its personnel that conflict with their applicable obligations to other companies and their programs regarding such classified information.
(g) In the future, if it becomes necessary or desirable for NINA to maintain its own independent Facility Security Clearance for purposes of governing security clearances to be issued to NINA personnel, NINA would undergo appropriate security reviews prior to being given control (as a corporation) over restricted data or classified national security information. NINA would comply with the requirements of the National Industrial Security Operating Manual, DoD 5220.22-M (February 28, 2006), including the specific applicable requirements relating to foreign ownership, control and influence (FOCI) and submission of the required "Certificate Regarding Foreign Interests" using Standard Form 328 (SF 328). Currently, however, NINA does not exercise any control over access to restricted data or classified national security information.
1D.2.4 Nuclear Advisory Committee (a) NINA has provided for a Nuclear Advisory Committee ("NAC") pursuant to Section 5.1(f) of the NINA LLC Agreement. The NAC will be established prior to any pouring of safety related concrete for STP 3 & 4. The NAC members serve in a non-voting capacity to provide transparency to the NRC and other U.S. governmental authorities regarding FOCD matters impacting NINA. The NAC members serve two year terms and may be reappointed by the Board. Since NRG Energy owns approximately 90% of NINA, the NRG Energy Member of the Board controls the selection and reappointment of the members of
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the NAC. In addition to routine advice to NINA and/or STPNOC (e.g., during operations), the NAC members prepare an annual report to the Board advising on whether NINA is subject to FOCD and whether the Security Committee has been able to exercise its decision-making authority. The NAC also advises whether additional measures should be taken to ensure that NINA and its subsidiaries are in compliance with U.S. laws and regulations regarding FOCD. The CNO shall assure that copies of these reports are submitted to the U.S. Nuclear Regulatory Commission.
(b) NINA will adopt a Charter for the NAC, and the Charter itself will be reviewed from time to time to include revisions and improvements upon the advice of the NAC. The principal purposes of the NAC are to:
Provide transparency to the U.S. Nuclear Regulatory Commission and other U.S. government authorities regarding the implementation of the provisions of Section 5.1(e) of the NINA LLC Agreement providing for authority of the Security Committee over certain matters in order to protect against and negate the potential for any foreign ownership, control or domination of NINA within the within the meaning of 10 CFR 50.38 and Section 103.d of the Act. This includes not only NINA's activities as the licensee responsible for construction, but also the activities of NINA 3 and NINA 4 as owner licensees, including the role of NINA 3 and NINA 4 with respect to the activities of STPNOC as the operating licensee.
Advise and make recommendations to the Board whether measures additional to those already in place should be taken to ensure that: (i) NINA is in compliance with U.S. laws and regulations regarding foreign ownership, control, domination or influence including those related to non-proliferation and fuel cycle matters, and (ii) action by a foreign government or foreign corporation could not adversely affect or interfere with the reliable and safe operations of the nuclear assets of NINA, its subsidiaries, and affiliates ("(i)" and "(ii)" collectively, the "FOCD Matters"), and to provide reports and supporting documentation to the Board relating to such FOCD Matters on at least an annual basis, no later than November 30 of each year. A copy of this report is also provided to the CEO of STPNOC.
(c) The NAC provides ongoing independent assessment of FOCD matters and provides advice to the CEO and the Board regarding FOCD matters. The NAC is available for consultations with the NINA CEO, the STPNOC CEO, or the NINA Security Committee members at any time. However, the NAC also conducts regularly scheduled meetings not less frequently than quarterly. On an ongoing basis, the NAC will report any
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concerns regarding FOCD matters to the CEO and Security Committee in a timely manner.
(d) The NAC members are selected based upon their having substantial expertise in security and nuclear safety matters and ability to serve as a valuable resource to NINA and its senior management in assuring compliance with FOCD requirements.
1D.2.5 NINA's Role as Licensee Responsible for Design and Construction (a) NINA will be the licensee responsible for the design and construction of STP 3 & 4, which will be owned by CPS, NINA 3, and NINA 4. NINA 3 and NINA 4 are entities that are and will be owned and controlled by NINA through its intermediary holding company subsidiaries.
(b) NINA will perform its role pursuant to a licensing, design and construction services agreement with NINA 3 and NINA 4. The licensing, design and construction services agreement will clearly delineate NINA's authority with respect to design and construction, the authority of NINA 3 and NINA 4 with respect to financial decisions, and the obligation of NINA 3 and NINA 4 to pay for the costs of construction. Significantly, these terms will make clear that NINA, as the licensee responsible for design and construction, will have sole authority to make all decisions and to take all actions necessary or useful, with respect to, inter alia, the following:
Any matter relating to nuclear safety, security or reliability, including, but not limited to, the following matters:
(i) Implementation or compliance with any NRC generic letter, bulletin, order, confirmatory order or similar requirement issued by the NRC;
(ii) Prevention or mitigation of a nuclear event or incident or the unauthorized release of radioactive material;
(iii) Placement or restoration of the plant in a safe condition following any nuclear event or incident;
(iv) Compliance with the Atomic Energy Act of 1954 (as in effect from time to time), the Energy Reorganization Act of 1974 (as in effect from time to time), or any NRC rule;
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(v) The obtaining of, or compliance with, a specific license issued by the NRC and its technical specifications;
(vi) Conformance with a specific Final Safety Analysis Report, or other licensing basis document; and
(vii) Implementation of security plans and procedures, control of security information, control of special nuclear material, administration of access to controlled security information, and compliance with government clearance requirements regarding access to Restricted Data.
(c) The above list of matters over which NINA will have sole authority has been formulated in the context of operating reactors, and therefore, some of the above matters may not have full applicability to the construction of STP 3&4. However, the full range of matters is included so as to assure clarity as to NINA's authority as the licensee organization singularly responsible for direction of the design and construction of the proposed plant until such authority is transitioned to STPNOC.
(d) In order to provide greater visibility to management regarding FOCD issues, and the capability of trending FOCD issues, the Corrective Action Program will include a code for identifying any issue that involves potential FOCD concerns.
(e) NINA will assure that the United States Department of Energy, or other agency of the U.S. Government, will either guarantee the loans or loan the funding for at least 50% of the construction funding to be provided through loans. In addition, NINA will assure that U.S. sources will provide at least 50% of the total funding expended to complete construction, whether from loans or from equity contributions.
1D.3 Governance of STP Nuclear Operating Company 1D.3.1 STPNOC Board of Directors (a) STPNOC is a not for profit Texas corporation that is controlled by a board of four directors, three members of which are appointed by Austin, CPS Energy, and NRG South Texas LP, an indirect wholly owned subsidiary of NRG Energy. These three directors choose the fourth director, who then also serves as the CEO of STPNOC. Austin and CPS Energy are governmental organizations in the State of Texas that are controlled by city councils elected by the citizens of these U.S. cities. NRG Energy is a publicly traded, widely held U.S. corporation, and it is not under FOCD.
(b) Pursuant to Article VI of STPNOC's Restated Articles of Incorporation, Austin, CPS Energy and NRG South Texas LP appoint the three
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"Participant Directors" of STPNOC. Notably, NRG South Texas LP is the successor to "Texas Genco LP," which is the entity named in the Restated Articles of Incorporation dated April 27, 2005. The three Participant Directors elect a fourth CEO/Director by a unanimous vote of all three. As such, all of the STPNOC directors currently are U.S. citizens appointed by organizations that are under U.S. control. The STPNOC directors control STPNOC pursuant to Article V of the Restated Articles of Incorporation, which provides that STPNOC "is to have no members," i.e., it has no owners, but rather "its affairs are managed by a Board of Directors."
(c) STPNOC is subject to U.S. control, and it will exercise authority over nuclear safety and security matters free from any potential for foreign domination or control over its decision making in any area of concern to the NRC under 10 CFR 50.38 and Section 103.d of the Act. In particular, STPNOC is and will remain free from any foreign control or domination with regard to security matters, and STPNOC is subject to ongoing U.S. government oversight regarding foreign ownership, control or influence.
(d) STPNOC maintains a Facility Security Clearance, and it has individual employees who maintain U.S. government security clearances. In connection with ongoing oversight of these security clearances, STPNOC periodically updates a "Certificate Regarding Foreign Interests" using Standard Form 328 (SF 328), which provides for disclosures regarding potential foreign ownership, control or influence.
(e) The SF 328 includes various questions regarding a range of potential areas of foreign influence, including debt, foreign source income, foreign directors and executive personnel, contracts and agreements with foreigners, etc. Material changes to answers to any questions in the SF 328 are reported to NRC in accordance with 10 CFR 95.17(a)(1). Submittals to U.S. government security officials include the Department of Energy's forms identifying owners, officers, directors and executive personnel (OODEPs), and their citizenship. These OODEPs are submitted and periodically updated for STPNOC, as well as Austin, CPS Energy and the NRG Energy entities in the chain of control of NRG South Texas LP. Austin, CPS Energy and NRG South Texas LP do not "own" STPNOC, but they are treated like owners in connection with the government's security reviews, because they have the right to appoint the STPNOC Participant Directors.
(f) Notably, neither NINA 3 nor NINA 4 has any rights regarding the appointment of the directors of STPNOC. If NINA 3 and/or NINA 4 acquired rights regarding appointment of directors in connection with their ownership interest in STP 3&4, any such rights would be subject to NRC notice and review requirements, e.g., RIS 2000-01. Moreover, to the extent that NINA, NINA 3 and/or NINA 4 might be in a position to
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control or influence the STPNOC Board, their role with respect to nuclear safety, security or reliability matters is circumscribed by the negation measures described in Section 2.0 of this Plan, including the authority of the Security Committee and the oversight of the Nuclear Advisory Committee to assure that potential FOCD is negated.
1D.3.2 South Texas Project Owners Committee and Operating Agreement (a) The owner licensees for STP 3&4 (CPS Energy, NINA 3, and NINA 4) are members of the South Texas Project Owners Committee, and they have certain rights and decision making authority regarding financial and other matters pursuant to the terms of the Amended and Restated Participation Agreement effective November 17, 1997 (the "Participation Agreement"). As owners of South Texas Project, Units 1 and 2 (STP 1&2), Austin, CPS Energy and NRG South Texas LP are also members of the Owners Committee. Austin, CPS Energy and NRG South Texas LP have certain rights and decision making authority as part of the Owners Committee regarding both STP 1&2 matters and matters common to STP 1&2 and STP 3&4.
(b) The matters to be addressed by the Owners Committee are specified in Section 9.3 of the Participation Agreement, which provides for certain administrative oversight of the South Texas Project by the Owners Committee. To the extent that NINA, NINA 3 and/or NINA 4 may be in a position to indirectly control or influence STPNOC through the participation of NINA 3 and/or NINA 4 in the Owners' Committee, their role with respect to nuclear safety, security or reliability matters is circumscribed by the negation measures described in Section 2.0 of this Plan, including the authority of the Security Committee and the oversight of the NAC to assure that potential FOCD is negated. Thus, if the Owners Committee were to make decisions influencing or implicating nuclear safety, security or reliability issues, then the rights of NINA 3 and/or NINA 4 as part of the Owners Committee would be exercised under U.S. control as provided for in Section 2.0 of this Plan. Moreover, under the terms of the Operating Agreement described further below, STPNOC itself has specific authority that would negate such influence.
(c) Significantly, STPNOC is to be the licensee responsible for operation pursuant to the STP 3&4 licenses. STPNOC has entered into the South Texas Project Operating Agreement dated effective November 17, 1997 (the "Operating Agreement"), and this Operating Agreement governs the terms of its operation of all nuclear generating units at the South Texas Project. Pursuant to the terms of Section 2.1 of the Operating Agreement, STPNOC is granted all requisite authority to exercise its responsibilities as the operating licensee, including having "sole authority" in order "to make all decisions to protect public health and safety as required by the Operating Licenses and applicable laws
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and regulations and as are necessary to comply with applicable laws and regulations." These provisions assure STPNOC control, and therefore "U.S. control," over nuclear safety, security and reliability matters within the meaning of 10 CFR 50.38 and Section 103.d of the Act.
(d) As such, throughout the operation of STP 3&4, STPNOC will have sole responsibility with respect to matters involving nuclear safety, security or reliability, including compliance with all NRC nuclear safety and security requirements (STPNOC's "Sole Authority"). This includes denying unauthorized persons access to security information and assuring compliance with U.S. government requirements governing access to restricted data.
1D.4 Summary (a) This Plan includes a robust set of mechanisms that provide defense in depth to assure that NINA and its licensee subsidiaries, as well as STPNOC, are governed through U.S. control over nuclear safety, security and reliability matters, so that no such entity either is or is expected in the future to be under FOCD within the meaning of 10 CFR 50.38 and Section 103.d of the Act. Under the terms of the NINA LLC Agreement, the ultimate decision making authority of NINA regarding nuclear safety, security and reliability matters has been delegated to the Security Committee, which itself is controlled by independent U.S. citizen directors.
(b) STP 3&4 will be operated by STPNOC, a company that is under U.S. control. In addition, STP 3&4 will be owned 7.625% by CPS Energy, and 92.375% by NINA. NRG Energy owns approximately 90% of NINA, which under the NINA governance gives the NRG Energy Member on the NINA Board of Directors both a majority and supermajority of the votes for matters decided by the NINA Board, including the selection of independent Directors and the NINA CEO and CNO. The NINA CEO and CNO are required to be U.S. citizens who assure that U.S. control is exercised over the management of NINA.
(c) Recognizing that day to day decision making is delegated to executive personnel, the Plan contemplates that a U.S. citizen CEO of NINA will assure U.S. control over matters that require U.S. control. The Plan includes a requirement that the CEO acknowledge a special duty to the U.S. government. In addition, the appointment of any successor CEO must be approved by the Security Committee, which provides additional assurance that the CEO will function as part of the team of U.S. citizens exercising a special duty to the U.S. government to assure compliance with respect to FOCD matters. Significantly, the CEO has access to the expert advice and resources of the NAC and has been given specific authority to refer a matter to the Security Committee, requiring that the Security Committee consider the matter in a Special Meeting. In
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addition, if any person is not satisfied with the resolution of an FOCD concern that is not referred to the Security Committee, that person may raise the issue directly to one or more members of the Security Committee. If any member of the Security Committee agrees that the issue should be brought before the Security Committee, a Special Meeting is required. This assures that even though matters may be delegated to executive personnel, influence over delegated matters cannot be used to circumvent the requirement for U.S. control and the ultimate authority of the Security Committee.
(d) In addition, STPNOC will be the licensee responsible for the operation of STP 3&4. STPNOC is a U.S. company that is under U.S. control. Operation of STP 3&4 is subject to the Sole Authority of STPNOC, as necessary to assure that such operation is not subject to FOCD within the meaning of 10 CFR 50.38 and Section 103.d of the Act. To the extent that NINA, NINA 3 and/or NINA 4 might be able to exercise control or influence over STPNOC, the potential for foreign control, domination or influence over STPNOC regarding nuclear safety, security or reliability matters is mitigated by the negation measures described in Section 2.0 of this Plan.
(e) Notably, Section 3.2(2) of the Standard Review Plan on Foreign, Ownership, Control and Domination specifically provides that further consideration is to be given to "whether the applicant is seeking authority to operate the reactor." STPNOC is the entity to be licensed as the operator, and its role as a U.S. controlled entity that will be responsible for nuclear safety and security throughout the operating life of STP 3&4 should be given great weight in evaluating FOCD issues.
(f) Finally, the NAC will perform an ongoing monitoring function to assess FOCD issues and surface any potential concerns regarding FOCD matters. In addition, the expert resources of the NAC provide a pathway for continuous enhancement and improvement of the mechanisms to assure that any potential inappropriate FOCD is negated. This ongoing role provides further assurance that the required U.S. control of NINA and of the NRC licenses is maintained consistent with the provisions of 10 CFR 50.38 and Section 103.d of the Act.
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1D.5 Implementing Documents 1D.5.1 South Texas Project, Unit 3&4, Negation Action Plan, Rev. 0, dated June 2011. 1D.5.2 South Texas Project, Units 3&4, COLA Part 1, Section 1.5 1D.5.3 Fourth Amended and Restated Operating Agreement of Nuclear Innovation North America, LLC 1D.5.4 Certificates of Independent Directors and CEO
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1E Response to NRC Post-Fukushima Recommendations 1E.1 Introduction In response to the accident at the Fukushima Daiichi Nuclear Power Plant caused by the March 2011, Magnitude 9 Tohoku earthquake and subsequent tsunami, the Nuclear Regulatory Commission established a Near-Term Task Force (NTTF) to review NRC processes and regulations to determine if improvements to its regulatory system were needed. The NTTF developed a set of recommendations intended to clarify and strengthen the regulatory framework for protection against natural phenomena. These recommendations were issued in SECY-11-0093 (Reference 1E-9).
SECY-11-0124 and SECY-11-0137 provided the NRC Commissioners with the Staff’s recommendations, including prioritization for implementation. Subsequently, SECY-12-0025 was issued describing proposed orders to be issued to licensees and a draft request for information pursuant to 10 CFR 50.54(f). SECY-12-0025 stated that combined license plants under review would address the three orders and the request for information through the review process. On March 9, 2012, the Commission issued a Staff Requirements Memorandum (SRM) for SECY-12-0025 (Reference 1E-4) approving issuance of the orders and request for information with some modifications.
This appendix addresses the Tier 1 recommendations and Orders contained in SECY-12-0025, the Tier 2 recommendations contained in SECY-11-0137, and the modifications documented in the SRM consistent with the as issued orders (EA-12-049, 050 and 51) and request for information dated March 12, 2012. The NRC Recommendation in each of the following subsections is a summary of the recommendation from the NRC documents. The response to each recommendation discusses how STP 3 & 4 addresses the recommendation. The numbers in parentheses of subsection headings correspond to the NTTF recommendation number.
1E.2 Tier 1 NRC Recommendation/Responses
1E.2.1 Seismic and Flooding Reevaluations (2.1) 1E.2.1.1 Seismic NRC Recommendation
Perform a reevaluation of the seismic hazards using present-day NRC requirements and guidance to develop a Ground Motion Response Spectrum (GMRS). The new consensus seismic source models from the Central and Eastern United States Seismic Source Characterization (CEUS), NUREG-2115, may be used to characterize the hazards.
Response
Present-day regulatory guidance and methodologies, including the approach described in Regulatory Guide (RG) 1.208, “A Performance Based Approach to Define
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the Site-Specific Earthquake Ground Motion,” were used to evaluate seismic hazards for the STP 3 & 4 site as discussed in Chapters 2 and 3. The evaluation conducted in conformance with RG 1.208 is discussed in Subsection 2.5S.2.6.
STP 3 & 4 reviewed the updated information provided in the CEUS and confirmed that it does not identify any new hazards that are not adequately considered in Chapters 2 and 3, and is not materially different than the GMRS discussed in 2.5S.2.6. Additionally, it was verified that both the existing STP 3 & 4 COLA results and the estimated CEUS SSC results for the STP sites are enveloped by the STP 3 & 4 SSE design spectrum.
1E.2.1.2 Flooding NRC Recommendation
Perform a reevaluation of all appropriate external flooding sources, including the effects from local intense precipitation on the site, probable maximum flood (PMF) on streams and rivers, storm surges, seiches, tsunami, and dam failures. It is requested that the reevaluation apply present-day regulatory guidance and methodologies being used for ESP and COL reviews including current techniques, software, and methods used in present-day standard engineering practice to develop the flood hazard.
The recommendation also noted that flooding risks are of concern because the safety consequences of a flooding event may increase sharply with a small increase in flooding level.
Response
Present-day regulatory guidance and methodologies were used to evaluate flooding hazards relative to the STP 3 & 4 site as discussed in Section 2.4S. Scenarios evaluated include:
Dam Break Analysis (FSAR 2.4S.4)
Main Cooling Reservoir (MCR) Embankment Breach Analysis (FSAR 2.4S.4.2.2)
Probable Maximum Flood on Streams and Rivers (FSAR 2.4S.3)
Local Probable Maximum Precipitation (FSAR 2.4S.2.3)
Probable Maximum Surge and Seiche (FSAR 2.4S.5)
Probable Maximum Tsunami (FSAR 2.4S.6)
Ice Induced Flooding (FSAR 2.4S.7)
Channel Diversions (FSAR 2.4S.9)
Low Water Considerations (FSAR 2.4S.11)
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Conservatisms in the STP 3 & 4 analyses of possible flooding resulting from these events and the plant design minimize the likelihood of even a small increase in flooding level. The postulated MCR embankment breach has been determined to be the design basis flood (DBF) for STP 3 & 4. Very conservative assumptions regarding both the maximum breach size and the speed at which the breech occurs make it highly improbable that the predicted flood level could be exceeded during an actual MCR breach. MCR embankment breach analysis is described in FSAR Subsection 2.4S.4.2.2.
Although the above discussion demonstrates the improbability of a flood exceeding the design basis flood levels, STP 3 & 4 also performed an analysis to determine at what flood level (Cliff Edge) the ability to cool the core would be lost. Although unachievable in any realistic scenario, this level demonstrates the margin beyond design that is built into STP 3 & 4. The flood level that the EDGs would be lost, and therefore, the ability to cool the core would be lost, was determined to be 51 feet.
1E.2.2 Seismic and Flooding Walkdowns (2.3) NRC Recommendations
Perform seismic walkdowns in order to identify and address plant specific degraded, nonconforming, or unanalyzed conditions and verify the adequacy of strategies, monitoring, and maintenance programs such that the nuclear power plant can respond to external events. The walkdown will verify current plant configuration with the current licensing basis, verify the adequacy of current strategies, maintenance plans, and identify degraded, non-conforming, or unanalyzed conditions. The walkdown procedure should be developed and submitted to the NRC. The procedure may incorporate current plant procedures, if appropriate. Prior to the walkdown, licensees should develop acceptance criteria, collect appropriate data, and assemble a team with relevant technical skills.
The NRC also requests that each addressee confirm that they will use the industry developed, NRC endorsed, flood walkdown procedures or provide a description of plant specific walkdown procedures.
Response
This recommendation is not applicable since the STP 3 & 4 units have not yet been built. However, seismic and flooding plant walkdowns will be conducted after construction as documented in COL Information Item 19.9.5.
1E.2.3 Station Blackout (SBO) Rulemaking (4.1) NRC Recommendation
Strengthen the station blackout (SBO) mitigation capability at all operating and new reactors for design-basis and beyond-design-basis events. This includes (1) a minimum coping time of 8 hours for loss of all AC, (2) establishing the equipment, procedures, and training necessary to implement an extended coping time of 72 hours for core and spent fuel cooling and for reactor coolant system and primary containment
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integrity, and (3) pre-planning and pre-staging offsite resources to support uninterrupted core and spent fuel cooling, and RCS and primary containment integrity under conditions involving significant degradation of offsite transportation infrastructure associated with a significant natural disaster. This recommendation will be implemented by rulemaking.
SECY-12-0025 adds the requirement that the loss of the Ultimate Heat Sink (UHS) should be evaluated as part of the SBO evaluation.
Response
(1) The STP 3 & 4 design can withstand an SBO for an indefinite period of time using an alternate AC power source, the Combustion Turbine Generator (CTG), as described in DCD and FSAR Appendix 1C (Table 1C-3). Additionally, the STP 3 & 4 design can withstand a sustained loss of all AC power, including the loss of both CTGs, for 72 hours while maintaining core cooling, as described in DCD Subsection 19E.2.2.3.
The STP 3 & 4 design has a number of features that mitigate an SBO and extended loss of all AC power:
The primary mitigation for an extended SBO is provided by a CTG, which is independent from the Emergency Diesel Generators (EDGs) and can be connected to the 4.16 KV Class 1E buses. This CTG has black start capability and can be available for use within 10 minutes. There is one CTG per unit, they can be crosstied, and one CTG can supply the safety loads for both units. The CTGs are housed in International Building Code structures which are protected from the design basis flood and adverse weather conditions. (DCD Tier 1 Subsection 2.12.11 and DCD and FSAR Tier 2 Appendix 1C).
The batteries have a capacity of 8 hours (DCD Subsection 8.3.2.1.3.1). This capacity can be extended well beyond 8 hours if load shedding is performed.
The Reactor Core Isolation Cooling system can provide core cooling for at least 8 hours during SBO conditions without reliance on AC power (DCD Appendix 19E.2.1.2.2).
The Alternating Current-Independent Water Addition (ACIWA) system is a seismically qualified system with an external permanent diesel-driven pump and water supply capable of providing water to the Residual Heat Removal (RHR) system for core and containment cooling without reliance on AC power. Operation of the ACIWA system is described in DCD Subsection 5.4.7.1.1.10.
Seismically-qualified external connections on opposite sides of the Reactor Building can be used to provide makeup water and sprays to the Spent Fuel Pool (SFP) with the use of staged portable diesel driven water supply pumps as described in Part 11 (Mitigative Strategies Report) Sections 6.1 and 6.2.
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(2) STP 3 & 4 has the installed equipment (e.g., ACIWA system) to implement an extended coping time in excess of 72 hours without reliance on AC power for core and spent fuel cooling and for reactor coolant system and primary containment integrity as documented in Subsection 19E.2.2.3. The 72 hours of core cooling can be provided without reliance on the UHS. Relevant procedures and training will be developed per the Operational Program Development Plan described in FSAR Section 13.4S and DCD and FSAR Section 13.5.
(3) Pre-planning and pre-staging resources to support uninterrupted core and spent fuel pool cooling, and RCS and primary containment integrity under conditions involving significant degradation of the onsite facilities associated with large fires and explosions are documented in Part 11. Additionally, as discussed in the next section, STP will arrange for sufficient offsite resources to sustain core, containment, and spent fuel pool cooling indefinitely. These plans and resources will provide this capability under circumstances involving significant degradation of offsite transportation infrastructure associated with a significant natural disaster.
Detailed procedures and training associated with strengthening SBO mitigation capabilities in accordance with the SBO Rule will be developed during implementation of operational programs as described in FSAR Section 13.5.
1E.2.4 Mitigating Strategies for Beyond Design Basis Events (4.2) NRC Recommendation
NRC issued Order EA-12-049 (Reference 1E-5) to power reactor licensees and holders of construction permits requiring a three-phase approach for mitigating beyond-design-basis external events. The initial phase requires the use of installed equipment and resources to maintain or restore core cooling, containment and spent fuel pool (SFP) cooling capabilities. The transition phase requires providing sufficient, portable, onsite equipment and consumables to maintain or restore these functions until they can be accomplished with resources brought from offsite. The final phase requires obtaining sufficient offsite resources to sustain those functions indefinitely.
Response
STP 3 & 4 incorporates three staged AC independent portable pumping systems:
Two pumps (a fire truck and a trailer mounted portable pump) shared between STP 3 & 4 provide core, SFP, and containment cooling water to the RHR system via the ACIWA system. Operation of the ACIWA system is discussed in DCD Subsection 5.4.7.1.1.10.
– The fire truck is stored in the Turbine Building Truck Bay and is protected from site hazards with the exception of floods.
– The trailer mounted portable diesel-driven pump is stored in a Seismic Category I structure as required for protection from severe weather events (FSAR Subsection 19.4.6). In addition, one of the two diesel driven pumps to
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be procured in accordance with FLEX guidance will be stored in a Seismic Category I structure. These pumps will be included in the DRAP.
One trailer mounted pump shared between STP 1, 2, 3, & 4 provides water in the event of the loss of large areas of the plant (Part 11, Subsection 5.1.2).
– This trailer mounted pump is protected primarily by distance.
In addition to the above pumps, two additional portable high capacity pumps will be procured as described in the paragraph below. This will result in one high capacity portable trailer mounted diesel driven pump stored in a Seismic Category I structure in each unit, two fire trucks stored in a turbine building, and one trailer mounted diesel driven pump shared between the four units.
Additional equipment to be procured to provide defense in depth mitigation capability includes:
Two diesel driven high capacity pumps (one/unit) one of which will be required to be kept in a Seismic Category I structure
Six portable diesel generators (three/unit)
Four portable DC power supplies (two/unit)
Eight handheld satellite phones (four/unit)
Various hoses, fittings, cables, and jumpers necessary to connect the above equipment
The STP 3 & 4 approach for mitigating a Beyond Design Basis External Event (BDBEE) is described in Reference 1E-14, STP 3&4 ABWR FLEX Integrated Plan. This plan is patterned after the industry FLEX program (Reference 1E-3). This industry program was endorsed by the NRC (with comments) in Reference 1E-13.
The STP 3 & 4 FLEX Integrated Plan provides guidance and strategies to restore core cooling, containment cooling, and spent fuel cooling following a BDBEE involving one or both STP 3 & 4 units. The strategies are capable of mitigating a simultaneous loss of all alternating current (ac) power (including both CTGs) and loss of normal access to the ultimate heat sink, and are capable of being implemented in all operating modes. The equipment required to mitigate the BDBEE will be adequately protected from external events.
The guidance utilizes a two-phase approach.
Phase 1 uses installed equipment and resources to maintain or restore core, containment, and spent fuel pool (SFP) cooling capabilities. Phase 1 will be 36 hours in length. Since the FLEX equipment can be delivered from the offsite Regional Response Center to the site within 32 hours, there is no need for a Phase
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2 using onsite portable equipment and there is a direct transition from Phase 1 to Phase 3 at 36 hours.
The final phase 3 will obtain sufficient offsite resources to sustain the core cooling, containment cooling, and spent fuel cooling functions indefinitely.
As described in the introduction to the STP 3&4 FLEX Integrated Plan, the plan does not take credit for the Combustion Turbine Generators (CTGs) that are part of the STP 3&4 design, even though it is believed that one, if not both, would survive a BDBEE and would clearly be the initial approach in responding to such an event. The FLEX Plan as described in Reference 1E-14 credits the installed Reactor Core Isolation Cooling (RCIC), AC Independent Water Addition (ACIWA), and the Containment Overpressure Protection (COPS) systems to provide core, containment, and spent fuel cooling during Phase 1 and Phase 3 in accordance with the NRC Order.
To support the implementation of the FLEX Plan, the following system design requirements will be incorporated into the STP Units 3&4 final design:
RCIC piping expansion calculations will be performed at 250°F.
The CTGs will be protected from design basis hurricane and tornado missiles.
Battery jumper connections will be installed and normally disconnected cabling will be installed as necessary to allow the four divisions of the Class 1E 125 VDC battery systems to be connected to the Division 1 battery bus to provide extended 125 VDC power.
The Condensate Storage Tank (CST) for each unit will be constructed to withstand the site-specific Safe Shutdown Earthquake (SSE) of 0.13g, missile, flood, high wind and other site specific severe weather hazards.
The ACIWA System (including the fuel supply tank) will be protected against site flood and severe weather events. The ACIWA diesel fuel storage tank will have sufficient storage capacity to support 36 hours of operation for both units.
Both Fire Water Storage Tanks will be constructed to withstand the site-specific SSE of 0.13g, missile, flood, high wind, and other site specific severe weather events.
Permanent piping to allow the ACIWA System to take suction from the water volume in the UHS Basins will be sub-surface piping installed during plant construction with the appropriate separation of safety related and non-safety related systems. This piping will be robust and consistent with the design requirements of the ACIWA system (Reference DCD Subsection 19I.4).
One plant stack radiation monitor will be powered by Division 1E power
Internal plant radio communications will be powered by the non-Class 1E 250 VDC battery located in the Control Building for at least 36 hours. The non-Class 1E
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battery will be constructed to withstand the site-specific Safe Shutdown Earthquake (SSE) of 0.13g, missile, flood, high wind and other site specific severe weather hazards.
Permanent electrical connections will be installed to allow the Phase 3 FLEX 480V 1500 kW DGs to be connected outside the Reactor Building and provide power to ESF Load Centers. The input circuit breaker from the 4160/480 VAC transformer to the applicable 480VAC power centers will be opened to isolate the FLEX DGs from the rest of the safety related distribution system.
The detailed procedures and training to support the FLEX Program will be developed during implementation of Operational Programs as discussed in FSAR Section 13.4S in cooperation with STP Units 1 & 2 as a 4 unit site. Personnel will be trained to perform the job specific functions necessary for their assigned tasks. The Systematic Approach to Training will be used to determine the initial and continuing elements of required training as well as the population to be trained.
1E.2.5 Reliable Hardened Vents (5.1) NRC Recommendation
NRC issued an Order to operating Boiling-Water Reactor (BWR) licensees with Mark I and Mark II containments requiring them to have a reliable hardened vent to remove decay heat and maintain control of containment pressure within acceptable limits following events that result in the loss of active containment heat removal capability or prolonged Station Blackout (SBO). The hardened vent system is required to be accessible and operable under a range of plant conditions, including a prolonged SBO and inadequate containment cooling.
Response
This recommendation does not apply since STP 3 & 4 does not have a Mark I or Mark II containment.
However, each STP 3 & 4 unit does have a passive, reliable hardened vent as part of the Containment Overpressure Protection System (COPS). COPS is Seismic Category I and is qualified for accident pressures. The vent paths for the units are not shared. This design is described in DCD and FSAR Subsection 6.2.5.2.6 and its use in conjunction with long term cooling without AC power to prevent fuel damage is demonstrated in DCD Appendix 19E.2.2.
1E.2.6 Spent Fuel Pool (SFP) Instrumentation (7.1) NRC Recommendation
NRC issued an order to power reactor licensees and holders of construction permits requiring them to have a reliable indication of the water level in associated spent fuel storage pools capable of supporting identification of the following pool water level conditions by trained personnel: (1) level that is adequate to support operation of the normal fuel pool cooling system, (2) level that is adequate to provide substantial
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radiation shielding for a person standing on the spent fuel pool operating deck, and (3) level where fuel remains covered and actions to implement make-up water addition should no longer be deferred.
Response
The certified ABWR design includes reliable level and temperature monitors in the SFP that provide indication and annunciation via the process computer in the Main Control Room (MCR). Additionally, STP 3 & 4 SFP level indication independent of the process computer will be provided at the remote shutdown system panel or other appropriate and accessible location. The instruments will be powered by Class 1E batteries. Although not Post Accident Monitoring (PAM) instruments, the SFP level instrumentation channels will be designed and qualified to PAM Category 1 requirements (see DCD, Section 7.5).
STP 3 & 4 will also enhance the spent fuel pool instrumentation to ensure that it provides a reliable indication of the water level in the spent fuel storage pools capable of supporting identification of the following pool water level conditions by trained personnel: (1) level that is adequate to support operation of the normal fuel pool cooling system, (2) level that is adequate to provide substantial radiation shielding for a person standing on the spent fuel pool operating deck, and (3) level where fuel remains covered and actions to implement make-up water addition should no longer be deferred. These enhancements will be consistent with the guidance provided in NEI 12-02, Revision 1 (Reference 1E-11), and JLD-ISG-2012-03 (Reference 1E-12).
1. The spent fuel pool level instrumentation will include the following design features:
1.1 Instruments: The instrumentation will consist of two permanent, fixed instrument channels with level indication from the top of the fuel racks to above the normal operating level of the spent fuel pool. Level instrumentation will include high and low water level alarms that annunciate in the Control Room and level indication independent of the process computer at the remote shutdown system panel or other appropriate and accessible location. The level channels will be functional in all plant operating modes.
1.2 Arrangement: The spent fuel pool level instrument channels will be arranged in a manner that provides reasonable protection of the level indication function against missiles that may result from damage to the structure over the spent fuel pool. This protection will be provided by maintaining instrument channel separation within the spent fuel pool area, and will utilize inherent shielding from missiles provided by existing corners in the spent fuel pool structure. The channel separation guidance contained in NEI 12-02, Revision 1 Section 3.2 will be considered in determining sensor locations.
1.3 Mounting: Installed instrument channel equipment within the spent fuel pool will be mounted to retain its design configuration during and following the maximum seismic ground motion considered in the design of the spent fuel pool structure. The seismic design of the mounting will be consistent with the
Response to NRC Post-Fukushima Recommendations 1E-9 Rev. 12 STP 3 & 4 Final Safety Analysis Report
SFP seismic design and will include an evaluation of other hardware stored in the SFP to ensure it will not create adverse interaction with the fixed instrument locations.
1.4 Qualification: The instrument channels will be reliable at temperature, humidity, and radiation levels consistent with normal operation, event, and post-event conditions. This reliability will be established through use of an augmented quality assurance process (e.g., a process similar to that applied to the site fire protection program). Verification that the instrument channel design and installation is adequate from shock and vibration and seismic perspectives will be demonstrated as discussed in NEI 12-02, Revision 1 and JLD-ISG-12-03. In addition, these instrument channels will be included in the Design Reliability Assurance Program (DRAP).
1.5 Independence: The instrument channels will be physically and electrically independent of each other.
1.6 Power supplies: The level instrumentation channels will be powered by separate Class 1E batteries. The STP 3 & 4 Class 1E batteries are capable of providing 125 VDC power for over 76 hours post-event utilizing deep load shedding and division cross-connection strategies.
FLEX equipment is expected to arrive on site approximately 32 hours after event initiation. At this time, 480 VAC FLEX diesel generators will be installed and used to power the battery chargers and other select ESF loads, thereby assuring battery functionality indefinitely.
In addition, the instrument channel design will provide for quick and accessible power connections from alternate sources independent of the plant AC and DC power distribution systems. This design will also allow for isolating the instrument channels from their normal power supplies. The independent alternate sources used for instrument channel power will have sufficient capacity to maintain the level indication function until offsite resource capability is reasonably assured. These power supplies will be stored in diverse robust structures.
1.7 Accuracy: The instrument channels will maintain their designed accuracy following a power interruption or change in power source without recalibration. Considerations in determining required instrument accuracy should include SFP conditions, e.g., saturated water or steam conditions. Instrument accuracy will also be sufficient to allow trained personnel to determine when the actual level reaches the specified lower level of each indicating range (Levels 1, 2 and 3) without conflicting or ambiguous indication.
1.8 Testing: The instrument channel design will provide for routine testing and calibration which can be accomplished in-situ.
1E-10 Response to NRC Post-Fukushima Recommendations Rev. 12 STP 3 & 4 Final Safety Analysis Report
1.9 Display: Trained personnel will be able to monitor the spent fuel pool water level from the control room and either in the vicinity of Remote Shutdown System room or other appropriate and accessible location. The display will provide on-demand or continuous indication of spent fuel pool water level.
2. The spent fuel pool instrumentation will be maintained available and reliable through appropriate development and implementation of the following programs:
2.1 Training: Personnel will be trained to perform the job specific functions necessary for their assigned tasks (maintenance, calibration, surveillance, etc.) including the use and the provision of alternate power to the instrument channels. The Systematic Approach to Training will be used to determine the initial and continuing elements of required training as well as the population to be trained.
2.2 Procedures: Procedures shall be established and maintained for the testing, calibration, and use of the spent fuel pool level instrument channels. These procedures will also address any known potential abnormal response issues associated with the instrumentation.
2.3 Testing and Calibration: Processes will be established and maintained for scheduling and implementing necessary testing and calibration of the spent fuel pool level instrument channels to maintain the instrument channels at the design accuracy. Additionally, the out of service provisions contained in NEI 12-02, Revision 1, Section 4.3 will be implemented for the SFP level channels. The spent fuel pool level instrument channels will be included in the Design Reliability Assurance Program (DRAP).
1E.2.7 Emergency Procedures Rulemaking (8.0) NRC Recommendation
Strengthen and integrate onsite emergency response capabilities such as emergency operating procedures (EOPs), severe accident management guidelines (SAMGs), and extensive damage mitigation guidelines (EDMGs). This includes modification of Technical Specifications to reference the approved EOP technical guidelines and providing more realistic, hands-on training on SAMGs and EDMGs.
Response
STP 3 & 4 procedure development will integrate the EOPs, SAMGs, and EDMGs by using the following guidance:
Industry (BWROG) guidance as endorsed by applicable NRC regulatory guides consistent with the Task Force recommendation (SECY-11-0124).
Plant Specific Technical Guidelines (PSTGs), EOPs and SAMGs development activities using as inputs the standard ABWR guidelines (DCD and FSAR Sections 13.5 and 1A.2) and generic industry guidance per NEI 91-04, Revision 1, Severe Accident Issue Closure Guidelines, which includes the industry commitment to
Response to NRC Post-Fukushima Recommendations 1E-11 Rev. 12 STP 3 & 4 Final Safety Analysis Report
incorporate severe accident strategies into the overall accident management program.
EDMGs development as described in NEI 06-12 (Mitigative Strategies Report).
Chapter 13 describes the procedure development plan.
The STP 3 & 4 Technical Specifications meet the requirement to reference the approved EOP Guidelines. (Technical Specifications 5.5.1.1.b)
Training development requirements in DCD and FSAR Section 13.2 and FSAR Section 13.4S will meet the applicable requirements for realistic hands-on training.
1E.2.8 Enhanced Emergency Plan Staffing and Communication (9.3) NRC Recommendation
Assess current communications systems and equipment used during an emergency event assuming the potential onsite and offsite damage as a result of a large scale natural event resulting in a loss of all alternating current (AC) power It is also requested that consideration be given to any enhancements that may be appropriate for the emergency plan with respect to communications requirements of 10 CFR 50.47, Appendix E to 10 CFR Part 50, and the guidance in NUREG-0696 in light of the assumptions stated above. Also consider the means necessary to power the new and existing communications equipment during a multi-unit event, with a loss of all AC power.
Assess current staffing levels and determine the appropriate staff to fill all necessary positions for responding to a multi-unit event during a beyond design basis natural event and determine if any enhancements are appropriate given the considerations of NTTF Recommendation 9.3.
Response
The Emergency Plan for STP 3 and 4 will be part of a site-wide emergency plan for Units 1 through 4. NEI 12-01 (Guidelines for Assessing Beyond Design Basis Accident Response Staffing and Communications Capabilities) will be used in assessing staff and communications capabilities necessary to respond to a beyond design basis multi- unit event. The results of the assessment will be addressed in the detailed Emergency Plan procedures developed during implementation of operational programs as described in FSAR Section 13.4S and in concert with STP Units 1 and 2. COLA Part 9 Table 4.0-1, Item 10 lists the ITAAC applicable to the Emergency Plan and implementing procedures.
1E.3 Tier 2 NRC Recommendations/Responses 1E.3.1 Other Natural External Hazards (2.1) NRC Recommendation
1E-12 Response to NRC Post-Fukushima Recommendations Rev. 12 STP 3 & 4 Final Safety Analysis Report
Reevaluate and upgrade as necessary the design basis of structures, systems, and components important to safety for protection against natural external hazards other than seismic and flooding.
Response
The hazards and natural phenomena potentially affecting the STP 3 & 4 site have been identified, screened and evaluated in accordance with the latest revisions of the Standard Review Plan. The review and conclusions are documented in Chapters 2 and 3 along with the appropriate design features necessary to mitigate the events. The natural events of particular interest at the STP site are hurricane wind and missiles. STP 3 & 4 meets the latest regulatory guidance document (RG 1.221) for hurricane winds and missiles, which is based on an extreme hurricane (FSAR Subsections 2.3S.1.3.3.2 and 3H.11).
1E.3.2 Safety-related AC electrical power for the SFP makeup system (7.2) NRC Recommendation
NRC to issue an order requiring safety related AC power for the SFP makeup system.
In accordance with SECY-11-0137, Recommendation 7.2 will be implemented by rulemaking to provide reliable SFP instrumentation and makeup capabilities
Response
The STP 3 & 4 design provides emergency makeup to the SFP using any of the three trains of the RHR system, which are powered by safety-related AC power (FSAR Subsection 2.4.1).
1E.3.3 Technical Specifications requirement for onsite emergency power (7.3) NRC Recommendation
NRC to issue an order to revise technical specifications to require that one train of onsite emergency power be operable for SFP makeup and instrumentation whenever spent fuel is in the SFP, regardless of the operational mode of the reactor.
In accordance with SECY 11-0137, Recommendation 7.3 will be implemented by rulemaking to provide reliable SFP instrumentation and makeup capabilities.
Response
The STP 3 & 4 Technical Specifications require at least one Emergency Diesel Generator and one Residual Heat Removal (RHR) pump to be operable in all modes. The safety related RHR system is backed by the emergency diesel generators and can also be powered by the Combustion Turbine Generator. The RHR system is capable of providing makeup to the SFP.
Response to NRC Post-Fukushima Recommendations 1E-13 Rev. 12 STP 3 & 4 Final Safety Analysis Report
1E.3.4 Spent Fuel Pool Spray (7.4) NRC Recommendation
NRC to issue order requiring seismically qualified means to spray water into the spent fuel pools, including an easily accessible connection to supply the water (e.g., using a portable pump or pumper truck) at grade outside the building
In accordance with SECY 11-0137, Recommendation 7.4 will be implemented by rulemaking to provide reliable SFP instrumentation and makeup capabilities
Response
STP 3 & 4 has committed to install a diverse spent fuel pool makeup and spray system as described in Part 11 (Mitigative Strategies Report), Section 6.0 that meets the criteria specified in this recommendation
1E.4 DC Electrical Equipment Loading Considerations As discussed in Section 2.4 of this appendix, the ability of the Division 1 safety-related battery was evaluated to support the required loads during Phase 1 of an ELAP. In order to extend the time the safety related batteries can support an extended station blackout (SBO) required loads, a battery analysis was performed which includes deep load shed of each Divisional battery with the following loads remaining: Division I Remote Shutdown Panel; Division I Reactor and Control building lighting; Division I safety relief valves (SRV); and Division I RCIC valves. The deep load shed will be completed by procedure within one hour by operators; therefore, the duty cycle for the first hour is assumed to be the normally connected DC loads. The duty cycle after one hour is a constant load for the Remote Shutdown panel, Reactor and Control building lighting and SRVs (conservatively considered to be constantly energized). The RCIC valves are assumed to be cycled open and closed periodically throughout the scenario.
The required duty cycle for the extended SBO analysis will be longer than the typical battery discharge information provided by battery vendors. However, battery vendors have tested their batteries for longer discharge cycles and vendor published data for extended discharge lengths was used in the extended SBO analysis.
The battery sizing analysis for an extended station blackout scenario uses the methodology given in IEEE 485, ‘Recommended Practice for Sizing Lead-Acid Batteries for Stationary Applications.’ The methodology is used to determine the length of time the divisional batteries can provide adequate voltage and power to the needed DC loads.
The minimum acceptable battery voltage to run all safety related loads has been determined by the Class 1E battery sizing and voltage drop calculation. The analysis determines the minimum voltage that the battery needs to provide and the allowable voltage drops between the battery and various end loads. The extended SBO analysis uses the same minimum battery voltage to size the battery and ensure adequate voltage is provided to the end loads.
1E-14 Response to NRC Post-Fukushima Recommendations Rev. 12 STP 3 & 4 Final Safety Analysis Report
1E.5 References 1E-1 SECY-11-0137, “Prioritization of Recommended Actions to be taken in response to Fukushima Lessons Learned” October 3, 2011.
1E-2 SECY-12-0025, “Proposed Orders and Requests for Information in Response to Lessons Learned From Japan’s March 11, 2011, Great Tohoku Earthquake and Tsunami”.
1E-3 NEI 12-06 [Revision 0] "Diverse and Flexible Coping Strategies (FLEX) Implementation Guide" August, 2012.
1E-4 SRM for SECY 12-0025, “Staff Requirements-SECY-12-0025 Proposed Orders and Requests for Information in Response to Lessons Learned from Japan’s March 11, 2011, Tohoku Earthquake and Tsunami” March 9, 2012.
1E-5 EA-12-049, “Issuance of Order to Modify Licenses with Regard to Requirements for Mitigation Strategies for Beyond Design-Basis External Events,” March 12, 2012.
1E-6 EA-12-050, “Issuance of Order to Modify Licenses with Regard to Reliable Hardened Containment Vents” March 12, 2012.
1E-7 EA-12-051, “Issuance of Order to Modify Licenses with Regard to Reliable Spent Fuel Pool Instrumentation,” March 12, 2012.
1E-8 NUREG-2115, “Central and Eastern United States Seismic Source Characterization”.
1E-9 SECY-11-0093, “The Near-Term Report and Recommendations for Agency Actions Following the Events in Japan,” July 12, 2011.
1E-10 NEI 12-01, Guidelines for Assessing Beyond Design Basis Accident Response Staffing and Communications Capabilities.
1E-11 NEI 12-02 [Revision 1] “Industry Guidance for Compliance with NRC Order EA-12-051, “To Modify Licenses with Regard to Reliable Spent Fuel Pool Instrumentation” August 2012.
1E-12 JLD-ISG-2012-03 “Compliance with Order EA-12-051, “Reliable Spent Fuel Pool Instrumentation” August 29, 2012.
1E-13 JLD-ISG-2012-01 [Revision 0] "Compliance with Order EA-12-049, Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design Basis External Events" August 29, 2012.
1E-14 STP 3&4 ABWR FLEX Integrated Plan.
Response to NRC Post-Fukushima Recommendations 1E-15/16
Rev. 12
STP 3 & 4 Final Safety Analysis Report
2.0 Site Characteristics The information in this section of the reference ABWR DCD, including all tables, is incorporated by reference with the following departures and site-specific supplements.
STD DEP T1 2.15-1 (Table 2.0-2)
STP DEP 9.4-8 (Table 2.0-2)
Supplemental Table 2.0-2 provides a comparison of the reference ABWR DCD design parameters with the actual STP 3 & 4 site characteristics. A column is provided indicating whether or not the site-specific parameters are bounded by the ABWR Standard Plant Site Design Parameters. Another column provides a discussion of those values that are not bounded, with a basis for any departure from the reference ABWR DCD design. The "Discussion" column also provides a roadmap to the FSAR sections where further information is provided.
Site Characteristics 2.0-1 Rev. 12
STP 3 & 4 Final Safety Analysis Report Further information on extreme winds is winds extreme on information Further characteristic is 6 ft below nominal finished nominal below is 6 ft characteristic maximum on information Further grade. plant in Subsection level is provided groundwater 2.4S.12. in Subsection 2.3S.1. provided STP for the wind speed hurricane Maximum with accordance in determined was Site in described as 1.221 Guide Regulatory 2.3S.1.3.3.2. Subsection was missile spectrum generated Hurricane determined in accordance with Regulatory in Subsection as described 1.221 Guide 3H.11. (Yes/No) Discussion Bounded Yes Not Applicable 4 Site Characteristics 338 km/h (210 mph) for 3-second wind 3-second for mph) km/h (210 338 201 km/h/215 km/h wind 3-second for mph) mph/134 (125 gust gust Design Parameters STP 3 & ABWR Standard Plant Site Site Plant ABWR Standard None 177 km/h [1] /197 km/h [2] 3.3.1.1, the Section Per ABWR DCD basic reference wind speed corresponds50-a to year/100-year wind velocity (3- second wind gust) of: km/h/224 km/h 203 mph) mph/139 (126 61.0 cm (2 ft) below below grade ft) cm (2 61.0 MSL ft 28 Yes site level groundwater Maximum Table 2.0-2 Comparison of ABWR Standard Plant Site Design Parameters and STP 3 & 4 Site Characteristics Site Characteristics and STP 3 & 4 Parameters Plant Site Design of ABWR Standard Comparison 2.0-2 Table Subject STP Site Hurricane Speed Wind and Missiles [12] Extreme WindExtreme Basic Speed: Wind Maximum Maximum Water Ground Level
2.0-2 Site Characteristics Rev. 12
STP 3 & 4 Final Safety Analysis Report design basis flood level level is basis flood design MSL (MSL above cm) (1219.2 40.0 ft NVGD29). This level is based on the breach Main Cooling Reservoir (MCR) of the 6.0 of approximately level a flood in resulting grade, plant nominal above cm) (182.9 ft STP MSL (see cm) (1036.3 is 34 ft which DEP T1 5.0-1). STP 3 & 4 safety-related structures, are (SSCs) systems, components and this flooding from or protected for designed entry the to prevent doors watertight by event of water into the Reactor Buildings and Flooding flood. of a in case Buildings Control due to the maximum requirements protection flood level are discussedSectionin 3.4. PRA flooding external an addition, In the that for STP 3 & 4 concluded analyses low is acceptably flooding risk external from 19R. in Section as discussed (Yes/No) Discussion Bounded No 2.4S.4, the As discussed in Subsection 4 Site Characteristics grade Design Parameters STP 3 & ABWR Standard Plant Site Site Plant ABWR Standard 30.5 cm (1 ft) below30.5 cm gradeft) (1 182.9 above(6.0 cm ft) nominalplant Table 2.0-2 Comparison of ABWR Standard Plant Site Design Parameters and STP 3 & 4 Site Characteristics (Continued) STP 3 & 4 Site Characteristics and Parameters Site Design Plant of ABWR Standard Comparison 2.0-2 Table Subject Maximum Maximum Flood (or Tsunami) Level [8]
Site Characteristics 2.0-3 Rev. 12
STP 3 & 4 Final Safety Analysis Report provided in Subsection in Subsection 2.3S.1. provided 3.5.1.4. in Subsections provided (Yes/No) Discussion Bounded Yes is spectra missile on information Further 4 Site Characteristics 322 km/h (200 mph) km/h (200 322 mph) km/h (160 257 km/h64 (40 mph) ft) (150 45.7m Yes6.2 kPaD(0.9 psi) Yes is parameters tornado on information Further (0.4 psi/sec)2.8 kPa/sec Yes fromspectrumRegion II missile Revision 1. 1.76, Guide Regulatory Yes Yes Yes Design Parameters STP 3 & ABWR Standard Plant Site Site Plant ABWR Standard Maximum Rotational Speed: Speed: Rotational Maximum mph) km/h (240 386 Velocity: Translational mph) (60 km/h 97 Radius: ft) m (150 45.7 Drop: Pressure Maximum psi) (2.0 kPaD 13.827 Rate of Pressure Drop: psi/sec) kPa/s (1.2 8.277 Missile Spectra: I [4] Spectrum 483 km/h (300 mph) km/h (300 483 Table 2.0-2 Comparison of ABWR Standard Plant Site Design Parameters and STP 3 & 4 Site Characteristics (Continued) STP 3 & 4 Site Characteristics and Parameters Site Design Plant of ABWR Standard Comparison 2.0-2 Table Subject Tornado Wind Speed: Tornado Maximum
2.0-4 Site Characteristics Rev. 12
STP 3 & 4 Final Safety Analysis Report of water cannot cannot of water will not affect willthe not affect will not result in a tion 3H.6.4.3.3.5. is provided in Subsec Plant of ABWR Standard height Parapet structures will be limited to 9 inches. The maximum rainfall rate is used as one one as is used rate rainfall maximum The factordeterminingin the structural loading of the A review roof design. for conditions 2 Appendices ABWR DCD Tier reference ABWR that standard 3H.2 indicates 3H.1and Seismic Category I structures have roofs with scuppers or parapets parapets without so that large drains roof to supplement cannot of precipitation inventories the that 3H.6accumulate. states Appendix roof of the site-specific Seismic Category I structures (i.e. reactor service water pump so parapets without designed are houses) ponding excessive that in exceedance cm/hr 1 the Therefore, occur. maximum rainfall rate design roof in the increase substantial loading; and therefore, structures. of design these specific maximum rainfall rate is 50.3 cm/h the DCD exceeds which in/hr), (19.8 (see parameter site design plant standard STP DEP T1 5.0-1). Further information on maximum snow load load snow maximum on information Further (Yes/No) Discussion Bounded No Yes ation roof load = load ation roof 4 Site Characteristics Normal roof snow load = 6.6 psf and and = 6.6 psf snow load roof Normal Extreme winter precipit 47 psf Design Parameters STP 3 & ABWR Standard Plant Site Site Plant ABWR Standard 2.394 kPa (50 psf) kPa (50 2.394 Maximum Snow Load: Load: Snow Maximum 49.3 cm/h (19.4 in/hr) [3] in/hr) (19.4 cm/h 49.3 in/hr) (19.8 cm/h 50.3 Maximum Rainfall Rate: site- 2.4S.2, the As discussed in Subsection Table 2.0-2 Comparison of ABWR Standard Plant Site Design Parameters and STP 3 & 4 Site Characteristics (Continued) STP 3 & 4 Site Characteristics and Parameters Site Design Plant of ABWR Standard Comparison 2.0-2 Table Subject Precipitation Precipitation (for Roof Design)
Site Characteristics 2.0-5 Rev. 12
STP 3 & 4 Final Safety Analysis Report design to determine to determine design Based on a review of the reference ABWR of the reference a review Based on Building Control 9.4, the 2 Section DCD Tier and Reactor Building Safety Related HVAC, systems are Electrical Equipment HVAC maximum summer outdoor an for designed temperature of 46°C. This temperature ABWR 0% exceedance to the corresponds value.The ABWR 0% exceedance state STP 0% the site-specific bounds point 1% and the point state exceedance the Therefore, point. state exceedance reference ABWR DCD cooling loads values exceedance 0% on based calculated Reactor and HVAC, Building Control for Electrical Equipment Related Safety Building systems are bounding. Therefore,HVAC the bulb wet in 1% exceedance change temperature has no adverse impact on these systems. HVAC combination with coincident wet-bulb temperature provides the state point is used as design that the air) of (enthalpy system input for HVAC cooling loads. The 1% exceedance STP bounded not is value point state site-specific point ABWR state 1% exceedance by the 5.0-1). DEP T1 STP (see systems are HVAC Nonsafety-related summer outdoor on based designed temperatures of 32.8°C dry bulb and 26.3°C wet bulb (coincident) and outdoor winter temperature of2.1°C bulb. dry (Yes/No) Discussion Bounded No No 4 Site Characteristics 2.1°C (35.8°F) [9] dry-bulb44.1°C (111.3°F) 22.4°C (72.4°F) wet-bulb (coincident) Yes Yes Yes 27.3°C (81.2°F) wet-bulb (non-coincident) 32.8°C (91°F) dry-bulb [9]26.3°C (79.3°F) wet-bulb (coincident) [9] Yes 1% Exceedance Values Exceedance 1% in temperature dry-bulb maximum The 0% Exceedance Values (Historical limit) 0% Exceedance Values Design Parameters STP 3 & ABWR Standard Plant Site Site Plant ABWR Standard Minimum: (-9.9°F) -23.3°C Maximum: 26.7°C (80°F) wet-bulb (coincident) Maximum: Maximum: dry-bulb (115°F) 46.1°C Maximum: 26.7°C (80°F) wet-bulb (non-coincident) Maximum: dry-bulb (100°F) 37.8°C Maximum: wet-bulb (77°F) 25°C (coincident) Table 2.0-2 Comparison of ABWR Standard Plant Site Design Parameters and STP 3 & 4 Site Characteristics (Continued) STP 3 & 4 Site Characteristics and Parameters Site Design Plant of ABWR Standard Comparison 2.0-2 Table Subject Ambient Design Temperature
2.0-6 Site Characteristics Rev. 12
STP 3 & 4 Final Safety Analysis Report The non-safety relatedReactor Building system has HVAC Containment Secondary can of the changes Details redesigned. been Radwaste The 9.4. in Chapter be found Radwaste of the some Building, Radwaste the and systems, Management been have systems HVAC Building changes of these details Further redesigned. 9.4. Chapter and 11 Chapter in found be can systems are HVAC Building The Radwaste to designed have been and STP specific and temperatures ambient STP site-specific design is compliant with the revised HVAC Characteristics. STP 3&4 is wet-bulb non-coincident maximum The of performance short-term for input used as cooling towers. In the case of STP 3 & 4, this the 30-day for point data is an hourly value site-specific analysis. The evaporation wet-bulb non-coincident maximum not are basis an hourly on temperatures ABWR site by the reference bounded 30-day calculated the However, parameters. non- maximum consecutive 24-hour and been have temperatures wet-bulb coincident DCD than the to be non- less determined STP (see DEP T1 value hourly coincident 5.0-1). (Yes/No) Discussion Bounded No wet-bulb (non- 4 Site Characteristics -15.8°C (3.6°F) Yes 31.3°C (88.3°F) (88.3°F) 31.3°C coincident) Design Parameters STP 3 & ABWR Standard Plant Site Site Plant ABWR Standard Minimum: (-40°F) -40°C Maximum 27.2°C (81°F) wet-bulb (non-coincident) Table 2.0-2 Comparison of ABWR Standard Plant Site Design Parameters and STP 3 & 4 Site Characteristics (Continued) STP 3 & 4 Site Characteristics and Parameters Site Design Plant of ABWR Standard Comparison 2.0-2 Table Subject
Site Characteristics 2.0-7 Rev. 12
STP 3 & 4 Final Safety Analysis Report ristic wet-bulb (non- on liquefaction potential The UHS cooling tower long-term cumulative cumulative long-term tower UHS cooling The LOCA case for the postulated evaporation the STP site- using evaluated has been day consecutive 30 worst-case specific in FSAR Section as discussed data weather water 9.2.5.5.1. UHS basin The the using evaluated been has temperature STP 3 & 4 site characte 0% exceedance Thus, the value. coincident) non values for 1% exceedance and coincident wet-bulb temperatures not being STP the on impact no adverse have bounded in determined as UHS performance & 4 3 with RG 1.27. accordance bearing capacity is provided in Subsection 2.5S.4. 2.5S.4.4 and in Subsections provided 2.5S.4.7. 2.5S.4.8. in Subsection is provided (Yes/No) Discussion Bounded Yes static minimum on information Further 4 Site Characteristics See Note 6a Note See None No wave velocity shear on information Further Yes information Further Minimum bearing capacity 718.20 kPa 718.20 capacity bearing Minimum (15,000 (grosspsf) pressure)with average settlements up to 7.0 inches Design Parameters STP 3 & um Static Bearing Bearing Static um ABWR Standard Plant Site Site Plant ABWR Standard Minimum Shear Wave Velocity: Velocity: Wave Shear Minimum [6] ft/sec) m/s 305 (1000 Potential: Liquefaction from resulting site at plant None site specific SSE ground motion Capacity: Capacity: [5] psf) kPa (15,000 718.20 Table 2.0-2 Comparison of ABWR Standard Plant Site Design Parameters and STP 3 & 4 Site Characteristics (Continued) STP 3 & 4 Site Characteristics and Parameters Site Design Plant of ABWR Standard Comparison 2.0-2 Table Subject Soil PropertiesSoil Minim
2.0-8 Site Characteristics Rev. 12
STP 3 & 4 Final Safety Analysis Report s consistent with the s consistent ation on the SSE Response of in Subsection PGA 2.5S.2.6. is provided GMRS is provided with site-specific Spectra in Subsection 2.5S.2.6. time historie specific input 2.5S.2 as in Subsection GMRS defined of the site specific analysis seismic to the structures. (Yes/No) Discussion Bounded Yes on the GMRS calculation information Further r RG 1.208 Yes Further inform 4 Site Characteristics GMRS developed pe – – of site- 3H.6 for discussion See Appendix Ground Mean Response Spectra Spectra Response Mean Ground 0.09g (GMRS) PGA: Response ound Acceleration Design Parameters STP 3 & ABWR Standard Plant Site Site Plant ABWR Standard SSE Response Spectra: Spectra: SSE Response RG 1.60 per History: SSE Time Envelope SSE Spectra (PGA): 0.30g [7] Table 2.0-2 Comparison of ABWR Standard Plant Site Design Parameters and STP 3 & 4 Site Characteristics (Continued) STP 3 & 4 Site Characteristics and Parameters Site Design Plant of ABWR Standard Comparison 2.0-2 Table Subject Seismology SSE Peak Gr
Site Characteristics 2.0-9 Rev. 12
STP 3 & 4 Final Safety Analysis Report is -7 and and -7 light Rules as discussed in criteria specified in criteria specified tive assumption since -7 Instrument F Instrument will fly point-to-point per year as discussed in discussed as year per -7 could impact the STP could site was impact conservatively x 10 1.09 estimated at Subsection 2.2S.2.7.2. When estimating the the estimating 2.2S.2.7.2. When Subsection nearest the along of operations number of the number to the STP site (V-70), airway airports-Palacios at of the each operations International Scholes and Airport, Municipal V-70)- airway of points (the terminal Airport for airways the among divided equally were potential the to determine each airport airway. V-70 the along of operations number This is a very conserva fly under mainly aircraft aviation general Flight Rules or Visual Aviation Federal new under and condition most commercial regulations, Administration aircraft and military rather than in specific airways. conservatism inherent of the because Thus, the accident analysis, in the aircraft estimated hazard aircraft of 1.09 x 10 within the order of magnitude 10 of of magnitude order the within meets the intent of the Section NUREG-0800, and 1.206 RG 3.5.1.6. in the STP site vicinity hazards other No a approach could that identified were of 10 frequency Section 2.2S. Section in Subsection 2.2S.3. provided discussed in Subsection 2.5S.1. (Yes/No) Discussion Bounded No that hazards of the aircraft An evaluation per year per -7 4 Site Characteristics Site Proximity: Missiles - None Aircraft hazard 1.09 x 10 NoneNone Yes Yes is gases toxic on information Further activity volcanic information on is Further Design Parameters STP 3 & per year per -7 ABWR Standard Plant Site Site Plant ABWR Standard 10 Site Proximity Missiles and Aircraft: ≤ Toxic Gases: Toxic None Activity: Volcanic None Table 2.0-2 Comparison of ABWR Standard Plant Site Design Parameters and STP 3 & 4 Site Characteristics (Continued) STP 3 & 4 Site Characteristics and Parameters Site Design Plant of ABWR Standard Comparison 2.0-2 Table Subject Hazards in Site Vicinity
2.0-10 Site Characteristics Rev. 12 STP 3 & 4 Final Safety Analysis Report /Q values is provided χ the EAB is provided in ur 0.5% maximum ur 0.5% maximum sector damaging directions. tal windtal speed of the design tomobile, a 125-kg,tomobile, 20-cm a ft/sec). The deviations ft/sec). from the tion and a small resistance, rigid locity(3-second gust) of 203 km/h ity (3-second gust) of 224 km/h per 26.3°C wet bulb (co incident) and outdoor Subsection 2.3S.4. Subsection in Subsection 2.3S.4. is the PAVAN generated 2-hour 0.5% maximum is the PAVAN 3 is the PAVAN generated 2-ho the PAVAN is tes to 1 hour PMP of 0.32 as found in National Weather 3 (Yes/No) Discussion s/m Bounded Yes Further information on YesYes on information Further Yes s/m -4 -5 l impacting at 35% of thel maximum horizon impacting I structures are less than 305 m/s (1,000 on impact, a rigidon missileimpact, to test penetra cture interaction analysis. lue at the EAB; 2.74 x 10 “Determining Design Basis Flooding at Power Reactor Sites.” rmal incidence,to impinge the upon last openingsmost thein 3[11] 3[10] 4 Site Characteristics protective barriers. These missilesof an consists 1800-kg au 3 3[10] 3[11] 3 s/m r safety-related structuresr only; corresponds veloca wind to s/m -4 -5 d by site-specific soil stru gn of non-safety-related structures only; corresponds to a wind ve rm rate: 16.3 cm/5 min per Subsectionrm 2.4S.2.3.1. 2.74E-04s/m 1.62E-04s/m 2.74 x 10 3.99E-05s/m 5.27 x 10 7.09E-07s/m ed based on outdoor summer temperatures of 32.8°C dry bulb and dry of 32.8°C temperatures summer ed based on outdoor high-kinetic energymissile that deforms probable maximum precipitation (PMP) with ratio of 5 minuwithof 5 probableratio (PMP) maximum precipitation nd a 2.54-cm diameter solid steel sphere, al 2 hs below the foundation of seismic Category reactor and control buildings. 3 3 3 s/m s/m -3 -6 -4 our 5.0% overall site va site generated 2-h our 5.0% overall is the PAVAN is the PAVAN generated 2-hour 5.0% overall site value at the LPZ; 5.27 x 10 Design Parameters STP 3 & 3 3 s/m s/m ABWR Standard Plant Site Site Plant ABWR Standard -3 s/m /Q less than or equal x to 1.37 /Q equal than or less -4 -4 -5 An area whose boundary has a has boundary whose An area χ 10 Maximum annual average (8760 (8760 average annual Maximum LPZ: hour) 1.17x10 Maximum 2-hour EAB: 95% 2-hour Maximum s/m 1.37x10-3 Maximum 2-hour LPZ: 95% 2-hour Maximum 4.11x10 minimum shear wave velocity requirement will be justifie winter temperature of 2.1°C dry bulb. winterof 2.1°C dry temperature basis tornado. The first two missiles are assumed to impact at no at Thebasis tornado.to impact first two missiles are assumed subsection 3.3.1.1. subsection sector value at the EAB. value at the sector atvalue the LPZ. wind per Subsection 3.3.1.1. diameter armor piercing artillery shell, a Source PublicationshortHMR No. 52. Maximum te throughanymissile of a sizejust openings to pass sufficient in [7] Free-field, at plant grade elevation. [8] Probable maximum flood level (PMF), as defined in ANSI/ANS-2.8, [9] design systems are HVAC Non-safety-related [10] x 10 1.62 [5] At foundationthelevel of [6]isthe minimum thewave Thisbeenshear have soil property low velocity applied.after uncertainties strains at [6a] Shear wave velocities at multiple dept [3] Maximum value for 1 hour over 2.6 km [11] x 10 3.99 [2] 100-yearrecurrence interval;fo designto be utilized value fo [4] I missiles consist of a massive Spectrum [1] 50-year recurrence interval; value to be utilized for desi Table 2.0-2 Comparison of ABWR Standard Plant Site Design Parameters and STP 3 & 4 Site Characteristics (Continued) STP 3 & 4 Site Characteristics and Parameters Site Design Plant of ABWR Standard Comparison 2.0-2 Table Subject /Q) χ Meteorological Meteorological Dispersion ( Exclusion Area Boundary (EAB)
Site Characteristics 2.0-11 Rev. 12 STP 3 & 4 Final Safety Analysis Report of thealso are COLA dspeedand tornado-generated missiles notedin various sections generatedmissile spectrum 3.5-2).(Refer to STP DEP applicablehurricane towind speedassociated and hurricane- [12]andapplicable Design exceptions requirements to tornado win
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2.0S Site Characteristics This chapter describes the geological, seismological, hydrological, and meteorological characteristics of the STP site and vicinity. The site characteristics are described in conjunction with present and projected population distribution, land use, site activities and controls. The site characteristics were developed in accordance with the relevant requirements of 10 CFR Parts 20, 50, 52, and 100; and are consistent with the guidance provided in Regulatory Guide (RG) 1.206. The site location and description are provided in sufficient detail to support a safety assessment for three types of safety analyses: the exposure of the public to radiation at the boundary of the restricted area of the plant; the consequences of a serious release of radioactive material in the unlikely event that one should occur; and the effect that routine use and accidents on transportation routes near the site would have on the operation of the proposed units. The chapter is divided into five sections:
Geography and demography (Section 2.1S)
Nearby industrial, transportation, and military facilities (Section 2.2S)
Meteorology (Section 2.3S)
Hydrology (Section 2.4S)
Geology and seismology (Section 2.5S)
2.1S Geography and Demography 2.1S.1 Site Location and Description The following site-specific supplemental information addresses COL License Information Item 2.3.
2.1S.1.1 Site Location STP 3 & 4 are located on the existing STP site. The 12,200 acre STP site is located in a rural area of south-central Matagorda County. Figure 2.1S-1 depicts the STP site and the surrounding area within 50 miles. Figure 2.1S-2 depicts the general location of the STP site and localities surrounding the site within 10 miles. Matagorda County lies in the Coastal Prairie region in the southeastern part of Texas, along the Gulf of Mexico. The STP site is located approximately 89 miles southwest of Houston, Texas, and 200 miles southeast of Austin, Texas. The county is bounded on the north by Wharton County, on the east by Brazoria County and the Gulf of Mexico, on the west by Calhoun and Jackson counties, and on the south by the Gulf of Mexico and Tres Palacios, West and East Matagorda Bays. Matagorda County extends across 1612 square miles of mostly open prairie with extensive forests, wetlands and coast. The landscape in the county generally is broad and nearly level. Agriculture, mainly rice farming, and fishing are major industries in Matagorda County. Additionally, the county contains numerous offshore oil rigs and natural gas extraction facilities. The prominent natural features of the region surrounding the STP site, as shown on Figures 2.1S-1 and 2.1S-2, include: the Colorado River, which bisects the county from north to south;
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East and West Matagorda Bays, which are protected by the Matagorda Peninsula; and Tres Palacios Bay and River. The west branch of the Colorado River, as well as several sloughs, flow through the STP site boundary. One of the sloughs feeds 34.4 acre Kelly Lake, which is at the northeast corner of the STP site. The Colorado Barge Canal extends 15 miles along the Colorado River from the Gulf Intracoastal Waterway to a turning basin below Bay City and links the county to deep water at Freeport and Galveston (References 2.1S-1 and 2.1S-2).
As depicted in Figures 2.1S-1 and 2.1S-2, Matagorda County with a 2005 U.S. Census Bureau estimated population of 37,849, includes two incorporated cities: Bay City, the county seat, and Palacios; and four unincorporated towns: Blessing, Markham, Matagorda, and Van Vleck. The STP site is situated 12 miles south-southwest of the city limits of Bay City. Of the cities and towns located in Matagorda County, only the town of Matagorda is located within 10 miles of the STP site. Communities located nearby the STP site include: Collegeport, located approximately 8.5 miles to the southwest; Wadsworth, located approximately 8.5 miles to the northeast; and El Maton located approximately 7.3 miles to the northwest. There are two small developments, Selkirk Island and Exotic Isle, located near the eastern boundary of the site on the Colorado River, approximately 3.5 miles southeast of STP 3 & 4. (References 2.1S-3, 2.1S-4, and 2.1S-5).
There are several recreational and park areas located in Matagorda County. A few of these recreational areas are located near the STP site as depicted in Figure 2.1S-2. Farm-to-Market Road (FM) 521 River Park is a 13-acre park operated by Matagorda County located approximately 4 miles east of the STP site on FM 521. Baycel Golf Club is located approximately 4.8 miles north-northeast of the STP site near OXEA Corporation. And, the Rio Colorado golf course, camping, and recreational area is located north of the OXEA Corporation, just south of Bay City. The Matagorda Bay Nature Park is a 1600-acre nature park and preserve located at the mouth of the Colorado River on the Matagorda Peninsula approximately 11 miles south-southeast of the STP site. The Matagorda County Birding Nature Center spans 34 acres on the Colorado River and is located approximately 12 miles north of the STP site. There are no recreational areas located within the STP site (References 2.1S-6, 2.1S-7, and 2.1S-8).
In addition to the existing units (STP 1 & 2), STP 3 & 4 are located near two petrochemical plants operated, respectively, by OXEA Corporation, formerly Celanese, and Equistar; one wastewater treatment plant, Matagorda Waste Disposal & Water Supply Corporation (in the town of Matagorda); and one public wharf as depicted on Figure 2.1S-2. OXEA is located approximately 4.8 miles north-northeast from the STP site. Equistar is located approximately seven miles east of the STP site. The Port of Bay City (POBC) is a public wharf adjacent to OXEA Corporation located along the Colorado River approximately 4.6 miles north-northeast from STP 3 & 4. Located at the POBC terminal are two petroleum storage facilities; Gulfstream Terminal and Marketing, LLC, and GulfMark Energy, Inc. There are no military installations near the STP site. The closest military base is Ingleside Naval Station located in Ingleside Texas, approximately 90 miles southwest of the STP site (References 2.1S-9, 2.1S-10, and 2.1S-11).
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Matagorda County is traversed by several highways. Texas State Highway 35 runs east/west to Texas State Highway 288, connecting northward to Houston. Texas State Highway 60 runs north/south, joining US Highway 59 in Wharton, proceeding northeast to Houston. Providing main access to the STP site is a rural road, FM 521, which runs along the northern boundary of the STP site. FM 521 provides a connection with both State Highways 60 and 35 (References 2.1S-3 and 2.1S-12).
2.1S.1.2 Site Description With the exception of STP 1 & 2, no commercial, industrial, institutional, recreational, or residential structures are located within the STP site area. STP 3 & 4, a two-unit ABWR, is located to the northwest of the existing units as delineated on the site area maps (Figures 2.1S-3 through 2.1S-4). The center point of Unit 3 reactor building is approximately 1400 feet west and 1500 feet north of the center point of the Unit 2 containment. The Unit 4 footprint is separate from, but adjacent to the Unit 3 footprint. The center point of Unit 4 is approximately 900 feet west of the center point of Unit 3. The combined powerblock footprints of STP 3 & 4 encompass an area of approximately 53 acres. (Figure 2.1S-5) The STP site primarily resides within the Blessing SE, Texas 7 ½ -minute United States Geological Survey (USGS) topographic quadrangle with portions of the STP site lying within the Palacios NE, Texas, the Matagorda, Texas, and the Wadsworth, Texas 7-½ minute quadrangles. The coordinates of the center of the reactor containment building for STP 3 & 4 are given below in the Geodetic Latitude/Longitude and the Universal Transverse Mercator (UTM) coordinate systems:
UTM, Zone 14N UTM, Zone 14N Latitude/Longitude Latitude/Longitude (102 W to 96W) (102W to 96W) Unit (NAD 27) (Degrees) (NAD 83) (Degrees) (NAD 27) (Meters) (NAD 83) (Meters) 3 N 28° 47’ 57” N 28° 47´ 59” North/South North/South 3,189,137.59 3,189,341.26 W 96° 03’ 15” W 96° 03’ 16” East/West East/West 787,547.30 787,517.51 4 N 28° 47’ 58” N 28° 47’ 59” North/South North/South 3,189,137.70 3,189,341.37 W 96° 03’ 25” W 96° 03’ 26” East/West East/West 787,272.78 787,242.99 2.1S.2 Exclusion Area Authority and Control The following site-specific supplemental information addresses COL License Information Item 2.4.
As required by 10 CFR 100.21(a), an Exclusion Area Boundary (EAB) and a low population zone (LPZ) have been identified to meet the requirements established in 10 CFR 100.3. STP 3 & 4 are located within the EAB and the LPZ already designated for STP 1 & 2. The EAB is an oval having a minimum distance of approximately 4692 feet from the center of each of the STP 1 & 2 reactor containment buildings. The center
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of the exclusion area “oval” is a point approximately 305 feet directly west of the center of the Unit 2 Reactor Containment Building depicted on Figure 2.1S-4. This point is also the center of the existing LPZ, which is a circle with a radius of 3 miles. The EAB and LPZ are depicted on Figures 2.1S-3 and 2.1S-4.
2.1S.2.1 Authority The STP participants own the land, including the mineral executive rights, within the site boundary except for the rights of way for the public roads (FM 521, County Road 392 extending south from FM 521 and adjacent to the western boundary of the site, and County Road 360, branching off the northeast corner of FM 521 as it loops around the site for meteorological tower access). The site boundary entirely encompasses the designated EAB for STP 3 & 4. The STP participants have delegated to STPNOC the authority to determine all activities within the EAB, including the exclusion and removal of personnel and property. STPNOC has authority over the EAB in the event of an emergency to afford protection of public health and safety.
2.1S.2.2 Control of Activities Unrelated to Plant Operation No person or entity can reside, build, or conduct other activities within the designated EAB for STP 3 & 4 without STPNOC's approval. The only area that exists within the EAB in which activities unrelated to plant operation can occur is the Visitor Center, which is located inside the Nuclear Training Facility. The Nuclear Training Facility is located inside the Owner Controlled Area and the EAB, but outside of the guard posts. All non-essential individuals in the EAB, including those in the Visitor Center, will be evacuated consistent with emergency planning procedures in the event of an emergency.
2.1S.2.3 Arrangements for Traffic Control No federal, state, or county roads or railways traverse the STP EAB.
2.1S.2.4 Abandonment or Relocation of Roads There are no public roads traversing the STP 3 & 4 exclusion area which, due to their location, have to be abandoned or relocated.
2.1S.3 Population Distribution The following site-specific supplemental information addresses COL License Information Item 2.5.
The population surrounding the STP site, to a 50-mile radius, was estimated based on 2000 decennial census data from the United States Census Bureau (USCB) using SECPOP2000, a code developed for the NRC by Sandia National Laboratories, to calculate population by emergency planning zone sectors (Reference 2.1S-13). The population distribution was estimated in 10 concentric rings at 0-1 mile, 1-2 miles, 2-3 miles, 3-4 miles, 4-5 miles, 5-10 miles, 10-20 miles, 20-30 miles, 30-40 miles, and 40- 50 miles from the STP site, and 16 directional sectors, each sector consisting of 22.5 degrees. The populations for years 2010 through 2080 have been projected by calculating a growth rate using state population projections (by county) as the basis.
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2.1S.3.1 Resident Population Within 10 Miles Figure 2.1S-6 shows the general locations of the municipalities and other features within 10 miles of the STP site. According to the 2000 census (Reference 2.1S-14), Matagorda-Sargent census county division (CCD), which had a population of 3,335 in 2000, is the largest community within 10 miles of the site (Reference 2.1S-14). The small communities of Collegeport, El Maton, and Wadsworth also lie within 10 miles of the site. These very small communities are not explicitly listed in the 2000 census; however, their counts are included in the concentric circle population counts.
The resident population distribution within 10 miles of the site was computed by overlaying the 2000 census block (the smallest unit of census data) on the grid shown on Figure 2.1S-6, and summing the populations of the census block points within each sector. SECPOP uses the 2000 block data from the USCB and overlays it onto the sectors in the annuli prescribed by the user. The population projections to Year 2040 for each county within 50 miles of STP were obtained from the Texas State Data Center and used to calculate an exponential growth rate for each county within the 50- mile radius (Reference 2.1S-16). The growth rate for each county was then used to project future populations (within each sector, taking into account the percent of each sector in a particular county).
The population distributions (including transient population) and related information were tabulated for all distances within each of the 16 sectors. Figures 2.1S-7 through 2.1S-15 show the resident and transient populations for the Year 2000 and the projected populations (by decade) through the Year 2080. The current population within 10 miles can be conservatively assumed to be that shown for the Year 2010. The projected population for the expected first year of plant operation can conservatively be assumed to be that shown for the Year 2020. Each figure also provides totals by direction and by radius. The SECPOP2000 results (with transient population added) produced the 10-mile radius populations for the years 2000 through 2080 (by decade) as follows:
10-Mile Radius Year Population 2000 6,314 2010 6,692 2020 7,135 2030 7,578 2040 8,081 2050 8,587 2060 8,857 2070 9,726 2080 10,357
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2.1S.3.2 Resident Population Between 10 and 50 Miles The 50-mile radius centered at STP includes all or parts of nine counties in Texas (Figure 2.1S-16). Estimates of the Year 2000 resident population between 10 and 50 miles from STP were computed using the same methodology used to develop the 10- mile population distribution.
The population grid from 10 to 50 miles is shown on Figure 2.1S-16. Transient population was not quantitatively determined for the 10 to 50 mile radii because, compared with the resident population, it is expected to be insignificant. The 10 to 50- mile population distributions for the years 2000 through 2080 (by decade) are shown on Figures 2.1S-17 through 2.1S-25. The 50-mile radius populations (including the 0 to 10-mile populations) for each year are as follows:
50-Mile Radius Year Population 2000 258,960 2010 287,750 2020 321,809 2030 360,910 2040 405,752 2050 455,721 2060 514,026 2070 580,967 2080 657,940 2.1S.3.3 Transient Population 2.1S.3.3.1 Transient Population Within 10 Miles The transient population segment includes persons in the workforce, hotels/motels, and recreational areas, as well as seasonal residents and migrant populations. The major employment facilities in the area, in addition to STP, include OXEA Corporation and Equistar Chemicals, LP. OXEA Corporation is located approximately five miles north-northeast of the plant and employs a total of 155 persons. Equistar, located about seven miles east of the STP site, employs 194 workers.
Recreational opportunities in the area include Riverside Park, Baycel Golf Club, Rio Colorado Golf Club, FM 521 River Park, Fisherman's Motel, Lighthouse RV Park, Matagorda Harbor, and the Mad Island Wildlife Management Area (WMA). Accounting for major employers (other than STP), overnight accommodations, major recreation areas, and marinas within the 10-mile radius, a total of 1,622 transients could be present within the 10-mile radius.
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The seasonal population category includes those who reside in the area on a temporary basis. Based on USCB information on seasonal housing, an estimated 1,864 persons reside within the STP 10-mile Emergency Planning Zone on a seasonal basis. Migrant workers are another category of transients that are considered in this analysis. However, according to the Matagorda County Agricultural Extension Agency and the Texas Workforce Commission, there are few, if any migrant workers within 10 miles of the plant due to the mechanized nature of the agricultural industry in this area (Reference 2.1S-17).
The 10-mile transient population was added to the resident distribution and projected for future years (Figures 2.1S-7 through 2.1S-15). The baseline transient population distribution for the 10-mile radius is as follows:
Number of Radius Direction Transients 3-4 E 15 3-4 ESE 28 4-5 NNE 205 4-5 ESE 48 4-5 SE 148 5-10 NNE 416 5-10 ENE 52 5-10 E 198 5-10 ESE 100 5-10 SE 1,624 5-10 SSE 100 5-10 S 40 5-10 SW 44 5-10 WSW 124 5-10 W 20 5-10 WNW 316 5-10 NW 8 TOTAL 3,486
2.1S.3.3.2 Transient Population Between 10 and 50 Miles The Office of the Governor, Economic Development and Tourism (Texas Tourism) lists five counties that fall within the STP 50-mile radius in the Gulf Coast Region of Texas: Matagorda, Brazoria, Wharton, Colorado, and Fort Bend. The number of person-trips to the Gulf Coast for 2003 through 2004 (two-year period) was 33 million (16.5 million person-trips per year), and the volume of person-days was 72 million (36 million
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person-days per year). Leisure travel represented 73% of travel (in person-days) to the Gulf Coast Region, with business travel making up the remaining 27%. The Gulf Coast Region's share of total person-days ranked third among Texas' ten regions, behind the South and Metroplex Regions. The Houston-Baytown-Sugar Land Metropolitan Statistical Area (MSA) (which includes Brazoria and Fort Bend counties) represented 69 million of the total 72 million person-days for the two-year period (Reference 2.1S-18).
The counties of Lavaca, Jackson, Victoria, and Calhoun, portions of which fall within the 50 mile radius, are contained within the South Region, as defined by Texas Tourism. The number of person-trips to the South Region was estimated at 45 million person-trips for the 2003-2004 two-year period (22.5 million person-trips per year) and 99 million person-days (49.5 million person-days per year). Leisure travel represented 76% of travel (in person-days) with business travel making up the remaining 24%. The Victoria MSA, consisting of Victoria County, is the only South Region MSA with a portion within the STP 50-mile radius and had the least number of visitors (2 million person-days for 2003 and 2004) of the South Region MSAs (Reference 2.1S-19).
Seasonal agricultural workers also make up a portion of the transient population in the 10 to 50-mile radius. Farms in the following Texas counties that fall wholly or partially within the 50-mile radius employ migrant labor: Brazoria (20 farms), Calhoun (2), Colorado (29), Fort Bend (3), Jackson (1), Lavaca (11), Matagorda (72), and Wharton (40) (Reference 2.1S-20).
It is difficult to provide an accurate count of the transient population between 10 and 50 miles. Because of this uncertainty, the transient population was not keyed to sectors or projected for future years. However, compared with the resident population within a 50-mile radius, the size of the transient population is expected to be relatively insignificant.
2.1S.3.4 Low Population Zone The Low Population Zone (LPZ) for STP 3 & 4 is the same as the LPZ for STP 1 & 2, and consists of the area within a 3-mile radius of a point 305 feet directly west of the center of the Unit 2 containment (Reference 2.1S-17). Although the center of the LPZ is slightly offset from the center of the direction sectors (Figure 2.1S-6), the population distribution is not affected by this offset. No facilities or institutions requiring special consideration for emergency planning purposes such as schools, nursing homes, hospitals, prisons, or major employers (other than STP) are known to exist within the LPZ or out to a distance of 5 miles. No transient or seasonal populations were identified in the LPZ. Figure 2.1S-26 shows topographical features of the LPZ.
The resident and transient population distributions within the LPZ for each decade from 2000 through 2080 can be seen on Figures 2.1S-7 through 2.1S-15. The total populations within the LPZ for Year 2000 and projected through Year 2080 are as follows:
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LPZ Year Population 2000 16 2010 17 2020 18 2030 19 2040 20 2050 21 2060 23 2070 25 2080 27 2.1S.3.5 Population Center The closest population center (population of greater than 25,000) is considered to be Bay City CCD, which contains Bay City and Van Vleck, and is located approximately 12 miles north-northeast of the STP site. The Bay City CCD had a 2000 population of 24,238, not including transient population (Reference 2.1S-14). Considering transient population and Matagorda County's projected positive growth rate (Reference 2.1S- 16), Bay City CCD's population is assumed to exceed 25,000. The distance to the closest boundary of the population center is more than the radius of the 3-mile LPZ. This distance meets the requirement that the population center distance be at least one and one-third times the distance from the reactor to the outer boundary of the LPZ (10 CFR 100.21(b)).
The few population groupings within the 10-mile radius are unincorporated communities with small populations (Figure 2.1S-6). The overall population density within the 10-mile radius is 20.1 persons per square mile and is projected to increase to 33.0 by the Year 2080. The 5 to 10-mile southeast sector, containing the unincorporated community of Matagorda, is the sector with the highest population density within the 10-mile radius (142.0 for the Year 2000 and 232.9 for the Year 2080). The 4- to 5-mile southeast sector also has a significantly higher population density than the overall area with a Year 2000 density of 140.2 persons per square mile and a projected Year 2080 density of 230.2 persons per square mile.
2.1S.3.6 Population Density Given a conservative reactor startup date of 2020, and an operational period of 60 years, operations could extend until 2080. Figure 2.1S-27 shows the cumulative population in year 2000 within 20 miles of the site and projected cumulative populations in years 2020 and 2080. The population density in year 2015 would be less than that in year 2020. On the same figure, spanning the same radial distances, a population curve is shown for a hypothetical density of 500 persons per square mile as specified in Regulatory Guide 4.7, Position C.4 (Reference 2.1S-21). The 2020 as
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well as the 2080 populations are below the 500 persons per square mile density criteria specified in Regulatory Guide 4.7 at all radial distances.
2.1S.4 References 2.1S-1 “Soil Survey of Matagorda County, Texas,” issued 2001. Available at http://soildatamart.nrcs.usda.gov/Manuscripts/TX321/0/Matagorda.pdf, accessed January 29, 2007.
2.1S-2 “The Handbook of Texas Online,” The University of Texas at Austin, last updated June 6, 2001. Available at http://www.tsha.utexas.edu/handbook/online/articles/MM/hcm5.html, accessed September 28, 2006.
2.1S-3 “Bay City Area Map,” Five Star Maps, Inc., Carbon, Texas, 2006 Edition.
2.1S-4 “U.S. Census Bureau, State & County QuickFacts.” Available at http://quickfacts.census.gov/qfd/states/48/48321.html, accessed September 29, 2006.
2.1S-5 “Matagorda County Community Plan 2006-2007,” December 2006. Available at http://www.co.matagorda.tx.us/ips/export/sites/matagorda/downloads/Co mmunity_Planx_2006-2007.pdf, accessed March 20, 2007.
2.1S-6 “Lower Colorado River Authority website.” Available at http://www.lcra.org/about/parks_preserves.html, accessed January 25, 2007.
2.1S-7 “Matagorda Area Chamber of Commerce Website.” Available at http://www.matagordachamber.com/, accessed January 25, 2007.
2.1S-8 “Baycel Golf Club.” Available at http://www.touringtexas.com/golf/east.htm, accessed April 19, 2007.
2.1S-9 EPA, EnviroMapper Website. Available at http://134.67.99.122/enviro/emef.asp?xl=-96.38485&yt=29.23175&xr=- 94.9209&yb=28.01375, accessed on January 29, 2007.
2.1S-10 “Google Earth, Map of area surrounding STP,” accessed January 29, 2007.
2.1S-11 “Port of Bay City Authority website.” Available at http://www.portofbaycity.com/index.html, accessed March 16, 2007.
2.1S-12 “Matagorda County Economic Development Corporation Website.” Available at http://www.mcedc.net/CommunityProfile.html, accessed January 25, 2007.
2.1S-13 “SECPOP2000: Sector Population, Land Fraction, and Economic Estimation Program, NUREG/CR-6525, Rev. 1,” August, 2003.
2.1S-10 Geography and Demography Rev. 12
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2.1S-14 “Matagorda County, Texas - County Subdivision and Place. GCT-PH1. Population, Housing Units, Area, and Density: 2000,” USCB (U.S. Census Bureau) 2000. Available at http://www.factfinder.census.gov, accessed February 23, 2007.
2.1S-15 “Matagorda County Community Plan 2006-2007,” Matagorda County, December 2006.
2.1S-16 “Projections of the Population of Texas and Counties in Texas by Age, Sex and Race/Ethnicity for 2000-2040,” Texas State Data Center, Office of the State Demographer, Institute for Demographic and Socioeconomic Research, The University of Texas at San Antonio, October, 2006.
2.1S-17 “STPEGS Updated Final Safety Analysis Report, Units 1 and 2” Revision 13.
2.1S-18 “Texas Destinations, 2003-2004 - Gulf Coast Region.,” D. K. Shifflet and Associates 2005. Prepared for Texas Economic Development and Tourism.
2.1S-19 “Texas Destinations, 2003-2004 - South Region,” D.K. Shifflet and Associates 2005. Prepared for Texas Economic Development and Tourism.
2.1S-20 “Texas State and County Data, 2002 Census of Agriculture, Volume 1, Geographic Area Series, Part 43A, AC-02-A-43A,” National Agricultural Statistics Service, USDA (U.S. Department of Agriculture), June 2004.
2.1S-21 “General Site Suitability Criteria for Nuclear Power Plants,” Regulatory Guide 4.7, Revision 2, April 1998.
Geography and Demography 2.1S-11 Rev. 12
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Figure 2.1S-1 Surrounding Area Map Figure 2.1S-1
2.1S-12 Geography and Demography Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.1S-2 10-Mile Radius Map 10-Mile Radius Figure 2.1S-2
Geography and Demography 2.1S-13 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.1S-3 Site Area Map Area Site 2.1S-3 Figure
2.1S-14 Geography and Demography Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.1S-4 Enlarged Site Area Map Area Enlarged Site Figure 2.1S-4
Geography and Demography 2.1S-15 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.1S-5 Principal Plant Structures within the STP Site Area Plant Structures within Principal Figure 2.1S-5
2.1S-16 Geography and Demography Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.1S-6 10-Mile Vicinity with Direction Sectors Direction with 10-Mile Vicinity 2.1S-6 Figure
Geography and Demography 2.1S-17 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.1S-7 10-Miles 2000 Population Distribution Population 2000 10-Miles Figure 2.1S-7
2.1S-18 Geography and Demography Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.1S-8 10-Mile 2010 Population Distribution 2010 Population 2.1S-8 10-Mile Figure
Geography and Demography 2.1S-19 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.1S-9 10-Mile 2020 Population Distribution 2020 Population 2.1S-9 10-Mile Figure
2.1S-20 Geography and Demography Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.1S-10 10-Mile 2030 Population Distribution Distribution Population 2030 10-Mile Figure 2.1S-10
Geography and Demography 2.1S-21 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.1S-11 10-Mile 2040 Population Distribution Population 2040 10-Mile Figure 2.1S-11
2.1S-22 Geography and Demography Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.1S-12 10-Mile 2050 Population Distribution Distribution Population 2050 10-Mile Figure 2.1S-12
Geography and Demography 2.1S-23 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.1S-13 10-Mile 2060 Population Distribution Population 2060 10-Mile Figure 2.1S-13
2.1S-24 Geography and Demography Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.1S-14 10-Mile 2070 Population Distribution Population 2070 10-Mile Figure 2.1S-14
Geography and Demography 2.1S-25 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.1S-15 10-Mile 2080 Population Distribution Population 2080 10-Mile Figure 2.1S-15
2.1S-26 Geography and Demography Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.1S-16 50-Mile Region with Direction Sectors Region with Direction 50-Mile Figure 2.1S-16
Geography and Demography 2.1S-27 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.1S-17 10- to 50-Mile 2000 Population Distribution Population 50-Mile 2000 10- to Figure 2.1S-17
2.1S-28 Geography and Demography Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.1S-18 10- to 50-Mile 2010 Population Distribution Population 50-Mile 2010 10- to Figure 2.1S-18
Geography and Demography 2.1S-29 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.1S-19 10- to 50-Mile 2020 Population Distribution Population 50-Mile 2020 10- to Figure 2.1S-19
2.1S-30 Geography and Demography Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.1S-20 10- to 50-Mile 2030 Population Distribution Population 50-Mile 2030 10- to Figure 2.1S-20
Geography and Demography 2.1S-31 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.1S-21 10- to 50-Mile 2040 Population Distribution Population 50-Mile 2040 10- to Figure 2.1S-21
2.1S-32 Geography and Demography Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.1S-22 10- to 50-Mile 2050 Population Distribution Population 50-Mile 2050 10- to Figure 2.1S-22
Geography and Demography 2.1S-33 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.1S-23 10- to 50-Mile 2060 Population Distribution Population 50-Mile 2060 10- to Figure 2.1S-23
2.1S-34 Geography and Demography Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.1S-24 10- to 50-Mile 2070 Population Distribution Population 50-Mile 2070 10- to Figure 2.1S-24
Geography and Demography 2.1S-35 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.1S-25 10- to 50-Mile 2080 Population Distribution Population 50-Mile 2080 10- to Figure 2.1S-25
2.1S-36 Geography and Demography Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.1S-26 Low Population Zone Low Population Figure 2.1S-26
Geography and Demography 2.1S-37 Rev. 12
STP 3 & 4 Final Safety Analysis Report ctual 2000 500/sq. mile 500/sq. 2080 Projected 2020 Projected A Distance from STP (Miles) STP from Distance Figure 2.1S-27 Population Compared to NRC Siting Criteria NRC Siting Compared to Population 2.1S-27 Figure 0 5 10 15 20 0
600,000 500,000 400,000 300,000 200,000 100,000 Cumulative Population Cumulative
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2.2 Requirements for Determination of ABWR Site Acceptability The information in this section of the reference ABWR DCD, including all subsections and tables, is incorporated by reference with the following departures.
STD DEP 2.2-5
STP DEP T1 5.0-1
2.2.1 Design Basis Events STP DEP T1 5.0-1
For design basis events, the site is acceptable if all of the site characteristics fall within the envelope of ABWR Standard Plant site design parameters given in Table 2.0-1. For cases where a characteristic exceeds its envelope, it will be necessary for the COL applicant to submit analyses to a discussion is provided in Table 2.0-2, Subsection 2.4S.10, and Sections 2.2S, 2.5S, 3H.6, 3.4, and 3.8 demonstrate demonstrating that the overall set of site characteristics do not exceed the capability of the design.
2.2.2 Severe Accidents STD DEP 2.2-5
A site-specific accident consequence analysis has been performed for the STP site using the MACCS2 code (NUREG/CR-6613). This analysis demonstrates that the acceptance criteria have been met for the site, and the reference ABWR DCD CRAC2 results are bounding. The site-specific consequence analysis is documented in App 19E.3.
Acceptance Criteria: Site acceptability for severe accidents will be is based upon a calculation using the CRAC 2MACCS2 computer code. The results of such a calculation will beare compared to the goals of Table 19E.3-7 as shown in Table 2.2- 1. The site will beis deemed acceptable if the results fall within the given goals.
Data Input: The input to the CRAC 2MACCS2 computer code will beis a combination of ABWR and site parameters. The CRAC 2MACCS2 code input is divided into specific areas. The areas defined in Table 2.2-2 as ABWR will beare used as input with their specific data listed in Appendix 2A. The areas defined as GENERAL are also provided in Appendix 2A. The areas defined as UTILITY are to bewere supplied by the licensing utilitySTPNOC as specified in the CRAC 2MACCS2 manual (NUREG/CR-23266613) and are site specific. The input data are specified in App 19E.3.2 and the results are presented in App 19E.3.3.2.
Analysis: The analysis for evaluation of a specific site will beSTP 3 & 4 is accomplished with the CRAC 2MACCS2 computer code as modified through Sandia National Laboratory Version 1.13.1 (January 2004)Modification 46. Basic input and code characteristics are described in NUREG/CR-2326 and NUREG/CR- 2552NUREG/CR-6613.
Requirements for Determination of ABWR Site Acceptability 2.2-1/2
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2.2S Nearby Industrial, Transportation, and Military Facilities The purpose of this section is to establish whether the effects of potential accidents on site or in the vicinity of the site from present and projected industrial, transportation, and military installations and operations should be used as design basis events for plant design parameters related to the selected accidents. To meet the guidance in Regulatory Guide (RG) 1.206, all facilities and activities within five miles of STP 3 & 4 were considered. Facilities and activities at greater distances were included as appropriate to their significance.
2.2S.1 Locations and Routes The following site-specific supplement addresses COL License Information Item 2.6.
Potential hazard facilities and routes within the vicinity (five miles) of STP 3 & 4, and airports within 10 miles of STP 3 & 4 were identified along with significant facilities at a greater distance in accordance with RG 1.206, RG 1.91, RG 4.7, and relevant sections of 10 CFR Parts 50 and 100.
An investigation of the potential external hazard facilities and operations revealed that within five miles of STP 3 & 4, there are three significant industrial facilities, five natural gas transmission pipelines, five chemical pipelines, four natural gas gathering pipelines, and five active natural gas and/or oil fields with active extraction wells identified for further analysis. An evaluation of major transportation routes within the vicinity of STP 3 & 4 identified four roads, two airways, and one navigable waterway for assessment (References 2.2S-1 through 2.2S-26 and Reference 2.2S-62).
Potential hazard analysis of internal events includes STP 1 & 2 and onsite chemical and chemical storage facilities.
A site vicinity map (Figure 2.2S-1) details the following identified facilities and road and waterway transportation routes:
Significant Industrial Facilities within Five Miles
OXEA Corporation (formerly Celanese)
Port of Bay City Operations
– Gulfstream Terminal and Marketing
– GulfMark Energy
STP 1 & 2
Transportation Routes within Five Miles
Farm-to-Market (FM) 521 Road
FM 1095
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FM 1468
FM 3057
Colorado River
Figure 2.2S-2 illustrates the following identified natural gas and chemical pipelines, and active natural gas and/or oil extraction fields located within five miles of STP 3 & 4:
Natural Gas Transmission Pipelines
Dow Pipeline Company
Houston Pipeline Company, L.P.
Penn Virginia Oil & Gas, L.P.
Texas Eastern Transmission, L.P.
Enterprise Products Operating, L.P.
Chemical Pipelines
Seadrift Pipeline Corporation (ethylene gas)
OXEA Corporation (propylene)
OXEA Corporation (oxygen)
OXEA Corporation (nitrogen)
OXEA Corporation (ethylene)
Natural Gas Gathering Pipelines
Acock/Anaqua Operating Co., L.P.
Houston Pipeline Company, L.P.
Kinder Morgan Tejas Pipeline, L.P.
Santos USA Corporation
Natural Gas/Oil Extraction Fields
Duncan Slough
Cane Island
Petrucha
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Grand Slam
Wadsworth
An evaluation of nearby facilities and transportation routes within 10 miles of STP 3 & 4 revealed there are two industrial facilities that were significant enough to be identified as potential hazard facilities: Equistar Industries, located approximately seven miles east of STP 3 & 4, and Matagorda Waste Disposal and Water Supply Corporation, located approximately nine miles southeast of STP 3 & 4 (References 2.2S-27 through 2.2S-30). There were two airways identified that operate within 5 to 10 miles of the plant (Reference 2.2S-31). There were no identified hazard facilities, routes, or activities greater than 5 to 10 miles that were significant enough to be identified. The closest military base is Ingleside Naval Station located in Ingleside Texas, approximately 90 miles southwest of the STP site.
Figure 2.2S-1 illustrates the following identified Industrial Facilities within 10 miles of STP 3 & 4, including:
Significant Industrial Facilities within 5 to 10 Miles
Equistar Industries
Matagorda Waste Disposal and Water Supply Corporation
Figure 2.2S-3 illustrates the following identified airports and airway routes within 10 miles of STP 3 & 4, including:
Airport and Airway Routes within 10 Miles
STP Corporate Helipad
Airway V-70
Airway V-20
Items illustrated in Figures 2.2S-1, 2.2S-2, and 2.2S-3 are described in Subsection 2.2S.2.
2.2S.2 Descriptions The following site-specific supplement addresses COL License Information Item 2.6.
2.2S.2.1 Description of Facilities In accordance with RG 1.206, six facilities were identified for review:
STP 1 & 2
OXEA Corporation
The Port of Bay City
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– Gulfstream Terminal and Marketing LLC
– GulfMark Energy
Equistar
Matagorda Waste Disposal and Water Supply Corporation
Table 2.2S-1 provides a concise description of each facility, including its primary function and major products, as well as the number of persons employed.
2.2S.2.2 Description of Products and Materials A more detailed description of each of these facilities, including a description of the products and materials regularly manufactured, stored, used, or transported, is provided in the following subsections. As provided in RG 1.78, chemicals stored or situated at distances greater than five miles from the plant do not need to be considered unless they have been determined to have a significant impact on the proposed facilities. No other facilities or storage locations have been identified that could have a significant impact on the STP site. Therefore, further analysis beyond these six facilities is not required.
2.2S.2.2.1 STP 1 & 2 STP 1 & 2 are located approximately 1500 feet southeast of STP 3 & 4. STP 1 & 2 are each 1329 MWe Westinghouse Electric Company, LLC pressurized water reactors (PWRs) licensed by the NRC. STP 1 & 2 have been in commercial operation since 1988 and 1989, respectively. The chemicals identified for possible analysis and their locations at the STP 1 & 2 site are presented in Table 2.2S-2. There are approximately 1300 people currently employed at STP 1 & 2.
2.2S.2.2.2 OXEA Corporation The OXEA Corporation, formerly Celanese, is a chemical manufacturing facility located approximately 4.3 miles north-northeast of STP 3 & 4. In December of 2006, Advent International purchased selected businesses of Celanese Chemicals and European Oxo, a joint venture of Celanese and Degussa. The companies were consolidated into a new company, OXEA. (The shipping operations and a small portion of the plant that manufactures vinyl acetate remain under the operation of Celanese.) A variety of chemical products are produced at the site, including organic chemicals (basic and industrial), cyclic organic crudes, organic dyes, and pigments. OXEA Corporation employs approximately 260 individuals at the Bay City site; OXEA Corporation has 130 permanent employees; Celanese has 30 permanent employees; and there are approximately 100 contractors on site. No further expansion of this site is planned. Table 2.2S-3 summarizes the quantity of hazardous materials currently stored at the plant and the applicable toxicity limits.
OXEA Corporation receives and ships materials by rail, truck, barge, and pipeline. The facility ships tank rail cars on the Union Pacific rail line spur that travels from Bay City to Blessing. Tank rail cars are also shipped on the Burlington Northern Santa Fe rail
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line that runs east from the plant main line and then to Bay City. The tank trucks are shipped and received via FM 3057 and FM 2668. Neither the truck nor the rail transport routes approach closer to STP 3 & 4 than the storage location of the chemicals at OXEA. OXEA Corporation also ships materials in barges along the Colorado River. Approximately 360 barges per year are shipped on the Colorado River. There are four pipelines that carry products into the plant. More detailed information about these pipelines is presented in Subsection 2.2S.2.3.2 (References 2.2S-1 and 2.2S-2).
2.2S.2.2.3 Port of Bay City The Port of Bay City is a port facility located adjacent to OXEA Corporation along the Colorado River, approximately 4.6 miles north-northeast of STP 3 & 4. The port facility consists of approximately 300 acres of land available for industrial development, a terminal in a turning basin with a modern concrete dock, a metal shed located on the dock, and a liquid cargo dock. Located at the Port of Bay City are two facilities- Gulfstream Terminal and Marketing, LLC, and GulfMark Energy, Inc. A description of each company is provided in Subsections 2.2S.2.2.3.1 and 2.2S.2.2.3.2 (Reference 2.2S-3).
2.2S.2.2.3.1 Gulfstream Terminal and Marketing LLC Gulfstream Terminal and Marketing, LLC (Gulfstream) operates at the Port of Bay City public wharf located 4.6 miles north-northeast of STP 3 & 4. This terminal has been in operation since 1968 under various owners. Gulfstream was formerly owned by Way Energy from 1984 to 2000. Gulfstream receives barge shipments of refined petroleum products such as gasoline and diesel fuel and stores the products until they are delivered by truck to retail terminals. Gulfstream has seven storage tanks located at its facility. There are six tanks with a capacity of 15,000 barrels each, and a seventh tank with a capacity of 20,000 barrels, bringing the total tank capacity at the facility to approximately 110,000 barrels or 4.62 million gallons. The average inventory at the facility at any given time is not expected to exceed 90% of the total capacity. Gulfstream receives an average of six deliveries a month of refined petroleum products by barge. These receipts average approximately 40,000 barrels or 1.68 million gallons. Table 2.2S-3 summarizes the maximum quantity of potentially hazardous materials stored at the terminal and the applicable toxicity limits. Gulfstream currently employs four workers with potential for a slightly increased workforce.
2.2S.2.2.3.2 GulfMark Energy GulfMark Energy is also located 4.6 miles north-northeast of STP 3 & 4 at the Port of Bay City. This terminal is used for receipt, storage, and transfer of petroleum crude oil and condensate. After unloading and storage, the product is delivered to retail terminals via truck. A 12-inch pipeline extends from the wharf to one 25,000 barrel (1.05 million gallons) storage tank. Gulfmark Energy receives one or two barge shipments each month. Each shipment consists of approximately 15,000 to 20,000 barrels (630,000 to 840,000 gallons) of petroleum crude oil. The facility has an average monthly inventory of 12,500 barrels. The oil is offloaded in 180-barrel (7560 gallon) truckloads. Table 2.2S-3 summarizes the maximum quantity of potentially
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hazardous materials stored at the terminal and the applicable toxicity limits. GulfMark Energy does not employ any permanent workers. However, a worker is present in the morning to check gauges and truck drivers arrive and depart after loading or unloading crude oil (Reference 2.2S-4).
2.2S.2.2.4 Equistar Equistar Chemicals (Equistar), a subsidiary of Lyondell Chemical Company, is located seven miles east of STP 3 & 4. Equistar encompasses about 2500 acres and employs 194 people, including subcontractors. No further plant expansion is planned. Equistar produces high-density polyethylene (HDPE) plastic resins. These resins serve as building blocks for a variety of industrial and consumer products such as specialized food packaging and grocery and merchandise bags. This facility receives and ships material by both rail and truck. Truck transport is via State Highway 60 due to the bridge limitations on FM 521 (Reference 2.2S-27). As provided in RG 1.78, chemicals stored or situated at distances greater than five miles from the plant do not need to be considered in the evaluation of control room habitability.
2.2S.2.2.5 Matagorda Waste Disposal and Water Supply Corporation Matagorda Waste Disposal and Water Supply Corporation (Matagorda WD & WSC) is located approximately nine miles southeast of STP 3 & 4 (References 2.2S-28 through 2.2S-30). Matagorda WD & WSC currently employs three workers at the facility. This small waste disposal and water supply corporation provides services to approximately 300 homes and small businesses. Matagorda WD & WSC receives chemicals for water and wastewater treatment by truck. Truck transport is via State Highway 60. As provided in RG 1.78, chemicals stored or situated at distances greater than five miles from the plant do not need to be considered (References 2.2S-28 through 2.2S-30).
2.2S.2.3 Description of Pipelines and Natural Gas/Oil Fields There are five natural gas transmission pipelines, five chemical pipelines, four natural gas gathering pipelines, and five active natural gas and/or oil fields with active extraction wells within five miles of the plant as depicted in Figure 2.2S-2. A more detailed description of each of the pipelines is presented in the following subsections, including the pipe size, age, operating pressure, depth of burial, location and type of isolation valves, and type of gas or liquid presently carried where available. Information pertaining to the various pipelines is also presented in Table 2.2S-4.
As presented in the following subsections, the natural gas transmission pipeline operated by Dow Pipeline Company presents a greater hazard than the gas wells and oil fields due to the safety controls and features on the wells, and the expected damage radius. Careful control and monitoring of drilling operations minimizes the likelihood of a blowout of a gas well. Blowout preventers are also used to reduce the likelihood and consequences of a blowout. Further, damage from the initial effects of a blowout is usually limited to the immediate vicinity of the well. Another accident in producing wells may occur because of failure of the well head equipment and piping as a result of aging, improper operation or damage by vehicles or construction equipment. Of these, the most serious would be the severance of the well head piping such as to cause
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uncontrolled gas release from the well and also a backflow from the gathering line connecting the well to the transmission line. Well head equipment includes flow control valves, shutoff valves, and check valves which would limit flow from the well and/or from the gas transmission line normally supplied by the well.
2.2S.2.3.1 Natural Gas Transmission Pipelines
2.2S.2.3.1.1 Dow Pipeline Company The transmission pipelines nearest STP 3 & 4 are a 16-inch and a 12.75-inch natural gas transmission pipeline operated by Dow Chemical Company. At the closest approach to STP 3 & 4, these pipelines pass within approximately two miles to the northwest of STP 3 & 4 as depicted in Figure 2.2S-2. The easternmost pipeline, Dow Collegeport, was installed in 1940 and is a 12.75-inch diameter pipeline with an operating pressure of 471 psig. The second pipeline, Dow Powderhorn, was installed in 1954 and is a 16-inch diameter pipeline with an operating pressure of 760 psig. Both pipelines are buried at a depth of 3 to 10 feet. It is not expected that Dow Pipeline Company will carry another product in these pipelines (Reference 2.2S-11).
2.2S.2.3.1.2 Houston Pipeline Company, L.P. The Houston Pipeline Company, L.P. operates a natural gas transmission pipeline that passes within approximately 2.8 miles north of STP 3 & 4 as depicted in Figure 2.2S- 2. The pipeline, Matagorda-Brazoria, was installed in 1964 and is an 8.63-inch diameter pipeline with an operating pressure of 575 psig. The pipeline is buried at a depth of two to three feet with a distance of seven to eight miles between isolation valves. Houston Pipeline Company has no plans for carrying a different product in their pipeline. Dow Pipeline Company's pipeline presents a greater hazard than the Houston Pipeline Company's pipeline due to its proximity to STP 3 & 4, and as such, no further analysis of this pipeline is warranted (Reference 2.2S-12).
2.2S.2.3.1.3 Penn Virginia Oil & Gas, L.P. The Penn Virginia Oil & Gas, L.P. operates a natural gas transmission pipeline that passes within approximately 3.8 miles northeast of STP 3 & 4 as depicted in Figure 2.2S-2. The pipeline has a diameter of 4.5 inches. It is not expected that a different product will be carried in the pipeline. Dow Pipeline Company's pipeline presents a greater hazard than the Penn Virginia Oil & Gas, L.P. due to its proximity to STP 3 & 4, and as such, no further analysis of this pipeline is warranted (Reference 2.2S-14).
2.2S.2.3.1.4 Texas Eastern Transmission, L.P. Texas Eastern Transmission, L.P. operates a 30-inch natural gas transmission pipeline that passes within approximately 4.2 miles north of STP 3 & 4 as depicted in Figure 2.2S-2. It is not expected that Texas Eastern will carry a different product in their pipeline. Dow Pipeline Company's pipeline presents a greater hazard than Texas Eastern Transmission, L.P. due to its close proximity to STP 3 & 4, and as such, no further analysis of this pipeline is warranted (Reference 2.2S-10).
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2.2S.2.3.1.5 Enterprise Products Operating, L.P. Enterprise Products Operating, L.P. operates an 8.63-inch natural gas transmission pipeline that passes within approximately 4.2 miles north of STP 3 & 4 as depicted in Figure 2.2S-2. The pipeline was installed in 1969 and has an operating pressure of 750 psig. The pipeline is buried at an average depth of 37 inches. Enterprise Products Operating does not have plans to carry a different product in their pipeline. Dow Pipeline Company's pipeline presents a greater hazard than Enterprise Products Operating, L.P. due to its proximity to STP 3 & 4, and as such, no further analysis of this pipeline is warranted (Reference 2.2S-13).
2.2S.2.3.2 Chemical Pipelines
2.2S.2.3.2.1 Seadrift Pipeline Corporation The Seadrift Pipeline Company operates a nitrogen pipeline 3.5 miles north of STP 3 & 4 as depicted in Figure 2.2S-2. The pipeline was installed in 1962 with a diameter of 4.5 inches and is buried at a depth of 3 to 10 feet. The pipeline operates with a pressure of 1494 psig. It is not expected that a different product will be carried in the pipeline (Reference 2.2S-15).
2.2S.2.3.2.2 OXEA Corporation Propylene Pipeline The OXEA Corporation owns a 6.63-inch propylene line that delivers product into the OXEA plant and passes within approximately 4.3 miles north-northeast of STP 3 & 4. The propylene pipeline was built in 1977 and has an operating pressure of 875 psig. The pipeline is buried at a depth of 38 to 40 inches except at road crossings, where it is five feet below the road crest. The isolation valves are at various distances along the pipeline. OXEA Corporation has no plans to carry a different product in the future in the pipeline (Reference 2.2S-16).
2.2S.2.3.2.3 OXEA Corporation Oxygen Pipeline Air Liquide operates a 12.75-inch oxygen pipeline to the OXEA plant that passes within approximately 4.3 miles north-northeast of STP 3 & 4. The oxygen pipeline is buried at a depth of 38 to 40 inches. This pipeline has an operating pressure of 875 psig. It is not expected that a different product will be carried in the pipeline (Reference 2.2S- 17).
2.2S.2.3.2.4 OXEA Corporation Nitrogen Pipeline Air Liquide operates a 10.75-inch nitrogen pipeline to the OXEA plant and passes within approximately 4.3 miles north-northeast of STP 3 & 4. The nitrogen pipeline is buried at a depth of 38 to 40 inches and has an operating pressure of 875 psig. There are no plans to carry a different product in the pipeline in the future (Reference 2.2S- 17).
2.2S.2.3.2.5 OXEA Corporation Ethylene Pipeline Equistar operates a 10.75-inch ethylene pipeline to the OXEA plant and passes within approximately 4.3 miles north-northeast of STP 3 & 4. The ethylene pipeline was
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installed in 1982 and has a normal operating pressure of 1000 to 1300 psig. The ethylene pipeline is buried at a depth of four to six feet. It is not expected that a different product will be carried in the pipeline (Reference 2.2S-18).
2.2S.2.3.3 Gas Gathering Pipelines
2.2S.2.3.3.1 Acock/Anaqua Operating Co., L.P. Acock/Anaqua Operating Co., L.P. operates a 4.5-inch natural gas gathering line that serves the South Duncan Slough field as depicted in Figure 2.2S-2. This gathering pipeline terminates 1.3 miles northwest of STP 3 & 4. Potential hazards from this line are bounded by the natural gas transmission pipelines due to the larger volume of natural gas in the transmission pipelines (Reference 2.2S-19).
2.2S.2.3.3.2 Houston Pipeline Company, L.P. The Houston Pipeline Company, L.P. operates a 4.5-inch natural gas gathering line that passes within approximately 3.3 miles north of STP 3 & 4. This gas gathering pipeline serves the Duncan Slough field. Potential hazards from this line are bounded by the natural gas transmission pipelines due to the larger volume of natural gas in the transmission pipelines (Reference 2.2S-20).
2.2S.2.3.3.3 Kinder Morgan Tejas Pipeline, L.P. The Kinder Morgan Tejas Pipeline Company, L.P. operates a 16-inch natural gas gathering pipeline that passes within approximately 4.4 miles northwest of STP 3 & 4. Potential hazards from this line are bounded by the natural gas transmission pipelines due to the larger volume of natural gas in the transmission pipelines (Reference 2.2S- 21).
2.2S.2.3.3.4 Santos USA, Corporation The Santos USA, Corporation operates a 4.5-inch natural gas gathering pipeline that passes within approximately three miles north-northwest of STP 3 & 4. Potential hazards from this line are bounded by the natural gas transmission pipelines due to the larger volume of natural gas in the transmission pipelines (Reference 2.2S-62).
2.2S.2.4 Description of Waterways STP 3 & 4 is located approximately 3.2 miles from the west bank of the Colorado River, a navigable waterway. From the Gulf Intracoastal Waterway, the river winds along a 15.6-mile stretch until it approaches the turning basin located at the Port of Bay City facility, approximately 4.6 miles north-northeast of STP 3 & 4. The Port of Bay City is the only dock/anchorage located within 5 miles of the STP site. The stretch of the Colorado River Channel leading to the port facility is approximately 200 feet in width with an average depth of 12 feet. The turning basin is approximately 700 feet in length by 500 feet in width with an average depth of 12 feet (Reference 2.2S-3).
The Colorado River is used primarily for barge traffic. During the 12-month period from January 2005 through December 2005, there were a total of 208 barge and 314 tanker
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upbound trips; and 211 barge and 322 tanker outbound trips recorded. These vessels primarily used the river for the transportation of raw and finished materials to local industrial facilities-predominantly OXEA Corporation and the Port of Bay City terminals. These vessels transported a total of 501,000 tons of commodities in the vicinity of STP 3 & 4. These commodities included 56,000 tons of crude petroleum, 1000 tons of residual fuel oil, 127,000 tons of alcohols, and 317,000 tons of carboxylic acids. Table 2.2S-5 details the total quantity of hazardous materials transported on the Colorado River in the vicinity of STP 3 & 4 (Reference 2.2S-9).
The Colorado River provides makeup water to the main cooling reservoir (MCR). The makeup water system, located at the Colorado River, includes a shoreline pump intake, two buried 108-inch diameter makeup water pipelines, and a discharge outfall at the MCR. The system consists of a traveling screen intake structure, siltation basin, a sharp-crested weir, and a 1200 cfs (cubic feet per second) capacity pump station. The screen intake structure consists of coarse trash racks, stop log guides, and multiple sets of traveling water screens.
The intake structure located on the Colorado River is nonsafety-related. The Ultimate Heat Sink (UHS) provides cooling water to the safety-related plant components. Secondary plant cooling water is provided from the main cooling water reservoir (MCR). Only the MCR receives makeup water directly from the Colorado River; therefore, the makeup intake structure is nonsafety-related, and as such, no further analysis is warranted.
2.2S.2.5 Description of Highways Matagorda County is traversed by several highways. There are four Farm-to-Market roads (FM) within five miles of STP 3 & 4 as depicted in Figure 2.2S-1. FM 521 is the road with the closest approach to STP 3 & 4. At its closest point, FM 521 is approximately 0.4 miles from STP 3 & 4. FM 521 runs in an east-west direction parallel to the STP site northern fence. To the north of the STP site, FM 1468 runs in a north-south direction and intersects FM 521 approximately one mile from STP 3 & 4. FM 521 intersects FM 1095, which also runs in a north-south direction and is located approximately 4.2 miles to the west of STP 3 & 4. Another road located in the vicinity of STP 3 & 4 is FM 3057. FM 3057 runs in an east-west direction and is located north- northeast of the STP 3 & 4. FM 3057 links OXEA Corporation with FM 2668 (Reference 2.2S-8).
To ascertain which hazardous materials may be transported on the roadways within five miles of STP 3 & 4, the industries discussed in Subsection 2.2S.2.2 were contacted to obtain transportation routes. Of the industries contacted, only the chemicals stored at STP are transported within five miles of STP 3 & 4. Each of the on-site chemicals that had the potential to explode, or form a flammable or toxic vapor cloud, were analyzed to determine safe distances. At the closest approach to the nearest safety related structure, FM 521 is 1955 feet. And, the closest approach to the nearest control room is 2853 feet. In each case the on-site chemical was stored in closer proximity to either the identified safety related structure or the Control Room than the closest approach of FM 521. It was determined that, other than the delivery of chemicals to the STP site, a gasoline tanker may possibly use FM 521.
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2.2S.2.6 Description of Railroads There are no railroads in the vicinity (five miles) of STP 3 & 4.
2.2S.2.7 Description of Airports Only one helipad, the STP helipad, is located within the vicinity (five miles) of STP 3 & 4. There are no airports located within five miles of the STP site. Additionally, there are no airports within 10 miles of the site with projected operations greater than 500 d2 operations annually or beyond 10 miles with projected operations greater than 1,000 d2 movements per year, where “d” is the distance in statute miles from the site. The closest municipal airport is Palacios Municipal Airport, with 3000 operations per year. Although small, private airstrips may be present in this area, the flights are sporadic and do not pose a threat to the STP site. Because of the distance and the very low number of projected operations per year, no further evaluation of probability of an aircraft crash associated with nearby airports is warranted (References 2.2S-33 through 2.2S-35).
2.2S.2.7.1 Airports
2.2S.2.7.1.1 STP Helipad The STP site operates its own corporate helipad. The helipad is located east of STP 3 & 4 and is a 30-foot by 30-foot concrete pad. Generally, this helipad is used for executive personnel transport. An average of two to three corporate flights per year make use of the helipad. Helicopters using the helipad are generally single main rotor helicopters. Life Flight out of Houston has landed their largest helicopter at this helipad during an exercise-its gross weight was 7718 pounds. There have been no accidents associated with the helipad. No further analysis of this helipad is warranted (References 2.2S-5 through 2.2S-7).
2.2S.2.7.2 Aircraft and Airway Hazards RG 1.206 and NUREG-0800 state that the risks due to aircraft hazards should be sufficiently low. Further, aircraft accidents that could lead to radiological consequences in excess of the exposure guidelines of 10 CFR 50.34(a)(1) with a probability of occurrence greater than an order of magnitude of 10-7 per year should be considered in the design of the plant. Section 3.5.1.6 of NUREG-0800 provides three acceptance criteria for the probability of aircraft accidents to be less than 10-7 per year: (1) meeting plant-to-airport distance and projected annual operations criteria, (2) plant is at least five miles from military training routes, and, (3) plant is at least two statute miles beyond the nearest edge of a federal airway. The STP 3 & 4 site fails to meet Item 3 of the acceptance criteria.
The centerline of Airway V-70 is approximately 3.5 miles northwest of the site, and the centerline of Airway V-20 is approximately 9.6 miles northwest of the STP site, as depicted in Figure 2.2S-3 (Reference 2.2S-31). The width of a federal airway is eight nautical miles- four miles on each side of the centerline-placing the V-70 airway closer to the plant than two miles to the nearest edge. Because of the proximity to STP 3 &
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4, the criteria set in Section 3.5.1.6 of NUREG-0800-plant is at least two statute miles beyond the nearest edge of a federal airway (V-70)-is not met.
Therefore, a calculation to determine the probability of aircraft accidents that could possibly result in radiological consequences for the STP site was conducted following Department of Energy (DOE) Standard DOE-STD-3014-96. The analysis provided an estimate of the total impact frequency of aircraft per year into the facility-1.09 x 10-7. This meets the NUREG 0800 criteria of about 10-7. When estimating the number of operations along V-70, the number of operations at each of the airports-Palacios Municipal Airport, and Scholes International Airport (the terminal points of airway V- 70)-were equally divided among the airways for each airport in order to determine the potential number of operations along the V 70 airway. This is a very conservative assumption since general aviation aircraft mainly fly under Visual Flight Rules or Instrument Flight Rules condition and under new FAA regulations, most commercial and military aircraft will fly point to point rather than in specific airways.
2.2S.2.8 Projections of Industrial Growth Matagorda County does not have a Comprehensive County Plan or similar documentation. The Office of Economic Development has indicated that there are currently no known plans to develop any industrial facilities within five miles of the STP site. As previously noted, none of the current industries within the vicinity have any current plans for expansion.
2.2S.3 Evaluation of Potential Accidents The following site-specific supplement addresses COL License Information Item 2.7.
An evaluation of the information provided in Subsections 2.2S.1 and 2.2S.2, for potential accidents that should be considered as design basis events, and the potential effects of these accidents on the nuclear plant in terms of design parameters (e.g., overpressure, missile energies) and physical phenomena (e.g., concentration of flammable or toxic clouds outside building structures), was performed in accordance with the criteria in 10 CFR Parts 20, 52.17, 50.34, 100.20, and 100.21, using the guidance contained in Regulatory Guides (RG) 1.78, 1.91, 4.7, and 1.206.
2.2S.3.1 Determination of Design-Basis Events RG 1.206 states that design basis events, internal and external to the nuclear plant, are defined as those accidents that have a probability of occurrence on the order of magnitude of 10-7 per year or greater with potential consequences serious enough to affect the safety of the plant to the extent that the guidelines in 10 CFR Part 100 could be exceeded (Reference 2.2S-64). The following accident categories were considered in selecting design basis events: explosions, flammable vapor clouds (delayed ignition), toxic chemicals, fires, collisions with the intake structure, and liquid spills. The postulated accidents within these categories were analyzed at the following locations:
Nearby transportation routes (FM 521, the Colorado River, and Dow Pipeline Company natural gas transmission pipelines)
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Nearby chemical and fuel storage facilities (OXEA Corporation, Port of Bay City, Gulfstream Terminal and Marketing LLC and GulfMark Energy)
Onsite chemical storage (STP 1 & 2) - The chemicals used in STP 3 & 4 are similar to the chemicals used in STP 1 & 2 and are not stored any closer than the determined safe distances identified in the following subsections.
2.2S.3.1.1 Explosions Accidents involving detonations of explosives, munitions, chemicals, liquid fuels, and gaseous fuels were considered for facilities and activities either on site or within the vicinity of the plant, where such materials are processed, stored, used, or transported in quantity. The effects of explosions are a concern in analyzing structural response to blast pressures. The effects of blast pressure from explosions from nearby railways, highways, navigable waterways, or facilities to safety-related plant structures were evaluated to determine if the explosion would have an adverse effect on plant operation or would prevent safe shutdown of the plant.
The allowable and actual distances of hazardous chemicals transported or stored were evaluated in accordance with NRC RG 1.91, Revision 1, (RG 1.91) (References 2.2S- 41 and 2.2S-49). RG 1.91 cites one psi as a conservative value of peak positive incident overpressure, below which no significant damage would be expected. Conservative assumptions were used in determining the “safe distance” (i.e., the minimum separation distance required for an explosive force to not exceed one psi peak incident pressure). With the exception of the natural gas transmission pipeline, in each of the explosion scenario analyses, the volume of vapor at the upper flammability limit (UFL), specified in NUREG 1805 (Section 15.12(3)), capable of occupying the largest vessel was considered available for combustion and an explosion yield factor of 100% was applied to account for an in-vessel confined explosion (Reference 2.2S-65). In reality, only a small portion of the vapor within the flammability limits would be available for combustion and potential explosion, and a 100% yield factor is not achievable (Reference 2.2S-49). The yield factor is an estimation of the explosion efficiency, or a measure of the portion of the flammable material participating in the explosion. The onsite chemicals (Table 2.2S-6), offsite chemical storage (Table 2.2S-7), hazardous materials transported on navigable waterways (Table 2.2S-8), and hazardous materials potentially transported on FM 521 were evaluated to ascertain which hazardous materials had the potential to explode. The effects of these explosion events from both internal and external sources are summarized in Table 2.2S-9, and are described in the following subsections relative to the release source.
2.2S.3.1.1.1 Highways The nearest safety-related structure, the control building, is located more than 2700 feet away, at its closest point of approach, from FM 521. Industries in the area that use, store, and transport chemicals were contacted to identify their transportation routes and quantities of transported chemicals. As can be seen on Figure 2.1S-1, Texas State Highways 35 and 60, and US Highway 59 are the major transportation routes traversing the area. Highway transportation of large quantities of chemicals
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occur primarily on these routes. FM 521 is a rural road that can be used for local delivery, but is not expected to be used for large shipments of chemicals because it does not provide a direct route to or from any known chemical source or storage location. Therefore, using recognized quantity-distance relationships, it was determined that gasoline delivery tankers traveling on FM 521 provided the greatest danger from explosions on transportation routes within five miles of STP 3 & 4. Delivery of chemicals to the site was also evaluated, but determined to be bounded by the evaluation performed for the onsite storage quantities in Subsection 2.2S.3.1.1.4. The maximum quantity of the gasoline assumed to be transported on FM 521 was 50,000 pounds or 9000 gallons (RG 1.91). An evaluation was conducted using the TNT equivalency methodologies described in Subsection 2.2S.3.1.1. The results indicate that the safe distance for this quantity of gasoline is 266 feet, which is less than the minimum separation distance from the control building to the closest point of approach on FM 521, more than 2700 ft away (Table 2.2S-9). The STP 3 & 4 transmission lines cross FM 521 in four separate corridors, a single corridor to the west that is not credited as a required offsite source, a double corridor to the north containing three creditied offsite sources, and a single corridor to the east containing two credited offsite sources. The north and east corridors are separated on FM 521 by over one mile. Because of this separation, a gasoline tanker explosion on FM 521 under the north corridor transmission lines would not affect the eastern lines, nor would an explosion under the eastern lines affect the northern lines. Section 8.2 provides a description of the transmission corridors and Figure 1.2-37 shows where the transmission corridors cross FM 521. Therefore, an explosion from potentially transported hazardous materials on FM 521 would not adversely affect the safe operation or shutdown of STP 3 & 4.
2.2S.3.1.1.2 Pipelines Dow Pipeline Company operates two natural gas transmission pipelines within the vicinity of the STP site. The nearest safety-related structure, the control building, is more than 10,000 feet away from the analyzed release point, the closest approach of the nearest natural gas transmission pipeline. In order to conservatively evaluate a potential explosion from the natural gas transmission pipeline, a worst-case scenario was considered involving the immediate deflagration of the vapor coming out of the pipe creating an explosion and ensuing flare. In this scenario, it was assumed that the pipe had burst open, leaving the full cross-sectional area of the pipe completely exposed to the air. It was also assumed that the ignition source existed at the break point and that the duration of the release was 10 minutes. The safe distance to one psi overpressure was determined to be 7577 feet, which is less than the minimum separation distance to the control building of more than 10,000 ft away (Table 2.2S-9). The results indicate that overpressures from an explosion from a rupture in the Dow Pipeline Company natural gas transmission pipeline would not adversely affect the safe operation or shutdown of STP 3 & 4.
The chemical pipelines containing nitrogen, propylene, oxygen, and ethylene are treated as if the total quantity of the chemical gas in each of the pipelines is stored and released at the OXEA Corporation. These releases from the chemical pipelines were conservatively evaluated as continuous direct sources where the total quantity
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throughout the pipeline structure is released over a 10-minute period. The results are reported with the offsite chemical analysis in Table 2.2S-7.
2.2S.3.1.1.3 Waterway Traffic The nearest safety-related structure, the STP 3 Control Room, is located approximately 15,974 feet from the west bank of the Colorado River, a navigable waterway. From the Gulf Intracoastal Waterway, the river winds north along a 15.6- mile stretch until it approaches the turning basin located at the Port of Bay City facility, approximately 4.6 miles north-northeast of STP 3 & 4. The hazardous materials transported on barges and chemical parcel tankers that were identified for further analysis with regard to explosion potential were: n-butanol, isobutanol, acetic acid, n- butyl acetate, vinyl acetate, and gasoline. The maximum quantity of n-butanol, isobutanol, n-butyl acetate, and vinyl acetate assumed to be carried on a vessel is 380,000 gallons. The maximum quantity of acetic acid assumed to be carried on a single vessel is 500,000 gallons. The maximum quantity of gasoline assumed to be carried on a single vessel is 1,680,000 gallons. The results, using the conservative methodology described in Subsection 2.2S.3.1.1, indicate that the safe distances are less than the shortest distance between the STP 3 Control Room and the closest navigable point of approach on the Colorado River (Table 2.2S-9). The safe distances are:
n-butanol 896 feet isobutanol 888 feet acetic acid 814 feet n-butyl acetate 885 feet vinyl acetate 880 feet gasoline 1517 feet Therefore, an explosion from any of the identified chemicals potentially transported on navigable waters in the Colorado River would not adversely affect the safe operation or shutdown of STP 3 & 4.
2.2S.3.1.1.4 Onsite Chemical Storage/STP 1 & 2 STP 3 & 4 are located close to the existing STP 1 & 2 chemical storage locations. The hazardous materials stored on site that were identified for further analysis with regard to explosion potential were gasoline (12,000 gallon above ground storage tank), hydrazine, and hydrogen. A conservative analysis using the TNT equivalency methods described in Subsection 2.2S.3.1.1 was used to determine safe distances for the identified hazardous materials. The results indicate that the safe distances are less than the minimum separation distance from the nearest safety-related structure-the STP 3 Reactor Building-to each storage location. The safe distance for the 12,000- gallon gasoline tank is 296 feet; for hydrazine, 86 feet; and for hydrogen, 1048 feet (Table 2.2S-9). Gasoline is stored approximately 1771 feet; hydrazine approximately 2518 feet; and hydrogen 1563 feet; from the nearest safety-related structure-the STP 3 Reactor Building-for STP 3 & 4. Therefore, an explosion from any of the onsite
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hazardous materials evaluated would not adversely affect the safe operation or shutdown of STP 3 & 4. The chemicals used in STP 3 & 4 are similar to the chemicals used in STP 1 & 2 and are not stored any closer than the determined safe distances identified above.
2.2S.3.1.1.5 Offsite Facilities The OXEA Corporation, located approximately 22,841 feet, and the Port of Bay City, Gulfstream Terminal and Marketing LLC and GulfMark Energy facilities, located approximately 24,244 feet, from the nearest safety-related structure for STP 3 & 4-the STP 3 Control Room- are the facilities of concern within the vicinity of the STP site. The hazardous material stored at GulfMark Energy identified for further analysis with regard to explosion potential was crude petroleum. The gasoline storage at Gulfstream Terminal and Marketing LLC is bounded by the gasoline barge transported on the Colorado River which passes closer to STP 3 & 4. The hazardous materials stored at OXEA Corporation identified for further analysis were: 1-hexene, 1-octene, 2-hexene, acetaldehyde, acetic acid, acetone, cyclohexylamine, hydrazine, dimethyl sulfide, ethyl acetate, ethylene, hydrogen, isobutanol, isobutyl acetate, isobutyraldehyde, methane, n-butanol, n-butyl acetate, n-butyraldehyde, n-propyl acetate, n-propyl alcohol, propionaldehyde, propylene, and vinyl acetate. The results, using the methodology described in Subsection 2.2S.3.1.1, indicate that the safe distances are less than the minimum separation distances from the STP 3 Control Room to the storage locations for any of the identified chemicals (Table 2.2S-9). Propylene resulted in the largest safe distance, 8724 feet, which is less than the distance of 22,841 feet to the nearest safety-related structure for STP 3 & 4. Therefore, damaging overpressures from an explosion resulting from a complete tank or pipeline failure at the offsite facilities evaluated would not adversely affect the operation or shutdown of STP 3 & 4.
2.2S.3.1.2 Flammable Vapor Clouds (Delayed Ignition) Flammable materials in the liquid or gaseous state can form an unconfined vapor cloud that can drift towards the plant before an ignition event. Flammable chemicals released into the atmosphere can form vapor clouds, dispersing as they travel downwind. The portion of the cloud with a chemical concentration within the flammable range (i.e., between the LFL and UFL) may burn if the cloud encounters an ignition source. The speed at which the flame front moves through the cloud determines whether it is considered a deflagration or a detonation. If the cloud burns fast enough to create a detonation, an explosive force is generated.
The potential onsite chemical storage (Table 2.2S-6), offsite chemical storage (Table 2.2S-7), hazardous materials transported on navigable waterways (Table 2.2S-8), and hazardous materials transported on FM 521 were evaluated to ascertain which hazardous materials had the potential to form flammable vapor clouds and vapor cloud explosions. For those chemicals with an identified flammability range, the Areal Locations of Hazardous Atmospheres (ALOHA) Version 5.4.1, air dispersion model or the Dense Gas Dispersion (DEGADIS) model, Version 2.1, was used to determine the distances that the vapor cloud could exist in the flammability range, thus presenting the possibility of ignition and potential thermal radiation effects (Reference 2.2S-48 and 2.2S-58).
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The identified chemicals were then evaluated to determine the possible effects of a flammable vapor cloud explosion. For the gasoline barge on the Colorado River and the crude petroleum tank at GulfMark Energy, the safe distance for explosion was determined using the TNT equivalent methodologies presented in RG 1.91 and FM Global (Reference 2.2S-41 and Reference 2.2S-49). ALOHA was used to model the worst-case accidental vapor cloud explosion for the remaining identified chemicals, including the safe distances and overpressure effects at the nearest safety-related structure. To model the worst case in ALOHA, detonation was chosen as the ignition source. The safe distance was measured as the distance from the spill site to the location where the pressure wave is at one psi overpressure. Conservative assumptions were used in the ALOHA analyses for both meteorological inputs and identified scenarios. The following meteorological assumptions were used as inputs to the computer model, ALOHA: F (stable) stability class with a wind speed of one m/sec; ambient temperature of 25oC; relative humidity of 50%; cloud cover of 50%; and atmospheric pressure of one atmosphere. “F” stability and a wind speed of one m/sec represent the worst 5% of meteorological conditions observed at a majority of nuclear plant sites (Reference 2.2S-42 and 2.2S-61). For each of the identified chemicals in the liquid state, it was conservatively assumed that the entire contents of the vessel leaked, forming a one-centimeter-thick puddle where accommodated by the model. This provided a significant surface area from which to maximize evaporation and formation of a vapor cloud. For each of the identified chemicals in the gaseous state, it was conservatively assumed that the entire contents of the vessel/pipeline were released over a 10 minute period into the atmosphere as a continuous direct source (Reference 2.2S-47). The effects of flammable vapor clouds and vapor cloud explosions from internal and external sources are summarized in Table 2.2S-10 and are described in following subsections relative to the release source.
2.2S.3.1.2.1 Highways The nearest safety-related structure for STP 3 & 4, the control building, is located more than 2700 ft away at its closest distance to FM 521. The hazardous material potentially transported on FM 521 that was identified for further analysis with regard to the potential for forming a flammable vapor cloud capable of delayed ignition following an accidental release was gasoline. The methodology presented in Subsection 2.2S.3.1.2 was used for determining the distance from the accidental release site where the vapor cloud is within the flammability limits. It was conservatively estimated that the vessel carried and released 50,000 pounds or 9,000 gallons of the selected chemical. The results for the 9000-gallon gasoline tanker indicate that any plausible vapor cloud that can form and mix sufficiently under stable atmospheric conditions will have a concentration less than the LFL before reaching the control building. The distance to the LFL boundary for gasoline is 408 feet. Gasoline was also evaluated using the methodology presented in Subsection 2.2S.3.1.2 to determine the effects of a possible vapor cloud explosion. The safe distance, the minimum separation distance required for an explosion to have less than a one psi peak incident pressure impact from the drifted gasoline vapor cloud, is less than the shortest distance to the control building from any point on FM 521. The safe distance for this quantity of gasoline was determined to be 1035 feet (Table 2.2S-10). Therefore, a flammable vapor cloud
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ignition or explosion from a 9000-gallon gasoline tanker transported on FM 521, would not adversely affect the safe operation or shutdown of STP 3 & 4.
2.2S.3.1.2.2 Pipelines Dow Pipeline Company operates two natural gas transmission pipelines within the vicinity of the STP site. At its closest distance, these pipelines pass well beyond 10,000 feet of the nearest safety-related structure for STP 3 & 4-the control building. As described in Subsection 2.2S.3.1.1.2, the nearest Dow Pipeline Company natural gas transmission pipeline also represents the bounding design basis case for flammable vapor clouds and vapor cloud explosions. In order to conservatively evaluate the consequences from a potential flammable vapor cloud or vapor cloud explosion from a natural gas transmission pipeline, a worst-case scenario was considered involving the release of natural gas directly into the atmosphere resulting in a vapor cloud. As the modeled vapor cloud travels towards STP 3 & 4, it is plausible that the cloud concentration could become flammable along its path. The results indicate that under this scenario, the flammable vapor cloud does not exist at distances beyond 492 feet downwind (distance to LFL) from the pipe break and the ensuing explosion produces a peak incident pressure of one psi at a distance of 1002 feet. Therefore, the safe distance for the vapor cloud explosion is 1494 feet. This distance is significantly less than the distance from the pipeline to the nearest safety-related structure for STP 3 & 4. Therefore, a flammable vapor cloud ignition or explosion from a rupture in the Dow Pipeline Company natural gas transmission pipeline would not adversely affect the safe operation or shutdown of STP 3 & 4 (Table 2.2S-10). As discussed in Subsection 2.2S.3.1.1.2, the chemical pipelines are conservatively treated as if the total quantity of the chemical was stored and released at the OXEA Corporation. The results are reported with the offsite chemical analyses in Subsection 2.2S.3.1.2.5.
2.2S.3.1.2.3 Waterway Traffic The nearest safety-related structure for STP 3 & 4-the STP 3 Control Room-is located approximately 15,974 feet from the west bank of the Colorado River, a navigable waterway. The hazardous materials transported on barges or chemical parcel tankers that were identified for further analysis with regard to forming a flammable vapor cloud capable of delayed ignition following an accidental release are: n-butanol, isobutanol, acetic acid, n-butyl acetate, vinyl acetate, and gasoline. An analysis was conducted for the identified hazardous materials. The conservative methodology presented in Subsection 2.2S.3.1.2 was used to determine the distance the formed vapor cloud could travel before ignition (the LFL boundary) using the ALOHA or DEGADIS dispersion modeling. The maximum quantity of n-butanol, isobutanol, n-butyl acetate, and vinyl acetate assumed to be spilled on the waterway was 380,000 gallons. The quantity of acetic acid assumed to be spilled on the waterway was 500,000 gallons. For these cases, the maximum surface area of the spill that ALOHA would accommodate-31,400 m2-was used. The maximum quantity of gasoline assumed to be spilled on the waterway was 1,680,000 gallons. Due to the immense volume of gasoline-1,680,000 gallons-the maximum spill area for a one-centimeter-thick depth would require the gasoline to flow miles down the river away from STP 3 & 4. Therefore, the length of the spill area influencing the STP 3 Control Room was
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assumed to be 1500 feet up and down the Colorado River from the spill site, the closest point from the Colorado River to STP 3 & 4, for a total of 3000 feet in river length. The results indicate that any plausible vapor cloud that can form and mix sufficiently under stable atmospheric conditions will be below the LFL boundary before reaching the nearest safety-related structure for STP 3 & 4. The resultant vinyl acetate and gasoline vapor clouds resulted in the largest traveled distances prior to reaching the LFL boundary. The distance to the LFL boundary for vinyl acetate is 1812 feet, and 5605 feet for gasoline (Table 2.2S-10).
Because each of the identified chemicals has the potential to explode, a vapor cloud explosion analysis was also performed as described in Subsection 2.2S.3.1.2. Results for the vapor cloud explosion analysis indicate that the safe distances, the minimum distances, with drift taken into consideration, required for an explosion to have less than a one psi peak incident pressure, are less than the shortest distance to the nearest safety-related structure for STP 3 & 4 from a probable release point on the Colorado River. The safe distance for vinyl acetate is 3570 feet; for gasoline, 8642 feet; for n-butanol, 1593 feet; for isobutanol 1848 feet; and for n-butyl acetate 1974 feet. For acetic acid, no explosion occurs because the vapor cloud never reached concentrations between the UFL and LFL (Table 2.2S-10). Therefore, a flammable vapor cloud with the possibility of ignition or explosion from a transported hazardous material on the Colorado River would not adversely affect the safe operation or shutdown of STP 3 & 4.
2.2S.3.1.2.4 Onsite Chemical Storage/STP 1 & 2 STP 3 & 4 are close to the existing STP 1 & 2 chemical storage locations. The hazardous materials stored onsite that were identified for further analysis with regard to forming a flammable vapor cloud capable of delayed ignition following an accidental release of the hazardous material were gasoline, hydrazine, and hydrogen. As described in Subsection 2.2S.3.1.2, dispersion models were used to determine the distance a vapor cloud can travel to reach the LFL boundary once a vapor cloud has formed from an accidental release of the identified chemical. It was conservatively assumed that the entire contents of the gasoline and hydrazine vessels leaked forming a one-centimeter-thick puddle; while, for hydrogen, it was assumed that the entire contents of the tank were released over a 10-minute period as a continuous direct source. The results indicate that any plausible vapor cloud that could form and mix sufficiently under stable atmospheric conditions would be below the LFL boundary before reaching the nearest safety-related structure-the STP 3 Reactor Building. The distance to the LFL boundary for gasoline is 480 feet; for hydrogen, 1362 feet; and for hydrazine the distance to the LFL boundary is less than 33 feet. Gasoline is stored approximately 1771 feet; hydrogen, approximately 1563 feet; and hydrazine approximately 2518 feet from the STP 3 Reactor Building (Table 2.2S-10).
A vapor cloud explosion analysis was also completed as detailed in Subsection 2.2S.3.1.2 in order to obtain safe distances. The results indicate that the safe distances, the minimum distance required for an explosion to have less than a one psi peak incident pressure, are less than the shortest distance to the nearest safety- related structure for STP 3 & 4-the STP 3 Reactor Building-and the storage location of
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these chemicals. The safe distance for the 12,000-gallon gasoline tank is 1200 feet; for hydrogen, 1557 feet; and for hydrazine, no explosion occurs. For hydrazine, no explosion occurs because the vapor pressure for hydrazine is sufficiently low enough that not enough vapor is released from the spill for a vapor cloud explosion to occur. Each of these chemicals is stored at a greater distance. Gasoline is stored at approximately 1771 feet; hydrogen approximately 1563 feet; and hydrazine approximately 2518 feet from the nearest safety-related structure-the STP 3 Reactor Building. Therefore, a flammable vapor cloud with the possibility of ignition or explosion formed from the storage of the onsite chemicals analyzed would not adversely affect the safe operation or shutdown of STP 3 & 4 (Table 2.2S-10).
2.2S.3.1.2.5 Offsite Facilities The OXEA Corporation located approximately 22,841 feet, and the Port of Bay City, Gulfstream Terminal and Marketing LLC and GulfMark Energy facilities, located approximately 24,244 feet, from the nearest safety-related structure-the STP 3 Control Room- operate within the vicinity of the STP site. The hazardous material stored at GulfMark Energy that was identified for further analysis with regard to the potential for delayed ignition of a flammable vapor cloud formed following the accidental release of the hazardous material was crude petroleum--the gasoline storage at the Port of Bay City, Gulfstream Terminal and Marketing LLC and GulfMark Energy is bounded by the gasoline transport on the Colorado River. The hazardous materials stored at OXEA Corporation that were identified for further analysis with regard to the potential for delayed ignition of flammable vapor clouds are: 1-hexene, 1-octene, 2-hexene, acetaldehyde, acetic acid, acetone, cyclohexylamine, hydrazine, carbon monoxide, dimethyl sulfide, ethyl acetate, ethylene, hydrogen, isobutanol, isobutyl acetate, isobutyraldehyde, methane, n-butanol, n-butyl acetate, n-butyraldehyde, n-heptanal, n-propyl acetate, n-propyl alcohol, propionaldehyde, propylene, and vinyl acetate. For 1-octene, 2-hexene, acetaldehyde, acetic acid, isobutanol, isobutyl acetate, isobutyraldehyde, n-butanol, n-butyl acetate, n-butyraldehyde, n-propyl acetate, n- propyl alcohol, propionaldehyde, and vinyl acetate, the maximum allowable surface area of the spill that ALOHA would allow-31,400 m2-was used due to the large storage quantity of these chemicals. The 1-hexene storage tank at OXEA Corporation is surrounded by an installed berm; therefore, it was assumed that the berm confined the spill, limiting the surface area of the spill to 10,800 ft2. For the remaining chemicals, it was conservatively assumed that the entire contents of the vessels leaked and formed a one-centimeter-thick puddle, or in the case of the chemicals in the gas state, the entire contents of the tank or pipeline were released over a 10-minute period as a continuous direct source. The results using the methodology described in Subsection 2.2S.3.1.2 indicate that any plausible vapor cloud that could form and mix sufficiently under stable atmospheric conditions would be below the LFL boundary before reaching STP 3 & 4 (Table 2.2S-10). The greatest distance to the LFL boundary- 12,672 feet-was for hydrogen and ethylene.
Because each of the identified chemicals has the potential to explode, a vapor cloud explosion analysis was also performed as described in Subsection 2.2S.3.1.2. The results of the vapor cloud explosion analysis indicate that the safe distances-the minimum distances required for an explosion to have less than a one psi peak incident
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pressure-are less than the minimum separation distance between the STP 3 Control Room and the release points at OXEA Corporation and GulfMark Energy. The largest determined safe distance was for ethylene, 14,784 feet. Therefore, a flammable vapor cloud with the possibility of ignition or explosion from the storage of chemicals at offsite facilities would not adversely affect the safe operation or shutdown of STP 3 & 4.
2.2S.3.1.3 Toxic Chemicals Accidents involving the release of toxic chemicals from onsite storage facilities and nearby mobile and stationary sources were considered. Toxic chemicals known to be present onsite or in the vicinity of the STP site, or to be frequently transported in the vicinity were evaluated. NRC RG 1.78, Rev. 1, requires evaluation of Control Room habitability following a postulated external release of hazardous chemicals from mobile or stationary sources, on site or offsite (Reference 2.2S-42).
The potential onsite chemicals (Table 2.2S-6), offsite chemical storage (Table 2.2S-7), hazardous materials transported on navigable waterways (Table 2.2S-8), and hazardous materials potentially transported on FM 521 were evaluated to ascertain which hazardous materials should be analyzed with respect to their potential to form a toxic vapor cloud following an accidental release. The ALOHA air dispersion model was used to predict the concentrations of toxic chemical clouds as they disperse downwind for all facilities and sources except for the gasoline barge, which was analyzed using the Toxic Dispersion Model (TOXDISP), Revision 3, and for carbon monoxide at the OXEA Corporation, which was analyzed using the Flame Acceleration Simulator (FLACS) computer model (Reference 2.2S-68). The maximum distance a cloud can travel before it disperses enough to fall below the Immediately Dangerous to Life and Health (IDLH) concentration in the vapor cloud was determined using ALOHA or TOXDISP or FLACS. The ALOHA model was also used to predict the concentration of the chemical in the Control Room following a chemical release to ensure that, under worst-case scenarios, Control Room operators will have sufficient time to take appropriate action.
The IDLH is defined by the National Institute of Occupational Safety and Health as a situation that poses a threat of exposure that is likely to cause death or immediate or delayed permanent adverse health effects, or one that could prevent escape from such an environment. The IDLHs determined by the National Institute of Occupational Safety and Health are established such that workers are able to escape such environments without suffering permanent health damage. Where an IDLH was unavailable for a toxic chemical, the time-weighted average (TWA) or threshold limit value (TLV), promulgated by the Occupational Safety and Health Administration or adopted by the American Conference of Governmental Hygienists, or the Temporary Emergency Exposure Limit, adopted by the U.S. Department of Energy, were used as the toxicity concentration level. Conservative meteorological assumptions were used: F (stable) stability class with a wind speed of one m/sec; ambient temperature of 25°C; relative humidity of 50%; cloud cover of 50%; and atmospheric pressure of one atmosphere. A Pasquill stability category “F” and a wind speed of one m/sec typically represent the worst five percent of meteorological conditions observed at a majority of nuclear plant sites (Reference 2.2S-42 and 2.2S-61). It was further assumed that the
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toxic vapor cloud traveled downwind directly toward the Control Room. Additionally, a meteorological sensitivity analysis was conducted using the ALOHA model for four of the toxic chemicals listed on Table 2.2S-11 involving five postulated events.
For each of the identified chemicals, it was conservatively assumed that the entire contents of the vessel leaked, forming a one-centimeter-thick puddle, where accommodated by the model. For those identified hazardous materials in the gaseous state, it was conservatively assumed that the entire contents of the vessel or pipeline were released over a 10-minute period into the atmosphere as a continuous direct source (Reference 2.2S-47). The effects of toxic chemical releases from internal and external sources are summarized in Table 2.2S-11 and are described in the following subsections relative to the release sources.
2.2S.3.1.3.1 Highways The nearest Control Room for STP 3 & 4 is located approximately 2853 feet at its closest distance to FM 521. Gasoline was the hazardous material potentially transported on FM 521 that was identified for further analysis with regard to the potential of forming a toxic vapor cloud following an accidental release and able to travel to the Control Room. The methodology presented in Subsection 2.2S.3.1.3 was used for determining the distance from the release site to the point where the toxic vapor cloud reaches the IDLH boundary. For gasoline, the TWA toxicity limit was conservatively used because no IDLH is available for this hazardous material. The TWA is the average value of exposure over the course of an eight-hour work shift. The maximum concentration of gasoline attained in the Control Room during the first hour of the release was determined. In this scenario, it was conservatively estimated that the transport vehicle lost the entire contents-50,000 pounds or 9000 gallons. The results indicate that any vapor cloud that forms following an accidental release of gasoline on FM 521 and travels toward the Control Room would not achieve an airborne concentration greater than the TWA in the Control Room (Table 2.2S-11). Therefore, the formation of a toxic vapor cloud following an accidental release of gasoline transported on FM 521 would not adversely affect the safe operation or shutdown of STP 3 & 4.
2.2S.3.1.3.2 Pipelines The Dow Pipeline Company operates two natural gas transmission pipelines within the vicinity of the STP site. At its closest distance, these pipelines pass within approximately 11,089 feet of the nearest Control Room for STP 3 & 4. The Dow Pipeline Company natural gas transmission pipelines carry natural gas and are not expected to carry a different product in the future. Natural gas is not considered toxic and there is no IDLH or other toxicity limit identified for this chemical. Therefore, no toxicity analysis is necessary for the natural gas transmission pipelines. As discussed in Subsection 2.2S.3.1.1.2, the chemical pipelines are conservatively treated as if the total quantity of the chemical was stored and released at the OXEA Corporation. The results are reported with the offsite chemical analyses in Subsection 2.2S.3.1.3.5.
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2.2S.3.1.3.3 Waterway Traffic The STP 3 Control Room is located approximately 15,974 feet from the west bank of the Colorado River, a navigable waterway. The plausible chemicals transported on barges or chemical parcel tankers along the Colorado River identified for further analysis with regard to the potential of forming a toxic vapor cloud following an accidental release and traveling toward the Control Room are n-butanol, isobutanol, acetic acid, n-butyl acetate, vinyl acetate, and gasoline. An analysis was conducted for the identified hazardous materials. The conservative methodology outlined in Subsection 2.2S.3.1.3 was used to determine the concentration of a toxic chemical cloud as it disperses downwind toward the Control Room using the ALOHA or TOXDISP dispersion modeling. The maximum quantity of n-butanol, isobutanol, n- butyl acetate, and vinyl acetate assumed to be spilled on the waterway was 380,000 gallons. The quantity of acetic acid assumed to be spilled on the waterway was 500,000 gallons. For these cases, the maximum surface area of the spill that ALOHA would accommodate-31,400 m2-was used. The maximum quantity of gasoline assumed to be spilled on the waterway was 1,680,000 gallons. Due to the immense volume of gasoline-1,680,000 gallons-the maximum spill area for a one-centimeter- thick depth would require the gasoline to flow miles down the river away from STP 3 & 4. Therefore, the length of the spill area influencing the Control Room was assumed to be 1500 feet up and down the river from the spill site, the closest point from the river to STP 3 & 4, for a total of 3000 feet in river length. The Control Room concentrations of the selected hazardous materials never reach the IDLH or other established toxicity limits (Table 2.2S-11). The greatest distance to an IDLH for the selected hazardous materials was vinyl acetate, where its concentration in the air disperses to a level below its IDLH limit 10,032 feet from the spill site. Therefore, the formation of a toxic vapor cloud following an accidental release of the analyzed hazardous materials transported on the Colorado River would not adversely affect the safe operation or shutdown of STP 3 & 4.
Additionally, a meteorological sensitivity analysis using ALOHA was performed for two of the chemicals transported by barge, acetic acid and gasoline. The ALOHA model was used to perform the meteorological sensitivity analysis for gasoline using n-Heptane as a surrogate for gasoline. The maximum surface area of the spill that ALOHA would accommodate for the gasoline sensitivity analysis-31,400 m2-was used. The results of the gasoline sensitivity analysis indicate that under the determined worst case meteorological conditions, the distance to the TLV-TWA was 5,808 feet and the maximum concentration reached in the control room was 13.8 ppm.
2.2S.3.1.3.4 Onsite Chemical Storage/STP 1 & 2 The hazardous materials stored on site that were identified for further analysis with regard to the potential of the formation of toxic vapor clouds formed following an accidental release were Freon-11, Freon-12, gasoline (12,000 gallon above ground storage tank), Halon 1301, hydrogen (asphyxiant), sodium hypochlorite, monoethanolamine, hydrazine, nitrogen (asphyxiant), and liquid nitrogen (asphyxiant). As described in Subsection 2.2S.3.1.3, the identified hazardous materials were analyzed using the ALOHA dispersion model to determine whether the formed vapor cloud would reach the Control Room intake and what the concentration of the toxic
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chemical would be in the Control Room following an accidental release. Additionally, a meteorological sensitivity analysis was performed for sodium hypochlorite using the ALOHA model. Hydrogen, nitrogen, and liquid nitrogen concentrations were determined at the Control Room following a 10-minute release from the largest storage vessel. In each case, the concentration of these asphyxiants at the Control Room- 1490 ppm hydrogen, 5540 ppm nitrogen, and 1390 ppm liquid nitrogen-would not displace enough oxygen for the Control Room to become an oxygen-deficient environment, nor would they be otherwise toxic at these concentrations (Reference 2.2S-63). The remaining chemical analyses indicate that the Control Room would remain habitable for the worst-case release scenario. (While, the distance to the selected toxicity limit for gasoline is greater than the distance to the STP 3 & 4 control room, the concentration inside the control room never reached the toxicity limit.) The worst-case release scenario in each of the analyses included the total loss of the largest vessel, resulting in an unconfined one-centimeter-thick puddle under stable atmospheric conditions (Table 2.2S-11). Therefore, the formation of a toxic vapor cloud following an accidental release of the analyzed hazardous materials stored onsite would not adversely affect the safe operation or shutdown of STP 3 & 4.
2.2S.3.1.3.5 Offsite Facilities The OXEA Corporation, located approximately 22,841 feet, and the Port of Bay City, Gulfstream Terminal and Marketing LLC and GulfMark Energy facilities, located approximately 24,244 feet, from STP 3 & 4 operate within the vicinity of the STP site. The hazardous material stored at GulfMark Energy that was identified for further analysis with regard to the potential for forming a toxic vapor cloud following an accidental release and traveling to the Control Room was crude petroleum. (The gasoline storage at the Port of Bay City, Gulfstream Terminal and Marketing LLC, and GulfMark Energy is bounded by gasoline transport on the Colorado River.) The hazardous materials stored at OXEA Corporation that were identified for further analysis with regard to the potential for forming a toxic vapor cloud following an accidental release and traveling toward the Control Room were 1-hexene, 1-octene, 2- hexene, acetaldehyde, acetic acid, acetone, cyclohexylamine, dimethyl sulfide, hydrazine, sodium hypochlorite, carbon dioxide (asphyxiant), carbon monoxide (asphyxiant), ethyl acetate, ethylene (asphyxiant), hydrogen (asphyxiant), isobutanol, isobutyl acetate, isobutyraldehyde, methane (asphyxiant), n-butanol, n-butyl acetate, n-butyraldehyde, n-propyl acetate, n-propyl alcohol, propionaldehyde, nitrogen (asphyxiant), propylene (asphyxiant), and vinyl acetate. Additionally, a meteorological sensitivity analysis was performed for acetic acid and 1-hexene using the ALOHA model. Carbon dioxide, carbon monoxide, ethylene, hydrogen, methane, nitrogen and propylene concentrations were determined outside the Control Room following a 10- minute release from the largest storage vessel. In each case, the concentration of the asphyxiants at the Control Room would not displace enough oxygen for the Control Room to become an oxygen-deficient environment, nor would it be otherwise toxic at these concentrations (Table 2.2S-11). The remaining chemical analyses indicate that the distance the vapor cloud could travel prior to falling below the selected toxicity limit was less than the distance to the Control Room. Therefore, the formation of a toxic vapor cloud following an accidental release of the analyzed hazardous materials stored offsite would not adversely affect the safe operation or shutdown of STP 3 & 4.
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2.2S.3.1.4 Fires Accidents were considered in the vicinity of the STP that could lead to high heat fluxes or smoke, and nonflammable gas or chemical-bearing clouds from the release of materials as a consequence of fires. Fires in adjacent industrial plants and storage facilities-chemical, oil and gas pipelines; brush and forest fires; and fires from transportation accidents-were evaluated as events that could lead to high heat fluxes or to the formation of such clouds. The nearest industrial sites are the OXEA Corporation and the Port of Bay City, Gulfstream Terminal and Marketing LLC, and GulfMark Energy facilities, located approximately 4.6 miles north-northeast from STP 3 & 4. Each of the chemicals stored at the OXEA Corporation and Port of Bay City facilities, along with the nearest Dow Pipeline Company natural gas transmission pipeline, and those chemicals transported by barge on the Colorado River, were evaluated in Subsection 2.2S.3.1.2 for potential effects of accidental releases leading to a delayed ignition and/or explosion of any formed vapor cloud. For each of the stored or transported hazardous materials evaluated, the results indicated that any formed vapor cloud would dissipate below the LFL before reaching the Control Room. Therefore, it is not expected that there would be any hazardous effects to STP 3 & 4 from fires or heat fluxes associated with the operations at these facilities, transportation routes, pipelines, or barge routes.
Further, the potential for brush, forest or woodland, and onsite fires from storage facilities was evaluated. A cleared area at least 1950 feet wide to the north, south, and west of STP 3 & 4 provides a substantial defensible zone in the unlikely event of a fire originating in brush or spreading to the site as a result of onsite or offsite activities. Additionally, the area to the east of STP 3 & 4 comprises the switchyard and contains no appreciable brush or trees. Therefore, the zone surrounding STP 3 & 4 is of sufficient size to afford protection in the event of a fire. For perspective, the Texas Department of Public Safety recommends a safety zone of only 30 to 50 feet be maintained around structures for protection against wildfires, while California has adopted regulations requiring a fire break of at least 30 feet and a fuel break to 100 feet (Reference 2.2S-50 and 2.2S-51). The safety zone around STP 3 & 4 greatly exceeds these recommended distances, and therefore, it is not expected that there will be any hazardous effects to STP 3 & 4 from fires or heat fluxes associated with wild fires, fires in adjacent industrial plants, or from onsite storage facilities.
2.2S.3.1.5 Collisions with Intake Structure Because STP is located near a navigable waterway, an evaluation was performed that considered the probability and potential effects of impact on the plant cooling water intake structure and enclosed pumps. Although, makeup water for the onsite main cooling water reservoir for STP 3 & 4 is taken from the Colorado River for normal plant operation, the separate ultimate heat sink, which is not supplied directly from the intake structure on the Colorado River, provides cooling water for the safe shutdown of the plant. Thus, damage to the Colorado River makeup water intake structure would not affect the safe shutdown of STP 3 & 4.
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2.2S.3.1.6 Liquid Spills The accidental release of oil or liquids that may be corrosive, cryogenic, or coagulant were considered to determine if the potential exists for such liquids to be drawn into the plant's makeup water intake structure and circulating water system or otherwise affect the plant's safe operation. In the event that these liquids would spill into the Colorado River, they would not only be diluted by the large quantity of Colorado River water, but the makeup water intake from the Colorado River is not necessary for the safe shutdown of the plant. Therefore, any spill in the Colorado River would not affect the safe operation or shutdown of STP 3 & 4.
2.2S.3.1.7 Radiological Hazards The release of radioactive material from STP 1 & 2, as a result of normal operations or as a result of an unanticipated event, would not threaten the safety of STP 3 & 4. The Control Room habitability system for the ABWR provides the capability to detect and protect main Control Room personnel from airborne radioactivity. In addition, safety- related structures, systems, and components for the ABWR have been designed to withstand the effects of radiological events and the consequential releases that would bound the contamination from a release from either of these potential sources.
2.2S.3.2 Effects of Design Basis Events As concluded in the previous subsections, no events were identified that had a probability of occurrence of greater than 1.0E-7 per year, or potential consequences serious enough to affect the safety of the plant to the extent that the guidelines in 10 CFR Part 100 could be exceeded. Thus, there are no accidents associated with nearby industrial, transportation, or military facilities that are considered design basis events.
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2.2S-58 Dense Gas Air Dispersion Model (DEGADIS) (EV 112), Rev. 2.1, User's Guide for the DEGADIS 2.1 Dense Gas Dispersion Model, Report to U.S. EPA, NTIS PB90-213893, 1989.
2.2S-59 "Material Safety Data Sheet," Alfa Aesae, A Johnson Matthey Company, July 24, 2007.
2.2S-60 "Material Safety Data Sheet," Acros Organics BVBA, A Division of ThermoFishcher Scientific, Fax-On-Demand Document Retrieval System, July 24, 2007.
2.2S-61 "Nuclear Power Plant Control Room Ventilation System Design for Meeting General Criterion 19, " Murphy, K. G. and K. M. Campe, U.S. Atomic Energy Commission, 13th AEC Air Cleaning Conference, 1974.
2.2S-62 Santos USA Corporation, Pipeline Attributes, Railroad Commission of Texas. Available at http://gis2.rrc.state.tx.us/public/, accessed June 29, 2007.
2.2S-63 "Respiratory Protection," Title 29 Code of Federal Regulations Part 1910.134, July 2002.
2.2S-64 "Combined License Applications for Nuclear Power Plants," Regulatory Guide 1.206, Revision 1, June 2007.
2.2S-65 "Fire Dynamics Tools (FDTs) Quantitative Fire Hazard Analysis Methods for the U.S. Nuclear Regulatory Commission Fire Protection Inspection Program," NUREG-1805, December 2004.
2.2S-66 "Material Safety Data Sheet," Bedoukian Research, Inc., July 24, 2007.
2.2S-67 "Material Safety Data Sheet," Arkema Canada, Inc., March 15, 2006.
2.2S-68 Flame Acceleration Simulator (FLACS) User’s Guide, Gexcon, 2003.
Nearby Industrial, Transportation, and Military Facilities 2.2S-31 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.2S-1 Description of Facilities - Products and Materials Number of Persons Major Products or Site Concise Description Primary Function Employed Materials OXEA OXEA Corporation Manufacturer of 260 Basic organic Corporation receives raw chemicals organic chemicals, chemicals, from rail, pipeline, road, crudes, organic industrial organic and by barge and dyes & pigments chemicals, manufactures basic and acetates, industrial aldehydes, crudes, chemicals/compounds intermediates, dyes and pigments STP 1 & 2 STP 1 & 2 are each 1329 Power Production About 1300 Electric Power MWe Westinghouse Electric Company, LLC pressurized water reactors licensed by the NRC Port of Bay City/ Petroleum Transit Station Receive, store, & 4 Gasoline; Diesel oil Gulfstream transfer petroleum Terminal and products Marketing LLC Port of Bay City/ Petroleum Transit Station Receive, store, & None Petroleum Crude GulfMark Energy transfer petroleum Oil products Equistar Equistar receives raw Manufacturer of 194 HDPE plastic resins chemicals from both rail HDPE plastic resins and road and manufactures HDPE plastic resins Matagorda Waste Water supply and Sanitary 3N/A Disposal and sanitary wastewater wastewater Water Supply treatment plant treatment plant Corporation
2.2S-32 Nearby Industrial, Transportation, and Military Facilities Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.2S-2 STP Onsite Chemical Storage Maximum Quantity in Largest Compound IDLH [1] Container (lbs) Storage Location Sodium Bromide None 37,800 ECW/CWI Hypochlorite Tank established Sulfuric Acid 15 mg/m3 105,000 E/M Shop Bldg. 19, WSHE-32 Bldg. 19, WSHE-19, MEAB 1 & 2, TGB 1 & 2, EM Shop Unit 1 demineralizer Area, Neutralization basin Plant Demin Area Unit 1 NE Corner outside Unit 2 NE Corner Outside, acid storage Acid Storage Unit 2 P/D Lab Bldg 52 Boric Acid None 44,100 Bldg. 27, WSHE-32 established Unit 1/2 MEAB 50% Sodium Hydroxide None 67,200 Units 1 & 2 Demineralizer established Bldg. 19, WSHE-32 Caustic Storage Units 1 & 2 Unit 1 & 2 MEAB & TGB Bldg 44 Nuclear Training Bldg 27, WSHE 32 Number 2 Diesel Fuel None 588,000 EGDS, DGB Unit 1 & 2, Fire Pump House, established NSC EGDS, Unit 2, NTF Bldg-44, Gas Island Unit 2 Emergency Generator Bldg 20 Fab Shop, MOF Tool Room Freon-11 2000 ppm 2917 Bldg 19 Fab Shop, Bldg 27 WSHE 32 (Trichlorofluoromethane) Electric Shop, Bldg 19 WSHE 32 Bldg 19 WHSE 32 Freon-12 15,000 ppm 55,200 Bldg 20 Fab Shop (Dichlorodifluoromethane) E/M Shop, Bldg 27 WSHE 32 Bldg 19 WHSE 32
Nearby Industrial, Transportation, and Military Facilities 2.2S-33 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.2S-2 STP Onsite Chemical Storage (Continued) Maximum Quantity in Largest Compound IDLH [1] Container (lbs) Storage Location Fryquel EHC 1000 mg/m3 4200 Bldg. 27, WSHE-32, MM shop as Triphenyl Units 1 & 2 TGB Phosphate Mechanics Shop Units 1 & 2 TGB, Bldg 19, WHSE 32 WHSE-32 Compressed Gas Storage Gasoline No IDLH 12,000 gallons Gas Service Island (aboveground tank) listed; 300 Electric Shop, Bldg 20 Fab Shop ppm TWA [2] Halon 1301 40,000 ppm 9150 Vault (Trifluorobromomethane) Bldg-44 NTF Unit 1 & 2 MEAB Hydrogen None 100,200 ft3/ Main Gas Storage established- bank; 8,350 ft3/ asphyxiant cylinder 12.5% Sodium None 7200 gallons Cooling water intake/N/W ECW Intake Hypochlorite established- Bldg. 19, WHSE-32 10 ppm as chlorine Hydrazine 50 ppm 1260 South of TBG 1 & 2, Bldg-19, WHSE-32 Aux Boiler, Bldg-19, WHSE-32 Monoethanolamine 30 ppm 126,000 SW of TGB 1 & 2 Ethanolamine Storage Tank Nitrogen None 20,000 Bldg 20 Fab Shop, Bldg 20 Yard, Bldg 27 established- WHSE-32 asphyxiant Cold Chem Labs, Electric Shop Met Lab, Unit 1 MEAB & TGB, I&C Shop Unit 1 & 2 MEAB &TGB, Switch Yard Bulk Nitrogen Storage MM Shop Liquid Nitrogen None 92,400 North of Unit 2 Outside protected area established - asphyxiant Source - References 2.2S-32, 2.2S-37 through 2.2S-40, and 2.2S-52
[1] IDLH, Immediately Dangerous to Life or Health [2] TWA, Time-Weighted Average
2.2S-34 Nearby Industrial, Transportation, and Military Facilities Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.2S-3 Offsite Chemical Storage - OXEA Corporation, Gulfstream Terminal and Marketing LLC, and GulfMark Energy Maximum Quantity [1] in Largest Container Material Toxicity Limit (IDLH) [2] (lbs) OXEA Corporation 1-Hexene 30 ppm TEEL [4] 1,265,000 1-Octene 250 mg/m3 TEEL [4] 2,010,000 2-Hexene 30 ppm TLV-TWA [3] 3861 2-Methyl Hexanoic Acid None established 2700 Acetaldehyde 2,000 ppm 866,295 Acetic Acid 50 ppm 9,999,999* Acetone 2500 ppm 4400 Nickel Catalyst 10 mg/m3 10,000 Amercor 8780 Cyclohexylamine 30 ppm-TEEL [4] 4000 Amerzine 35 Hydrazine 50 ppm 4000 ATC-AFFF Foam -2-(2-Butoxyethoxy) None established 30,000 Sodium Hypochlorite 10 ppm as chlorine 30,000 Aluminum Oxide Catalyst (85% None established 10,000 Aluminum Oxide) Iron Oxide Catalyst (90% iron oxide) 2500 mg/m3 8000 Zinc Oxide Catalyst (50%) 500 mg/m3 10,000 C7 heavy ends (C-14 Esters, 71%) None established 11,520 C8 Catalyst None established 10,000 C9 heavy ends (C-18 Esters, 71%) None established 11,520 Carbon Dioxide 40,000 ppm 868,000 Carbon Monoxide 1200 ppm 868,000 Celite (Diatomaceous Earth) 3000 mg/m3 10,000 Silver (catalyst) 10 mg/m3 12,250 Silica 3000 mg/m3 10,000 Aluminum Silicate 10 mg/m3-TLV [3] 40,000 Diesel None established 40,000 Diisopropanolamine None established 32,000 Dimethyl Sulfide 2000 ppm -TEEL [4] 10,000 Drewfloc 2449 (33% Petroleum Distillate) 1000 ppm 4000 Drewsperse 2625B (Potassium None established 32,000 Hydroxide)
Nearby Industrial, Transportation, and Military Facilities 2.2S-35 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.2S-3 Offsite Chemical Storage - OXEA Corporation, Gulfstream Terminal and Marketing LLC, and GulfMark Energy (Continued) Maximum Quantity [1] in Largest Container Material Toxicity Limit (IDLH) [2] (lbs) Ethyl Acetate 2000 ppm 21,800 Ethylene 15,000 ppm - TEEL [4] 470,000 Ethylene Glycol None established 64,000 G-132 D catalyst (copper oxide 50%) 100 mg/m3 8,000 G55/G65 Catalyst (aluminum oxide 70%) None established 10,000 Gasoline 300 ppm -TWA [3] 14,400 Calcium Carbonate 10 mg/m3 5,000 Hexanoic Acid None established 99,999* Hydrogen Asphyxiant 58,512 Hydroquinone 50 mg/m3 3,000 Isobutanol 1600 ppm 3,455,333 Isobutyl acetate 1300 ppm 9,999,999* Isobutyraldehyde 1500 ppm -TEEL [4] 999,999* Sulfuric Acid 15 mg/m3 As Batteries Calcium Oxide (Dust) 25 mg/m3 40,000 Methane 25,000 ppm -TEEL [4] 47,000 Methane Sulfonic Acid None established 9,999* Monoethanolamine 30 ppm 99,999* N-Butanol 1400 ppm 16,921,268 N-butyl acetate 1700 ppm 9,999,999* N-Butyraldehyde 2000 ppm - TEEL [4] 3,300,000 N-Heptanal None established 325,000 N-Heptanoic acid None established 1,929,855 N-Nonanal None established 400,000 N-Propyl acetate 1700 ppm 9,999,999* N-Propyl alcohol 800 ppm 9,999,999* Nitrogen Asphyxiant 9,999,999* Nonanoic acid None established 9,999,999* Oxygen None established 999,999* Parabenzoquinone 100 mg/m3 99,999* Phosphoric acid (85%) 1000 mg/m3 99,999* Potassium acetate None established 99,999*
2.2S-36 Nearby Industrial, Transportation, and Military Facilities Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.2S-3 Offsite Chemical Storage - OXEA Corporation, Gulfstream Terminal and Marketing LLC, and GulfMark Energy (Continued) Maximum Quantity [1] in Largest Container Material Toxicity Limit (IDLH) [2] (lbs) Potassium hydroxide None established 99,999* Propionaldehyde 500 mg/m3 -TEEL [4] 600,000 Propylene Asphyxiant 740,000 Propylene glycol None established 999,999* Sand (silica dust) 30 mg/m3 -PEL [5] 99,999* Sodium Hydroxide Solution None established 999,999* Sulfolane None established 99,999* Sulfuric Acid 15 mg/m3 999,999* Lubricating Oil None established 99,999* Triphenylphosphine None established 9,999* Vanadium Pentaoxide 35 mg V/m3 9,999* Zinc Oxide 500 mg/m3 10,000* UCON LB-625 Polyalkylene Glycol None established 99,999* Vinyl Acetate 500 ppm [6] 3,700,000 Gulfstream Terminal and Marketing LLC Gasoline 300 ppm -TWA [3] 20,000 barrels Diesel Oil None established 20,000 barrels GulfMark Energy Petroleum Crude Oil None established 25,000 barrels Source - References 2.2S-32, 2.2S-36, 2.2S-37, 2.2S-39, 2.2S-40, 2.2S-43 through 2.2S-46, 2.2S-48, 2.2S-52, 2.2S-56, 2.2S-57, 2.2S-59, 2.2S-60, 2.2S-66, and 2.2S-67.
[1]Actual amount of compound in these cases, is the maximum of the reported range on the SARA Title III, Tier II report. This range envelopes an order of magnitude and represents the greatest amount present at the facility during the reporting period. (denoted by *). [2]Immediately Dangerous to Life or Health (IDLH) [3]Threshold Limit Value/ Time-Weighted Average (TLV-TWA) [4]Temporary Emergency Exposure Limit (TEEL) [5]Permissible Exposure Limit (PEL) [6]Emergency Response Planning Guideline (ERPG)
Nearby Industrial, Transportation, and Military Facilities 2.2S-37 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.2S-4 STP 3 & 4 Pipeline Information Summary Distance Between Pipeline Pipeline Operating Depth of Isolation Operator Product Diameter Age Pressure Burial Valves
Dow Pipeline Natural Gas 12.75 inches 1940 471 psig 3 to 10 feet 10 miles Company Transmission
Dow Pipeline Natural Gas 16 inches 1954 760 psig 3 to 10 feet 10 miles Company Transmission
Houston Natural Gas 8.63 inches 1964 575 psig 2 to 3 feet 7-8 miles Pipeline Transmission Company, L.P. Penn Virginia Oil Natural Gas 4.5 inches N/A N/A N/A N/A & Gas, L.P. Transmission
Texas Eastern Natural Gas 30 inches N/A N/A N/A N/A Transmission, Transmission L.P.
Enterprise Natural Gas 8.63 inches 1969 750 psig 37 inches N/A Products Transmission Operating, L.P.
Seadrift Pipeline Nitrogen 4.5 inches 1962 1494 psig 3 to 10 feet N/A Corporation
OXEA Propylene 6.63 inches 1977 875 psig 38 to 40 inches varies Corporation
OXEA Oxygen 12.75 inches N/A 875 psig 38 to 40 inches N/A Corporation/ Air Liquide
OXEA Nitrogen 10.75 inches N/A 875 psig 38 to 40 inches N/A Corporation/ Air Liquide
OXEA Ethylene 10.75 inches 1982 1000-1300 4 to 6 feet N/A Corporation/ psig Equistar
Acock/Anaqua Natural Gas 4.5 inches N/A N/A N/A N/A Operating Co., Gathering L.P.
Houston Natural Gas 4.5 inches N/A N/A N/A N/A Pipeline Gathering Company, L.P.
Kinder Morgan Natural Gas 16 inches N/A N/A N/A N/A Tejas Pipeline, Gathering L.P.
Santos USA, Natural Gas 4.5 inches N/A N/A N/A N/A Corp. Gathering
Source - References 2.2S-10 through 2.2S-21, and Reference 2.2S-62
2.2S-38 Nearby Industrial, Transportation, and Military Facilities Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.2S-5 Hazardous Chemical Waterway Freight, Colorado River Total Quantity Material Toxicity Limit (IDLH) [1] (short tons) Crude Petroleum None established 56,000 Residual Fuel Oil None established 1,000 Alcohols 1400 ppm (Butanol); 1600 ppm (Iso-Butanol) 127,000 Carboxylic Acids 50 ppm (Acetic Acid); 1700 ppm (Butyl Acetate); 500 317,000 ppm (Vinyl Acetate) [2] Source: References 2.2S-9, 2.2S-37, 2.2S-48, and 2.2S-57
[1] Immediately Dangerous to Life or Health [2] Emergency Response Planning Guideline
Nearby Industrial, Transportation, and Military Facilities 2.2S-39 Rev. 12
STP 3 & 4 Final Safety Analysis Report No further analysis analysis further No required-low vapor vapor required-low pressure [1] required required- low vapor low vapor required- pressure [1] Flammability Analysis Explosion Analysis Flammability Analysis Explosion Analysis required required- low vapor low vapor required- pressure [1] required No further analysis mm Hg analysis No further 159.599 @ 80°F psi Analysis Toxicity Not Not available N/A-solid 0.001 0.100 psi @ 100°F psi 0.100 analysis No further 23.58 psi @ 100°F psi 23.58 Analysis Toxicity one listed None listed None e listed None listed None analysis No further ble listed None Not flammable listed None Not flammable listed None Hg 0.17 @ 68°Fmm analysis No further Not flammableNot listed None Table 2.2S-6 Onsite Chemical Storage - Disposition Storage Chemical Onsite 2.2S-6 Table as 3 3 (IDLH) Flammability Hazard? Explosion Pressure Vapor Disposition Toxicity Limit Toxicity 15,000 ppm Not flammable None listed 2000 ppm 2000 Triphenyl PhosphateTriphenyl 40,000 ppm40,000 flammable Not listed None atm >1 Analysis Toxicity None established Not flammable N Material Fyrquel EHC fluidFyrquel mg/m 1000 Freon-12 Freon-12 (Dichlorodifluoromethane) Freon-11 Freon-11 (Trichlorofluoromethane) Number 2 Diesel Fuel 2 Diesel Number established None 1.3%-6.0% Hydrazine ppm 50 4.7%-100% may explode Vapor @ 100°F psi 0.567 Analysis Toxicity Gasoline 1301 Halon (Trifluorobromomethane) [2] TWA ppm- 300 1.4%-7.4% may explode Vapor mm Hg @ 292 81.4°F Analysis Toxicity 98% Sulfuric Acid 15 mg/m Sodium BromideSodium established None flammabl Not Boric Acid Hydroxide Sodium 50% established None flamma Not
2.2S-40 Nearby Industrial, Transportation, and Military Facilities Rev. 12
STP 3 & 4 Final Safety Analysis Report rence rence s to people s to people re not very asphyxiant Toxicity-consider as as Toxicity-consider asphyxiant asphyxiant Flammability Analysis Explosion Analysis vapor required-low pressure [1] , Monoethanolamine (Reference (Reference , Monoethanolamine 760 mm Hg @ -196°C Hg @ mm 760 as Toxicity-consider 294°F with vapor pressures this low a listed Not available Analysis Toxicity 8), toxicity limit for Fyrquel EHC as Triphenyl Phosphate (Refe Phosphate EHC toxicity limit 8), Fyrquel as Triphenyl for , Halon 1301 (Reference 2.2S-39) (Reference 1301 , Halon ence 2.2S-37), except for Sodium Bromide (Reference 2.2S-52), 2.2S-52), (Reference Bromide Sodium except for 2.2S-37), ence to heat were not considered. Chemicals considered. not were Table 2.2S-6 Onsite Chemical Storage - Disposition (Continued) Disposition - Storage Chemical Onsite 2.2S-6 Table (IDLH) Flammability Hazard? Explosion Pressure Vapor Disposition Toxicity Limit Toxicity 10 ppm chlorine ppm for 10 Not flammable None Sulfuric Acid (Reference 2.2S-39), Fyrquel EHC (Reference 2.2S-3 2.2S-39), vapor pressure value for Gasoline (Reference 2.2S-54) (Reference Gasoline for value pressure vapor 2.2S-39), 2.2S-39), Liquid Nitrogen (Reference 2.2S-40). (Reference Nitrogen Liquid 2.2S-39), Chemical information was obtained from the CHRIS manual (Refer the CHRIS manual from was obtained information Chemical Material r the atmosphere fast enough to reach concentrations hazardou concentrations to reach fast enough atmosphere r the ente chemicals cannot conditions, normal is, under That volatile. hazard. dispersion an air to be considered not are therefore, and, [1] 0.193 psi, torr, than 10 less pressures Chemicals with vapor Note: [2] Average (TWA) Time-Weighted Liquid NitrogenLiquid Asphyxiant Negligible if exposed listed, None HydrogenMonoethanolamine Asphyxiant ppm 30 Nitrogen 4.0%-75% 3.0%-23.5% Asphyxiant may explode Vapor @ -418°F 29.030 listed None flammable Not as Toxicity-consider 0.4 mm Hg listed None analysis No further @ - 65.820 psi 12.5% Sodium Hypochlorite
Nearby Industrial, Transportation, and Military Facilities 2.2S-41 Rev. 12
STP 3 & 4 Final Safety Analysis Report Flammability Analysis Analysis Explosion Flammability Analysis Analysis Explosion Flammability Analysis Analysis Explosion required- low vapor [1] pressure Flammability Analysis Analysis Explosion Flammability Analysis Analysis Explosion Flammability Analysis Analysis Explosion ode @ 100°F 7.516 psi Analysis Toxicity plode @ 100°F 0.597 psi Analysis Toxicity plosion Hazard?plosion Pressure Vapor Disposition Vapor may ex may Vapor Vapor may explode may Vapor @ 100°F 0.657 psi Analysis Toxicity Vapor may expl may Vapor Vapor may explode may Vapor @ 310 mmHG 38°C Analysis Toxicity Vapor may explode may Vapor 0.1mm Hg @ 20°C analysis No further Vapor may explode may Vapor @ 100°F psi 27.660 Analysis Toxicity GulfMark Energy OXEA Corporation 4%-19.9% 4%-19.9% 2.6%-12.8% 4%-60% )-TEEL [3])-TEEL LEL 0.9% 3 2500 ppm 2500 30 ppm TLV-TWA [6] TLV-TWA ppm 30 Flammable None establishedNone Flammable Table 2.2S-7 Offsite Chemicals, Disposition - OXEA Corporation, Gulfstream Terminal and Marketing LLC, and LLC, and Marketing and Terminal - OXEA Corporation, Gulfstream Disposition 2.2S-7 Offsite Chemicals, Table Material Limit (IDLH) Toxicity Flammability Ex 2-Hexene 2-Methyl Hexanoic Acid 1-Hexene1-Octene ppm TEEL [3] 30 LEL 1.2% 250 (mg/m explode may Vapor @ 100°F 5.990 psi Analysis Toxicity Acetaldehyde ppm 2000 Acetic Acid ppm 50 Acetone
2.2S-42 Nearby Industrial, Transportation, and Military Facilities Rev. 12
STP 3 & 4 Final Safety Analysis Report required- low vapor [1] pressure required- low vapor [1] pressure required- low vapor [1] pressure analysis No further asphyxiant asphyxiant Flammability Analysis Flammability Analysis Analysis Explosion Flammability Analysis Analysis Explosion required required- low vapor [1] pressure Toxicity Analysis Toxicity 907.299 psi@ 75°F psi@ 907.299 as Toxicity-consider 12 mm Hg Not available-solidNot analysis No further Not available-solid analysis No further Not available-solid analysis No further 49.090 psi @ 292°F psi 49.090 as Toxicity-consider Not available-solid analysis No further Not available listed r may exploder may @ 100°F 0.415 psi Analysis Toxicity plosion Hazard?plosion Pressure Vapor Disposition Vapo explode may Vapor @100°F 0.567 psi Analysis Toxicity None listed None OXEA Corporation GulfMark Energy (Continued) GulfMark Energy mable listed None 4.7%-100% Not FlammableNot Listed None flammableNot flammableNot listed None listed None Not flammableNot None 12-75% 3 3 3 50 ppm 50 None establishedNone flammable Not listed None Table 2.2S-7 Offsite Chemicals, Disposition - OXEA Corporation, Gulfstream Terminal and Marketing LLC, and LLC, and Marketing and Terminal - OXEA Corporation, Gulfstream Disposition 2.2S-7 Offsite Chemicals, Table Material Limit (IDLH) Toxicity Flammability Ex Zinc OxideCatalyst 500 mg/m DioxideCarbon ppm 40,000 Nickel Catalystmg/m 10 Cyclohexylamine -TEEL [3] ppm 30 1.5%-9.4% MonoxideCarbon ppm 1200 Hydrazine 2-(2-Butoxyethoxy) established None flammable Not listed None Sodium Hypochlorite Sodium chlorine for ppm 10 Aluminum Oxide Catalyst flam Not Iron Oxide Catalyst 2500 mg/m
Nearby Industrial, Transportation, and Military Facilities 2.2S-43 Rev. 12
STP 3 & 4 Final Safety Analysis Report required required- low vapor [1] pressure required- low vapor [1] pressure required- low vapor [1] pressure required- low vapor [1] pressure required- low vapor [1] pressure Flammability Analysis Analysis Explosion required- low vapor [1] pressure required- low vapor [1] pressure .001 psi @ 110°F.001 psi No further analysis 0.100 psi @ 100°F 0.100 psi analysis No further Not available-solidNot analysis No further Not available-solid analysis No further 0 Not available-solid analysis No further Not available-solid analysis No further Not available-solid analysis No further plosion Hazard?plosion Pressure Vapor Disposition Vapor may explode may Vapor @ 100°F psi 15.090 Analysis Toxicity None listed None Vapor may explode may Vapor @ 100°F 0.124 psi analysis No further OXEA Corporation GulfMark Energy (Continued) GulfMark Energy Not flammableNot flammableNot listed None flammableNot listed None listed None 1.1%-5.4% 0.9%-6.0% 3 3 -TLV [6]-TLV flammable Not listed None 3 3 None establishedNone vol. 1.3%-6.0% listed None 3000 mg/m 3000 1000 ppm 1000 establishedNone flammable Not listed None Table 2.2S-7 Offsite Chemicals, Disposition - OXEA Corporation, Gulfstream Terminal and Marketing LLC, and LLC, and Marketing and Terminal - OXEA Corporation, Gulfstream Disposition 2.2S-7 Offsite Chemicals, Table Material Limit (IDLH) Toxicity Flammability Ex Silver Catalystmg/m 10 Aluminum Silicatemg/m 10 Diesel Diatomaceous EarthDiatomaceous mg/m 3000 Silica Diisopropanolamine established None Dimethyl SulfideDimethyl [3] ppm -TEEL 2000 2.2%-19.7% Drewfloc 2449 2449 (33% Drewfloc petroleum distillate) 2625B Drewsperse Antifoulant (Potassium Hydroxide)
2.2S-44 Nearby Industrial, Transportation, and Military Facilities Rev. 12
STP 3 & 4 Final Safety Analysis Report required- low vapor [1] pressure required- low vapor [1] pressure required- low vapor [1] pressure Flammability Analysis Analysis Explosion Flammability Analysis Analysis Explosion Flammability Analysis Analysis Explosion required- low vapor [1] pressure required- low vapor [1] pressure 0.019 psi @ 161°F 0.019 psi analysis No further Not available-solid analysis No further Not available-solid analysis No further Not available-solid analysis No further plode @ 100°F 3.186 psi Analysis Toxicity listed @ 100°F 0.005 psi analysis No further plosion Hazard?plosion Pressure Vapor Disposition ne listed ne listed Vapor may explode may Vapor Hg @ 81.4°F 292 mm Analysis Toxicity Vapor may explode may Vapor @ 100°F psi 65.099 Toxicity OXEA Corporation GulfMark Energy (Continued) GulfMark Energy Not flammableNot listed None 3 -TWA [6]-TWA flammable Not listed None 3 100 mg/m Table 2.2S-7 Offsite Chemicals, Disposition - OXEA Corporation, Gulfstream Terminal and Marketing LLC, and LLC, and Marketing and Terminal - OXEA Corporation, Gulfstream Disposition 2.2S-7 Offsite Chemicals, Table Material Limit (IDLH) Toxicity Flammability Ex G55/G65 Catalyst Catalyst G55/G65 established None Calcium Carbonate flammable Not mg/m 10 No Gasoline [6]Gasoline [6] -TWA ppm 300 1.4%-7.4% Ethyl Acetate ppm 2000 Ethylene GlycolEthylene 2.2%-9.0% 15,000 ppm -TEEL [3] established None 2.75%-28.6% LEL 3.2% ex may Vapor None Hexanoic AcidHexanoic established None flammable Not No G-132 D Catalyst G-132 D Catalyst (copper oxide catalyst)
Nearby Industrial, Transportation, and Military Facilities 2.2S-45 Rev. 12
STP 3 & 4 Final Safety Analysis Report required- low vapor [1] pressure asphyxiant Flammability Analysis Analysis Explosion required- low vapor [1] pressure Flammability Analysis Analysis Explosion required- low vapor [1] pressure Flammability Analysis Analysis Explosion Flammability Analysis Analysis Explosion 0.001 mm Hg Hg 0.001 mm analysis No further Not Available-solid analysis No further Not available-solid analysis No further ode @ 29.030 -418°F as Toxicity-consider plode @ 100°F 0.513 psi Analysis Toxicity y explode @ 100°F 0.664 psi Analysis Toxicity r may exploder may @ 100°F 5.666 psi Analysis Toxicity plosion Hazard?plosion Pressure Vapor Disposition Vapor may ex may Vapor Vapo Vapor ma Vapor OXEA Corporation GulfMark Energy (Continued) GulfMark Energy 1.6%-10.9% 2.4%-10.5% Not flammableNot listed None flammableNot listed None flammableNot listed None 3 3 3 1600 ppm 1600 Table 2.2S-7 Offsite Chemicals, Disposition - OXEA Corporation, Gulfstream Terminal and Marketing LLC, and LLC, and Marketing and Terminal - OXEA Corporation, Gulfstream Disposition 2.2S-7 Offsite Chemicals, Table Material Limit (IDLH) Toxicity Flammability Ex Hydrogen AsphyxiantHydroquinone mg/m 50 4.0%-75% expl may Vapor Isobutyraldehyde [3] ppm -TEEL 1500 2.0%-10% Calcium Oxidemg/m 25 Isobutanol Isobutyl AcetateIsobutyl ppm 1300 Sulfuric AcidSulfuric 15 mg/m
2.2S-46 Nearby Industrial, Transportation, and Military Facilities Rev. 12
STP 3 & 4 Final Safety Analysis Report asphyxiant Flammability Analysis Analysis Explosion required- low vapor [1] pressure Flammability Analysis Analysis Explosion Flammability Analysis Analysis Explosion Flammability Analysis Analysis Explosion required- low vapor [1] pressure required- low vapor [1] pressure plode @ -240°F psi 31.920 as Toxicity-consider explode @ 100°F 0.489 psi Analysis Toxicity plosion Hazard?plosion Pressure Vapor Disposition ne listed @ 180°F 0.028 psi analysis No further OXEA Corporation GulfMark Energy (Continued) GulfMark Energy None establishedNone flammable Not listed None < 1 mm Hg @ 20°C Analysis No further Table 2.2S-7 Offsite Chemicals, Disposition - OXEA Corporation, Gulfstream Terminal and Marketing LLC, and LLC, and Marketing and Terminal - OXEA Corporation, Gulfstream Disposition 2.2S-7 Offsite Chemicals, Table Material Limit (IDLH) Toxicity Flammability Ex Methane [3] ppm -TEEL 25,000 Sulfonic Methane 5.0%-15%Acid Monoethanolamine ppm 30 ex may Vapor N-Butanol 3.0%-23.5% ppm 1400 AcetateN-Butyl ppm 1700 listed None N-Butyraldehyde 1.45%-11.25% [3] ppm -TEEL 2000 1.7%-7.6% 2.5%-10.6% N-Heptanal listed None 0.4 mm Hg explode may Vapor AcidN-Heptanoic may Vapor established None established None 5.5 mm Hg @25°C analysis No further @ 100F 5.670 psi 0.78%-15.25% Analysis Toxicity flammable Not Analysis Toxicity listed None No 3.52 mm Hg @ 25°C analysis No further
Nearby Industrial, Transportation, and Military Facilities 2.2S-47 Rev. 12
STP 3 & 4 Final Safety Analysis Report required- low vapor [1] pressure required- low vapor [1] pressure Flammability Analysis Analysis Explosion Flammability Analysis Analysis Explosion asphyxiant required required required- low vapor [1] pressure required required 0.03 mm 0.03 mm Hg @ 20°C analysis No further 65.820 psi @ -294°F psi 65.820 as Toxicity-consider Not available-solid analysis No further Not available-solid analysis No further y explode @ 100°F 1.232 psi Analysis Toxicity y explode @ 100°F 0.732 psi Analysis Toxicity plosion Hazard?plosion Pressure Vapor Disposition ne listed OXEA Corporation GulfMark Energy (Continued) GulfMark Energy Not flammableNot flammableNot may explode Dust 0.1 Hg @ 77°Fmm listed None analysis No further 3 3 None establishedNone flammable Not listed None Table 2.2S-7 Offsite Chemicals, Disposition - OXEA Corporation, Gulfstream Terminal and Marketing LLC, and LLC, and Marketing and Terminal - OXEA Corporation, Gulfstream Disposition 2.2S-7 Offsite Chemicals, Table Material Limit (IDLH) Toxicity Flammability Ex Phosphoric Acid 1000 mg/m N-Nonanal AcetateN-Propyl established None ppm 1700 0.59%-6.54% AlcoholN-Propyl ppm 800 2.0%-8.0% listed None Nitrogen AcidNonanoic ma Vapor 2.1%-13.5% 0.2 mm Hg @ 20°COxygen Asphyxiant established None analysis No further Parabenzoquinone ma Vapor flammable Not 100 mg/m flammable Not established None listed None flammable Not listed None listed None 1 mm Hg @ 108°C analysis No further @ -280°F psi 36.260 analysis No further Potassium AcetatePotassium established None Potassium Hydroxide flammable Not No
2.2S-48 Nearby Industrial, Transportation, and Military Facilities Rev. 12
STP 3 & 4 Final Safety Analysis Report required required- low vapor [1] pressure required- low vapor [1] pressure Flammability Analysis Analysis Explosion required- low vapor [1] pressure required required- low vapor [1] pressure asphyxiant Flammability Analysis Analysis Explosion required- low vapor [1] pressure 10 mm Hg @ 3150°F analysis No further 13mm Hg @ 140°F analysis No further 0.005 psi @ 100°F 0.005 psi analysis No further Not available-solid analysis No further 0.038 psi @ 220°F 0.038 psi analysis No further 0.100 psi @ 100°F 0.100 psi analysis No further ode -40°F psi@ 20.600 as Toxicity-consider listed listed plosion Hazard?plosion Pressure Vapor Disposition ne listed Vapor may expl may Vapor Vapor may explode may Vapor 100°F psi@ 10.130 Analysis Toxicity None None None None OXEA Corporation GulfMark Energy (Continued) GulfMark Energy 2.0%-11.0% Not flammableNot listed None Not available analysis No further (dust or or (dust ) -TEEL [3]) 2.6%-16.1% 3 3 -PEL -PEL [5] flammable Not listed None 3 Asphyxiant fume) 35 mg V/m None establishedNone flammable Not listed None None establishedNone flammable Not listed None Table 2.2S-7 Offsite Chemicals, Disposition - OXEA Corporation, Gulfstream Terminal and Marketing LLC, and LLC, and Marketing and Terminal - OXEA Corporation, Gulfstream Disposition 2.2S-7 Offsite Chemicals, Table Material Limit (IDLH) Toxicity Flammability Ex Propionaldehyde (mg/m 500 Vanadium Vanadium Pentaoxide Sodium Hydroxide Hydroxide Sodium Solution Propylene Tripenylphosphine established None listed Not Sulfolane OilLubricating established None flammable Not No Propylene GlycolPropylene established None Sand (silica dust) 2.6%-12.5% mg/m 30
Nearby Industrial, Transportation, and Military Facilities 2.2S-49 Rev. 12
STP 3 & 4 Final Safety Analysis Report required- low vapor [1] pressure required- low vapor [1] pressure Flammability Analysis Analysis Explosion Flammability Analysis Analysis Explosion required- low vapor [1] pressure 0.100 psi @ 100°F 0.100 psi analysis No further <0.01 mm Hg @ <0.01 20°C analysis No further Not available-solid analysis No further r may exploder may @ 100°F 3.977 psi Analysis Toxicity plosion Hazard?plosion Pressure Vapor Disposition Vapor may explode may Vapor Hg @ 81.4°F 292 mm Analysis Toxicity Vapo None listed None OXEA Corporation GulfMark Energy (Continued) GulfMark Energy Gulfstream Terminal and Marketing LLC and Marketing Terminal Gulfstream Not flammableNot listed None 3 None establishedNone vol. 1.3%-6.0% listed None 500 mg/m 500 None establishedNone listed Not Table 2.2S-7 Offsite Chemicals, Disposition - OXEA Corporation, Gulfstream Terminal and Marketing LLC, and LLC, and Marketing and Terminal - OXEA Corporation, Gulfstream Disposition 2.2S-7 Offsite Chemicals, Table Material Limit (IDLH) Toxicity Flammability Ex Gasoline [4]Gasoline [6] -TWA ppm 300 1.4%-7.4% Zinc Oxide UCON LB-625 Polyalkylene Glycol AcetateVinyl -ERPG [7]ppm 500 2.6%-13.4% Diesel Oil
2.2S-50 Nearby Industrial, Transportation, and Military Facilities Rev. 12
STP 3 & 4 Final Safety Analysis Report e nanal nanal .2S- 7); and and 7); DLH rth and, and, silver nce 2.2S-48). barge on the the on barge & 4. & 4. not very volatile. Flammability Analysis Analysis Explosion ort of gasoline by ort of gasoline sulfonic acid (Reference 2.2S-6 mmability of Cyclohexylamine, I ne, Sand, and Diatomaceous Ea imity, 16,276 feet, to STP 3 feet, 16,276 imity, 7); N-Heptanal (Reference 2.2S-44); N-No 2.2S-44); (Reference N-Heptanal 7); unded by the transp aluminum oxide, iron oxide, oxide, zinc oxide, iron oxide, aluminum 0.100 psi @ 100°F0.100 psi Analysis Toxicity essure of Phosphoric Acid, fla Acetate (Reference 2.2S-52); Polyalkylene Glycol (Reference 2 ce 2.2S-37); 2-Hexene (Reference 2.2S-40); 2-Hexene assumed sam assumed 2-Hexene 2.2S-40); (Reference 2-Hexene ce 2.2S-37); plosion Hazard?plosion Pressure Vapor Disposition id (Reference 2.2S-66); methane e, 1,680,000 gallons and its prox and its gallons 1,680,000 e, re not considered. Chemicals with vapor pressures this low are pressures with vapor Chemicals not considered. re GulfMark Energy GulfMark GulfMark Energy (Continued) GulfMark Energy ence 2.2S-43); vapor pr ence ce 2.2S-39); sodium hydroxide solution, Tripenylphosphi cannot enter the atmosphere fast enough to reach concentrations hazardous to people hazardous concentrations reach to enough fast the atmosphere enter cannot 2.2S-59); 2-Methyl Hexanoic Ac2.2S-59); 2-Methyl Hexanoic rporation and Gulfstream Terminal and Marketing LLC is bo rporation and Gulfstream Terminal oxyethoxy) (Refer onse Planning Guideline (ERPG) Guideline Planning onse ethylene, isobutyraldehyde, methane, N-butyraldehyde, propionaldehyde, and Vinyl Acetate (Refere Acetate Vinyl and propionaldehyde, N-butyraldehyde, methane, isobutyraldehyde, toxicity of dimethlyl sulfide, ethylene, catalyst, silica, and copper oxide (Referen silica, and copper catalyst, 2.2S-5 (Reference N-Butanol 2.2S-56); (Ref erence 2.2S-36); Isobutyraldehyde (Reference Potassium 2.2S-45); Acid (Reference 2.2S-57); Nonanoic (Reference 46); Aluminum Silicate (Reference IDLH as 1-Hexene; 2-(2-But IDLH as catalyst, nickel Parabenzoquinone, Acid, Sulfuric Monoethanolamine, of Chlorine, value Table 2.2S-7 Offsite Chemicals, Disposition - OXEA Corporation, Gulfstream Terminal and Marketing LLC, and LLC, and Marketing and Terminal - OXEA Corporation, Gulfstream Disposition 2.2S-7 Offsite Chemicals, Table Chemical information was obtained from the CHRIS manual (Referen the CHRIS manual from was obtained information Chemical Colorado River due to the quantity of gasoline carried on on the barg carried gasoline of quantity to the River due Colorado That is, under normal conditions, conditions, chemicals normal is, under That hazard. air dispertion to be an considered not are therefore, Material Limit (IDLH) Toxicity Flammability Ex Note: [5]Permissible Exposure Limit (PEL) Limit Exposure [5]Permissible Weighted Average (TLV-TWA) [6]Threshold Limit Value/Time [7]Emergency Resp [2]This is bounded by the onsite storage of liquid nitrogen. of liquid onsite storage by the is bounded [2]This (TEEL) Limit Exposure Emergency [3]Temporary stored at OXEA [4]The gasoline Co [1]Chemicals with vapor pressure less than 10 torr, 0.193 psi, we psi, 0.193 10 torr, than less pressure with vapor [1]Chemicals Crude PetroleumCrude Established None flammable Not C ombustible
Nearby Industrial, Transportation, and Military Facilities 2.2S-51 Rev. 12
STP 3 & 4 Final Safety Analysis Report Flammability Analysis Explosion Analysis Flammability Analysis Explosion Analysis Flammability Analysis Explosion Analysis required- low vapor low vapor required- pressure [1] Flammability Analysis Explosion Analysis Flammability Analysis Explosion Analysis required- low vapor low vapor required- pressure [1] psi @ 100°Fpsi analysis No further ode @ 100°F 0.597 psi Analysis Toxicity explode @ 100°F 3.977 psi Analysis Toxicity Flammability ? Hazard Explosion Pressure Vapor Disposition tablished 1%-5% None listed 0.100 Table 2.2S-8 Hazardous Materials, Navigable Waterway Transportation - Disposition - Transportation Waterway Navigable Materials, Hazardous 2.2S-8 Table Material(IDLH) Limit Toxicity N-Butyl AcetateN-Butyl ppm 1700 AcetateVinyl [2] ppm 500 1.7%-7.6% may explode Vapor 2.6%-13.4% @ 100°F psi 0.489 may Vapor Analysis Toxicity N-ButanolIsobutanol ppm 1400 Acetic Acid ppm 1600 1.45%-11.25% ppm 50 listed None 1.6%-10.9% 5.5 mm Hg @ 25°C may explode Vapor Analysis Toxicity @ 100°F psi 0.513 4%-19.9% Analysis Toxicity may expl Vapor Residual Fuel Oil (#6) Fuel Residual es None Crude PetroleumCrude established None Not flammable listed None @ 100°F psi 0.100 analysis No further
2.2S-52 Nearby Industrial, Transportation, and Military Facilities Rev. 12
STP 3 & 4 Final Safety Analysis Report e s to s to exposed re not very Flammability Analysis Explosion Analysis ee of the American Industrial Industrial American of the ee nearly all individuals could be be could all individuals nearly with vapor pressures this low a st enough to reach concentrations hazardou concentrations to reach st enough developed by the ERPG committ by the developed elines, to anticipate human adverse health effects by caused effects health adverse human to anticipate elines, below that which it is believed ence 2.2S-37), except for N-Butanol (Reference 2.2S-57), vapor vapor 2.2S-57), (Reference N-Butanol except for 2.2S-37), ence lines with one common denominator: a 1-hour contact duration. Th duration. contact a 1-hour denominator: common lines with one were not considered. Chemicals considered. not were vinyl acetate (References 2.2S-44 and 2.2S-48). Flammability ? Hazard Explosion Pressure Vapor Disposition , chemicals cannot enter the atmosphere fa atmosphere the enter cannot , chemicals Table 2.2S-8 Hazardous Materials, Navigable Waterway Transportation - Disposition (Continued) - Disposition Transportation Waterway Navigable Materials, Hazardous 2.2S-8 Table pressure of gasoline (Reference 2.2S-54), and and 2.2S-54), (Reference of gasoline pressure selected ERPG is defined as the maximum airborne concentration Hygiene Association. The ERPGs were developed as planning guid guide three-tiered The ERPGs are to toxic chemicals. exposure volatile. That is, under conditions normal is, under volatile. That hazard. dispersion an air to be ed consider not are therefore, and, people for up to 1 hour without experiencing or developing life-threatening health effects. Chemical information was obtained from the CHRIS manual (Refer the CHRIS manual from was obtained information Chemical Material(IDLH) Limit Toxicity [2]ERPGs were (ERPGs)--The Guidelines Planning Response Emergency [1] 0.193 psi, torr, than 10 less pressures Chemicals with vapor Note: [3] Weighted Average (TWA) Time Gasoline [3] TWA ppm- 300 1.4%-7.4% may explode Vapor mm Hg @ 292 81.4°F Analysis Toxicity
Nearby Industrial, Transportation, and Military Facilities 2.2S-53 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.2S-9 Design-Basis Events - Explosions Distance for Distance Explosion to to Nearest have less than 1 Heat of Safety- psi of Peak Pollutant Combustion Related Incident Source Evaluated Quantity (Btu/lb) Structure Pressure FM 521 Gasoline 9,000 gal 18,720 Btu/lb 2700 ft 266 ft Pipeline: Dow Natural Gas 2,218,242 lbs 21,517 Btu/lb 10,000 ft 7,577 ft Pipeline (entire mass of a Company 10 minute release) Navigable n-Butanol 380,000 gal 14,230 Btu/lb 15,974 ft 896 ft Waterway Isobutanol 380,000 gal 14,220 Btu/lb 888 ft (Colorado River) Acetic Acid 500,000 gal 5,645 Btu/lb 814 ft n-Butyl Acetate 380,000 gal 13,130 Btu/lb 885 ft Vinyl Acetate 380,000 gal 9,754 Btu/lb 880 ft Gasoline 40,000 BBLs or 18,720 Btu/lb 1,517 ft 1,680,000 gal Onsite (Includes Gasoline (12,000 12,000 gal 18,720 Btu/lb 1,771 ft 296 ft STP 1 & 2) gallon above ground storage tank) Hydrazine 1,260 lbs 8,345 Btu/lb 2,518 ft 86 ft Hydrogen 100,200 ft3 50,080 Btu/lb 1,563 ft 1,048 ft
2.2S-54 Nearby Industrial, Transportation, and Military Facilities Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.2S-9 Design-Basis Events - Explosions (Continued) Distance for Distance Explosion to to Nearest have less than 1 Heat of Safety- psi of Peak Pollutant Combustion Related Incident Source Evaluated Quantity (Btu/lb) Structure Pressure Offsite (OXEA 1-Hexene 1,265,000 lbs 19,134 Btu/lb 22,841 ft 734 ft Corp.) 1-Octene 2,010,000 lbs 19,170 Btu/lb 766 ft 2-Hexene 3,861 lbs 19,134 Btu/lb 108 ft Acetaldehyde 866,295 lbs 10,600 Btu/lb 835 ft Acetic Acid 9,999,999 lbs 5,645 Btu/lb 1,072 ft Acetone 4,400 lbs. 12,250 Btu/lb 99 ft Cyclohexylamine 4,000 lbs 18,000 Btu/lb 114 ft Hydrazine 4,000 lbs 8,345 Btu/lb 126 ft Dimethyl Sulfide 10,000 lbs 13,200 Btu/lb 154 ft Ethyl Acetate 21,800 lbs 10,110 Btu/lb 154 ft 1-Hexene 1,265,000 lbs 19,134 Btu/lb 734 ft Ethylene 470,000 lbs 20,290 Btu/lb 7,575 ft Hydrogen 58,512 lbs 50,080 Btu/lb 5,111 ft Isobutanol 3,455,333 lbs 14,220 Btu/lb 984 ft Isobutyl Acetate 9,999,999 lbs 13,000 Btu/lb 1,509 ft Isobutyraldehyde 999,999 lbs 13,850 Btu/lb 622 ft Methane 47,000 lbs 21,517 Btu/lb 3,586 ft n-Butanol 16,921,268 lbs. 14,230 Btu/lb 1,681 ft n-Butyl Acetate 9,999,999 lbs. 13,130 Btu/lb 1,358 ft n-Butyraldehyde 3,300,000 lbs. 15,210 Btu/lb 969 ft n-Propyl Acetate 9,999,999 lbs 9, 420 Btu/lb 1,178 ft Ethylene 470,000 lbs 20,290 Btu/lb 7,575 ft n-Propyl Alcohol 9,999,999 lbs 13,130 Btu/lb 1,365 ft Propionaldehyde 600,000 lbs 12,470 Btu/lb 548 ft Propylene 740,000 lbs 19,692 Btu/lb 8,724 ft Vinyl Acetate 3,700,000 lbs 9,754 Btu/lb 948 ft Offsite Crude Petroleum 1,050,000 gal 18,252 Btu/lb 24,244 ft 1,124 ft (GulfMark)
Nearby Industrial, Transportation, and Military Facilities 2.2S-55 Rev. 12
STP 3 & 4 Final Safety Analysis Report (psi) Related Structure Structure Related at Nearest Safety- Peak Overpressure overpressure overpressure overpressure Cloud Cloud for Vapor Vapor for Explosions Safe Distance Distance Safe No explosion explosion No LFL Distance to to Distance Never exceeded 492 ft492 ft 1,494 [1] Not provided UFL 41 ft ft 138 No explosion explosion No Distance to to Distance 606 ft606 ft 975 ft 1,974 No significant 4,554 ft4,554 ft 5,605 ft 8,642 Not available exceeded provided [1] 795 ft 1,812 ft 3,570 psi 0.119 Never Never 507 ft507 ft 918 ft 1,848 No significant Safety- Related Distance Distance Structure to Nearest to Nearest 2700 ft2700 ft 243 ft 408 ft 1,035 psi 0.379 1,563 ft1,563 ft1,807 ft 300 1 ft 1,362 ft 1,557 psi 0.987 1,771 ft1,771 ft 285 ft 480 ft 1,200 psi 0.537 10,000 ft Not 2,518 ft2,518 <33 ft <33 ft No explosion explosion No 15,974 ft15,974 ft 432 ft 801 ft 1,593 No significant ) 3 Pollutant EvaluatedPollutant & Quantity Monoethanolamine (15,000 gal) (15,000 Monoethanolamine Natural Gas gal) (380,000 n-Butanol Vinyl Acetate (380,000 gal) (380,000 Acetate Vinyl gal) (1,680,000 Gasoline Gasoline (12,000gallon above ground storage tank) Hydrazine (150 gal) (150 Hydrazine n-Butyl Acetate (380,000 gal) (380,000 n-Butyl Acetate Hydrogen (80,000 ft Isobutanol (380,000 gal) (380,000 Isobutanol gal) Acetic Acid (500,000 Table 2.2S-10 Design-Basis Events, Flammable Vapor Clouds (Delayed Ignition) and Vapor Cloud Explosions Vapor and Ignition) Clouds (Delayed Vapor Flammable Events, Design-Basis 2.2S-10 Table Source FM FM 521Pipeline: Dow Pipeline Company gal) (9,000 Gasoline Waterway River) (Colorado Onsite (Includes STP 1 & 2)
2.2S-56 Nearby Industrial, Transportation, and Military Facilities Rev. 12
STP 3 & 4 Final Safety Analysis Report (psi) Related Structure Structure Related at Nearest Safety- Peak Overpressure overpressure overpressure overpressure overpressure overpressure overpressure overpressure overpressure overpressure No significant significant No No significant No significant No significant No significant No significant No significant Cloud Cloud for Vapor Vapor for Explosions Safe Distance Distance Safe No explosion explosion No LFL Distance to to Distance 186 ft186 ft 537 <33 ft<33 ft 66 Never exceeded UFL Distance to to Distance 4,146 ft4,146 ft 12,672 ft 14,784 psi 0.315 159 ft159 ft 258 ft 600 180 ft180 ft 399 ft 891 Never Never 78 ft78 ft 150 ft 387 exceeded ft468 ft 843 ft 1,698 No significant exceeded exceeded ft3,651 ft 12,672 ft 14,256 psi 0.200 3,780 ft3,780 ft 7,920 ft 10,032 psi 0.186 Never Never Never <33 ft<33 ft <33 explosion No explosion No Safety- Related Distance Distance Structure to Nearest to Nearest Pollutant EvaluatedPollutant & Quantity 1-Hexene (1,265,000 lbs) (1,265,000 1-Hexene ft 22,841 ft 240 ft 423 ft 948 No significant 1-Octene (2,010,000 lbs) (2,010,000 1-Octene lbs)(3,861 2-Hexene lbs) (866,300 Acetaldehyde lbs) Acetic Acid (9,999,999 lbs) (4,000 Hydrazine ft 546 lbs) (868,000 Monoxide Carbon lbs) Dimethyl Sulfide (10,000 ft 1,059 ft 111 ft 360 lbs) (21,800 Ethyl Acetate ft 2,142 ft 201 ft 3,012 lbs) (470,000 Ethylene lbs) (58,512 Hydrogen No significant ft 5,808 ft 507 lbs) (3,455,333 Isobutanol lbs) (9,999,999 Acetate Isobutyl psi 0.161 No significant Cyclohexylamine (4,000 lbs) (4,000 Cyclohexylamine Acetone lbs) Acetone (4,400 Source Table 2.2S-10 Design-Basis Events, Flammable Vapor Clouds (Delayed Ignition) and Vapor Cloud Explosions (Continued) Cloud Explosions Vapor and Ignition) Clouds (Delayed Vapor Flammable Events, Design-Basis 2.2S-10 Table Offsite (OXEA Offsite Corp.)
Nearby Industrial, Transportation, and Military Facilities 2.2S-57 Rev. 12
STP 3 & 4 Final Safety Analysis Report (psi) Related Structure Structure Related at Nearest Safety- Peak Overpressure overpressure overpressure overpressure overpressure overpressure overpressure overpressure Cloud Cloud for Vapor Vapor for Explosions Safe Distance Distance Safe No explosion explosion No No explosion explosion No LFL Distance to to Distance Never exceeded Never exceeded 1,575 ft1,575 ft 3,138 No significant ft ft 1,560 ft 3,234 No significant UFL Distance to to Distance exceeded 909 ft909 ft 2,241 ft 4,224 No significant exceeded Safety- Related Distance Distance Structure to Nearest to Nearest Pollutant EvaluatedPollutant & Quantity n-Butyraldehyde (3,300,000 lbs) (3,300,000 n-Butyraldehyde 756 n-Butyl Acetate (9,999,999 lbs) (9,999,999 n-Butyl Acetate ft 429 ft 618 ft 1,269 No significant Methane (47,000 lbs) (47,000 Methane lbs) (16,921,268 n-Butanol ft 2,565 Never ft 4,614 ft 5,808 significant No Isobutyraldehyde (999,999 lbs) (999,999 Isobutyraldehyde ft 22,841 Hydrogen (58,512 lbs) (58,512 Hydrogen lbs) (9,999,999 Alcohol n-Propyl lbs) (600,000 Propionaldehyde lbs) (740,000 Propylene lbs) (3,700,000 Acetate Vinyl ft 396 ft 3,651 ft 822 ft 687 ft 12,672 ft 2,415 ft 1,383 ft 14,256 ft 741 ft 546 ft 4,725 psi 0.200 ft 2,694 No significant psi 0.112 ft 7,920 psi 0.238 n-Propyl Acetate (9,999,999 lbs) (9,999,999 Acetate n-Propyl ft 612 ft 966 ft 1,938 No significant n-Heptanal (325,000 lbs) (325,000 n-Heptanal Never Source Table 2.2S-10 Design-Basis Events, Flammable Vapor Clouds (Delayed Ignition) and Vapor Cloud Explosions (Continued) Cloud Explosions Vapor and Ignition) Clouds (Delayed Vapor Flammable Events, Design-Basis 2.2S-10 Table Offsite (OXEA Offsite Corp.)
2.2S-58 Nearby Industrial, Transportation, and Military Facilities Rev. 12
STP 3 & 4 Final Safety Analysis Report (psi) L, rather than than L, rather r this Related Structure Structure Related at Nearest Safety- Peak Overpressure Cloud Cloud for Vapor Vapor for Explosions Safe Distance Distance Safe rate of crude is so petroleum vapor low that a of cloud substantial is concentration reached. never intake and distances to to the LF and distances intake LFL Distance to to Distance UFL Distance to to Distance intake, intake, room control the to reaching below the toxicity limit prior ired. Further, the LFL distance was the reported distance fo distance was the reported distance the LFL ired. Further, Safety- Related ations outside the control the control room ations outside Distance Distance Structure to Nearest to Nearest Pollutant EvaluatedPollutant & Quantity Crude Petroleum (1,050,000 gal) (1,050,000 Petroleum Crude ft 24,244 evaporation The calculation as this distance is greater than the UFL. the ALOHA model. Because, the toxic concentrations had dissipated had the toxic Because, the concentrations ALOHA model. requ not was room control inside the the concentration calculating Source [1] Not provided-A calculation was performedto determine concentr Table 2.2S-10 Design-Basis Events, Flammable Vapor Clouds (Delayed Ignition) and Vapor Cloud Explosions (Continued) Cloud Explosions Vapor and Ignition) Clouds (Delayed Vapor Flammable Events, Design-Basis 2.2S-10 Table Offsite Offsite (GulfMark)
Nearby Industrial, Transportation, and Military Facilities 2.2S-59 Rev. 12
STP 3 & 4 Final Safety Analysis Report Room Room Concentration Maximum Control > 1 [3] > 1 hr >1 hr [3] >1 > 1 [3] > 1 hr 22.9 ppm >1 hr [3] >1 ppm 653 ppm 110 ppm 154 5.97 [7] 5.97 ppm 34.8 ppm Not applicable [4] Not applicable 2,205 ft 2,205 2,292 ft 2,292 ft 8,448 6,443 ft [8] ft 6,443 10,032 ft 10,032 STP 3 & 4 Distance to to Distance Control Room to IDLH Distance 2,853 ft ft15,974 2,034 ft ft 1,974 1,976 ft1,976 ft 2,388 1,755 ft 651 ft IDLH 15,000 ppm15,000 ft 1,755 ft 1,521 300 ppm TWA /500 /500 ppm TWA 300 Asphyxiant ft 1,668 [5] Not applicable ppm 1,490 ppm STEL ppm ppm STEL ppm 40,000 ppm40,000 ft 2,032 ft 522 ppm STEL ppm 300 ppm TWA /500 /500 ppm TWA 300 2,000 ppm 3 Quantity 9,000 gal 9,000 500,000 gal500,000 50 ppm 1,680,000 gal1,680,000 /500 ppm TWA 300 12,000 gal 12,000 2,917 lbs 380,000 gal380,000 ppm 1,600 9,150 lbs 9,150 55,200 lbs 55,200 80,000 ft 80,000 380,000 gal380,000 ppm 1,400 Table 2.2S-11 Design-Basis Events, Toxic Vapor Clouds Vapor Toxic Events, Design-Basis 2.2S-11 Table Chemical Freon-11 Sodium HypochloriteSodium gal 7,200 MonoethanolamineHydrazine gal 15,100 Nitrogen as Chlorine 10 ppm NitrogenLiquid ft 2,559 30 ppm gal 150 lbs 92,400 lbs 20,000 ft 177 ft 1,961 50 ppm Asphyxiant Asphyxiant ft ppm 867 0.045 ft 1,613 ft 1,613 ft 2,671 [5] Not applicable [5] Not applicable ft 843 4.31 ppm ppm 1,390 ppm 5,540 1.84 ppm Vinyl AcetateVinyl Gasoline gal 380,000 Gasoline ppm 500 n-Butyl Acetaten-Butyl gal 380,000 ppm 1,700 Freon-12 n-Butanol Halon 1301 Halon Hydrogen Isobutanol Acid Acetic Source Onsite (Includes STP 1 & 2) FM FM 521 Gasoline Waterway River) (Colorado
2.2S-60 Nearby Industrial, Transportation, and Military Facilities Rev. 12
STP 3 & 4 Final Safety Analysis Report Room Room Concentration Maximum Control > 1 [3] > 1 hr > 1 [3] > 1 hr >1 hr [3] >1 >1 hr [3] >1 >1 hr [3] >1 >1 hr [3] >1 > 1 [3] > 1 hr >1 hr [3] >1 hr [3] >1 >1 hr [3] >1 hr [3] >1 >1 hr [3] >1 > 1 hr [3] hr [3] >1 >1 hr [3] >1 >1 hr [3] >1 hr [3] >1 2.80 [7] 2.80 ppm >1 hr [3] >1 1,956 ft 1,956 6,336 ft 6,336 7,920 ft 7,920 4,563 ft 4,563 11,616 ft 11,616 1,380 ft 1,380 4,392 ft 4,392 921 ft 921 ft 1,083 ft 777 672 ft 672 1,500 ft 1,500 7,392 ft [7] ft 7,392 114 ft 114 1,377 ft 1,377 8,976 ft 8,976 399 ft 13,200 ft 13,200 3,645 ft 3,645 Not applicable [5]Not applicable > [3] 1 hr 10,660 ft [6] ft 10,660 [6] STP 3 & 4 Distance to to Distance Control Room to IDLH Distance 3 IDLH 25,000 ppm [1] ppm 25,000 30 ppm [1] 30 ppm 2,000 ppm 2,000 50 ppm 2,000 ppm 2,000 10 ppm 2,500 ppm 30 ppm Asphyxiant Quantity 9,999,999 lbs9,999,999 50 ppm 4,000 lbs 4,000 470,000 lbs470,000 ppm 15,000 47,000 lbs 47,000 4,400 lbs 16,921,268 lbs16,921,268 ppm 1,400 3,455,333 lbs3,455,333 ppm 1,600 58,512 lbs 58,512 3,861 lb 3,861 Table 2.2S-11 Design-Basis Events, Toxic Vapor Clouds (Continued) Clouds Vapor Toxic Events, Design-Basis 2.2S-11 Table Chemical Carbon DioxideCarbon lbs 868,000 ppm 40,000 n-Butanol n-Butanol n-Butyl Acetate Acetate n-Butyl lbs 9,999,999 ppm 1,700 n-Butyraldehyde n-Butyraldehyde lbs 3,300,000 ppm [1] 2,000 Isobutyraldehyde Isobutyraldehyde lbs 1,000,000 ppm [1] 1,500 Isobutanol Isobutyl Acetate lbs 9,999,999 Methane ppm 1,300 Ethylene Hydrogen Cyclohexylamine Cyclohexylamine lbs 4,000 Hydrazine HypochloriteSodium lbs 30,000 Monoxide Carbon lbs 868,000 ppm 1,200 Acetone SulfideDimethyl lbs 10,000 Acetate Ethyl lbs 21,800 Acetic Acid Acid Acetic Acetaldehyde lbs 866,300 ppm 2,000 2-Hexene 1-Hexene1-Octene lbs 1,265,000 lb 2,010,000 [1] 30 ppm mg/m 250 ft 22,841 [7] ft 7,392 [7] 1.36 ppm Source Offsite (OXEA Offsite Corp.)
Nearby Industrial, Transportation, and Military Facilities 2.2S-61 Rev. 12
STP 3 & 4 Final Safety Analysis Report ncentration ario was nd rises nd rises Room Room oncentrations oncentrations likely to change likely to as performed was was as performed Concentration Maximum Control > 1 [3] > 1 hr >1 hr [3] >1 > 1 hr [3] N/A- The evaporation evaporation The N/A- rate ofcrude petroleum is so low of cloud a vapor that substantial is concentration reached. never > 1 [3] > 1 hr 8,448 ft 8,448 21,120 ft evaporation rate of crude petroleum is so low that a vapor of substantial cloud concentration is never reached. 2,637 ft 2,637 Not applicable [5]Not applicable > [3] 1 hr Not applicable [5]Not applicable > [3] 1 hr ce to the IDLH of 5,808 ft with with a maximum co IDLH of 5,808 ft ce to the STP 3 & 4 Distance to to Distance Control Room to IDLH Distance 22,841 ft22,841 ft 2,451 24,244 ftThe N/A- 3 plume travels to a maximum horizontal distance of 10,660 ft a ft 10,660 of distance horizontal maximum a to travels plume ane as a surrogate for gasoline. The following worst-case scen worst-case following for The gasoline. a surrogate as ane trations outside the control room intake. Because, the toxic c the Because, intake. room control the trations outside IDLH that the weather conditions or other release circumstances are are circumstances release other or conditions the weather that postulated event where a meteorological sensitivity analysis w sensitivity analysis meteorological a where event postulated of crude petroleum petroleum of crude is so low that a cloud of vapor substantial is concentration reached. never Quantity s are lowered to less than IDLH than values. to less lowered s are F stability class at 3 m/s which yielded a distan at 3 m/s which yielded class F stability 740,000 lbs740,000 Asphyxiant 9,999,999 lbs9,999,999 Asphyxiant phyxiant with no associated toxicity limit. Table 2.2S-11 Design-Basis Events, Toxic Vapor Clouds (Continued) Clouds Vapor Toxic Events, Design-Basis 2.2S-11 Table se Planning Guideline (ERPG). Guideline se Planning Chemical Propionaldehyde lbs 600,000 mg/m 500 n-Propyl Alcoholn-Propyl lbs 9,999,999 ppm 800 Nitrogen Propylene Acetate Vinyl lbs 3,700,000 ppm [2] 500 Crude PetroleumCrude gal 1,050,000 rate evaporation The n-Propyl Acetate Acetate n-Propyl lbs 9,999,999 ppm 1,700 after an hour. an after vertically to 4,100 ft before concentration before ft to 4,100 vertically room. control the in concentration the highest yiel ding conditions meteorological those the upon based determinedusing the ALOHA model: scenario. postulated the during room control the in ppm 13.8 reaching had dissipated below the toxicity limit prior to reaching the control room intake, calculating the concentration inside the con trol room was not inside concentration the calculating intake, room the control to reaching toxicity prior the limit below dissipated had required. Source [4]Not applicable-The TOXDISP model was used to determine concen was used to determine model TOXDISP [4]Not applicable-The [1]Temporary Emergency Exposure Limits (TEEL). Limits Exposure Emergency [1]Temporary [2]Emergency Respon [3]ALOHA does not report values after 1 hour because it assumes it assumes because 1 hour values after report [3]ALOHA does not [8] A comparison study was done using the ALOHA model with n-Hept with model ALOHA the using was done study A comparison [8] [7] The worst-case meteorological conditions determined for each determined conditions [7] worst-case meteorological The [6]TheFLACS modelwas usedto determine that the carbonmonoxide [5]Not applicable-thematerial isan as Offsite Offsite (GulfMark) Offsite (OXEA Offsite Corp.)
2.2S-62 Nearby Industrial, Transportation, and Military Facilities Rev. 12
STP 3 & 4 Final Safety Analysis Report Site Location Site Miles !! Major State Route State Major Populated Place Populated Route State Other to MarketFarm Road Other Road Pacific Union Fe Santa Northern Burlington Area Industrial ! ( 60 521 356 U V ° U V ¬ City or Town Road Railroad Other 01234 Source Data: Oxea http://www.oxea-chemicals.com/index.php? content=01030000&lang=en&PHPSESSID=4 4fbf50fcc23b5964bb6ce21b072dd05 LP Chemicals, Equistar http://www.lyondell.com/Lyondell/Aboutus/ WorldWideLocations/NorthAmerica/USA/ Texas/Matagorda_TX_USA.htm Gulfstream Authority, of Bay City Port Agenda, Meeting 8. Item 2007, 22, April http://www.portofbaycity.com/meetings/ Agenda070412.pdf GulfMark for Institute of Engineers, Corps Army U.S. Resources, Navigation Data Center Water p 11. 26, No. Series Port http://www.iwr.usace.army.mil/ndc/ports/pdf /ps/ps26.pdf to MarketFarm Roads: http://web.wtez.net/c/g/cg63550/highways/ fm/matagorda.htm 2005. USA, StreetMap and Maps & Data ESRI, N Matagorda WWTP 60 U V Wadsworth 521 ° ¬ 2668 ° Oxea Corp. ¬ Chemical Plant Chemical Equistar Chemicals, LP Chemicals, Equistar Matagorda 3057 ° ¬ Port of City Bay Port Energy GulfMark Colorado River Gulfstream Terminal and Mktg. Terminal Gulfstream STP 1 & 2 Figure 2.2S-1 Site Vicinity Map Site Vicinity 2.2S-1 Figure Matagorda Co. 1468 ° ¬ STP 3 & 4 356 U V 521 ° ¬ Cooling Reservoir 5-mile radius El Maton El 1095 ° ¬ 2853 ° ¬ 35 Ashby U V
Nearby Industrial, Transportation, and Military Facilities 2.2S-63 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.2S-2 Pipeline and Oil/Gas Well Map and Oil/Gas Well Pipeline Figure 2.2S-2
2.2S-64 Nearby Industrial, Transportation, and Military Facilities Rev. 12
STP 3 & 4 Final Safety Analysis Report Site Location Site N Miles Restricted Area Restricted Class E (sfc) Airspace E (sfc) Class Regulatory Limit of Influence miles) (10 ClassAirspace E Low Altitude FederalAirways ! Airport: AsphaltAirport:Runway Airport: Runway Turf Heliport H ( (( ( ( ( (
( V31 012345 Source Data: Administration Aviation Federal U.S. SectionalAeronautical Chart, 1:500,000 Houston South, 77th Edition, March 16, 2006 ESRI, Data & Maps and StreetMap USA, 2005. Bay City ! ( H ( ( ( Bay East Matagorda Matagorda Shore 10-mile radius RESTRICTED Fehmel
! ( V-70
STP 3 & 4 River
H
Matagorda Bay ( ( ( Colorado HeliportSTP ! ( (( ( ( Figure 2.2S-3 Airport/Airways Map 2.2S-3 Airport/Airways Figure WD CorniliusWD Rch ON ON CABLE TO 15000 MSL
Cooling Pond
CAUTION: UNMARKED BALLOON V-20
Matagorda County Matagorda V-13 H ( ( ( ( (( ( (
Trull
Bay V-407 Tres Wagner Palacios Airspace Class E (sfc) E Class Palacios Municipal
Nearby Industrial, Transportation, and Military Facilities 2.2S-65 Rev. 12 STP 3 & 4 Final Safety Analysis Report
2.2SA Explosion Methodology Regulatory Guide 1.206 requires COL applicants to determine on the basis of the information provided in the FSAR Sections 2.2.1 and 2.2.2 the potential accidents to be considered as design-basis events and to identify the potential effects of those accidents on the nuclear plant in terms of design parameters (e.g., overpressure) or physical phenomena (e.g., concentration of flammable or toxic cloud outside building structures). Design-basis events internal and external to the nuclear plant are defined as those accidents that have a probability of occurrence on the order of magnitude of 10-7 per year or greater; and potential consequences serious enough to affect the safety of the plant to the extent that the guidelines in 10 CFR Part 100 could be exceeded. One of the accident categories considered in selecting design-basis events is explosions. Accidents involving detonations of high explosives, munitions, chemicals, or liquid and gaseous fuels for facilities and activities in the vicinity of the plant or on-site, where such materials are processed, stored, used, or transported in quantity are considered.
An explosion is defined as a sudden and violent release of high-pressure gases into the environment. The release must be sufficiently fast so that energy contained in the high-pressure gas dissipates in a shock wave. (Reference 2.2SA-6) The strength of the wave is measured in terms of overpressures (maximum pressure in the wave in excess of normal atmospheric pressure). Explosions come in the form of detonations or deflagrations. A detonation is the propagation of a combustion zone at a velocity that is greater than the speed of sound in the un-reacted medium. A deflagration is the propagation of a combustion zone at a velocity that is less than the speed of sound in the un-reacted medium. (Reference 2.2SA-4) For an explosion to occur, the following elements must exist simultaneously:
a flammable mixture (components are thoroughly mixed and are present at a concentration that falls within a flammable composition boundary) consisting of a fuel and oxygen, usually air, or other oxidant
a means of ignition
an enclosure or confinement (Reference 2.2SA-6)
Whether an explosion is possible depends in large measure on the physical state of a chemical. In the case of liquids, flammable and combustible liquids often appear to ignite as liquids. However, it is actually the vapors above the liquid source that ignite. (Reference 2.2SA-5, 5.1.2.1.1) For flammable liquids at atmospheric pressure, an explosion will occur only if the non-oxidized, energized fluid is in the gas or vapor form at correct concentrations in air. Physical explosions may also occur with super-heated liquids that flash-evaporate upon the sudden release of the liquid. (Reference 2.2SA- 6) The concentrations of formed vapors or gases have an upper and lower bound known as the upper flammable limit (UFL) and the lower flammable limit (LFL). Below the LFL, the percentage volume of fuel is too low to sustain propagation. Above the UFL, the percentage volume of oxygen is too low to sustain propagation. (Reference 2.2SA-5, 5.1.2.2.4)
2.2S-66 Nearby Industrial, Transportation, and Military Facilities Rev. 12 STP 3 & 4 Final Safety Analysis Report
Two explosion scenarios are evaluated for each flammable chemical capable of sustaining an explosion. The first scenario involves the rupture of a vessel whereby the entire contents of the vessel are released and an immediate deflagration/detonation ensues. That is, upon immediate release, the contents of the vessel are assumed to be capable of supporting an explosion upon detonation (i.e., flammable liquids are present in the gas/vapor phase between the UFL and LFL). The second scenario involves the release of the entire contents of the vessel whereby the gas (or vapors formed from a liquid spill) travel toward the nearest safety-related system, structure, or component and mix sufficiently with oxygen for the vapor cloud to reach concentrations between the UFL and LFL creating the conditions necessary for a vapor cloud explosion whereby detonation occurs. The methodology presented below is representative of the first scenario. (A separate methodology using the Areal Locations of Hazardous Atmospheres (ALOHA) model is used for the second scenario.).
2.2SA.1 Methodology for Explosion (TNT Equivalence Calculation-Scenario 1) An explanation of the methodology developed is broken up into three sections based on the phase of the chemical during storage/transportation: atmospheric liquids; liquefied gases; and gases.
2.2SA.1.1 Atmospheric liquids For atmospheric liquids, the allowable and actual distances of hazardous chemicals transported or stored were determined in accordance with RG 1.91, Revision 1. (Reference 2.2SA-7) Regulatory Guide 1.91 cites 1 psi (6.9 kPa) as a conservative value of positive incident over pressure below which no significant damage would be expected. Regulatory Guide 1.91 defines this safe distance by the Hopkinson Scaling Law Relationship:
R≥ kW1/3
Where R is the distance in feet from an exploding charge of W pounds of equivalent TNT and k is the scaled ground distance constant at a given overpressure (for 1 psi, the value of the constant k is 45 feet/lbs3). (Reference 2.2SA-7)
In the case of atmospheric liquids, where only that portion in the vapor phase between the UFL and LFL is available to sustain an explosion, the guidance for determining the TNT equivalent, W, in RG 1.91 is not appropriate. That is, when determining the equivalent mass of TNT available for detonation, the mass of a chemical in the vapor phase cannot occupy the same volume under atmospheric conditions as the same mass of the chemical in its liquid phase. Further, upon release of the full contents of a vessel filled with liquid, vaporization of the total mass of the liquid release would not occur instantaneously in the case of liquids stored at atmospheric pressure or below their boiling points. During this phase change, dispersion and mixing would occur—the ALOHA dispersion model is used to model this phenomenon (Scenario 2). Therefore, the methodology employed considers the maximum gas or vapor within the storage as explosive. Thus, for atmospheric liquid storage, this maximum gas or vapor would involve the container to be completely empty of liquid and filled only with air and fuel
Nearby Industrial, Transportation, and Military Facilities 2.2S-67 Rev. 12 STP 3 & 4 Final Safety Analysis Report
vapor at UFL conditions per NUREG-1805. (Note, Scenario 2 conservatively assumes that the entire contents of the vessel are spilled in a 1cm thick puddle under very stable atmospheric conditions to maximize volatilization—a vapor cloud explosion is then modeled using the ALOHA model)
Therefore, for atmospheric liquids, the TNT mass equivalent, W, was determined following guidance in NUREG-1805, where
W= (Mvapor*∆Hc*Yf)/2000
Where Mvapor is the flammable vapor mass (lbs), ∆Hc is the heat of combustion (Btu/lb), and Yf is the explosion yield factor. 2.2SA.1.1.2 Example of Atmospheric Liquid and Vapor Mass Calculation—Gasoline Chemical Properties of Automotive Gasoline (Reference 2.2SA-1)
Lower Flammability Limit 1.4% Upper Flammability Limit 7.4% Vapor Specific Gravity 3.4
To determine the flammable mass:
Vvap = Vvessel * UFL Where: 3 Vvap= flammable vapor volume at UFL, ft Vvessel = liquid (tank) volume, ft3 UFL= upper flammability limit
ρvap=ρair * SGvap Where: 3 3 ρair=air density, lb/ft (0.074 lb/ft ) (Reference 2.2SA-2) 3 ρvap=vapor density, lb/ft SGvap=vapor specific gravity
Mvap=Vvap * ρvap Where: Mvap= flammable vapor mass, lbs
And: Vvessel= 9,000 gal = 9,000gal * 0.13368 ft3/gal = 1,203.12 ft3 3 3 Vvap= 1,203.12 ft * 7.4%= 89.0309 ft 3 3 ρvap= (0.074 lb/ft ) * 3.4 = 0.2516 lb/ft 3 3 Mvap= 89.03 ft * 0.2516 lb/ft = 22 lbs.
2.2S-68 Nearby Industrial, Transportation, and Military Facilities Rev. 12 STP 3 & 4 Final Safety Analysis Report
Therefore: WTNT=(22 * 18,720 * 100%) / 2,000 (Reference 2.2SA-6)
(Note: A 100% yield factor will be attributed to the explosion—this is very conservative because 100% yield cannot be achieved) (Reference 2.2SA-3)
W=205.92 lbs
R≥kW⅓ (Reference 2.2SA-7)
R≥ 45 (206)⅓
R≥ 266 ft
2.2SA.1.2 Liquefied Gases For liquefied gases, the entire mass is considered as a flammable gas/vapor because a sudden tank rupture would entail the release of a majority of the contents in the vapor/aerosol form and a confined explosion could possibly ensue (i.e., the liquid would violently expand and mix with air while changing states from the liquid phase to a vapor/aerosol phase).
Again, for liquefied gases, the allowable and actual distances of hazardous chemicals transported or stored were determined in accordance with NRC Regulatory Guide 1.91.
In this case the entire mass is conservatively considered available for detonation, the equivalent mass of TNT, W, is calculated as follows:
W=E/2000 lb (NUREG-1805, where E is the blast wave energy) E= Mflammable * ∆Hc* Yf (NUREG-1805, where Yf is the explosion yield factor)
2.2SA.1.2.1 Example of Liquefied Gases Calculation--Ethylene:
Quantity: 470,000 lb
Flammable mass (Mflammable): 470,000 lb
Heat of combustion (∆Hc) (Btu/lb): 20,290 (Reference 2.2SA-1)
E=(470,000 lbs) * (20,290) *(100%) (Reference 2.2SA-6) E= 9.54E9
W= (9.54E9) / 2000 W=4.76815E6 lbs.
R≥ 7,574.1 ft
Nearby Industrial, Transportation, and Military Facilities 2.2S-69 Rev. 12 STP 3 & 4 Final Safety Analysis Report
2.2SA.1.3 Gases For pressurized gases, the allowable and actual distances of hazardous chemicals transported or stored were determined in accordance with RG 1.91.
As in the evaluation of liquefied gases, the entire mass is conservatively considered as a flammable gas and available for detonation because a sudden tank rupture would entail the rapid release of a majority of the contents in the vapor/gas phase and a confined explosion could possibly ensue. Therefore, the MTNT, is calculated as follows:
W=E/2000 (NUREG-1805, where E is the blast wave energy) E= Mflammable * ∆Hc* Yf (NUREG-1805, where Yf is the explosion yield factor)
2.2SA.1.3.1 Example of Pressurized Gas—Hydrogen:
3 Quantity: 100,200 ft
Vapor Specific Gravity: 0.067 (Reference 2.2SA-1)
Heat of Combustion: 50,080 Btu/lb (Reference 2.2SA-1)
ρvap=ρair * SGvap Where: 3 3 ρair=air density, lb/ft (0.074 lb/ft ) (Reference 2.2SA-2) 3 ρvap=vapor density, lb/ft SGvap=vapor specific gravity
Mvap=Vvap * ρvap Where: Mvap= flammable vapor mass, lbs 3 3 ρvap= (0.074 lb/ft ) * 0.067= 0.004958 lb/ft 3 3 Mvap= 100,200 ft * 0.005 lb/ft = 503.51 lb
W= (503.51lb * 50,080 Btu/lb) / (2,000 Btu/lb) = 12,607.77 lbs
R≥ 45 * (12,607.77)⅓ = 1,047.35 ft
2.2S-70 Nearby Industrial, Transportation, and Military Facilities Rev. 12 STP 3 & 4 Final Safety Analysis Report
2.2SA.2 References 2.2SA-1 Chemical Hazards Response Information System (CHRIS), United States Coast Guard, November 1998.
2.2SA-2 “Flow of Fluids through Valves, Fittings and Pipes.” Crane Valves North America. 1988.
2.2SA-3 Factory Mutual Global Property Loss Prevention Data Sheets, Data Sheet 7-42, Guidelines for Evaluating the Effects of Vapor Cloud Explosions Using a TNT Equivalency Method. Section 3.4, September 2006.
2.2SA-4 NFPA 68, Guide for Venting of Deflagrations, 2002 Edition, National Fire Protection Association.
2.2SA-5 NFPA 921, Guide for Fire and Explosion Investigations, 2004 Edition, National Fire Protection Association.
2.2SA-6 NUREG-1805, Fire Dynamics Tools (FDT s):Quantitative Fire Hazard Analysis Methods for the U.S. Nuclear Regulatory Commission Fire Protection Inspection Program, December 2004.
2.2SA-7 Regulatory Guide 1.91, Rev. 1, Evaluations of Explosions Postulated to Occur on Transportation Routes Near Nuclear Power Plants, U.S. Nuclear Regulatory Commission, February 1978.
Nearby Industrial, Transportation, and Military Facilities 2.2S-71/72
Rev. 12
STP 3 & 4 Final Safety Analysis Report
2.3 COL License Information 2.3.1 Envelope of Standard Plant Design Parameters 2.3.1.1 Non-Seismic Design Parameters The following site-specific supplement addresses COL License Information Item 2.1.
Subsection 2.2.1 provides a discussion of analyses performed to demonstrate that the overall set of STP site characteristics do not exceed the capability of the reference ABWR design for the design bases events.
2.3.1.2 Seismic Design Parameters The following site-specific supplement addresses COL License Information Item 2.2.
The information demonstrating that the STP 3 & 4 site-specific conditions meet the specified SSE ground motion is discussed in Subsection 2.5S.2, and the information demonstrating that the STP 3 & 4 site-specific conditions meet the specified bearing capacity is discussed in Subsection 2.5S.4.
2.3.2 Standard Review Plan Site Characteristics The differences from Standard Review Plan (SRP) Section II Acceptance Criteria for the STP site-specific characteristics are provided in Table 2.1-1. Where such differences exist, the table provides supplementary information as to whether the SRP limits specified for the reference ABWR design are met for the STP 3 & 4 site, and a roadmap to the FSAR sections where further discussion of the site characteristic is provided. In addition, the STP site-specific characteristics are addressed in the FSAR sections identified in the following subsections.
2.3.2.1 Site Location and Description The following site-specific supplement addresses COL License Information Item 2.3.
Site-specific information related to the STP 3 & 4 site location, including political subdivisions, natural and man-made features, population, highways, railways, waterways, and other significant features of the area is provided in Subsection 2.1S.1.
2.3.2.2 Exclusion Area Authority and Control The following site-specific supplement addresses COL License Information Item 2.4.
The site-specific information related to activities that may be permitted within the designated exclusion area for STP 3 & 4 is provided in Subsection 2.1S.2.
2.3.2.3 Population Distribution The following site-specific supplement addresses COL License Information Item 2.5.
The population data for the STP site environs is provided in Subsection 2.1S.3.
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STP 3 & 4 Final Safety Analysis Report
2.3.2.4 Identification of Potential Hazards in Site Vicinity The following site-specific supplement addresses COL License Information Item 2.6.
Information with respect to industrial, military, and transportation facilities and routes to establish the presence and magnitude of potential external hazards at the STP site is provided in Subsections 2.2S.1 and 2.2S.2.
2.3.2.5 Evaluation of Potential Accidents The following site-specific supplement addresses COL License Information Item 2.7.
The potential accident situations in the vicinity of the STP site and the bases for which these potential accidents are accommodated in the design are provided in Subsection 2.2S.3.
2.3.2.6 External Impact Hazards The following site-specific supplemental information addresses COL License Information Item 2.8.
A review and evaluation of the effects on the protection criteria of external impact hazards at the STP site, such as general aviation or nearby explosions, is provided in Subsection 2.2S.3.
2.3.2.7 Local Meteorology The following site-specific supplement addresses COL License Information Item 2.9.
A description of the local meteorology for the STP site is provided in Subsection 2.3S.2.
2.3.2.8 Onsite Meteorological Measurements Program The following site-specific supplement addresses COL License Information Item 2.10.
A description of the onsite meteorological measurements program for STP 3 & 4 is provided in Subsection 2.3S.3.
2.3.2.9 Short-Term Dispersion Estimates for Accidental Atmospheric Releases The following site-specific supplement addresses COL License Information Item 2.11.
The STP 3 & 4 site-specific short-term dispersion estimates are provided in Subsection 2.3S.4. This information is used to ensure that the envelope values provided in Tables 15.6-3, 15.6-7, 15.6-13, 15.6-14 and 15.6-18 of relative concentrations are not exceeded for the STP site.
2.3.2.10 Long-Term Diffusion Estimates The following site-specific supplement addresses COL License Information Item 2.12.
2.3-2 COL License Information Rev. 12
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The annual average atmospheric dispersion values for reactive releases are provided in Subsection 2.3S.5.
2.3.2.11 Hydrologic Description The following site-specific supplement addresses COL License Information Item 2.13.
A detailed description of all major hydrologic features on or in the vicinity of the STP site is provided in Subsection 2.4S.1. A specific description of the site and all safety- related elevations, structures, exterior accesses, equipment, and systems from the standpoint of hydrology considerations is also provided in Subsection 2.4S.1.
2.3.2.12 Floods The following site-specific supplement addresses COL License Information Item 2.14.
Site-specific information related to historical flooding and potential flooding at the STP site, including flood history, flood design considerations, and effects of local intense precipitation, is provided in Subsection 2.4S.2.
2.3.2.13 Probable Maximum Flood on Streams and Rivers The following site-specific supplement addresses COL License Information Item 2.15.
Site-specific information related to design-basis flooding at the STP site and the extent of flood protection required for the STP 3 & 4 safety-related structures, systems, and components (SSCs) is provided in Section 2.4S.3.
2.3.2.14 Ice Effects The following site-specific supplement addresses COL License Information Item 2.16.
The evaluation demonstrating that safety-related facilities and the water supply for STP 3 & 4 are not affected by ice flooding or blockage is provided in Subsection 2.4S.7.
2.3.2.15 Cooling Water Channels and Reservoirs The following site-specific supplement addresses COL License Information Item 2.17.
The basis for the hydraulic design of the main cooling reservoir (MCR) and channels used to transport and impound the cooling water supply for STP 3 & 4 is provided in Subsection 2.4S.8.
2.3.2.16 Channel Diversions The following site-specific supplement addresses COL License Information Item 2.18.
Site-specific information related to channel diversion for the STP site is provided in Subsection 2.4S.9.
2.3.2.17 Flooding Protection Requirements The following site-specific supplement addresses COL License Information Item 2.19.
COL License Information 2.3-3 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Information related to the flooding protection requirements for the STP site is provided in Subsection 2.4S.10.
2.3.2.18 Cooling Water Supply The following site-specific supplement addresses COL License Information Item 2.20.
The natural events that may reduce or limit the available cooling water supply and the measures taken to ensure that an adequate water supply exists to operate and shut down STP 3 & 4 are identified in Subsection 2.4S.11.
2.3.2.19 Accidental Release of Liquid Effluents in Ground and Surface Waters The following site-specific supplement addresses COL License Information Item 2.21.
The ability of the surface water environment at the STP site to disperse, dilute, or concentrate accidental releases is discussed in Subsection 2.4S.13. The effects of these releases on existing and known future uses of surface water resources are discussed in Subsections 2.4S.12 and 2.4S.13.
2.3.2.20 Technical Specifications and Emergency Operation Requirement The following site-specific supplement addresses COL License Information Item 2.22.
Flood protection measures for the STP 3 & 4 safety-related facilities, and provisions used to ensure that an adequate water supply is available to shut down and cool the reactor, are described in Subsection 2.4S.14. The need for technical specifications and/or emergency procedures to ensure these measures is also discussed in Subsection 2.4S.14.
2.3.2.21 Basic Geological and Seismic Information The following site-specific supplement addresses COL License Information Item 2.23.
Site-specific information related to regional and site physiography, geomorphology, stratigraphy, lithology, and tectonics for the STP site is provided in Subsection 2.5S.1.
2.3.2.22 Vibratory Ground Motion The following site-specific supplement addresses COL License Information Item 2.24.
The STP 3 & 4 site-specific geological, seismological, and geotechnical data, including a comparison of the site-specific SSE (ground motion response spectra) to the design ground spectra (certified seismic design response spectra) in Subsection 2.3.1.2, are discussed in Subsection 2.5S.2.
2.3.2.23 Surface Faulting The following site-specific supplement addresses COL License Information Item 2.25.
The site-specific geological data used to evaluate surface faulting at STP 3 & 4 is provided in Subsection 2.5S.3.
2.3-4 COL License Information Rev. 12
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2.3.2.24 Stability of Subsurface Material and Foundation The following site-specific supplement addresses COL License Information Item 2.26.
Information concerning the properties and stability of site-specific soils and rocks under both static and dynamic conditions including the vibratory ground motions associated with the STP site-specific SSE is provided in Subsections 2.5S.2 and 2.5S.4.
2.3.2.25 Site and Facilities The following site-specific supplement addresses COL License Information Item 2.27.
The detailed description of the STP site conditions and geologic features is provided in Subsection 2.5S.1. This description includes site topographical features and the location of various Seismic Category I structures and appurtenances (pipelines, channels, etc.) with respect to the source of normal and emergency cooling water.
2.3.2.26 Field Investigations The following site-specific supplement addresses COL License Information Item 2.28.
A discussion of field investigations conducted at the STP site is provided in Subsection 2.5S.4, including the type, quantity, extent, and purpose of the field explorations. Subsection 2.5S.4 and associated appendices include logs of the borings and test pits and results of geophysical surveys, presented in tables and profiles. Records of field permeability tests and other special field tests are also provided.
2.3.2.27 Laboratory Investigations The following site-specific supplement addresses COL License Information Item 2.29.
The number and type of laboratory tests conducted to assess the STP site and the location of samples taken as part of the field investigations are provided in tabular form in Subsection 2.5S.4. The results of laboratory tests on disturbed and undisturbed soil samples obtained from field investigations are also provided in Subsection 2.5S.4.
2.3.2.28 Subsurface Conditions The following site-specific supplement addresses COL License Information Item 2.30.
Details on subsurface conditions at the STP site are provided in Subsections 2.4S.12, 2.5S.1, 2.5S.2, and 2.5S.4. The subsurface conditions were investigated and the details are provided on the engineering classifications and descriptions of the soils supporting the foundations for STP 3 & 4. The information discussed includes the history of soil deposition and erosion, past and present groundwater levels, other preloading influences, and any soil characteristics that may present a hazard to plant safety. Profiles through the Seismic Category I structures are provided that show generalized subsurface features beneath these structures.
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2.3.2.29 Excavation and Backfilling for Foundation Construction The following site-specific supplement addresses COL License Information Item 2.31.
A description of the excavation and backfilling required for construction of the STP 3 & 4 foundations is provided in Subsection 2.5S.4. The site-specific soil properties below the base of the foundations are described. This description includes the configuration, along with detailed longitudinal sections and cross-sections of other safety-related STP 3 & 4 structures, including the ultimate heat sinks (UHS) and Seismic Category I buried pipes and electrical ducts. Data concerning the extent (horizontally and vertically) of all Seismic Category I excavations, fills, and slopes are provided. The locations, elevations, and grades for excavated slopes are described and shown on plot plans and typical cross-sections. A discussion of excavating and dewatering methods, excavation depths below grade, field inspection and testing of excavations, protection of foundation excavations from deterioration during construction, and the foundation dental fill work is provided in Subsections 2.4S.12 and 2.5S.4. The sources, quantities, and static and dynamic engineering properties of borrowed materials are described.
2.3.2.30 Effect of Groundwater The following site-specific supplement addresses COL License Information Item 2.32.
An analysis of the groundwater conditions at the STP site is provided in Subsections 2.4S.12 and 2.5S.4, including the effects of groundwater on site geotechnical properties such as total and effective unit weights, cohesion and angle of internal friction, and dynamic soil properties.
2.3.2.31 Liquefaction Potential The following site-specific supplement addresses COL License Information Item 2.33.
The liquefaction potential for the STP site under and around all Seismic Category I structures, including Category I buried pipelines and electrical ducts, is addressed in Subsection 2.5S.4. Justification for the selection of the soil properties used in the liquefaction potential evaluation (e.g., laboratory tests, field tests, and published data), the magnitude and duration of the earthquake, and the number of cycles of earthquakes is also provided in Subsection 2.5S.4.
2.3.2.32 Response of Soil and Rock to Dynamic Loading The following site-specific supplement addresses COL License Information Item 2.34.
The dynamic soil properties for the STP site, in terms of shear modulus and material damping as a function of shear strain, are discussed in Subsection 2.5S.4. These strain-dependent properties are used in the determination of the ground motion response spectra (site-specific SSE). Due to the depth to rock at the STP site, only soil properties are investigated for STP 3 & 4.
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2.3.2.33 Minimum Soil Bearing Capacity The following site-specific supplement addresses COL License Information Item 2.35.
Minimum static bearing capacity at the foundation level of the Reactor and Control Buildings is discussed in Subsection 2.5S.4. Bearing capacity of the foundation material for the other STP 3 & 4 safety-related facilities is also discussed in Subsection 2.5S.4.
2.3.2.34 Earth Pressures The following site-specific supplement addresses COL License Information Item 2.36.
The site-specific evaluation of static and dynamic lateral earth pressures and hydrostatic groundwater pressures acting on the STP 3 & 4 safety-related facilities is provided in Subsection 2.5S.4.
2.3.2.35 Soil Properties for Seismic Analysis of Buried Pipes The following site-specific supplement addresses COL License Information Item 2.37.
The soil properties used for the seismic analysis of Seismic Category I buried pipes and electrical conduits for STP 3 & 4 are provided in Subsection 2.5S.4.
2.3.2.36 Static and Dynamic Stability of Facilities The following site-specific supplement addresses COL License Information Item 2.38.
A description of the static and dynamic stability of the STP 3 & 4 facilities is provided in Subsection 2.5S.4. This information includes a discussion of the site-specific stability evaluation performed for the safety-related facilities including foundation rebound, settlement, differential settlement, and bearing capacity. The assumptions made in the stability analyses will be confirmed by as-built data, and the FSAR will be updated in accordance with 10 CFR 50.71(e) to provide confirmation that the as-built data are bounded by the assumptions. (COM 2.3-1)
2.3.2.37 Subsurface Instrumentation The following site-specific supplement addresses COL License Information Item 2.39.
Instrumentation used for surveillance of the performance of the foundations for STP 3 & 4 safety-related structures is described in Subsection 2.5S.4. Monitoring program specifications, developed during the detailed stage of the project, addresses issues such as the installation of a sufficient quantity of instruments in the excavation zone, monitoring and recording frequency, and evaluation of the magnitude of subgrade rebound and structure settlement during excavation, dewatering, and subsequent foundation construction.
2.3.2.38 Stability of Slopes The following site-specific supplement addresses COL License Information Item 2.40.
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Information concerning the static and dynamic stability of all soil and rock slopes at the STP site whose failure could adversely affect plant safety is provided in Subsection 2.5S.5.
2.3.2.39 Embankments and Dams The following site-specific supplement addresses COL License Information Item 2.41.
There are no embankments or dams that impound water required for safe operation (and shutdown) of STP 3 & 4.
2.3.3 CRAC 2 Computer Code Calculations The following site-specific supplement addresses COL License Information Item 2.42.
Subsection 2.2.2 provides information regarding compliance with acceptance criteria, data input and the analyses for determining STP site acceptability for severe accidents.
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2.3S Meteorology 2.3S.1 Regional Climatology This subsection addresses various aspects of the climate in the site region and area in the vicinity of the STP 3 & 4 site. Subsection 2.3S.1.1 identifies data resources used to develop these descriptions. Subsection 2.3S.1.2 describes large-scale general climatic features and their relationship to conditions in the site area and vicinity.
Severe weather phenomena considered in the design and operating bases for STP 3 & 4 are discussed in Subsections 2.3S.1.3.1 through 2.3S.1.3.6. These subsections describe observed and/or probabilistic: extreme wind conditions; tornados and related wind and pressure characteristics; tropical cyclones and related effects; precipitation extremes; the frequency and magnitude of hail, snowstorms, and ice storms; and the frequency of thunderstorms and lightning.
Subsection 2.3S.1.4 discusses the long-term temperature and humidity characteristics used to evaluate the performance of the ultimate heat sink (UHS) for STP 3 & 4. Subsection 2.3S.1.5 provides design-basis dry- and wet-bulb temperature statistics representative of the site area to be considered in the design and operating bases of other safety- and nonsafety-related structures, systems, and components. Subsection 2.3S.1.6 characterizes conditions (from a climatological standpoint) in the site area and region that may be restrictive to atmospheric dispersion. Finally, trends in mean and extreme temperature, precipitation conditions, and the occurrences of severe weather events, are addressed in Subsection 2.3S.1.7 in the context of the site’s design bases.
The reference ABWR DCD Tier 1, Table 5.0 and Tier 2, Table 2.0-1, provide several climate-related site parameters on which the ABWR design is based, including extreme wind, tornado, precipitation (for roof design), and ambient design temperature. Site-specific characteristics which correspond to these site parameters are presented or addressed in Subsections 2.3S.1.3.1, 2.3S.1.3.2, 2.3S.1.3.4, and 2.3S.1.5, respectively. Table 2.0-2 compares the ABWR standard plant design parameters with the STP 3 & 4 characteristic values.
2.3S.1.1 Data Sources Several sources of data are used to characterize regional climatological conditions pertinent to the site for STP 3 & 4. The primary sources of data used to characterize local meteorological and climatological conditions representative of the site for STP 3 & 4 include long-term summaries for the first-order National Weather Services (NWS) station at Victoria, Texas, and for 14 other nearby cooperative weather observing stations, as well as measurements from the onsite meteorological monitoring program operated in support of the existing STP 1 & 2. These climatological observing stations are in Matagorda, Wharton, Jackson, Calhoun, Brazoria, Victoria, Fort Bend and Aransas counties: all located in Texas. Table 2.3S-1 identifies the offsite observing stations and lists their approximate distance and direction from STP 3 & 4. Figure 2.3S-1 illustrates these station locations relative to the mid-point between the STP 3 & 4 reactors at the site.
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The objective of selecting nearby, offsite climatological monitoring stations is to demonstrate that the mean and extreme values measured at those locations are reasonably representative of conditions that might be expected to be observed at the STP site. The 50-mile radius circle shown in Figure 2.3S-1 provides a relative indication of the distance between the climate observing stations and the STP site. However, a 50-kilometer (approximately 31-mile) grid spacing is considered to be a reasonable fine mesh grid in current regional climate modeling, so this distance was used as a nominal radius for the station selection process. The identification of stations to be included was based on the following general considerations:
Proximity to the STP site (i.e., within the nominal 50-kilometer radius indicated above, to the extent practicable).
Coverage in all directions surrounding the site (to the extent possible).
Where more than one station exists for a given direction relative to the site, a station was chosen if it contributed one or more extreme conditions (e.g., rainfall, snowfall, maximum and/or minimum temperatures) for that general direction.
Nevertheless, if an overall extreme precipitation or temperature condition was identified for a station located within a reasonable distance beyond the nominal 50- kilometer radius and that extreme condition was considered to be reasonably representative of the site area, that station was also included, regardless of directional coverage.
Normals (i.e., 30-year averages), means, and extremes of temperature, rainfall, and snowfall are based on the following data sources found in References 2.3S-1 through 2.3S-5.
First-order NWS stations also record measurements, typically on an hourly basis, of other weather elements, including winds, several indicators of atmospheric moisture content (i.e., relative humidity, dew point, and wet-bulb temperatures), and barometric pressure, as well as other observations when those conditions occur (e.g., fog, thunderstorms). Victoria, Texas, NWS station is the closest first-order station with consecutive long-term data available. Although the Victoria weather station is located 53 miles to the west of the STP site (slightly longer than the distance defined by NUREG-0800 (Reference 2.3S-6) as “nearby”), the terrain between the STP site and the Victoria station is relatively flat. Additionally, the Victoria station is located at almost the same latitude as the STP site. Therefore, the long-term (30 years) data from the Victoria station was used to describe the general climatic conditions at the STP site. Table 2.3S-2, excerpted from the 2005 local climatological data (LCD) summary for the Victoria station, presents the long-term characteristics of these parameters.
In addition, data from References 2.3S-7 through 2.3S-17 was used in describing climatological characteristics of the STP 3 & 4 site area and region.
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2.3S.1.2 General Climate The STP site is located within the Coastal Prairie region, situated along the Coastal Plain that runs parallel to the Gulf of Mexico and extends from south central Texas to southwestern Louisiana (Reference 2.3S-1). The STP site area is relatively flat; elevation is generally 25 feet above MSL in this region.
The state of Texas is divided into 10 climate divisions. The STP 3 & 4 site is located within the Upper Coastal division, designated as Texas-08, which is situated south of East Texas, bordered by the state of Louisiana on the east, the Gulf of Mexico to the south, and Victoria and Calhoun Counties to the west (Reference 2.3S-17).
The general climate in this region is classified as maritime subtropical (or humid subtropical) and is characterized by mild, short winters; long periods of mild sunny weather in the autumn; somewhat more windy but mild weather in spring; and long, hot summers.
The regional climate is predominately influenced by the Azores high-pressure system (also known as the Azores High). Due to the clockwise circulation around the western extent of the Azores High, maritime tropical air mass characteristics prevail much of the year, especially during the summer with the establishment of the Bermuda High and the Gulf High. Collectively, these systems govern late spring and summer temperature and precipitation patterns. This macro-circulation feature also has an effect on the frequency of high air pollution potential in the STP site region. These characteristics and their relationship to the Bermuda High, especially during the summer and early autumn, are addressed in Subsection 2.3S.1.6.
The influence of this macro-scale circulation feature continues during the transitional seasons (spring and autumn) and winter months; however, it is occasionally disrupted by the passage of synoptic- and meso-scale weather systems. During winter, cold air masses may briefly intrude into the region with the cyclonic northerly flow that follows the passage of low-pressure systems. These systems frequently originate in the continental interior around Colorado or Canada, pick up moisture-laden air due to southwesterly through southeasterly airflow in advance of the system, and result in a variety of precipitation events that include rain, sleet, freezing rain, or mixtures, depending on the temperature characteristics of the weather system itself and the temperature of the underlying air (see Subsection 2.3S.1.3.5).
During the summer months, the Texas coastal sea breeze has a large influence on local and regional climatology near the STP site. The inland coastal plains of Texas heat rapidly during summer days causing a large temperature differential between the land and the relatively cooler Gulf of Mexico. The land/sea temperature contrast during the day creates circulation forming a sea breeze, where cooler, more saturated air pushes inland as the warm inland air rises. Also called the “gulf” breeze, it extends about 50 km inland throughout the day. During a sea breeze, cooler temperatures and higher relative humidity can be expected. The opposite occurs at night, where air over the inland plains cools rapidly while the air over the sea stays relatively warmer, thus forming a land breeze to push off-shore into the Gulf of Mexico.
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Larger, persistent outbreaks of very cold, dry air associated with massive high- pressure systems that move southward out of Canada also occasionally affect the site region (Reference 2.3S-1). However, these weather conditions are moderated significantly by the Gulf of Mexico immediately to the south and due to heating as it passes over the land.
Monthly precipitation exhibits a cyclical pattern, with the predominant maximum occurring in May with 5.12 inches, and a secondary maximum in September with 5.00 inches (see Table 2.3S-2). Because the STP site is located close enough to the Gulf of Mexico (the distance, midpoint between Units 3 & 4 reactor buildings, is 14.67 miles), the strong winds associated with tropical cyclones can have a significant effect on the site area.
2.3S.1.3 Severe Weather This subsection addresses severe weather phenomena that affect the STP site area and region and that are considered in the design and operating bases for STP 3 & 4. These phenomena include: observed and probabilistic extreme wind conditions (Subsection 2.3S.1.3.1); tornados and related wind and pressure characteristics (Subsection 2.3S.1.3.2); tropical cyclones and related effects (Subsection 2.3S.1.3.3); observed and probabilistic precipitation extremes (Subsection 2.3S.1.3.4); the frequency and magnitude of hail, snowstorms, and ice storms (Subsection 2.3S.1.3.5); and the frequencies of thunderstorms and lightning (Subsection 2.3S.1.3.6).
2.3S.1.3.1.1 Extreme Winds To ensure that the design bases for SSCs important to safety include appropriate consideration for the most severe natural phenomena historically reported for the site and surrounding area, the design and operating bases wind loadings on plant structures were determined in accordance with the ASCE-SEI design standard, "Minimum Design Loads for Buildings and Other Structures," (Reference 2.3S-10). This is consistent with the guidance provided in NUREG-0800, Section 2.3.1 (Reference 2.3S-6).
Design wind loading is based on a basic wind speed, which is the "3-second gust speed at 33 feet (10 meters) above the ground in Exposure Category C," as defined in Sections 6.2 and 6.3 of Reference 2.3S-10. The basic wind speed for the STP 3 & 4 site is approximately 125 mph (201 km/h), based on a linear interpolation from the plot of basic wind speeds in Figure 6-1 of ASCE 2007 (Reference 2.3S-10) for that portion of the U.S. that includes the site for STP 3 & 4. From a probabilistic standpoint, a basic wind speed of 125 mph (201 km/h) for the STP 3 & 4 site is associated with a mean recurrence interval of 50 years. Section C6 (Table C6-7) of the ASCE-SEI design standard provides conversion factors for estimating 3-second-gust wind speeds for other recurrence intervals (Reference 2.3S-10). Based on this guidance, the 100-year return period value is determined by multiplying the 50-year return period value by a scaling factor of 1.07, which yields a 100-year return period 3 second-gust wind speed for the site of approximately 134 mph (215 km/h).
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Three-second gust wind speed is always greater than the fastest mile wind speed. In the reference ABWR DCD, the listed extreme of 122 mph is the fastest mile wind speed. This corresponds to a 139 mph 3-second gust; therefore, the calculated 100- year fastest mile 3-second gust related to the reference ABWR DCD is not exceeded.
The reference ABWR DCD Tier 1, Table 5.0 and reference ABWR DCD Tier 2, Table 2.0-1 include the following site parameter values for Extreme Wind, for which the ABWR plant is designed:
177 km/h (110 mph) equivalent to 126 mph (3-second gust) - Basic Wind Speed, 50-year recurrence interval (for design of nonsafety-related structures only)
197 km/h (122 mph) equivalent to 139 mph (3-second gust) - 100-year recurrence interval (for design of safety-related structures only)
Using the data and the methodology recommended in Reference 2.3S-10, both the site-specific 50-year fastest mile basic wind speed and 100-year recurrence interval fastest mile wind for the STP 3 & 4 site are less than or equal to those specified in the reference ABWR.
The NOAA Coastal Services Center (CSC) Hurricane Track Query was also used to review the historical record of tropical cyclone tracks and intensities near the STP 3 & 4 site for the period from 1851 to the present. This review identified eleven tropical cyclones with wind speeds that exceed a design basis wind loading for the STP 3 & 4 site calculated in accordance with Reference 2.3S-10. The top five storms include: Not named 1886 (155 mph sustained wind speed); Not named 1900 (144 mph sustained wind speed); Not named 1932 (144 mph sustained wind speed); Not named 1945 (138 mph sustained wind speed); and Hurricane Carla 1961 (144 mph sustained wind speed). The maximum wind speeds are not measured by anemometers for these eleven storms and estimates are from other data. Additionally, CSC Hurricane Track Query is typically not used for the determination of design wind loading for buildings. However, as explained in Subsection 2.3S.1.3.3.2, Site Specific Design-Basis Hurricane, the STP site specific design-basis hurricane windspeed, which is listed in Table 2.0-2, was determined in accordance with Regulatory Guide 1.221 (Reference 2.3S-70).
Using the data and the methodology recommended in Reference 2.3S-10 to verify design basis wind loadings are less than or equal to those specified in the reference ABWR, without specific consideration of the CSC Hurricane Track Query data, satisfies the requirements of ASCE/SEI-7 (Reference 2.3S-10) and NUREG-0800 (Reference 2.3S-6). The ASCE/SEI-7 design standard wind speed map considered wind speeds of historically reported hurricanes and is updated periodically. However, as explained in Subsection 2.3S.1.3.1.2, STP Site Hurricane Wind Speed and Associated Missile Hazard, the STP 3 & 4 design incorporates the guidance provided in Regulatory Guide 1.221 for hurricane wind speed and the associated missile hazard. Therefore, appropriate consideration has been given to the most severe tropical cyclones and the consequences of these storms.
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2.3S.1.3.1.2 STP Site Hurricane Wind Speed and Associated Missile Hazard Regulatory Guide 1.221, "Design-Basis Hurricane and Hurricane Missiles for Nuclear Power Plants," (Reference 2.3S-70) provides guidance for selecting the design-basis hurricane windspeed and hurricane-generated missiles.
The STP 3 & 4 design incorporates the guidance provided in Regulatory Guide 1.221 by the inclusion of a Site Characteristic requirement in Table 2.0-2 for hurricane wind speed and the associated missile hazard. Subsection 2.3S.1.3.3.2, Site Specific Design-Basis Hurricane, describes how hurricane windspeed and hurricane missiles are addressed consistent with guidance provided in Regulatory Guide 1.221.
2.3S.1.3.2 Tornados The design-basis tornado (DBT) characteristics applicable to structures, systems, and components important to safety include the following parameters as identified in Regulatory Guide (RG) 1.76,(Reference 2.3S-18).
Based on Figure 1 of RG 1.76, (Reference 2.3S-18), the STP site is located within Tornado Intensity Region II, but is directly adjacent to Tornado Intensity Region I. In determining the tornado intensity region applicable to the STP site, information in Revision 2 of NUREG/CR-4461 (Reference 2.3S-19), was taken into consideration. That document was the basis for most of the technical revisions to RG 1.76, (Reference 2.3S-18). Based on Rev. 1 of RG 1.76, (Reference 2.3S-18), the DBT characteristics for Tornado Intensity Region II applicable STP 3 & 4 site are:
Maximum wind speed = 200 mph (89 m/sec)
Translational speed = 40 mph (18 m/sec)
Maximum rotational speed = 160 mph (72 m/sec)
Radius of maximum rotational speed = 150 ft (45.7 m)
Pressure drop = 0.9 pound per square inch (psi) (63 mb), and
Rate of pressure drop = 0.4 psi/sec (25 mb/sec)
In the reference ABWR DCD Tier 1, Table 5.0 lists two tornado-related site parameters (i.e., maximum tornado wind speed and maximum pressure drop) and corresponding site parameter values. A complete list of tornado-related site parameters (consistent with the DBT parameters in RG 1.76, (Reference 2.3S-18) is given in the reference ABWR DCD Tier 2, Table 2.0-1, and includes the following site parameter values for which the ABWR plant is designed:
Maximum tornado wind speed = 483 km/h (300 mph)
Translational velocity = 97 km/h (60 mph)
Maximum rotational speed = 386 km/h (240 mph)
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Radius = 45.7 m (150 ft)
Maximum pressure drop = 13.827 kPaD (2.0 psi), and
Rate of pressure drop = 8.277 kPa/sec (1.2 psi/sec)
The reference ABWR DCD DBT values bound the STP site-specific DBT values.
Tornadoes reported in the contiguous United States from 1950 through 2006 were used to determine tornado frequency (NCDC, Storm Events, http://www4.ncdc.noaa.gov/cgi-win/wwcgi.dll?wwevent~storms, accessed July 2007).
The STP site is located about N 28° 48’ (latitude) and W 96° 3' (longitude). Figure 1 of Regulatory Guide 1.76 uses the 2° boxes to classify tornado intensity regions for the contiguous United States. As a time saving alternative to account for number of tornadoes that occurred nearby the STP site, a circular area was used in order to be equivalent to the approach used by a data retrieval application developed by the National Severe Storms Laboratory (NSSL), called Severe Plot. (http://www.spc.noaa.gov/software/svrplot2). A circle with a 77.91 mile-radius centered at the STP site covers the same area as the 2° box. To be conservative, all tornadoes were included in this analysis for counties that are either totally or partially covered by the 77.91 mile-radius circle.
Based on the NCDC Storm Events database referenced above, there are 902 tornado occurrences within these counties. For tornadoes that occurred within the nearby counties, on a monthly basis, May and September had the highest frequencies. Among the 902 tornado counts, 153 (17%) occurred in May and 130 (14.4%) occurred in September. On seasonal basis, Fall had the highest count (34.2%) and Spring had the second highest count (31%).
2.3S.1.3.3.1 Tropical Cyclones Tropical cyclones include not only hurricanes and tropical storms, but systems classified as tropical depressions, subtropical depressions, and extra-tropical storms, among others. This characterization considers all tropical cyclones (rather than systems classified only as hurricanes and tropical storms) because storm classifications are generally downgraded once landfall occurs and the system weakens, although they may still result in significant rainfall events as they travel through the site region.
National Oceanic and Atmospheric Administration’s (NOAA) Coastal Services Center provides a comprehensive historical database, extending from 1851 through 2006, of tropical cyclone tracks based on information compiled by the National Hurricane Center. This database indicates that a total of 76 tropical cyclone centers or storm tracks have passed within a 100-nautical-mile radius of the STP 3 & 4 site during this historical period (Reference 2.3S-12). Storm classifications and respective frequencies of occurrence over this 155-year period of record are as follows:
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Hurricanes – Category 5 (1), Category 4 (6), Category 3 (4), Category 2 (5), Category 1 (22)
Tropical storms – 35
Tropical depressions – 3
Subtropical storms – 0
Subtropical depressions – 0
Extra-tropical storms – 0
Tropical cyclones within this 100-nautical-mile radius have occurred as early as June and as late as October, with the highest frequency (22 out of 76 events) recorded during September. August accounts for 19 events, indicating that almost 54% of the tropical cyclones that affect the site area occur from late summer to early autumn. Frequencies during the months of June and July are approximately equal to one another but approximately 30% lower than during the peak months of September and August; intensity levels are lower as well.
Hurricanes of all categories have passed within 100 nautical miles of the site during the month of September; 6 of these 10 occurrences were classified as Category 1 storms. The only Category 5 storm track within this radial distance was Hurricane Carla in September 1961. Twelve hurricanes have been recorded within 100 nautical miles of the site during August. While none of these reached Category 5 status, the distribution of other hurricane classifications indicates August as having higher intensities on a long-term climatological basis - that is, Category 4 (4), Category 3 (2), Category 2 (2), and Category 1 (4).
Only one-third of the individual NWS station 24-hour rainfall records were established as a result of precipitation associated with tropical cyclones that passed within a 100- nautical-mile radius of the STP site. In July 1979, tropical depression Claudette set 24- hour rainfall records at Freeport 2 NW (16.72 inches.) and Angleton 2 W (14.36 inches) cooperative weather stations (Reference 2.3S-2). In June 1960, a tropical depression that had not been named set 24-hour rainfall records at Danevang 1W ( 12.96 inches), Maurbro (14.80 inches) and Point Comfort (14.65 inches) cooperative weather stations (Reference 2.3S-2).
2.3S.1.3.3.2 Site Specific Design-Basis Hurricane The STP site specific design-basis hurricane windspeed listed in Table 2.0-2 was determined in accordance with Regulatory Guide 1.221 (Reference 2.3S-70). The resulting hurricane generated missile spectrum was determined in accordance with Regulatory Guide 1.221 as described in Subsection 3H.11.
2.3S.1.3.4 Precipitation Extremes Because precipitation is a point measurement, mean and extreme statistics, such as individual storm totals, or daily totals, or cumulative monthly totals, typically vary from
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station to station. Assessing the variability of precipitation means and extremes over the STP site area, in an effort to evaluate whether the available long-term data is representative of conditions at the site, is largely dependent on station coverage. Monthly and daily historical precipitation extremes for rainfall and snowfall are presented in Table 2.3S-3 for the nearby climatological observing stations.
The highest 24-hour rainfall total in the site area, 20.85 inches, on October 19, 1983, at the Bay City Waterworks cooperative weather observing station (Reference 2.3S- 57), approximately 13 miles NNE of the STP site, was not associated with a tropical cyclone originating in or passing through the Gulf of Mexico. This extreme rainfall event was one of many over southeast Texas caused by a synoptic situation that included a steady stream of tropical moisture into the region, and a slow moving frontal boundary that provided a source of lift and supported widespread and continual thunderstorm development (Reference 2.3S-59).
The highest monthly rainfall total for the site area, 31.61 inches during September 1979, was recorded at the Freeport 2NW cooperative observing station, located approximately 43 miles ENE of the STP site. There does not appear to be any clear relationship between the rainfall recorded during extreme events, whether on a 24- hour or monthly basis, and distance inland within the area considered around the STP site (see Figure 2.3S-1). Therefore, based on the range of the maximum recorded 24- hour and monthly rainfall totals among these stations, the areal distribution of these climatological observing stations around the site, and their proximity to the site, the data suggests that rainfall extremes close to the upper limits of the respective maxima might reasonably be expected to occur at the STP site.
Although the disruptive effects of any winter storm accompanied by frozen precipitation can be significant in South Texas, storms that produce large measurable amounts of snow are rare. As Table 2.3S-3 indicates, 24-hour and monthly total station records have been established over a number of years based on the available periods of record. The most recent event, the Christmas Storm of 2004, was responsible for the overall highest 24-hour and monthly totals recorded for the site area - 10.5 inches, in both cases – measured at the Danevang 1W observing station, approximately 20 miles NNW of the STP site (Reference 2.3S-5).
Assessing normal and extreme winter precipitation loads on the roofs of seismic category I structures considers these climate-related components:
The normal winter precipitation event, which is defined as the highest ground-level weight (in lb/ft2) among (1) the 100-year return period snowpack, (2) the historical maximum snowpack, (3) the 100-year return period snowfall event, or (4) the historical maximum snowfall event in the site region.
The extreme frozen winter precipitation event, which is defined as the higher ground-level weight (in lb/ft2) between (1) the 100-year return period snowfall event and (2) the historical maximum snowfall event in the site region.
The extreme liquid winter precipitation event, which is defined as the theoretically greatest depth of precipitation (in inches of water) for a 48-hour period that is
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physically possible over a 25.9-square-kilometer (10-square-mile) area at a particular geographical location during those months with the historically highest snowpacks.
From a probabilistic standpoint, the estimated weight of the 100-year return period ground-level snowpack for the STP site area is 0 lb/ft, as determined in accordance with the guidance in Section C7.0 of the ASCE-SEI design standard, “Minimum Design Loads for Buildings and Other Structures” (Reference 2.3S-10).
Due to temperatures at the surface, the site region is not favorable for snowpack accumulation. In addition, there are not enough available snow observations to calculate a 100-year return snowfall. Therefore, the weight of the historic maximum snowfall event, 10.5 inches at the Danevang 1 W station (Table 2.3S-3), would represent both the normal winter precipitation event and the extreme frozen winter precipitation event. To convert the historical maximum snowfall into a snow load, the following formula was used:
L = S x 5.2 Where:
S is the liquid equivalent (in inches) associated with the maximum snowfall event. Reference 2 presents the observed snowfall at Danevang 1 W station (12/25/2004) of 10.5" and the observed equivalent liquid precipitation of 1.05".
2 5.2 is the weight of one inch of water in lb/ft
Thus, the weight of the normal winter precipitation and extreme frozen winter precipitation would both be
L = 1.05 x 5.2 = 5.5 lb/ft2
The extreme liquid water precipitation [Probable Maximum Winter Precipitation (PMWP)] event at the STP site was determined to be 34.0 inches. The 48-hour PMWP event is derived through logarithmic interpolation of the 48-hour precipitation value from the 6-hr, 24-hr, and 72-hr PMWP values in Hydrometeorological Report No. 53 (Reference 2.3S-11).
The 48-hour PMWP value for evaluating extreme live loads is derived from plots of 6-, 24- and 72-hour, 10-square mile area, monthly probable maximum precipitation (PMP) estimates as presented in NUREG/CR-1486 (Reference 2.3S-11). Based on this information, the month of December represents the worst-case (highest) PMP value, in the STP site area, during the winter season in the 6-hour illustration. The months of January and February represent the worst-case PMP values during the winter season in the 24-hour and 72-hour illustrations. The values for the 6-, 24-, and 72-hour PMP values are 17, 28, and 36 inches, respectively. The 48-hour PMWP value, estimated by logarithmic interpolation on the curve defined by the 6-, 24-, and
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72-hour PMP values is 34.0 inches liquid depth. The weight of this 34.0 inches of water is approximately 177 lbs/ft2.
To account for the worst case freezing precipitation that could occur in combination with the worst case 48-hour PMWP, the weight of the maximum snowfall value is converted to a liquid water equivalent. The maximum snowfall event (10.5 inches), mentioned above, is equal to 1.05 inches of liquid precipitation with a corresponding weight of approximately 5.5 lbs / ft2.
The appropriate combination of freezing precipitation and subsequent liquid precipitation (rainfall) is a factor in determining the structural loading conditions for roof design. The standard ABWR Seismic Category I structures have roofs without parapets, or parapets with scuppers to supplement roof drains so that large inventories of water cannot accumulate. Appendix 3H.6 states that the roof structure of the site- specific Seismic Category I structures (e.g., reactor service water pump houses) are designed without parapets so that excessive ponding of water cannot occur. Therefore, the combination of the worst case freezing precipitation and the 48-hour PMWP will not result in an increase in the roof design loading and therefore will not affect the design of these structures.
2.3S.1.3.5 Hail, Snowstorms, and Ice Storms Frozen precipitation in the STP site area typically occurs in the form of hail, snow, sleet, and freezing rain. The frequency of occurrence of these types of weather events is based on the following two references: 1) the latest version of The Climate Atlas of the United States (Reference 2.3S-13), which has been developed from observations made over the 30-year period of record from 1961 to 1990, and 2) the storm events for Texas (Reference 2.3S-14) based on observations for the period January 1950 to March 2007.
Though hail can occur at any time of the year, and is associated with well-developed thunderstorms, it is observed primarily during the spring and early summer months and least often during the late summer and autumn months. The Climate Atlas of the United States (Reference 2.3S-13) indicates that Matagorda County can expect on average, hail with diameter 0.75 inch or greater one day per year. The adjacent counties of Calhoun, Jackson, Wharton, and Brazoria can also expect hail with diameter 0.75 inch or approximately 1 day per year on average. The occurrence of hailstorms with hail greater than or equal to 1.0 inch in diameter averages less than one day per year in Matagorda County and also in the adjacent counties (Reference 2.3S-13).
NCDC cautions that hailstorm events are point observations and somewhat dependent on population density. Hailstorm events within Matagorda and surrounding counties have generally reported the maximum hail stone diameters between 2.0 and 4.5 inches. The maximum diameter of hail observed in Matagorda County was approximately 2 inches, approximately nine miles south-southeast of the STP 3 & 4. Hailstones having a diameter of approximately 2.5 inches have been reported in Pearland, Texas (Brazoria County), approximately 61 miles northeast of STP 3 & 4. Several nearby counties have reported hail measuring approximately 2.75 inches in diameter. These locations include Granado, Texas (Jackson County), Arcola, Texas
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(Fort Bend County), and Victoria, Texas (Victoria County), which are 33 miles west, 61 miles northeast, and 52 miles west, respectively, from the STP 3 & 4 site. In terms of extreme hailstorm events, the NCDC publication Storm Data indicates that grapefruit size hail (approximately 4.5 inches in diameter) was observed on two occasions at two different locations in the general STP site area, on April 11, 1995, in Calhoun, Texas, in Calhoun County approximately 67 miles north-northwest of the STP site and June 20, 1996 in Egypt, Texas, in Wharton County, approximately 43 miles north-northwest of the STP site (Reference 2.3S-14).
From central Texas southward, most winters bring no accumulation of snowfall. Freak snowstorms occur only once every few decades, but no corner of the state is immune (Reference 2.3S-22). Snow forms if the air temperature in a cloud is below freezing. The water vapor in the cloud turns to ice and tiny ice crystals stick together until they form snowflakes. As the snowflake falls through the cloud, the crystal continues to grow by picking up more water vapor. When they get heavy enough to fall, they drop out of the clouds. If the air temperature on the way down to the ground remains below freezing, then the snowflakes will fall without melting and so fall as snow.
Any accumulation of snow is a rare occurrence on the Upper Coastal division within the Coastal Prairie region where the STP site is located, with normal annual totals at all observing stations averaging less than 0.5 inch. Historical records for the area (see Table 2.3S-3) indicate that maximum 24-hour and monthly snowfalls have occurred during the months of November, December, January, and February (see Table 2.3S- 2). The greatest snowfall on record in the STP area was measured at the Danevang 1W weather observing station located 20 miles north-northwest of the STP site. 24- hour and monthly total station records of 10.5 inches were recorded during the Christmas Storm of 2004 (Reference 2.3S-14). Additional details of maximum 24-hour and cumulative monthly record snowfall totals are given in Subsection 2.3S.1.3.4 and Tables 2.3S-3 and 2.3S-5.
Depending on the temperature characteristics of the air mass, snow events are often accompanied by or alternate between sleet and freezing rain (ice). In most cases, freezing rain results from the process of warm moist air "overrunning" colder air. Freezing rain is caused by rain falling into a relatively shallow layer of cold air with temperatures either at or just below the freezing point (Reference 2.3S-23). Arctic air masses that reach the Upper Coastal division in the winter season are typically very shallow and have been known to produce ice storms. According to the Climatic Atlas (Reference 2.3S-13), freezing precipitation occurs only approximately 2.5 to 5.4 days per year at the STP Site.
An ice storm occurred January 12 - 13, 1997, and impacted the Texas counties of Matagorda, Brazoria, Fort Bend, Jackson, and Wharton. Trees, power lines and roadways were all affected. The weight of the ice caused trees and power lines to fall. Estimated damage was set at $800,000. Another reported winter weather event with sleet, snow and rain mix impacted the counties of Victoria and Calhoun on December 8, 2006. Light ice accumulations were reported on roadways. Widespread ice accumulation on roads, bridges, and the roofing of general structures was reported on
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January 16 - 17, 2007, in nearby Fort Bend and Wharton counties. Property damage was reported to be estimated at $51,000 (Reference 2.3S-14).
Dust and sand storms are short-term meteorological conditions and there have been no reported records of probable annual frequency of dust storms at the STP site area.
2.3S.1.3.6 Thunderstorms and Lightning Thunderstorms can occur in the STP 3 & 4 site area at any time during the year. According to a 43-year period of record, Victoria, Texas, averages approximately 56 thunderstorm-days (i.e., days on which thunder is heard at an observing station) per year. On average, August has the highest monthly frequency of occurrence — approximately 9.7 days. Annually, nearly 45% of thunderstorm-days are recorded during July, August, and September. From November through February, a thunderstorm might be expected to occur approximately one to two days per month (Reference 2.3S-1).
The mean frequency of lightning strokes to earth can be estimated using a method attributed to the Electric Power Research Institute, as reported by the U.S. Department of Agriculture Rural Utilities Service in the 1998 publication titled “Summary of Items of Engineering Interest” (Reference 2.3S-24). This methodology assumes a relationship between the average number of thunderstorm-days per year (T) and the number of lightning strokes to earth per square mile per year (N), where:
N = 0.31T
Based on the average number of thunderstorm-days per year at Victoria (i.e., 56; see Table 2.3S-2) the frequency of lightning strokes to earth per square mile is approximately 17 per year for the site area. This frequency is similar to the mean of the 10 year (1989 to 1999) cloud-to-ground flash density for the area that includes the site for STP 3 & 4, as reported by the NWS, of approximately 7 flashes/km/year or 18 flashes/mi2/year (Reference 2.3S-25).
2.3S.1.4 Meteorological Data for Evaluating the Ultimate Heat Sink As discussed in Subsection 9.2.5, each UHS water storage basin is located partially below grade and is sized for a water volume sufficient to meet the cooling requirements for 30 days following a design basis accident with no makeup water and without exceeding the design basis temperature and chemistry limits. The primary makeup water source is well water, and the backup source is water from the 7000-acre Main Cooling Reservoir (MCR). Makeup water to the MCR is provided from the Colorado River using the existing makeup water system.
Each reactor has a safety-related Reactor Service Water (RSW) system available during all modes of system operation to provide cooling water to the Reactor Building Cooling Water (RCW) system heat exchangers located in the Control Building. Each unit has a counterflow mechanically induced draft cooling tower with six cooling tower cells, of which two cells are dedicated to each of the three RSW divisions to remove heat from their respective RCW/RSW division.
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The UHS thermal performance, design meteorology, conditions that maximize water temperature, and conditions that maximize water usage are presented in FSAR subsection 9.2.5.5 and in Tables 9.2-23a and 9.2-23b. The meteorological data presented in the Tables was developed in accordance with the requirements of Regulatory Guide 1.27, Revision 2 using 45 years of hourly surface weather data from Victoria, Texas. The weather data was analyzed to determine the highest average dry bulb temperature, highest average wet bulb temperature and highest average evaporation potential for 30 consecutive day and 1 day periods using a running average. The evaporation potential is the difference between the moisture content of saturated air at the dry bulb temperature minus the actual moisture content of the air. The UHS thermal performance analysis was then performed using the 3 sets of processed meteorological data with the highest average wet bulb temperature, highest average dry bulb temperature, and highest average evaporation potential as different cases. The results were then evaluated to determine maximum evaporation (30 day data sets) and maximum basin water temperature (1 day data sets). The meteorological conditions summarized in Tables 9.2-23a and 9.2-23b represent the worst-case for evaporation and temperature, respectively.
An evaluation was also performed using a recent 18-year period of sequential data for Palacios, Texas, to determine the effect on UHS performance for comparison to performance using the Victoria data. The results of the evaluation are discussed in Subsection 9.2.5.5.
2.3S.1.5 Design Basis Dry- and Wet-Bulb Temperatures Long-term, engineering-related climatological data summaries, prepared by the ASHRAE from observations at the nearby Palacios Municipal Airport (Reference 2.3S- 9), are used to characterize design basis dry- and wet-bulb temperature conditions representative of the site for STP 3 & 4. These characteristics include:
Maximum ambient threshold dry-bulb temperatures at annual exceedance probabilities of 2.0%, 1.0%, and 0.4%, along with the mean coincident wet-bulb (MCWB) temperatures at those values.
Minimum ambient threshold dry-bulb temperatures at annual exceedance probabilities of 99.0 and 99.6%.
Maximum ambient threshold wet-bulb temperatures at annual exceedance probabilities of 2.0%, 1.0%, and 0.4% (noncoincident).
Based on the 15-year period of record from 1987 to 2001 for Palacios, the maximum dry-bulb temperature with a 2.0% annual exceedance probability is 90.2°F (32.3°C), with a MCWB temperature of 79.2°F (26.2°C). The maximum dry-bulb temperature with a 1.0% annual exceedance probability is 91.0°F (32.8°C), with a corresponding MCWB temperature value of 79.3°F (26.3°C). The maximum dry-bulb temperature with a 0.4% annual exceedance probability is 92.2°F (33.4°C), with a corresponding MCWB temperature value of 79.5°F (26.4°C) (Reference 2.3S-9).
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For the same period of record, the minimum dry-bulb temperatures with 99.6 and 99.0% annual exceedance probabilities are 31.7°F (-0.2°C) and 35.8°F (2.1°C), respectively (Reference 2.3S-9).
The maximum wet-bulb temperatures with 2.0%, 1.0%, and 0.4% annual exceedance probabilities (noncoincident) are 80.5°F (26.9°C), 81.2°F (27.3°C), and 81.9°F (27.7°C), respectively (Reference 2.3S-9).
The data summaries from which the preceding statistical values were obtained do not include values that represent return intervals of 100 years. Maximum dry-bulb, minimum dry-bulb, and maximum wet-bulb temperatures corresponding to a 100-year return period were derived through linear regression using individual daily maximum and minimum dry-bulb temperatures and maximum daily wet-bulb temperatures recorded over a 30-year period, from 1971 to 2000, at the Victoria, Texas, NWS station (References 2.3S-7 and 2.3S-8). Because the 100-year return period dry-bulb temperature values are extrapolated from a regression curve, no corresponding MCWB temperatures are available for this return interval.
Based on the linear regression analyses of the Victoria data sets for a 100-year return period, the 0% exceedance dry-bulb temperature is estimated to be 111.3°F (44°C). The minimum dry-bulb temperature is estimated to be approximately 3.6°F (-15.8°C), and the maximum wet-bulb temperature is estimated to be 86.1°F (30°C).
The maximum and minimum recorded dry-bulb and maximum recorded wet-bulb temperatures as well as the corresponding 100-year return period values are considered. The higher of either the maximum recorded value or the 100-year return period value for either Victoria or Palacios are then determined in order to compare with the ABWR standard plant design parameters. This approach meets the requirements of 10CFR 52.79(a)(1)(iii).
Palacios is located about 13 miles WSW of the proposed site. Unlike Victoria, 30 years of the meteorological data are not available from Palacios; therefore, a shorter period of meteorological data was used to estimate the 100-year return period values. Using the 20-year (1998-2007) Palacios hourly data set (References 2.3S-60 through 2.3S-68), the maximum recorded dry-bulb and coincident wet-bulb temperatures are 106°F and 77.8°F, respectively. The maximum recorded non-coincident wet-bulb temperature was 86.1°F.
Additionally, using a linear regression analysis, the 100-year return period maximum drybulb temperature was estimated to be 108.1°F. The 100-year return period non-coincident wet-bulb temperature was estimated to be 88.3°F. This value is slightly higher than the Victoria 100-year return period non-coincident wet-bulb temperature of 86.1°F. This is expected as Palacios is located closer to the Gulf of Mexico than Victoria.
Based on a comparison of the maximum recorded and 100-year return period values for Victoria and Palacios, the Victoria dry-bulb temperature of 111.3°F is determined as the 0% exceedance dry-bulb temperature for comparison with the corresponding
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DCD value. The wet-bulb temperature coincident with this dry-bulb temperature at Victoria is 72.4°F.
The reference ABWR DCD Tier 1, Table 5.0 and Tier 2, Table 2.0-1 include the following site parameter values for ambient design temperatures, as indicated below, for which the ABWR plant is designed:
0% Exceedance Values (Historical Limit) - Maximum:
– 46.1°C (115°F) dry-bulb, 26.7°C (80.1°F) wet-bulb (coincident)
– 27.2°C (81.0°F) wet-bulb (noncoincident)
0% Exceedance Values (Historical Limit) - Minimum:
– -40°C (-40°F) dry-bulb
1% Exceedance Values - Maximum:
– 37.8°C (100°F) dry-bulb, 25°C (77°F) wet-bulb (coincident)
– 26.7°C (80°F) wet-bulb (noncoincident)
1% Exceedance Value - Minimum:
– -23.3°C (-9.9°F) dry-bulb
The above results indicate that the reference ABWR DCD 1% maximum dry-bulb (100°F) bounds the site-specific (Palacios) value of 91°F. The reference ABWR DCD 0% maximum dry-bulb (115°F) and coincident wet-bulb (80°F) also bounds the site- specific (Victoria) 100-year return dry-bulb (111.3°F) and the coincident wet-bulb (72.4°F). The reference ABWR DCD 1% minimum dry-bulb (-9.9°F) bounds the corresponding site-specific (Palacios) value of 35.8°F. The reference ABWR DCD 0% minimum dry-bulb (-40°F) bounds the corresponding site-specific (Victoria) 100-year return value of 3.6°F. The reference ABWR DCD 1% noncoincident maximum wet - bulb (80°F) and 0% maximum wet-bulb (81°F) do not bound the corresponding site- specific 1% value (81.2°F, Palacios) or the 100-year return value (88.3°F, Palacios), respectively. The maximum dry-bulb in combination with coincident wet-bulb provides the annual cooling, dehumidification, and enthalpy design condition, which is used as input to determine the HVAC system cooling loads. The enthalpy of the air based on STP site-specific conditions is not bounded by the reference ABWR DCD value for 1% exceedance condition. The maximum noncoincident wet-bulb is typically used as input for sizing the cooling towers and evaporative coolers. The 1% maximum coincident and noncoincident wet-bulb temperatures and the 0% maximum noncoincident wet- bulb temperature have been identified as departures to ABWR Tier 1 Table 5, and Tier 2 Table 2.0-1 parameters (see STP DEP T1 5.0-1). As discussed in Table 2.0-2, the slight temperature exceedances from the DCD site parameters have no adverse impact on either the HVAC, or UHS performance as determined in accordance with R.G. 1.27, for STP 3 & 4.
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2.3S.1.6 Restrictive Dispersion Conditions Atmospheric dispersion can be described as the horizontal and vertical transport and diffusion of pollutants released into the atmosphere. Horizontal and along-wind dispersion is controlled primarily by wind direction variation, wind speed, and atmospheric stability. Subsection 2.3S.2.2.1 addresses wind direction characteristics for the STP 3 & 4 site vicinity based on measurements from the existing meteorological monitoring program at STP 1 & 2. The persistence of wind conditions at STP 1 & 2 are discussed in Subsection 2.3S.2.2.2. The seasonal and annual atmospheric stability conditions representative of conditions at STP 3 & 4 are discussed in Subsection 2.3S.2.2.3.
In general, lower wind speeds represent less-turbulent air flow, which restricts horizontal and vertical dispersion. And, although wind direction tends to be more variable under lower wind speed conditions (which increases horizontal transport), air parcels containing pollutants often recirculate within a limited area, thereby increasing cumulative exposure.
Major air pollution episodes are usually related to the presence of stagnating high- pressure weather systems (or anti-cyclones) that influence a region with light and variable wind conditions for four or more consecutive days. An updated air stagnation climatology report entitled Air Stagnation Climatology for the United States (Reference 2.3S-16) has been published with data for the continental US based on over 50 years of observations. In this study, stagnation conditions were defined as four or more consecutive days when meteorological conditions were conducive to poor dispersion. Although inter-annual frequency varies, the data in Figures 1 and 2 of that report indicates that on average, STP 3 & 4 can expect approximately 30 days with stagnation conditions, or about six cases per year, with the mean duration of each case lasting about five days (Reference 2.3S-16).
Air stagnation conditions primarily occur during an “extended” summer season that runs from May through October. This is a result of the weaker pressure and temperature gradients, and therefore weaker wind circulations, during this period (as opposed to the winter season). Based on Wang and Angell, 1999, Figures 17 to 67 (Reference 2.3S-16), the highest incidence is recorded between July and September, typically reaching its peak during August, when the Bermuda High pressure system has become established. As the LCD summary for Victoria, Texas, in Table 2.3S-2 indicates, this 3-month period also coincides with the lowest monthly mean wind speeds during the year. Air stagnation is at a relative minimum within the “extended” summer season during May and June (Reference 2.3S-16).
The dispersion of air pollutants is also a function of the mixing height. The mixing height (or depth) is defined as the height above the surface through which relatively vigorous vertical mixing takes place. Lower mixing heights (and wind speeds), therefore, are a relative indicator of more restrictive dispersion conditions. USDA Forest Service Ventilation Climate Information System (Reference 2.3S-26) reports statistical data for mean monthly morning and afternoon mixing heights and wind speeds for locations in the contiguous U.S., Alaska, and Hawaii. The data used to compute the statistics is based on observations over the periods 1961–1990 for mixing
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heights and 1959–1998 for wind speed. Monthly statistics for these parameters include minimum, maximum, and mean values, average wind direction, and most frequent wind direction and are based on the longitude and latitude of the site location.
Table 2.3S-4 summarizes the mean seasonal and annual morning and afternoon mixing heights and wind speeds for the STP site area. From a climatological perspective, the lowest morning mixing heights occur in the autumn and the highest during spring. As might be expected, the afternoon mixing heights are lowest in the winter and highest in the summer, due to more intense summertime heating.
The wind speeds listed in Table 2.3S-4 for the location of STP 3 & 4 are consistent with the mean seasonal wind speeds summarized in the LCD for Victoria, Texas (see Table 2.3S-2) and the STP onsite data (see Table 2.3S-9) in that the lowest mean wind speeds are shown to occur during the summer and autumn. This period of minimum wind speeds also coincides with the “extended” summer season described by Wang and Angell that is characterized by relatively higher stagnation conditions.
2.3S.1.7 Climate Changes That climatic conditions change over time, and that such changes are cyclical in nature on various time and spatial scales, is a given. The timing, magnitude, relative contributions to, and implications of these changes is generally more speculative, even more so for specific areas or locations.
With regard to the operating life for STP 3 & 4, it is reasonable to evaluate the record of readily-available and well-documented climatological observations of temperature and rainfall (normals, means and extremes) as they have varied over time (i.e., the last 60 to 70 years or so), and the occurrences of severe weather events, in the context of the plant’s design bases.
Trends of temperature and rainfall normals and standard deviations have been identified over a 70-year period for successive 30-year intervals, updated every 10 years, beginning in 1931 (e.g., 1931–1960, 1941–1970, etc.) through the most recent normal period (i.e., 1971–2000) in the NCDC publication Climatography of the United States, No. 85 (Reference 2.3S-17). The publication summarizes observations for the 344 climate divisions in the 48 contiguous states.
A climate division represents a region within a state that is as climatically homogeneous as possible. Division boundaries generally coincide with county boundaries except in the Western U.S. In Texas, the STP site is located within Climate Division Texas-08 (Upper Coast). A summary of successive annual temperature and rainfall normals as well as the composite 70-year average, are provided below for this climate division (Reference 2.3S-17).
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Temperature (°F) Rainfall (inches) Period Texas-08 Texas-08 1931–2000 69.3 47.75 1931–1960 69.5 46.17 1941–1970 69.4 46.41 1951–1980 69.1 45.93 1961–1990 68.9 47.63 1971–2000 69.2 50.31 This data indicate a slight cooling trend over most of the 70-year period with a slight increase of approximately to 0.3°F during the most recent normal period. In general, total annual rainfall decreased slightly up through the 1951 to 1980 normal period and has trended upward by approximately 4.5 inches during the two succeeding 30-year normal periods. Despite the varying climatic regimes that characterize the state of Texas, similar trends in temperature normals and total annual rainfall normals are observable in nearly all of the other climate divisions in the state (Reference 2.3S-17).
The preceding values represent variations of average temperature and rainfall conditions over time. The occurrence of extreme temperature and precipitation (rainfall and snowfall) events do not necessarily follow the same trends. However, the occurrence of such events over time are indicated by the summaries for observed extremes of temperature, rainfall and snowfall totals recorded in the STP site area (see Table 2.3S-3).
The data summarized in Table 2.3S-3 shows that individual station records for maximum temperature have been set between 1954 and 2005 – that is, there is no discernable trend for these extremes in the site area. Similarly, record-setting 24-hour rainfall totals were established between 1911 and 1991; station records for the maximum monthly rainfall have been set between 1945 and 1994—again, no clear trend. Cold air outbreaks that result in overall extreme low temperature records occur infrequently; record-setting snowfalls are even more rare events. The few dates of occurrence between 1940 and 1989, 1940 and 2004, 1940 and 2004, over which minimum temperatures and maximum daily and monthly snowfall totals have been recorded, respectively, are indicative of this characteristic.
Characteristics and/or effects of other types of severe weather phenomena have been discussed previously, including tornados (see Subsection 2.3S.1.3.2) and tropical cyclones (see Subsection 2.3S.1.3.3).
The number of recorded tornado events has increased since detailed records were routinely documented beginning around 1950. However, some of this increase is attributable to a growing population, greater public awareness and interest, and technological advances in detection. These changes are superimposed on normal year-to-year variations.
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The occurrence of all tropical cyclones within a 100-nautical mile radius of the STP site has been somewhat cyclical over the available 155-year period of record when considered on a decadal (i.e., 10-year) basis, having reached a peak of 10 such storms during the 1940s, with a secondary peak of eight tropical cyclone events some 60 years earlier in the 1880’s. Both the frequency and intensity of hurricanes passing within 100 nautical miles of the site have generally decreased since the peak period from 1940 to 1949. The frequency of tropical storms has been fairly steady since the 1960’s, totaling approximately three such storms each decade; this is relatively more frequent than in the decades preceding the peak during the 1940’s. Many of the 24- hour and monthly total rainfall records identified in Table 2.3S-3 and discussed in Subsection 2.3S.1.3.3 are associated with these tropical cyclone events (Reference 2.3S-12).
Nevertheless, the regulatory guidance for evaluating the climatological characteristics of a site from a design basis standpoint is not event-specific, but rather is statistically based and for several parameters includes expected return periods of 100 years or more and probable maximum event concepts. These return periods exceed the design life of the proposed units. The design-basis characteristics determined previously under Subsection 2.3S.1.3 are developed consistent with the intent of that guidance and incorporate the readily-available, historical data records for locations considered to be representative of the site for STP 3 & 4. These site characteristic values are summarized and compared in Table 2.0-2 and in the applicable subsections under Subsection 2.3S.1.3.
2.3S.2 Local Meteorology The following site-specific supplement addresses COL License Information Item 2.9.
This section addresses various meteorological and climatological characteristics of the site and vicinity surrounding STP 3 & 4. FSAR Subsection 2.3S.2.1 identifies data resources used to develop the climatological descriptions and provides information about the onsite meteorological monitoring program used to characterize the site- specific atmospheric dispersion conditions.
Site-specific characteristics related to atmospheric transport and diffusion are discussed in Subsections 2.3S.2.2.1, 2.3S.2.2.2 and 2.3S.2.2.3.
Climatological normals, means and extremes (including temperature, rainfall and snowfall), based on the long-term records from nearby observing stations, are described in Subsections 2.3S.2.2.4 through 2.3S.2.2.7 and evaluated to substantiate that these observations are representative of conditions that might be expected to occur at the site for STP 3 & 4.
Subsection 2.3S.2.3 describes topographic features of the site, as well as in the broader site and surrounding area out to 50 miles. Subsection 2.3S.2.4 addresses the potential influence on these normal, mean and extreme climatological conditions due to the presence and operation of STP 3 & 4 and their related facilities, and those associated with STP 1 & 2.
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Finally, Subsection 2.3S.2.5 discusses current ambient air quality conditions in the site area and region that have a bearing on plant design and operations, describes the types of non-radiological air emission sources at the facility, briefly summarizes expected air quality impacts during facility operations, and identifies related regulations and permits.
2.3S.2.1 Data Sources The primary sources of data used to characterize local meteorological and climatological conditions representative of the site for STP 3 & 4 includes long-term summaries from the first-order NWS station at Victoria, Texas and from 14 other nearby cooperative network observing stations, as well as measurements from the onsite meteorological monitoring program operated in support of STP 1 & 2. Table 2.3S-1 identifies the offsite observing stations and provides the approximate distance and direction of each station relative to the site for STP 3 & 4; their locations are shown in Figure 2.3S-1.
There are several first-order NWS stations located along the western Gulf of Mexico coast (Palacios, Victoria, Corpus Christi and Galveston) that could have long-term (30- year) hourly meteorological data available to describe the general STP site area meteorological and climatological conditions. Galveston and Corpus Christi are located approximately 81 (east-northeast) and 100 miles (southwest) from the STP site, respectively. They are too far from the STP site since the “nearby” stations are defined in Section 2.3.2 of NUREG-0800 (Reference 2.3S-6).
Palacios is located approximately 13 miles to the west-southwest, and Victoria is located approximately 53 miles to the west of the STP site. Based on the climatological data recorded at Palacios and Victoria (Reference 2.3S-2), the monthly mean daily maximum temperatures are slightly higher at Victoria than those measured at Palacios; and the monthly mean daily minimum temperatures at Victoria are slightly lower than those measured for Palacios. To be conservative, Victoria data was used to describe the site extreme climatology. In addition, consecutive hourly meteorological data is not available at Palacios during the period of March 1959 through December 1999 (Reference 2.3S-27). Although the Victoria station is located 53 miles from the STP site (slightly longer than the distance defined by NUREG-0800 (Reference 2.3S-6) as “nearby”), the terrain between the STP site and the Victoria station is relatively flat. Additionally, the Victoria station is located at almost the same latitude as the STP site. Therefore, the long-term (30 years) data from the Victoria station was used to describe the general climatic conditions at the STP site.
The locations of the existing onsite primary and backup meteorological towers with respect to STP 1 & 2 and the STP 3 & 4 are shown in Figure 2.3S-15. The primary tower is located approximately 2.1 kilometers (1.3 miles) east of STP 3 & 4, and the backup tower is located approximately 670.5 meters (2200 ft) south of the primary tower. Both locations are clear of man-made and natural obstructions which could influence the collection of meteorological data. Detailed information regarding the meteorological monitoring program for STP 1 & 2 is provided in Subsection 2.3S.3.3.
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The first-order NWS station and cooperative observing station summaries were used to characterize climatological normals (i.e., 30-year averages), and period-of-record means and extremes of temperature, rainfall, and snowfall in the vicinity of STP 3 & 4. In addition, first-order NWS stations record measurements, typically on an hourly basis, of other weather elements, including winds, relative humidity, dew point, and wet-bulb temperatures, as well as other observations (e.g., fog, thunderstorms). This information was based on the following resources (References 2.3S-13, 2.3S-3, 2.3S- 2, 2.3S-4, and 2.3S-5).
Wind direction, wind speed, and atmospheric stability data obtained from the meteorological monitoring program operated in support of STP 1 & 2 forms the basis for determining and characterizing atmospheric dispersion conditions in the vicinity of the site.
RG 1.23 (Reference 2.3S-28) specifically states that the minimum amount of onsite meteorological data to be provided at the time of a COL application that does not reference an Early Site Permit is a consecutive 24-month period of data that is defendable, representative, and complete, but not older than 10 years from the date of the application. Adequacy and accuracy of the STP 1 & 2 meteorological measuring systems were assessed based on NUREG-1555, Standard Review Plans for Environmental Reviews for Nuclear Power Plants (Reference 2.3S-29). The findings conclude that the instrument heights and locations, system accuracies, methodologies for data acquisition and reduction, as well as procedures for instrumentation surveillance conform to the applicable guidance provided in RG 1.23 (Reference 2.3S- 28). Therefore, data collected by the existing STP 1 & 2 meteorological monitoring systems provides a suitable data set for STP 3 & 4. Further information regarding the STP meteorological monitoring systems is presented in Subsection 2.3S.3.
A consecutive 24-month period (1999-2000) of data was identified to be the most defendable (using validated data with the least data substitution), representative (tower siting and sensor location in accordance with RG 1.23), and complete (with annual data recovery rate greater than 90%), but not older than 10 years from the date of the application. Since three or more years of data are RG 1.23 (Reference 2.3S-28) preference, three years (1997, 1999 and 2000) of the STP 1 & 2 data is used in this application.
2.3S.2.2 Normal, Mean, and Extreme Values of Meteorological Parameters Meteorological data obtained from the monitoring program operated in support of STP 1 & 2 is used to characterize atmospheric transport and diffusion conditions in the vicinity of the site for STP 3 & 4. Details regarding these wind and atmospheric stability characteristics are described in Subsections 2.3S.2.2.1 through 2.3S.2.2.3. This site- specific data also provide input to dispersion modeling analyses of onsite and offsite impacts due to accidental and routine radiological releases to the atmosphere (see Subsections 2.3S.4.2 and 2.3S.5, respectively), and at Control Room air intakes and ingress/egress points under accident conditions (see Subsection 2.3S.4.2).
Subsection 2.3S.2.2 also provides summaries of normals, period-of-record means and period-of-record extremes for several standard weather elements – that is,
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temperature, atmospheric water vapor, precipitation, and fog (see FSAR Subsections 2.3S.2.2.4 through 2.3S.2.2.7, respectively).
The normals, means, and extremes of the more extensive set of measurements and observations made at the Victoria, Texas first-order NWS station are summarized in Table 2.3S-2. Table 2.3S-5 compares the annual normal daily maximum, minimum, and mean temperatures, as well as the normal annual rainfall and snowfall totals for these stations. Historical extremes of temperature, rainfall and snowfall are listed in Table 2.3S-3 for the NWS and cooperative observing stations in the STP site area.
2.3S.2.2.1 Average Wind Direction and Wind Speed Conditions The distribution of wind direction and wind speed is an important consideration when characterizing the dispersion climatology of a site. Long-term average wind motions at the macro- and synoptic scales (i.e., on the order of several thousand down to several hundred kilometers) are influenced by the general circulation patterns of the atmosphere at the macro-scale and by large-scale topographic features (e.g., land- water interfaces such as coastal areas). These characteristics are addressed in Subsection 2.3S.1.2.
Site-specific or micro-scale (i.e., 2 km or less) wind conditions, while they may reflect these larger-scale circulation effects, are influenced primarily by local and, generally, to a lesser extent, by meso- or regional-scale (i.e., up to about 200 km) topographic features. Wind measurements at these smaller scales are currently available from the meteorological monitoring program operated in support of STP 1 & 2 and from long- term data recorded at the nearby Victoria, Texas NWS station and shorter-term measurements at the cooperative observation station at Palacios Municipal Airport. Subsection 2.3S.3.3 presents a summary description of the STP onsite monitoring program. In its current configuration, wind direction and wind speed measurements are made at two levels (10-m and 60-m) on an instrumented 60-m guyed tower.
Figures 2.3S-2 through 2.3S-6 present annual and seasonal wind rose plots. Wind rose plots are graphical distributions of the direction from which the wind is blowing and wind speeds for each of sixteen, 22.5° compass sectors centered on north, north- northeast, northeast, etc. for the 10-meter level based on measurements over the composite 3-year period of record that includes calendar years 1997, 1999, and 2000.
The wind direction distribution at the 10-meter level generally follows a southeast orientation on an annual basis (see Figure 2.3S-2). The prevailing wind (i.e., defined as the direction from which the wind blows most often) is from the south-southeast, with nearly 40% of the winds blowing from the southeast through south sectors.
During the winter months (i.e., December through February), north winds prevail, although a bimodal directional distribution is exhibited. Northerly winds (i.e., from the north-northwest through the north-northeast sectors) occur with about the same frequency as winds from the southeast through the south sectors (28 percent of the time) for each group of sectors (see Figure 2.3S-3). The prevalence of northerly winds during the winter season is attributable to increased cold frontal passages as continental, polar air masses intrude the region. Winds from the southeast quadrant
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predominate during the spring and summer with prevailing seasonal directions shifting from the southeast to the south, respectively, as spring moves into summer (see Figures 2.S3-4 and 2.3S-5). The autumn months (i.e., September through November) represent a transitional period that is predominated by winds from the southeast and northeast quadrants (see Figure 2.3S-6). Wind directions with a westerly component are relatively infrequent until late in the autumn and early in the winter. Plots of individual monthly wind roses at the 10-meter measurement level are presented in Figure 2.3S-7.
Wind rose plots based on measurements at the 60-meter measurement level are shown in Figures 2.3S-8 through 2.3S-13. The wind direction distributions for the 60- meter level are fairly similar to the 10-meter level wind roses on a composite annual (see Figure 2.3S-8) and seasonal basis (see Figures 2.3S-9 through 2.3S-12). Plots of individual monthly wind roses at the 60-meter measurement level are presented in Figure 2.3S-13.
Wind information summarized in the Local Climatological Data (LCD) for the Victoria, Texas NWS station (Table 2.3S-2) over a 25-year period of record indicates a prevailing south-southeasterly wind direction (Reference 2.3S-1) that appears to be similar to the 10-m level wind flow at the STP site, at least on an annual basis (see Figure 2.3S-2). The monthly variation of prevailing wind directions for the Victoria station follows a similar pattern from March through August and November and December, but differs during September, October, January and February. However, the variations for the months of September, October, January and February are most likely due to the much shorter period of record for the STP meteorological data, as compared to Victoria station (Reference 2.3S-1).
Based on the 5-year period of record from 1995 through 1999, wind direction measurements from the cooperative observing station at the Palacios Municipal Airport (Reference 2.3S-27) show reasonably similar characteristics in predominant directions on an annual basis. At both locations, reasonably similar variations in the predominant wind direction sectors over the course of the year are also evident.
Table 2.3S-6 summarizes seasonal and annual mean wind speeds based on measurements from the upper and lower levels of the meteorological tower operated in support of STP 1 & 2, over the composite 3-year period, and from wind instrumentation at the Victoria station (28-year mean) (Reference 2.3S-1). The elevation of the wind instruments at the Victoria station is nominally 20 feet (about 6.1 meter) (Reference 2.3S-1), and are comparable to the lower (10-meter) level measurements at the STP site.
On an annual basis, mean wind speeds at the 10- and 60-meter levels are 4.1 m/sec and 6.0 m/sec, respectively, at the STP site. The annual mean wind speed at Victoria (i.e., 4.3 m/sec) is similar to the 10-meter level at the STP site, differing by only 0.2 m/sec; seasonal average wind speeds at Victoria are likewise slightly higher. Seasonal mean wind speeds for both measurement levels at the STP site follow the same pattern discussed in Subsection 2.3S.1.6 with respect to the seasonal variation of relatively higher air stagnation and restrictive dispersion conditions in the site region.
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Mean wind speeds at Palacios for the 5-year period from 1995 through 1999 are similar, although somewhat higher, throughout the year compared to the lower-level, seasonal and annual wind speeds at the STP site and the Victoria NWS station as summarized in Table 2.3S-6. Mean wind speeds are higher by less than 1.0 m/sec on an annual basis, ranging from 0.4 to 1.3 m/sec higher depending on season and measurement location.
Specific differences in directional frequencies and mean wind speeds may be due to station siting and instrumentation, and to different periods of record among the three stations. Nevertheless, the wind direction and wind speed data show reasonable intermediate-field (Palacios) and far-field (Victoria) similarity to the wind conditions measured at the STP site.
There were no occurrences of calm wind conditions (less than 0.27 m/sec) at the STP site over the 3-year period of record that includes calendar years 1997, 1999, and 2000 at either the 10- or 60-meter levels. This is due primarily to the fact that the STP site is a relatively high wind site with annual mean wind speeds of 4.1 and 6.0 m/sec at the lower and upper measurement levels, respectively (see Table 2.3S-6), and because of a starting threshold wind speed of 0.6 mph for the cup-type anemometers in place at the time (see Table 2.3S-15).
2.3S.2.2.2 Wind Direction Persistence Wind direction persistence is a relative indicator of the duration of atmospheric transport from a specific sector-width to a corresponding downwind sector-width that is 180° opposite. Atmospheric dilution is directly proportional to the wind speed (other factors remaining constant). When combined with wind speed, a wind direction persistence/wind speed distribution further indicates the downwind sectors with relatively more or less dilution potential (i.e., higher or lower wind speeds, respectively) associated with a given transport wind direction.
Tables 2.3S-7 and 2.3S-8 present wind direction persistence/wind speed distributions based on measurements at the STP site for the 3-year, preoperational period of record that includes calendar years 1997, 1999, and 2000. The distributions account for durations ranging from 1 to 48 consecutive hours for wind directions from 22.5° upwind sectors centered on each of the 16 standard compass radials (i.e., north, north- northeast, northeast, etc.), and for wind speed groups greater than or equal to 5, 10, 15, 20, 25, and 30 mph. Distributions are provided for wind measurements made at the lower (10-meter) and the upper (60-meter) tower levels, respectively.
Wind direction persistence hours as listed in Table 2.3S-7 are the lower limits within the ranges. At the 10-m level, the longest persistence period is 30 to 36 hours for winds from the southeast sector. This duration appears only in the lowest two wind speed groups (i.e., for wind speeds greater than or equal to 5 mph and 10 mph). Persistence periods of 24 to 30 hours for winds greater than or equal to 5 mph are indicated for several direction sectors, including winds from the east, south-southeast, southeast, south, west-southwest, and north-northwest. For wind speeds greater than or equal to 20 mph, maximum persistence periods are limited to 8 to 12 hours.
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Wind direction persistence hours as listed in Table 2.3S-8 are the lower limits within the ranges. At the 60-meter level, the longest persistence period is 30 to 36 hours, and occurred for two different sectors (i.e., winds from the north and east-northeast). This duration appears only in the lowest two wind speed groups for the north and east- northeast sectors and for the lowest three wind speed groups for the east-northeast sector (i.e., for wind speeds greater than or equal to 5, 10, and 15 mph). Persistence periods of 24 to 30 hours are indicated for multiple direction sectors for the lowest three wind speed groups. For wind speeds greater than or equal to 25 mph, maximum persistence periods are limited to 8 to 12 hours with the exception of one 12 to 18 hour duration from the south sector.
2.3S.2.2.3 Atmospheric Stability Atmospheric stability is a relative indicator of the potential diffusion of pollutants released into the ambient air. Atmospheric stability is based on the delta-temperature (ΔT) method defined in Table 1 of RG 1.23 (Reference 2.3S-28). The approach classifies stability based on the temperature change with height (i.e., the difference in °C/100 meter). The diffusion capacity is greatest for extremely unstable conditions and decreases progressively through the remaining unstable, neutral stability, and stable classifications.
The diffusion capacity is greatest for extremely unstable conditions and decreases progressively through the remaining unstable, neutral stability, and stable classifications.
During the 3-year period of record, ΔT was determined from the difference between temperature measurements made at the 60- and 10-meter tower levels. Seasonal and annual frequencies of atmospheric stability class and associated 10-meter level mean wind speeds for this period of record are presented in Table 2.3S-9.
The data indicates a predominance of neutral stability (Class D) and slightly stable (Class E) conditions throughout the year, ranging from approximately 45% of the time during the autumn to approximately 63% of the time during the winter and spring. Extremely unstable conditions (Class A) occur approximately 14% of the time on an annual basis and are most frequent during the summer and occur least often during the winter months owing, in large part, to greater and lesser insolation, respectively, and relatively lower and higher mean wind speeds, respectively. Extremely and moderately stable conditions (Classes G and F, respectively) are most frequent during autumn (approximately 30% of the time) and winter (approximately 20% of the time), owing in part to increased radiational cooling at night. The relatively lower percentage occurrences of stability classes B and C are believed to be due, in part, to the narrow ΔT ranges associated with those classifications (Reference 2.3S-28).
Joint frequency distributions (JFDs) of wind speed and wind direction by atmospheric stability class and for all stability classes combined for the 10-meter and 60-meter wind measurement levels at the STP site are presented in Tables 2.3S-10 and Table 2.3S- 11, respectively, for the 3-year period of record. The 10-meter level JFDs are used to evaluate short-term dispersion estimates for accidental atmospheric releases (see
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Subsection 2.3S.4) and long-term diffusion estimates for routine releases to the atmosphere (see Subsection 2.3S.5).
2.3S.2.2.4 Temperature Daily mean temperatures are based on the average of the daily mean maximum and daily mean minimum temperature values. Normal annual daily mean temperatures are similar over the site area, ranging from 68.8°F at the Danevang 1W observing station to 71.1°F at the Point Comfort observing station (see Table 2.3S-5), which are separated by a distance of approximately 33 miles. Diurnal (day-to-night) temperature ranges, as indicated by the differences between the daily mean maximum and minimum temperatures, however, are more variable, ranging from 11.4°F at Port O’Connor to 21.7°F at the Pierce 1E station (Reference 2.3S-3). In general, the greater diurnal temperature ranges among the one NWS and 14 nearby cooperative observer stations occur at those stations farther from the Gulf of Mexico and adjacent bays, and are less for those stations closer to those waters (Figure 2.3S-1).
As Table 2.3S-3 indicates, extreme maximum temperatures recorded in the vicinity of the STP site have ranged from 102°F to 112°F, with the highest reading observed at the cooperative observing station at Pierce 1E on September 5, 2000. The record high temperatures for the Bay City Waterworks (109°F), Danevang 1W (109°F), Freeport 2NW (105°F), and Aransas Wildlife Refuge (102°F) observing stations have been reached on two or three occasions. Extreme minimum temperatures in the vicinity of the site for STP 3 & 4 have ranged from 4°F to 13°F, with the lowest reading on record observed at the Pierce 1E observing station on January 31, 1949 (References 2.3S-2, 2.3S-4, and 2.3S-20).
The extreme maximum and minimum temperature data, and the historical station records on which it is based, indicates that synoptic-scale conditions responsible for periods of record-setting excessive heat as well as significant cold air outbreaks tend to affect the overall STP site area (References 2.3S-2, 2.3S-4, and 2.3S-20). The general similarity of the respective extremes suggests that these statistics are representative of the site area. However, as with the variation in the station diurnal temperature ranges noted above, proximity to the water has a moderating influence on extreme maximum and minimum temperatures. Therefore, extreme temperature characteristics at the site for STP 3 & 4 will likely be within the range of maximum and minimum records reported in Table 2.3S-3 for the climatological observing stations located farther inland.
2.3S.2.2.5 Atmospheric Water Vapor Based on a 20-year period of record, the LCD summary for the Victoria, Texas NWS station (see Table 2.3S-2) indicates that the mean annual wet-bulb temperature is 64.5°F, with a seasonal maximum during the summer months (June through August) and a seasonal minimum during the winter months (December through February). The highest monthly mean wet-bulb temperature is 76.2°F in July (and virtually the same during August); the lowest monthly mean value (50.0°F) occurs during January (Reference 2.3S-1).
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The LCD summary shows a mean annual dew point temperature of 60.9°F, also reaching its seasonal maximum and minimum during the summer and winter, respectively. The highest monthly mean dew point temperature is 73.1°F, reaching its peak in July and August. The lowest monthly mean dew point temperature (46.0°F) occurs during January (Reference 2.3S-1).
The 30-year normal daily relative humidity averages 76% on an annual basis, typically reaching its diurnal maximum in the early morning (around 0600 hours) and its diurnal minimum during the mid-day (around 1200 hours). There is less variability in this daily pattern with the passage of weather systems, persistent cloud cover, and precipitation. Nevertheless, this daily pattern is evident throughout the year. The LCD summary shows that average early morning relative humidity levels are greater than or equal to 90% from May through November and are not much lower during the remaining months of the year (Reference 2.3S-1).
As discussed in FSAR Section 2.3S.1.5, due to the proximity of Palacios to the STP site, water vapor data from Palacios are also presented in this section. Using 20 years (1998-2007) of continuous hourly Palacios meteorological data obtained from National Climatological Data Center (References 2.3S-60-68), the 100-year return period noncoincident wet bulb temperature was estimated to be 88.3°F.
The mean annual wet bulb temperature is 66.3°F at Palacios (Reference 2.3S-69). This is slightly higher than that found at Victoria (64.5°F). The slight increase in wet- bulb temperature is expected as Palacios is located closer to Gulf of Mexico than Victoria. The 20-year data shows the mean annual dew point temperature is 63.2°F at Palacios (Reference 2.3S-69). As expected, this value is also slightly higher than that value at Victoria (60.9°F).
The Palacios 20-year annual average relative humidity is 80% (Reference 2.3S-69). Because the proximity to the Gulf of Mexico, it is higher than that found at Victoria (76%).
2.3S.2.2.6 Precipitation As Table 2.3S-5 indicates, normal annual rainfall totals vary substantially, ranging from 34.78 inches at the Port O’Connor observing station to 57.24 inches at the Angleton 2W observing station (Reference 2.3S-3). This data, in conjunction with Figure 2.3S- 1, also indicate that total annual rainfall tends to decrease more from east to west more than as a function of distance inland from the Gulf of Mexico and adjacent bay waters.
However, when the four climatological observing stations closest to, and surrounding, STP 3 & 4 are considered (i.e., Matagorda 2, Palacios Municipal Airport, Bay City Waterworks, and Danevang 1W), all within 20 miles, normal annual rainfall totals are quite similar, ranging from 43.75 inches at Matagorda 2 to 48.03 inches at Bay City Waterworks (Reference 2.3S-3). Therefore, long-term average annual total rainfall at STP 3 & 4 could reasonably be expected to be within this range.
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Measurable snowfall occurs only rarely in the STP 3 & 4 site area, as discussed in Subsection 2.3S.1.3.4, with normal annual totals at all observing stations averaging less than 0.3 inches (Reference 2.3S-2).
2.3S.2.2.7 Fog The closest station to the STP site at which observations of fog are made and routinely recorded is the Victoria, Texas NWS station approximately 53 miles to the west. The NWS defines heavy fog as fog that reduces visibility to ¼ mi or less. The 2005 LCD summary for this station (Table 2.3S-2) indicates an average of 41.7 days per year of heavy fog conditions, based on a 43-year period of record (Reference 2.3S-1).
On average, the occurrence of heavy fog conditions follows a cyclical pattern over the course of the year, being recorded most often from November through March when normal daily minimum temperatures are relatively lower. The peak frequency is reached during January, averaging approximately seven days per month. Heavy fog occurs least often during the summer (June, July and August), averaging less than one day per month in each of those months.
2.3S.2.3 Topographic Description The STP 3 & 4 site is located in Matagorda County, Texas, approximately 12 miles SSW of the city limits of Bay City, Texas, and 10 miles north of Matagorda Bay. The terrain elevation at the site is approximately 25 feet above MSL.
Topographic features within a 50-mile (80-kilometer) radius of the STP site, based on digital map elevations, are shown in Figure 2.3S-14 The terrain in the site area is basically flat to the northeast and southwest of the site, decreases to sea level to the south and southeast as the Gulf of Mexico and adjacent bay waters are reached, and increases gradually in the northwest quadrant relative to the site to a maximum elevation of about 165 feet (about 50 meters) above MSL within this radial area.
More detailed topographic features within a 5-mile (8-kilometer) radius of the STP site, also based on digital map elevations, are shown in Figure 2.3S-15, including elevation characteristics in the immediate vicinity of STP 3 & 4.
Terrain elevation profiles along each of the 16 standard 22.5° compass radials out to a distance of 50 miles (80 kilometers) from the site are illustrated in Figure 2.3S-16. Because STP 3 & 4 are located relatively close to one another and because of the distance covered by these profiles, the locus of these radial lines is the center point between the STP 3 & 4 reactor buildings.
2.3S.2.4 Potential Influence of the Plant and Related Facilities on Meteorology The dimensions and operating characteristics of STP 3 & 4, and the STP 1 & 2, and the associated paved, concrete, or other improved surfaces are considered to be insufficient for generating discernible, long-term effects to local- or micro-scale meteorological conditions.
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Wind flow will be altered in areas immediately adjacent to and downwind from larger site structures. However, these effects will likely dissipate within ten structure heights downwind of the intervening structure(s) (Reference 2.3S-28). Similarly, while ambient temperatures immediately above any improved surfaces could increase, these temperature effects will be too limited in their vertical profile and horizontal extent to alter local-, area-, or regional-scale ambient temperature patterns.
While there will be site clearing, grubbing, excavation, leveling, and landscaping activities associated with the construction of STP 3 & 4, these alterations to the existing site terrain will be localized and will not represent a significant change to the gently rolling topographic character of the site vicinity or the surrounding site area. Neither the mean and extreme climatological characteristics of the site area nor the meteorological characteristics of the site and vicinity will be affected as a result of plant construction.
STP 1 & 2 use the main cooling reservoir (MCR) as a means of heat dissipation. Under normal operation, STP 3 & 4 will use a Circulating Water System (CWS) to dissipate waste heat rejected from the main condenser. The CWS will use the existing 7000- acre Main Cooling Reservoir (MCR) for heat dissipation. As discussed in Subsection 9.2.5, each new unit will also have an Ultimate Heat Sink (UHS) to remove heat load from the Reactor Service Water (RSW) System. Each new unit has a counterflow mechanically induced draft cooling tower with six cooling tower cells, of which two cells are dedicated to each of the three RSW divisions to remove heat from their respective RCW/RSW division.
Potential meteorological effects due to the operation of the MCR and these cooling towers may include enhanced ground-level fogging and icing, cloud shadowing and precipitation enhancement, and increased ground-level humidity. These effects and other potential, related environmental impacts (e.g., solids deposition, visible plume formation, transport, and extent) are addressed below and in ER Subsections 5.3.3.1 and 5.3.3.2.
Reactor Service Water System The effects of added salt and moisture from the RSW system were determined using the Seasonal/Annual Cooling Tower Impact (SACTI) model.
The STP Unit 3 & 4 reactor service water (RSW) system was modeled as two towers with a maximum drift rate of 0.005%. Site-specific meteorological data acquired from the STP 1 & 2 meteorological tower for 1997, 1999 and 2000 was used as input for the code. The site-specific data included the wind speed, wind direction, and dry bulb temperature. Additional meteorological data required for the SACTI analysis was acquired from the National Weather Service for the Palacios Municipal Airport Weather Station, also for the years 1997, 1999, and 2000. This data included the total sky clearness value, the dew point temperature, and the ceiling height. The site dry bulb temperature and the Palacios Municipal Airport dew point temperature were used to calculate the wet bulb temperature and the relative humidity.
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For the SACTI model, the towers were assumed to be operating during emergency reactor shutdown where the towers are running at full capacity. Under normal operating conditions the RSW system will operate at only half capacity. Sodium concentration of the makeup water is discussed in COLA Part 3 Environmental Report (ER) Section 2.3.1 and it was assumed that all sodium would be associated with chloride for a corresponding NaCl concentration.
Salt Deposition:
The Unit 4 transformers are located approximately 380 meters north northwest of the Ultimate Heat Sink (UHS). Maximum salt deposition rates at this location are predicted by SACTI to be between 4165 Kg/ (Km2-Mo.) (at 300 meters) and 1139 Kg/ (Km2-Mo.) (at 400 meters). This represents medium to heavy contamination levels over the course of a month according to IEEE Standard C57.19.100-1995 (Reference 1). Since the model assumes that the RSW system will be running at full capacity, when in reality it is expected to run closer to half capacity, actual salt deposition rates are expected to be lower. Natural wash off from rain, which SACTI does not consider, is expected to further decrease these values. The Unit 4 transformers are considered bounding for electrical equipment and transmission lines because they are positioned to receive the greatest amount of salt deposition, as predicted by the SACTI model.
Moisture:
The SACTI model predicts a maximum of zero hours of fogging annually in any location and zero hours seasonally.
Temperature:
As discussed in Section 9.4 of the ABWR DCD, safety-related HVAC systems are designed for an outdoor summer temperature of 115°F. The temperature of the exhaust plume from the UHS will not exceed the RSW return water temperature of 109.4°F, which is below the 115°F outdoor summer temperature. Therefore, added heat from the UHS will not have adverse effects on the HVAC systems.
Main Cooling Reservoir The SACTI model is used to analyze cooling towers; therefore, the code was not considered when addressing potential effects from the MCR.
Salt Deposition:
Any salt deposits on the HVAC systems and electrical equipment from the MCR will be a result of evaporation of the cooling water. Since there is no exit velocity from the evaporative process as in a cooling tower, most of the salt content will remain in the pond. Therefore, salt deposits on HVAC intakes, transmission lines and other electrical equipment as a result of evaporation from the MCR is not expected to affect these plant components.
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Moisture:
The additional water flow from STP Units 3 & 4 to the MCR will increase ambient moisture as a result of raised pond temperatures and evaporation. Although additional fogging may result from the UHS cooling tower plume, the MCR was designed for four units and the HVAC intakes, transmission lines and onsite electrical equipment are designed for outdoor operation, which include environmental conditions such as fog and rain. Thus, no adverse effects to these plant features are expected. Furthermore, HVAC systems are designed to regulate relative humidity which will further mitigate any potential effects.
Temperature:
As discussed above, safety-related HVAC systems are designed for an outdoor summer temperature of 115°F. The analysis described in COLA Part 3, Environmental Report (ER) Table 3.4-3 shows the maximum predicted monthly MCR temperature at the Circulating Water System (CWS) discharge for 4-unit operation from 2003-2005 is 112.3°F. As discussed in ER Section 3.4.2.4, the design MCR intake temperature for STP 3 & 4 is 100°F. Since both the intake design temperature and maximum monthly overall CWS discharge are lower than the outdoor HVAC design temperature, added heat from the MCR is not expected to adversely affect the HVAC systems. Furthermore, since the design basin temperatures for the UHS are lower than that of the MCR intake temperature values, combined temperature effects from the UHS and the MCR will be similar to those from the MCR.
Subsections 2.3S.3.4.1, 2.3S.3.4.2, and 2.3S.3.4.3 provide additional details regarding the considerations made in siting and equipping the meteorological towers in support of STP 3 & 4 in relation to the construction of, and/or major structures associated with, those units.
2.3S.2.5 Current and Projected Site Air Quality This section addresses current ambient air quality conditions in the site area and region that could have a bearing on plant design, construction, and operating basis considerations (Subsection 2.3S.2.5.1). This section also cross-references other sections of this FSAR that address the types and characteristics of non-radiological emission sources associated with plant construction and operation, and the expected impacts associated with those activities, (Subsection 2.3S.2.5.2), and characterizes climatological conditions in the site area and region that may be restrictive to atmospheric dispersion (Subsection 2.3S.1.6).
2.3S.2.5.1 Current Air Quality Conditions STP 3 & 4 are located within the Metropolitan Houston-Galveston Intrastate Air Quality Control Region and includes Matagorda, Austin, Brazoria, Chambers, Colorado, Fort Bend, Galveston, Harris, Liberty, Montgomery, Walker, Waller, and Wharton Counties (Reference 2.3S-30). The STP site is located in Matagorda County. Attainment areas are areas where the ambient levels of criteria air pollutants are designated as being “better than,” “unclassifiable/attainment,” or “cannot be classified or better than” the
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Environmental Protection Agency-promulgated National Ambient Air Quality Standards (Reference 2.3S-31). Criteria pollutants are those for which National Ambient Air Quality Standards have been established: sulfur dioxide; particulate matter (i.e., PM10 and PM2.5 — particles with nominal aerodynamic diameters less than or equal to 10.0 and 2.5 microns, respectively); carbon monoxide; nitrogen dioxide; ozone; and lead (Reference 2.3S-31).
The Metropolitan Houston-Galveston Intrastate Air Quality Control Region (AQCR 216) is in attainment for all criteria pollutants with the exception of the 8-hour ozone standard in Brazoria, Chambers, Fort Bend, Galveston, Harris, Liberty, Montgomery, and Waller counties and for lead. The EPA has granted a request from the Governor of the State of Texas to reclassify the ozone nonattainment status in Brazoria, Chambers, Fort Bend, Galveston, Harris, Liberty, Montgomery, and Waller counties as severe (73 CR 56983, October 1, 2008, Reference 2.3S-55). The attainment status for lead has not been designated for any county in AQCR 216 (Reference 2.3S-56). All of these counties are located either northeast or north-northeast of Matagorda County, with the closest being Brazoria County directly northeast.
Three pristine areas in the states of Texas and Louisiana with Class 1 Areas are designated as “Mandatory Class I Federal Areas Where Visibility is an Important Value.” They include: Big Bend and Guadalupe Mountains National Parks in Texas (Reference 2.3S-33) and the Breton Wilderness Area in Louisiana (Reference 2.3S- 34). The Big Bend National Park is the closest of these Class I areas; about 432 miles west of the STP site. The Breton Wilderness Area and Guadalupe Mountains National Parks are located approximately 442 miles east-northeast and 564 miles west- northwest, respectively, from the STP site.
2.3S.2.5.2 Projected Site Air Quality Conditions The new nuclear steam supply system and other related radiological systems are not sources of criteria pollutants or other air toxics emissions. Supporting equipment (e.g., emergency diesel generators, fire pump engines, combustion turbine) and other non- radiological emission-generating sources (e.g., storage tanks) or activities are not expected to be a significant source of criteria pollutant emissions especially with respect to ozone-precursor emissions (e.g., CO, NOx and volatile organic compounds) in light of the non-attainment status for the 8-hour average ozone NAAQS in nearby Brazoria, Chambers, Fort Bend, Galveston, Harris, Liberty, Montgomery, and Waller Counties.
Supporting equipment will only be operated on an intermittent test or emergency-use basis. Therefore, these emission sources will not be expected to impact ambient air quality levels in the vicinity of STP 3 & 4, nor within the 8-hour average ozone moderate non-attainment area in nearby Brazoria, Chambers, Fort Bend, Galveston, Harris, Liberty, Montgomery, and Waller Counties. Likewise, because of the relatively long distance of separation from STP 3 & 4, visibility at any of the identified Class I Federal Areas will not be expected to be significantly impacted by project construction or facility operations.
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Nevertheless, these non-radiological emission sources will be regulated by the Texas Commission on Environmental Quality (TCEQ) as required under Code of Federal Regulations, Title 30, Part 1, Chapters 101 through 122 depending on the source type, source emissions, and permitting requirements for construction and operation. Currently, STP 1 & 2 are covered by a Federal (Title V) operating permit. The Title V permit is a legally enforceable document that the TCEQ issues to certain air pollution sources after the source has begun to operate, for the purpose of reducing violations of air pollution laws and improving enforcement of those laws. In the case of STP 1 & 2, the Title V permit was renewed on January 25, 2006 and is valid until January 25, 2011 (Reference 2.3S-35). In addition, STP 1 & 2 has been issued a standard exemption or permit by rule for backup emergency generators. Under the permit by rule regulation, the maximum annual operating hours for the backup emergency generator shall not exceed 10% of the normal annual operating schedule of the primary equipment.
2.3S.3 Onsite Meteorological Measurements Program The following site-specific supplement addresses COL License Information Item 2.10.
This section provides a discussion of the preoperational and operational meteorological monitoring programs for STP 3 & 4, including a description and site map showing tower locations with respect to manmade structures, topographic features, and other site features that can influence site meteorological measurements. In addition, a description of measurements made, including elevations and exposure of instruments; instruments used, including instrument performance specifications, calibration and maintenance procedures; data output and recording systems and locations; and data processing, archiving, and analysis procedures is provided (Reference 2.3S-36).
The STP 3 & 4 meteorological monitoring program consists of two phases:
Preoperational Monitoring – Because of the proximity of STP 1 & 2, data collected by the STP 1 & 2 meteorological towers during 1997, 1999, and 2000 has been used to establish a baseline for identifying and assessing environmental impacts resulting from operation of STP 3 & 4. Additional relative humidity/temperature instrumentation at 10 and 60 meters were added in 2006 to baseline moisture content in the environment for a range of mechanical draft cooling towers to be considered for STP 3 & 4.
Operational Monitoring – The current meteorological monitoring program for STP 1 & 2 is conducted in conformance with RG 1.23 (Reference 2.3S-28), and will continue to be used during the operational phase for all four units.
Data collected by the meteorological monitoring system is used to:
Describe local and regional atmospheric transport and diffusion characteristics
Calculate the dispersion estimates for both postulated accidental and expected routine airborne releases of effluents
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Evaluate environmental risk from the radiological consequences of a spectrum of accidents
Provide an adequate meteorological database for evaluation of the effects from plant construction and operation, including radiological and non-radiological impacts and real-time predictions of atmospheric effluent transport and diffusion
2.3S.3.1 Site Description, Topographic Features of the Site Area and Location of Towers The STP site is located in a rural area of south-central Matagorda County. Matagorda County lies in the Coastal Prairie region in the southeastern part of Texas, along the Gulf of Mexico. The prominent natural features of the region include: the Colorado River, which bisects the county from north to south; East and West Matagorda Bays, which are protected by the Matagorda Peninsula; and Tres Palacios Bay and River. The west branch of the Colorado River, along with several sloughs, flows through the STP site boundary.
The major local effect on site meteorology is the presence of the Gulf of Mexico, which is approximately 15 miles south of the STP site at its closest point. The site vicinity and site area maps with an 8-kilometer (5-mile), 16-kilometer (10-mile) and 80-kilometer (50-mile) radius are shown on Figures 2.3S-15, 2.3S-17, and 2.3S-14, respectively. As shown on Figure 2.3S-14, terrain within 80 kilometers (50 miles) of the STP site is generally flat with variations less than 31 meters (100 feet) to the north and west. A 30-mile long broad band of open prairie extends inland along the Gulf of Mexico, with elevations averaging approximately 7 meters (23 feet) above MSL.
A 60-meter guyed meteorological tower serves as the primary data collection system and a 10-meter freestanding tower serves as a backup to the primary system. The backup meteorological system is a completely independent system installed and maintained for the purpose of providing redundant site-specific meteorological information (10-meter wind speed, wind direction, temperature, and sigma theta), representative of the site environment. The locations of the meteorological towers with respect to the existing and proposed units are shown on Figure 2.3S-18. The primary tower is located approximately 2.1 kilometers (1.3 miles) east of STP 3 & 4, while the backup tower is approximately 670.5 meters (2200 feet) south of the primary tower. Both locations are clear of man-made and natural obstructions which could influence the collection of meteorological data.
Factors considered in determining the location and installation of the instruments include prevailing wind direction, topography, and location of man-made and vegetative obstructions.
2.3S.3.2 Preoperational Monitoring Program RG 1.23 (Reference 2.3S-28) specifies the minimum amount of onsite meteorological data to be provided at the time of application for a combined license that does not reference an early site permit as a consecutive 24-month period of data that is defendable, representative, and complete, but not older than 10 years from the date of the application. It further states that three or more years of data are preferable.
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The 1999 and 2000 consecutive 24-month period of data taken for STP 1 & 2 was determined to be the most defendable (using validated data with least data substitution), representative (tower and sensor siting in accordance with RG 1.23 (Reference 2.3S-28), and complete (with annualized data recovery rate well in excessive of 90%), without being older than 10 years. Since RG 1.23 specifies that three or more years of data is preferable, three years (i.e., 1997, 1999, and 2000) of STP 1 & 2 data is used in support of the preoperational monitoring program for STP 3 & 4.
The findings presented below indicate that these three years of data are suitable for use in characterizing the atmospheric dispersion conditions for STP 3 & 4.
2.3S.3.2.1 Measurements Made, Elevation and Exposure of Instruments The meteorological monitoring system block diagrams reflecting the monitoring system configuration during 1997, 1999, and 2000 are provided as Figures 2.3S-19 and 2.3S- 20 for the primary and backup towers, respectively.
2.3S.3.2.1.1 Measurements Made The following measurements made during 1997, 1999, and 2000 constitute the preoperational monitoring program for STP 3 & 4:
Primary Tower – Wind speed, wind direction and ambient temperature at two levels, with dew point temperature, solar radiation and precipitation at one level
Backup Tower – Wind speed, wind direction and ambient temperature at a single level
2.3S.3.2.1.2 Instrument Elevations The meteorological instrumentation is located at multiple levels on the 60-meter guyed primary tower, and at a single level on the 10-meter backup tower. The meteorological instrumentation on these towers is summarized in Table 2.3S-12.
On the primary tower, wind speed and wind direction are measured at 10 meters (33 feet) and 60 meters (197 feet) above ground level. The reactor building plant stack has a height of 76 meters (249 feet) above ground. The accident atmospheric release points for the ABWR include the plant stack and several other elevations below the upper wind measurement height (i.e., 60 meters). Meteorological parameters measured for these releases are consistent with the guidelines in RG 1.23 (Reference 2.3S-28).
Ambient temperature is monitored both at the 10- and the 60-meter levels. Vertical differential temperature (i.e., ΔT) is calculated as the difference between the temperatures measured at 10 meters and at 60 meters. Dew point temperature is measured at the 3-meter level. Additional relative humidity/temperature instrumentation at 10 and 60 meters were added in 2006 for calculation of dew point temperature. These measurement heights represent water vapor release from a range of mechanical draft cooling towers to be considered for STP 3 & 4. Precipitation is
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measured at ground level near the base of the primary tower, while the solar radiation is measured at 2.5 meters above ground.
Wind speed, wind direction, wind direction standard deviation (i.e., sigma theta for atmospheric stability class determination), and ambient temperature are obtained at the 10-meter level on the backup tower.
2.3S.3.2.1.3 Exposure of Instruments The bases of both towers are at an elevation of approximately 8.5 meters (28 feet) MSL, while the finished plant grade of STP 3 & 4 is at 10.4 meters (34 feet) MSL along the road between STP 3 & 4, sloping to 9.8 meters (32 feet) MSL at the 4 corners of the power block. Because the base of the towers is at approximately the same elevation as the finished plant grade, and because there are minimal terrain variations within 8 kilometers (5 miles) of the site, as discussed in Subsection 2.3S.3.1, it is concluded that the locations of the meteorological tower sites and the proposed STP 3 & 4 have similar meteorological exposures. The tower and instrument siting conformance status in relation to RG 1.23 (Reference 2.3S-28) are summarized in Tables 2.3S-13 and 2.3S-14, respectively.
Obstructions RG 1.23 states that the wind sensors should be located over level, open terrain at a distance of at least 10 times the height of any nearby natural or man-made obstructions (e.g., terrain, trees and buildings), if the height of the obstruction exceeds one-half the height of the wind measurements (Reference 2.3S-28). An assessment of instrument obstructions was made and is described below:
The sizes of the environmental shelters housing the processing and recording equipment are: 3.4 meters x 3.4 meters x 3.3 meters (11 feet x 11 feet x 10.8 feet) for the primary system, and 2.4 meters x 3.0 meters x 2.7 meters (8 feet x 10 feet x 8.9 feet) for the backup system. These shelters are less than five meters in height, which is less than half of the lower level wind measurement height (10 meters), and are located downwind of the meteorological towers under the prevailing wind direction (i.e. south-southeast) to minimize wind turbulence and/or thermal effects on the meteorological measurements.
The surrounding terrain, nearby trees, and plant structures (existing and planned) were evaluated below to determine whether they could affect the meteorological measurements:
– As shown on Figure 2.3S-15, surrounding terrain of the meteorological towers is generally flat and no terrain-induced-airflow influence on the meteorological measurements is expected.
– Both the primary and backup meteorological towers are located in open fields. The nearby trees and brush range from 15 feet to 30 feet tall and mostly at 300 feet or more from the towers. These trees are trimmed periodically to ensure that the 10 times obstruction-height requirement is met (Reference 2.3S-28).
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– The tallest existing and planned buildings, which are located greater than 1.6 kilometers (1 mile) from the meteorological towers, for all four units are less than 76 meters (250 feet) in height. Separations between the meteorological towers and these buildings are much greater than 10 times their heights.
Wind sensors are mounted on a boom extending eight feet outward on the upwind side of the tower to minimize tower structure influence.
Therefore, it is concluded that the meteorological measurements are free of influence from any nearby natural or man-made obstructions.
Heat and Moisture Sensors Based on the structure layout as shown in Figures 2.3S-19 through 2.3S-22, the ambient temperature and dew point instrumentation on the existing towers were assessed to determine whether they would be affected by any heat or moisture sources (e.g., ventilation sources, cooling towers, water bodies, large parking lots, etc.) and the findings are presented below:
Both the primary and backup towers are located on open fields with grassy surfaces underlying the tower. As shown in Figure 2.3S-18, there are no large concrete or asphalt parking lots or temporary land disturbances such as plowed fields or storage areas nearby. The closest large concrete or asphalt parking lots and ventilation sources are located at STP 1 & 2, which is more than one mile from the meteorological towers.
The proposed plant cooling system for STP 3 & 4 includes the existing Main Cooling Reservoir (MCR) and two banks of mechanical draft cooling towers. As shown on Figure 2.3S-18, the MCR is approximately one mile southwest of the primary meteorological tower at its closest point, while the cooling towers are located directly west, at a distance greater than 1.3 miles from the meteorological towers. The STP 1 & 2 essential cooling pond is approximately 3500 feet and 2600 feet from the primary and backup towers, respectively.
With the large separation distance between the meteorological towers and the cooling towers and Essential Cooling Pond, their influence on the ambient temperature, dew point and relative humidity instrumentation is expected to be minimal. However, due to the relatively large size of the MCR (>7000 acres), it is expected that the MCR would have an influence on the observed meteorological data when the meteorological tower is downwind (south to southwest winds) from the MCR. For example, the dew point measurement is expected to be somewhat higher when the tower is downwind of the MCR and warmer temperatures from the MCR would tend to increase the lower level temperature and increase thermal instability. This effect would enhance the dispersion of releases occurring near the plant site under the south to southwest winds.
In addition, temperature sensors are mounted in fan-aspirated radiation shields, which are pointing downward to minimize the impact of thermal radiation and precipitation.
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Wind Loss The precipitation gauge is equipped with wind shields to minimize the loss of precipitation caused by wind.
2.3S.3.2.2 Description of Instruments Used Sensor type, manufacturer, and model for the STP 1 & 2 meteorological data collection system during the preoperational monitoring period of 1997, 1999 and 2000 are provided in Table 2.3S-15. Block diagrams of the primary and backup systems are presented in Figures 2.3S-19 and 2.3S-20.
2.3S.3.2.2.1 Instrument Performance Specification Sensor specifications (including sensor starting threshold, range, and measurement resolution), and system accuracy for the data collection system during the preoperational monitoring period are provided in Table 2.3S-15.
2.3S.3.2.2.2 Sensor Operating Experience Meteorological sensors used on both the primary and backup meteorological towers are designed to operate in the environmental conditions found at the STP site. Specifically, this instrumentation is capable of withstanding the following environmental conditions
Ambient temperature range of –4°F to +248°F
Wind load up to 125 mph (55.88 m/s) @ 30 feet on a 100-year recurring interval
Relative humidity range of 0% to 100%
In July of 2003, the eye of a small hurricane (Claudette) passed south of the site and both towers and their equipment at the 10-meter level survived winds in excess of 80 mph.
The instruments on the towers are off-the-shelf components and are used universally throughout the nuclear industry and others for the purpose of meteorological measurement. Based on operating experience, the only adverse operational effects that have been noted was the susceptibility of the rotating-cup and weather vane instruments to bearing wear and degradation due to the site environmental conditions that required the instruments to be replaced approximately every 6 months. This type of wind sensor was replaced in 2005 with an ultrasonic sensor that has no moving parts.
2.3S.3.2.3 Calibration and Maintenance Procedures Calibration and maintenance of the onsite meteorological monitoring system are performed in accordance with RG 1.23, Regulatory Position C.5, Instrument Maintenance and Servicing Schedules (Reference 2.3S-28) and ANSI/ANS 3.11, Section 7, System Performance (Reference 2.3S-37).
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The existing meteorological monitoring system is calibrated semi-annually at both the primary and backup towers, and channel checks are performed daily in order to achieve maximum data recovery. System operability is also checked by using the system dial-up capability to remotely monitor the system status.
Detailed instrument calibration procedures and acceptance criteria are strictly followed during system calibration. Calibrations verify and, if necessary, reestablish accuracies of sensors, associated signal processing equipment and displays. Routine calibrations include obtaining both “as-found” (prior to maintenance) and “as-left” (final configuration for operation) results. The end-to-end results are compared with expected values. Any observed anomalies which may affect equipment performance or reliability are reported for corrective action. If any acceptance criteria is not met during the performance of calibration procedures, timely corrective measures (e.g., adjusting response to conform with desired results by onsite qualified personnel or returning the sensor to the vendor for calibration) are initiated.
Inspection, service and maintenance, including preventive and/or corrective maintenance on system components for transmitting, manipulating, and/or processing meteorological data for computer display and storage, are performed according to the instrument manuals and plant surveillance program procedures to maintain at least 90% data recovery.
Maintenance and calibration activities on the primary tower are facilitated by the addition of an instrument elevator. The monitoring system is equipped with lightning protection and a redundant power supply.
2.3S.3.2.4 Data Output and Recording System and Location Independent microprocessors are used as the primary data collection system for the primary and backup meteorological towers, with digital data recorders used as a backup data collection system.
The microprocessors sample the meteorological processor modules once per second for each parameter measured except for precipitation. Water collected by the rain gauge is automatically drained and counted each time an internal bucket fills with 0.01 inch of rainfall.
The microprocessors provide current sampling values as well as the 15- and 60-minute averages. Sigma theta is computed for each wind direction channel via the microprocessor. These calculated averages are output to the digital data recorders and on diskette and/or CD for system monitoring, data verification, and processing uses. In addition, the current values and the calculated averages including the data quality status flags are sent electronically to the Emergency Response Facility Data Acquisition and Display System (ERFDADS).
As shown on Figures 2.3S-19 and 2.3S-20, data was collected and stored by a RM21A computer independent of the meteorological tower and the local plant computers. From the retirement of the RM21A computer at the beginning of 2002 to present, data has been averaged on the meteorological tower computers and transmitted to the local
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plant computers for storage and report generation. Refer to Figures 2.3S-21 and 2.3S- 22 for the system block diagrams for the current configuration.
Since December 2006, hourly average data from the new 10- and 60-meter dew point instruments has been recorded by a data logger attached to the base of the primary meteorological tower. Approximately once a week, the data is transmitted to a personal computer (PC) for review and electronic storage. A printed copy of the data is transmitted to the records management system for permanent storage approximately once per month.
The processing and recording equipment are housed in environmentally controlled (air conditioned) shelters. A direct readout capability from these recorders is included.
2.3S.3.2.5 Data Display, Processing, Archiving and Analysis Following an upgrade of the meteorological instrumentation in 1994 to meet emergency preparedness requirements, data has been collected and electronically transmitted to various plant computers for data validation, screening, display, storage and report generation.
2.3S.3.2.5.1 Data Display The ERFDADS provides 15-minute averages of meteorological data for real-time display in the Control Room, Technical Support Center, and Emergency Operations Facility in accordance with RG 1.97 (Reference 2.3S-36). The STP 1 & 2 control rooms also display current 15 minute and 60-minute averages for the 10-meter level wind speed and direction via analog meters.
The 15- and 60-minute averaged wind speed, wind direction, and atmospheric stability data are submitted as inputs to the NRC's ERDS and this data can be accessed by the NRC.
2.3S.3.2.5.2 Data Processing and Analysis Computer programs are used in the screening process to identify recurring types of data errors, including the following items:
Missing data (out-of-range values) and unchanging data for the 10-meter wind speed, wind direction, and ΔT for the primary tower.
The daily average difference between the primary and backup tower wind speeds and wind directions measured at 10 meters.
Periods of daytime stable and nighttime unstable conditions.
In addition, visual scanning of the 10-meter wind speed and direction data is routinely performed for abnormal values or inconsistency.
Hourly average data is downloaded and formatted monthly for review and editing. Acceptable data editing methods have been established and implemented. Missing or
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invalid primary tower 10-meter wind speed, wind direction, and ΔT data are manually replaced with backup tower data.
Dew point data screening consists of plotting the ground level (approximately 3 meters), 10 meter, and 60-meter dew point temperatures using a spreadsheet program. Periods of strong divergence suggest questionable data.
2.3S.3.2.5.3 Data and System Validation The microprocessors provide validation checks on the 15-minute averaged data. These checks consist of electrical status (i.e., system within predefined calibration test limits) and meteorological validations. System validations include the following checks: AC power, generator on-line, propane level, aspirators (to reduce temperature measurement errors), and hard-disk availability. Meteorological validations are performed to ensure accurate data transmission from the sensors and include checks such as minimum wind speed, minimum wind direction, wind speed, and wind direction comparisons between the 10- and 60-meter levels, temperature ranges, and hourly ΔT limits.
2.3S.3.2.5.4 Data Archiving An additional feature of the Data Acquisition System is the storage of the 15- and 60- minute averaged meteorological data. At a minimum, the latest 12 months of averaged data resides on the system hard-drive. The historical data can be retrieved, archived, displayed, or printed.
Hourly averaged data is stored on local plant computers for trending and reporting purposes in accordance with RG 1.21, (Reference 2.3S-39).
2.3S.3.2.6 System Accuracy Sources of error for time-averaging digital systems include: sensors, cables, signal conditioners, temperature environments for signal conditioning and recording, equipment, recorders, processors, data displays, and data reduction process.
The system accuracies of the proposed STP 3 & 4 meteorological data collection system were compared against the regulatory requirements and the findings are summarized in Table 2.3S- 15. As shown in the table, the system accuracies of the proposed system meet the regulatory guidance in accordance with RG 1.23 (Reference 2.3S-28) and ANSI/ANS 3.11 (Reference 2.3S-37). In addition, the associated recording equipment accuracies are reported in Table 2.3S-16 (Reference 2.3S-40).
2.3S.3.3 Operational Program The STP 1 & 2 onsite meteorological monitoring program is conducted in accordance with the guidance and system accuracy specified in RG 1.23 (Reference 2.3S-28). This program, including the calibration and maintenance procedures described in Subsection 2.3S.3.2.3, and the data display, processing, archiving, and analysis
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procedures described in Subsection 2.3S.3.2.5 will continue to be used as the operational onsite meteorological monitoring program for STP 1, 2, 3 & 4.
2.3S.3.3.1 Meteorological Instrumentation The meteorological monitoring system block diagrams for the current system are provided in Figures 2.3S-21 and 2.3S-22 for the primary and backup towers, respectively. Sensor specifications (including sensor starting threshold, range, and measurement resolution), and system accuracy for the current configuration are provided in Table 2.3S-17.
All meteorological parameter data signals from the existing tower come through an analog-to-digital converter processor at the meteorological tower shelter, and then to the data logger for conversion, storage and transmission. The data logger converts, tracks, trends and transmits the data to shared data files located on two local computers. These shared data files are transmitted via wireless antenna to the Integrated Computer System (ICS), where the data is transmitted to all ICS workstations in the plants as well as in the emergency facilities. The ICS stores the data for 18 months, after which it is transferred to a designated facility for permanent storage.
Separate, independent data links to the new units, including data recording system, display, processing, analysis, and archiving for STP 3 & 4 will be designed and installed in accordance with the applicable regulatory requirements. The architecture of these systems and programs will be similar to those of the current meteorological data collection system for STP 1 & 2.
2.3S.3.3.2 Emergency Preparedness Support The STP 3 & 4 onsite data collection system is used to provide representative meteorological data for use in real-time atmospheric dispersion modeling for dose assessments during and following any accidental atmospheric radiological releases. The data is also used to represent meteorological conditions within the 10-mile Emergency Planning Zone radius (References 2.3S-41, 2.3S-42, 2.3S-43, and 2.3S- 44).
Similar to the STP 1 & 2 onsite meteorological monitoring program, the microprocessors sample the meteorological processor modules once per second for each of the following parameters in order to provide near real-time meteorological data for use in atmospheric dispersion modeling: wind speed, wind direction, and ambient temperature for calculations of vertical temperature difference. Dose assessment calculations are performed using the most recent 15-minute averaged data in accordance with RG 1.97 (Reference 2.3S-44).
In order to identify rapidly changing meteorological conditions for use in performing emergency response dose consequence assessments, 15-minute average values are compiled for real-time display in the STP 3 & 4 Control Room, Technical Support Center, and Emergency Operations Facility. All of the meteorological channels
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required for input to the dose consequence assessment models are available and presented in a format compatible for input to these dose assessment models.
Provisions are currently in place to obtain representative regional meteorological data from the NWS or Impact Weather Service (current meteorological contractor for STP 1 & 2) during an emergency if the site meteorological system becomes unavailable. The current (or similar) emergency plan procedures and the monitoring system arrangement will continue to be used for STP 3 & 4.
2.3S.3.4 Meteorological Data Three years (1997, 1999, and 2000) of STP onsite meteorological data is provided with the application. This data was used to calculate (1) the short-term atmospheric dispersion estimates for accident releases discussed in Subsection 2.3S.4 and (2) the long-term atmospheric dispersion estimates for routing releases discussed in Subsection 2.3S.5.
2.3S.3.4.1 Representativeness and Adequacy of Data The three years of data used in the atmospheric dispersion estimates was determined to be (1) the most defendable, because the data has been validated and require the least data substitution as discussed in Subsections 2.3S.3.2.3 and 2.3S.3.2.5, (2) representative, because the meteorological tower and sensor siting were performed in accordance with RG 1.23 (Reference 2.3S-28), as discussed in Subsection 2.3S.3.2.1, and (3) complete with annualized data recovery rate well in excessive of 90% as shown in Table 2.3S-18.
2.3S.3.4.1.1 Climatic Representativeness Long-term meteorological data from Victoria, Corpus Christi, and Galveston NWS stations, along with onsite data from the STP site, has been examined extensively in the STP 1 & 2 UFSAR (Reference 2.3S-40). Comparisons show relatively close agreement between the offsite NWS data and the onsite data for average wind direction and speed, frequency of calm, wind direction persistence, prevailing wind direction, and atmospheric stability. Therefore, the onsite meteorological data is considered to be reasonably representative of the long-term climatological average.
2.3S.3.4.1.2 Long-Term Conditions The annual wind rose for the 3-year data period 1997, 1999 and 2000 (Subsection 2.3S.2, Figure 2.3S-2), was compared against the wind rose from onsite data collected for the periods July 21, 1973 through July 20, 1976 and October 1, 1976 through September 30, 1977 (Reference 2.3S-40, Figure 2.3S-3) to show how well this data represents long-term conditions at the STP site.
Although the data periods are more than thirty years apart, the comparison shows that there is close correlation in wind distribution with predominant winds from the south- southeast as shown in Table 2.3S-19. The annual frequency of calms, as presented in the STP 1 & 2 UFSAR (Reference 2.3S-40, Table 2.3S-9), was 0.32%, which is just slightly higher than the percent of calm winds specified in the STP 3 & 4 FSAR 2.3S.2,
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Figure 2.3S-2 (0.00%). The annual average wind speed (Reference 2.3S-39, Table 2.3S-9) is also slightly higher than the annual average wind speed presented in Table 2.3S-6 (10.7 mph vs. 9.2 mph, respectively). Therefore, these figures show relatively close agreement to each other.
The distribution of stability class for these two data sets is presented in Table 2.3S-20. As shown in the table, the two data sets show close agreement to each other.
The STP 1 & 2 UFSAR (Reference 2.3S-40) provides an evaluation showing that the onsite meteorological data is representative of the long-term climatological average; therefore, it is appropriate to conclude that the recent onsite data (i.e., 1997, 1999 and 2000) used in support of STP 3 & 4, is also reasonably representative of the long-term climatological average.
2.3S.3.4.1.3 Need for Additional Data Sources for Airflow Trajectories Topographic features and the dispersion characteristics of the site area were examined in Subsections 2.3.2 and 2.3.3.1. The site area is generally flat and is concluded to be an open terrain site. The airflow in the site area is dominated mostly by large-scale weather patterns and infrequent recirculation of airflow during periods of prolonged atmospheric stagnation.
The NRC-sponsored computational model (XOQDOQ), based on RG 1.111 (Reference 2.3S-45), is a constant mean wind direction model, using meteorological data from a single station to calculate dispersion estimates out to 50 miles from a site of interest. Terrain induced airflow-recirculation factor options are provided in the model to account for the effects of airflow recirculation phenomenon occurring within the area of interest, when meteorological data from a single station is used to represent the entire modeling domain. However, application of airflow-recirculation factors for sites located within open terrain is not required. This methodology implies that the meteorological data from an onsite station is reasonably representative of the entire modeling domain and adjustment to the dispersion estimates calculated by the model out to 50 miles of a site located within open terrain is not required.
For coastal sites located within open terrain such as the STP site, an airflow- recirculation factor provided in the XOQDOQ model is used to account for potential airflow recirculation due to sea breeze and land breeze effects, and during the infrequent stagnation conditions that could lead to more restrictive dispersion estimates. With application of the appropriate airflow recirculation factor, this methodology further implies that using data collected from an onsite meteorological monitoring station located within open terrain for making dispersion estimates out to 50 miles of a coastal site is considered to be adequate and acceptable.
Therefore, data collected by the STP 1 & 2 collection system can be used for the description of atmospheric transport and diffusion characteristics within 80 kilometers (50 miles) of STP 3 & 4 and for making dispersion estimates out to 50 miles from the site. No other offsite data collection systems are necessary to determine the dispersion characteristics of the STP site area.
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2.3S.3.4.1.4 Supplemental Data for Environmental Impact Evaluations Meteorological data collected at the Palacios Municipal Airport was used to supplement the onsite STP data for environmental impact evaluations resulting from operation of STP 3 & 4. The weather station at Palacios Municipal Airport is an Automated Service Observation System (ASOS) Coop Station, at which continuous, hourly meteorological measurements (e.g., wind speed, wind direction, temperature, dew point, relative humidity, precipitation, visibility, cloud cover and altimeter) have been made since April 1, 1940. This ASOS Station is the closest national weather station, which is located on the west bank of the Palacios Bay and approximately 13.5 miles southwest of the STP site. The major local effect on the area meteorology is the presence of the Gulf of Mexico. Due to the relatively short distance between the Palacios ASOS station and the STP site and the similarity in meteorological exposure between these two locations, data collected at the Palacios ASOS station is considered to be representative of the STP site.
Data collected at the Palacios ASOS station (i.e., dew point, relative humidity, visibility, cloud cover and altimeter) from 1997 through 2001, in conjunction with the concurrent wind speed, wind direction and stability class determined from the existing STP meteorological monitoring program, was used to evaluated cooling tower plume impacts resulting from operation of STP 3 & 4.
For evaluation of the environmental risk from the radiological consequences of a spectrum of severe accidents, the same period of hourly precipitation data collected at the Palacios ASOS Station in conjunction with the concurrent wind speed, wind direction and stability class determined from the existing meteorological data collection system for STP 1 & 2 was used.
2.3S.3.4.2 Data Recovery Rate and Annual Joint Frequency Distribution of Data Three years of representative data (i.e., 1997, 1999, and 2000) collected at the existing primary and backup towers are used in preparing the STP 3 & 4 COLA. The data set satisfies the guidance provided in RG 1.23 (Reference 2.3S-28).
The annualized data recovery rates for 1997, 1999, and 2000 are presented in Table 2.3S-18 for the individual parameters (i.e., wind speed and wind direction by stability class) and the composite parameters. As shown in the table, all data recovery rates exceed 90% as specified in RG 1.23 (Reference 2.3S-28).
The required joint frequency distributions are presented in Subsection 2.3S.2, Tables 2.3S-10 and 2.3S-11 in the format described in RG 1.23 for the following: wind speed and wind direction by stability class and by all stability classes combined for the 10- and 60-meter levels measurements.
2.3S.3.4.3 Supplemental Submittal to the Application An electronic sequential, hour-by-hour listing of the data set, including stability class covering the three-year period (i.e., 1997, 1999, and 2000) in the format described in RG 1.23, has been generated and is provided with the application.
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2.3S.4 Short-Term Atmospheric Diffusion Estimates for Accident Releases The following site-specific supplement addresses COL License Information Item 2.11.
2.3S.4.1 Objective To evaluate potential health effects of design-basis accidents at STP 3 & 4, a hypothetical accident is postulated to predict upper-limit concentrations and doses that might occur in the event of a containment release to the atmosphere. Site-specific meteorological data covering the 3-year period of record for 1997, 1999 and 2000 was used to quantitatively evaluate such a hypothetical accident at the site. Onsite data provide representative measurements of local dispersion conditions appropriate to the STP site and a 3-year period is considered to be reasonably representative of long- term conditions as discussed in Subsection 2.3S.3.2.3.
According to 10 CFR Part 100, (Reference 2.3S-46) it is necessary to consider the doses for various time periods immediately following the onset of a postulated radioactive airborne release at the exclusion area boundary (EAB) and for the duration of the exposure for the low population zone (LPZ) and the population center distances. The relative atmospheric dispersion factors (χ/Qs) are estimated for various time periods ranging from 2 hours to 30 days.
Meteorological data has been used to determine various postulated accident conditions as specified in RG 1.145 (Reference 2.3S-47). Compared to an elevated release, a ground-level release usually results in higher ground-level concentrations at downwind receptors due to less dispersion as a result of shorter traveling distances. Since the ground-level release scenario provides a bounding case, elevated releases are not considered. Approaches used in estimating χ/Qs follow guidance suggested in RG 1.145 (Reference 2.3S-47).
Portions of the EAB and the outer boundary of the LPZ extend over the MCR. Smaller surface roughness induced by the MCR would result in less turbulence, and consequently generates slightly higher χ/Qs at portions of the EAB and the LPZ that extend over the MCR. However, reduced surface roughness would also increase ambient wind speed slightly and reduce the χ/Qs due to better dispersion. The above effects counter each other and subsequently minimize the net effect of reduced surface roughness on the offsite short-term atmospheric dispersion estimates.
2.3S.4.2 Calculations The PAVAN computer code, as described in NUREG/CR-2858 (Reference 2.3S-48), is used to estimate ground-level χ/Qs at the EAB and LPZ for potential accidental releases of gaseous radioactive material to the atmosphere. This assessment is required by 10 CFR Part 100 (Reference 2.3S-46).
As shown on Figure 2.1S-3 and as described in Subsection 2.1S.2, the EAB for STP 3 & 4 is an oval, centered at a point (305 ft) directly west of the center of the Unit 2 Reactor Building. Since the EAB is centered on the existing STP 1 & 2, the distances to the EAB from the envelope surrounding the STP 3 & 4 power block are different for each directional sector. These distances are specified in Table 2.3S-21.
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The LPZ is a 3-mile radius circle centered at the same point as the EAB (Subsection 2.1S.2). The distances from the envelope surrounding the STP 3 & 4 power block to the LPZ are specified in Table 2.3S-21.
The PAVAN program implements the guidance provided in RG 1.145 (Reference 2.3S- 47). The code computes χ/Qs at the EAB and LPZ for each combination of wind speed and atmospheric stability class for each of 16 downwind direction sectors (i.e., north, north-northeast, northeast, etc.). The χ/Q values calculated for each direction sector are then ranked in descending order, and an associated cumulative frequency distribution is derived based on the frequency distribution of wind speeds and stabilities for the complementary upwind direction sector. The χ/Q value that is equaled or exceeded 0.5% of the total time becomes the maximum sector-dependent χ/Q value.
The calculated χ/Q values are also ranked independent of wind direction to develop a cumulative frequency distribution for the entire site. The PAVAN program then selects the χ/Qs that are equaled or exceeded 5% of the total time.
The larger of the two values (i.e., the maximum sector-dependent 0.5% χ/Q or the overall site 5% χ/Q value) is used to represent the χ/Q value for a 0-2 hour time period. To determine χ/Qs for longer time periods, the program calculates an annual average χ/Q value using the procedure described in RG 1.111 (Reference 2.3S-45). The program then uses logarithmic interpolation between the 0-2 hours χ/Qs for each sector and the corresponding annual average χ/Qs to calculate the values for intermediate time periods (i.e., 0-8 hours, 8-24 hours, 1-4 days, and 4-30 days).
The PAVAN model has been configured to calculate offsite χ/Q values assuming both wake-credit allowed and wake-credit not allowed. For all sectors, the EAB and LPZ are located beyond the wake influence zone induced by the Reactor Building. Therefore, the “wake-credit not allowed” scenario of the PAVAN results has been used for the χ/Q analyses at both the EAB and the LPZ.
The PAVAN model input data is presented below:
Meteorological data: 3-year (1997, 1999 and 2000) composite onsite joint frequency distributions (JFDs) of wind speed, wind direction, and atmospheric stability (see Subsection 2.3S.3).
Type of release: Ground-level
Wind sensor height: 10 meters
Vertical temperature difference: as measured at the 10-meter and 60-meter levels of the primary meteorological tower
Number of wind speed categories: 11
Release height: 10 meters (default height)
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Distances from release point to EAB for all downwind sectors
Distances from release point to LPZ for all downwind sectors
The PAVAN model uses building cross-sectional area and containment height to estimate wake-related χ/Q values. If the EAB and the LPZ are both located beyond the building wake influence zone, these two input parameters have no effect in calculating the non-wake χ/Q values.
To be conservative, the shortest distance in each sector from the STP 3 & 4 power block envelope to the EAB was entered as input for each downwind sector to calculate the χ/Q values at the EAB. Similarly, the shortest distance from the STP 3 & 4 power block envelope to the LPZ is entered as input to calculate the χ/Q values at the LPZ.
2.3S.4.2.1 Postulated Accidental Radioactive Releases
2.3S.4.2.1.1 Offsite Dispersion Estimates Based on the PAVAN modeling results, the maximum 0 to 2-hour, 0.5 percentile, direction-dependent χ/Q value is compared with the 5 percentile overall site 0 to 2-hour χ/Q value at the EAB. The higher of the two is used as the proper χ/Q at the EAB for each time period. The same approach is used to determine the proper χ/Qs at the LPZ.
The PAVAN-generated 0.5% value maximum χ/Qs presented in Tables 2.3S-23 and 2.3S-24 for the EAB and the LPZ, respectively, are summarized below for the 0 to 2- hour time period, the annual average time period, and other intermediate time intervals evaluated by the PAVAN model.
Receptor 0 – 2 0 – 8 8 – 24 1 – 4 4 – 30 Annual Location hours hours hours days days Average EAB 2.74E-04 1.85E-04 1.52E-04 1.02E-04 5.96E-05 3.09E-05 LPZ 5.27E-05 2.45E-05 1.67E-05 7.57E-06 2.59E-06 7.09E-07 The results provided in Tables 2.3S-23 and 2.3S-24 show that the χ /Q values determined by the PAVAN modeling analyses at the EAB and LPZ, respectively, are bounded by the ABWR standard plant site design parameters as defined in Table 2.0- 1 of the reference ABWR DCD. The PAVAN-predicted maximum 0-2 hours EAB 0.5% χ/Q (2.74E-04), as well as the maximum 2-hour EAB 5% χ/Q value (1.62E-04), is lower than the corresponding reference ABWR DCD EAB χ/Q value (1.37E-03). Similarly, the PAVAN-predicted maximum 0-2 hours LPZ 0.5% χ/Q value (5.27E-05), as well as the maximum 2-hour 5% χ/Q value (3.99E-05), is lower than the corresponding reference ABWR DCD LPZ χ/Q value (4.11E-04).
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2.3S.4.2.1.2 Onsite Dispersion Estimates In addition, χ/Qs are estimated at the control room and the Technical Support Center (TSC) for postulated accidental radioactive airborne releases.
Control room χ/Qs are estimated using the ARCON96 model as described in NUREG/CR-6331 (Reference 2.3S-50) and considers the control room air intake height, release height, release type, and building area. Hourly meteorological data collected onsite during 1997, 1999, and 2000 is used as part of the input for the ARCON96 program. The three years of meteorological data identified above in Subsection 2.3S.4.1 all have data recovery rates of greater than 90%, and are representative of the site dispersion characteristics as described in Subsection 2.3S.3.
As discussed in Subsection 15.6.5.5.3 of the reference ABWR DCD, the control room may be contaminated from two sources: the Reactor Building stack base or the Turbine Building truck doors. Subsection 11.3.10 of the reference ABWR DCD also provides information on radioactive releases. The locations of the sources and receptors are provided in Figure 2.3S-23. RG 1.194 (Reference 2.3S-51) provides guidance on the use of ARCON96 for determining χ/Qs to be used in design basis evaluation of control room radiological habitability. The Reactor Building stack base, at 26.2 meters and the Turbine Building truck doors, located at the ground level, were treated as ground-level sources. For STP 3 & 4, each unit has two control room air intakes and a TSC air intake (as shown in Figure 2.3S-23). These three intakes were treated as receptors in ARCON96 modeling.
The reactor building plant stack is located close to the middle of the west side of the Reactor Building; the turbine building truck doors are located to the north-west corner of the Turbine Building. The control room air intakes are located to the north-west (designated as B in Table 2.3S-25) and north-east (designated as C in Table 2.3S-25) corners of the Control Building; the TSC air intake is conservatively assumed to be located at the southwest comer ofthe Service Building for Reactor Builqing releases and at the northwest corner of the Service Building for Turbine Building releases. Guidelines provided in RG 1.194 (Reference 2.3S-51) were followed in estimating the χ/Q values at the control room and TSC air intakes.
The 95 percentile control room and TSC χ/Qs for time averaging (0 to 2 hours, 2 to 8 hours, 8 to 24 hours, 1 to 4 days and 4 to 30 days) obtained from the ARCON96 modeling results are summarized in Table 2.3S-25.
The results provided in Table 2.3S-25 show that the χ/Q values determined by the ARCON96 modeling analyses at the control room and TSC air intakes for Reactor Building stack releases are bounded by the corresponding χ/Q values in Tables 15.6- 3, 15.6-7, 15.6-13, 15.6-14, and 15.6-18 of the reference ABWR DCD, except in two instances.
The ARCON96 modeling results show that the maximum 4-30 day χ/Q value at one of the control room air intakes due to Reactor Building stack base releases is 5.59 E-04, which is slightly greater than the maximum 4-30 day χ/Q value of 5.12E-04 from DCD table 15.6-14. Also, the maximum 4-30 day χ/Q value at the same intake for turbine
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building truck door releases is 9.15E05. As discussed in a foot note for DCD Table 15.6-14, the control room χ/Q values for releases from turbine building are a factor of six less than reactor building χ/Q values. Therefore, the 4-30 day average control room χ/Q value (5.12E-04) due to reactor building releases (see DCD Table 15.6-14) is equivalent to a control room χ /Q value of 8.53E-05 for turbine building releases. The ARCON96-calculated 4-30 day control room χ/Q values due to reactor building plant stack (5.59E-04) and turbine building truck door (9.15E-05) releases slightly exceeds the corresponding DCD χ/Q values of 5.12E-04 and (8.53E-05), respectively. The maximum 4-30 days χ/Q values exceed the corresponding reference ABWR DCD χ/Q values by 9% and 7%, respectively. The exceedance of a χ/Q value does not result in the violation of the NRC dose limit. The ultimate factor that would affect the plant design is the radiation dose as discussed in FSAR Section 15.6.
2.3S.4.2.2 Hazardous Material Releases Pollutant concentrations are also estimated at the STP 3 & 4 control room and the TSC air intakes for postulated accidental releases of hazardous materials (i.e., flammable vapor clouds, toxic chemicals, and smoke from fires) from materials stored onsite, offsite and for toxic or flammable material transported on nearby transport routes. The concentrations at the control room and TSC intakes due to accidental hazardous chemical releases (toxic vapor and flammable cloud) were determined using the guidance specified in RG 1.78 (Reference 2.3S-52).
Detailed description of potential accidents to be considered as design-basis events and their impacts are discussed in Subsection 2.2S.3.1. The effects of the potential explosion events from both internal and external sources are summarized in Tables 2.2S-9 and 2.2S-10. Estimated values of control room concentrations due to potential hazardous material releases are presented in Table 2.2S-11. The analyses indicate that none of the potential events would adversely affect the safe operation or shutdown of STP 3 & 4.
2.3S.5 Long-Term Atmospheric Dispersion Estimates for Routine Releases The following site-specific supplement addresses COL License Information Item 2.12.
2.3S.5.1 Objective This section provides estimates of annual average atmospheric dispersion factors (χ/Q values) and relative dry deposition factors (D/Q values) to a distance of 50 miles (80 kilometers) from the STP site for annual average release limit calculations and person- rem estimates.
The NRC-sponsored XOQDOQ computer program (Reference 2.3S-53) was used to estimate χ/Q and D/Q values from routine releases of gaseous effluents to the atmosphere. The XOQDOQ computer code has the primary function of calculating annual average χ/Q and D/Q values at receptors of interest (e.g., site boundaries, nearest milk animal, nearest resident, nearest vegetable garden, and nearest meat animal). RG 1.206 (Reference 2.3S-36) calls for χ/Q and D/Q estimates at the above receptor of interest. 10 CFR Part 100 (Reference 2.3S-46) requires an "exclusion area" surrounding the reactor in which the reactor licensee has the authority to
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determine all activities, including exclusion or removal of personnel and property. Since the Exclusion Area Boundary (EAB) encompasses the shortest site boundary, the direction-dependent exclusion area boundaries were conservatively used in χ/Q and D/Q estimates.
The XOQDOQ dispersion model implements the assumptions outlined in RG 1.111 (Reference 2.3S-45). The program assumes that the material released to the atmosphere follows a Gaussian distribution around the plume centerline. In estimating concentrations for longer time periods, the Gaussian distribution is assumed to be evenly distributed within a given directional sector. A straight-line trajectory is assumed between the release point and all receptors.
Since the NRC-sponsored XOQDOQ model was used in the analysis, diffusion σ σ parameters ( y and z) as specified in RG 1.145 (Reference 2.3S-47) and implemented by the XOQDOQ code were used in estimating the χ/Q and D/Q values. The following input data and assumptions have been used in the XOQDOQ modeling analysis:
Meteorological data: 3-year (1997, 1999, and 2000) composite onsite joint frequency distributions of wind speed, wind direction, and atmospheric stability (see Subsection 2.3S.3). The determinations for the atmospheric stability classes were based on the vertical ΔT method as specified in RG 1.145 (Reference 2.3S- 47).
Type of release: Ground-level
Wind sensor height: 10 meters
Vertical temperature difference: (10 meters - 60 meters)
Number of wind speed categories: 11
Release height: 10 meters (default height)
2 Minimum building cross-sectional area: 2134 m (reactor building structure, including building tapers and all appurtenances)
Reactor building height: 37.7 meters above grade
Distances from the release point to the nearest residence, nearest EAB boundaries, vegetable garden, milk animal, and meat animal.
No residential milk cows have been identified within 5 miles of the STP site, and no dairies have been identified within 50 miles. It is conservatively assumed that all residents have a vegetable garden and are fattening a calf for residential consumption.
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χ/Q and D/Q values at the Unit 4 reactor were estimated based on the assumption that the Unit 3 reactor is operational while the Unit 4 reactor is still under construction.
The ABWR reactor design has been used to calculate the minimum building cross- sectional area as called for in NUREG/CR-2919 (Reference 2.3S-53) for evaluating building downwash effects on dispersion.
Distances from the STP 1 & 2 reactors to various receptors of interest (i.e., nearest residence, meat animal, site boundary, and vegetable garden) for each directional sector are provided in the STP 1 & 2 Offsite Dose Calculation Manual (Reference 2.3S-54). The shortest distances from the STP 3 & 4 Reactor Building plant stacks to these same receptors of interest are recalculated for each directional sector. The results are presented in Table 2.3S-26. Tables 2.3S-26a and 2.3S-26b provide downwind distances to the EAB and site boundary in each sector that were used to derive the set of maximum annual EAB and site boundary χ/Q and D/Q values.
Smaller surface roughness leads to minimal changes in χ/Q values. Lower surface roughness over the MCR would increase wind speeds resulting in lower χ/Q values. This is balanced by decreasing production of mechanical turbulence, leading to decreased dispersion and higher χ/Q. The decrease in turbulence is also offset by the increased destabilization over the MCR due to the heating from below of the overwater trajectories. Warm water in the MCR heating ambient air from below will destabilize the atmosphere passing over the MCR. Increased instability will, in turn, enhance local dispersion, lowering overall routine release χ/Q values. In addition, Sea Breezes from the Gulf of Mexico will tend to increase routine release χ/Q values due to local air recirculation. The cool air moving from the Gulf of Mexico will tend to stabilize the atmosphere, in addition to the recirculation of polluted air.
Because cooling water temperatures will slightly increase local ambient air temperatures, the presence of the MCR will increase local air instability. Increased instability will, in turn, enhance local dispersive properties, lowering overall routine release χ/Q values. In addition, sea breezes from the Gulf of Mexico will tend to increase routine release χ/Q values due to local air recirculation.
To account for possible effects from Matagorda Bay and the Gulf of Mexico on local meteorological conditions, default correction factors were implemented in the XOQDOQ (and PAVAN) model(s). These factors were implemented to satisfy section C2.c of RG 1.111 (Reference 2.3S-45) and properly account for possible recirculation due to land-water boundaries, which could raise χ/Q values in an open terrain area such as the STP plant site.
As discussed in Subsection 2.3S.3, the onsite meteorological data provides representative measurements of local dispersion conditions appropriate to the STP 3 & 4 site, and a 3-year period is considered to be reasonably representative of long-term conditions for routine releases. Therefore, the lower level (10 meter) 3-year (1997, 1999 and 2000) joint frequency distributions of wind speed, wind direction, and atmospheric stability were used as input in the XQODOQ modeling analysis.
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2.3S.5.2 Calculations Table 2.3S-27 summarizes the maximum relative concentration and relative deposition (i.e., χ/Q and D/Q) values predicted by the XOQDOQ model for identified sensitive receptors of interest in the STP site area due to routine releases of gaseous effluents. The listed maximum χ/Q values reflect several plume depletion scenarios that account for radioactive decay: no decay and the default half-life decay periods of 2.26 and 8 days. The no decay and 2.26 day decay χ/Q values assume no dry deposition and the 8 day decay χ/Q values assume dry deposition.
The overall maximum annual average χ/Q value with no decay is 8.3E-05 sec/m3 and occurs at the Unit 4 Reactor Building due to the releases from the Unit 3 Reactor Building. The maximum annual average χ/Q values with no decay (along with the direction and distance of the receptor locations relative to the STP site) for the other sensitive receptor types are:
3 6.3E-07 sec/m for the nearest resident occurring in the WSW sector at a distance of 2.18 miles.
3 6.3E-07 sec/m for the nearest vegetable garden and meat animal occurring in the WSW sector at a distance of 2.18 miles.
3 8.1E-06 sec/m for the nearest site boundary occurring in the NNW sector at a distance of 0.69 mi.
Tables 2.3S-28 and 2.3S-29 summarize the annual average χ/Q values (for no decay) and D/Q values for 22 standard radial distances between 0.25 mile and 50 miles, and for 10 distance-segment boundaries between 0.5 mile and 50 miles downwind along each of the 16 standard direction radials separated by 22.5°.
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2.3S.6 References 2.3S-1 “2005 Local Climatological Data, Annual Summary with Comparative Data, Victoria, Texas,” National Climatic Data Center (NCDC), NESDIS, NOAA, 2006.
2.3S-2 “Climatography of the United States, No. 20, 1971-2000, Monthly Station Climate Summaries,” NCDC, CD-ROM, NESDIS, NOAA, July 2005.
2.3S-3 “Climatography of the United States, No. 81, 1971-2000, U.S. Monthly Climate Normals,” NCDC, CD-ROM, National Environmental Satellite, Data and Information Service (NESDIS), NOAA, February 2002.
2.3S-4 “Cooperative Summary of the Day, TD3200, Period of Record (POR) through 2001 (Includes Daily Weather Data from the Central United States),” NCDC, Version 1.0 (CD-ROM), data listings Danevang 1W, Aransas WR, Matagorda 2, Edna Highway 59 Bridge, and Thompsons 3 WSW, NOAA, June 2002.
2.3S-5 “U.S. Summary of Day Climate Data (DS 3200/3210), POR 2002-2005,” NCDC, CD-ROM, NOAA, July 2006.
2.3S-6 Standard Review Plan, NUREG-0800, Revision 3, Local Meteorology, March 2007.
2.3S-7 Solar and Meteorological Surface Observation Network, 1962-1999, Volume II, Central U.S, National Climate Data Center – National Renewal Energy Lab, 1993.
2.3S-8 ”Hourly United States Weather Observations,” NCDC 1990-1995, CD- ROM, NCDC, National Oceanic and Atmospheric Administration (NOAA), October 1997.
2.3S-9 “2005 ASHRAE Handbook – Fundamentals, Chapter 28, Climatic Design Information,” American Society of Heating, Refrigerating, and Air- Conditioning Engineers, Atlanta, Georgia, 2005.
2.3S-10 ASCE Standard ASCE/SEI-7-05, Minimum Design Loads for Buildings and Other Structures, American Society of Civil Engineers (ASCE) and Structural Engineering Institute, 2005.
2.3S-11 “Seasonal Variation of 10-Square Mile Probable Maximum Precipitation Estimates, United States East of the 105th Meridian,” NRC, NUREG/CR- 1486, Hydrometerological Report No. 53, June 1980.
2.3S-12 “Coastal Services Center, Historical Hurricane Tracks Storm query, 1851 through 2005,” NOAA, National Ocean Service. Available at http://hurricane.csc.noaa.gov/hurricanes/viewer.html, accessed June 29, 2007.
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2.3S-13 “The Climatic Atlas of the United States,” NCDC, Version 2.0 (CD-ROM), NCDC, Climate Services Division, NOAA, September 2002.
2.3S-14 “Storm Events for Texas, Hail Event, and snow and Ice Event Summaries,” NCDC, NOAA. Available at http://wwwr.ncdc.noaa.gov/cgi- win/wwcgi.dll?wwEvent~Storms, accessed June 2007.
2.3S-15 “Storm Data (and Unusual Weather Phenomena with Late Reports and Corrections), January 1959 (Volume 1, Number 1) to January 2004 (Volume 46, Number 1),” NCDC, complete set of monthly hardcopy issues purchased as PDF files on CD-ROM from NCDC, NCDC, NESDIS, NOAA, June 2004.
2.3S-16 “Climatology for the United States (1948-1998),” Wang, J.X.L., and J.K. Angell, Air Stagnation NOAA Air Resources Laboratory Atlas No. 1, Air Resources Laboratory, Environmental Research Laboratories, Office of Oceanic and Atmospheric Research, Silver Spring, Maryland, April 1999.
2.3S-17 “Climatography of the United States, No. 85, Divisional Normals and Standard, Deviations of Temperature, Precipitation, and Heating and Cooling Degree Days, 1971-2000 (and previous normal periods), Section 1 (Temperature) and Section 2 (precipitation),” NCDC, NESDIS, NOAA, June 15, 2002.
2.3S-18 “Design Basis Tornado and Tornado Missiles for Nuclear Power Plants,” RG 1.76, Revision 1, March 2007.
2.3S-19 “Tornado Climatology of the Contiguous United States,” NUREG/CR-4461, (PPNL-15112, Rev.1) February 2007.
2.3S-20 “Texas Climate for Angleton 2W, Aransas WR, Bay City Waterworks, Danevang 1W, Freeport 2NW, Palacios Municipal AP, Pierce 1E, Point Comfort, Port O’Connor, Thompsons 3 WSW, and Victoria Regional Airport,” Utah State University, Utah Climate Center, 2007. Available at http://climate.usurf. usu.edu/, accessed May 23, 2007.
2.3S-21 National Climatic Data Center, Cooperative Select Station, Cooperative Select Form, Texas, Port O’Connor, 2006-07, NCDC, NOAA, Available at http://www7.ncdc.noaa.gov/IPS/statuscooppdf.html, accessed May 22, 2007.
2.3S-22 “Climatology of the United States No. 60, Texas Climatology,” NCDC, Available athttp://www5.ncdc.noaa.gov/climatenormals/clim60/ states/Clim_Texas_01.pdf, accessed June 29, 2007.
2.3S-56 Meteorology Rev. 12
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2.3S-23 “Weather World 2010, the Online Guides for Meteorology – Precipitation,” University of Illinois at Urbana-Champaign (UIUC). Available at http://ww2010.atmos.edu (Gh)/guides/mtr/cld/prep/home.rxml, accessed June 27, 2007.
2.3S-24 “Summary of Items of Engineering Interest,” U.S. Department of Agriculture Rural Utilities Service, Rural Utilities Service, RUS Technical Publication 1998.
2.3S-25 Ten-year U.S. Flash Density, 1989-1999 Average U.S. Flashes/km2/yr, http://www.nssl.noaa.gov/primer/lightning/imags/ltgflash_density.jpg.acce ssed July 18, 2007.
2.3S-26 Ventilation Database of Mean Monthly AM and PM Mixing Heights and Wind speed; http://airfire.org/vcis-cgi/graphics.htm, accessed April 13, 2007.
2.3S-27 National Climatic Data Center, Integrated Surface Hourly Data, 1995-1999, CDROM, Volume 8, Central United States of America, NCDC, NESDIS, NOAA, September 2002.
2.3S-28 “Meteorological Monitoring Programs for Nuclear Power Plants,” RG 1.23, Revision 1, March 2007.
2.3S-29 “Standard Review Plans for Environmental Reviews for Nuclear Power Plants,” NRC, NUREG-1555, October 1999.
2.3S-30 40 CFR, 1.38 Metropolitan. Houston-Galveston Intrastate Air Quality Control Region, 62 FR 30272, June 3, 1997.
2.3S-31 40 CFR Protection of the Environment, Part 50 - National Ambient Primary and Secondary Ambient Air Quality Standards for Criteria Pollutants, 2007.
2.3S-32 40 CFR 81.344, Designation of Areas for Air Quality Planning Purposes, Attainment Status Designations, Texas.
2.3S-33 40 CFR 81.429, Title 40 Protection of Environment, Part 81.429 Designation of Areas for Air Quality Planning – Texas, Designation of Areas for Air Quality Planning, Subpart D—Identification of Mandatory Class I Federal Areas Where Visibility Is an Important Value. Big Bend National Park and Guadalupe Mountains National Park.
2.3S-34 40 CFR 81.412, Title 40 Protection of Environment, Part 81.412 Designation of Areas for Air Quality Planning – Louisiana, Designation of Areas for Air Quality Planning Purposes, Subpart D—Identification of Mandatory Class I Federal Areas Where Visibility Is an Important Value: Breton Wildlife.
Meteorology 2.3S-57 Rev. 12
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2.3S-35 Texas Commission on Environmental Quality (TCEQ), Air Permit Search Database (Title V and New Source Review). Available at http://www2.tceq. state.tx.us/airpermit/index.ctm, accessed July 16, 2007.
2.3S-36 “Combined License Applications for Nuclear Power Plants (LWR Edition),” RG 1.206, Revision 0, June 2007.
2.3S-37 ANS/ANSI American National Standard for Determining Meteorological Information at Nuclear Facilities, ANS/ANSI 3.11- 2005, December 2005.
2.3S-38 “Instrumentation for Light-Water-Cooled Nuclear Power Plants to Assess Plant and Environs Conditions During and Following An Accident,” RG 1.97, Revision 3, May 1983.
2.3S-39 “Measuring, Evaluating, and Reporting Radioactivity in Solid Wastes and Releases of Radioactive Materials in Liquid and Gaseous Effluents from Light-Water-Cooled Nuclear Power Plants,” NRC, RG 1.21, Revision 1, June 1974.
2.3S-40 STPEGS Updated Safety Analysis Report, Units 1 and 2, Revision 13.
2.3S-41 “Functional Criteria for Emergency Response Facilities,” NUREG-0696, Final Report, February 1981.
2.3S-42 “Clarification of TMI Action Plan Requirements,” NUREG-0737, Final Report, November 1980.
2.3S-43 “Criteria for Preparation and Evaluation of Radiological Emergency Response Plans and Preparedness in Support of Nuclear Power Plants,” NUREG-0654, Revision 1, Appendix 2, FEMA-REP-1, March 2002.
2.3S-44 “Criteria for Accident Monitoring Instrumentation for Nuclear Power Plants,” RG 1.97, Revision 4, June 2006.
2.3S-45 “Method for Estimating Atmospheric Transport and Dispersion of Gaseous Effluents in Routine Releases from Light-Water-Cooled Reactors,” RG 1.111, Revision 1, July 1977.
2.3S-46 10 CFR 100, Title 10, Energy, Part 100, Reactor Site Criteria.
2.3S-47 “Atmospheric Dispersion Models for Potential Accident Consequence Assessments at Nuclear Power Plants,” RG 1.145, Revision 1, November 1982 (Reissued February 1983).
2.3S-48 NRC, PAVAN: An Atmospheric Dispersion Program for Evaluating Design Basis Accidental Releases of Radioactive Materials from Nuclear Power Stations, NUREG/CR-2858, PNL-4413, November 1982.
2.3S-49 Not Used.
2.3S-58 Meteorology Rev. 12
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2.3S-50 “Atmospheric Relative Concentrations in Building Wakes,” NUREG/CR 6331, Revision 1, May 1997.
2.3S-51 “Atmospheric Relative Concentrations for Control Room Radiological Habitability Assessments at Nuclear Power Plants,” RG 1.194, June 2003.
2.3S-52 “Assumptions for Evaluating the Habitability of a Nuclear Power Plant Control Room During a Postulated Hazardous Chemical Release,” RG 1.78, Revision 1, December 2001.
2.3S-53 NRC, XOQDOQ: Computer Program for the Meteorological Evaluation of Routine Effluent Releases at Nuclear Power Stations, NUREG/CR-2919, September 1982.
2.3S-54 Offsite Dose Calculation Manual (ODCM), Revision 15, South Texas Project.
2.3S-55 "TX068.46 Clean Air Act Reclassification of the Houston/Galveston/ Brazoria Ozone Nonattainment Area; Texas; Final Rule" Code of Federal Regulations Title 40, Pt. 81, (1 October 2008) p. 56983-56995. [Available at http://www.regulations.gov].
2.3S-56 “Designation of Areas for Air Quality Planning Purposes”. Code of Federal Regulations, Title 40, Pt. 81, Subpart C, Section 107. Accessed on December 9, 2008. [Available at http://ecfr.gpoaccess.gov].
2.3S-57 National Climatic Data Center, Climate Data Online, Surface Data, Monthly, NCDC, NOAA, Available at http://cdo.ncdc.noaa.gov/cgi-bin/cdo/cdostnsearch.pl, accessed November 20, 2008.
2.3S-58 National Climatic Data Center, Climate Data Online, Surface Data, Daily - US, Data Access, NCDC, NOAA, http://cdo.ncdc.noaa.gov/CDO/cdo, accessed November 24, 2008.
2.3S-59 NOAA Central Library U.S. Daily Weather Maps Project NCDC, NOAA, http://www.hpc.ncep.noaa.gov/dwm/dwm.shtml, accessed December 9, 2008.
2.3S-60 References Manual, WBAN Hourly Surface Observations 144, National Climatic Data Center, Revised, November 1970.
2.3S-61 National Climatic Data Center, Integrated Surface Hourly Data, 1995-99, CD-ROM, Volume 8, Central United States of America, NCDC, NESDIS, NOAA, September 2002.
2.3S-62 National Climatic Data Center. Integrated Surface Hourly Observations, 2000, CDROM, Volume 15, United States of America, NCDC, NESDIS, NOAA, September 2002.
Meteorology 2.3S-59 Rev. 12
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2.3S-63 National Climatic Data Center. Integrated Surface Hourly Observations, 2001, CDROM, Volume 19, United States of America, NCDC, NESDIS, NOAA, January 2003.
2.3S-64 National Climatic Data Center. Integrated Surface Hourly Observations, 2002, CDROM, Volume 23, United States of America, NCDC, NESDIS, NOAA, August 2003.
2.3S-65 National Climatic Data Center. Integrated Surface Hourly Observations, 2003, DVDROM, Global Data Set, United States of America, NCDC, NESDIS, NOAA, October 2004.
2.3S-66 National Climatic Data Center. Integrated Surface Hourly Observations, 2004, DVDROM, Global Data Set, United States of America, NCDC, NESDIS, NOAA, June 2005.
2.3S-67 National Climatic Data Center. Integrated Surface Hourly Observations, 2005, DVDROM, Global Data Set, United States of America, NCDC, NESDIS, NOAA, August 2006.
2.3S-68 Palacios Municipal Airport, Quality Controlled Local Climatological Data,1988-1994, 2006 and 2007, National Climatic Data Center.
2.3S-69 Palacios Municipal Airport, Annual Climatological Summary, 2001-2007, National Climatic Data Center.
2.3S-70 Regulatory Guide 1.221, "Design-Basis Hurricane and Hurricane Missiles for Nuclear Power Plants," Revision 0, October 2011.
2.3S-60 Meteorology Rev. 12
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Table 2.3S-1 NWS and Cooperative Observing Stations Near the STP 3 & 4 Site Approximate Distance Direction Station [1] County (miles) Relative to Site Elevation (feet) Matagorda 2 Matagorda 10 SE 10 Palacios Municipal Airport Matagorda 13 WSW 12 Bay City Waterworks Matagorda 13 NNE 52 Danevang 1W Wharton 20 NNW 70 Maurbro Jackson 26 WNW 30 Pierce 1E Wharton 31 NNW 105 Point Comfort Calhoun 32 WSW 20 Port O’Connor Calhoun 34 SW 5 Wharton Wharton 36 N 111 Edna Highway 59 Bridge Jackson 40 WNW 68 Freeport 2NW Brazoria 43 ENE 8 Angleton 2W Brazoria 44 NE 27 Victoria Regional Airport [2] Victoria 53 W 115 Thompsons 3 WSW Fort Bend 54 NNE 72 Aransas Wildlife Refuge Aransas 56 SW 15 NOTES:
[1] Numeric and letter designators following a station name (e.g., Pierce 1E) indicate the station’s approximate distance in miles (e.g., 1) and direction (e.g., east) relative to the place name (e.g., Pierce). [2] National Weather Service First-Order Station
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Table 2.3S-2 Local Climatological Data Summary for Victoria, Texas
Source: Reference 2.3S-1
2.3S-62 Meteorology Rev. 12
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Table 2.3S-3 Climatological Extremes at Selected NWS and Cooperative Observing Stations in the STP 3 & 4 Site Area
Maximum Minimum Max 24-Hr Max Monthly Max 24-Hr Max Monthly Temperature Temperature Rainfall Rainfall Snowfall Snowfall Station (°F) (°F) (inches) (inches) (inches) (inches)
Matagorda 2 104 [a] 9 [a] 15.71 [a] 20.75 [a] 5.0 [c] 5.0 [c] (09/06/00) (12/23/89) (05/01/11) (10/86) (12/25/04) (12/04) Palacios Muni Airport 107 [a] 9 [a] 9.65 [a] 24.28 (10/49) 4.0 [b, d] 4.0 [b, d] (09/05/00) (12/23/89) (05/07/51) [1] (02/12/58) (02/58) Bay City Waterworks 109 [a, b] 7 [a, b] 20.85 24.02 (10/83) 3.8 [b, d] 3.8 [b, d] (09/06/00) [g] (12/24/89) [h] (10/19/83) [1] [1] (02/12/58) (02/58) Danevang 1W 109 [a, b] 7 [a] 12.96 [a] 24.01 [b, d] 10.5 [n] 10.5 [n] (09/06/00) [i] (01/23/40) (06/26/60) (08/45) (12/25/04) (12/04) Maurbro 107 [b, d] 8 [b, d] 14.80 [b, d] 22.47 [b, d] 4.0 [b, d] 4.0 [b, d] (07/27/54) (01/31/49) (06/26/60) (06/60) (02/13/60) (02/60) Pierce 1E 112 [a] 4 [a] 8.85 [a] 23.37 8.0 b, [d] 8.0 [b, d] (09/05/00) (01/31/49) (11/02/43) (11/04) [1] (02/13/60) (02/60) Point Comfort 107 [a] 9 [a] 14.65 [a] 25.24 [b, d] Trace [a] Trace [a] (09/06/00) (12/23/89) (06/26/60) (06/60) (11/28/76) (11/76) Port O’Connor 105 [a] 10 [a] 12.50 [a] 24.51 (10/84) 1.3 [a] 1.3 [a] (09/06/00) (12/23/89) (07/10/76) [1] (02/09/73) (02/73) Wharton NA [f] NA [f] 20.06 (11/04) 7.0 [b, d] 7.0 [b, d] 11.58 [1] (02/13/60) (02/60) (10/18/94) [1] Edna Hwy 59 Bridge 105 [1] 17 [1] 17.58 [b, d] 20.97 [b, d] NA [f] NA [f] 8/12/69 01/12/73 (10/18/94) (10/94) Freeport 2NW 105 [a, b] 13 [a] 16.72 [a] 31.61 [a] 2.0 b, [d] 3.0 b, [d] (09/06/00) [g] (12/26/83) (07/26/79) (09/79) (02/12/58) (01/40) Angleton 2W 107 [a] 7 [a, b] 14.36 [a] 22.13 [a] 3.0 [b, d] 3.0 [b, d] (09/05/00) (12/24/89) [h] (07/26/79) (07/79) (01/22/40) (01/40) Victoria Regional 111 [a] 9 [a] 9.87 [a] 19.05 [a] 3.4 [1] (02/58) Airport (09/05/00) (12/23/89) (04/05/91) (09/78) 3.3 [m] (02/12/58) Thompsons 3WSW 106 [c] 8 [a] 9.53 [a] 18.15 [b, d] 1.5 [a, b, d] 1.5 [a, b, d] (07/07/05) (12/23/89) (09/19/83) (06/60) (02/09/73) [j] (02/73) [j] Aransas Wildlife 102 [a, b] 9 [a] 14.25 [a] 19.08 [a] 5.5 [c] 5.5 [c] Refuge (09/06/00) [k] (12/23/89) (11/01/74) (09/79) (12/25/04) (12/04)
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Notes: [a] Reference 2.3S-2 [b] Reference 2.3S-4 [c] Reference 2.3S-5 [d] Reference 2.3S-3 [e] Reference 2.3S-21 [f] NA = Measurements not made at this station [g] Occurs on multiple dates: 09/04/00; 09/06/00 (most recent date shown in table) [h] Occurs on multiple dates: 12/23/89; 12/24/89 (most recent date shown in table) [i] Occurs on multiple dates: 09/05/00; 09/06/00 (most recent date shown in table) [j] Occurs on multiple dates: 02/13/60; 02/09/73 (most recent date and/or month shown in table) [k] Occurs on multiple dates: 05/03/84; 05/04/84; 09/06/00 (most recent date shown in table) [l] Reference 2.3S-57 [m] Reference 2.3S-58 [n] Reference 2.3S-20
2.3S-64 Meteorology Rev. 12
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Table 2.3S-4 Morning and Afternoon Mixing Heights and Wind Speeds for the STP Site Area Mixing Height (m, AGL) [2] Wind Speed – (m/sec) Period Statistic [1] AM PM AM PM January Min 267 554 3.2 2.9 Max 550 1004 4.9 4.2 Mean 416 843 4.2 3.7 February Min 294 717 3.1 2.9 Max 582 1227 5 4.3 Mean 429 979 4.2 3.7 March Min 283 872 3.7 3.1 Max 773 1478 5.1 4.7 Mean 521 1127 4.5 4.0 April Min 302 836 4.0 3.4 Max 892 1577 5.3 4.7 Mean 615 1147 4.7 4.1 May Min 378 859 3.6 2.6 Max 909 1574 5.8 4.7 Mean 608 1224 4.7 3.9 June Min 209 1056 3.7 2.7 Max 1036 1850 5.5 4.1 Mean 469 1418 4.4 3.6 July Min 191 1095 3.4 2.9 Max 602 1904 5.2 4.2 Mean 351 1518 4.1 3.5 August Min 193 1181 2.8 2.7 Max 606 2005 4.8 4.2 Mean 340 1570 3.9 3.5 September Min 174 1122 3.1 2.8 Max 614 1737 5.0 4.4 Mean 346 1390 3.8 3.5 October Min 197 972 2.9 2.6 Max 530 1724 5.0 4.2 Mean 333 1282 3.9 3.5 November Min 278 741 3.3 2.9 Max 582 1342 4.9 4.4 Mean 399 1051 4.2 3.7 December Min 267 577 3.5 2.6 Max 593 1102 5.1 4.2 Mean 392 853 4.2 3.7
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Table 2.3S-4 Morning and Afternoon Mixing Heights and Wind Speeds for the STP Site Area (Continued) Mixing Height (m, AGL) [2] Wind Speed – (m/sec) Period Statistic [1] AM PM AM PM Winter Mean 412 892 4.2 3.7 Spring Mean 581 1166 4.6 4.0 Summer Mean 387 1502 4.1 3.5 Autumn Mean 359 1241 4.0 3.6 Annual Mean 435 1200 4.2 3.7 Sources: USDA-Forest Service 2007 (Reference 2.3S-26) Notes:
[1] Monthly minimum, maximum and mean values are based directly on summaries available from USDA - Forest Service Ventilation Climate Information System (VCIS) (Reference 2.3S-26) (USDA 2007). Seasonal and annual mean values represent weighted averages based on the number of days in the appropriate months. [2] AGL = above ground level
2.3S-66 Meteorology Rev. 12
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Table 2.3S-5 Climatological Normals at Selected NWS and Cooperative Observing Stations in the STP 3 & 4 Site Area Normal Annual Normal Annual Temperatures (OF) [1] Precipitation Daily Daily Daily Daily Rainfall [1] Snowfall [2] Station Maximum Minimum Range Mean (inches) (inches) Matagorda 2 77.5 61.8 15.7 69.7 43.75 0.1 Palacios Muni Airport 77.2 61.1 16.1 69.2 45.40 0.1 Bay City Waterworks 80.6 61.2 19.4 70.9 48.03 0.0 Danevang 1W 79.0 58.5 20.5 68.8 45.37 0.2 Maurbro [3] ––––– – Pierce 1E 79.7 58.0 21.7 68.9 45.92 Trace Point Comfort 79.7 62.4 17.3 71.1 43.87 Trace Port O’Connor 76.4 65.0 11.4 70.7 34.78 0.1 Wharton – – – – 45.62 – Edna Hwy 59 Bridge – – – – 42.17 – Freeport 2NW 77.6 62.1 15.5 69.8 50.66 Trace Angleton 2W 78.5 59.9 18.6 69.2 57.24 0.1 Victoria Regional Airport 79.6 60.4 19.2 70.0 40.10 0.3 Thompsons 3WSW 79.6 59.3 20.3 69.5 45.81 0.1 Aransas Wildlife Refuge 77.5 62.9 14.6 70.2 40.83 Trace
[1] Reference 2.3S-3 [2] Reference 2.3S-2 [3] Station decommissioned in 1966
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Table 2.3S-6 Seasonal and Annual Mean Wind Speeds for the STP 3 & 4 Site (1997, 1999, and 2000) and the Victoria, Texas NWS Station (1971–2000, Normals) Primary Tower Elevation Location Winter Spring Summer Autumn Annual Upper Level STP 3 & 4 Site 6.5 6.5 5.4 5.6 6.0 (60 m) (m/sec) Lower Level STP 3 & 4 Site 4.5 4.7 3.7 3.6 4.1 (10 m) (m/sec) Single Level Victoria Regional 4.6 4.8 3.9 3.9 4.3 (6.1 m) (m/sec) Airport [1] Notes: Winter = December, January, February Spring = March, April, May Summer = June, July, August Autumn = September, October, November
[1] Reference 2.3S-1
2.3S-68 Meteorology Rev. 12
STP 3 & 4 Final Safety Analysis Report 96 254 82 221 Direction Direction Direction Direction Sensor: 1 Speed Greater than or Equal than or Equal to:5.00 mph Greater Speed Speed Greater than or Equal to:10.00 mph to:10.00 or Equal than Speed Greater mph to:15.00 or Equal than Speed Greater Period of Record: 1/1/1997 00:00 to 12/31/1997 23:00 and 1/1/1999 00:00 to 12/31/2000 23:00 to 00:00 12/31/2000 and 23:00 1/1/1999 to 00:00 12/31/1997 of Record: 1/1/1997 Period Width in Degrees: 22.5 Speed Sensor: 1 Table 2.3S-7 Wind Direction Persistence/Wind Speed Distributions for the STP 3 & 4 Site – 10-Meter Level 10-Meter 3 & 4 Site – STP for the Speed Distributions Direction Persistence/Wind Wind 2.3S-7 Table Hours N1 NNE2 8494 575 455 303 NE 259 110 275 ENE 137 33 295 163 E 68 475Hours N ESE 3021 NNE 313 156 823 534 SE 93 NE 1563 267 1075 SSE ENE 1744 28 578 1188 1685 S 1200 E 629 57 WSW 455 ESE 286 637 170 SW 188 SE 122 285 96 WSW 47 SSE 402 23 10 W 24 396 WNW S 0 5 WSW 200 59 NW 29 1 NNW SW 57 244 WSW 157 10 655 33 440 W 7 WNW NW 7 NNW 12 Site STP Name: Site Number of Sectors Included: 1 Measurement Height, m: 10 18544623004821637115 637 2370 420 3068 010 HoursN 02 1 00 NNE 15322 00 10074 1342 00 815885143476126320405418625116 01 534 828 NE1255290103048126137142220000 354 9961835039733232490000 2400001085330000 ENE 5233000000010000000 162 8353600000000000000 4800000000000000 412 E 716 1123 144 601 ESE 00 1607 261 00 00 932 2951 00 SE889330265785191199175330001 419122590102927747745180000 1931 3368180003902519380000 SSE2400001085020000 999 04 22743000000010000000 31823600000000000000 1228 S4800000000000000 2313 1195 WSW 1329 00 709 499 00 00 SW 282219744831116193252240127381313562155 00 24848418015639911911355211010 172 00 8930522312320840000 WSW12000110615100000 631800002000000000 170 622400000000000000 W3000000000000000 13 2433600000000000000 66 WNW4800000000000000 15 529 109 NW 1110 NNW 39 311 723 138 362
Meteorology 2.3S-69 Rev. 12
STP 3 & 4 Final Safety Analysis Report Direction Direction Direction Direction Sensor: 1 Sensor: Direction Speed Greater than or Equal to:20.00 mph to:20.00 Equal or than Greater Speed Speed Greater than or Equal to:25.00 mph to:25.00 Equal or than Greater Speed mph to:30.00 Equal or than Greater Speed Speed Sensor: 1 Sensor: Speed Period of Record: 1/1/1997 00:00 to 12/31/1997 23:00 and 1/1/1999 00:00 to 12/31/2000 23:00 to 12/31/2000 00:00 1/1/1999 and 23:00 12/31/1997 to 00:00 Record: 1/1/1997 of Period Width in Degrees: 22.5 in Degrees: Width Table 2.3S-7 Wind Direction Persistence/Wind Speed Distributions for the STP 3 & 4 Site – 10-Meter Level (Continued) 10-Meter Level STP 3 & 4 Site – for the Speed Distributions Persistence/Wind Direction Wind 2.3S-7 Table Site Name: STP Name: Site 1 Included: of Sectors Number m: 10 Height, Measurement 4104319342 1455 531 00 00 00 HoursN 010 00 145110144351391314120 03 00 NNE2220009232616701010 00 450005862400000 800001100000000 1200000000000000 NE1800000000000000 2400000000000000 3000000000000000 ENE3600000000000000 4800000000000000 00 E 06 00 HoursN 02 00 00 00 ESE NNE130002474000000 00 00 210001252000000 00 400000030000000 800000000000000 SE NE1200000000000000 1800000000000000 2400000000000000 SSE ENE3000000000000000 3600000000000000 4800000000000000 00 S E 00 00 00 00 HoursN WSW 00 00 ESE100000020000000 00 00 NNE200000000000000 00 400000000000000 SW800000000000000 SE1200000000000000 NE1800000000000000 WSW2400000000000000 SSE3000000000000000 ENE3600000000000000 4800000000000000 W S WNW E WSW ESE NW SW NNW SE WSW SSE W WNW S WSW NW SW NNW WSW W WNW NW NNW
2.3S-70 Meteorology Rev. 12
STP 3 & 4 Final Safety Analysis Report 97 383 Direction Direction Direction Direction Sensor: 2 Sensor: Direction Speed Greater than or Equal to:5.00 mph to:5.00 or Equal than Greater Speed Speed Greater than or Equal to:15.00 mph to:15.00 Equal or than Greater Speed Speed Greater than or Equal to:10.00 mph to:10.00 Equal or than Greater Speed Period of Record: 1/1/1997 00:00 to 12/31/1997 23:00 and 1/1/1999 00:00 to 12/31/2000 23:00 12/31/2000 00:00 to and 1/1/1999 23:00 12/31/1997 to 00:00 1/1/1997 Record: of Period Speed Sensor: 2 Sensor: Speed Width in Degrees: 22.5 in Degrees: Width Table 2.3S-8 Wind Direction Persistence/Wind Speed Distributions for the STP 3 & 4 Site – 60-Meter Level 60-Meter 3 & 4 Site – STP for the Speed Distributions Direction Persistence/Wind Wind 2.3S-8 Table HoursN 00 1 1363 00 NNE2 00 9714 1009 573822964314470142309553442701001137118 12101163251953121206164110000731 633 NE183700167104353280000001 276 783241000101016840000000 3030040000000000 ENE 4603600000000000000 185 7144800000000000000 419 E 170 982 00 630919HoursN 00 1 00 768 ESE NNE2 1429 296 00 517 18144283994860972083825935341301203146195 8972033527741282211721600001267 4321236302442451976340000014 2588 251 SE NE 2611 44618110015031222120000000 2430090055200000 275 35203000030000000000 2207 ENE SSE 1433600000000000000 9694800000000000000 2936 233 672 1546 132 E S 1033 367 1282 184 WSW 213 ESE 346 597 308 SW 384 47 SE 118 986 WSW 62 676 SSE 43 1471 99 1045 W 8 43 S 1387 WNW 84 988 WSW 217 471 13 299 NW 354 SW 132 NNW 657 15 950 WSW 65 26 108 W 3 349 37 WNW 14 20 NW NNW 6 165 576 HoursN 00 1 1658 00 NNE2 1140 00 4 1347 648825478395377150438674539771411646132 818121131852819531872452021300001034 NE184000167105155360000003 1120 356241000101016860000000 3030040000000000 620 ENE 10383600000000000000 2374800000000000000 547 1353 E 213 1835 791 ESE 346 3170 1147 SE 524 4159 2235 SSE 1238 3600 3087 1855 1372 2695 S 1571 WSW 529 855 366 SW 222 270 WSW 88 225 81 W 17 304 86 WNW 18 568 158 1173 NW 52 NNW 345 784 167 409 Site Name: STP Site 1 Included: of Sectors Number m: Height, 60 Measurement
Meteorology 2.3S-71 Rev. 12
STP 3 & 4 Final Safety Analysis Report 60 234 Direction Direction Direction Direction Sensor: 2 Sensor: Direction Speed Greater than or Equal to:25.00 mph to:25.00 Equal or than Greater Speed mph to:30.00 Equal or than Greater Speed Speed Greater than or Equal to:20.00 mph to:20.00 Equal or than Greater Speed Period of Record: 1/1/1997 00:00 to 12/31/1997 23:00 and 1/1/1999 00:00 to 12/31/2000 23:00 12/31/2000 00:00 to and 1/1/1999 23:00 12/31/1997 to 00:00 1/1/1997 Record: of Period Speed Sensor: 2 Sensor: Speed Width in Degrees: 22.5 in Degrees: Width Table 2.3S-8 Wind Direction Persistence/Wind Speed Distributions for the STP 3 & 4 Site – 60-Meter Level (Continued) 60-Meter Level STP 3 & 4 Site – for the Speed Distributions Persistence/Wind Direction Wind 2.3S-8 Table 2003600002 00 00 HoursN 00 1 00 241 NNE2148215194512314725421275807034149 00 4696081960751151013210201467 8800031415252360000119 601200000306400000 NE1800000000000000 2400000000000000 3000000000000000 ENE 203600000000000000 4800000000000000 00 37 00 E 00 HoursN 00 145310122277551208050765 03 00 ESE NNE2250000910332993020331 80 00 4800002051610000113 800000000600000 1200000000100000 SE NE 1911800000000000000 2400000000000000 3000000000000000 SSE ENE3600000000000000 2334800000000000000 00 410 00 S E 07 00 HoursN 03 00 15000035131012020011 WSW 00 00 ESE 335 NNE210000125501000 00 400000001300000 800000000000000 SW1200000000000000 139 SE NE1800000000000000 2400000000000000 WSW3000000000000000 ENE SSE 253600000000000000 4800000000000000 W E S 3 WNW WSW ESE 16 NW SW SE NNW WSW 4 SSE W S WNW WSW NW SW NNW WSW W WNW NW NNW Site Name: STP Site 1 Included: of Sectors Number m: Height, 60 Measurement
2.3S-72 Meteorology Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.3S-9 Seasonal and Annual Vertical Stability Class and 10-Meter Level Wind Speed Distributions for the STP 3 & 4 Site (1997, 1999, and 2000) Vertical Stability Categories [1] PeriodABCDEFG Winter Frequency (%) 9.25 3.85 5.07 33.13 28.52 9.65 10.52 Wind Speed 5.95.55.45.44.22.82.0 (m/sec) Spring Frequency (%) 11.63 6.43 7.27 39.27 24.12 6.70 4.57 Wind Speed 6.15.55.65.43.72.31.9 (m/sec) Summer Frequency (%) 19.74 5.62 6.44 20.02 32.27 13.05 2.87 Wind Speed 4.84.34.34.23.41.81.5 (m/sec) Fall Frequency (%) 14.33 5.32 4.57 22.04 23.35 13.28 17.10 Wind Speed 4.54.64.94.83.42.31.9 (m/sec) Annual Frequency (%) 13.73 5.31 5.85 28.67 27.07 10.65 8.72 Wind Speed 5.25.05.15.13.72.31.9 (m/sec)
[1] Vertical stability based on temperature difference (DT) between 60-meter and 10-meter measurement levels.
Meteorology 2.3S-73 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.3S-10 Joint Frequency Distribution of Wind Speed and Wind Direction (10-Meter Level) by Atmospheric Stability Class for the STP 3 & 4 Site (1997, 1999, and 2000)
Hours at Each Wind Speed and Direction
Period of Record: 1997, 1999, 2000 Total Period
Elevation: Speed: PT SPD10 Direction: PT DIR10 Lapse:PT DT60-10
Stability Class:AΔT Extremely Unstable
Wind Speed (m/s) Wind Direction 0.23- 0.51- 0.76- 1.1- 1.6- 2.1- 3.1- 5.1- 7.1- 10.1- 13.1- (from) 0.50 0.75 1.00 1.5 2.0 3.0 5.0 7.0 10.0 13.0 18.0 > 18.0 Total N 0 0 0 1 6154029190 0 0110 NNE 0 0 0 1 42039274 0 0 0 95 NE 0 0 0 2 32558193 0 0 0110 ENE 0 0 0 1 412389 3 0 0 0 67 E 0 0 0 0 2112714110 0 0 65 ESE 0 0 0 0 5 9 36 38 37 0 0 0 125 SE 0 0 0 0 311114144632 0 0337 SSE 0 0 0 0 113119186861 0 0406 S 0 0 0 0 4 46 450 588 79 2 0 0 1169 SSW 0 0 0 0 739206140370 0 0429 SW 0 0 0 1 2347243180 0 0170 WSW 0 0 0 0 610136 5 0 0 0 40 W 0 0 0 0 411164 3 0 0 0 38 WNW 0 0 0 2 33126163 0 0 0 81 NW 0 0 0 2 5152532170 0 0 96 NNW 0 0 0 1 1225245321 0 0154
Totals 0 0 0 11 60 324 1331 1340 420 6 0 0 3492
Number of Calm Hours for this Table 0 Number of Variable Direction Hours for this Table 0 Number of Invalid Hours 879 Number of Valid Hours for this Table 3492 Total Hours for the Period 26304
Note: Stability class based on the vertical temperature difference (ΔT or lapse rate) between the 60-meter and 10-meter measurement levels.
2.3S-74 Meteorology Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.3S-10 Joint Frequency Distribution of Wind Speed and Wind Direction (10-Meter Level) by Atmospheric Stability Class for the STP 3 & 4 Site (1997, 1999, and 2000) (Continued)
Hours at Each Wind Speed and Direction
Period of Record: 1997, 1999, 2000 Total Period
Elevation: Speed: PT SPD10 Direction: PT DIR10 Lapse: PT DT60-10F
Stability Class:BΔT Moderately Unstable
Wind Speed (m/s) Wind Direction 0.23- 0.51- 0.76- 1.1- 1.6- 2.1- 3.1- 5.1- 7.1- 10.1- 13.1- (from) 0.50 0.75 1.00 1.5 2.0 3.0 5.0 7.0 10.0 13.0 18.0 > 18.0 Total N 0 0 0248219900 053 NNE 0 0 0 0 2 8 29 10 4 0 0 0 53 NE 0 0 0 0 214269 1 0 0 0 52 ENE 0 0 0228249100 046 E 0 0 0126157510 037 ESE 0 0 0 0 4 4 29 45 23 2 0 0 107 SE 0 0 0 0 11473100480 0 0236 SSE 0 0 0 1 6188690270 0 0228 S 0 0 0 1 3 20 140 80 19 0 0 0 263 SSW 0 0 0 0 01837114 0 0 0 70 SW 0 0 0 0 3 7 12 11 2 0 0 0 35 WSW 0 0 0021091000 022 W 0 0 002632110 015 WNW 0 0 1021561300 028 NW 0 0 0 2 1 6 11 13 8 0 0 0 41 NNW 0 0 0 2 1101724101 0 0 65
Totals 0 0 1 11 37 172 538 422 165 5 0 0 1351
Number of Calm Hours for this Table 0 Number of Variable Direction Hours for this Table 0 Number of Invalid Hours 879 Number of Valid Hours for this Table 1351 Total Hours for the Period 26304
Note: Stability class based on the vertical temperature difference (ΔT or lapse rate) between the 60-meter and 10-meter measurement levels.
Meteorology 2.3S-75 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.3S-10 Joint Frequency Distribution of Wind Speed and Wind Direction (10-Meter Level) by Atmospheric Stability Class for the STP 3 & 4 Site (1997, 1999, and 2000) (Continued)
Hours at Each Wind Speed and Direction
Period of Record: 1997, 1999, 2000 Total Period
Elevation: Speed: PT SPD10 Direction: PT DIR10 Lapse:PT DT60-10
Stability Class:CΔT Slightly Unstable
Wind Speed (m/s) Wind Direction 0.23- 0.51- 0.76- 1.1- 1.6- 2.1- 3.1- 5.1- 7.1- 10.1- 13.1- (from) 0.50 0.75 1.00 1.5 2.0 3.0 5.0 7.0 10.0 13.0 18.0 > 18.0 Total N 0 0 1 1 4 8 23 23 21 0 0 0 81 NNE 0 0 0 1 31243102 0 0 0 71 NE 0 0 0 2 21144141 0 0 0 74 ENE 0 0 06212337600066 E 0 0 0 0 3162321163 0 0 82 ESE 0 0 0 1 3 9 17 45 39 5 0 0 119 SE 0 0 0 0 5 8 81 123 52 2 0 0 271 SSE 0 0 0 1 01186107241 0 0230 S 0 0 0 0 21794513 0 0 0167 SSW 0 0 0 0 21944113 0 0 0 79 SW 0 0 00311215000040 WSW 0 0 001424000011 W 0 0 0141040000019 WNW 0 0 0251384100033 NW 0 0 2 2 7 7 12 14 7 2 0 0 53 NNW 0 0 0 1 3122523252 0 0 91
Totals 0 0 3 18 49 180 560 462 200 15 0 0 1487
Number of Calm Hours for this Table 0 Number of Variable Direction Hours for this Table 0 Number of Invalid Hours 879 Number of Valid Hours for this Table 1487 Total Hours for the Period 26304
Note: Stability class based on the vertical temperature difference (ΔT or lapse rate) between the 60-meter and 10-meter measurement levels.
2.3S-76 Meteorology Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.3S-10 Joint Frequency Distribution of Wind Speed and Wind Direction (10-Meter Level) by Atmospheric Stability Class for the STP 3 & 4 Site (1997, 1999, and 2000) (Continued)
Hours at Each Wind Speed and Direction
Period of Record: 1997, 1999, 2000 Total Period
Elevation: Speed: PT SPD10 Direction: PT DIR10 Lapse:PT DT60-10
Stability Class:DΔT Neutral
Wind Speed (m/s) Wind Direction 0.23- 0.51- 0.76- 1.1- 1.6- 2.1- 3.1- 5.1- 7.1- 10.1- 13.1- (from) 0.50 0.75 1.00 1.5 2.0 3.0 5.0 7.0 10.0 13.0 18.0 > 18.0 Total N 0 0 1 9 18 67 251 307 157 10 0 0 820 NNE 0 0 1 9 17 67 290 159 48 0 0 0 591 NE 0 0 1 10 19 64 180 75 12 0 0 0 361 ENE 0 0 0101156167111310 0 0386 E 0 0 1 8 14 46 155 183 88 3 0 0 498 ESE 0 0 0 9 13 41 219 223 131 3 0 0 639 SE 0 0 0 10 14 65 371 450 124 6 2 0 1042 SSE 0 0 0 3 11 60 413 391 103 8 0 0 989 S 0 0 0 3 13 60 381 198 21 1 0 0 677 SSW 0 0 0 0 3 36 130 76 3 0 0 0 248 SW 0 0 0 2 31054233 0 0 0 95 WSW 0 0 1139236100044 W 0 0 03716174200049 WNW 0 0 010122228111 0 0 0 84 NW 0 0 0 9 17 42 58 49 43 0 0 0 218 NNW 0 0 1 12 16 46 158 182 117 16 0 0 548
Totals 0 0 6 108 191 707 2895 2448 885 47 2 0 7289
Number of Calm Hours for this Table 0 Number of Variable Direction Hours for this Table 0 Number of Invalid Hours 879 Number of Valid Hours for this Table 7289 Total Hours for the Period 26304
Note: Stability class based on the vertical temperature difference (ΔT or lapse rate) between the 60-meter and 10-meter measurement levels.
Meteorology 2.3S-77 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.3S-10 Joint Frequency Distribution of Wind Speed and Wind Direction (10-Meter Level) by Atmospheric Stability Class for the STP 3 & 4 Site (1997, 1999, and 2000) (Continued)
Hours at Each Wind Speed and Direction
Period of Record: 1997, 1999, 2000 Total Period
Elevation: Speed: PT SPD10 Direction: PT DIR10 Lapse:PT DT60-10
Stability Class:EΔT Slightly Stable
Wind Speed (m/s) Wind Direction 0.23- 0.51- 0.76- 1.1- 1.6- 2.1- 3.1- 5.1- 7.1- 10.1- 13.1- (from) 0.50 0.75 1.00 1.5 2.0 3.0 5.0 7.0 10.0 13.0 18.0 > 18.0 Total N 0 0 3 24 30 78 162 68 30 0 0 0 395 NNE 0 1 41437115232300000433 NE 0 1 32748122128211000351 ENE 0 0 6 24 44 89 105 24 0 0 0 0 292 E 0 1 52237130162259000391 ESE 0 0 53359192246472000584 SE 0 0 6 21 62 379 409 120 13 0 1 0 1011 SSE 0 0 3 13 34 403 663 228 37 0 0 0 1381 S 0 0 2 6 20 172 567 93 9 0 0 0 869 SSW 0 1 0 4 8 98 249 27 0 0 0 0 387 SW 0 0 2 2 2 24 107 18 1 0 0 0 156 WSW 1 0 17916375100077 W 0 0 38831150000065 WNW 0 0 2 9 19 21 12 3 2 0 0 0 68 NW 0 0 115183950224 0 0 0149 NNW 0 1 3 18 31 48 119 43 9 1 0 0 273
Totals 1 5 49 247 466 1957 3263 774 118 1 1 0 6882
Number of Calm Hours for this Table 0 Number of Variable Direction Hours for this Table 0 Number of Invalid Hours 879 Number of Valid Hours for this Table 6882 Total Hours for the Period 26304
Note: Stability class based on the vertical temperature difference (ΔT or lapse rate) between the 60-meter and 10-meter measurement levels.
2.3S-78 Meteorology Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.3S-10 Joint Frequency Distribution of Wind Speed and Wind Direction (10-Meter Level) by Atmospheric Stability Class for the STP 3 & 4 Site (1997, 1999, and 2000) (Continued)
Hours at Each Wind Speed and Direction
Period of Record: 1997, 1999, 2000 Total Period
Elevation: Speed: PT SPD10 Direction: PT DIR10 Lapse:PT DT60-10
Stability Class:FΔT Moderately Stable
Wind Speed (m/s) Wind Direction 0.23- 0.51- 0.76- 1.1- 1.6- 2.1- 3.1- 5.1- 7.1- 10.1- 13.1- (from) 0.50 0.75 1.00 1.5 2.0 3.0 5.0 7.0 10.0 13.0 18.0 > 18.0 Total N 0 1 62829544120000161 NNE 0 2 14 43 49 67 52 0 0 0 0 0 227 NE 0 3 16 59 83 80 29 0 0 0 0 0 270 ENE 0 3 95861831601000231 E 0 0 87169982800000274 ESE 0 0 5911091192011000346 SE 0 1 3451532052800000435 SSE 0 0 017411673213000261 S 0 0 0 5 15 26 36 2 0 0 0 0 84 SSW 0 0 0446120000026 SW 0 0 0046110000021 WSW 0 0 013582000019 W 0 1 14171740000044 WNW 0 3 822291741000084 NW 0 0 72438321300000114 NNW 0 0 22328401610000110
Totals 0 14 79 495 732 1022 350 10 5 0 0 0 2707
Number of Calm Hours for this Table 0 Number of Variable Direction Hours for this Table 0 Number of Invalid Hours 879 Number of Valid Hours for this Table 2707 Total Hours for the Period 26304
Note: Stability class based on the vertical temperature difference (ΔT or lapse rate) between the 60-meter and 10-meter measurement levels.
Meteorology 2.3S-79 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.3S-10 Joint Frequency Distribution of Wind Speed and Wind Direction (10-Meter Level) by Atmospheric Stability Class for the STP 3 & 4 Site (1997, 1999, and 2000) (Continued)
Hours at Each Wind Speed and Direction
Period of Record: 1997, 1999, 2000 Total Period
Elevation: Speed: PT SPD10 Direction: PT DIR10 Lapse:PT DT60-10
Stability Class:GΔT Extremely Stable
Wind Speed (m/s) Wind Direction 0.23- 0.51- 0.76- 1.1- 1.6- 2.1- 3.1- 5.1- 7.1- 10.1- 13.1- (from) 0.50 0.75 1.00 1.5 2.0 3.0 5.0 7.0 10.0 13.0 18.0 > 18.0 Total N 1 3 18 50 41 46 15 0 0 0 0 0 174 NNE 0 2 12 85 125 69 27 0 0 0 0 0 320 NE 1 5 15 108 120 102 18 0 0 0 0 0 369 ENE 1 21910011252300000289 E 0 6 10 73 89 65 13 0 0 0 0 0 256 ESE 0 4 9578168510000225 SE 1 2 5266647000000147 SSE 0 1 36122620000050 S 0 1 331500000013 SSW 0 0 1203000000 6 SW 0 3 2010000000 6 WSW 1 0 1100300000 6 W 0 4 3861930000043 WNW 0 6 9292928000000101 NW 0 21022352540000098 NNW 0 313332928800000114
Totals 5 44 133 603 747 583 101 1 0 0 0 0 2217
Number of Calm Hours for this Table 0 Number of Variable Direction Hours for this Table 0 Number of Invalid Hours 879 Number of Valid Hours for this Table 2217 Total Hours for the Period 26304
Note: Stability class based on the vertical temperature difference (ΔT or lapse rate) between the 60-meter and 10-meter measurement levels.
2.3S-80 Meteorology Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.3S-10 Joint Frequency Distribution of Wind Speed and Wind Direction (10-Meter Level) by Atmospheric Stability Class for the STP 3 & 4 Site (1997, 1999, and 2000) (Continued)
Hours at Each Wind Speed and Direction
Period of Record: 1997, 1999, 2000 Total Period
Elevation: Speed: PT SPD10 Direction: PT DIR10 Lapse:PT DT60-10
Summary of All Stability Classes ΔT
Wind Speed (m/s) Wind Direction 0.23- 0.51- 0.76- 1.1- 1.6- 2.1- 3.1- 5.1- 7.1- 10.1- 13.1- (from) 0.50 0.75 1.00 1.5 2.0 3.0 5.0 7.0 10.0 13.0 18.0 > 18.0 Total N 1 4 29 115 132 276 553 438 236 10 0 0 1794 NNE 0 5 31 153 237 358 712 236 58 0 0 0 1790 NE 1 9 35 208 277 418 483 138 18 0 0 0 1587 ENE 1 5 34 201 236 312 386 160 42 0 0 0 1377 E 0 7 24 175 216 372 423 250 129 7 0 0 1603 ESE 0 4 19 191 274 442 572 400 233 10 0 0 2145 SE 1 3 14 102 304 729 1076 937 300 10 3 0 3479 SSE 0 1 6 41 105 698 1401 1003 280 10 0 0 3545 S 0 1 5 18 58 346 1668 1012 131 3 0 0 3242 SSW 0 1 1 10 24 219 678 265 47 0 0 0 1245 SW 0 3 4 5 18 92 277 100 24 0 0 0 523 WSW 2 0 310245495247 0 0 0219 W 0 5 7 24 48 110 62 10 6 1 0 0 273 WNW 0 9 2074991478436100 0 0479 NW 0 2 20 76 121 166 173 130 79 2 0 0 769 NNW 0 4 19 90 109 206 395 318 193 21 0 0 1355
Totals 6 63 271 1493 2282 4945 9038 5457 1793 74 3 0 25425
Number of Calm Hours for this Table 0 Number of Variable Direction Hours for this Table 0 Number of Invalid Hours 879 Number of Valid Hours for this Table 25425 Total Hours for the Period 26304
Note: Stability class based on the vertical temperature difference (ΔT or lapse rate) between the 60-meter and 10-meter measurement levels.
Meteorology 2.3S-81 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.3S-11 Joint Frequency Distribution of Wind Speed and Wind Direction (60-Meter Level) by Atmospheric Stability Class for the STP 3 & 4 Site (1997, 1999, and 2000)
Hours at Each Wind Speed and Direction
Period of Record: 1997, 1999, 2000 Total Period
Elevation: Speed: PT SPD10 Direction: PT DIR10 Lapse:PT DT60-10
Stability Class:AΔΤ Extremely Unstable
Wind Speed (m/s) Wind Direction 0.23- 0.51- 0.76- 1.1- 1.6- 2.1- 3.1- 5.1- 7.1- 10.1- 13.1- (from) 0.50 0.75 1.00 1.5 2.0 3.0 5.0 7.0 10.0 13.0 18.0 > 18.0 Total N 0 0 0 0 1102638244 0 0103 NNE 0 0 0 2 3 8 31 38 19 0 0 0 101 NE 0 0 0 0 31049329 0 0 0103 ENE 0 0 0 1 11029153 0 0 0 59 E 0 0 0 0 1 8 22 19 12 0 0 0 62 ESE 0 0 0 0 3 3 21 42 48 8 0 0 125 SE 0 0 001461173702100330 SSE 0 0 0 0 0 4 57 146 152 42 0 0 401 S 0 0 0 0 1 15 160 547 363 53 7 0 1146 SSW 0 0 0 0 1 24 115 125 114 37 0 0 416 SW 0 0 0 0 2155539225 0 0138 WSW 0 0 0 0 2 3 14 10 2 1 0 0 32 W 0 0 0029178520043 WNW 0 0 0 0 42223153 0 0 0 67 NW 0 0 0 2 4 8 27 23 19 6 0 0 89 NNW 0 0 0 2 116393442191 0154
Totals 0 0 0 7 30 169 746 1304 907 198 8 0 3369
Number of Calm Hours for this Table 0 Number of Variable Direction Hours for this Table 0 Number of Invalid Hours 1975 Number of Valid Hours for this Table 3369 Total Hours for the Period 26304
Note: Stability class based on the vertical temperature difference (ΔΤ or lapse rate) between the 60-m and 10-m measurement levels.
2.3S-82 Meteorology Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.3S-11 Joint Frequency Distribution of Wind Speed and Wind Direction (60-Meter Level) by Atmospheric Stability Class for the STP 3 & 4 Site (1997, 1999, and 2000) (Continued)
Hours at Each Wind Speed and Direction
Period of Record: 1997, 1999, 2000 Total Period
Elevation: Speed: PT SPD10 Direction: PT DIR10 Lapse:PT DT60-10
Stability Class:BΔΤ Moderately Unstable
Wind Speed (m/s) Wind Direction 0.23- 0.51- 0.76- 1.1- 1.6- 2.1- 3.1- 5.1- 7.1- 10.1- 13.1- (from) 0.50 0.75 1.00 1.5 2.0 3.0 5.0 7.0 10.0 13.0 18.0 > 18.0 Total N 01 01251671510048 NNE 0 0 0 0 01116207 0 0 0 54 NE 0 0 0 0 1 8 22 19 4 0 0 0 54 ENE 0 0 0 2 1 7 13 10 5 0 0 0 38 E 0 0 0 1 1 5 14 14 4 1 0 0 40 ESE 0 0 0 0 1 8 15 41 35 5 1 0 106 SE 0 0 0 0 1 6 42 92 67 11 0 0 219 SSE 0 0 0 0 1134397679 1 0231 S 0 0 0 0 111579460191 0243 SSW 0 0 0 0 0162616163 0 0 77 SW 0 0 0023154700031 WSW 0 0 002395000019 W 0 0 010650211016 WNW 0 0 0021161300023 NW 0 0 0 2 2 7 10 12 6 3 0 0 42 NNW 0 0 0 0 2 4 10 18 17 11 1 0 63
Totals 0 1 0 7 19 124 319 450 315 64 5 0 1304
Number of Calm Hours for this Table 0 Number of Variable Direction Hours for this Table 0 Number of Invalid Hours 1975 Number of Valid Hours for this Table 1304 Total Hours for the Period 26304
Note: Stability class based on the vertical temperature difference (ΔΤ or lapse rate) between the 60-meter and 10-meter measurement levels.
Meteorology 2.3S-83 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.3S-11 Joint Frequency Distribution of Wind Speed and Wind Direction (60-Meter Level) by Atmospheric Stability Class for the STP 3 & 4 Site (1997, 1999, and 2000) (Continued)
Hours at Each Wind Speed and Direction
Period of Record: 1997, 1999, 2000 Total Period
Elevation: Speed: PT SPD10 Direction: PT DIR10 Lapse:PT DT60-10
Stability Class:CΔΤ Slightly Unstable
Wind Speed (m/s) Wind Direction 0.23- 0.51- 0.76- 1.1- 1.6- 2.1- 3.1- 5.1- 7.1- 10.1- 13.1- (from) 0.50 0.75 1.00 1.5 2.0 3.0 5.0 7.0 10.0 13.0 18.0 > 18.0 Total N 0 0 0 1 2 8 16 14 29 6 0 0 76 NNE 0 0 0 2 11137176 0 0 0 74 NE 0 0 0 1 0 6 30 21 6 0 0 0 64 ENE 0 0 0 4 21130169 1 0 0 73 E 0 0 0 1 2 8 18 21 21 4 0 0 75 ESE 0 0 0 0 3 6 13 34 53 14 1 0 124 SE 0 0 002338103752000241 SSE 0 0 0 0 2 7 35 92 87 9 2 0 234 S 0 0 0 0 0 8 36 56 42 6 1 0 149 SSW 0 0 0 0 1 8 25 17 13 4 0 0 68 SW 0 0 0026106600030 WSW 0 0 100352100012 W 0 0 003660000015 WNW 0 0 0041656200033 NW 0 0 0 2 6 3 10 10 5 2 2 0 40 NNW 0 0 0 0 2 5 20 17 25 18 1 0 88
Totals 0 0 1 11 32 115 334 432 380 84 7 0 1396
Number of Calm Hours for this Table 0 Number of Variable Direction Hours for this Table 0 Number of Invalid Hours 1975 Number of Valid Hours for this Table 1396 Total Hours for the Period 26304
Note: Stability class based on the vertical temperature difference (ΔΤ or lapse rate) between the 60-meter and 10-meter measurement levels.
2.3S-84 Meteorology Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.3S-11 Joint Frequency Distribution of Wind Speed and Wind Direction (60-Meter Level) by Atmospheric Stability Class for the STP 3 & 4 Site (1997, 1999, and 2000) (Continued)
Hours at Each Wind Speed and Direction
Period of Record: 1997, 1999, 2000 Total Period
Elevation: Speed: PT SPD10 Direction: PT DIR10 Lapse:PT DT60-10
Stability Class:DΔΤ Neutral
Wind Speed (m/s) Wind Direction 0.23- 0.51- 0.76- 1.1- 1.6- 2.1- 3.1- 5.1- 7.1- 10.1- 13.1- (from) 0.50 0.75 1.00 1.5 2.0 3.0 5.0 7.0 10.0 13.0 18.0 > 18.0 Total N 0 0 0 4 8 23 138 224 347 73 7 0 824 NNE 0 0 0 0 12 28 155 176 157 10 0 0 538 NE 0 0 0 4 530117139545 0 0354 ENE 0 0 0 9 632771401057 0 0376 E 0 0 0 4 51581151171160 0443 ESE 0 0 0 1 63690234217422 0628 SE 0 0 0 3 4 30 153 352 383 40 6 0 971 SSE 0 0 0 2 8 24 139 340 431 78 10 0 1032 S 0 0 0 1 31491244233325 0623 SSW 0 0 0 1 211448979111 0238 SW 0 0 0 1 1 2 21 35 23 1 1 0 85 WSW 0 0 0 0 4 5 17 13 4 0 0 0 43 W 0 0 0 2 3 8 16 12 7 1 0 0 49 WNW 0 0 1 4 11 16 29 6 4 0 0 0 71 NW 0 0 1 3 7284448609 1 0201 NNW 0 0 0 5 9296615417276120523
Totals 0 0 2 44 94 331 1278 2357 2447 401 45 0 6999
Number of Calm Hours for this Table 0 Number of Variable Direction Hours for this Table 0 Number of Invalid Hours 1975 Number of Valid Hours for this Table 6999 Total Hours for the Period 26304
Note: Stability class based on the vertical temperature difference (ΔΤ or lapse rate) between the 60-meter and 10-meter measurement levels.
Meteorology 2.3S-85 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.3S-11 Joint Frequency Distribution of Wind Speed and Wind Direction (60-Meter Level) by Atmospheric Stability Class for the STP 3 & 4 Site (1997, 1999, and 2000) (Continued)
Hours at Each Wind Speed and Direction
Period of Record: 1997, 1999, 2000 Total Period
Elevation: Speed: PT SPD10 Direction: PT DIR10 Lapse:PT DT60-10
Stability Class:EΔΤ Slightly Stable
Wind Speed (m/s) Wind Direction 0.23- 0.51- 0.76- 1.1- 1.6- 2.1- 3.1- 5.1- 7.1- 10.1- 13.1- (from) 0.50 0.75 1.00 1.5 2.0 3.0 5.0 7.0 10.0 13.0 18.0 > 18.0 Total N 0 0 0 0 31568179108150 0388 NNE 0 0 0 3 61571168890 0 0352 NE 0 0 1 1 71490130561 0 0300 ENE 0 0 1 3 22789132291 0 0284 E 0 0 0 0 11 24 110 173 34 2 0 0 354 ESE 0 0 0 1 519149231530 0 0458 SE 0 0 0 3 4 272943811325 0 0 846 SSE 0 0 0 2 9 24 326 764 336 28 2 1 1492 S 0 0 0 0 4 14 212 414 295 17 2 0 958 SSW 0 0 0 2 3 6 116 240 102 5 0 0 474 SW 0 0 0 2 3 6 49 80 32 1 0 0 173 WSW 0 0 0 2 3 3 31 19 6 0 0 0 64 W 0 0 0209137901041 WNW 0 0 02517284300059 NW 0 0 0 2 4124143150 0 0117 NNW 0 0 0 3 213496974151 0226
Totals 0 0 2 28 71 245 1736 3034 1373 90 6 1 6586
Number of Calm Hours for this Table 0 Number of Variable Direction Hours for this Table 0 Number of Invalid Hours 1975 Number of Valid Hours for this Table 6586 Total Hours for the Period 26304
Note: Stability class based on the vertical temperature difference (ΔΤ or lapse rate) between the 60-meter and 10-meter measurement levels.
2.3S-86 Meteorology Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.3S-11 Joint Frequency Distribution of Wind Speed and Wind Direction (60-Meter Level) by Atmospheric Stability Class for the STP 3 & 4 Site (1997, 1999, and 2000) (Continued)
Hours at Each Wind Speed and Direction
Period of Record: 1997, 1999, 2000 Total Period
Elevation: Speed: PT SPD10 Direction: PT DIR10 Lapse:PT DT60-10
Stability Class:FΔΤ Moderately Stable
Wind Speed (m/s) Wind Direction 0.23- 0.51- 0.76- 1.1- 1.6- 2.1- 3.1- 5.1- 7.1- 10.1- 13.1- (from) 0.50 0.75 1.00 1.5 2.0 3.0 5.0 7.0 10.0 13.0 18.0 > 18.0 Total N 0 0 1 1 2113760221 0 0135 NNE 0 0 0 4 4153552360 0 0146 NE 0 0 1 2 6113731370 0 0125 ENE 0 0 0 2 71261326 1 0 0121 E 0 0 1 4 91677108120 0 0227 ESE 0 0 1 4 8 17 101 70 9 0 0 0 210 SE 0 0 036261581323000328 SSE 0 0 0 2 731271224102 0 0547 S 0 0 1 0 4 20 183 63 34 0 0 0 305 SSW 0 0 0 1 41234148 0 0 0 73 SW 0 0 0403308500050 WSW 0 0 14010139400041 W 0 0 0 3 21015102 0 0 0 42 WNW 0 0 25324313100069 NW 0 0 0 3 3 8 36 19 6 0 0 0 75 NNW 0 0 0 2 2 9 18 29 12 1 0 0 73
Totals 0 0 8 44 67 235 1137 864 207 5 0 0 2567
Number of Calm Hours for this Table 0 Number of Variable Direction Hours for this Table 0 Number of Invalid Hours 1975 Number of Valid Hours for this Table 2567 Total Hours for the Period 26304
Note: Stability class based on the vertical temperature difference (ΔΤ or lapse rate) between the 60-meter and 10-meter measurement levels.
Meteorology 2.3S-87 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.3S-11 Joint Frequency Distribution of Wind Speed and Wind Direction (60-Meter Level) by Atmospheric Stability Class for the STP 3 & 4 Site (1997, 1999, and 2000) (Continued)
Hours at Each Wind Speed and Direction
Period of Record: 1997, 1999, 2000 Total Period
Elevation: Speed: PT SPD10 Direction: PT DIR10 Lapse:PT DT60-10
Stability Class:GΔΤ Extremely Stable
Wind Speed (m/s) Wind Direction 0.23- 0.51- 0.76- 1.1- 1.6- 2.1- 3.1- 5.1- 7.1- 10.1- 13.1- (from) 0.50 0.75 1.00 1.5 2.0 3.0 5.0 7.0 10.0 13.0 18.0 > 18.0 Total N 0 0 2 0 2173127160 0 0 95 NNE 0 0 1 6 6163748231 0 0138 NE 0 1 1 1 3184347440 0 0158 ENE 0 1 4 7 7175351150 0 0155 E 0 2 1 5 8 21 101 62 12 0 0 0 212 ESE 0 0 0 10 9 27 92 86 14 0 0 0 238 SE 0 0 2 5 13 35 126 104 5 0 0 0 290 SSE 0 0 1 6 9 34 119 90 15 0 0 0 274 S 0 0 1 5 7 21 122 27 5 0 0 0 188 SSW 0 0 0257274000045 SW 0 0 2149193100039 WSW 0 0 1 3 3 8 11 13 1 0 0 0 40 W 0 0 1 1 7 9 10 10 2 3 0 0 43 WNW 0 0 04310273300050 NW 0 0 2 5 2 8 22 10 3 0 0 0 52 NNW 0 0 1 5 4162429120 0 0 91
Totals 0 4 20 66 92 273 864 614 171 4 0 0 2108
Number of Calm Hours for this Table 0 Number of Variable Direction Hours for this Table 0 Number of Invalid Hours 1975 Number of Valid Hours for this Table 2108 Total Hours for the Period 26304
Note: Stability class based on the vertical temperature difference (ΔΤ or lapse rate) between the 60-meter and 10-meter measurement levels.
2.3S-88 Meteorology Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.3S-11 Joint Frequency Distribution of Wind Speed and Wind Direction (60-Meter Level) by Atmospheric Stability Class for the STP 3 & 4 Site (1997, 1999, and 2000) (Continued)
Hours at Each Wind Speed and Direction
Period of Record: 1997, 1999, 2000 Total Period
Elevation: Speed: PT SPD10 Direction: PT DIR10 Lapse:PT DT60-10
Summary of All Stability Classes ΔΤ Wind Speed (m/s) Wind Direction 0.23- 0.51- 0.76- 1.1- 1.6- 2.1- 3.1- 5.1- 7.1- 10.1- 13.1- (from) 0.50 0.75 1.00 1.5 2.0 3.0 5.0 7.0 10.0 13.0 18.0 > 18.0 Total N 0 1 3 7 20 89 332 549 561 100 7 0 1669 NNE 0 0 1 17 32 104 382 519 337 11 0 0 1403 NE 0 1 3 9 25 97 388 419 210 6 0 0 1158 ENE 0 1 5 28 26 116 352 396 172 10 0 0 1106 E 0 2 2 15 37 97 423 548 266 23 0 0 1413 ESE 0 0 1 16 35 116 481 738 429 69 4 0 1889 SE 0 0 2 14 31 131 872 1337 735 97 6 0 3225 SSE 0 0 1 12 36 137 990 1753 1098 168 15 1 4211 S 0 0 2 6 20 103 861 1445 1032 127 16 0 3612 SSW 0 0 0 6 16 84 387 505 332 60 1 0 1391 SW 0 0 2 8 14 44 199 175 96 7 1 0 546 WSW 0 0 3 9 14 35 100 71 18 1 0 0 251 W 0 0 1 9 17 57 82 47 27 7 2 0 249 WNW 0 0 3153211614938190 0 0372 NW 0 0 3 19 28 74 190 165 114 20 3 0 616 NNW 0 0 1 17 22 92 226 350 354 140 16 0 1218
Totals 0 5 33 207 405 1492 6414 9055 5800 846 71 1 24329
Number of Calm Hours for this Table 0 Number of Variable Direction Hours for this Table 0 Number of Invalid Hours 1975 Number of Valid Hours for this Table 24329 Total Hours for the Period 26304
Note: Stability class based on the vertical temperature difference (ΔΤ or lapse rate) between the 60-meter and 10-meter measurement levels.
Meteorology 2.3S-89 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.3S-12 STP 3 & 4 System Meteorological Instrumentation Primary Tower Level Backup Tower Level Parameter (meters) (meters) Wind Speed 10, 60 10 Wind Direction 10, 60 10 Temperature 10, 60 10 Vertical Temperature (60–10) None Difference Sigma Theta None 10 Precipitation 0 (ground level) None Dew Point 3 None R. H./Temperature [1] 10, 60 Solar Radiometer 2.5 None
[1]Relative humidity/temperature instruments at 10-and 60 meters were added in December 2006 for dew point temperature calculations.
2.3S-90 Meteorology Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.3S-13 Meteorological Tower Siting Conformance Status Conformance RG 1.23 Criteria Status Remarks Tower Siting The meteorological tower sites and the Yes The site area is generally flat land proposed STP 3 & 4 location have similar meteorological exposure. The base of the tower is at approximately the Yes Tower elevation: 28' MSL same elevation as the finished plant grade of the proposed units. Finished plant grade: 34' MSL Location of the tower is not directly Yes Prevailing wind: SSE downwind of the existing and proposed plant cooling systems (i.e., MCR and the MCR – one mile S to SW of the mechanical cooling towers) under the meteorological towers [Note: It is prevailing downwind wind direction. expected that winds from the south to southwest would have an influence on observed meteorological data; however, the data collected from sensors will be representative of the plant site due to the size and location of the MCR.]
Two banks of mechanical draft cooling towers – 1.3 miles west of the meteorological towers Tower is not located on or near permanent Yes There are no large concrete or asphalt man-made surface. parking lot or temporary land disturbance, such as plowed fields or storage areas nearby.
Both the primary and backup towers are located on open fields with grassy surface underlying the towers.
Meteorology 2.3S-91 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.3S-14 Meteorological Instrument Siting Conformance Status Conformance RG 1.23 Criteria Status Remarks Sensor Siting Wind sensors are located at 10 obstruction Yes Both the primary and backup heights away from such obstructions meteorological towers are located in (including the existing and proposed unit open fields. The nearby trees and complex, trees, and nearby terrain) to brushes are ranging from 15 feet to 30 minimize any airflow modification (i.e., feet tall and mostly at 300 feet or more turbulent wake effects). from the towers. During routine maintenance, these trees are to be trimmed periodically to ensure that the 10-obstruction-height requirement is met. Wind sensors are located at heights that Yes Existing and STP 3 & 4 structures are avoid airflow modifications by nearby less than 250' in height and over a mile obstructions with heights exceeding one-half from the meteorological towers. of the wind measurement. Instrument shelter heights are less than 11 ft, which is less than half of the lower level sensor height at 10m (33'). Wind sensors are located to reduce airflow Yes Tower booms (8 feet long) are oriented modification and turbulence induced by the into the prevailing winds to reduce tower supporting structure itself. effects on the measurements. Air temperature and dew point sensors are Yes No ventilation systems or large parking located in such a way to avoid modification lots within 1000' of the tower. by the existing and proposed heat and moisture sources, such as ventilation The ground surface at the base of the systems, water bodies, or the influence of towers has been kept natural (i.e., large parking lots or other paved surfaces. grasses). It is expected that winds from the south to southwest would have an influence on observed meteorological data; however, the data collected from sensors will be representative of the plant site due to the size and location of the MCR.
Temperature sensors are mounted in downward pointing fan-aspirated radiation shields to minimize the adverse influences of thermal radiation and precipitation. Precipitation measured at ground level near Yes Precipitation gauge is equipped with the base of the tower. wind shields to minimize the wind- caused loss of precipitation.
2.3S-92 Meteorology Rev. 12
STP 3 & 4 Final Safety Analysis Report 2.5m (per (per ment 0.1°Cm 60 m, 10 1 W/m 0.01°C m 10 – m 60 0.1 m/s0.1 m 60 m, 10 0.25 mm base Tower Measure- 3.11-2005, 3.11-2005, ANSI/ANS- Resolution Ref. 2.3S-37) Elevation – azimuth 0.1° m 60 m, 10 mph ment 0.01°F 0.01 in Measure- Resolution Ref 2.3S-28) (per RG 1.23, 1° ment 0.01 in0.01 or mm 0.25 0.1°F [5]0.1°F 0.1% Measure- 0.085 mph0.085 0.1 or m/s 0.1 < 1 degree 1 < degree 1.0 azimuth 1.0° m 60 m, 10 Resolution – – 0.001 Langley – – – (1 mph) (1 mph) Starting Starting 2.3S-28) < 0.45 m/s < 0.45 Threshold (RG 1.23, Ref Ref 1.23, (RG – – – N/A 0.6 mph0.6 m/s 0.45 < Starting Starting (0.7mph) 0.3m/sec 0.3m/sec Threshold – (per Ref. mm/h 1.5°C 0.5°C0.1°C –1.5°C – – – Infinitesimal – 0.1°C or 0.1°F – 0.1°C Infinitesimal 0.01°C or 0.1°F 10 m 0.1°F or 0.1°C 0.1°C[2] m 3 volume volume azimuth System System 2.3S-37) observed Accuracy 3.11-2005, 3.11-2005, a rate < 50 50 < rate a ±10% for a a for ±10% 2.54 mm of of mm 2.54 wind speed ANSI/ANS- of observed equivalent to 0.2 m/s or 5% 5% or m/s 0.2 precipitation at – Ref. in) of 5% of speed volume volume System System (±2.7°F) (±0.9°F) (±2.7°F) 2.3S-28) (±0.18°F) 54 mm (0.1 Accuracy a rate <50 ±4%/±1.5°C ±4%/±1.5°C equivalent to Primary Tower Instruments Primary Tower 2. (per RG 1.23, 1.23, RG (per observed wind precipitation at in/h) (<2 mm/h (±0.45 mph) or or mph) (±0.45 N/A ±0.56°F ±0.5°C ±0.56°F ±1.5°C ±(1.0+0.01 x ±(1.5+0.02 x reading)%RH reading)%RH (14°F to 104°F): 104°F): to (14°F (-40°F to 356°F): At -10°C+40°C to At -40°C to +180°C to +180°C -40°C At ±0.008 Langley/min [4] Langley/min ±0.008 – 5% or W/m 10 RH N/A 0–2 0–2 (-4°F to (-4°F +120°C 0°–360° ±0.4°0°–360° degrees ±5° 5 +248°F) +122°F) -20°C to (-22°F to 0 – 6 in/hr 6 0 – ±1% a for ±10% 0% to 100% 0% to 100% Langley/min 0 – 100 mph100 – 0 mph ±0.1 m/s ±0.2 -30°C to -30°C +50°C Table 2.3S-15 Meteorological System – Preoperational Configuration – Preoperational System Meteorological 2.3S-15 Table N/A Vaisala / Vaisala Model 095 Model 6354 Model 53.2 or 53.4 or 53.2 Model 375B HUMICAP 180L2 Model 1565D, With With 1565D, Model Model 1564D, Model Model 1564D, Model HMT337 with Vaisala Vaisala with HMT337 Met One Instruments / Instruments One Met / Instruments One Met Met One Instruments / Instruments One Met Quick two Vane, Model Model Quick two Vane, 170-41 or Model 170-43 Model or 170-41 Models T-200, T-200UC Models T-200, N/A N/A N/A ±0.08°F ±0.1°C Device Copper Copper Sensors Platinum Capacitive Capacitive thermopile Chill Mirror constantan constantan Resistance Resistance Temperature Temperature (Optical) Dew and Temperature and Temperature Point Hygrometer Point Polymer Humidity Sensed Sensed Parameter Type Sensor Model Manufacturer/ Range Accuracy System Relative / Humidity [6] Temperature (for dew point temperature calculation) Wind DirectionWind Vane Wind Ambient / Instruments One Met Temperature Differential [1] Temperature Dew Point Lithium Chloride Precipitation [3] Bucket Tipping Met One Instruments / [5]Sigma-Theta N/A Wind SpeedWind Anemometer Cup / Instruments One Met Solar Radiometer
Meteorology 2.3S-93 Rev. 12
STP 3 & 4 Final Safety Analysis Report 0.1 m/s 0.1 ents at 60-ents bove grade. bove esolution as (per (per ment Measure- 3.11-2005, 3.11-2005, ANSI/ANS- Resolution Ref. 2.3S-37) Elevation mph ment Measure- Resolution Ref 2.3S-28) (per RG 1.23, ment Measure- 0.085 mph0.085 0.1 or m/s 0.1 < 1 degree 1 < degree 1.0 azimuth degree 1.0 Resolution e instrument is 2.56 meters a meters 2.56 is instrument e (1 mph) (1 mph) Starting Starting 2.3S-28) < 0.45 m/s < 0.45 Threshold (RG 1.23, Ref Ref 1.23, (RG 0.6 mph0.6 m/s 0.45 < Starting Starting (0.7mph) Threshold (per Ref. 0.5°C ------Infinitesimal 0.1°C or 0.1°F 0.1°C System System 2.3S-37) Accuracy 3.11-2005, 3.11-2005, wind speed ANSI/ANS- of observed 0.2 m/s or 5% 5% or m/s 0.2 above grade and the bottom th of bottom the and grade above Direction variation measurements, and therefore has the same r same the has therefore and measurements, variation Direction Ref. 5% of speed System System (±0.9°F) 2.3S-28) Accuracy d on arithmetic differences in the Ambient Temperature measurem Ambient Temperature in the differences arithmetic d on Backup Tower Instruments Tower Backup (per RG 1.23, 1.23, RG (per observed wind (±0.45 mph) or or mph) (±0.45 installed and placed in operation in December of 2006. December in in operation placed and installed ±0.56°F ±0.5°C (-4°F to (-4°F +120°C +248°F) -20°C to 0°– 360° ±0.4° ±5° 5°azimuth 0.3 m/sec 0–100 mph ±0.1 mph ±0.2 m/s each time an internal bucket fills with 0.01 inches of water. T-200UC 53.2 or 53.4 or 53.2 Models T-200, Models T-200, Table 2.3S-15 Meteorological System – Preoperational Configuration (Continued) Configuration – Preoperational System Meteorological 2.3S-15 Table Model 1565D, With With 1565D, Model Model 1564D, Model Model 1564D, Model Met One Instruments / Instruments One Met Quick two Vane, Model Model Quick two Vane, 170-41 or Model 170-43 Model or 170-41 Platinum Resistance meter and 10-meter locations. 10-meter and meter the Wind Direction measurements. Direction the Wind [2] meters is 2.77 instrument the Dew Point for arm attachment The [1] value is a calculated value base The Differential Temperature [3] is collected and drained Water [4] rack). equipment (Primary at of N0EM-XY-8134 As the output measured [5] the Wind on based value is a calculated value Sigma-Theta The [6] was instrument / Temperature Relative Humidity The Sensed Sensed Parameter Type Sensor Model Manufacturer/ Range Accuracy System Wind DirectionWind Vane Wind / Instruments One Met Ambient Temperature Sigma-Theta [5] N/A N/A N/A N/A ------N/A ----- 1° ----- 0.1 degrees azimuth Wind SpeedWind Anemometer Cup / Instruments One Met
2.3S-94 Meteorology Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.3S-16 STP 3 & 4 Data Collection and Recording Equipment Accuracy Equipment System Accuracy Microprocessor Primary and Backup Better than +0.10% of full scale Digital Data Recorder Primary Current: +0.10% of full scale Temperature Delta temperature Dew Point Solar radiation Precipitation Wind speed Wind direction Digital Data Recorder Backup Current: +0.10% of full scale Temperature Wind speed Wind direction Sigma theta Disk Drives Primary and Backup Various digital devices Source: Reference 2.3S-40, STPEGS Updated Safety Analysis Report, Revision 13
Meteorology 2.3S-95 Rev. 12
STP 3 & 4 Final Safety Analysis Report 10 m, 60 m, m 10 2.5 m 2.5 (per (per ment 2.3S-37) Elevation Measure- ANSI/ANS- Resolution 3.11-2005, Ref. Ref. 3.11-2005, 0.1° azimuth0.1° m 60 m, 10 0.1°C 0.25 mm base Tower 0.1 m/s0.1 m 60 m, 10 0.01°C 60 m – 10 m – ment Measure- Resolution Ref. 2.3S-28) (per RG 1.23, – 0.01 in 0.01 0.1 m/s or 0.1 0.1 or m/s 0.1 mph 0.01°F ment Measure- Resolution 1° 0.1°F [3]0.1°F 0.1% in0.01 or mm 0.25 Langley0.001 – 0.1 m/sec 0.1 (0.1 mph) 1° 1.0°azimuth ° 1.0 m 60 m, 10 Ref. Starting Starting 2.3S-28) (RG 1.23, (RG 1.23, Threshold – – – – (1 mph) (1 mph) (1 Starting Starting Threshold N/A – – – Virtually zeroVirtually 0.45 < m/s System 2.3S-37) Accuracy 3.11-2005, Ref. Ref. 3.11-2005, (per ANSI/ANS- – 10 W/m or 5% 5% or W/m 10 1.5°C a for ±10% equivalent volume of mm 2.54 to precipitation ata mm/h 50 < rate observed 0.2 m/s or 5% of 5% or m/s 0.2 observed wind speed Ref. System System 2.3S-28) Accuracy 7°F) (per1.23, RG PRIMARY TOWER INSTRUMENTS TOWER PRIMARY – volume equivalent equivalent volume (0.1 mm 2.54 to in) of precipitation at a rate <50 mm/h(< 2 in/h) ±0.2 m/s (±0.45 of 5% or mph) observed wind speed ±0.5°C (±0.9°F) 0.5°C – ±1.5°C / ±4% (±2. – 0.1°F 0.1°C or 0.1°F 0.1°C 10 m, 60 m ±10% for a a for ±10% N/A ±0.15 m/sec 5 m/sec or m/sec or m/sec 5 ±0.15 m/sec 5 ±2% mph 11.2 mph (±0.33 mph) ±2% or 11.2 [5] Langley/min +0.008 – ±0.5°C (±0.9°F) At -10°Cto +40°C (14°F x ±(1.0+0.01 104°F): to reading)%RH (- +180°C to -40°C At 40°F to 356°F): x ±(1.5+0.02 reading)%RH Table 2.3S-17 Meteorological System – Operational Configuration Operational – System Meteorological 2.3S-17 Table 0–6 in/hr0–6 ±1% 0–2 0–2 Langley/min 0 to 50 m/sec 50 0 to mph) 112 to (0 0° to 360°0° to ±3° degree ±5 azimuth degrees 5 zero Virtually m/s 0.45 < -20°C to to -20°C +120°C to (-4°F +248°F) 0% to 100% RH N/A Model Range Accuracy System Manufacturer/ / Model 375B / Model Met OneInstruments 095 / Model / Model 50.5 [1] 50.5 Model / / Model 50.5 [1] 50.5 Model / Met OneInstruments T-200, / Models T-200UC / Vaisala HMT337 with Vaisala 180L2 HUMICAP N/A Copper Copper constantan thermopile Platinum Platinum Resistance Temperature Device Capacitive Polymer and Humidity Temperature Sensors N/A N/A N/A N/A ±0.18°F (±0.18°F) ±0.1°C 0.1°C N/A – 0.01°F or 0.01°C Sensed Parameter Type Sensor Precipitation [4]Precipitation Bucket Tipping Instruments One Met Solar Solar Radiometer Wind Speed UltrasonicInstruments One Met Wind Direction UltrasonicAmbient Temperature Instruments One Met Relative / Humidity Temperature dew (for [2 point temperature calculation)] Sigma-Theta [6] Differential [2] Temperature 2.3S-96 Meteorology Rev. 12
STP 3 & 4 Final Safety Analysis Report (per (per esolution as esolution ment 2.3S-37) Elevation Measure- ANSI/ANS- Resolution 3.11-2005, Ref. Ref. 3.11-2005, 0.1 m/s0.1 m 10 ment Measure- Resolution Ref. 2.3S-28) (per RG 1.23, 0.1 m/s or 0.1 0.1 or m/s 0.1 mph ment Measure- Resolution 0.1 m/sec 0.1 (0.1 mph) m 1°azimuth 10 1.0° 1.0° Ref. Starting Starting 2.3S-28) (RG 1.23, (RG 1.23, Threshold (1 mph) (1 mph) (1 Starting Starting Threshold measurements, and thereforethe hassame r Virtually zeroVirtually 0.45 < m/s System 2.3S-37) Accuracy 3.11-2005, Ref. Ref. 3.11-2005, (per ANSI/ANS- 0.2 m/s or 5% of 5% or m/s 0.2 observed wind speed Ref. ents at60-ents measurem Temperature Ambient the in differences arithmetic on d System System 2.3S-28) Accuracy fills with 0.01 inches of water. (per1.23, RG BACKUP INSTRUMENTS TOWER ±0.2 m/s (±0.45 of 5% or mph) observed wind speed ±0.5°C (±0.9°F) 0.5°C – – 1°F 0.1°C or 0.1°F 0.1°C 10 m e based on Relative Humidity and Ambient Temperature and Ambient Humidity Relative on e based has an external electrical heater circuit heater electrical external an has lue based on the Wind Direction variation variation Wind Direction the on lue based ±0.15 m/sec 5 m/sec or m/sec or m/sec 5 ±0.15 m/sec 5 ±2% mph 11.2 mph (±0.33 mph) ±2% or 11.2 ±0.5°C (±0.9°F) EM-XY-8134 (Primary equipment rack). equipment (Primary EM-XY-8134 each time an internal bucket 0 to 50 m/sec 50 0 to mph) 112 to (0 0° to 360°0° to ±3° ±5°azimuth 5° zero] Virtually m/s 0.45 < -20°C to to -20°C +120°C to (-4°F +248°F) Table 2.3S-17 Meteorological System – Operational Configuration (Continued) Configuration Operational – System Meteorological 2.3S-17 Table Model Range Accuracy System Manufacturer/ / Model 50.5 [1] 50.5 Model / / Model 50.5 [1] 50.5 Model / Met OneInstruments T-200, / Models T-200UC Platinum Platinum Resistance Temperature Device N/A N/A N/A N/A – – N/A – 1° – azimuth 0.1° m 10 meter and 10-meter locations. 10-meter and meter the Wind Direction measurements. Direction Wind the [3] valu is a calculated value Dew The Point Temperature [5]N0 of output the at measured As [6] va is a calculated value Sigma-Theta The [2] The Differential Temperature value is a calculated value value base is a calculated value [2] Temperature Differential The [4] is collected and drained Water [1] The / sonicDirection Wind instrument Speed Sensed Parameter Type Sensor Wind Speed UltrasonicInstruments One Met Wind Direction UltrasonicAmbient Temperature Instruments One Met Sigma-Theta [6] Meteorology 2.3S-97 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.3S-18 Annual Data Recovery Rate (in percent) for STP 3 & 4 Meteorological Monitoring System (1997, 1999, and 2000) 3-Year Parameter 1997 1999 2000 Composite Wind Speed (10 m) 100.0 99.6 99.5 99.7 Wind Speed (60 m) 96.2 93.6 90.9 93.6 Wind Direction (10 m) 99.9 99.6 99.5 99.7 Wind Direction (60 m) 96.4 94.6 91.1 94.0 -Temperature (60 m–10 m) [1] 96.6 96.1 97.3 96.7 Ambient Temperature (10 m) 93.0 95.0 92.2 93.4 Ambient Temperature (60 m) 93.0 91.3 90.0 91.4 Composite Parameters WS/WD (10m), T (60m-10m) [1] 96.6 96.1 97.3 96.7 WS/WD (60m), T (60m-10m) [1] 95.3 91.6 90.6 92.5
[1] Temperature difference (ΔT) between 60-meter and 10-meter levels.
2.3S-98 Meteorology Rev. 12
STP 3 & 4 Final Safety Analysis Report [2] CURRENT ility Classes ility SAR [1] ORIGINAL [2] CURRENT [1] Stability Class GClass Stability Stab All ORIGINAL [2] CURRENT Stability Class F Class Stability [1] ORIGINAL [2] CURRENT Stability Class E Class Stability [1] ORIGINAL [2] ass D ass CURRENT Stability Cl Stability [1] ORIGINAL and 2000 (Tables 2.3S-10 to 2.3S-11). and 2000 (Tables [2] CURRENT 1, 1976 to September 30, 1977 (STP 1 (STP & 2 UF 1977 30, to September 1, 1976 October and to July 20, 1976 ly 21, 1973 Stability Class C Class Stability [1] ORIGINAL iled from 1997, 1999, iled [2] CURRENT Stability Class B Class Stability [1] ORIGINAL [2] CURRENT Stability Class A Class Stability [1] ORIGINAL Units 1 & 2 Tables 2.3-29 to 2.3-36, Reference 2.3S-40). Reference to 2.3-36, 2.3-29 1 & 2 Tables Units [1] Thewas compiled from Ju “ORIGINAL” data [2]comp was “CURRENT” The data E 0.15S 0.26 1.79 0.15 0.15 4.6 0.27 1.25 0.32 1.03 1.61 1.22 1.96 0.66 1.23 3.2 1.54 2.66 1.2 3.14 1.08 3.42 1.12 1.38 1.01 0.33 5.73 0.56 0.05 6.32 12.54 12.75 N 0.40.430.40.210.510.323.833.231.371.550.660.630.520.687.697.05 W 0.08 0.15 0.06 0.06 0.1 0.07 0.36 0.19 0.24 0.26 0.22 0.17 0.26 0.17 1.32 1.07 SE 0.97 1.33 0.71 0.93 1.08 1.07 4.78 4.1 3.59 3.98 1.81 1.71 0.58 0.58 13.52 13.70 NE0.260.430.270.20.370.292.161.421.381.381.241.061.691.457.376.23 Table 2.3S-19 Comparison of Onsite Data – Wind Direction Frequency Distribution by Stability Class (frequency in percent) (frequency Class by Stability Distribution Frequency Direction – Wind Data Comparison of Onsite 2.3S-19 Table SW0.30.670.230.140.180.160.470.370.420.610.330.080.360.022.292.05 NW 0.21 0.38 0.14 0.16 0.15 0.21 0.74 0.86 0.39 0.59 0.3 0.45 0.35 0.39 2.28 3.04 ESE 0.26SSE 1.36 0.49 0.28 1.6 0.42 1.11 0.38 0.9 0.47 1.03 2.06 0.9 2.51 4.54 1.53 3.89 2.3 4.81 1.28 5.43 1.36 1.87 0.66 1.03 0.88 0.48 6.45 0.2 8.43 15.20 13.95 ENE0.180.260.210.180.270.261.461.521.041.150.980.911.291.145.435.42 NNE 0.29 0.37 0.25 0.21 0.34 0.28 2.8 2.32 1.35 1.7 1.03 0.89 0.98 1.26 7.04 7.03 SSW 0.83 1.69 0.45 0.28 0.51 0.31 1.1 0.98 0.94 1.52 0.61 0.1 0.32 0.02 4.76 4.90 NNW0.290.610.30.260.320.362.462.161.131.070.640.430.460.455.605.34 WSW 0.11 0.16 0.09 0.09 0.08 0.04 0.3 0.17 0.21 0.3 0.14 0.07 0.18 0.02 1.11 0.85 WNW0.110.320.090.110.110.130.340.330.260.270.190.330.230.41.331.89
Meteorology 2.3S-99 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.3S-20 Comparison of Onsite Data – Stability Class Distribution (in percent) STABILITY CLASSES ABCDEFG ORIGINAL [1] 7.59 6.00 6.93 32.22 23.08 14.06 10.13 CURRENT [2] 13.73 5.31 5.85 28.67 27.07 10.65 8.72
[1] The “ORIGINAL” data was compiled from July 21, 1973 to July 20, 1976 and October 1, 1976 to September 30, 1977 (STP 1 & 2 UFSAR Tables 2.3-29 to 2.3-36, Reference 2.3S-40). [2] See Table 2.3S-9.
2.3S-100 Meteorology Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.3S-21 EAB and LPZ Distances Distance from Envelope Surrounding STP 3 & 4 Directional To EAB To EAB To LPZ To LPZ Sector (feet) (meters) (feet) (meters) N 2503 763 13304 4055 NNE 2572 784 13684 4171 NE 2815 858 14183 4323 ENE 3691 1125 14941 4554 E 5098 1554 15912 4850 ESE 6335 1931 16765 5110 SE 6611 2015 17287 5269 SSE 6106 1861 17241 5255 S 5650 1722 16486 5025 SSW 4911 1497 15545 4738 SW 3825 1166 14350 4374 WSW 3084 940 13701 4176 W 2746 837 13182 4018 WNW 2343 714 12874 3924 NW 2251 686 12831 3911 NNW 2464 751 13156 4010
Meteorology 2.3S-101 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.3S-22 [Not Used]
2.3S-102 Meteorology Rev. 12
STP 3 & 4 Final Safety Analysis Report /Q χ 1 13 13 5.4 2.4 0.8 0.3 0.9 7.5 3.6 0.9 0.1 0.2 0.7 32.3 32.3 43.7 43.7 18.6 18.6 131.4 131.4 0-2 HR Exceed in Sector in Sector Exceed HRS PER YR MAX YR HRS PER Annual Annual Average /Q Exceeded χ /Q Values) /Q Values) /Q) Values (Sec/Cubic Meter) Versus Averaging Time (Note: Site (Note: Time Averaging Versus Meter) (Sec/Cubic /Q) Values χ χ 7E-04 7.97E-05 5.20E-05 3.09E-05 8-24 8-24 Hours Days 1-4 4-30 Days Limit = 5% Limit 0-8 Hours /Q Values at the Dose Calculation EAB Site Exclusion Area Boundary Calculations - Calculations Boundary Area Exclusion EAB Site Calculation at the Dose /Q Values χ 0-2 0-2 Hours 1.62E-04 1.23E-04 1.0 2.74E-04 hr 0-2 Entire Site Max Hours Total 714 2.74E-04 1.85E-04 1.52E-04 9.95E-05 5.40E-05 2.56E-05 686 2.49E-04 1.76E-04 1.49E-04 1.02E-04 5.96E-05 3.09E-05 837 2.25E-04 1.47E-04 1.19E-04 7.50E-05 3.87E-05 1.72E-05 763 1.22E-04 8.24E-05 6.77E-05 4.42E-05 2.39E-05 1.13E-05 784 9.92E-05 5.97E-05 4.63E-05 2.67E-05 1.21E-05 4.58E-06 751 1.74E-04 1.22E-04 1.02E-04 6.93E-05 3.97E-05 2.01E-05 940 2.03E-04 1.31E-04 1.05E-04 6.54E-05 3.31E-05 1.43E-05 858 6.87E-05 3.81E-05 2.84E-05 1.50E-05 5.98E-06 1.95E-06 1125 2.42E-05 1.38E-05 1.04E-05 5.68E-06 2.37E-06 8.14E-07 1166 1.71E-04 1.09E-04 8.72E-05 5.36E-05 2.66E-05 1.13E-05 1722 9.63E-05 5.37E-05 4.01E-05 2.12E-05 8.54E-06 2.80E-06 1554 3.28E-05 1.78E-05 1.32E-05 6.81E-06 2.64E-06 8.29E-07 2015 6.17E-05 3.14E-05 2.24E-05 1.08E-05 3.78E-06 1.05E-06 1931 6.52E-05 3.29E-05 2.33E-05 1.11E-05 3.80E-06 1.03E-06 1861 7.12E-05 3.81E-05 2.79E-05 1.42E-05 5.35E-06 1.63E-06 (Meters) Distance /Q χ
S E N W SE NE SW NW ESE SSE ENE NNE SSW 1497 1.21E-04 7.26E-05 5.62E-05 3.23E-05 1.46E-05 5.49E-06 NNW WSW WNW Sector Table 2.3S-23 PAVAN Results - 0.5% - Results 2.3S-23 PAVAN Table Downwind Site Limit Site Max 0-2 hr Max 0-2 Building Wake Credit Is Not Included. Relative Concentration ( Relative Concentration Credit Is Not Included. Building Wake
Meteorology 2.3S-103 Rev. 12
STP 3 & 4 Final Safety Analysis Report /Q χ 1.1 6.7 2.7 3.4 1.5 5.3 7.9 16.5 16.5 22.2 22.2 40.4 43.7 34.8 31.5 31.5 24.3 10.4 10.4 10.3 10.3 262.6 262.6 0-2 HR /Q Values) Exceed in Sector in Sector Exceed χ HRS PER YR MAX Annual Average /Q Exceeded χ 6.06E-067.40E-06 1.82E-06 2.30E-06 4.17E-07 5.49E-07 1.40E-06 4.51E-07 1.12E-07 7.48E-06 2.59E-06 7.09E-07 4.97E-06 1.78E-06 5.08E-07 8.18E-07 2.38E-07 5.26E-08 2.67E-06 6.80E-07 1.27E-07 3.00E-06 8.24E-07 1.70E-07 /Q Values at the Dose Calculation LPZ the Dose Calculation at Values /Q χ 8-24 Hours 1-4 Days 4-30 Days 0-8 Hours /Q) Values (Sec/Cubic Meter) Versus Averaging Time (Note: Site Limit = 5% (Note: Site Limit Time Averaging Meter) Versus (Sec/Cubic Values /Q) χ 0-2 Hours 3.99E-05 2.05E-05 1.47E-05 7.12E-06 2.52E-06 7.09E-07 5.27E-05 Hours Entire Site Max 0-2 hr Total Low Population Zone Calculations - Building Wake Credit Is Not Included. Credit Wake Building - Calculations Zone Low Population Table 2.3S-24 PAVAN Results - 0.5% - 0.5% Results PAVAN 2.3S-24 Table 3911 4.34E-05 2.20E-05 1.56E-05 5110 2.59E-05 1.08E-05 6.94E-06 4374 5.16E-05 2.44E-05 1.67E-05 4323 6.35E-06 2.87E-06 1.93E-06 5025 3.58E-05 1.59E-05 1.06E-05 4.40E-06 1.24E-06 2.65E-07 4018 4.93E-05 2.34E-05 1.61E-05 7.18E-06 2.25E-06 5.43E-07 4055 1.34E-05 7.06E-06 5.13E-06 2.56E-06 9.47E-07 2.80E-07 5269 2.36E-05 1.00E-05 6.54E-06 2.58E-06 6.81E-07 1.33E-07 4850 8.14E-06 3.67E-06 2.46E-06 1.04E-06 3.00E-07 6.58E-08 5255 2.55E-05 1.11E-05 7.36E-06 Distance (Meters) /Q χ Relative Concentration ( Concentration Relative S E N W SE NE SW NW ESE SSE ENE 4554 3.08E-06 1.45E-06 9.95E-07 4.40E-07 1.36E-07 3.25E-08 NNE 4171 9.22E-06 4.45E-06 3.09E-06 SSW 4738 4.47E-05 2.06E-05 1.40E-05 NNW 4010 2.72E-05 1.41E-05 1.01E-05 WSW 4176 5.27E-05 2.45E-05 1.67E-05 7.30E-06 2.22E-06 5.15E-07 WNW 3924 4.81E-05 2.35E-05 1.65E-05 7.57E-06 2.48E-06 6.34E-07 Sector Downwind Downwind Site Limit Max 0-2 hr
2.3S-104 Meteorology Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.3S-25 ARCON96 χ/Q Values (sec/m3) ARCON96 χ/Q Values at the Control Room Air Intake “C” Release Point 0 – 2 hours 2 – 8 hours 8 – 24 hours 1 – 4 days 4 – 30 days Reactor Building 9.14E-04 4.98E-04 2.22E-04 1.68E-04 1.16E-04 Plant Stack DCD Control Room 3.10E-03[1] NA 1.83 E-03 1.16 E-03 5.12 E-04 Limit Turbine Building 3.38E-04 2.43E-04 1.16E-04 6.28E-05 5.43E-05 Truck Doors DCD Turbine 5.17E-04 NA 3.05E-04 1.93E-04 8.53E-05 Building Limit [2] ARCON96 χ/Q Values at the Control Room Air Intake “B” Release Point 0 – 2 hours 2 – 8 hours 8 – 24 hours 1 – 4 days 4 – 30 days Reactor Building 2.03E-03 1.68E-03 5.88E-04 6.29E-04 5.59E-04 Plant Stack DCD Control Room 3.10E-03 [1] NA 1.83 E-03 1.16 E-03 5.12 E-04 Limit Turbine Building 5.20E-04 4.18E-04 1.84E-04 1.18E-04 9.15E-05 Truck Doors DCD Turbine 5.17E-04 [3] NA 3.05E-04 1.93E-04 8.53E-05 Building Limit [2] ARCON96 χ/Q Values at the Technical Support Center Air Intake Release Point 0 – 2 hours 2 – 8 hours 8 – 24 hours 1 – 4 days 4 – 30 days Reactor Building 5.89E-04 4.50E-04 1.91E-04 1.27E-04 9.39E-05 Plant Stack DCD Control Room 3.10E-03[1] NA 1.83 E-03 1.16 E-03 5.12 E-04 Limit Turbine Building 3.28E-04 2.26E-04 1.06E-04 5.67E-05 4.99E-05 Truck Doors DCD Turbine 5.17E-04 NA 3.05E-04 1.93E-04 8.53E-05 Building Limit [2]
NA -Not available
[1] reference ABWR DCD specifies that this value is for 0-8 hour.
Meteorology 2.3S-105 Rev. 12
STP 3 & 4 Final Safety Analysis Report
[2] reference ABWR DCD specifies that the χ/Q values for Turbine Building release are a factor 6 less than those from the Reactor Building release. [3] The value provided in the 0-2 hour column for the DCD Turbine Building Limit is the 0-8 hour DCD Turbine Building Limit. The equivalent calculated ARCON96 0-8 hr value is estimated to be 4.44E-04 sec/m3 based on the method provided in Section 3.7 of NUREG/CR-6331, which does not exceed the 0-8 hour DCD Turbine Building Limit (5.17E-04 sec/m3).
2.3S-106 Meteorology Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.3S-26 Distances from the Release Points to Sensitive Receptors Distance to Nearest Distance to Nearest Residence, Vegetable Residence, Vegetable Garden, and Meat Animal Garden, and Meat Animal Closest of (meters) from (meters) from two (meters) Center of Direction STP 1 & 2 STP 3 STP 4 STP 3 or 4 N 5600 5157 5193 5157 NNE 8000 7802 7932 7802 NE 8000 8083 8295 8083 ENE 7200 7549 7811 7549 E 8000 8557 8831 8557 ESE 5600 6287 6538 6287 SE 5600 6319 6517 6319 SSE 8000 8650 8768 8650 S0 000 SSW 8000 8256 8177 8177 SW 7200 7185 7015 7015 WSW 4000 3734 3506 3506 W 7200 6673 6399 6399 WNW 7200 6521 6264 6264 NW 7200 6482 6292 6292 NNW 5600 4966 4884 4884
Note: For STP 1 & 2, if the distance is greater than 8,000 meters, then the distance is taken as 8,000 meters. If a pathway is not applicable, the receptor distance is 0 meters
Meteorology 2.3S-107 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.3S-26a Distances from Table 2.3S-26b Distances from Release Points to the EAB Release Points to the Site Boundary Direction From Distance (m) Direction From Distance (m) S Unit 4 1756 S Unit 3 6380 SSW Unit 4 1519 SSW Unit 4 4117 SW Unit 4 1271 SW Unit 4 2248 WSW Unit 4 1006 WSW Unit 4 1916 W Unit 4 934 W Unit 4 1917 WNW Unit 4 859 WNW Unit 4 1917 NW Unit 4 838 NW Unit 4 1295 NNW Unit 4 839 NNW Unit 4 1115 N Unit 4 874 N Unit 4 1098 NNE Unit 4 970 NNE Unit 3 1123 NE Unit 4 1155 NE Unit 3 1311 ENE Unit 3 1497 ENE Unit 3 1649 E Unit 3 1838 E Unit 3 2242 ESE Unit 3 2110 ESE Unit 3 2309 SE Unit 3 2151 SE Unit 3 6180 SSE Unit 4 1944 SSE Unit 3 6652
2.3S-108 Meteorology Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.3S-27 XOQDOQ-Predicted Maximum χ/Q and (D/Q) Values at Receptors of Interest Direction from Distance χ/Q Type of Location Site (miles) (sec/m3) No Decay EAB NW 0.52 1.50E-05 Site Boundary NNW 0.69 8.10E-06 Resident WSW 2.18 6.30E-07 Meat Animal WSW 2.18 6.30E-07 Vegetable Garden WSW 2.18 6.30E-07 Unit 4 Reactor WNW 0.17 8.30E-05
2.26 Day Decay EAB NW 0.52 1.50E-05 Site Boundary NNW 0.69 8.10E-06 Resident WSW 2.18 6.20E-07 Meat Animal WSW 2.18 6.20E-07 Vegetable Garden WSW 2.18 6.20E-07 Unit 4 Reactor WNW 0.17 8.30E-05
8 Day Decay EAB NW 0.52 1.40E-05 Site Boundary NNW 0.69 7.30E-06 Resident WSW 2.18 5.10E-07 Meat Animal WSW 2.18 5.10E-07 Vegetable Garden WSW 2.18 5.10E-07 Unit 4 Reactor WNW 0.17 8.00E-05
Direction from Distance D/Q Type of Location Site (miles) (1/m2) EAB NW/NNW 0.52 1.00E-07 Site Boundary NNW 0.69 6.40E-08 Resident NNW 3.03 1.80E-09 Meat Animal NNW 3.03 1.80E-09 Vegetable Garden NNW 3.03 1.80E-09 Unit 4 Reactor WNW 0.17 3.40E-07
Meteorology 2.3S-109 Rev. 12
STP 3 & 4 Final Safety Analysis Report 9E-07 4.722E-07 3.331E-07 2.502E-07 1.967E-07 1.600E-07 7E-07 3.658E-07 2.567E-07 1.921E-07 1.504E-07 1.220E-07 5E-07 2.709E-07 1.871E-07 1.382E-07 1.070E-07 8.590E-08 5E-07 8.360E-08 5.889E-08 4.421E-08 3.473E-08 2.823E-08 11E-07 5.015E-07 3.538E-07 2.659E-07 2.091E-07 1.701E-07 55E-07 5.577E-07 3.947E-07 2.974E-07 2.343E-07 1.909E-07 35E-07 2.570E-07 1.802E-07 1.347E-07 1.055E-07 8.545E-08 20E-07 1.753E-07 1.240E-07 9.346E-08 7.365E-08 6.001E-08 19E-07 6.091E-07 4.251E-07 3.167E-07 2.471E-07 1.996E-07 89E-08 5.656E-08 3.928E-08 2.915E-08 2.267E-08 1.827E-08 17E-07 1.995E-07 1.405E-07 1.054E-07 8.273E-08 6.719E-08 423E-07 4.780E-07 3.380E-07 2.546E-07 2.005E-07 1.633E-07 360E-07 5.341E-07 3.754E-07 2.812E-07 2.205E-07 1.789E-07 542E-07 4.735E-07 3.281E-07 2.430E-07 1.887E-07 1.517E-07 849E-07 1.156E-07 7.981E-08 5.893E-08 4.564E-08 3.664E-08 122E-08 3.861E-08 2.686E-08 1.995E-08 1.554E-08 1.253E-08 Boundaries /Q Values at the Standard Radial Distances and Distance-Segment and Distance-Segment Distances Radial at the Standard Values /Q χ DISTANCE IN MILES FROM THE SITE DISTANCE - NO INTERMITTENT RELEASES /Q at Various Distances Various /Q at χ Table 2.3S-28 XOQDOQ-Predicted Annual Averate Annual Averate 2.3S-28 XOQDOQ-Predicted Table S 3.024E-05 9.780E-06 5.079E-06 2.601E-06 1.052E-06 5.73 E 6.872E-06 2.178E-06 1.131E-06 5.827E-07 2.379E-07 1.30 N 2.412E-05 8.121E-06 4.263E-06 2.104E-06 8.172E-07 4.33 W 3.799E-05 1.208E-05 6.311E-06 3.266E-06 1.338E-06 7.35 SE 1.645E-05 5.201E-06 2.712E-06 1.396E-06 5.690E-07 3.1 NE 5.005E-06 1.648E-06 8.572E-07 4.271E-07 1.679E-07 8.9 SW 4.526E-05 1.411E-05 7.274E-06 3.787E-06 1.565E-06 8.6 NW 4.916E-05 1.643E-05 8.801E-06 4.462E-06 1.781E-06 9.6 SSE 2.145E-05 6.929E-06 3.598E-06 1.838E-06 7.415E-07 4.0 ESE 1.450E-05 4.452E-06 2.290E-06 1.191E-06 4.921E-07 2.7 ENE 3.215E-06 1.088E-06 5.747E-07 2.885E-07 1.140E-07 6. NNE 1.015E-05 3.457E-06 1.819E-06 8.977E-07 3.486E-07 1. SSW 4.092E-05 1.295E-05 6.688E-06 3.461E-06 1.420E-06 7.8 NNW 3.826E-05 1.337E-05 7.195E-06 3.600E-06 1.413E-06 7. WSW 3.885E-05 1.214E-05 6.260E-06 3.256E-06 1.344E-06 7. WNW 4.265E-05 1.383E-05 7.329E-06 3.766E-06 1.530E-06 8. Sector .250 .500 .750 1.000 1.500 2.000 2.500 3.000 3.500 4.000 4.500 NO DECAY, UNDEPLETED NO DECAY, OPEN TERRAIN FACTORS CORRECTED USING STANDARD No Decay No Decay RELEASE POINT - GROUND LEVEL - GROUND RELEASE POINT ANNUAL AVERAGE CHI/Q (SEC/METER CUBED) ANNUAL AVERAGE
2.3S-110 Meteorology Rev. 12
STP 3 & 4 Final Safety Analysis Report 10.0 37.7 2134.0 .0 0E-08 8.477E-09 6.970E-09 5.887E-09 5.075E-09 4.446E-09 6E-08 1.157E-08 9.541E-09 8.076E-09 6.976E-09 6.121E-09 0E-09 5.250E-09 4.277E-09 3.583E-09 3.067E-09 2.670E-09 7E-09 2.042E-09 1.684E-09 1.426E-09 1.232E-09 1.081E-09 .000 30.000 35.000 40.000 45.000 50.000 56E-08 1.238E-0886E-08 1.021E-08 1.424E-08 8.650E-09 1.176E-08 7.475E-09 9.976E-09 6.562E-09 8.631E-09 7.585E-09 44E-09 4.503E-0960E-09 3.723E-09 4.816E-09 3.160E-0968E-09 3.969E-09 2.735E-09 5.917E-09 3.359E-09 2.405E-09 4.865E-09 2.900E-09 4.109E-09 2.545E-09 3.542E-09 3.103E-09 73E-08 1.319E-08 1.080E-08 9.088E-09 7.808E-09 6.820E-09 05E-09 1.187E-09 9.720E-10 8.182E-10 7.033E-10 6.145E-10 522E-08 1.213E-08 1.002E-08 8.494E-09 7.348E-09 6.456E-09 583E-08 1.255E-08 1.032E-08 8.716E-09 7.514E-09 6.583E-09 194E-08 9.353E-09 7.615E-09 6.376E-09 5.455E-09 4.746E-09 845E-09 2.229E-09 1.815E-09 1.521E-09 1.301E-09 1.133E-09 035E-09 8.149E-10 6.666E-10 5.605E-10 4.813E-10 4.202E-10 /Q Values at the Standard Radial Distances and Distance-Segment and Distance-Segment Distances Radial at the Standard Values /Q χ REP. WIND HEIGHT (METERS) WIND REP. BUILDING HEIGHT (METERS) (SQ.METERS) BLDG.MINCHESCRS.SEC.AREA (CAL/SEC) EMISSION RATE HEAT Boundaries (Continued) DISTANCE IN MILES FROM THE SITE DISTANCE .00 .00 .00 /Q at Various Distances Various /Q at χ Table 2.3S-28 XOQDOQ-Predicted Annual Averate Annual Averate 2.3S-28 XOQDOQ-Predicted Table S 1.015E-07 5.336E-08 3.517E-08 2.067E-08 1.424E-08 1.07 E 2.355E-08 1.249E-08 8.280E-09 4.908E-09 3.403E-09 2.56 N 7.092E-08 3.620E-08 2.338E-08 1.337E-08 9.046E-09 6.70 W 1.335E-07 7.085E-08 4.700E-08 2.786E-08 1.931E-08 1.45 SE 5.603E-08 2.965E-08 1.963E-08 1.161E-08 8.042E-09 6.0 NE 1.513E-08 7.817E-09 5.092E-09 2.949E-09 2.016E-09 1.5 SW 1.596E-07 8.530E-08 5.684E-08 3.391E-08 2.361E-08 1.7 NW 1.657E-07 8.616E-08 5.634E-08 3.276E-08 2.241E-08 1.6 ESE 5.018E-08 2.684E-08SSE 1.790E-08 1.069E-08 7.110E-08 7.454E-09 3.733E-08 5.6 2.458E-08 1.444E-08 9.947E-09 7.4 ENE 1.039E-08 5.380E-09 3.509E-09 2.034E-09 1.388E-09 1. NNE 3.024E-08 1.542E-08 9.945E-09 5.680E-09 3.843E-09 2. SSW 1.420E-07 7.544E-08 5.008E-08 2.973E-08 2.062E-08 1.5 NNW 1.254E-07 6.427E-08 4.159E-08 2.382E-08 1.613E-08 1. WSW 1.365E-07 7.287E-08 4.852E-08 2.892E-08 2.012E-08 1. WNW 1.490E-07 7.856E-08 5.186E-08 3.054E-08 2.107E-08 1. Sector 5.000 7.500 10.000 15.000 20.000 25 RELEASE HEIGHT (METERS) RELEASE HEIGHT DIAMETER (METERS) EXIT VELOCITY (METERS) VENT AND BUILDING PARAMETERS: No Decay No Decay CHI/Q (SEC/METER CUBED) ANNUAL AVERAGE
Meteorology 2.3S-111 Rev. 12
STP 3 & 4 Final Safety Analysis Report MILES FROM THE SITE 5.597E-08 2.104E-08 1.075E-08 6.988E-09 5.083E-09 7.417E-08 2.831E-08 1.463E-08 9.564E-09 6.985E-09 1.308E-08 4.988E-09 2.580E-09 1.688E-09 1.234E-09 3.822E-08 1.367E-08 6.746E-09 4.291E-09 3.073E-09 7 7.896E-087 3.020E-08 8.917E-08 1.564E-08 3.443E-08 1.024E-08 1.794E-08 7.485E-09 1.179E-08 8.642E-09 8 2.806E-088 1.086E-08 3.106E-08 5.670E-098 1.181E-08 3.731E-09 3.917E-08 6.091E-09 2.738E-09 1.470E-08 3.978E-09 7.509E-09 2.904E-09 4.878E-09 3.547E-09 7 9.059E-08 3.340E-08 1.683E-08 1.083E-08 7.821E-09 07 7.619E-08 2.937E-08 1.529E-08 1.004E-08 7.357E-09 07 6.778E-08 2.435E-08 1.202E-08 7.640E-09 5.465E-09 08 1.628E-08 5.812E-09 2.865E-09 1.821E-09 1.304E-09 Boundaries /Q Values at the Standard Radial Distances and Distance-Segment and Distance-Segment Distances Radial at the Standard Values /Q χ SEGMENT BOUNDARIES IN - NO INTERMITTENT RELEASES /Q at Various Segments /Q at Various χ Table 2.3S-28 XOQDOQ-Predicted Annual Averate Annual Averate 2.3S-28 XOQDOQ-Predicted Table S 5.022E-06 1.184E-06 3.776E-07 1.947E-07 1.228E-07 E 1.120E-06 2.668E-07 8.622E-08 4.480E-08 2.842E-08 N 4.161E-06 9.326E-07 2.808E-07 1.403E-07 8.661E-08 W 6.239E-06 1.499E-06 4.869E-07 2.535E-07 1.611E-07 SE 2.680E-06 6.384E-07 2.058E-07 1.068E-07 6.766E-0 NE 8.418E-07 1.908E-07 5.853E-08 2.957E-08 1.841E-08 8.231E-09 3.011E-09 1.514E-09 9.748E-10 7.044E-10 SW 7.243E-06 1.748E-06 5.746E-07 3.011E-07 1.922E-0 NW 8.567E-06 2.013E-06 6.296E-07 3.212E-07 2.011E-0 ESE 2.282E-06 5.495E-07SSE 1.806E-07 9.465E-08 3.556E-06 6.041E-0 8.349E-07 2.653E-07 1.366E-07 8.606E-0 ENE 5.616E-07 1.293E-07 3.994E-08 2.024E-0808 1.263E- 5.661E-09 2.075E-09 1.041E-09 6.686E-10 4.821E-10 NNE 1.773E-06 3.979E-07 1.198E-07 5.983E-08 3.694E- SSW 6.646E-06 1.590E-06 5.170E-07 2.694E-07 1.712E-0 NNW 6.970E-06 1.606E-06 4.902E-07 2.466E-07 1.529E- WSW 6.231E-06 1.501E-06 4.925E-07 2.578E-07 1.644E- WNW 7.191E-06 1.718E-06 5.511E-07 2.850E-0707 1.802E- 8.236E-08 3.107E-08 1.591E-08 1.034E-08 7.525E-09 NO DECAY, UNDEPLETED NO DECAY, Direction Direction Sitefrom .5-1 1-2 2-3 3-4 4-5 5-10 10-20 20-30 30-40 40-50 No Decay No Decay RELEASE POINT - GROUND LEVEL - GROUND RELEASE POINT CHI/Q (SEC/METER CUBED) FOR EACH SEGMENT XOQDOQ - STP (1997, 1999, 2000 Met Data) Data) Met 2000 1999, XOQDOQ - STP (1997,
2.3S-112 Meteorology Rev. 12
STP 3 & 4 Final Safety Analysis Report 3E-09 1.415E-09 9.265E-10 6.519E-10 4.831E-10 3.723E-10 7E-09 1.264E-09 8.278E-10 5.825E-10 4.317E-10 3.327E-10 2E-09 2.557E-09 1.674E-09 1.178E-09 8.731E-10 6.728E-10 3E-10 1.727E-107E-10 1.131E-10 2.153E-10 7.958E-11 1.410E-10 5.898E-11 9.920E-11 4.545E-11 7.352E-11 5.666E-11 98E-09 1.412E-0926E-09 9.244E-10 1.252E-09 6.505E-10 8.196E-10 4.820E-10 5.767E-10 3.715E-10 4.274E-10 3.293E-10 60E-09 2.744E-09 1.797E-09 1.264E-09 9.369E-10 7.220E-10 05E-10 4.125E-10 2.701E-10 1.900E-10 1.408E-10 1.085E-10 16E-10 3.778E-1030E-09 2.474E-10 6.065E-10 1.741E-1015E-09 3.971E-10 1.290E-10 1.069E-09 2.794E-10 9.941E-11 6.998E-10 2.071E-10 4.924E-10 1.596E-10 3.649E-10 2.812E-10 844E-09 1.086E-09 7.111E-10 5.004E-10 3.708E-10 2.858E-10 873E-09 1.692E-09 1.108E-09 7.795E-10 5.776E-10 4.451E-10 748E-09 2.796E-09 1.831E-09 1.288E-09 9.547E-10 7.357E-10 668E-09 9.819E-10 6.429E-10 4.524E-10 3.353E-10 2.584E-10 AT FIXED POINTS BY DOWNWIND SECTORS AT es at the Standard Radial Distances and Distance-Segment Distance-Segment and Distances Radial Standard at the es Boundaries DISTANCES IN MILES DISTANCES - NO INTERMITTENT RELEASES RELATIVE DEPOSITION PER UNIT AREA (M**-2) RELATIVE S 1.634E-07 5.526E-08 2.837E-08 1.349E-08 4.845E-09 2.40 E 2.487E-08 8.409E-09 4.318E-09 2.053E-09 7.373E-10 3.65 N 2.953E-07 9.987E-08 5.128E-08 2.438E-08 8.756E-09 4.34 W 1.460E-07 4.938E-08 2.535E-08 1.205E-08 4.330E-09 2.14 Table 2.3S-29 XOQDOQ-Predicted Annual Average D/Q Valu Annual Average XOQDOQ-Predicted 2.3S-29 Table SE 7.005E-08 2.369E-08 1.216E-08 5.782E-09 2.077E-09 1.0 NE 4.764E-08 1.611E-08 8.272E-09 3.933E-09 1.413E-09 7.0 SW 1.446E-07 4.889E-08 2.510E-08 1.193E-08 4.286E-09 2.1 NW 3.169E-07 1.072E-07 5.502E-08 2.616E-08 9.396E-09 4.6 ESE 4.363E-08 1.475E-08SSE 7.576E-09 3.602E-09 1.234E-07 1.294E-09 4.174E-08 6.4 2.143E-08 1.019E-08 3.660E-09 1.8 ENE 1.995E-08 6.746E-09 3.464E-09 1.647E-09 5.915E-10 2.93 NNE 1.134E-07 3.835E-08 1.969E-08 9.361E-09 3.363E-09 1. SSW 1.631E-07 5.514E-08 2.831E-08 1.346E-08 4.835E-09 2.3 NNW 3.229E-07 1.092E-07 5.607E-08 2.666E-08 9.575E-09 4. WSW 1.254E-07 4.242E-08 2.178E-08 1.035E-08 3.719E-09 1. WNW 1.954E-07 6.607E-08 3.393E-08 1.613E-08 5.793E-09 2. Direction Direction from Site .25 .50 .75 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 D/Qs at Various Distances Various D/Qs at LEVEL - GROUND RELEASE POINT OPEN TERRAIN FACTORS CORRECTED USING STANDARD
Meteorology 2.3S-113 Rev. 12
STP 3 & 4 Final Safety Analysis Report 4E-12 1.780E-12 1.337E-12 1.039E-12 8.302E-13 6.776E-13 8E-12 5.014E-12 3.765E-12 2.928E-12 2.339E-12 1.909E-12 59E-12 3.123E-12 2.345E-12 1.824E-12 1.457E-12 1.189E-12 59E-12 3.410E-12 2.561E-12 1.991E-12 1.590E-12 1.298E-12 166E-11 2.269E-11 1.703E-11 1.324E-11 1.058E-11 8.636E-12 633E-11 1.170E-11629E-11 8.784E-12 1.167E-11 6 .830E-12444E-11 8.764E-12 5.456E-12 1.035E-11 6 .815E-12 4.453E-12 253E-11 7.770E-12 5.443E-12 8.979E-12 6 .042E-12 4.443E-12 459E-11 6.742E-12 4.826E-12 1.045E-11 5.242E-12 3.939E-12 7.849E-12 4.188E-12 6 .103E-12 3.418E-12 4.875E-12 3.979E-12 233E-11 8.835E-12 6.634E-12 5.158E-12 4.121E-12 3.363E-12 950E-11 2.114E-11133E-11 1.587E-11 8.118E-12 1.234E-11 6.096E-12 9.859E-12 4.740E-12 8.047E-12 3.786E-12 3.090E-12 993E-12 1.428E-12 1.072E-12 8.337E-13 6.660E-13 5.436E-13 1.952E-11 1.399E-11 1.050E-11 8.166E-12 6.523E-12 5.324E-12 3.226E-11 2.312E-11 1.736E-11 1.350E-11 1.078E-11 8.799E-12 es at the Standard Radial Distances and Distance-Segment Distance-Segment and Distances Radial Standard at the es 0 25.00 30.00 35.00 40.00 45.00 50.00 DISTANCES IN MILES DISTANCES Boundaries (Continued) S 2.958E-10 1.314E-10 7.959E-11 4.023E-11 2.435E-11 1. E 4.501E-11 1.999E-11 1.211E-11 6.122E-12 3.705E-12 2.48 N 5.345E-10 2.374E-10 1.438E-10 7.270E-11 4.400E-11 2. W 2.643E-10 1.174E-10 7.112E-11 3.595E-11 2.176E-11 1. Table 2.3S-29 XOQDOQ-Predicted Annual Average D/Q Valu Annual Average XOQDOQ-Predicted 2.3S-29 Table SE 1.268E-10 5.632E-11 3.412E-11 1.724E-11 1.044E-11 6.99 NE 8.623E-11 3.830E-11 2.320E-11 1.173E-11 7.098E-12 4.7 SW 2.616E-10 1.162E-10 7.041E-11 3.559E-11 2.154E-11 1. NW 5.736E-10 2.548E-10 1.543E-10 7.802E-11 4.722E-11 3. ESE 7.897E-11 3.508E-11 2.125E-11 1.074E-11 6.501E-12 4.3 SSE 2.234E-10 9.924E-11 6.012E-11 3.039E-11 1.839E-11 1. ENE 3.611E-11 1.604E-11 9.716E-12 4.911E-12 2.972E-12 1. NNE 2.053E-10 9.118E-11 5.524E-11 2.792E-11 1.690E-11 1. SSW 2.951E-10 1.311E-10 7.941E-11 4.014E-11 2.429E-11 1. NNW 5.845E-10 2.596E-10 1.573E-10 7.950E-11 4.811E-11 WSW 2.270E-10 1.009E-10 6.109E-11 3.088E-11 1.869E-11 1. WNW 3.536E-10 1.571E-10 9.516E-11 4.810E-11 2.911E-11 Direction Direction Sitefrom 5.00 7.50 10.00 15.00 20.0 D/Qs at Various Distances Various D/Qs at
2.3S-114 Meteorology Rev. 12
STP 3 & 4 Final Safety Analysis Report 10.0 37.7 2134.0 .0 3E-12 2.586E-12 1.601E-12 es at the Standard Radial Distances and Distance-Segment Distance-Segment and Distances Radial Standard at the es 0 4.224E-11 1.222E-11 4.84 0 3.869E-110 1.119E-11 6.211E-11 4.436E-12 1.797E-11 2.369E-12 7.122E-12 1.466E-12 3.803E-12 2.354E-12 11 1.769E-1111 5.117E-12 2.205E-11 2.028E-12 6.379E-12 1.083E-12 2.528E-12 6.704E-13 1.350E-12 8.357E-13 10 1.112E-1010 3.218E-11 1.295E-10 1.275E-11 3.746E-11 6.810E-12 1.485E-11 4.215E-12 7.928E-12 4.907E-12 10 2.863E-10 8.283E-11 3.283E-11 1.753E-11 1.085E-11 10 1.006E-10 2.909E-11 1.153E-11 6.157E-12 3.811E-12 -10 1.446E-10-10 4.183E-11 1.282E-10 1.658E-11 3.708E-11 8.852E-12 1.470E-11 5.479E-12 7.848E-12 4.858E-12 -10 2.810E-10 8.129E-11 3.222E-11 1.721E-11 1.065E-11 -10 1.094E-10 3.166E-11 1.255E-11 6.701E-12 4.148E-12 Boundaries UNIT AREA (M**-2) BY DOWNWIND SECTORS REP. WIND HEIGHT (METERS) WIND REP. BUILDING HEIGHT (METERS) (SQ.METERS) BLDG.MINCHESCRS.SEC.AREA (CAL/SEC) EMISSION RATE HEAT SEGMENT BOUNDARIES IN MILES - NO INTERMITTENT RELEASES .00 .00 .00 RELATIVE DEPOSITION PER RELATIVE S 2.773E-08 5.681E-09 1.483E-09 6.661E-1010 3.768E- 1.449E-10 4.192E-11 1.661E-11 8.872E-12 5.491E-12 E 4.220E-09 8.645E-10 2.257E-10 1.014E-10 5.734E- N 5.012E-08 1.027E-08 2.680E-09 1.204E-0910 6.809E- 2.619E-10 7.575E-11 3.002E-11 1.603E-11 9.924E-12 W 2.478E-08 5.076E-09 1.325E-09 5.951E-10 3.367E- Table 2.3S-29 XOQDOQ-Predicted Annual Average D/Q Valu Annual Average XOQDOQ-Predicted 2.3S-29 Table SE 1.189E-08 2.435E-09 6.357E-10 2.855E-10 1.615E-1 NE 8.085E-09 1.656E-09 4.323E-10 1.942E-10 1.098E-1 SW 2.453E-08 5.025E-09 1.312E-09 5.892E-10 3.333E NW 5.378E-08 1.102E-08 2.876E-09 1.292E-09 7.307E ESE 7.405E-09 1.517E-09SSE 3.960E-10 1.778E-10 2.095E-08 1.006E-1 4.291E-09 1.120E-09 5.031E-10 2.846E ENE 3.386E-09 6.935E-10 1.810E-10 8.131E-11 4.600E- NNE 1.925E-08 3.942E-09 1.029E-09 4.622E-10 2.615E- SSW 2.767E-08 5.668E-09 1.480E-09 6.646E-10 3.760E NNW 5.480E-08 1.123E-08 2.930E-09 1.316E-09 7.446E- WSW 2.129E-08 4.360E-09 1.138E-09 5.112E-10 2.892E- WNW 3.316E-08 6.792E-09 1.773E-09 7.964E-1010 4.505E- 1.732E-10 5.012E-11 1.986E-11 1.061E-11 6.566E-12 RELEASE HEIGHT (METERS) RELEASE HEIGHT DIAMETER (METERS) EXIT VELOCITY (METERS) Direction Direction Sitefrom .5-1 1-2 2-3 3-4 4-5 5-10 10-20 20-30 30-40 40-50 D/Qs at Various Segments Various D/Qs at LEVEL - GROUND RELEASE POINT VENT AND BUILDING PARAMETERS:
Meteorology 2.3S-115 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.3S-1 Climatological Observing Stations Near the STP Site STP Near the Observing Stations Climatological 2.3S-1 Figure
2.3S-116 Meteorology Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.3S-2 STP 3 & 4 10-Meter Level 3-year Composite Wind Rose - Annual (1997, 1999, and 2000) 1999, (1997, Rose - Annual Wind 3-year Composite Level 10-Meter STP 3 & 4 Figure 2.3S-2
Meteorology 2.3S-117 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.3S-3 STP 3 & 4 10-Meter Level 3-Year Composite Wind Rose - Winter (1997, 1999, and 2000) and 1999, - Winter (1997, Wind Rose Composite 3-Year Level STP 3 & 4 10-Meter Figure 2.3S-3
2.3S-118 Meteorology Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.3S-4 STP 3 & 4 10-Meter Level 3-Year Composite Wind Rose - Spring (1997, 1999, and 2000) 1999, - Spring (1997, Wind Rose Composite Level 3-Year STP 3 & 4 10-Meter Figure 2.3S-4
Meteorology 2.3S-119 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.3S-5 STP 3 & 4 10-Meter Level 3-Year Composite Wind Rose - Summer (1997, 1999, and 2000) 1999, (1997, - Summer Rose Wind 3-Year Composite 4 10-Meter Level & 2.3S-5 STP 3 Figure
2.3S-120 Meteorology Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.3S-6 STP 3 & 4 10-Meter Level 3-Year Composite Wind Rose - Autumn (1997, 1999, and 2000) and 1999, (1997, - Autumn Wind Rose Composite 3-Year Level STP 3 & 4 10-Meter Figure 2.3S-6
Meteorology 2.3S-121 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.3S-7 STP 3 & 4 10-Meter Level 3-Year Composite Wind Rose - January (1997, 1999, and 2000) - Sheet 1 of 12 - Sheet and 2000) 1999, (1997, - January Rose Wind 3-Year Composite 4 10-Meter Level & 2.3S-7 STP 3 Figure
2.3S-122 Meteorology Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.3S-7 STP 3 & 4 10-Meter Level 3-Year Composite Wind Rose - February (1997, 1999, and 2000) - Sheet 2 of 12 - Sheet 2 2000) and 1999, - February (1997, Wind Rose Composite Level 3-Year STP 3 & 4 10-Meter Figure 2.3S-7
Meteorology 2.3S-123 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.3S-7 STP 3 & 4 10-Meter Level 3-Year Composite Wind Rose - March (1997, 1999, and 2000) - Sheet 3 of 12 - Sheet 3 2000) and 1999, - March (1997, Wind Rose Composite 3-Year Level STP 3 & 4 10-Meter Figure 2.3S-7
2.3S-124 Meteorology Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.3S-7 STP 3 & 4 10-Meter Level 3-Year Composite Wind Rose - April (1997, 1999, and 2000) - Sheet 4 of 12 - Sheet 4 2000) 1999, and (1997, April Wind Rose - Composite 3-Year Level STP 3 & 4 10-Meter Figure 2.3S-7
Meteorology 2.3S-125 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.3S-7 STP 3 & 4 10-Meter Level 3-Year Composite Wind Rose - May (1997, 1999, and 2000) - Sheet 5 of 12 - Sheet and 2000) 1999, - May (1997, Rose Wind 3-Year Composite 10-Meter Level & 4 2.3S-7 STP 3 Figure
2.3S-126 Meteorology Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.3S-7 STP 3 & 4 10-Meter Level 3-Year Composite Wind Rose - June (1997, 1999, and 2000) - Sheet 6 of 12 - Sheet 6 2000) and 1999, - June (1997, Wind Rose Composite Level 3-Year STP 3 & 4 10-Meter Figure 2.3S-7
Meteorology 2.3S-127 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.3S-7 STP 3 & 4 10-Meter Level 3-Year Composite Wind Rose - July (1997, 1999, and 2000) - Sheet 7 of 12 - Sheet and 2000) 1999, (1997, Rose - July Wind 3-Year Composite & 4 10-Meter Level STP 3 2.3S-7 Figure
2.3S-128 Meteorology Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.3S-7 STP 3 & 4 10-Meter Level 3-Year Composite Wind Rose - August (1997, 1999, and 2000) - Sheet 8 of 12 - Sheet and 2000) 1999, (1997, Rose - August Wind 3-Year Composite 3 & 4 10-Meter Level STP 2.3S-7 Figure
Meteorology 2.3S-129 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.3S-7 STP 3 & 4 10-Meter Level 3-Year Composite Wind Rose - September (1997, 1999, and 2000) - Sheet 9 of 12 - Sheet and 2000) 1999, (1997, - September Rose Wind 3-Year Composite 4 10-Meter Level & 2.3S-7 STP 3 Figure
2.3S-130 Meteorology Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.3S-7 STP 3 & 4 10-Meter Level 3-Year Composite Wind Rose - October (1997, 1999, and 2000) - Sheet 10 of 12 10 of - Sheet and 2000) 1999, (1997, - October Wind Rose 3-Year Composite Level 10-Meter STP 3 & 4 Figure 2.3S-7
Meteorology 2.3S-131 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.3S-7 STP 3 & 4 10-Meter Level 3-Year Composite Wind Rose - November (1997, 1999, and 2000) - Sheet 11 of 12 - Sheet 11 2000) and 1999, (1997, - November Wind Rose Composite 3-Year Level STP 3 & 4 10-Meter Figure 2.3S-7
2.3S-132 Meteorology Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.3S-7 STP 3 & 4 10-Meter Level 3-Year Composite Wind Rose - December (1997, 1999, and 2000) - Sheet 12 of 12 - Sheet 12 2000) and 1999, (1997, December Wind Rose - Composite 3-Year Level STP 3 & 4 10-Meter Figure 2.3S-7
Meteorology 2.3S-133 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.3S-8 STP 3 & 4 60-Meter Level 3-Year Composite Wind Rose - Annual (1997, 1999, and 2000) 1999, (1997, - Annual Rose Wind 3-Year Composite 60-Meter Level & 4 2.3S-8 STP 3 Figure
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STP 3 & 4 Final Safety Analysis Report Figure 2.3S-9 STP 3 & 4 60-Meter Level 3-Year Composite Wind Rose - Winter (1997, 1999, and 2000) and 1999, - Winter (1997, Wind Rose Composite 3-Year Level STP 3 & 4 60-Meter Figure 2.3S-9
Meteorology 2.3S-135 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.3S-10 STP 3 & 4 60-Meter Level 3-Year Composite Wind Rose - Spring (1997, 1999, and 2000) 1999, - Spring (1997, Wind Rose 3-Year Composite Level 60-Meter STP 3 & 4 Figure 2.3S-10
2.3S-136 Meteorology Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.3S-11 STP 3 & 4 60-Meter Level 3-Year Composite Wind Rose - Summer (1997, 1999, and 2000) 1999, (1997, Rose - Summer Wind 3-Year Composite & 4 60-Meter Level STP 3 2.3S-11 Figure
Meteorology 2.3S-137 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.3S-12 STP 3 & 4 60-Meter Level 3-Year Composite Wind Rose - Autumn (1997, 1999, and 2000) and 1999, - Autumn (1997, Wind Rose Composite Level 3-Year STP 3 & 4 60-Meter Figure 2.3S-12
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STP 3 & 4 Final Safety Analysis Report Figure 2.3S-13 STP 3 & 4 60-Meter Level 3-Year Composite Wind Rose - January (1997, 1999, and 2000) - Sheet 1 of 12 1 of Sheet 2000) - and 1999, (1997, Rose - January Wind 3-Year Composite & 4 60-Meter Level STP 3 2.3S-13 Figure
Meteorology 2.3S-139 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.3S-13 STP 3 & 4 60-Meter Level 3-Year Composite Wind Rose - February (1997, 1999, and 2000) - Sheet 2 of 12 - Sheet 2 2000) and 1999, - February (1997, Wind Rose 3-Year Composite Level 60-Meter STP 3 & 4 Figure 2.3S-13
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STP 3 & 4 Final Safety Analysis Report Figure 2.3S-13 STP 3 & 4 60-Meter Level 3-Year Composite Wind Rose - March (1997, 1999, and 2000) - Sheet 3 of 12 - Sheet 3 2000) 1999, and (1997, - March Wind Rose Composite Level 3-Year STP 3 & 4 60-Meter Figure 2.3S-13
Meteorology 2.3S-141 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.3S-13 STP 3 & 4 60-Meter Level 3-Year Composite Wind Rose - April (1997, 1999, and 2000) - Sheet 4 of 12 - Sheet and 2000) 1999, (1997, - April Wind Rose Composite 3-Year Level STP 3 & 4 60-Meter Figure 2.3S-13
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STP 3 & 4 Final Safety Analysis Report Figure 2.3S-13 STP 3 & 4 60-Meter Level 3-Year Composite Wind Rose - May (1997, 1999, and 2000) - Sheet 5 of 12 5 of Sheet 2000) - and 1999, - May (1997, Rose Wind 3-Year Composite 4 60-Meter Level & 2.3S-13 STP 3 Figure
Meteorology 2.3S-143 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.3S-13 STP 3 & 4 60-Meter Level 3-Year Composite Wind Rose - June (1997, 1999, and 2000) - Sheet 6 of 12 - Sheet 6 2000) and (1997, 1999, - June Wind Rose Composite Level 3-Year STP 3 & 4 60-Meter Figure 2.3S-13
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STP 3 & 4 Final Safety Analysis Report Figure 2.3S-13 STP 3 & 4 60-Meter Level 3-Year Composite Wind Rose - July (1997, 1999, and 2000) - Sheet 7 of 12 - Sheet 7 2000) and 1999, - July (1997, Wind Rose Composite Level 3-Year STP 3 & 4 60-Meter Figure 2.3S-13
Meteorology 2.3S-145 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.3S-13 STP 3 & 4 60-Meter Level 3-Year Composite Wind Rose - August (1997, 1999, and 2000) - Sheet 8 of 12 - Sheet and 2000) 1999, (1997, Rose - August Wind Composite 3-Year STP 3 & 4 60-Meter Level 2.3S-13 Figure
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STP 3 & 4 Final Safety Analysis Report Figure 2.3S-13 STP 3 & 4 60-Meter Level 3-Year Composite Wind Rose - September (1997, 1999, and 2000) - Sheet 9 of 12 - Sheet and 2000) 1999, (1997, Rose - September Wind 3-Year Composite & 4 60-Meter Level 3 STP 2.3S-13 Figure
Meteorology 2.3S-147 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.3S-13 STP 3 & 4 60-Meter Level 3-Year Composite Wind Rose - October (1997, 1999, and 2000) - Sheet 10 of 12 10 of Sheet 2000) - and 1999, - October (1997, Rose Wind 3-Year Composite 60-Meter Level & 4 STP 3 Figure 2.3S-13
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STP 3 & 4 Final Safety Analysis Report Figure 2.3S-13 STP 3 & 4 60-Meter Level 3-Year Composite Wind Rose - November (1997, 1999, and 2000) - Sheet 11 of 12 - Sheet 11 2000) and 1999, (1997, - November Wind Rose Composite Level 3-Year STP 3 & 4 60-Meter Figure 2.3S-13
Meteorology 2.3S-149 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.3S-13 STP 3 & 4 60-Meter Level 3-Year Composite Wind Rose - December (1997, 1999, and 2000) - Sheet 12 of 12 - Sheet 12 2000) and 1999, (1997, - December Wind Rose Composite 3-Year Level STP 3 & 4 60-Meter Figure 2.3S-13
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STP 3 & 4 Final Safety Analysis Report Figure 2.3S-14 Site Area Map (50-Mile Radius) Radius) Site Area Map (50-Mile Figure 2.3S-14
Meteorology 2.3S-151 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.3S-15 Site and Vicinity Map (5-Mile Radius) Site and Vicinity 2.3S-15 Figure
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STP 3 & 4 Final Safety Analysis Report Figure 2.3S-16 Terrain Elevation Profiles Within 50 Miles of the STP 3 & 4 Site (Sheet 1 of 8) (Sheet 1 Site the STP 3 & 4 50 Miles of Within Profiles Elevation Terrain Figure 2.3S-16
Meteorology 2.3S-153 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.3S-16 Terrain Elevation Profiles Within 50 Miles of the STP 3 & 4 Site (Sheet 2 of 8) (Sheet 2 Site the STP 3 & 4 50 Miles of Within Profiles Elevation Terrain Figure 2.3S-16
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STP 3 & 4 Final Safety Analysis Report Figure 2.3S-16 Terrain Elevation Profiles Within 50 Miles of the STP 3 & 4 Site (Sheet 3 of 8) (Sheet 3 Site the STP 3 & 4 50 Miles of Within Profiles Elevation Terrain Figure 2.3S-16
Meteorology 2.3S-155 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.3S-16 Terrain Elevation Profiles Within 50 Miles of the STP 3 & 4 Site (Sheet 4 of 8) (Sheet 4 Site the STP 3 & 4 50 Miles of Within Profiles Elevation Terrain Figure 2.3S-16
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STP 3 & 4 Final Safety Analysis Report Figure 2.3S-16 Terrain Elevation Profiles Within 50 Miles of the STP 3 & 4 Site (Sheet 5 of 8) (Sheet 5 Site the STP 3 & 4 50 Miles of Within Profiles Elevation Terrain Figure 2.3S-16
Meteorology 2.3S-157 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.3S-16 Terrain Elevation Profiles Within 50 Miles of the STP 3 & 4 Site (Sheet 6 of 8) (Sheet 6 Site the STP 3 & 4 50 Miles of Within Profiles Elevation Terrain Figure 2.3S-16
2.3S-158 Meteorology Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.3S-16 Terrain Elevation Profiles Within 50 Miles of the STP 3 & 4 Site (Sheet 7 of 8) (Sheet 7 Site the STP 3 & 4 50 Miles of Within Profiles Elevation Terrain Figure 2.3S-16
Meteorology 2.3S-159 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.3S-16 Terrain Elevation Profiles Within 50 Miles of the STP 3 & 4 Site (Sheet 8 of 8) (Sheet 8 Site the STP 3 & 4 50 Miles of Within Profiles Elevation Terrain Figure 2.3S-16
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STP 3 & 4 Final Safety Analysis Report p p Figure 2.3S-17 Site and Vicinity Map (10-Mile Radius) and Vicinity Site 2.3S-17 Figure
Meteorology 2.3S-161 Rev. 12 STP 3 & 4 Final Safety Analysis Report Figure 2.3S-18 Location of Meteorological Towers Towers of Meteorological Location Figure 2.3S-18
2.3S-162 Meteorology Rev. 12 STP 3 & 4 Final Safety Analysis Report Figure 2.3S-19 Meteorological System Block Diagram (Primary Tower - Preoperational Configuration) Configuration) - Preoperational (Primary Tower Diagram Block System Meteorological 2.3S-19 Figure
Meteorology 2.3S-163 Rev. 12 STP 3 & 4 Final Safety Analysis Report ram (Backup Tower - Preoperational Configuration) - Preoperational Tower (Backup ram Figure 2.3S-20 Meteorological System Block Diag System Meteorological Figure 2.3S-20
Mt l
2.3S-164 Meteorology Rev. 12 STP 3 & 4 Final Safety Analysis Report Figure 2.3S-21 Meteorological System Block Diagram (Primary Tower - Preoperational Configuration) Configuration) - Preoperational (Primary Tower Diagram Block System Meteorological 2.3S-21 Figure
Meteorology 2.3S-165 Rev. 12 STP 3 & 4 Final Safety Analysis Report agram (Backup Tower - Operational Configuration) Tower - Operational (Backup agram Figure 2.3S-22 Meteorological System Block Di Block System Meteorological Figure 2.3S-22
2.3S-166 Meteorology Rev. 12 STP 3 & 4 Final Safety Analysis Report
Figure 2.3S-23 Accident Release and Receptor Locations
Meteorology 2.3S-167/168
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2.4S.1 Hydrolflogic Description The following site-specific supplement addresses COL License Information Item 2.13.
2.4S.1.1 Site and Facilities The STP 3 & 4 site is located in Matagorda County, Texas near the west bank of the Colorado River, opposite river mile 14.6. It is approximately 12 miles south-southwest of Bay City, Texas, and 8 miles north-northwest of Matagorda, Texas (Figure 2.4S.1- 1). The surface elevation of the site ranges from about El. 32 to 34 ft mean sea level (MSL), which is equivalent to National Geodetic Vertical Datum of 1929 (NGVD 29), at the north boundary to between El. 15 ft to 20 ft MSL at the south boundary.
Figure 2.4S.1-2 shows the topography and hydrologic features within about 3 miles from the site based on digital data from the U.S. Geological Survey (USGS). Figure 2.4S.1-3 shows the existing (pre-development) topography of the site in more detail based on data from a recent aerial survey. Figure 2.4S.1-3 also shows various external plant structures and components. The proposed site layout and drainage system after the construction of Unit 3 & 4 is discussed in Subsection 2.4S.2. The post-development topography and major drainage features of the site are presented in Figure 2.4S.2-4.
A major feature of the site is the Main Cooling Reservoir (MCR), which is formed by a 12.4-mile-long earthfill embankment constructed above the natural ground surface. The MCR has a surface area of 7000 acres with a normal maximum operating level of El. 49 ft MSL. The MCR is not a safety-related facility. Makeup water to the MCR is supplied from the Colorado River and pumped into the MCR intermittently throughout the year via the Reservoir Makeup Pumping Facility (RMPF). A smaller separate cooling pond, referred to as the Essential Cooling Pond (ECP), serves as the ultimate heat sink for STP 1 & 2. The surface area of the ECP is 46 acres. (Reference 2.4S.1-1)
STP 3 & 4 utilizes safety-related Ultimate Heat Sinks (UHS) to remove heat load from the Reactor Service Water (RSW) system during normal, safe shutdown and the design basis accident. The UHS basin is sized for a water volume adequate for 30 days of cooling with no makeup water under the design basis accident. A UHS basin and its pump house are dedicated to each unit. Each unit has a counterflow mechanically induced draft cooling tower with six cooling tower cells, of which two cells are dedicated to each of the three RSW divisions to remove heat from their respective RCW/RSW division.The primary source of makeup water to the UHS cooling towers are site wells with the MCR as the backup source.
The critical safety-related flood levels resulting from a postulated instantaneous breach of the MCR embankment are discussed in Subsection 2.4S.4. Calculations show a maximum flood water level at the safety-related facilities, including the power block and the UHSs, to be El. 38.8 ft MSL. The Design-Basis Flood (DBF) elevation is conservatively established as 40.0 ft MSL. Specific elevations of safety-related structures and plant flood protection measures are discussed in Subsections 2.4S.2 and 2.4S.10.
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2.4S.1.2 Hydrosphere Plant interfaces with hydrosphere include the use of the MCR for nonsafety-related normal plant cooling, and the use of groundwater to supply the safety-related UHS cooling water and potable water. Makeup water for the MCR is withdrawn from the Colorado River adjacent to the site. The UHS cooling tower basin is sized to maintain a water inventory adequate for 30 days of cooling under the design basis accident with no makeup and blowdown. As discussed in Subsection 9.2.5, the UHS is designed to meet the dependability requirements, and the affected units can be safely shut down without relying on the availability of groundwater.
The conceptual model of the site hydrology presented in this section, including surface water and groundwater, is well supported by site data and is expected to realistically represent hydrologic conditions at the site. All site-related seismic and non-seismic information have been taken into account as they related to the hydrologic description.
2.4S.1.2.1 Surface Water 2.4S.1.2.1.1 Colorado River Basin
General Description The Colorado River Basin extends across the middle of Texas, from the southeastern portion of New Mexico to Matagorda Bay at the Gulf of Mexico. The total drainage area of the Colorado River is 42,318 sq. miles, 11,403 sq. miles of which is considered non- contributory to the river water supply. The Lower Colorado River Basin is the part of the river system from Lake O.H. Ivie to the Gulf Coast (Figure 2.4S.1-4) and comprises approximately 22,682 sq. miles of drainage area (Reference 2.4S.1-2). The Upper Colorado River Basin has a drainage area of approximately 19,636 sq. miles. There are six major tributaries with drainage areas greater than 1000 sq. miles that contribute to the Colorado River: Beals Creek and Concho River in the upper Colorado River Basin and San Saba, Llano, Pedernales Rivers, and Pecan Bayou in the lower Colorado River Basin. All six major tributaries, and approximately 90% of the entire contributing drainage for the river, occur upstream of Mansfield Dam near Austin. Downstream of Austin, there are only two tributaries with drainage areas greater than 200 sq. miles: Barton Creek and Onion Creek in Travis County (Reference 2.4S.1-3).
The Colorado Basin lies within the warm-temperate/subtropical zone, and its subtropical climate is typified by dry winters and humid summers. Spring and fall are both wet seasons in this region with rainfall peaks in May and September. The spring rains are produced by convective thunderstorms, which result in high intensity, short duration precipitation events with rapid runoff. The fall rains are primarily governed by tropical storms and hurricanes that originate in the Caribbean Sea or the Gulf of Mexico. These rains pose flooding risks to the Gulf Coast from Louisiana to Mexico. The spatial rainfall distribution in this region varies from an annual amount of 44 inches at the coast to 24 inches in the northwestern portion of the region (Reference 2.4S.1-3).
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The Colorado River Basin is located in a semi-arid region; its hydrologic characteristics are closely linked to the weather in this area, which has been described as a “continuous drought periodically interrupted by floods” (Reference 2.4S.1-4).
Stream flow gauging data collected in the Colorado River since the early 1900s show that there has been a major drought in almost every decade of the twentieth century. Major droughts in the basin cause stock ponds and small reservoirs to go dry and large reservoirs, such as Lake Travis, formed by Mansfield Dam, to significantly drop their storage levels, even to one third of their storage capacity. During the 30-year period from 1941 to 1970, there have been three major statewide droughts, from 1947 to 1948, from 1950 to 1957, and from 1960 to 1967. The most severe of these droughts occurred from 1950 to 1957, when 94 percent of the counties in the state were declared disaster areas (Reference 2.4S.1-4). The discussion about maintaining sufficient water supply to STP 3 & 4 during severe drought conditions is presented in Subsection 2.4S.11. With support of water management plan between the Lower Colorado River Authority (LCRA) and STP, the MCR is capable of supplying the existing STP 1 & 2 and STP 3 & 4 units during low flow conditions in the Colorado River. Since the primary source of makeup water to the UHS cooling tower basin for STP 3 & 4 is onsite groundwater wells, the low water considerations does not affect the dependability of the source of makeup water for the UHS, and the deep aquifer has sufficient capacity to supply makeup water to the UHS basin as documented in Subsection 2.4S.12.
A drought cycle is often followed by one or more flooding events. Due to very limited vegetative cover, rocky terrain, and steep channels, runoff in the Upper Colorado River is high and rapid, producing fast moving and high-peak floods. The terrain in the Lower Colorado River basin is flatter with greater vegetative cover and wider floodplains, which reduces the velocity of floods. The Hill Country watershed of the Lower Colorado River has been characterized as “Flash Flood Alley,” meaning that the lower Colorado River Basin is one of the regions most prone to flash flood damage. There are two major phenomena that contribute to the high flooding potential in this region. First, thin soils and steep slopes in the upper Colorado River Basin promote rapid runoff from the watershed during heavy rain events. Second, the large and relatively steep drainage area of the Hill Country can receive runoff from hundreds of miles away, transforming heavy rains into flood waters with destructive potential. More than 80 floods have been recorded in this region since the mid-1800s. During these events, water levels exceeded the river flood stage and inundated dry lands. The most intense localized flash flood in the Lower Colorado region in recent history occurred on May 24, 1981 in Austin (Reference 2.4S.1-3).
Major reservoirs in the Colorado River Basin with storage capacity greater than 10,000 acre-feet are summarized in Table 2.4S.1-1 (Reference 2.4S.1-5), which are sorted in order of descending storage capacity. The locations of some major dams are shown in Figure 2.4S.1-5. Because of the high risk of flooding in the Lower Colorado River basin, a system of dams and lakes has been developed along the river primarily to manage floodwaters, but also to conserve and convey water supplies. The Lower Colorado River Authority (LCRA) operates six dams on the Lower Colorado River: Buchanan, Inks, Wirtz, Starcke, Mansfield, and Tom Miller (Figure 2.4S.1-6). These
Hydrolflogic Description 2.4S.1-3 Rev. 12
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dams form the six Highland Lakes: Buchanan, Inks, LBJ, Marble Falls, Travis, and Austin (Reference 2.4S.1-6).
Buchanan Dam and Mansfield Dam are the two major dams on the Lower Colorado River that may influence conditions at STP site 3 & 4. Mansfield Dam, forming Lake Travis, is located approximately 28 miles upstream from Austin. Mansfield Dam is the largest reservoir and the most downstream existing major control structure on the Colorado River (Reference 2.4S.1-6). Buchanan Dam is another large dam on the main stream of the Colorado River. Its primary purpose is water supply and generation of hydroelectric power. Table 2.4S.1-2 gives the pertinent characteristics of these two major dams and Figure 2.4S.1-7 gives the area-capacity curves of Lake Travis and Lake Buchanan. The characteristics of these two dams are also used in the dam break analysis presented in Subsection 2.4S.4.
The seismic design criteria for these two dams are not readily available. The dam break analysis presented in Subsection 2.4S.4 is performed under very conservative assumptions. Specifically, all dams on the Colorado River and its tributaries upstream of Buchanan Dam (with top-of-dam capacity over 5000 AF) would fail in such a manner that their flood flow, expressed in terms of their respective top-of-dam storage volumes, would arrive at Lake Buchanan at approximately the same time, triggering the failure of Buchanan Dam. The dam break flood flow from Buchanan Dam would then propagate downstream to Lake Travis, overtopping Mansfield Dam and causing it to fail. Further, the dam failures were postulated to occur coincidentally with a 2-year design wind event and a Standard Project Flood (SPF) event, more severe than a 500-year flood or a one-half probable maximum flood (PMF) dams as required by ANSI/ANS-2.8.
In accordance with the spillway design criteria for dams as defined in Rule 299.14 Title 30 of the Texas Administrative Code (Reference 2.4S.1-14), large dams with high hazard potential, such as Buchanan and Mansfield Dams, were either designed or have been upgraded to accommodate and sustain their respective Probable Maximum Flood (PMF). With the completion of Simon Freese Dam in 1989, normal flows and flood flows in the Colorado River upstream of Mansfield Dam are regulated by 27 major reservoirs, including Lake Travis (Reference 2.4S.1-5).
Even though there are several dams upstream of Mansfield Dam, Mansfield Dam provides most of the floodwater storage capacity. The other dams pass floodwaters downstream to Lake Travis, where the water is stored in a flood pool until it can be released safely downstream. Tom Miller Dam at Austin is downstream of Lake Travis. It impounds a portion of the Colorado River known as Lake Austin; however, because of the small storage capacity of its reservoir, it affords no major control of flood flows. Lake Travis and Lake Buchanan also serve as water supply reservoirs. Lake Travis has a water supply storage capacity of approximately 1,132,400 acre-feet and Lake Buchanan has a water supply storage capacity of approximately 875,000 acre-feet. With a combined capacity of about 2 million acre-feet, the two lakes store water for communities, industry and aquatic life along the river, as well as supply irrigation water for the agricultural industry near the Gulf Coast (Reference 2.4S.1-7).
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The Colorado River near the Site For large peak flows the attenuation of peak discharges downstream from the City of Columbus (see Figure 2.4S.1-8) becomes more pronounced than for smaller flows. This phenomenon is explained by a comparison of the floodplain and river valley complex of the areas above and below Columbus. Above Columbus, the width of the floodplain varies from about 2.5 to 5.5 miles. The slope of the floodplain in the direction normal to the channel varies from about 5 ft/mile to 12 ft/mile. Also, the floodplain is in a well-defined valley, which provides relatively little storage of storm runoff, especially during floods of greater magnitudes. Below Columbus, the floodplain width varies from 4 to 8 miles, and its side slopes average between 0.5 ft/mile and 1.5 ft/mile. In this area, no discernible valley exists, and the floodwaters can spill over beyond the basin divide causing interbasin spillage. Thus, this part of the basin provides significant flood peak attenuation. (References 2.4S.1-1 and 2.4S.1-8)
Table 2.4S.1-3 gives pertinent data of seven stream-flow gauging stations downstream of Mansfield Dam, including the mean, highest and lowest average annual flow for the period of record. The locations of these gauges are shown on Figure 2.4S.1-8 (Reference 2.4S.1-8). The streamflow gauging station nearest to the STP 3 & 4 site is located approximately 16 miles upstream of the STP site and about 2.8 miles west of Bay City, at river mile 32.5 on the Colorado River. Records of stage at this station have been collected since the installment of the gauge in April 1948 till present. Based on the historical data, for the water years 1948 to 2004, the highest annual stream flow at this station is 14,270 cfs (cubic feet per second), the lowest annual flow is 375 cfs, and the mean annual flow is about 2628 cfs.
Figure 2.4S.1-9 shows the flood inundated areas delineated by the Federal Emergency Management Agency (FEMA) in the area near the site of STP 3 & 4. The map shows different flood prone areas indicated as zones A, B, and C for flood insurance purposes. Zone A indicates areas of special flood hazard; zone B includes areas of moderate flood hazards, and zone C areas of minimal flood hazards. The site of STP 3 & 4 is located in Zone C, suggesting minimal flooding possibility.
2.4S.1.2.1.2 Little Robbins Slough Little Robbins Slough (see Figure 2.4S.1-2) is a significant hydrologic feature near the STP site. It is an intermittent stream located nine miles northwest of Matagorda in southwestern Matagorda County and runs south for 6.5 miles to the point where it joins Robbins Slough, a brackish marsh, which meanders four more miles to the Gulf Intracoastal Waterway (Reference 2.4S.1-9). During the construction of the main cooling reservoir (MCR) for STP 1 & 2, the water course of Little Robbins Slough within the STP site was relocated to a channel on the west side of the west embankment of the reservoir and rejoined its natural course about one mile east of the southwest corner of the MCR. Therefore, flooding in Little Robbins Slough has no adverse effects on STP 3 & 4.
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2.4S.1.2.1.3 Adjacent Drainage Basins To the west of the Colorado River in the coastal area is the Colorado-Lavaca River Basin, as shown on Figure 2.4S.1-10. This basin includes the Tres Palacios Creek, which is not tributary to either of those rivers. The Colorado-Lavaca River Basin drains into Tres Palacios Bay, north of Matagorda Bay. In the event of interbasin spillage, flood waters from the Colorado River Basin flow into Caney Creek near Wharton, as in the case of the 1913 flood, or into the San Bernard River Basin on the east edge of the Colorado River Basin (Reference 2.4S.1-10), or into the Colorado-Lavaca River Basin on the west.
2.4S.1.2.1.4 Shore Regions The STP 3 & 4 site is located 10.5 miles inland from Matagorda Bay and 16.9 miles inland from the Gulf of Mexico. It is approximately 75 miles from the Continental Shelf. The shoreline of Matagorda Peninsula along the Gulf of Mexico changes constantly, retreating landward or advancing seaward as the result of a combination of hydrologic and meteorological processes, climatic factors as well as engineering activities.
Matagorda Peninsula is a classic microtidal, wave-dominated coast with a mean diurnal tide range of approximately 2.1 ft. An evaluation of 20 years of data shows that “the mean significant wave height (Hs) at a location 40 km southeast of the Colorado River Entrance in 26 m water depth is 1.0 m, with a mean peak wave period (Tp) of 5.7 s. […] The hindcast data show that mean Hs varies from 0.8 m in August to 1.1 m from November through March and 1.2 m in April” (Reference 2.4S.1-11). This shore region is also greatly affected by waves generated by tropical storms and hurricanes.
The hydrologic features of the shore region are also altered by a series of engineering modifications. After the removal of a log jam on the Colorado River in 1929, a channel was dredged across the peninsula to allow the river to directly discharge to the Gulf of Mexico in 1936. Beginning in 1990s, the U.S. Army Corps of Engineers (USCOE) constructed jetties on each side of the river entrance and dredged an entrance channel. In 1993, USCOE constructed a diversion channel that directs the flow of the Colorado River into Matagorda Bay. The former river channel is now a navigation channel connected to the Intra Coastal Waterway (Reference 2.4S.1-11).
Studies conducted recently to calculate the average annual rate of shoreline changes show that the shoreline segment of Matagorda Peninsula 1.6 mile southwest of the Colorado River is retreating at a rate of 1.6 to 6.4 ft/yr. The shoreline from this point up north to the mouth of the Colorado River displays long-term advance. This is partly related to three factors: sediment load from the river, sand bypassing across the entrance jetties, and wave sheltering by the jetties. The shoreline northeast of the Colorado River is relatively stable and shows slight long-term advance in an area 8 miles to the northeast of the river mouth. (Reference 2.4S.1-11)
The historical hydrometeorological events were presented in Subsection 2.4S.5. Historical records show that about 33 hurricanes have impacted the Texas Coast from 1900 to 2005. A frequency analysis of hurricanes occurring between 1900 and 2005 along the Gulf Coast of Texas indicated that hurricanes can be expected to impact the
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STP 3 & 4 Final Safety Analysis Report
Texas Coast about once every three years. Based on the hydrometeorological conditions along the Texas Coast, Subsection 2.4S.5 develops the hydrometeorological design basis for considering potential hazards to the safety- related facilities due to the effects of probable maximum surge and seiche. The results show that the probable maximum surge and seiche flooding level should be 30.5 cm below site grade. Minimum grade for STP 3& 4 is defined as no less than 32 feet mean sea level.
2.4S.1.2.1.5 Surface Water Use Beginning January 5, 2002, 14 counties within the Lower Colorado River Basin, including Matagorda County where the STP site is located, were designated by Texas Water Development Board (TWDB) as the Lower Colorado Water Planning Region (LCWPR) for the purpose of regional water resource management. LCWPR is also known as Region K (Figure 2.4S.1-11). Sources of water supply in this region include 10 aquifer systems and 6 river and coastal basins. The Colorado River makes up the single largest source of surface water for this region with large volumes of water available from both run-of-river diversion rights and water stored in reservoirs. The total annual water supply in the LCWPR is estimated to be nearly 1.3 million acre-feet, of which over 73 percent is from surface water sources. (Reference 2.4S.1-12)
The Water Rights Database maintained by the Texas Commission on Environmental Quality (TCEQ) was used to identify surface water users whose intake could be adversely affected by the accidental release of contaminants from the STP site (Reference 2.4S.1-13). This database contains data for all active and inactive surface water right permits and water supply contracts. The active surface water users in Matagorda County are presented in Table 2.4S.1-4. The information includes the owner, water use types, annual water withdrawal amounts, surface water sources and corresponding river basins. As shown in the table, the major surface water user upstream of the STP site is the Lower Colorado River Authority (LCRA). The LCRA is one of the two entities designated by LCWPR as “wholesale water providers.” Together with the other wholesale water provider, city of Austin, they supply a significant amount of water for municipal and/or manufacturing use for the Lower Colorado Region. Because the major diversion points on the river by LCRA are located upstream of the STP site, surface water users served by LCRA are not likely to be affected by the accidental releases from the STP site. There are no known river water users downstream of the STP site.
The location of most of the surface water users given in Table 2.4S.1-4 is shown in Figure 2.4S.1-12. The users shown in this Figure are identified by the number given in the first column of Table 2.4S.1-4. Some of the users listed in Table 2.4S.1-4 are not shown in Figure 2.4S.1-12 because information on their location is not readily available. Also for some users the location shown in Figure 2.4S.1-12 is that of the actual water intake or water use, while for other users the location given is that of their mailing address. Figure 2.4S.1-12 shows the location of the STP 1 & 2 makeup water intake (point #4 in Figure 2.4S.1-12).
Hydrolflogic Description 2.4S.1-7 Rev. 12
STP 3 & 4 Final Safety Analysis Report
The plant water demands for STP Units 3 & 4 are located in Table 3.3-1 of the Environmental Report. The total surface water demand for STP Units 3 & 4 is given by Stream 3, Total Required River Water to MCR. The plant requires surface water consumption only for MCR makeup.
2.4S.1.2.1.6 Data Detailed descriptions of relevant spatial and temporal datasets in support of conclusions regarding safety of the plant are presented in corresponding subsections of this application. These datasets are all collected, maintained and distributed by Federal and State agencies. For example, the stream flow data of the Colorado River used in Subsection 2.4S.11 come from USGS; the water temperature records presented in Subsection 2.4S.7 are provided by LCRA; and the historical hydrometeorological data used in Subsection 2.4S.5 are from National Oceanic & Atmospheric Administration (NOAA).
2.4S.1.2.2 Groundwater The local and regional groundwater characteristics are described in Subsection 2.4S.12. A detailed list of current groundwater users, groundwater well locations, and the withdrawal rates in the vicinity of the STP 3 & 4 site is presented in Subsection 2.4S.12.2.
The plant water demands for STP Units 3 & 4 are located in Table 3.3-1 of the Environmental Report. The total ground (well) water demand for STP Units 3 & 4 is given by Stream 2, Plant Well Water Demand. The plant requires well water makeup for Power Plant Makeup/Use, UHS System Makeup, and Potable Water.
2.4S.1.3 References 2.4S.1-1 “STPEGS Updated Final Safety Analysis Report, Units 1 & 2,” Revision 13.
2.4S.1-2 “Report 04-6: Arc Hydro Developments for the Lower Colorado River Basin,” Daniel R. Obenour and Dr. David R. Maidment, Centers for Research In Water Resources Online, University of Texas at Austin, May 2004. Available at http://www.crwr.utexas.edu/online.shtml, accessed on April 24, 2007.
2.4S.1-3 “The 2005 Initially Prepared Regional Water Plans (for the 2006 Adopted Regional Water Plans) for Lower Colorado Planning Region (Region K),” Chapter 1, Texas Water Development Board (TWDB). Available at http://www.twdb.state.tx.us/rwpg/main-docs/IPP-index.htm, accessed on April 5, 2007.
2.4S.1-4 “Colorado River Flood Guide,” Lower Colorado River Authority (LCRA), Austin, TX, January 2003.
2.4S.1-5 “National Inventory of Dams,” U.S. Army Corps of Engineers. Available at http://crunch.tec.army.mil/nidpublic/webpages/nid.cfm, website accessed on April 11, 2007.
2.4S.1-8 Hydrolflogic Description Rev. 12
STP 3 & 4 Final Safety Analysis Report
2.4S.1-6 Website on dams, lakes and structures designed for flood management, water supply, hydroelectricity, Lower Colorado River Authority. Available at http://www.lcra.org/water/dams.html, website accessed on April 5, 2007.
2.4S.1-7 Website on managing the region’s water supply, Lower Colorado River Authority. Available at http://www.lcra.org/water/supply.html, accessed on May 15, 2007.
2.4S.1-8 “Water Resources Data, Texas, Water Year 2004,” Volume 4, Colorado River basin, Lavaca River basin, and intervening coastal basins, Long, Susan C. Aragon, Reece, Brian D., Eames, Deanna R., U.S. Geological Survey. Available at http://pubs.usgs.gov/wdr/2004/WDR-TX-04- 4/index.html, accessed on April 10, 2007.
2.4S.1-9 “Handbook of Texas Online, Under the World.” Available at http://www.tsha.utexas.edu/handbook/online/articles/LL/rhl8.html, accessed May 15, 2007.
2.4S.1-10 Friend of River San Bernard website, San Bernard River basin. Available at http://www.sanbernardriver.com/sanbernard/index.htm, accessed on June 27, 2007.
2.4S.1-11 “Texas Shoreline Change Project – Gulf of Mexico Shoreline Change from the Brazos River to Pass Cavallo,” James C. Gibeaut et al., Bureau of Economic Geology, The University of Texas, October 2000.
2.4S.1-12 Texas Water Development Board (TWDB) website, 2006 Adopted Regional Water Plans for Lower Colorado Planning Region (Region K). Available at http://www.twdb.state.tx.us/RWPG/main- docs/2006RWPindex.asp, accessed on April 15, 2007.
2.4S.1-13 Texas Commission on Environmental Quality, Water Rights Database and Related Files. Available at http://www.tceq.state.tx.us/permitting/water_supply/ water_rights/wr_databases. html, accessed on April 9, 2007.
2.4S.1-14 “Texas Administrative Code – Title 30, Part 1, Chapter 299,” Office of the Secretary of State of Texas, provisions adopted to be effective May 13, 1986 (11 TexReg 1978).
2.4S.1-15 River Basin Map of Texas, 1996, Bureau of Economy Geology, The University of Texas at Austin, Austin , Texas 78713-8924.
Hydrolflogic Description 2.4S.1-9 Rev. 12
STP 3 & 4 Final Safety Analysis Report degrees degrees Longitude Latitude -97.7867 30.295 -97.9067 30.3917 -99.6683 31.4967 -98.4183 30.7517 -100.515 31.895 -101.135 32.5833 -98.3383 30.555 -101.625 32.2183 -99.465 32.03 -96.7367 29.915 -99.3917 31.14 -100.9167 32.3183 -100.5333 31.3767 -100.86 32.2817 Authority District Water Authority District Water District Water Authority District Water Authority Type Name Owner Owner
Hazard County
Purposes
Dam Dam
Dam Type Dam
Completed
Year
Surface Area Surface
Drainage Area Drainage Maximum Storage Maximum acre-ft mi sq acre
3,223,000 38,1301,235,813 18,929 18.4 19421,087,530 REPGER 19,149 2,472 IH 1989982,000 32,660 H RECN 1962 50.1810,000 R RE Travis 23,060 4,140 H696,300 1937 ICR L 18,000 PGRE 1,511 H 1969448,200 Coleman IH Lower Colorado 3,854 River RE360,000 L 2.4 Green Tom H 1952 3,524 F227,000 R RE 7,300 Colorado River Municipal 7,820 Burnet 1933 37.8 H BR DOI 212,400 1952 R RE L207,265 RE 6,375 513 H Coke 1951 556 R91,680 River Colorado Lower 2,020 R REGreen L Tom 90,200 H 3,710 1963 F H 29988,628 1989 RE HR 164 Colorado River Municipal Brown RE 1,886 H SWF Engineers Of Corps Scurry 6.379,336 -100.4833 R 1,560 196673,100 L CP L 2,400 1959 RE 31.4667 Burnet 244 H70,700 H RE 1977 26,124 1 No WID County Brown 2,375 L Municipal River Colorado R RE 322 1,830 McCulloch -99.0017 1950 Howard R 1939 L H 1,610 31.8383 Lower Colorado River RE C CNPG L L 1949 Brady Of City Coleman H HR RE C Municipal River Colorado Mitchell H L H Fayette R U Travis Coleman City Of L L Coke TU Electric L River Colorado Lower L Mitchell Austin Of City U Sweetwater Of City Electric TU -100.2667 32.04 Maximum Height Maximum ft Table 2.4S.1-1 Major Dams in the Colorado River Basin River the Colorado Major Dams in 2.4S.1-1 Table 47 134 Draw Concho Rivers NID ID River TX01087 River Colorado 278 TX00989 Colorado River 146 TX04138 River Colorado 105 TX06386 River Colorado 148 TX00012 River Concho 128 TX01693 Creek Morgan 85 Dam Name (Marshall Ford Dam) (Colorado River Dam) River (Colorado (Stacy Dam) (Stacy Angelo Dam) (Morgan CreekDam) 1 Mansfield Dam 4 Buchanan Dam 11 Lake Salt Dam Natural TX06028 Springs Sulphur 14 Cedar Creek Dam TX04380 Cedar Creek 106 78 Lake Brownwood Dam TX02789 LakeB J Thomas Dam Pecan Bayou 120 16 MillerDam Tom TX01086 Colorado River 85 2 Simon Freese Dam 3 Buttes Twin 5 TX00022 Robert LeeDam South And Middle 6 OC FisherDam (San TX03517 Colorado River 140 9 Alvin Wirtz Dam10 Brady Dam TX00986 Colorado River12 118 Coleman Dam TX0165913 Champion Creek Dam Brady Creek TX01691 TX02152 104 Champion Creek15 Jim Ned Creek 120 OakCreek Dam 92 17 ColoradoDam City TX03516 Oak Creek 95
2.4S.1-10 Hydrolflogic Description Rev. 12
STP 3 & 4 Final Safety Analysis Report degrees degrees Longitude Latitude -97.5967 30.285 -98.385 30.73 -101.105 32.24 -101.7486 32.3217 -97.2917 30.155 -99.8683 31.9383 -99.88-99.975 31.1486 31.1683 -99.5967 31.1467 -100.0433 31.73 Authority District Water District Water Authority Type Name Owner Owner
Hazard County
Purposes
Dam Dam
Dam Type Dam
Completed
Year Surface Area Surface
560 1985 RE R H Runnels L City of Ballinger
Drainage Area Drainage Maximum Storage Maximum acre-ft mi sq acre
63,500 32,07650,241 803 15.349,290 193845,200 1,603 PG 4842,500 1991 9.3 HR REOT 510 3,83334,353 1,269 H T - 1948 1967 - RE S33,500 RE Burnet 193020,692 RE R L 65.5 Mitchell R 25816,962 H 643 L H R River Colorado Lower 970 8.7 198316,550 H Coleman Colorado River Municipal Travis RE 1993 F 244 38Green RE Tom L13,511 L R 1964 SWF Engineers Of Corps 449 RE -99.5667 T H 28.8 Austin Of City 13,042 Angelo San Of City 1970 31.85 S 76 RE R 21.8811,155 Runnels -100.4783 H 67 1962 Martin L C 31.3883 22.5 RE 1957 S L Bastrop - Winters of City RE C L Colorado River Municipal Callahan 1958 L C RE L Lower Colorado River L McCulloch C SWCD Divide Callahan L Concho -99.47 L McCulloch SWCD L 32.3133 Concho SWCD Concho L SWCD Concho Maximum Height Maximum ft 47 33 50 63 Table 2.4S.1-1 Major Dams in the Colorado River Basin (Continued) Colorado River Basin in the Dams Major 2.4S.1-1 Table River Draw Creek Pecan Bayou Pecan NID ID River TX06482 Springs Sulphur TX01626 Creek Fitzgerald 42 TX01625 Creek Brady 50 TX05952 Creek Valley 76 TX01677 Brady South TX02940 Prong North TX00988 Colorado River 96 Dam Name Dam Dam 28 Site Dam 31 Site Dam Dam) Moonen (Lake Dam 17 Site SCS Site 17 Dam Dam 17 Site SCS (Lake Clyde Dam) 18 Roy Inks Dam 22 Nasworthy Dam TX03139 South Concho 25 Sulphur Draw Springs 29 SCS WS Creek Brady 30 SCS WS Creek Brady 21 Decker Creek Dam TX0108923 Decker Creek Ballinger Municipal Lake 83 28 SCS WS Creek Brady 19 Mitchell County Dam20 TX06420 Hords Creek Dam Beals Creek TX00006 70 Hords Creek 91 24 Elm CreekDam TX0577626 Bastrop Dam Elm Creek27 WS Bayou Pecan Upper 57 TX02718 Creek Spicer 80
Hydrolflogic Description 2.4S.1-11 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.4S.1-1 Major Dams in the Colorado River Basin (Continued)
Notes:
Dam Type
(in the order
of importance) Dam Purposes Owner Type Downstream Hazard Potential
RE - Earth I - Irrigation F - Federal Potential hazard to the downstream area resulting from failure or misoperation of the dam or
ER - Rockfill H - Hydroelectric S - State facilities: L - Low S - Significant H - High PG - Gravity C - Flood Control L - Local and Storm Water Government Dams assigned the low Dams assigned the significant Dams assigned the high hazard Management hazard potential hazard potential classification are potential classification are those
CB - Buttress N - Navigation U - Public Utility classification are those those dams where failure or where failure or misoperation will where failure or misoperation results in no probably cause loss of human life. VA - Arch S - Water Supply P - Private misoperation results in no probable loss of human life but MV - Multi-Arch R - Recreation probable loss of human life can cause economic loss, CN - Concrete P - Fire and low economic and/or environment damage, disruption Protection, Stock, environmental losses. of lifeline facilities, or impact other Or Small Farm Losses are principally concerns. Significant hazard Pond limited to the owner’s potential classification dams are MS - Masonry F - Fish and property. often located in predominantly Wildlife Pond rural or agricultural areas but
ST - Stone D - Debris Control could be located in areas with
TC - Timber T - Tailings population and significant Crib infrastructure.
OT - Other O – Other
Hazard Potential Economic, Environmental,
Classification Loss of Human Life Lifeline Losses
Low None expected Low and generally limited to owner
Significant None expected Yes
High Probable. One or more expected Yes (but not necessary)
Source: Reference 2.4S.1-5
2.4S.1-12 Hydrolflogic Description Rev. 12
STP 3 & 4 Final Safety Analysis Report El. 1005.5 ft MSL El. 1005.5 ft El. 995.5 ft MSL MSL with 7 ft El. 995.5 El. 1020.5 ft MSL ft El. 1020.5 Buchanan Dam Buchanan on 1 & 2 (near north end and and center): north end on 1 & 2 (near Lower Colorado River Authority River Colorado Lower Colorado River, TX River, Colorado El. 1,020.35 ft MSL ft 1,020.35 El. 31,250 [1] 31,250 with 30 gates, each 33 ft x 15.5 ft x 15.5 33 ft each with 30 gates, Section(near 3 Powerhouse): the Multiple Concrete Arch, gated and gravity section gravity and Arch, gated Concrete Multiple Buchanan Lake 875,566 at El. 1,020.35 ft at El. 1,020.35 875,566 gates, each 40 ft xgates, 25.5 ft each 40 ft Section(far 4 north end): 145.5 10,987.6 El. 1,025.35 El. Varies, withmaximum the at 33.8ft Varies, 22,335 Secti 25, 199125, 1991 20, Dec. MSL on ft El. 1,021.4 General description General Hydraulics and Hydrology and Hydraulics El. 681 ft El. 681 Mansfield Dam Mansfield 38,130 [1] 38,130 1,131,650 at 1,131,650 Concrete gravityembankment with wing dams& saddle dikes El. 681 ft MSL El. 681 ft Lake Travis Lake Colorado River, TX River, Colorado Authority River Colorado Lower 278 7,089.4 El. 750 ft MSL 750 El. ft 30 El. 714 ft MSL El. 714 ft Table 2.4S.1-2 Pertinent Characteristics for Two Major Dams in the Colorado River the Colorado River Dams in Major Two for Pertinent Characteristics 2.4S.1-2 Table Characteristics Dam Type Crest Length (ft) Length Crest (ft) Width Top Spillway Elevation Spillway Historic High (ft) MSL on Dec. El. 710.4 ft Reservoir Watercourse Ownership Dimensions Height (ft) Structural Drainage Area (sq. mile) (sq. Area Drainage (acre) of Reservoir Area the Surface full when Elevation Dam of Top 18,622 (acre-feet) Storage Total
Hydrolflogic Description 2.4S.1-13 Rev. 12
STP 3 & 4 Final Safety Analysis Report Buchanan Dam Buchanan November to April: at or below El. 1,020.35 ft MSL ft El. 1,020.35 at to below April: or November 355,000 cfs 355,000 @ cfs each 19,000 floodgates 7 large @ cfs 7,250 each floodgates small 30 cfs each @ 1,500 3 turbines 14, 1951 9, Sep. 1952 MSL on ft El. 983.7 MSL MSL ft El. 1,018 at or below May to October: Hydraulics and Hydrology and Hydraulics Mansfield Dam Mansfield 24 floodgates @ 4,770 cfs each @ 4,770 floodgates 24 cfs each @ 2,200 3 turbines Table 2.4S.1-2 Pertinent Characteristics for Two Major Dams in the Colorado River (Continued) in the Colorado Major Dams for Two Characteristics Pertinent 2.4S.1-2 Table Characteristics [1] area non-contributory miles sq. 11,900 about Including Historic Low (ft)Historic (ft)Range Operating Normal (cfs) capacity Discharge below El. 681 ft or at Aug. MSL on ft El. 614.2 cfs 121,080 Source: Reference 2.4S.1-6 Reference Source:
2.4S.1-14 Hydrolflogic Description Rev. 12
STP 3 & 4 Final Safety Analysis Report (cfs) r year of r year 2004 Highest Lowest Mean Historical Annual Flow Rate Flow Rate Annual Historical Years of Years Record [2] Record Period of Period From Year From 1930 74 6,780 794 2,654 Area (square (square mile) [1] Drainage Drainage of record” is counted from the beginning year up to wate to the up year the beginning is from counted record” of .013 Bastrop 40,371 Table 2.4S.1-3 Streamflow Gauge Stations Downstream of Mansfield Dam of Mansfield Downstream Stations Gauge Streamflow 2.4S.1-3 Table mile) Longitude Latitude County (river (river Location Location 212.1 97.161 30 Name Gauge [2] active, currently “years and are listed in the table gauges All [1] All drainage areas include 11,403 square miles of probably noncontributing area noncontributing [1] probably of miles square 11,403 include areas drainage All Gauge No. 08158000 Austin08159200 Bastrop08159500 290.3 Smithville 236.608160400 LaGrange 97.69408161000 177 97.319 Columbus08162000 135.1 30.244 Wharton 30.10408162500 Travis 96.904 66.6 City Bay Bastrop 96.537 2.4S.1-8 Reference Source: 32.5 29.912 39,009 39,979 29.706 96.104 Fayette Colorado 96.012 1898 29.309 1960 40,874 41,640 28.974 Wharton Matagorda 1988 1916 42,003 106 42,240 44 1939 1948 16 88 7,535 9,073 590 65 828 56 9,913 10,810 2,168 2,227 653 930 11,120 14,270 3,100 2,662 615 375 2,740 2,628
Hydrolflogic Description 2.4S.1-15 Rev. 12
STP 3 & 4 Final Safety Analysis Report River/Stream Basin acre-ft Area Reservoir Capacity acres Use Type of Type Amount Amount acre-ft/yr Owner Type OrganizationOrganization 2,142,180 262,500 5 3 - 50,000 1,560 383 Colorado Colorado Colorado River River Colorado Table 2.4S.1-4 Active Surface Water Users in Matagorda County Matagorda Users in Water Surface Active 2.4S.1-4 Table Owner NameOwner or Site Name Water Division) Water Division) Water # Type WR WR Issue Date 1 62 63 6-28-19894 65 6-28-1989 Coast (Gulf Authority River Colorado Lower 66 67 6-28-1989 Coast (Gulf Authority River Colorado Lower 98 6-28-1989 19 1-20-1987 al et Agent Company Operating Nuclear STP 610 6-3-1988 Agent Company Operating Nuclear STP 6 Others11 4-25-2001 1Company Canal Farmers 12 2-7-1985 1 Organization Celanese Ltd13 1-20-1987 1Cornelius Herff 4-29-198514 6 102,000 4-29-1983 B Stanley O 15[1] 80,125 6 Partner Ltd Land Texas South 9-14-198216 al et Culwell A Don 1 2-7-1985 217 2 Schmermund John Organization 6 2-7-198518Lp Investments Land Minze The 6 4-29-198519 - 6 Matthes & Juanita Russell - 20,615 8-26-198820 Organization 6 Hudgins HD Of Division Hudgins 2-7-198521 al et Culwell A Don Organization 6 Individual 2-7-198522Llp Partnership Limited Family 3 Crouch 1 - 1,500 Organization 202,988 2-7-198523 Others 6 Individual Cross E Cattle Co. Inc. 3,222 2-7-198524 6 Individual Cross E Cattle Co. Inc. 2,400 Individual 15,000 1,000 4-4-198325 Organization Individual 6 3 Colorado Cross E Cattle Co. Inc. 2-7-198526 1 457.3 2,339 John A.Huebner Jr et 2 al 1-20-1987 1,500 Colorado27 728 6 1,500 Inc Farms Futuro 3 800 3 1-20-1987 60028 880 Others 1 I Savage Francis 12-23-198629 -& Wife J Peterson Lawrence 6 3 1-20-1987 Colorado-Lavaca Organization 2 40030 500 MaxCornelius Johnson 271 et al 3 1 3 2-22-1993 Inc. Organization Aquaculture Bay Matagorda 332 6 3 River Colorado 2-7-1985 481 Organization 75033 - F Harper Louis 668 - 1 404[2] 3 Others 6-24-1983 37534 River Colorado - 600 MatagordaDrainage Co Dist #1 1 400 1-20-1987 472al et Palacios Tres Colorado-Lavaca 592 Individual - 6 John A.Huebner Jr et al 2-16-1982 Organization Organization Ltd Company Pasture Runnels - 2 Others 79 3 Brazos-Colorado 3-5-1981 190 IndividualCompany Canal Farmers 550 - 6 3 Colorado 2-7-1985 Brazos-Colorado Moore C Linda 400 450 316 3 Organization - 334 G Zernicek Crk Lillian Moccasin Brazos-Colorado 400 300 411L Jones Vicki & Wayne Johnny 3 Colorado-Lavaca Brazos-Colorado Organization Colorado-Lavaca 260 296 Bayou Oak Live Individual - Others 3 3 Brazos-Colorado 2 Colorado 31 Slough Hardeman - Organization 219 500 3 3 - Colorado River 200 90 Crk Peyton - 301 8 Slough Buttermilk IndividualCrk Carancahua E Crk Caney 120 250 2 200 84.4 Colorado-Lavaca Brazos-Colorado Slough Oak Live Individual 3 - - 10 Individual Brazos-Colorado 50 3 Crk Blue 78 Brazos-Colorado - 400 3 3 150 90 - Brazos-Colorado 80 301 Slough Buttermilk Peyton Crk Brazos-Colorado 60 Colorado-Lavaca - - Peyton Crk Colorado-Lavaca 3 Colorado-Lavaca Peyton Crk - Brazos-Colorado 3 3 - - - Dry Crk Brazos-Colorado Palacios Crk Tres Boggy Big 90 Palacios Tres Brazos-Colorado 40 Palacios Tres Colorado-Lavaca Crk Peyton - 4.2 Colorado-Lavaca Brazos-Colorado - Cottonwood Crk Crk Caney Ducrow Brazos-Colorado Brazos-Colorado Palacios Tres Dry Crk Brazos-ColoradoCrk Caney Crk Caney Crk Boggy Big
2.4S.1-16 Hydrolflogic Description Rev. 12
STP 3 & 4 Final Safety Analysis Report River/Stream Colorado River Colorado Caney Crk Caney Caney Crk Caney Crk Caney Caney Crk Caney Caney Crk Caney Big Boggy Crk Boggy Big Caney Crk Caney Hardeman Slough Hardeman Caney Crk Caney Crk Caney Caney Crk Caney Cottonwood Crk Cottonwood River Colorado Cash's Buttermilk Slough Buttermilk CaneyCrk Basin Colorado Brazos-Colorado Brazos-Colorado Brazos-Colorado Brazos-Colorado Brazos-Colorado Brazos-Colorado Brazos-Colorado Brazos-Colorado Brazos-Colorado Colorado-Lavaca Colorado Brazos-Colorado Brazos-Colorado Brazos-Colorado Brazos-Colorado Colorado-Lavaca acre-ft ------82 Area Reservoir Capacity acres Use Type of Type 2 - 3 26 3 17 3 35 3 - 3 15 3 12.2 - 3 40.5 - 3 60 3 47.8 - 3 60 3 3 2 - 3 44.5 - 3 40 3 40 7 - Amount Amount acre-ft/yr 17 26 35 - 6 30 41 24 25 7 44 2 - Owner Type Use of the water right: 1 = Municipal/Domestic 2 = Industrial 3 = Irrigation 4 = Mining 5 = Hydroelectric 6 = Navigation 7 = Recreation 8 = Other 9 = Recharge = Domestic & Livestock Only11 13 = Storage Others Individual Individual Others Individual Others Organization - Estate or Trust Estate 20 Individual Individual Individual Individual Individual Individual Others Organization 40 Owner NameOwner or Site Name Table 2.4S.1-4 Active Surface Water Users in Matagorda County (Continued) County Matagorda Users in Water Surface Active 2.4S.1-4 Table Estate Of P J Reeves Jr J Reeves Of P Estate Johnny Wayne & Vicki L Jones Vicki & Wayne Johnny D R Alford Texas Brine Co Llc Co Brine Texas Michael D Stone D Michael Ben H Towler Jr Towler H Ben G P Hardy III P Hardy G Timothy R Blaylock & Wife Blaylock R Timothy Samantha Annette Hudgins Annette Samantha Donald R & Janice M Kopnicky M & Janice R Donald Michael J Pruett Michael John S Runnells III (Ashwood Farms) (Ashwood III S Runnells John # Type WR WR Issue Date 4344 6 6 2-7-1985 2-7-1985 4546 6 6 1-20-1987 2-7-1985 al et Hutson Glen Mrs 4748 649 6 1 2-7-1985 6-28-1989 6-5-1998 (HLP))Project Texas (South Lp Texas Nrg Organization - 42 6 2-7-1985 3940 641 6 1 2-7-1985 2-7-1985 6-20-1984 al et Holub Julia 5051 1 1 4-29-1985 4-4-1983 al et Culwell A Don 38 1 4-29-1983 al et Mcaferty Gene Betty 3536 637 6 6 2-7-1985 2-7-1985 2-7-1985 Source: Reference 2.4S.1-13 [1] This number the represents consumptive amount = 44 acre-feet[2] This = 360 capacity includes on-channel reservoiracre-feet, and capacity off-channel Right Type: Water 1 = Application/Permit 6 = Certificate of Adjudication 9 = Contract/Contractual Permit/Agreement
Hydrolflogic Description 2.4S.1-17 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Figure 2.4S.1-1 Site Map of the General Area of STP 3 & 4
2.4S.1-18 Hydrolflogic Description Rev. 12
STP 3 & 4 Final Safety Analysis Report
Figure 2.4S.1-2 Site Map of STP 3 & 4 (Topography based on USGS data)
Hydrolflogic Description 2.4S.1-19 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.4S.1-3 Existing (Pre-Development) Topography and Major Structures at STP 3 & 4 STP and Major Structures at Topography (Pre-Development) Existing 2.4S.1-3 Figure
2.4S.1-20 Hydrolflogic Description Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.4S.1-4 The Colorado River Basin (Reference 2.4S.1-2) Basin (Reference River The Colorado 2.4S.1-4 Figure
Hydrolflogic Description 2.4S.1-21 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.4S.1-5 Major Dams in the Colorado River Basin in the Dams Major 2.4S.1-5 Figure
2.4S.1-22 Hydrolflogic Description Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.4S.1-6 The Highland Lakes and Dams in the Lower Colorado River Basin (Reference 2.4S.1-6) River Basin (Reference Colorado in the Lower and Dams Lakes The Highland 2.4S.1-6 Figure
Hydrolflogic Description 2.4S.1-23 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Figure 2.4S.1-7 Area-Capacity Curves for Major Reservoirs on the Colorado River
2.4S.1-24 Hydrolflogic Description Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.4S.1-8 The Colorado River Streamflow Gauging Stations Downstream of Mansfield Dam of Mansfield Downstream Stations Gauging River Streamflow Colorado The 2.4S.1-8 Figure
Hydrolflogic Description 2.4S.1-25 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Figure 2.4S.1-9 Map of Flood Inundated Areas Near the STP 3 & 4
(Source: composite of Federal Emergency Management Agency maps 4854890375C, 4854890400C, 4854890550C, 4854890555D, 4854890560D, and 4854890565D)
2.4S.1-26 Hydrolflogic Description Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.4S.1-10 River Basins Adjacent to the Lower Colorado Basin (Reference 2.4S.1-15) (Reference to the Lower Colorado Basin Adjacent River Basins 2.4S.1-10 Figure
Hydrolflogic Description 2.4S.1-27 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.4S.1-11 Lower Colorado Water Planning Region (Region K) (Region Region Water Planning Colorado Lower Figure 2.4S.1-11
2.4S.1-28 Hydrolflogic Description Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.4S.1-12 Surface Water Users in Matagorda County (Reference 2.4S.1-13) (Reference County Users in Matagorda Surface Water 2.4S.1-12 Figure
Hydrolflogic Description 2.4S.1-29/30
Rev. 12
STP 3 & 4 Final Safety Analysis Report
2.4S.2 Floods The following site-specific supplement addresses COL License Information Item 2.14.
This section identifies historical flooding at the STP 3 & 4 site. It identifies and summarizes the individual types and combinations of flood-producing phenomena considered in establishing the flood design basis for safety-related plant features. The potential effects of local intense precipitation are also discussed in this section.
2.4S.2.1 Flood History The major natural events that may cause flooding near the STP 3 & 4 site are flooding from the Colorado River, hurricane-induced storm surges from the Gulf of Mexico, and local site flooding from Little Robbins Slough.
Little Robbins Slough is an ephemeral stream near the STP 3 & 4 site with its headwaters located approximately 2 mi northwest of the site. It has a total drainage area of approximately 4 sq. miles at the STP 3 & 4 site. Little Robbins Slough enters the STP site by crossing an irrigation canal of the Texas Gulf Coast Irrigation District through a siphon structure, as indicated on the United States Geological Survey (USGS) topographic map (Reference 2.4S.2-1). It passes under Highway FM 521 through pipe culverts. There are no stream gauge data or flood records available for Little Robbins Slough. The flood potential for Little Robbins Slough is discussed in connection with flood elevations from a local intense precipitation (also defined as the local probable maximum precipitation or local PMP) storm event in Subsection 2.4S.2.3.
The major historical hurricanes that affected the STP site are discussed in Subsection 2.4S.5. Table 2.4S.5-1 provides a chronological list of all major hurricanes that affected the Texas coast between 1900 and 2005. One of the most notable hurricanes that devastated the Texas Coast near the site is Hurricane Carla. This Category 4 hurricane (hurricane category in Saffir-Simpson Hurricane Scale) had landfall near Port O’Connor, Texas on September 11, 1961. It produced a peak surge elevation of approximately 20 ft MSL near the head of the Lavaca Bay (Reference 2.4S.2-2). North of the Gulf Inter Coastal Waterway and near the STP site, the peak surge elevation from Hurricane Carla was estimated to be about 16.5 ft MSL (Reference 2.4S.2-2).
The USGS maintains a network of stream gauging stations in the Colorado River basin. Three gauge stations, at Bay City (USGS gauge number 08162500), Wharton (08162000) and Columbus (08161000), are located closest to the site, as shown in Table 2.4S.1-3. As discussed in Subsection 2.4S.1, larger floodplain width downstream from the City of Columbus results in a large attenuation of flood peaks downstream from the Columbus gauge. Consequently, stream gauging data from Bay City and Wharton are more representative of the streamflow conditions near the STP 3 & 4 site. The USGS gauge station at Bay City is located approximately 16 mi upstream from the site. The gauge at Wharton is located further upstream, approximately 50 mi from the site. Because the watershed boundary downstream of Wharton is very narrow, the contributing river basin drainage areas for the two stations
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are very similar in size (Table 2.4S.1-3). The locations of the gauge stations are shown in Figure 2.4S.1-8.
Annual peak streamflow data at Bay City are available for the water years 1940 and from 1948 to 2006 (Reference 2.4S.2-3). A water year starts on October 1 of the preceding year and ends on September 30 of the current year. For example, the water year 1940 ranged from October 1, 1939 to September 30, 1940. At Wharton the period of records ranges between water years 1919 and 2006 (Reference 2.4S.2-4). Annual peak streamflow data for the period of record for the two stations are presented in Tables 2.4S.2-1 and 2.4S.2-2, respectively. The variations of annual peak stream flow are also shown in Figure 2.4S.2-1 and Figure 2.4S.2-2. The two gauge stations are located below the series of dams on the Colorado River, which are discussed in Subsection 2.4S.1 and shown in Figure 2.4S.1-5. Of the dams and reservoirs in the lower Colorado River basin, Mansfield Dam along with Lake Travis is the most downstream dam that provides the maximum floodwater storage and management. The Mansfield Dam was constructed in 1942. For the water years ranging from 1942 to 2006, the highest observed peak streamflow in the Lower Colorado River at Bay City was 84,100 cfs on June 26, 1960. At Wharton the observed peak streamflow for the same period was 74,800 cfs recorded on October 23, 1960. The historic peak at Wharton was recorded on June 20, 1935, with a peak streamflow of 159,000 cfs (Reference 2.4S.2-4).
The ten highest recorded flood elevations at Bay City are shown in Table 2.4S.2-3 (References 2.4S.2-5 and 2.4S.2-6). Although reported by the USGS, the flood levels before 1948 were recorded by others. The historical highest flood levels at Bay City were due to flooding in the uncontrolled basin of the Colorado River (elevation 56.1 ft MSL in 1913, 55.4 ft MSL in 1922, 55.0 ft MSL in 1929 etc., as shown in Table 2.4S.2- 3). After the construction of the dams, the highest flood levels observed in the Lower Colorado River at Bay City were 46.4 ft MSL and 38.67 ft MSL in the 1960 and 1995 water years, respectively.
Flood elevations near the STP 3 & 4 site are available from published studies. Halff Associates Inc. (Reference 2.4S.2-7) studied the flood hydrology of the Lower Colorado River as part of the Colorado River Flood Damage Evaluation Project – Phase I for the U.S. Army Corps of Engineers and the Lower Colorado River Authority. For the October 1998 flood event, which represents one of the highest recorded flow rates on the Lower Colorado River, with a peak flow of 81,800 cfs at the Bay City gauge, Halff Associates Inc. computed a water surface elevation of approximately 21.0 ft MSL upstream of Highway FM 521 bridge crossing. The bridge crossing is located east of the STP site.
The USGS recently established a water surface elevation gauge station on the Colorado River Bypass Channel near Matagorda (08162506), approximately 10 mi south of the STP 3 & 4 site. The gauge station has data records from October 1999 to May 2007. A maximum recorded water surface elevation of 7.05 ft MSL was observed at this station (on the East Colorado River) on November 27, 2004 (Reference 2.4S.2- 8). The streamflow magnitude for this day was approximately 72,900 cfs at the Bay City gauge on the Colorado River (Reference 2.4S.2-3).
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There are no records of ice sheet formation or ice jam events on the Colorado River or Little Robbins Slough, as discussed in Subsection 2.4S.7. Also, there are no records of any landslide (submarine or subaerial) or distant tsunami source-induced flooding events at the STP 3 & 4 site. Historical tsunami events are discussed in Subsection 2.4S.6.
2.4S.2.2 Flood Design Considerations The design basis flooding (DBF) elevation for the STP 3 & 4 site is determined by considering a number of different flooding scenarios. The potential flooding scenarios applicable and investigated for the site include the following: probable maximum flood (PMF) on streams and rivers, potential dam failures, probable maximum surge and seiche flooding, probable maximum tsunami, flooding due to ice effects, and potential flooding caused by channel diversions. In applicable cases, the flooding scenarios were investigated in conjunction with other flooding and meteorological events, such as wind generated waves and tidal levels, as recommended in the guidelines presented in ANSI/ANS 2.8-1992 (Reference 2.4S.2-9). Detailed discussions on each of these flooding events and how they were estimated are found in Subsections 2.4S.3 through 2.4S.7, and Subsection 2.4S.9.
The estimation of the PMF water level on the Colorado River is discussed in Subsection 2.4S.3. Three different combinations of parameters including PMP storm events and antecedent water levels, contributing catchment areas, upstream reservoir releases, and base flow conditions are considered in estimating the PMF streamflow magnitude. The maximum PMF water level for the Colorado River at the STP 3 & 4 site has been determined to be at elevation 26.3 ft MSL. Because the site grade for the STP 3 & 4 power block and the ultimate heat sink (UHS) areas are located above elevation 32 ft MSL the PMF elevation would not cause a flooding risk to any of the safety-related systems, structures and components (SSCs).
The impacts of postulated dam failures on the STP 3 & 4 safety-related SSCs are discussed in Subsection 2.4S.4. Two aspects of flooding are considered. First, flood elevation at the site is investigated as a result of cascading failure of dams in the Colorado River basin and its tributaries upstream of the site. The resulting water level at the site, including coincidental wind set-up and wave run-up is 34.4 ft MSL. Second, the flood elevation at the site is investigated due to the failure of the Main Cooling Reservoir (MCR) embankment. A maximum flood elevation of 38.8 ft MSL was determined at the STP 3 & 4 site as a result of the MCR embankment breach. Based on this, the DBF is conservatively established as 40.0 ft MSL. The MCR embankment breach flood level is above the site grade and the ground floor elevation of the safety- related SSCs in the power block area. Therefore, all power block safety-related structures will require appropriate flood protection measures below elevation 40.0 ft MSL, such as water tight doors and components that will prevent any flooding of the safety-related SSCs. The UHS and reactor service water (RSW) pump house is contiguous with the UHS basin. The UHS basin and RSW pump house are water tight below elevation 50 ft MSL. Flooding of these structures due to DBF is therefore precluded. Flood protection requirements are discussed in Subsection 2.4S.10.
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Probable maximum surge and seiche flooding as a result of the probable maximum hurricane (PMH) in the Gulf of Mexico is presented in Subsection 2.4S.5. The probable maximum storm surge (PMSS) water level at the STP 3 & 4 site is estimated to be elevation 31.1 ft MSL. This elevation is lower than the flood elevation at the site due to the postulated breach of the MCR embankment and cascading failures of dams in the Colorado River. The PMSS flood elevation is also lower than all entrance elevations of safety-related SSCs at the STP 3 & 4 site.
Subsection 2.4S.6 describes the estimation of the probable maximum tsunami (PMT) water level. The maximum water level associated with a PMT at the STP 3 & 4 site is 11.5 ft MSL. Therefore, the PMT would not be a flood risk to the STP 3 & 4 site. As discussed in Subsections 2.4S.7 and 2.4S.9, it is unlikely that ice effect and channel diversions, respectively, would pose any flood risk to the STP 3 & 4 site.
The maximum water level due to a local PMP storm event is estimated and discussed in Subsection 2.4S.2.3. The maximum water level in the power block area due to a local PMP storm event is estimated to be at elevation 36.6 ft MSL. The maximum flood elevation due to the local PMP storm event is also above the ground floor elevations for the safety-related SSCs in the power block area. However, this elevation is lower than the flood elevation due to the postulated breach of the MCR embankment or cascading failures of dams in the Colorado River. Flood protection measures adopted for the DBF would adequately provide the required protection to the safety-related SSCs against flooding due to a local PMP storm event.
2.4S.2.3 Effects of Local Intense Precipitation The effects of local intense precipitation (or local PMP) in the vicinity of the STP 3 & 4 site are discussed in this subsection. The site drainage system used in the analysis of flooding due to a local PMP storm is conceptualized such that it would facilitate drainage away from the plant safety-related SSCs during non-PMP flood events.
2.4S.2.3.1 Probable Maximum Precipitation Depths The design basis for the local intense precipitation is the all season one sq. mile or point PMP as obtained from the U.S. National Weather Service (NWS) Hydro- meteorological Reports No. 51 and 52 (HMR-51 and HMR-52) (References 2.4S.2-10 and 2.4S.2-11). Table 2.4S.2-4 presents the one sq. mile PMP depths for various durations at the STP 3 & 4 site with the 5-minute and 1-hour one sq. mile PMP depths estimated to be 6.4 in. and 19.8 in., respectively. The 5-min and 1-hour local PMP depths on one sq. mile exceed the corresponding maximum rainfall rates of 6.2 in. (15.7 cm) and 19.4 in. (49.3 cm), respectively, specified in the reference ABWR DCD Tier 1 Table 5.0, and Tier 2 Table 2.0-1 (see STP DEP T1 5.0-1). Justification for the departure specific to the STP 3 & 4 site is further discussed in Table 2.0-2. The estimated rainfall depths presented in HMR-51 are for precipitation duration ranging from 6 hrs to 72 hrs, and for drainage areas from 10 sq. miles to 20,000 sq. miles. Based on these rainfall depths, HMR-52 provides a procedure for estimating short duration point (or one sq. mile) PMP depths for up to 1 hr rainfall duration. PMP rainfall depths for duration between 1 hr and 6 hrs are obtained by logarithmic fit of rainfall depths available for different storm durations. Figure 2.4S.2-3 is a plot of the PMP
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depths against corresponding storm durations, as obtained from HMR-51 and HMR- 52. The PMP depths for 2 hrs and 3 hrs durations are also shown on the figure.
2.4S.2.3.2 Local Drainage Components and Subbasins The STP 3 & 4 site is located northwest of the STP 1 & 2 site adjacent to the plant access road from the north. The proposed site layout and drainage system are shown in Figure 2.4S.2-4. The site grade in the immediate vicinity of the STP 3 & 4 power block area ranges from an elevation of about 30 ft MSL to 36.6 ft MSL, with generally higher elevation on the northern side. The center of the power block area has the highest grade elevation of about 36.6 ft MSL, which slopes down towards the corners with a 0.4% gradient. The corners of the power block area are at an elevation of approximately 32 ft MSL.
The STP 3 & 4 power block and UHSs areas are contained within a security perimeter. Drainage from the area within the security perimeter is collected in two drainage channels labeled the East and West Channels, running north-south that drain to an east-west running Main Drainage Channel (MDC) north of the power block area and outside the security perimeter (Figure 2.4S.2-4). The security perimeter includes personnel security fences at grade elevation and a concrete vehicular barrier outside the security fences. Drainage across the security barrier is permitted through narrow, grated openings in the concrete vehicular barrier and underground culverts in the security fences at the drainage ditches. For purposes of the local PMP analysis the openings in the vehicular barrier and the culverts are conservatively assumed to be blocked. Consequently, during a PMP storm event drainage from within the area enclosed by the security perimeter would likely take place by overtopping of the concrete barrier.
The East Channel is located within the security perimeter along the north access road (Figure 2.4S.2-4). Drainage from the STP 3 power block area and UHS is collected at catch basins and diverted to the East Channel by connecting drainage pipes. Similarly, for the STP 4 power block area, and UHS drainage collected at catch basins is diverted by pipes to the West Channel (Figure 2.4S.2-4). During a PMP storm event all catch basins and pipe flows are assumed inoperative; consequently, surface runoff from the power block area would be collected in the drainage channels as overflows. Runoff from building roofs is conservatively assumed to contribute to surface runoff without any delay. Roof runoff is also collected by the East and West Channels.
Outside the security perimeter, drainage from the STP 1 & 2 switchyard, located east of the north access road, is directed towards the main drainage channel. West of the security perimeter, drainage from the area within the west access road (Figure 2.4S.2- 4) and the Main Drainage Channel are collected by a small channel that flows north towards the Main Drainage Channel.
Apart from the drainage from the area within the security perimeter, the Main Drainage Channel also collects runoff from a portion of the area bounded by Highway FM 521. The Main Drainage Channel first runs westward parallel to the security barrier north of the STP 3 & 4 power block area, turns southwestward near the northwest corner of the security barrier, runs south parallel to the west MCR embankment, and finally drains to
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Little Robbins Slough south of the MCR. Prior to crossing the West Access Road the Main Drainage Channel also joins with Little Robbins Slough at a second location by a link channel (Figure 2.4S.2-4). Approximately 500 ft south of the link channel junction, both the Main Drainage Channel and Little Robbins Slough cross under the West Access Road through pipe culverts.
Considerable area north of Highway FM 521 contributes to Little Robbins Slough, as shown in Figure 2.4S.2-5. Runoff from this area crosses Highway FM 521 also through pipe culverts. In the event of a PMP storm it is likely that Highway FM 521 would be overtopped and runoff from this area would contribute to the flow in Little Robbins Slough.
For the analysis of local PMP flooding, the STP 3 & 4 site drainage area has been divided into seven subbasins based on USGS topographic maps, site aerial survey, and the location of roads and barriers. These subbasins, North1, North2, North3, PBN1, PBW1, PBW and PBE, are shown in Figure 2.4S.2-5. Contributing drainage areas for each of the subbasins are presented in Table 2.4S.2-5. Runoff from these subbasins provides the peak discharges entering the East and West Channels, the Main Drainage Channel, and Little Robbins Slough (Figure 2.4S.2-4).
2.4S.2.3.3 Peak Discharges The U.S. Army Corps of Engineers computer program HEC-HMS (Reference 2.4S.2-12) was used to develop the hydrologic model and determine peak discharges in the drainage basins. The land surface cover for the STP 3 & 4 subbasins consists primarily of developed impervious areas, fallow land, irrigated land, and small grass surfaces. Within the catchment areas south of Highway FM 521, Laewest series (LaA) soil is present, which consists of very deep, moderately well drained, very slowly permeable, clayey soils on uplands. These soils are formed in calcareous, clayey marine sediments (Reference 2.4S.2-13). North of FM 521, in addition to LaA soil series, loamy Dacosta (DaA) and Edna (EdA) soil series are also present in the irrigated areas. These soils are also very slowly permeable and moderately drained. All these soil series fall in hydrologic soil group ‘D’. To estimate peak discharges from a PMP storm event, however, all surfaces are conservatively assumed to be impervious to reflect a saturated ground condition prior to the start of the PMP storm event.
The times of concentration (tc) for the subbasins are estimated using the methodologies suggested by the U.S. Natural Resources Conservation Service (NRCS), as given in TR-55 Manual (Reference 2.4S.2-14). To account for non- linearity effects during extreme flood conditions, the computed tc were reduced by 25% in accordance with guidance from the U.S. Army Corps of Engineers Engineering Manual EM-1110-2-1417 (Reference 2.4S.2-15). The lag times are estimated as 60% of tc (Reference 2.4S.2-16).
Runoff from the subbasins North1 and North2 contributes to Little Robbins Slough after crossing Highway FM 521 through pipe culverts. It is assumed that during a local PMP storm event runoff would accumulate upstream of FM 521 in addition to the flow through the culverts to Little Robbins Slough. When the upstream storage elevation
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exceeds the crest elevation of FM 521, overtopping of FM 521 would contribute additional flow to Little Robbins Slough. Because the culverts are located upstream of the site, allowing these culverts to flow into the basin increases the local PMP discharges to the site. Thus, the culverts were assumed to be open, rather than blocked, as a conservative modeling approach for the STP 3 & 4 site.
The subbasin areas, local PMP intensities, and lag times were input to the HEC-HMS computer model. A runoff curve number of 98, representing impervious surfaces (Reference 2.4S.2-14), is used in the model for the entire drainage area. The NRCS dimensionless unit hydrograph option in HEC-HMS was utilized for the developments of the peak discharges from the various subbasins. A storm duration of 6 hrs was specified along with 5 min duration for incremental rainfall intensities.
A schematic of the HEC-HMS model is given in Figure 2.4S.2-6, and resulting peak discharges along with the time of peak for different subbasins are presented in Table 2.4S.2-6. Although the subbasin PBN1 drains to the Main Drainage Channel over its length, in the HEC-HMS model the drainage is directed towards the drainage element OutFlow as shown in Figure 2.4S.2-6. Distribution of flow from PBN1 to the Main Drainage Channel is accounted for in the hydraulic model developed for the system to compute the PMP flood elevation. The hydraulic model is discussed in Sub-section 2.4S.2.3.4. Table 2.4S.2-6 shows that because of longer lag times, upstream storage and overflow of Highway FM 521, the combined peak discharge from the subbasins North1 and North2 occur at hour 6:25 at the upstream boundary of Little Robbins Slough (LRS, see Figure 2.4S.2-6 for drainage elements). As a result, the flood peak in Little Robbins Slough at the confluence with the Main Drainage Channel occurs much later than the combined flood peak discharge in the Main Drainage Channel (MDC4 in Figure 2.4S.2-6) and the subbasin PBN1. Therefore, the combined peak discharge from the Main Drainage Channel and PBN1 is the largest contributor to the peak discharge from the entire local PMP basin (OutFlow in Figure 2.4S.2-6), even though the combined peak discharge from Little Robbins Slough (LRS) and North3 is of comparable magnitude to the peak discharge from the entire basin. This also indicates that flooding in Little Robbins Slough alone would not produce a flood magnitude at the STP 3 & 4 site that is higher than the flood magnitude produced by the local PMP flood event from the site.
2.4S.2.3.4 Hydraulic Model Setup The computer program HEC-RAS, also developed by the U.S. Army Corps of Engineers (Reference 2.4S.2-17), was used to estimate the peak local PMP water levels in the power block area. Cross sections for the drainage channels included in the model were developed at locations shown in Figure 2.4S.2-7. The Main Drainage Channel has a bottom width of 30 ft and a longitudinal gradient of 0.061 percent. The bottom elevation at cross section 5280 (Figure 2.4S.2-7) was 24 ft MSL. In the HEC- RAS model this cross section was also used unchanged at the upstream cross section 5380. Both the East and West Channels have a bottom width of 10 ft with longitudinal gradients of 0.298 percent and 0.756 percent, respectively. The bottom elevation of the upstream cross sections (cross section 1690 in Figure 2.4S.2-7) of both the channels was 29 ft MSL. The Main Drainage Channel and the East and West
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Channels all have a horizontal (H) to vertical (V) side slope of 3:1 (H:V). Little Robbins Slough is a natural stream for which the cross sections were obtained from aerial survey data. Figure 2.4S.2-7 shows very wide floodplain areas associated with several channels. The floodplain areas likely provide storage volume and contribute to channel conveyance when floodwater rises above the floodplain. These were modeled with a high surface roughness coefficient, as discussed later in this sub- section. The cross section data were input into the HEC-RAS model. The two downstream cross sections on Little Robbins Slough intersect the adjacent cross sections on the Main Drainage Channel. This was allowed in the model to avoid a sudden change in cross sectional properties from the immediate upstream cross sections, in addition to defining a portion of the upstream cross sections as ineffective flow area in the HEC-RAS model. The area of overlap was approximately 1 percent of the area of subbasin North3. Because the water surface elevation at the junction of Little Robbins Slough with the Main Drainage Channel is governed by the water surface elevation in the Main Drainage Channel, the overlap in cross section would have insignificant impact on the model results.
The inflow discharges were also input into the HEC-RAS model. The discharges were estimated from the HEC-HMS discharge hydrographs. Table 2.4S.2-6 indicates that subbasin peak discharges do not occur at the same time. The peak discharge at the downstream outflow location (OutFlow) occurs within 25 min of the peak discharges for subbasins PBE, PBW, PBN1, and PBW1. The peak discharge in Little Robbins slough (LRS) occurs much later than those for the subbasins. To determine the maximum water surface elevation within the power block area, it is therefore conservatively assumed that the peak discharges for subbasins PBE, PBW, PBN1, and PBW1 occur simultaneously with the outflow peak. For subbasin North3 and branch LRS the flow discharges corresponding to the time of peak outflow discharge (hour 3:35) were used to develop the inflow discharge for the HEC-RAS model. Because the peak discharges in the subbasins near the power block area are assumed to occur simultaneously, the total discharge at the outflow location in the HEC-RAS model is greater than the corresponding total peak discharge obtained from the HEC-HMS model.
The peak discharge obtained for a subbasin in HEC-HMS was first distributed to the most upstream cross section of a stream reach in HEC-RAS in proportion to the area contributing to that cross section and the total area of the subbasin. The remaining portion of the peak discharge is then distributed equally among the remaining cross sections within the receiving channel reach. For example, subbasin PBE has a total area of approximately 0.089 sq. miles that contributes a peak flow of 1443.3 cfs (Table 2.4S.2-6) to the East Channel. The most upstream cross section of the East Channel receives flow from approximately 0.039 sq. miles area. Therefore, a peak flow of (0.039/0.089 × 1443.3 =) 632.5 cfs was assigned at the upstream cross section. The remaining flow was divided equally between the remaining cross sections and added to the upstream peak flow. The same approach was also adopted for the West Channel. Peak flow from the subbasin PBN1 was distributed similarly over the Main Drainage Channel. For the Main Drainage Channel, two segments of the channel reach were considered in distributing the peak flow discharge based on uniformity in cross section extent and areas associated with the uniform cross section channel reach. Additionally, peak flow from subbasin PBW1 was added to the Main Drainage
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Channel as a point inflow at a location where a small stream drains the runoff from this subbasin. The outflow from USLRS (Figure 2.4S.2-6) was used as inflow at the upstream cross section on Little Robbins slough, whereas runoff from the subbasin North3 was distributed equally over the cross sections of Little Robbins Slough. Downstream of a junction, the combined flow from the channels upstream of the junction was specified in addition to any fraction of peak discharge at the cross section.
The total discharge to the channels is assumed to remain within the model basin and drains through the downstream boundary on the Main Drainage Channel at the West Access Road crossing. Consequently overflow from the model area to adjacent drainage areas to the west, east, and southeast is not allowed for a local PMP storm event. Because additional subbasin discharge from the area outside Highway FM 521 contributes to the total flow in the model, the resulting water surface elevation within the model domain would be conservative.
The vehicular security barrier surrounding the plant area (Figure 2.4S.2-4) was modeled as a vertical wall on three sides (east, west, and south) of the power block area. Where the security barrier crosses the East and West Channels north of the STP 3 & 4 power block area, in-line weirs were used to model the extent and flow over the barrier. As water level inside the security perimeter exceeds the top elevation of the barrier, flow would begin to spill over the barrier depending on the water level in the Main Drainage Channel at the channel junction. The antecedent water level within the security perimeter to pass the peak flow from the East and West Channels was assumed to be the same as the height of the security barrier. The combined flow from the Main Drainage Channel and Little Robbins Slough discharges to the area south of the West Access Road through pipe culverts. Because the pipe culverts were assumed to be blocked, outflow would take place only by overtopping of the road, which was also modeled as an in-line weir structure in HEC-RAS. The width and breadth of the in-line structure were obtained from the aerial survey data for the West Access Road in this area. A broad-crested weir coefficient of 2.6 was assumed for all the inline structures.
Flow interactions at the junctions were analyzed with the energy junction equation option in HEC-RAS. Depending on the surface cover of the drainage channels and floodplains, various Manning’s n values were used in the model as recommended in Reference 2.4S.2-18. In the power block area, the East and West Channels have a gravel bottom with sides of dry rubble or riprap. An n value of 0.036 is used for these channels. The main drainage channel consists of straight reach sodded earthen banks for which a Manning’s n value of 0.033 is used. Little Robbins Slough is an excavated earthen bank winding and sluggish stream with short grasses. An n value of 0.033 is also recommended for such streams. For the floodplains, a Manning’s n value of 0.07 is conservatively assumed for those of the East and West Channels that represents a surface with heavy weeds. For all other floodplains a Manning’s n of 0.16 was used considering that the floodplains consist of medium to heavy brush on the surface.
The HEC-RAS model simulation was performed for a steady state sub-critical flow condition for which only the downstream boundary condition is required on the Main Drainage Channel. A sensitivity analysis of model results indicated that the flow over
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the weir structure at the West Access Road crossing would be controlled by an upstream flow condition when the downstream boundary water level is below approximately elevation 34 ft MSL. Considering that a large portion of the flow is intercepted upstream of the West Access Road, it is very unlikely that the water surface elevation downstream of the West Access Road would be above 34 ft MSL. Consequently a downstream boundary with constant water level at 34 ft MSL is selected for the simulation of local PMP flood elevations.
2.4S.2.3.5 Flood Elevations The HEC-RAS computer model simulation was used to estimate the maximum water surface elevation within the STP 3 & 4 power block area. Model simulation results showed that the maximum water surface elevation within the power block area was elevation 36.6 ft MSL. This elevation is conservatively assumed to affect the entire power block area of STP 3 & 4. This flooding elevation is higher than the power block grade elevation and the ground floor slab elevation of the safety-related SSCs. However, the local PMP water surface elevation is less than the flood elevation estimated from the postulated breach of the MCR embankment, which was estimated to be at elevation 38.8 ft MSL, as discussed in Subsection 2.4S.4. Flood protection measures for the safety-related SSCs against flooding due to the MCR embankment breach are sufficient to provide protection against flood elevation due to the local PMP storm event.
Runoff from roofs of structures in the power block area would contribute to flows in the East and West Channels. Because the power block area would be inundated during a local PMP storm event, flooding of the safety-related SSCs due to sheet flow from roof and surface runoff is not relevant.
The RSW pump house is contiguous with the UHS basin. The lowest elevation associated with the entrances or openings of these safety-related structures is the RSW pump house slab elevation that is at 50 ft MSL, below which the UHS is water tight. Flooding of these structures due to a local PMP storm event is therefore precluded.
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2.4S.2.4 References 2.4S.2-1 “Blessings SE Quadrangle, Texas-Matagorda Co., 7.5 Minute Series (Topographic) Map,” United States Geological Survey, 1995.
2.4S.2-2 “Verification Study of a Bathystrophic Storm Surge Model,” G.P.- Carayannis, Technical Memorandum No. 50, Coastal Engineering Research Center, U.S. Army Corps of Engineers, May 1975.
2.4S.2-3 “Peak Streamflow for Texas, USGS 08162500 Colorado River near Bay City, TX,” United States Geological Survey, National Water Information System. Available at http://nwis.waterdata.usgs.gov/tx/nwis/peak?site_no= 08162500&agency_cd=USGS&format=html, accessed April 27, 2007.
2.4S.2-4 “Peak Streamflow for Texas, USGS 08162000 Colorado River at Wharton, TX,” United States Geological Survey, National Water Information System. Available at http://nwis.waterdata.usgs.gov/tx/nwis/peak?site_no=08162000&agency_ cd=USGS&format=html, accessed April 27, 2007.
2.4S.2-5 “Colorado River 3 SW Bay City,” National Weather Service, Advanced Hydrologic Prediction Service, Weather Forecast Office Houston/Galveston, TX, West Gulf River Forecast Center. Available at http://ahps.srh.noaa.gov/ahps2/hydrograph.php?wfo=hgx&gage=bact2&ty pe=0&view=1,1,1,1,1,1, accessed June 3, 2007.
2.4S.2-6 “Water Data Report TX-2005, 08162500 Colorado River near Bay City, TX,” The United States Geological Survey, Texas, 2006.
2.4S.2-7 “Colorado River Flood Damage Evaluation Project, Final Report, Phase I, Volume I and Volume II,” prepared for the Lower Colorado River Authority and Fort Worth District Corps of Engineers, Halff Associates, Inc., July 2002.
2.4S.2-8 “USGS 08162506 Colorado River Bypass Channel Near Matagorda, TX,” United States Geological Survey, National Water Information System. Available at http://waterdata.usgs.gov/tx/nwis/nwisman/?site_no=08162506&agency_c d=USGS, accessed June 3, 2007.
2.4S.2-9 “Determining Design Basis Flooding at Power Reactor Sites,” ANSI/ANS- 2.8-1992, Historical Technical Reference, American Nuclear Society, July 1992.
2.4S.2-10 “U.S. Department of Commerce National Oceanic and Atmospheric Administration (NOAA), Probable Maximum Precipitation Estimates, United States East of the 105th Meridian,” Hydrometeorological Report No. 51, NOAA, June 1978.
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2.4S.2-11 “U.S. Department of Commerce National Oceanic and Atmospheric Administration, Application of Probable Maximum Precipitation Estimates - United States East of the 105th Meridian,” Hydrometeorological Report No. 52, NOAA, August 1982.
2.4S.2-12 “HEC-HMS, Hydrologic Modeling System, Version 3.0.1,” U.S. Army Corps of Engineers, Hydrologic Engineering Center, April 2006.
2.4S.2-13 “Soil Survey of Matagorda County, Texas,” U.S. Department of Agriculture, Natural Resources Conservation Service (In Cooperation with Texas Agricultural Experiment Station), 2001.
2.4S.2-14 “Urban Hydrology for Small Watersheds, Technical Release 55,” U.S. Department of Agriculture, Soil Conservation Service (now known as Natural Resources Conservation Service), June 1986.
2.4S.2-15 “EM 1110-2-1417 Flood-Runoff Analysis,” U.S. Army Corps of Engineers, August 1994.
2.4S.2-16 “HEC-HMS, Hydrologic Modeling System, Technical Reference Manual,” U.S. Army Corps of Engineers, Hydrologic Engineering Center, March 2000.
2.4S.2-17 “HEC-RAS, River Analysis System, Version 3.1.3”, U.S. Army Corps of Engineers, Hydrologic Engineering Center, May 2005.
2.4S.2-18 “Open-Channel Hydraulics,” Chow, Ven Te, 1959.
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Table 2.4S.2-1 Peak Streamflow in the Lower Colorado River at Bay City (USGS Gauge No. 08162500) Gauge Height [1] Streamflow [2] Water Year Date (ft) (cfs) 1940 July 4, 1940 46.6 83,300 1948 May 28, 1948 No data 6,390 1949 April 28, 1949 34 36,000 1950 June 4, 1950 30.51 24,800 1951 June 7, 1951 25.75 12,000 1952 May 29, 1952 29.07 20,100 1953 May 1, 1953 30 23,300 1954 December 5, 1953 24.83 10,000 1955 May 21, 1955 25.74 11,900 1956 October 10, 1955 20.95 4,460 1957 May 1, 1957 41.83 53,000 1958 October 17, 1957 42.77 59,200 1959 April 13, 1959 34.48 34,200 1960 June 26, 1960 46.4 84,100 1961 September 15, 1961 44.09 66,400 1962 November 15, 1961 29.8 21,000 1963 February 22, 1963 22.69 8,580 1964 September 19, 1964 21.96 7,800 1965 May 20, 1965 31.05 27,000 1966 December 6, 1965 25.64 15,200 1967 September 23, 1967 27.5 19,000 1968 June 26, 1968 37.49 49,500 1969 February 23, 1969 27.92 24,200 1970 May 19, 1970 26.34 21,900 1971 October 25, 1970 24.76 19,400 1972 May 13, 1972 27.34 24,600 1973 June 15, 1973 38.7 60,800 1974 September 16, 1974 32.14 38,400 1975 May 28, 1975 34.45 48,900 1976 April 22, 1976 23.47 19,900 1977 April 24, 1977 34.2 50,300 1978 September 15, 1978 22.96 19,700 1979 June 9, 1979 29.9 40,400 1980 May 19, 1980 19.2 14,300 1981 June 18, 1981 30.95 42,100
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Table 2.4S.2-1 Peak Streamflow in the Lower Colorado River at Bay City (USGS Gauge No. 08162500) (Continued) 1982 November 3, 1981 32.48 46,400 1983 May 23, 1983 22.9 22,600 1984 October 17, 1983 16.02 10,700 1985 October 25, 1984 24.6 24,500 1986 November 28, 1985 24.23 23,600 1987 June 17, 1987 34.32 50,500 1988 March 19, 1988 18.24 12,200 1989 May 16, 1989 14.6 7,740 1990 February 22, 1990 13.74 6,720 1991 April 16, 1991 24.04 23,200 1992 December 27, 1991 38.9 69,600 1993 June 22, 1993 30.28 38,500 1994 May 17, 1994 18.69 12,000 1995 October 20, 1994 38.67 71,100 1996 June 26, 1996 16.76 12,200 1997 March 19, 1997 29.29 37,900 1998 October 15, 1997 26.09 33,000 1999 October 24, 1998 40.95 81,800 2000 June 12, 2000 12.98 7,380 2001 September 1, 2001 22.36 22,800 2002 July 16, 2002 27.05 33,000 2003 November 8, 2002 32.56 48,300 2004 June 26, 2004 24.38 25,300 2005 November 27, 2004 41.73 73,800 2006 July 26, 2006 12.53 6,930 Source: Reference 2.4S.2-3
[1] Gauge height is measured from the National Geodetic Vertical Datum of 1929 (NGVD 29). [2] Peak streamflow data for 1940 water year is indicated as a historical peak in Reference 2.4S.2- 3. Peak streamflow data for all other water years may have been affected by regulation or diversion.
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Table 2.4S.2-2 Peak Streamflow in the Lower Colorado River at Wharton (USGS Gauge No. 08162000) Gauge Height [1] Streamflow [2] Water Year Date (ft) (cfs) 1919 June 18, 1919 No data 37,600 1920 October 15, 1919 No data 39,600 1921 September 14, 1921 No data 35,900 1923 May 3, 1923 No data 29,300 1924 November 5, 1923 No data 32,800 1925 May 15, 1925 No data 22,100 1935 June 20, 1935 38.2 159,000 1938 July 30, 1938 37.4 145,000 1939 July 18, 1939 11.48 12,600 1940 July 3, 1940 35.99 100,000 1941 November 26, 1940 35.3 92,000 1942 April 9, 1942 22.35 38,900 1943 October 21, 1942 9.3 8,330 1944 March 17, 1944 14.96 19,700 1945 April 2, 1945 19.8 36,400 1946 March 14, 1946 19.5 35,600 1947 November 6, 1946 16.98 27,300 1948 May 27, 1948 8.4 7,800 1949 April 27, 1949 20.9 37,900 1950 June 4, 1950 17.55 28,600 1951 June 6, 1951 11.15 13,200 1952 May 29, 1952 12.95 17,400 1953 May 1, 1953 17.9 29,900 1954 December 5, 1953 11.2 13,300 1955 May 20, 1955 10.4 10,100 1956 October 7, 1955 5.7 4,610 1957 April 30, 1957 28.9 54,200 1958 October 17, 1957 30 58,500 1959 April 13, 1959 20.6 33,300 1960 June 27, 1960 27.5 53,000 1961 September 15, 1961 30.9 59,600
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Table 2.4S.2-2 Peak Streamflow in the Lower Colorado River at Wharton (USGS Gauge No. 08162000) (Continued)
1962 November 14, 1961 15.7 21,600 1963 February 21, 1963 8.6 9,680 1964 September 19, 1964 7.3 7,990 1965 May 19, 1965 20.8 33,300 1966 May 3, 1966 12.72 16,300 1967 September 23, 1967 12.43 15,700 1968 June 26, 1968 28.06 55,400 1969 February 22, 1969 17.45 25,500 1970 May 18, 1970 17 24,600 1971 October 24, 1970 15.72 22,400 1972 May 13, 1972 16.96 24,500 1973 June 15, 1973 32.25 59,400 1974 September 15, 1974 25.9 40,800 1975 May 27, 1975 28.5 50,800 1976 April 21, 1976 18.14 21,000 1977 April 23, 1977 32.35 53,000 1978 September 14, 1978 17.7 20,300 1979 June 8, 1979 28.55 43,400 1980 May 16, 1980 13.05 13,500 1981 June 17, 1981 28.5 43,300 1982 November 3, 1981 30.55 49,300 1983 May 23, 1983 28.85 23,700 1984 May 20, 1984 16.19 5,140 1985 February 25, 1985 23.5 14,900 1986 November 27, 1985 29.94 25,400 1987 June 17, 1987 41.48 51,600 1988 March 19, 1988 22.42 12,900 1989 May 20, 1989 18.44 7,410 1990 May 6, 1990 15.77 4,470 1991 January 12, 1991 31.63 28,800 1992 December 27, 1991 45.31 61,900 1993 June 21, 1993 33.06 31,800
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Table 2.4S.2-2 Peak Streamflow in the Lower Colorado River at Wharton (USGS Gauge No. 08162000) (Continued)
1994 May 16, 1994 22.62 13,800 1995 October 20, 1994 40.69 49,600 1996 September 23, 1996 20.47 11,900 1997 March 18, 1997 31.29 30,600 1998 October 15, 1997 28.85 25,200 1999 October 23, 1998 48.72 74,800 2000 June 12, 2000 18.71 8,650 2001 March 16, 2001 23.06 14,500 2002 November 19, 2001 31.05 30,100 2003 November 8, 2002 39.16 46,000 2004 June 13, 2004 29.26 25,600 2005 November 26, 2004 48.32 73,200 2006 May 10, 2006 14.49 3,820 Source: Reference 2.4S.2-4
[1] Gauge height is measured from the NGVD 29. [2] Peak streamflow data for 1935 water year is indicated as a historical peak in Reference 2.4S.2- 4. Peak streamflow data from 1938 to 2006 water years may have been affected by regulation or diversion.
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Table 2.4S.2-3 Recorded Highest Flood Elevations at Bay City Gauge Height (ft NGVD 29 Rank or MSL) Date 1 56.10 12/10/1913 2 55.40 5/8/1922 3 55.00 6/1/1929 4 54.60 6/22/1935 5 53.40 8/2/1938 6 52.20 10/5/1936 7 47.60 11/27/1940 8 46.60 7/4/1940 9 46.40 6/26/1960 10 38.67 10/20/1994 Source: References 2.4S.2-3, 2.4S.2-5, and 2.4S.2-6
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Table 2.4S.2-4 Short Duration PMP Depths at the STP 3 & 4 Site
PMP Duration 6-hr, 10 1-hr, Point PMP Depth & Area mi2 Ratio Location Ratio Source (in) 72 hr, 10 mi2 - - HMR 51 - Fig. 22 55.7 48 hr, 10 mi2 - - HMR 51 - Fig. 21 51.8 24 hr, 10 mi2 - - HMR 51 - Fig. 20 47.1 12 hr, 10 mi2 - - HMR 51 - Fig. 19 37.8 6 hr, 10 mi2 - - HMR 51 - Fig. 18 32.0 3 hr - - Fitted from Figure 2.4S.2-3 29.7 2 hr - - Fitted from Figure 2.4S.2-3 26.6 1 hr, point location [1] 0.62 - HMR 52 - Fig. 23 19.8 30 min, point - 0.73 HMR 52 - Fig. 38 14.5 15 min, point - 0.50 HMR 52 - Fig. 37 9.9 5 min, point [2] - 0.32 HMR 52 - Fig. 36 6.4 Source: Reference 2.4S.2-10 and 2.4S.2-11
[1] The local PMP rainfall magnitude for 1 hr point location (1 mi2) exceeded the maximum rainfall rate (1 hr, 1 mi2) specified in the ABWR DCD (Tier 1 Table 5.0, and Tier 2 Table 2.0-1), which is further discussed in Table 2.0-2. [2] The local PMP rainfall magnitude for 5 min point location (1 mi2) exceeded the maximum short term rainfall rate (5 min, 1 mi2) specified in the ABWR DCD (Tier 1 Table 5.0, and Tier 2 Table 2.0-), which is further discussed in Table 2.0-2.
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Table 2.4S.2-5 Subbasin Drainage Areas
Drainage Area Sub-Basin (mi2) North 1 1.466 North 2 0.298 North 3 0.177 PBN1 0.319 PBW1 0.049 PBW 0.135 PBE 0.089 Total 2.533
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Table 2.4S.2-6 PMP Peak Discharges in STP 3 & 4 Subbasins and Drainage Elements Hydrologic Drainage Peak Discharge Runoff Volume Element Area (mi2) (cfs) Time of Peak (in) LRS 1.764 7686.9 26Jul2007, 06:35 32.04 MDC2 0.089 1428.7 26Jul2007, 03:30 31.68 MDC3 0.224 3588.4 26Jul2007, 03:35 31.68 MDC4 0.273 3937.5 26Jul2007, 03:35 31.68 North 1 1.466 7971.5 26Jul2007, 05:30 31.68 North 2 0.298 1773.1 26Jul2007, 05:15 31.68 North 3 0.177 1457.3 26Jul2007, 04:25 31.68 OutFlow 2.533 9852.0 26Jul2007, 03:35 31.93 PBE 0.089 1443.3 26Jul2007, 03:25 31.68 PBN1 0.319 4243.8 26Jul2007, 03:35 31.68 PBW 0.135 2304.4 26Jul2007, 03:25 31.68 PBW1 0.049 1367.7 26Jul2007, 03:10 31.68 US LRS 1.764 7690.3 26Jul2007, 06:25 31.96 US MDC2 0.089 1443.3 26Jul2007, 03:25 31.68 US MDC3 0.224 3635.2 26Jul2007, 03:25 31.68 US MDC4 0.273 3976.3 26Jul2007, 03:30 31.68
Floods 2.4S.2-21 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.4S.2-1 Peak Streamflow on the Lower Colorado River near Bay City, Texas (USGS gauge number 08162500) number (USGS gauge City, Texas Bay River near Colorado Lower Streamflow on the Peak Figure 2.4S.2-1 Source: Reference 2.4S.2-2 Reference Source:
2.4S.2-22 Floods Rev. 12
STP 3 & 4 Final Safety Analysis Report lorado River at Wharton, Texas (USGS gauge number 08162000) 08162000) gauge number Texas (USGS at Wharton, lorado River Figure 2.4S.2-2 Peak Streamflow on the Lower Co on Peak Streamflow 2.4S.2-2 Figure Source: Reference 2.4S.2-3 Reference Source:
Floods 2.4S.2-23 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.4S.2-3 Determination of 2- and 3-hr PMP Depths at the STP 3 & 4 Site at the and 3-hr PMP Depths of 2- Determination Figure 2.4S.2-3
2.4S.2-24 Floods Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.4S.2-4 Site Layout and Major Drainage Routes Drainage Major and Site Layout Figure 2.4S.2-4
Floods 2.4S.2-25 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.4S.2-5 Components of the Drainage System and Subbasin Areas. The vertical datum used is NGVD 1929 datum used vertical The Areas. Subbasin and System the Drainage of Components Figure 2.4S.2-5
2.4S.2-26 Floods Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.4S.2-6 HEC-HMS Model Hydrologic Diagram of the STP 3 & 4 Drainage System System Drainage of the STP 3 & 4 Diagram HEC-HMS Model Hydrologic 2.4S.2-6 Figure
Floods 2.4S.2-27 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.4S.2-7 Extents and Locations of Channel Crosssections of Channel Locations and Extents Figure 2.4S.2-7
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2.4S.3 Probable Maximum Flood (PMF) on Streams and Rivers The following site-specific supplement addresses COL License Information Item 2.15.
The STP 3 & 4 site is located near the west bank of Lower Colorado River in Matagorda County, Texas, as shown in Figure 2.4S.3-1. The site is 12 miles south-southwest of Bay City, Texas and 8 miles north-northwest of Matagorda, Texas. There are a total of 68 dams with storage capacity in excess of 5000 acre-ft upstream of the STP 3 & 4 site on the Colorado River and its tributaries, as discussed in Subsection 2.4S.4. The Lower Colorado River Authority (LCRA) operates six of these dams that together form the six Highland Lakes: Buchanan, Inks, LBJ (with Wirtz Dam), Marble Falls (with Starcke Dam), Travis (with Mansfield Dam), and Austin (Tom Miller Dam), as discussed in Subsection 2.4S.1. The Highland Lake System was designed for flood management, water supply management, and hydroelectricity generation purposes. These lakes on the Colorado River are shown in Figure 2.4S.1-6.
In this subsection the Probable Maximum Flood (PMF) in the Lower Colorado River is analyzed to assess the flooding potential on the safety-related facilities at the STP 3 & 4 site. Several publicly available flood hydrologic studies performed on the Lower Colorado River basin from 1985 to 2002 (References 2.4S.3-1 to 2.4S.3-8) by Federal, State, and other local agencies were reviewed to establish the combination of events that constitute the probable maximum flood condition at the STP 3 & 4 site.
The following probable maximum flood studies were reviewed:
Possible PMF scenarios considered for STP 1 & 2 and reported in the Updated Final Safety Analysis Report (UFSAR) (Reference 2.4S.3-1).
PMF estimates and dam safety evaluation studies for Mansfield Dam by the United States Bureau of Reclamation (USBR) (References 2.4S.3-2, 2.4S.3-3, and 2.4S.3-4) and others (References 2.4S.3-5 and 2.4S.3-6).
Dam safety evaluation project for the six Highland Lakes in the Lower Colorado River (from Lake O.H. Ivie to Mansfield Dam), Phase II (Preliminary Design and Final Design), by Freese & Nichols Inc. (Reference 2.4S.3-7).
Flood damage evaluation project for the Lower Colorado River (from Lake O.H. Ivie to the Gulf of Mexico at Matagorda Bay) by Halff Associates Inc. (Reference 2.4S.3-8).
A brief overview of each of these studies is given in Subsection 2.4S.3.4.1.
The possible PMF scenarios considered for the existing STP 1 & 2 (Reference 2.4S.3- 1) were evaluated for their applicability to the present and forecast future conditions of the Lower Colorado River based on information provided in the hydrologic studies reviewed (References 2.4S.3-2, 2.4S.3-7, and 2.4S.3-8) and in the Region “K” Plan of the 2007 State Water Plan adopted by the Texas Water Development Board (TWDB) (see Section 8.4.2 in Reference 2.4S.3-23). Based on this evaluation, the following
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three possible PMF scenarios were selected to determine the maximum flood elevation caused by river and stream flooding at the STP 3 & 4 site.
Scenario 1 The flow resulting from the PMF for the drainage area between Mansfield Dam and the Bay City United States Geological Survey (USGS) gauging station (see Figure 2.4S.1-8) combined with an antecedent storm equal to 40% of the PMP occurring over the same drainage area (3555 sq. mi), three days before the PMF. This combined flow is added to the flow release of 90,000 cfs from Mansfield Dam and to the base flow at Bay City to determine the peak PMF flow for this scenario.
The flow release from Mansfield Dam is added to this scenario to accommodate any rainfall contributions upstream of the Mansfield Dam during the PMF event. The “Water Management Plan for the Lower Colorado River Basin” (Reference 2.4S.3-26) states that “if the reservoir level is forecast to exceed 714 ft MSL but not to exceed 722 ft MSL: release will be made at 90,000 cfs” from the Mansfield Dam. It also states that “if the reservoir level is forecast to exceed 722 ft MSL, the Bureau of Reclamation will schedule releases as required for the safety of the structure.”
Scenario 2 The flow resulting from the PMF inflow hydrograph to Mansfield Dam, generated by the PMP storm over the watershed upstream of the dam (from Lake O.H. Ivie to Mansfield Dam), routed through Lake Travis and combined with the flood hydrograph from a sequential storm equal to 40% of the PMP occurring over the drainage area between Mansfield Dam and Bay City (3555 sq. mi), three days after the PMP storm upstream of Mansfield Dam. This combined flow is added to the base flow at Bay City to determine the peak PMF flow for this scenario. The total contributing drainage area for this scenario is about 18,197 sq. mi.
Scenario 3 The flow resulting from the PMF for the entire Lower Colorado River basin area between Lake O.H. Ivie and Bay City (18,197 sq. mi) combined with the flood hydrograph from an antecedent storm equal to the Standard Project Storm (SPS)1 for the same drainage area occurring three days before the PMF. This combined flow is added to the base flow at Bay City to determine the peak PMF flow for this scenario. This scenario does not account for the storage effect of Lake Travis at Mansfield Dam. The total contributing drainage area for this case is about 18,197 sq. mi.
From these three possible PMF flow scenarios, the most critical flow scenario, which produces the highest PMF peak at the Bay City gauging station, is selected to evaluate flooding potential at the STP 3 & 4 site. The Bay City gauging station is located about 18 miles upstream from the STP
1 ANSI/ANS 2.8 (Reference 2.4S.3-13) states that the antecedent storm should be equal to 40% of the PMP or the 500-yr storm, whichever is less. However, for this scenario, the SPS event is adopted conservatively as the antecedent storm, considering the fact the SPS event produces a higher flood peak compared to the 500-yr event (see Vol. II-B, Chapter 4, Table VI-7 Reference 2.4S.3-8).
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reservoir makeup pumping facility located on the west bank of Lower Colorado River (see Figure 2.4S.3-1). The discussions on the PMF developments of these three scenarios are given in Section 2.4.S.3.4.2.
In this subsection, failure of the upstream dams was not considered as part of these probable maximum flood scenarios. The implications of potential hydrological dam failures are discussed in Subsection 2.4S.4.
2.4S.3.1 Probable Maximum Precipitation (PMP) PMP depths for the drainage basins upstream of the STP 3 & 4 site were derived following the procedures described in the National Weather Service (NWS) Hydrometeorological Reports 51 and 52 (HMR 51 and 52) (References 2.4S.3-10 and 2.4S.3-11). The PMP estimates obtained from the HMR 51 and 52 procedures are location-specific and have accounted for orographic and seasonal effects.
The PMP storm spatial distribution, centering, and orientation pattern adopted for the drainage basin upstream of STP 3 & 4 site were determined as follows:
The storm spatial distribution for the PMP was selected based on the procedures in HMR 51 and 52 (References 2.4S.3-10 and 11), as discussed in detail in Subsection 2.4S.3.4.1.4.
A critical storm centering approach that produces the largest peak flow rate at the STP 3 & 4 site for the PMP event was determined in a manner that maximizes the volume of precipitation within the basin, as discussed in detail in Subsection 2.4S.3.4.1.4.
Two different storm orientation patterns were analyzed for the Lower Colorado River basin to derive the most critical PMF flood hydrographs at STP 3 & 4 site. A detailed description of the orientation patterns used for the analyses is provided in Subsection 2.4S.3.4.1.4.
Halff Associates Inc. adopted a storm duration of 96 hours for the rainfall hyetographs used for the Lower Colorado River flood damage evaluation study (see Vol. II-B, Chapter 4, pg. 18 of Reference 2.4S.3-8). The Halff study stated that “a 96-hour storm duration was selected because the upper basin peak could travel to Mansfield Dam during that period and storm events below Mansfield Dam could reach Wharton2 by the end of the storm event.” The UFSAR also adopted the 96-hour storm duration for the PMP hyetograph used for the STP 1 & 2 site (Reference 2.4S.3-1). Thus, a 96-hour storm duration was selected for the PMP hyetograph developed for the STP 3 & 4 site in Subsection 2.4S.3.4.2.1. The time distribution of the 96-hour rainfall hyetographs adopted in the Halff study was used to derive PMP hyetographs for the drainage basins upstream of the STP 3 & 4 site in Subsection 2.4S.3.4.2.1.
2 It should be noted that the difference in drainage areas at Wharton (30,600 sq. mi) and Bay City (30,837 sq. mi) gauging stations is less than 1% of the contributing drainage area at Bay City (Vol. II-B, Chapter 4, Table IV-1 of Reference 2.4S.3-8).
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Investigations of climate, the occurrence of snow, and ice effects within the Colorado River Basin and the effects on flood-producing phenomena indicated that Section 2.4S.1.2.1.1, Reference 2.4S.3-1, and Subsection 2.4S.7, respectively. Previous investigations of the Probable Maximum Flood (e.g., Reference 2.4S.3-2, p. 5) have noted that frequent and intense rainfall events occurring simultaneously over several sub-basins of the Colorado River have produced the largest recorded floods in the watershed. The occurrence of flooding from snow melt or antecedent snowpack was not considered a factor in the PMF analysis of Mansfield Dam by the US Bureau of Reclamation (Reference 2.4S.3-2), the Halff study (Reference 2.4S.3-8), or 2006 Region K Water Plan (Reference 2.4S.3-23). Therefore, snow melt and antecedent snow pack are not considered as factors in flooding for the STP 3 & 4 site.
The PMP estimates for the subbasins between Mansfield Dam and the STP 3 & 4 site are provided in Subsection 2.4S.3.4.2.1.
2.4S.3.2 Precipitation Losses The rainfall-runoff analysis requires estimation of initial rainfall loss and constant rainfall loss rate to determine the direct runoff hydrograph corresponding to the excess rainfall (i.e. total rainfall minus rainfall loss). The initial rainfall loss quantifies the amount of infiltrated or stored rainfall before surface runoff begins. The constant rainfall loss rate determines the rate of infiltration that will occur after the initial loss is satisfied. Conservative assumptions were made for initial and constant loss rates to account for absorption and wet watershed antecedent conditions that would maximize the PMF peak flow, as discussed in detail in Subsection 2.4S.3.4.2.1.
2.4S.3.3 Runoff and Stream Course Models The PMF hydrograph for the drainage area between Mansfield Dam and Bay City was estimated using the HEC-HMS model developed by Halff Associates Inc. (Reference 2.4S.3-8). This model included the calibrated rainfall losses (i.e. initial loss and constant loss rate) and the Snyder unit hydrograph parameters (i.e. basin lag-time and peaking coefficient) for each of the subbasins located between Mansfield Dam and Matagorda Bay (see Vol. II-B, Chapter 4, Attachment B-1 of Reference 2.4S.3-8). A total of 80 subbasins are included in the lower part of the river basin from Mansfield Dam to Matagorda Bay as shown in Figures 2.4S.3-2(a) and 2(b). The subbasin drainage areas (between Mansfield Dam and Bay City) and the calibrated Snyder unit hydrograph parameters used for the analysis are presented in Subsection 2.4S.3.4.2.1.
Because the Halff HEC-HMS model was calibrated only for floods up to the 100-year storm event, the calibrated unit hydrograph basin lag-time parameter for each subbasin was conservatively decreased by 25% to account for non-linearity effects in the runoff process under extreme flood conditions such as the PMF based on recommendations stated in the United States Army Corps of Engineers EM 1110-2- 1417 (Reference 2.4S.3-24). The modified unit hydrograph basin lag-time parameters used for the PMF analysis are presented in Subsection 2.4S.3.4.2.1, for the subbasins from Mansfield Dam to Matagorda Bay.
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In the Halff HEC-HMS model, the flow routing from an upstream reach to a downstream reach was performed using the modified Puls method, which defined a storage-outflow rating curve for each of the channel reaches in the model (see Vol. II- B, Chapter 4, pg. 26 and pg. 29 of Reference 2.4S.3-8). Because the Halff HEC-HMS model (developed for the lower part of river basin) was calibrated only for floods up to the 100-year storm event, it was also necessary to revise the storage-outflow channel rating curves for a few channel reaches between Mansfield Dam and Matagorda Bay to accommodate the PMF conditions. Only three out of a total of 58 channel rating curves needed to be revised. The rating curves for these three channel reaches were extended by linear extrapolation.
2.4S.3.4 Probable Maximum Flood Flow 2.4S.3.4.1 Previous Hydrologic Studies for Lower Colorado River The following publicly available hydrologic and hydraulic studies performed for the Lower Colorado River basin by Federal, State, and other local agencies were reviewed in detail to determine PMF conditions in Lower Colorado River and their potential to flood the facilities at the STP 3 & 4 site. These studies were listed in the beginning of Subsection 2.4S.3 and are discussed in detail in this subsection.
2.4S.3.4.1.1 PMF Flow Scenarios at the STP 1 & 2 Site – UFSAR The UFSAR prepared for the existing STP 1 & 2 (Reference 2.4S.3-1) evaluated five hydro-meteorologically critical flow scenarios for the Lower Colorado River and selected among these the most critical PMF flow scenario to determine the maximum flood elevation at the STP 1 & 2 site. This study also included a proposed dam at Columbus Bend that was under consideration in the 1960s. These five PMF flow scenarios are summarized as follows (Reference 2.4S.3-1):
The Spillway Design Flood (SDF) for the proposed Columbus Bend Dam, which would result from a Probable Maximum Precipitation (PMP) storm on the watershed above the dam, was routed to the STP 1 & 2 site. It was assumed that this event would occur in coincidence with the peak of a Standard Project Flood (SPF) from the 755 sq. mi drainage area between the proposed Columbus Bend Reservoir and the STP 1 & 2 site. It was assumed that the peaks of these two floods would be directly additive and that they would occur simultaneously with a base flow of 50,000 cfs. The peak flow at Bay City for this scenario was estimated to be equal to 958,000 cfs (SDF: 648,000 cfs + SPF: 260,000 cfs + base flow: 50,000 cfs) at the STP 1 & 2 site.
The PMF for the drainage area between Mansfield Dam and Bay City was assumed to occur three days after the occurrence of the SPF over the same area. A base flow of 50,000 cfs was adopted. The peak flow at Bay City for this scenario was estimated to be equal to 913,000 cfs, which includes a base flow of 50,000 cfs.
The SDF outflow hydrograph from Mansfield Dam, which results from the PMF inflow hydrograph into Lake Travis caused by a PMP storm on the watershed above the dam, was routed to the STP 1 & 2 site. This was combined with a SPS
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occurring over the drainage area between Mansfield Dam and the STP 1 & 2 site, three days after the PMP storm producing the Mansfield Dam SDF. It was also assumed that a base flow of 50,000 cfs occurs simultaneously with the resulting flood. The peak flow for this scenario was estimated to be equal to 698,000 cfs, which includes a base flow of 50,000 cfs.
The PMF for the drainage area between the proposed Columbus Bend Dam and the STP 1 & 2 site was assumed to occur in coincidence with an SPF peak discharge from the proposed dam. It was also assumed that a base flow of 50,000 cfs occurs simultaneously with the resulting flood. The peak PMF for this scenario was estimated to be equal to 894,000 cfs, (PMF: 520,000 cfs + SPF: 324,000 cfs + base flow: 50,000 cfs) at the site.
A hypothetical PMF for the entire contributing drainage area of the Lower Colorado River basin above the STP 1 & 2 site was assumed, with no credit taken for flood control in the numerous reservoirs upstream from Mansfield Dam, including Lake Travis. The peak PMF for this scenario was estimated to be equal to 1,750,000 cfs.
The PMF flows in the UFSAR for STP 1 & 2 (Reference 2.4S.3-1) were derived based on PMP depths that were calculated according to the procedures outlined in Hydrometeorological Reports 51 and 52 (HMR 51 and 52) (References 2.4S.3-10 and 2.4S.3-11). These reports provide the most up-to-date procedures that replace those originally presented in Hydrometeorological Report 33 (HMR 33) (Reference 2.4S.3- 9).
2.4S.3.4.1.2 PMF at Mansfield Dam - USBR and Others The most recent publicly available PMF inflow hydrograph into Mansfield Dam was established in November 1985 by the USBR (Reference 2.4S.3-2) and was developed using the procedures outlined in HMR 51 and 52 (References 2.4S.3-10 and 2.4S.3- 11). According to the USBR study, the peak PMF inflow into Mansfield Dam was estimated to be equal to 931,600 cfs.
In July 1989, ATC Engineering Consultants Inc. (ECI) prepared a dam safety evaluation report (Reference 2.4S.3-5) for Mansfield Dam, using the PMF inflow hydrograph established by the USBR in 1985. This report concluded that when all the bottom outlet gates are closed, the PMF outflow (or SDF) hydrograph has a peak discharge of 602,210 cfs with maximum reservoir water surface elevation at 750.28 ft NGVD29 (also referred to as MSL vertical datum) (Reference 2.4S.3-5).
In March 2003 (Reference 2.4S.3-3), the USBR reviewed the spillway of Mansfield Dam for its design, analysis, and construction features and confirmed the PMF hydrograph with a peak inflow of 931,600 cfs, which was established in 1985 (Reference 2.4S.3-2).
The USBR official website states that the PMF inflow to Mansfield Dam is 931,600 cfs (Reference 2.4S.3-4), i.e. the same as that published by USBR in November 1985.
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2.4S.3.4.1.3 Dam Safety Evaluation for Highland Lakes – Freese & Nichols In August 1992, Freese & Nichols Inc. (Reference 2.4S.3-7) performed a dam safety evaluation study for the six Highland Lakes in the Lower Colorado River, including Lake Travis at Mansfield Dam, as part of the dam safety compliance study for the Lower Colorado River Authority (LCRA). The watershed area for this study extended from the Lake O.H. Ivie Reservoir to Mansfield Dam and was divided into 41 subbasins (Reference 2.4S.3-7).
The computer models used for this study included HMR 52 for PMP estimates, HEC- 1 for rainfall-runoff analysis, and NETWORK for runoff routing (Reference 2.4S.3-7). The subbasin unit hydrographs and rainfall loss rates used in the HEC-1 model and channel roughness coefficients used in the NETWORK model were calibrated based on selected historical flood events in the Lower Colorado River.
In the Freese & Nichols study, PMF levels for the six Highland Lakes, including the PMF at Mansfield Dam, were calculated using the PMP depths derived from procedures outlined in HMR 51 and 52 (References 2.4S.3-10 and 2.4S.3-11). In computing the peak PMF water levels at Mansfield Dam, an antecedent storm event was routed through Lake Travis, before the PMF hydrograph. For this routing, Freese & Nichols (Reference 2.4S.3-7) assumed that the antecedent storm event was equal to 20% of the PMP, which was estimated using the HMR 51 and 52 (References 2.4S.3-10 and 2.4S.3-11).
This study concluded that the PMF outflow hydrograph at Mansfield Dam has a peak discharge of 837,094 cfs and that the maximum water surface elevation at the dam for this flood event was 752.02 ft NGVD29 (Reference 2.4S.3-7).
2.4S.3.4.1.4 Flood Damage Evaluation for Lower Colorado River - Halff Associates In July 2002, Halff Associates Inc. completed a comprehensive flood damage evaluation study for the Lower Colorado River basin (Reference 2.4S.3-8). The study area extended from Lake O.H. Ivie to the Gulf at Matagorda Bay (see Figure 2.4S.3-3) with a total contributing drainage area of about 18,300 sq. mi. This overall study area was divided into 290 subbasins (see Vol. II-B, Chapter 4, Figures III-2 to III-5 of Reference 2.4S.3-8) to include major reservoirs, major tributary confluences, and the existing USGS stream gauging stations.
The USACE HEC-HMS model, Version 2.2.2 (Reference 2.4S.3-17) was used for this study as the hydrologic modeling framework to determine frequency flood hydrographs resulting from selected storm events with return periods of 2, 5, 10, 25, 50, 100, and 500-year and the Standard Project Storm. The HEC-HMS models developed for the Halff study were initially calibrated using three historic storm events selected based on availability of adequate rainfall gauge data. The selected three storm events occurred in June 1997, October 1998, and November 2000 (see Vol. II-B, Chapter 4, pg. 12 of Reference 2.4S.3-8). The calibrated HEC-HMS model parameters included: initial rainfall loss, constant rainfall loss rate, Snyder’s basin lag-time, and Snyder’s peaking coefficient (see Vol. II-B, Chapter 4, pg. 16 of Reference 2.4S.3-8). Also, the Halff study noted that "six special Points-of-Interest (POI's) were selected as target
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locations to compute/calibrate critical peak flow hydrographs (in addition to other, less critical gauge locations). These POI's were selected based on their location in the basin and because they were identified as key calibration points for this study. The six POI's are the Llano River at Llano, the San Saba River at San Saba, Lake Buchanan, Lake Travis, Colorado River at Bastrop, and the Colorado River at Wharton" (Vol. II-B, Chapter 4, pg. 1 of Reference 2.4S.3-8). Additionally, "further adjustments to parameters, specifically loss rates, were necessary to match the peak discharges (historical frequencies) at the six POI's. Results compared closely to the historical frequency analysis results and the period-of-record analysis results." These initially calibrated model parameters were further adjusted to match the peaks of historic flood frequencies estimated at various stream gauging stations located within the study area (see Vol. II-B, Chapter 4, pg. 23 of Reference 2.4S.3-8).
The synthetic precipitation data used for this study were obtained from Hydro-35 (Reference 2.4S.3-19), TP-40 (Reference 2.4S.3-20), and TP-49 (Reference 2.4S.3- 21) for the storm events with return periods of 2, 5, 10, 25, 50, 100, and 500 years. For the SPS event, the SPF Index Rainfall was used. The storm spatial distribution, centering, and orientation pattern adopted for the Halff study were as follows:
The storm spatial distribution was selected based on the procedures in HMR 51 and 52 (References 2.4S.3-10 and 2.4S.3-11) for storm events with return periods of 2, 5, 10, 25, 50, 100, and 500 years (see Vol. II-B, Chapter. 4, pg. 18 of Reference 2.4S.3-8).
A critical storm centering approach was used for all the storm events (i.e. 2-, 5-, 10-, 25-, 50-, 100-, and 500-year storm and SPS). Using a trial and error approach, the storm center that produces the largest peak flow rate at a particular point-of- interest (POI) was determined as the critical storm center for that return period (see Vol. II-B, Chapter. 4, pg. 18 of Reference 2.4S.3-8).
Two different storm orientation patterns were adopted for the Lower Colorado River basin; one for the upper part of the basin and the other for the lower part of the basin, to derive frequency flood hydrographs at different POIs. For example, the storm orientation pattern shown in Figure 2.4S.3-4 was used to estimate flood hydrographs at different POI’s in the upper part of the basin, including Mansfield Dam (see Vol. II-B, Chapter. 4, Figure VI-1 of Reference 2.4S.3-8). The orientation pattern shown in Figure 2.4S.3-5 was used to estimate flood hydrographs at different POI’s in the lower part of the basin, including Bay City (see Vol. II-B, Chapter. 4, Figure VI-5 of Reference 2.4S.3-8).
Based on the storm orientation pattern adopted for the upper part of the river basin, the peak SPF inflow to Mansfield Dam was estimated to be 801,996 cfs3, with the critical storm center located at subbasin LR-24 (Vol. II-B, Chapter. 4, Table VI-5 of Reference
3 The value of 801,996 cfs for the peak of the SPF peak inflow into Mansfield Dam was extracted from the computer files obtained from Halff Associates Inc. In the report documenting this work (Reference 2.4S.3-8) this peak inflow was rounded to 800,000 cfs (see Vol. II-B, Chapter. 4, Table VI-5 of Reference 2.4S.3-8).
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2.4S.3-8) for unregulated flow conditions upstream of Mansfield Dam. Based on the same storm orientation pattern, with the critical storm center located at subbasin SS- 18, and the unregulated flow conditions, the peak SPF at the Wharton USGS gauging station was estimated to be 423,321 cfs4, (Vol. II-B, Chapter. 4, Table VI-7 of Reference 2.4S.3-8). The Wharton gauge is located at the Wharton POI shown on Figure 2.4S.3-3. The unregulated flow conditions used to obtain these estimates were based on the assumption that there are no dams or reservoirs in the river basin.
2.4S.3.4.1.5 Review Summary Table 2.4S.3-1 summarizes the reported PMF and SPF values at Mansfield Dam in the hydrologic studies reviewed in Subsections 2.4S.3.4.1.1 to 2.4S.3.4.1.4.
2.4S.3.4.2 PMF Flow Scenarios at STP 3 & 4 The five flood scenarios of possible PMF flows in the Lower Colorado River that were considered for the STP 1 & 2 (see Subsection 2.4S.3.4.1.1) were first evaluated for their applicability in determining the maximum flood elevation at the STP site for the present conditions. After careful consideration of the hydro-meteorological setting of the region, it was determined that the five flood scenarios considered for the STP 1 & 2 cover the permutation of the possible critical flood events that could occur in the region, thus acceptable for the evaluation of possible extreme flood conditions for the STP 3 & 4.
The first and fourth scenarios considered for STP 1 & 2 (see Subsection 2.4S.3.4.1.1) were eliminated because they include the Columbus Bend Dam that was proposed in the 1960s and which met with opposition by different groups at various times. This dam was also referred to later as the Shaw Bend Dam. Plans for the construction of this dam have been abandoned. This was confirmed by conducting an online search, a search of various sources, as well as inquiries to different engineers of the LCRA, none of which revealed any information regarding continuing plans for the construction of the Columbus Bend Dam. The recently published Region “K” Plan for the Lower Colorado Region in the 2007 State Water Plan also states that “Large local opposition to this project was demonstrated at the various Lower Colorado River Water Planning Group (LCRWPG) public meetings and in correspondence during the 2001 LCRWPG plan preparation.” The Planning Group’s recommendation in the current water plan is to oppose the potential designation of the Shaw Bend site as a potential reservoir site (see Section 8.4.2 in Reference 2.4S.3-23). Therefore, it was concluded it is not likely that this dam will be constructed in the future.
The three remaining possible PMF flow scenarios in Lower Colorado River that are analyzed for their effects at STP 3 & 4 are as follows:
4 The value of 423,321 cfs for the peak of the SPF peak at Wharton was extracted from the computer files obtained from Halff Associates Inc. In the report documenting this work (Reference 2.4S.3-8) this peak inflow was rounded to 425,000 cfs (see Vol. II-B, Chapter. 4, Table VI-7 of Reference 2.4S.3-8).
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(1) The PMF for the drainage area between Mansfield Dam and the Bay City USGS gauging station (3555 sq. mi) combined with an antecedent storm equal to 40% of the PMP occurring over the same drainage area, three days before the PMF. This combined flow is added to the flow release from Mansfield Dam and to the base flow at Bay City to determine the peak PMF flow for this scenario (see Subsection 2.4S.3).
(2) The PMF inflow hydrograph to Mansfield Dam, which results from a PMP storm on the watershed upstream of the dam (from Lake O.H. Ivie to Mansfield Dam), routed through Lake Travis and combined with the flood hydrograph from a sequential storm equal to 40% of the PMP occurring over the drainage area between Mansfield Dam and Bay City (3555 sq. mi), three days after the PMP storm upstream of Mansfield Dam. This combined flow is added to the base flow at Bay City to determine the peak PMF flow for this scenario.
(3) The PMF for the Lower Colorado River basin area between Lake O.H. Ivie and Bay City (18,197 sq. mi) combined with the flood hydrograph from an antecedent storm equal to the SPS over the same area, occurring three days before the PMF. This combined flow is added to the base flow at Bay City to determine the peak PMF flow for this scenario. Conservatively, this scenario does not account for the storage effect of Lake Travis at Mansfield Dam nor any other dam in the Lower Colorado River basin.
From these three possible PMF flow scenarios, the most critical flow scenario, which would produce the highest PMF peak at the Bay City gauging station, is selected to evaluate flooding potential at the STP 3 & 4 site. The Bay City gauging station is located about 18 river miles upstream of the STP Reservoir Makeup Pumping Facility (RMPF) on the west bank of Lower Colorado River (see Figure 2.4S.3-1).
2.4S.3.4.2.1 PMF between Mansfield Dam and Bay City for Scenario 1 For Scenario 1, the peak PMF for the drainage area between Mansfield Dam and Bay City (3555 sq. miles) was calculated by assuming an antecedent storm equal to 40% of the PMP occurs over the same area three days before the PMF event itself and combining those flows with the flow release from Mansfield Dam and the base flow at Bay City (Subsection 2.4S.3). The analysis performed to determine the peak PMF for Scenario 1 is described below.
HEC-HMS Rainfall-Runoff Model
The PMF hydrograph for the drainage area between Mansfield Dam and Bay City (3555 sq. miles) was estimated using the HEC-HMS model developed by Halff Associates Inc. for the lower part of the river basin with the storm orientation pattern shown in Figure 2.4S.3-5 (Subsection 2.4S.3.4.1.4). This model consists of 80 subbasins between Mansfield Dam and Matagorda Bay.
In the Halff HEC-HMS model, the flow routing from an upstream reach to a downstream reach was performed using the modified Puls method, which defines a
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storage-outflow rating curve for each of the channel reaches in the model. As discussed in Subsection 2.4S.3.3, three storage-outflow rating curves (out of 58) in the original Halff HEC-HMS model were extended to accommodate the PMF conditions. Note that there are nine dams/reservoirs with individual storage capacity in excess of 3000 acre-feet, but none of these reservoirs were included in the Halff HEC-HMS model. Only major reservoirs were included in the Halff study since "the effects of numerous other smaller reservoirs in the Colorado River Basin were considered to be insignificant to the overall accuracy of the study and impractical to model on a daily basis for a long period of record" (Vol II-A, Chapter 2, pg. 2 of Reference 2.4S.3-8). Additionally, including these reservoirs in the model would produce a less conservative estimate of discharge due to attenuation of the flood peak by the reservoirs.
Other input data to the HEC-HMS model included the unit hydrograph, the rainfall hyetograph, and rainfall losses for each of the subbasins in the lower part of the river from Mansfield Dam to Matagorda Bay as described below.
Unit Hydrograph: The HEC-HMS model developed by Halff Associates Inc. included the calibrated Snyder unit hydrograph parameters (i.e. the basin lag-time and peaking coefficient) for each of the subbasins located between Mansfield Dam and Matagorda Bay (Subsection 2.4S.3.4.1.4). As discussed in Subsection 2.4S.3.3, the calibrated Snyder basin lag-time parameter for each of the subbasins was decreased by 25% to account for non-linearity effects in the runoff process under PMF conditions (Reference 2.4S.3-24).
Table 2.4S.3-2 presents the drainage areas and the unit hydrograph parameters for the subbasins from Mansfield Dam to Matagorda Bay extracted from the calibrated HEC-HMS model (see also Vol. II-B, Chapter. 4, Attachment B-1 of Reference 2.4S.3- 8) and the Snyder lag times as modified to account for non-linearity effects.
Rainfall Hyetograph: PMP hyetographs were developed for each of the 80 subbasins located within the lower part of the river basin presented in Table 2.4S.3-2, using the same storm spatial distribution and the critical storm centering location adopted by the Halff study (see Subsection 2.4S.3.4.1.4) as follows:
In the Halff study, the critical storm centering location that produces the largest flow rate at Bay City for the 100-year storm event was found to be at subbasin CC-06, as shown in Figure 2.4S.3-3 (see Vol. II-B, Chapter. 4, Table VI-11 of Reference 2.4S.3-8). Considering the unique elongated shape of the lower part of the Lower Colorado River basin (from Mansfield Dam to Matagorda Bay) and the storm orientation, it is reasonable to assume that the same critical storm centering location can be used for the PMP event.
The storm spatial distribution pattern adopted by the Halff study was based on the procedures in HMR 52 (Reference 2.4S.3- 11). The same procedures were used to spatially distribute the 96-hour PMP depth at subbasin CC-06 to the remaining subbasins.
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2 The 96-hour 10-mi PMP depth for subbasin CC-06 was estimated as 55.7 inches by extrapolating data obtained from Figures 18 to 22 in HMR 51 (see Table 2.4S.3- 3). The PMP hyetograph for subbasin CC-06 is shown in Figure 2.4S.3-6.
The PMP hyetographs for the remaining 79 subbasins are the same, except that the rainfall intensity ordinates are multiplied by the ratio of the PMP depth for that subbasin (obtained from Table 2.4S.3-2) to the PMP depth at subbasin CC-06 (55.7 inches, according to Table 2.4S.3-3).
Rainfall Losses: The unit hydrograph approach requires estimation of initial rainfall loss and constant rainfall loss rate to determine the direct runoff hydrograph corresponding to the excess rainfall (i.e. total rainfall minus rainfall loss). The initial rainfall loss quantifies the amount of infiltrated or stored rainfall before surface runoff begins. The constant rainfall rate determines the rate of infiltration that is sustained during the rest of the storm after the initial loss is satisfied.
The PMF peak flow is often insensitive to the initial rainfall loss (Reference 2.4S.3-12); therefore, this value was conservatively set equal to zero for each of the 80 subbasins in the HEC-HMS model (see Table 2.4S.3-2). Reference 2.4S.3-12 also states that “for PMF runoff computations, the soil should be assumed to be saturated with infiltration occurring at the minimum rate applicable to the area-weighted average soil type covering each subbasin.” Therefore, based on data provided in Table 8-8.1 of Reference 2.4S.3-12, a minimum uniform rainfall loss rate of 0.05 in/hr was adopted in the model for the PMF analysis (see Table 2.4S.3-2). The minimum uniform rainfall loss rate of 0.05 in/hr used in the model for the PMF analysis was based on a range of 0.05 to 0.15 in/hr provided in Table 8-8.1 of Reference 2.4S.3-12. These conservative values were used in the model to account for absorption and wet watershed antecedent conditions that would maximize the peak PMF discharges for subbasins listed in Table 2.4S.3-2. The use of minimum values for the rainfall loss rates increases the runoff volume of the PMF hydrograph and hence provides a conservatively higher peak PMF discharge.
Base Flow: The base flow rate at Bay City is estimated in accordance with the procedures in ANSI/ANS-2.8-1992 (Reference 2.4S.3-13), which states that the mean monthly flow should be used as the base flow rate for the PMF analysis. The base flow rate at Bay City was conservatively set equal to the mean monthly average flow of 5200 cfs. This value was selected based on the published USGS mean monthly flow statistics at Austin (08158000), Columbus (08161000), and Bay City (08162500).
Peak PMF Discharge at Bay City for Scenario 1: The PMF hydrograph for the drainage area between Mansfield Dam and Bay City was estimated using the HEC-HMS model obtained from Halff Associates Inc. (Reference 2.4S.3-8) with the input data described above. The peak discharge for this PMF hydrograph (without an antecedent storm event and a base flow) was estimated to be 1,096,807 cfs, (see Figure 2.4S.3-7). As shown in Figure 2.4S.3-7, combining the PMF with an antecedent storm event equal to 40% of the PMP over the same drainage area occurring three days before the PMF event, the flow release of 90,000 cfs from Mansfield Dam (see Subsection 2.4S.3), and
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the base flow of 5200 cfs gives a peak PMF discharge at Bay City of 1,397,432 cfs (see Figure 2.4S.3-7).
2.4S.3.4.2.2 PMF between Mansfield Dam and Bay City for Scenario 2 For Scenario 2, the PMF inflow hydrograph to Mansfield Dam is routed through Lake Travis and combined with the flood hydrograph from a sequential storm event equal to 40% of the PMP over the drainage area between Mansfield Dam and Bay City and the base flow at Bay City. The sequential storm event occurs three days after the PMP storm that produces the PMF inflow hydrograph into Lake Travis at Mansfield Dam.
The PMF inflow hydrograph into Lake Travis was estimated based on the SPF inflow hydrograph developed for the basin upstream of Mansfield Dam with unregulated flow conditions as reported in the Halff study (see Subsection 2.4S.3.4.1.4). The PMF inflow was taken as equal to two times the SPF inflow into Lake Travis at Mansfield Dam. This assumption is based on guidelines given in the United States Army Corps of Engineers E.M. 1110-2-1411 (Reference 2.4S.3-14), which states that the SPF is usually equal 40 to 60% of the PMF for the same basin. A ratio of 50% is adopted in this PMF analysis.
The critical storm centering location for this SPF inflow hydrograph at Mansfield was found to be at subbasin LR-24, as shown in Figure 2.4S.3-3 (Vol. II-B, Chapter. 4, Table VI-5, Reference 2.4S.3-8).
Routing of PMF Hydrograph through Lake Travis: The SPF inflow hydrograph at Mansfield Dam was routed through Lake Travis, using the United States Army Corps of Engineers HEC-1 model (Reference 2.4S.3-15), in order to establish the antecedent water level conditions in the reservoir. The SPF inflow hydrograph was assumed to occur three days prior to the routing of the PMF inflow hydrograph that was estimated as equal to two times the SPF inflow. The input data used in the HEC-1 model for the reservoir routing analysis are briefly described below:
The initial reservoir water level prior to the routing of the SPF inflow hydrograph was set at elevation 681 ft NGVD29, i.e. the elevation of the reservoir conservation pool (see Table 2.4S.3-4).
The reservoir elevation-storage data up to El. 740 ft NGVD29 were obtained from the Halff Reservoir Operation Model HEC-5 (see Vol. II-B, Chapter 5, Reference 2.4S.3-8) and are presented in Table 2.4S.3-5. The storage values above El. 740 ft NGVD29 were estimated by logarithmic extrapolation of the Halff data.
The pertinent dam and spillway outlet data were obtained from various USBR publications (References 2.4S.3-4, 2.4S.3-5, and 2.4S.3-16), the Freese & Nichols study (Reference 2.4S.3-7), and from the Halff study (Reference 2.4S.3-8) and are presented in Table 2.4S.3-4. The main spillway at Mansfield Dam is an uncontrolled ogee crest spillway with a 700 ft clear length and crest at El. 714 ft NGVD29 (Reference 2.4S.3-5). The low level outlets consist of twenty-four 102-in diameter conduits through the concrete section of the dam controlled by gates.
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The centerline elevation of the inlets to the conduits is at El. 540 ft NGVD29 (Reference 2.4S.3-5).
The main spillway rating curve for Mansfield Dam was computed from spillway capacity data given in References 2.4S.3-4, 2.4S.3-8, and 2.4S.3-16. The discharge coefficient for the spillway is C = 4.0 in the expression Q = CLH1.5, where Q is the spillway discharge, L is the spillway length, and H is the head over the spillway crest. This value is based on the model test result of C = 3.93 at the spillway design head and calculation of C value at other heads in accordance with data in Reference 2.4S.3-22.
A rating curve for the 24 low level outlets was also developed from data given in References 2.4S.3-4, 2.4S.3-8, and 2.4S.3-16. The low level outlets were treated as orifices in the HEC-1 model with a discharge coefficient of 0.87. The total discharge from all 24 outlet conduits with Lake Travis at El. 714 ft NGVD29 is 126, 000 cfs (Reference 2.4S.3-5).
The combined inflow hydrograph (SPF + PMF) into the Lake Travis reservoir was estimated by adding the SPF hydrograph ordinates to the PMF hydrograph ordinates, after shifting the latter by three days, as presented in Figure 2.4S.3-8. This figure also includes the routed outflow hydrograph for the combined SPF and PMF event.
As shown in Figure 2.4S.3-8, the peak PMF inflow into Lake Travis at Mansfield Dam was estimated as 1,603,992 cfs (i.e. twice the peak SPF inflow of 801,996 cfs) (Reference 2.4S.3-8). The reservoir routing analysis showed that the peak PMF outflow at Mansfield Dam is about 944,138 cfs (see Figure 2.4S.3-8).
The HEC-1 routing with this very conservative estimate of the PMF inflow shows that Mansfield Dam would be overtopped. For the purpose of the PMF analysis, it was assumed that Mansfield Dam would not fail. The dam break analysis for Mansfield Dam is addressed in Subsection 2.4S.4. The peak outflow from Mansfield Dam obtained with the HEC-1 routing (944,138 cfs) exceeds all published values reviewed (see Table 2.4S.3-1) for the STP 3 & 4 and provides a conservative value for the peak outflow from Mansfield Dam.
Consequently, the PMF inflow and outflow hydrographs at Mansfield Dam developed as described above should only be used for the intended purpose of STP 3 & 4. These results are meant to provide conservative, i.e. high, estimates of maximum water levels in the vicinity of STP 3 & 4 site. These results should not be used for any other purpose; neither should any conclusions be drawn from these results regarding the potential flooding of areas downstream of Mansfield Dam.
Peak PMF Discharge at Bay City for Scenario 2: The peak PMF discharge at Bay City was calculated by adding the peak PMF outflow at Mansfield Dam (944,138 cfs) (see Figure 2.4S.3-8) to the peak of the 40% PMP hydrograph for the drainage area between Mansfield Dam and Bay City (303,277 cfs) (see Figure 2.4S.3-7) plus the base flow of 5200 cfs (see Subsection 2.4S.3.4.2.1). This approach provides a very conservative estimate for the peak PMF discharge at Bay City (1,252,615 cfs),
2.4S.3-14 Probable Maximum Flood (PMF) on Streams and Rivers Rev. 12
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because it does not account for the attenuation of the peak outflow from Mansfield Dam as the flood wave travels down the 290 mile long reach in the Lower Colorado River between Mansfield Dam and Bay City.
2.4S.3.4.2.3 PMF between Lake O.H. Ivie and Bay City for Scenario 3 For Scenario 3, the peak PMF for the Lower Colorado River basin area from Lake O.H. Ivie and Bay City was estimated by assuming that the SPF occurs over the same basin area three days before the PMF event and combining those flows with the base flow at Bay City. This scenario does not account for the storage effect of Lake Travis at Mansfield Dam or any other dam in the Lower Colorado River basin.
The PMF hydrograph for this scenario was estimated based on the SPF hydrograph that was developed at Wharton by the Halff study (Reference 2.4S.3-8) for unregulated flow conditions in Lower Colorado River Basin. The critical storm centering location for this SPF hydrograph at Wharton is found to be at subbasin SS-18 (see Vol. II-B, Chapter. 4, Table VI-7 of Reference 2.4S.3-8), which is located in the upper portion of the Lower Colorado River basin, as shown in Figure 2.4S.3-3. The SPF peak discharge at Wharton was estimated as 423,3215 cfs (Subsection 2.4S.3.4.1.4).
Estimation of PMF Hydrograph at Bay City: The SPF hydrograph at Wharton (with a peak discharge of 423,321 cfs) was used to estimate the SPF hydrograph at Bay City. The ordinates of SPF hydrograph at Wharton were multiplied by the ratio of the drainage area at Bay City (30,837 sq. mi) over the drainage area at Wharton (30,600 sq. mi) to estimate the SPF hydrograph at Bay City. The SPF peak discharge at Bay City was estimated to be about 426,000 cfs. The drainage areas at Wharton and Bay City were obtained from the Halff study (Vol. II-B, Chapter 4, Table IV-1 of Reference 2.4S.3-8). The required PMF hydrograph at Bay City for Scenario 3 was estimated by assuming that the PMF is equal to twice the SPF at Bay City. This assumption is based on guidelines in Engineering Manual EM 1110-2-1411 (Reference 2.4S.3-14). The PMF peak discharge at Bay City was estimated to be 853,200 cfs (see Figure 2.4S.3- 9).
Peak PMF Discharge at Bay City for Scenario 3: The PMF hydrograph developed for the Lower Colorado River basin from Lake O.H. Ivie to Bay City has a peak discharge of 853,200 cfs at Bay City (see Figure 2.4S.3-9) without the SPF event and base flow. As shown in Figure 2.4S.3-9, adding the SPF event with a peak discharge of 426,600 cfs over the same area, occurring three days before the PMF event and the base flow of 5,200 cfs at Bay (see Subsection 2.4S.3.4.2.1), produces a peak PMF at Bay City equal to 994,060 cfs (see Figure 2.4S.3-9).
2.4S.3.4.3 Most Critical PMF Scenario at Bay City The analyses discussed in Subsections 2.4S.3.4.2.1, 2.4S.3.4.2.2, and 2.4S.3.4.2.3 show that Scenario 1 produces the highest peak PMF at Bay City (see Table 2.4S.4.3-
5 The value of 423,321 cfs for the peak of the SPF peak at Wharton was extracted from the computer files obtained from Halff Associates Inc. In the report documenting this work (Reference 2.4S.3-8) this peak inflow was rounded to 425,000 cfs (Reference 2.4S.3-8, Vol. II-B, Chapter. 4, Table VI-7 of).
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6). The highest flood peak at Bay City is caused by the PMP for the drainage area between Mansfield Dam and the Bay City combined with an antecedent storm equal to 40% of the PMP occurring over the same drainage area, the flow release of 90,000 cfs from Mansfield Dam, and the base flow of 5200 cfs. Therefore, the peak flow of 1,397,432 cfs for Scenario 1 is used as the most critical PMF scenario to evaluate potential flooding at the STP 3 & 4 site.
2.4S.3.5 Water Level Determinations The maximum still water surface elevation at the STP 3 & 4 site for the peak PMF discharge of 1,397,432 cfs was calculated using the United States Army Corps of Engineer’s HEC-RAS hydraulic model, Version 3.1.3 (Reference 2.4S.3-18). The HEC-RAS model for the STP 3 & 4 site was developed on the basis of topographic data and hydraulic characteristics such as Manning’s roughness coefficients that were established for the Halff’s flood damage evaluation study (Reference 2.4S.3- 8).
2.4S.3.5.1 Halff HEC-RAS Hydraulic Model - Bay City to Matagorda Bay The Halff HEC-RAS model (from Bay City to Matagorda Bay), that was developed for the Halff’s flood damage evaluation study used the most recent channel and floodplain topographic information obtained from LCRA and the United States Army Corps of Engineers (USACOE). The required channel topographic data were field-surveyed and provided by USACOE. The floodplain topographic data obtained from LCRA included aerial digital ortho-photographs, digital contour maps (2 foot intervals), and USGS 30-m National Elevation Dataset (NED) Digital Elevation Model (DEM) data. The 30-m DEM data were used only to fill a 0.5 mile buffer zone area outside the 500- year floodplain that was mapped using the aerial digital data (Vol.1, pg. 20 of Reference 2.4S.3-8).
The Halff HEC-RAS model from Bay City to Matagorda Bay covers approximately a reach length of 24 miles and includes two bridge crossings, one at the Missouri Pacific Railroad (RS 1350+15.3) and another at the FM 521 roadway (RS 843+40.0). The upstream-most cross-section in the Halff model is located at the Bay City USGS gauging station (RS 1665+21.6). The downstream-most cross-section (RS 383+64.5) in the model is located about 4600 ft upstream of the intersection of Lower Colorado River and the Intra-Coastal Waterway (RS 337+90) (see Vol. II-C, Chapter 6, Table I- 1 of Reference 2.4S.3). Table2.4S.4.3-7 lists the key cross-sections in the Halff HEC- RAS model, which include two bridge crossings and 68 channel cross-sections.
The initial Manning’s roughness coefficients used in the Halff HEC-RAS model were estimated from the USGS National Land Cover Dataset coverage and then adjusted using aerial photographs (see Vol. II-C, Chapter 6, Table III-2 of Reference 2.4S.3-8). During the model calibration by Halff Associates, the roughness coefficients were subsequently adjusted in the model to match historical flood levels using USGS gauge data. The cross sections, gauges, and storms used for adjustment are available in Table IV-1 of Reference 2.4S.3-8 (Vol. II-A, Ch. 6, pg. 21). Calibration values for steady HEC-RAS runs were based on a six-stage "clean-up" procedure discussed on pg. 18-19 of Reference 2.4S.3-8 (Vol. II-C, Ch. 6). Calibration for the unsteady HEC- RAS runs are described on pg. 20 of Reference 2.4S.3-8 (Vol. II-C, Ch. 6). Validation
2.4S.3-16 Probable Maximum Flood (PMF) on Streams and Rivers Rev. 12
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of the calibration results are shown in Attachment A of Vol. II-C, Chapter 6 of Reference 2.4S.3-8. The calibrated Manning’s roughness coefficients used in model are 0.035 for the river channel, 0.045-0.05 for the overbank, and 0.085-0.095 for the floodplain.
2.4S.3.5.2 Extension of Cross-sections for the PMF Event A review of the geometry data used in the Halff HEC-RAS model showed that the cross-sections need to be extended to more accurately reflect the potential increase in the width of the floodplain during the passage of a PMF event. The cross-section data used in Halff’s HEC-RAS model was therefore extended, as shown in Figure 2.4S.3- 10, to cover a larger floodplain area between the most downstream cross-section (RS 383+64.5) and the STP 3 & 4 site (RS 964+99.7). Because the stretch of the Colorado River from the site to Matagorda Bay is in a sub-critical flow regime, it is not necessary to extend the cross-sections any further upstream from the STP 3 & 4 site because the flood elevation at the site depends only on conditions downstream from the STP 3 & 4 site.
A total of 32 cross-sections were extended (between RS 383+64.5 and RS 964+99.7) for a distance up to about 19 miles towards the east of the Lower Colorado River to near Caney Creek. The source maps used for the extension of these cross sections were high-resolution digital raster graphic (DRG) scans of the USGS 7.5-minute quadrangles6. To be conservative, these cross-sections were not extended to the west of the Colorado River.
2.4S.3.5.3 HEC-RAS Hydraulic Model for STP 3 & 4 The HEC-RAS hydraulic model (Version 3.1.3) for the STP 3 & 4 site was developed using the above extended cross-sections (from RS 383+64.5 to RS 964+99.7) and Manning’s roughness coefficients adjusted for PMF flow conditions. As the flow depth increases, the flow encounters larger size obstructions, e.g. shrubs, trees, etc, which effectively increase the roughness of the floodplain. For this purpose the calibrated Manning’s roughness coefficients used in the Halff HEC-RAS model (see Subsection 2.4S.3.5.1) were increased by 20% for the postulated PMF flow condition to provide a conservative estimate of the maximum stream flooding elevation at the site. The Manning's roughness coefficients that were increased by 20% for the PMF had values of 0.042 for the river channel, 0.054-0.06 for the overbank, and 0.102-0.114 for the floodplain. Since the Manning's roughness coefficients cannot be determined a priori to a PMF event occurring in the Lower Colorado River, this increase in the roughness coefficient was based on experimental results of flooding in meandering streams (Reference 28), and from roughness coefficients for the river channel, overbank, and floodplain areas listed in Table 3-1 of Reference 2.4S.3-18.
The HEC-RAS model developed for the STP 3 & 4 covers an approximate reach length of 11 miles and includes a bridge crossing at the FM 521 (RS 843+40.0). Incorporation of this bridge crossing in the model gives a conservative (i.e. higher) estimate for the
6 The vertical datum for the USGS 7.5-minute quadrangles is referenced to NGVD29. This datum is adjusted to match NAVD88 that was used as the vertical datum for the Halff’s cross-sections.
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maximum flood level. The upstream-most cross-section in this model is located at RS 964+99.7 and the downstream-most cross-section is at RS 383+64.5.
2.4S.3.5.3.1 Model Boundary Conditions Under PMF flow conditions, the water level in the river at the downstream-most cross- section (RS 383+64.5) is not controlled by tidal effects. From 1961 to 2001, the highest water level recorded for National Oceanic and Atmospheric Administration (NOAA) Station #8772440 at Freeport is 4.95 feet above mean sea level (MSL) (Reference 2.4S.3-27). Therefore, normal depth for an estimated channel slope of 0.0001 is the appropriate boundary condition to use at the downstream-most cross-section of the model that is located approximately 7.3 mile upstream from the shoreline of the Gulf of Mexico (see Table 2.4S.4.3-7).
Using the HEC-RAS model developed for the STP 3 & 4 site, the normal depth at the downstream boundary (RS 383+64.5) was estimated to be equal to 17.5 ft NAVD88 for the peak PMF discharge of 1,397,432 cfs (see Figure 2.4S.3-11) with a steady state model simulation. This calculation was made using Manning’s n values equal to 1.2 times those used in the Halff HEC-RAS model (see Subsection 2.4S.3.5.1) to provide a conservative upper bound flood level at the site as a result of a PMF event.
Using the same Manning’s n values as those used in the Halff HEC-RAS model (see Subsection 2.4S.3.5.1), the normal depth at the downstream boundary (RS 383+64.5) was estimated to be equal to 16.2 ft NAVD88 for the peak PMF discharge of 1,397,432 cfs (see Figure 2.4S.3-12).
2.4S.3.5.3.2 PMF Still Water Surface Elevation at STP 3 & 4 As shown in Figure 2.4S.3-11, the maximum PMF still water surface elevation at the STP 3 & 4 site (RS 891+46.0) for the normal depth boundary condition was estimated to be equal to 26.1 ft NAVD88 (26.3 ft NGVD29), which is lower than the design plant grade elevation of 35 ft NGVD29 for safety related structures. The PMF water level of 26.1 ft NAVD88 (26.3 ft NGVD29) at STP 3 & 4 was obtained using conservative Manning’s n values equal to 1.2 times those used in the original Halff model.
The PMF still water surface profile obtained using the same Manning’s n values as those used in the Halff model is shown in Figure 2.4S.3-12. In this case, the maximum PMF still water surface elevation at the STP 3 & 4 site (RS 891+46.0) was estimated as 24.8 ft NAVD88 (25.0 ft NGVD29).
PMF water levels at two selected cross-sections: the downstream boundary (RS 383+64.5) and the STP 3 & 4 site (RS 891+46.0) are shown in Figure 2.4S.3-13 (with Manning’s n values equal to 1.2 times in the Halff model) and Figure 2.4S.3-14 (with same Manning’s n values used in the Halff model).
2.4S.3.6 Coincident Wind Wave Activity The flooding resulting from dam failures upstream of the STP 3 & 4 site was found to be more critical than that resulting from the PMF. For example, the calculated maximum still water level at the STP site due to a domino-type failure of the upstream
2.4S.3-18 Probable Maximum Flood (PMF) on Streams and Rivers Rev. 12
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dams would be at 28.4 ft NAVD88 (28.6 ft NGVD29), (Subsection 2.4S.4.2.15), which is about 2.3 ft higher than the calculated maximum still water level of 26.1 ft NAVD88 (26.3 ft NGVD29) resulting from the PMF. Coincident wind wave activity was therefore considered for flooding resulting from dam failures only (Subsection 2.4S.4.3.1).
2.4S.3.7 References 2.4S.3-1 STPEGS Updated Final Safety Analysis Report (UFSAR) for Units 1 & 2, Revision 13, May 1, 2006.
2.4S.3-2 “Probable Maximum Flood, Marshall Ford Dam, Lower Colorado River Project, Texas,” United States Department of Interior, Bureau of Reclamation, November 1985.
2.4S.3-3 “Mansfield Dam Comprehensive Facility Review, Highland Lakes Dams, Lower Colorado River Authority, ” United States Department of Interior, Bureau of Reclamation, Technical Service Center, Denver, Colorado, March 2003.
2.4S.3-4 USBR official website. Available at http://www.usbr.gov/dataweb/dams/tx01087.htm, accessed on February 20, 2007.
2.4S.3-5 “SEED Analysis Report - Marshall Ford Dam,” ATC Engineering Consultants Inc. (ECI), prepared for the United States Department of Interior, Bureau of Reclamation, Colorado River Project, July 1989.
2.4S.3-6 “Civil Engineering Report of Intermediate Examination of Marshall Ford Dam, Colorado River Authority, Texas,” Goodson & Associates Inc., December 1990.
2.4S.3-7 “Phase II – Dam Safety Evaluation Project, Task Order B, Volume I,” prepared for the Lower Colorado River Authority, Freese & Nichols, Inc., August 1992.
2.4S.3-8 “Colorado River Flood Damage Evaluation Project – Phase I,” Volume I and Volume II, prepared for the Lower Colorado River Authority and Fort Worth District Corps of Engineers, Halff Associates, Inc, July 2002.
2.4S.3-9 “Seasonal Variation of the Probable Maximum Precipitation, East of the 105th Meridian for Area from 10 to 100 Square Miles and Durations of 6, 12, 24, and 48 hours,” Hydrometeorological Report No. 33, United States Weather Bureau, 1956.
2.4S.3-10 “Probable Maximum Precipitation Estimates, United States East of the 105th Meridian,” Hydrometeorological Report No. 51, United States Department of Commerce, National Oceanic and Atmospheric Administration (NOAA), June 1978.
Probable Maximum Flood (PMF) on Streams and Rivers 2.4S.3-19 Rev. 12
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2.4S.3-11 “Application of Probable Maximum Precipitation Estimates, United States East of the 105th Meridian,” Hydrometeorological Report No. 52, United States Department of Commerce, National Oceanic and Atmospheric Administration (NOAA), August 1982.
2.4S.3-12 “Engineering Guidelines for the Evaluation of Hydropower Projects, Determination of the Probable Maximum Flood,” Federal Energy Regulation Commission (FERC), September 2001.
2.4S.3-13 “Determining Design Basis Flooding at Power Reactor Sites,” ANSI/ANS- 2.8-1992, American Nuclear Society, July 1992.
2.4S.3-14 “Standard Project Flood Determination,” Engineering Manual 1110-2-1411, United States Army Corps of Engineers, March 1965.
2.4S.3-15 “HEC-1 Flood Hydrograph Package, User’s Manual, Version 4.0,” United States Army Corps of Engineers, September 1990.
2.4S.3-16 “Water and Power Resources Service - Project Data,” United States Department of Interior Bureau of Reclamation, A Water Resources Technical Publication, 1981.
2.4S.3-17 “Hydrologic Engineering Center - Hydrologic Modeling System, HEC-HMS Model, Version 2.2.2,” United States Army Corps of Engineers, May 2003.
2.4S.3-18 “Hydrologic Engineering Center - River Analysis System, HEC-RAS Model, Version 3.1.3,” United States Army Corps of Engineers, May 2005.
2.4S.3-19 “Technical Memorandum NWS HYDRO-35,” National Oceanic and Atmospheric Administration (NOAA), June 1977.
2.4S.3-20 “Technical Paper No. 40, Rainfall Frequency Atlas of the United States for Durations from 30 Minutes to 24 Hours and Return Periods from 1 to 100 Years,” United States Department of Commerce, Weather Bureau, May 1964.
2.4S.3-21 “Technical Paper No. 49, Two- to Ten-Day Precipitation for Return Periods of 2 to 100 Years in the Contiguous United States,” United States Department of Commerce, Weather Bureau, May 1964.
2.4S.3-22 “Discharge Coefficients for Irregular Overfall Spillways, Engineering Monograph No. 9,” Bradley, J.N, United States Department of the Interior, Bureau of Reclamation, 1952.
2.4S.3-23 “2006 Region K Water Plan for the Lower Colorado Regional Water Planning Group,” Texas Water Development Board (TWDB), January 2006.
2.4S.3-20 Probable Maximum Flood (PMF) on Streams and Rivers Rev. 12
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2.4S.3-24 “Flood-Runoff Analysis,” Engineering Manual 1110-2-1417, United States Army Corps of Engineers, August 1994.
2.4S.3-25 “Engineering Data on Dams and Reservoirs in Texas,” Report 126, Part III, Texas Water Development Board (TWDB), February 1971.
2.4S.3-26 “Water Management Plan for the Lower Colorado River Basin,” Lower Colorado River Authority (LCRA), March 1999.
2.4S.3-27 "NOAA Tides and Currents", Station #8772440, Available at http://www.co- ops.nos.noaa.gov/data_menu.shtml?stn=8772440%20Freeport,%20TX&t ype=Datums, accessed May 23, 2008.
2.4S.3-28 Smith, C.D. 1992. Reliability of flood discharge estimates: Discussion. Canadian Journal of Civil Engineering 19: 1085-1087.
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Table 2.4S.3-1 PMF and SPF values at Mansfield Dam PMF SPF Hydrologic Study Inflow Outflow Inflow Outflow Reviewed (cfs) (cfs) (cfs) (cfs) UFSAR for STP 1 & 2 957,000 [1] 706,000 [1] - - (Reference 2.4S.3-1) USBR and Others 931,600 [1] 602,210 [1] - - (References 2.4S.3-2, 2.4S.3-3, 4, 2.4S.3-5, and 2.4S.3-6) Freese Nichols Inc. - 837,094 [1] - - (Reference 2.4S.3-7) Halff Associates Inc. - - 801,996 [2],[3] - (Reference 2.4S.3-8)
[1] Estimated based on HMR 52 (Reference 2.4S.3-11). [2] Estimated based on Engineering Manual 1110-2-1411 (Reference 2.4S.3-14). [3] The value of 801,996 cfs for the peak of the SPF peak inflow into Mansfield Dam was extracted from the computer files obtained from Halff Associates Inc. In the report documenting this work (Reference 2.4S.3-8) this peak inflow was rounded to 800,000 cfs (see Vol. II-B, Chapter. 4, Table VI-5 of Reference 2.4S.3-8).
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Table 2.4S.3-2 Drainage Areas, Unit Hydrograph Parameters, Rainfall Loss Rates, and PMP Depths for Subbasins from Mansfield Dam to Matagorda Bay
Snyder Snyder Initial Constant Sub- Drainage Percent Peaking Time Lag Rainfall Rainfall basin Area [1] Impervious Coefficient [2] Loss [3] Loss [3] PMP Depth Name (sq. mi.) [1] [1] (hours) (in) (in/hr) [4] (in) AL-16 25.2 21.12 0.7 1.22 0 0.05 39.8 AL-17 43.7 5.39 0.5 2.17 0 0.05 41.2 AL-18 1.4 9.56 0.5 0.71 0 0.05 43.1 AL-19 22.7 2.88 0.5 1.73 0 0.05 41.2 AL-20 9.2 2.08 0.5 1.04 0 0.05 42.4 AL-21 14.1 7.95 0.5 1.01 0 0.05 43.8 AL-22 8.7 10.69 0.5 1.04 0 0.05 44.1 AL-23 89.6 0.44 0.8 5.07 0 0.05 37.9 AL-24 17.8 0.00 0.8 2.59 0 0.05 41.9 AL-25 9.4 7.39 0.8 1.97 0 0.05 42.3 AL-26 3.1 8.46 0.5 0.98 0 0.05 44.3 AL-27 28.6 23.06 0.5 1.61 0 0.05 44.7 AL-28 1.9 27.99 0.5 0.80 0 0.05 46.5 AL-29 20.6 19.68 0.6 3.89 0 0.05 46.9 AL-30 51.6 12.44 0.7 3.19 0 0.05 43.3 AL-31 4.8 3.09 0.6 3.56 0 0.05 47.4 AL-32 14.0 16.05 0.6 3.86 0 0.05 47.6 AL-33 6.6 12.85 0.6 4.15 0 0.05 49.9 AL-34 104.6 0.33 0.7 3.62 0 0.05 34.7 AL-35 19.0 0.00 0.7 2.26 0 0.05 36.4 AL-36 43.7 0.94 0.8 3.70 0 0.05 36.2 AL-37 66.7 0.23 0.8 4.00 0 0.05 36.7 AL-38 89.7 3.91 0.8 4.64 0 0.05 41.7 AL-39 21.4 7.59 0.6 4.67 0 0.05 47.6 CC-01 6.3 6.12 0.6 3.71 0 0.05 51.0 CC-02 41.5 0.62 0.6 3.52 0 0.05 42.4 CC-03 33.8 6.51 0.6 4.50 0 0.05 48.6 CC-04 25.6 4.07 0.6 4.66 0 0.05 53.1 CC-05 55.0 0.86 0.6 5.53 0 0.05 48.8 CC-06 22.6 3.86 0.6 4.99 0 0.05 55.7 CC-07 163.7 0.61 0.6 7.76 0 0.05 44.5 CC-08 17.4 0.78 0.6 4.22 0 0.05 51.4
Probable Maximum Flood (PMF) on Streams and Rivers 2.4S.3-23 Rev. 12
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Table 2.4S.3-2 Drainage Areas, Unit Hydrograph Parameters, Rainfall Loss Rates, and PMP Depths for Subbasins from Mansfield Dam to Matagorda Bay (Continued)
Snyder Snyder Initial Constant Sub- Drainage Percent Peaking Time Lag Rainfall Rainfall basin Area [1] Impervious Coefficient [2] Loss [3] Loss [3] PMP Depth Name (sq. mi.) [1] [1] (hours) (in) (in/hr) [4] (in) CC-09 3.0 9.05 0.6 3.56 0 0.05 55.2 CC-10 62.6 0.69 0.6 4.82 0 0.05 43.3 CC-11 47.0 0.63 0.6 5.15 0 0.05 48.1 CC-12 52.2 4.79 0.6 4.76 0 0.05 50.2 CC-13 28.7 4.16 0.45 5.42 0 0.05 51.9 CC-14 39.6 0.58 0.45 6.66 0 0.05 46.7 CC-15 56.0 0.68 0.45 5.75 0 0.05 44.3 CC-16 34.8 0.80 0.45 5.22 0 0.05 50.2 CC-17 12.1 0.31 0.45 5.02 0 0.05 50.5 CC-18 137.5 0.52 0.45 7.08 0 0.05 43.5 CC-19 65.4 0.62 0.45 5.83 0 0.05 45.0 CC-20 5.5 1.03 0.45 4.66 0 0.05 50.5 CC-21 102.4 1.55 0.45 6.20 0 0.05 50.5 CC-22 41.8 3.91 0.3 4.65 0 0.05 48.1 CC-23 42.3 1.52 0.3 5.12 0 0.05 45.9 CC-24 17.4 2.94 0.3 4.43 0 0.05 46.0 CC-25 118.1 1.25 0.3 5.90 0 0.05 47.4 CC-26 38.7 3.65 0.3 4.78 0 0.05 45.7 CC-27 125.1 1.34 0.3 6.24 0 0.05 43.6 CC-28 28.1 2.85 0.3 4.35 0 0.05 44.3 CC-29 3.0 9.08 0.3 1.16 0 0.05 43.9 CC-30 91.6 1.04 0.9 11.10 0 0.05 41.4 CC-31 94.2 1.15 0.3 7.06 0 0.05 43.1 CC-32 103.2 5.63 0.3 5.51 0 0.05 43.1 CC-33 82.1 2.49 0.3 6.08 0 0.05 41.4 CC-34 78.6 2.2 0.3 6.50 0 0.05 39.0 CC-35 80.7 1.63 0.4 3.98 0 0.05 40.9 CC-36 95.9 1.11 0.4 4.33 0 0.05 40.7 CC-37 75.3 0.68 0.4 4.37 0 0.05 40.2 CC-38 63.4 1.12 0.3 5.93 0 0.05 38.8 LC-01 94.5 6.99 0.3 6.44 0 0.05 37.1 LC-02 110.8 3.75 0.3 6.57 0 0.05 36.7
2.4S.3-24 Probable Maximum Flood (PMF) on Streams and Rivers Rev. 12
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Table 2.4S.3-2 Drainage Areas, Unit Hydrograph Parameters, Rainfall Loss Rates, and PMP Depths for Subbasins from Mansfield Dam to Matagorda Bay (Continued)
Snyder Snyder Initial Constant Sub- Drainage Percent Peaking Time Lag Rainfall Rainfall basin Area [1] Impervious Coefficient [2] Loss [3] Loss [3] PMP Depth Name (sq. mi.) [1] [1] (hours) (in) (in/hr) [4] (in) LC-03 62.8 13.38 0.3 8.95 0 0.05 35.5 LC-04 63.2 8.35 0.3 6.50 0 0.05 34.2 LC-05 32.1 7.73 0.3 7.54 0 0.05 33.5 LC-06 29.7 10.44 0.3 5.72 0 0.05 32.8 LC-07 35.6 5.43 0.3 5.52 0 0.05 32.3 LC-08 29.3 4.40 0.3 5.63 0 0.05 32.9 LC-09 33.4 3.38 0.3 4.68 0 0.05 32.8 LC-10 20.4 11.78 0.3 5.27 0 0.05 31.9 LC-11 21.6 7.36 0.3 3.35 0 0.05 31.4 LC-12 50.3 4.59 0.3 4.28 0 0.05 31.9 LC-13 30.2 10.21 0.3 3.42 0 0.05 31.2 LC-14 31.0 7.63 0.5 3.50 0 0.05 30.9 LC-15 27.3 2.72 0.7 2.33 0 0.05 30.7 LC-16 38.4 7.07 0.7 1.94 0 0.05 30.4 LC-17 34.8 33.89 0.7 2.35 0 0.05 30.2 LC-18 2.6 60.91 0.7 1.09 0 0.05 30.0
[1] Drainage areas, percentage impervious values, and calibrated Snyder peaking coefficients are extracted from the Halff HEC-HMS model (Vol. II-B, Chapter. 4, Attachment B-1 of Reference 2.4S.3-8). [2] Snyder lag time values given here account for the non-linearity effect in the runoff process during a PMF event. The calibrated Snyder lag time parameters extracted from the Halff HEC- HMS model are decreased by 25% to obtain these values. [3] Initial rainfall loss and constant rainfall loss rate values are obtained from Reference 2.4S.3-12 for the PMF conditions. [4] Estimated PMP depths used for the PMF calculations at STP 3 & 4 site (see Subsection 2.4S.3.4.2.1).
Probable Maximum Flood (PMF) on Streams and Rivers 2.4S.3-25 Rev. 12
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Table 2.4S.3-3 10 sq. miles PMP Depth at Subbasin CC-06 Duration (hour) PMP Depth (inches) Remarks 6 31.0 Figure 18, HMR 51 12 37.5 Figure 19, HMR 51 24 44.8 Figure 20, HMR 51 48 50.0 Figure 21, HMR 51 72 53.1 Figure 22, HMR 51 96 55.7 Extrapolated
2.4S.3-26 Probable Maximum Flood (PMF) on Streams and Rivers Rev. 12
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Table 2.4S.3-4 Dam and Spillway Outlet Data for Lake Travis Reservoir
Elevation Length/or Reservoir Storage Description (ft) Diameter [3] (ft) (acre-ft) Low level outlet 540 24 102-in conduits 32,500 [1] Conservation pool 681 n/a 1,132,172 [1] Uncontrolled ogee spillway crest 714 700 clear opening 1,879,794 [1], [4] Dam crest (concrete section) 750 2710 3,125,683 [2], [4] Floodwall crest 754.1 4393 [5] 3,308,030 [2]
[1]Elevation vs. Storage data (from El. 540 ft to El. 714 ft NGVD29) are obtained from the Halff Reservoir Operation Model HEC-5 (see Vol. II-B, Chapter 5, Reference 2.4S.3-8). [2]Storage values are estimated by logarithmic extrapolation of elevation-storage data from El. 691 ft to El. 740 ft NGVD29 (see Table 2.4S.3-5). [3]Elevation, length, and diameter values are obtained from Halff (Reference 2.4S.3- 8), USBR (Reference 2.4S.3-16), and TWDB (Reference 2.4S.3- 25). [4]Reference 2.4S.3-5 states that at El. 714 ft NGVD29, the reservoir storage capacity is equal to 1,953,000 acre-ft and at El. 750 ft NGVD29, the storage capacity is equal to 2,893,800 acre- ft. [5]Floodwall length is set equal to the length of the concrete dam (i.e. 5093 ft – 700 ft), where 5093 ft is the total length of the dam section as per USBR (Reference 2.4S.3-16).
Probable Maximum Flood (PMF) on Streams and Rivers 2.4S.3-27 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.4S.3-5 Elevation-Storage Data for Lake Travis Reservoir at Mansfield Dam
Reservoir Water Surface Elevation Reservoir Storage Volume (in feet, NGVD29 Datum [3]) (acre-ft) 536 18,270 [1] 630 436,502 [1] 650 652,977 [1] 670 939,110 [1] 691 1,329,593 [1] 710 1,772,913 [1] 722 2,109,176 [1] 732 2,428,210 [1] 740 2,710,598 [1] 750 3,125,683 [2] 760 3,587,326 [2]
[1]Elevation vs. Storage data (from El. 536 ft to El. 740 ft NGVD29) are obtained from the Halff Reservoir Operation Model HEC-5 (see Vol. II-B, Chapter 5, Reference 2.4S.3-8). [2]Storage values are estimated by logarithmic extrapolation of elevation-storage data from El. 691 ft to El. 740 ft NGVD29. [3]At Lake Travis reservoir, NAVD88 ft = NGVD29 ft + 0.22 ft.
2.4S.3-28 Probable Maximum Flood (PMF) on Streams and Rivers Rev. 12
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Table 2.4S.3-6 Estimated Peak PMF at Bay City for STP 3 & 4
Description of the PMF Flow Scenario Peak PMF at Bay City (cfs) Scenario 1: PMF for the drainage area between Mansfield Dam and the 1,397,432 Bay City, combined with the flood hydrograph from an antecedent storm equal to 40% of the PMP occurring over the same drainage area, three days before the PMF, a flow release of 90,000 cfs from Mansfield Dam, and a base flow of 5200 cfs. Scenario 2: PMF inflow hydrograph to Mansfield Dam routed through 1,252,615 Lake Travis and combined with the flood hydrograph from a sequential storm equal to 40% of the PMP occurring over the drainage area (Mansfield Dam to Bay City), three days after the PMP storm upstream of Mansfield Dam and a base flow of 5200 cfs Scenario 3: PMF for the entire Lower Colorado River basin area between 994,060 Lake O.H. Ivie and Bay City combined with the flood hydrograph from an antecedent storm equal to the SPS over the same area, occurring three days before the PMF and a base flow of 5200 cfs.
Probable Maximum Flood (PMF) on Streams and Rivers 2.4S.3-29 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.4S.3-7 Location Description for Key Cross Sections in the HEC-RAS Model HEC-RAS Location Description Cross-section River Station River Station of Cross-section No. (feet) (miles) Bay City USGS Station 1 RS 1665+21.6 31.54 Bridge Missouri Pacific Railroad 16 RS 1350+15.3 25.57 STP 3 & 4 Site 43 RS 891+46.0 16.89 Bridge at FM 521 47 RS 843+40.0 15.97 4600 ft upstream from Intra-Coastal 70 RS 383+64.5 7.27 Waterway
2.4S.3-30 Probable Maximum Flood (PMF) on Streams and Rivers Rev. 12
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Figure 2.4S.3-1 General Location of STP 3 & 4 Site in the Lower Colorado River Basin
Probable Maximum Flood (PMF) on Streams and Rivers 2.4S.3-31 Rev. 12
STP 3 & 4 Final Safety Analysis Report (Modified from Reference 2.4S.3-8) from Reference (Modified Figure 2.4S.3-2a Drainage Delineation of Subbasins between Mansfield Dam and Matagoda Bay and Matagoda Dam Mansfield between of Subbasins Delineation Drainage Figure 2.4S.3-2a
2.4S.3-32 Probable Maximum Flood (PMF) on Streams and Rivers Rev. 12
STP 3 & 4 Final Safety Analysis Report (Modified from Reference 2.4S.3-8) from Reference (Modified Figure 2.4S.3-2b Drainage Delineation of Subbasins between Mansfield Dam and Matagoda Bay and Matagoda Dam Mansfield between of Subbasins Delineation Drainage Figure 2.4S.3-2b
Probable Maximum Flood (PMF) on Streams and Rivers 2.4S.3-33 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.4S.3-3 Lower Colorado River Basin from Lake O.H. Ivie to Matagorda Bay (Modified from Reference 2.4S.3-8) from Reference (Modified to Matagorda Bay O.H. Ivie Lake from River Basin Colorado Lower 2.4S.3-3 Figure
2.4S.3-34 Probable Maximum Flood (PMF) on Streams and Rivers Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.4S.3-4 Storm Orientation Pattern for Locations Upstream of Mansfield Dam (Modified from Reference 2.4S.3-8) from Reference (Modified Dam Mansfield Upstream of Locations for Pattern Storm Orientation 2.4S.3-4 Figure
Probable Maximum Flood (PMF) on Streams and Rivers 2.4S.3-35 Rev. 12
STP 3 & 4 Final Safety Analysis Report ream of Mansfield Dam (Modified from Reference 2.4S.3-8) Reference from Dam (Modified ream of Mansfield Figure 2.4S.3-5 Storm Orientation Pattern for Locations Downst for Locations Pattern Storm Orientation 2.4S.3-5 Figure
2.4S.3-36 Probable Maximum Flood (PMF) on Streams and Rivers Rev. 12
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96-hour PMP Hyetograph at Sub-basin CC-06
14
12
) 10
8
6
4 Rainfall Intensity (in/hr
2
0 1 4 7 1013161922252831343740434649525558616467707376798285889194 Time (hours)
Figure 2.4S.3-6 96-hour PMP Hyetograph for Subbasin CC-06
Probable Maximum Flood (PMF) on Streams and Rivers 2.4S.3-37 Rev. 12
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1,600,000 Peak PMF at Bay City for Scenario 1 = 1,397,432 cfs
1,400,000 Peak PMF(t+3) = 1,096,807 cfs
1,200,000 Flow for 40% PMP(t)
PMF(t+3) 1,000,000 Mansfield Dam Release + Base flow
Flow for 40% PMP(t) + PMF(t+3) + 800,000 Mansfield Dam Release + Base flow Flow (cfs) 600,000 Peak Flow for 40% PMP(t) = 303,277 cfs
Mansfield Dam Release + Base flow = 95,200 cfs 400,000
200,000
Note: Starting date 12/30 is arbitrarily chosen. 0 12/30 1/2 1/5 1/8 1/11 1/14 1/17 1/20 Date
Figure 2.4S.3-7 PMF Hydrograph at Bay City for Scenario 1
2.4S.3-38 Probable Maximum Flood (PMF) on Streams and Rivers Rev. 12
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2,000,000 Inflow Peak of SPF(t)+PMF(t+3) = 1,653,473 cfs Inflow Peak of SPF(t) = 801,996 cfs 1,800,000 Inflow Peak of PMF(t+3) = 1,603,992 cfs
1,600,000 Outflow Peak of SPF(t)+PMF(t+3) = 944,138 cfs 1,400,000 Notes: 1. Initial reservoir water level is set at El. 681 ft NGVD29. 1,200,000 2. Low level outlet gates (at El. 540 ft NGVD29) are set at open positions.
1,000,000
Flow (cfs) Flow 800,000 SPF(t) PMF(t+3) 600,000 SPF(t)+PMF(t+3) Inflow to Lake Travis 400,000 SPF(t)+PMF(t+3) Outflow from Lake Travis
200,000
Note: Starting date 12/30 is arbitrarily chosen. 0 12/31 1/3 1/6 1/9 1/12 1/15 1/18 1/21 Date
Figure 2.4S.3-8 Development of PMF Outflow Hydrograph at Lake Travis for Scenario 2
Probable Maximum Flood (PMF) on Streams and Rivers 2.4S.3-39 Rev. 12
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1,200,000 Peak PMF at Bay City for Scenario 3 = 994,060 cfs
1,000,000 Peak PMF(t+3) = 853,200 cfs
800,000
Peak SPF(t) = 426,600 cfs SPF(t) PMF(t+3) 600,000 Base flow
Flow (cfs) SPF(t) + PMF(t+3) + Base flow 400,000
Base flow = 5,200 cfs 200,000
Note: Starting date 12/30 is arbitrarily chosen. 0 12/30 1/2 1/5 1/8 1/11 1/14 1/17 1/20 1/23 Date
Figure 2.4S.3-9 PMF Hydrograph at Bay City for Scenario 3
2.4S.3-40 Probable Maximum Flood (PMF) on Streams and Rivers Rev. 12
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Figure 2.4S.3-10 Extended Cross sections – Most downstream section to STP 3 & 4 Site
Probable Maximum Flood (PMF) on Streams and Rivers 2.4S.3-41 Rev. 12
STP 3 & 4 Final Safety Analysis Report values equal to 1.2 times those used in the Halff model) used those 1.2 times equal to values n (Manning’s (Manning’s Figure 2.4S.3-11 PMF Elevation at STP 3 & 4 Site for Normal Depth Boundary Condition Depth Boundary for Normal at STP 3 & 4 Site PMF Elevation Figure 2.4S.3-11
2.4S.3-42 Probable Maximum Flood (PMF) on Streams and Rivers Rev. 12
STP 3 & 4 Final Safety Analysis Report values equal to those used in the Halff model) Halff in the used to those equal values n (Manning’s (Manning’s Figure 2.4S.3-12 PMF Elevation at STP 3 & 4 Site for Normal Depth Boundary Condition Depth Boundary for Normal at STP 3 & 4 Site PMF Elevation Figure 2.4S.3-12
Probable Maximum Flood (PMF) on Streams and Rivers 2.4S.3-43 Rev. 12
STP 3 & 4 Final Safety Analysis Report values equal to 1.2 times those used in the Halff model) used those 1.2 times equal to values n (Manning’s (Manning’s Figure 2.4S.3-13 PMF Water Levels at STP 3 & 4 Site (RS 891+46.0) and at Downstream Boundary (RS 383+64.5) Boundary at Downstream and Site (RS 891+46.0) at STP 3 & 4 Levels PMF Water 2.4S.3-13 Figure
2.4S.3-44 Probable Maximum Flood (PMF) on Streams and Rivers Rev. 12 STP 3 & 4 Final Safety Analysis Report values equal to those used in the Halff model) Halff in the used to those equal values n (Manning’s (Manning’s Figure 2.4S.3-14 PMF Water Levels at STP 3 & 4 Site (RS 891+46.0) and at Downstream Boundary (RS 383+64.5) Boundary at Downstream and Site (RS 891+46.0) at STP 3 & 4 Levels PMF Water 2.4S.3-14 Figure
Probable Maximum Flood (PMF) on Streams and Rivers 2.4S.3-45/46
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2.4S.4 Potential Dam Failures The following site-specific supplement addresses COL License Information Items 2.14 and 3.5.
This section addresses the SRP Section 2.4.4 Acceptance Criteria Limits from the reference Table 2.1-1, which states that the flood level from failure of existing and potential upstream or downstream water control structures will not exceed 30.5 cm (1.0 ft) below grade. The nominal plant grade for the safety facilities of STP 3 & 4 is 34.0 ft mean sea level (MSL) and the design entrance level slab elevation is 35.0 ft MSL. The design basis flood level at STP 3 & 4 based on the worst case dam failure scenario, the postulated MCR embankment breach, was conservatively established as 40.0 ft MSL, exceeding the reference ABWR DCD site parameter flood level criteria. The departure from the DCD site parameter flood level and the evaluation summary are documented in STP DEP T1 5.0-1. Subsection 2.4S.4 develops the flooding design basis for considering potential hazards to the safety-related facilities due to potential dam failures.
The STP 3 & 4 site is located on the west bank of the Colorado River in Matagorda County, Texas, about 10.5 river miles upstream of the Gulf Intracoastal Waterway (GIWW). There are a total of 68 dams with storage capacity in excess of 5000 acre- feet (AF) on the Colorado River and its tributaries upstream of the STP site. These dams and reservoirs are owned and operated by different entities including the Lower Colorado River Authority (LCRA), the U.S. Bureau of Reclamation (USBR), the Colorado River Municipal Water District (CRMWD), other local municipalities and utilities. Figures 2.4S.4-1(a) and 2.4S.4-1(b) show the locations of the 68 dams. Specific information of these dams that are relevant to the flood risk assessment of STP 3 & 4 is summarized in Table 2.4S.4-1, based on data collected primarily from the Texas Water Development Board (TWDB), Texas Commission for Environmental Quality (TCEQ), and LCRA. The six hydroelectric dams – Buchanan, Roy Inks, Alvin Wirtz, Max Starcke, Mansfield, and Tom Miller, owned and operated by LCRA are known as the Highland Lake dams.
In Texas, both private and public dams are monitored and regulated by TCEQ under the Dam Safety Program. Existing dams, as defined in Rule §299.1 Title 30 of the Texas Administrative Code (Reference 2.4S.4-1), are subject to periodic re-evaluation in consideration of continuing downstream development. Hydrologic criteria contained in Rule §299.14 of Title 30 (Table 3) on Hydrologic Criteria for Dams are the minimum acceptable spillway evaluation flood (SEF) for re-evaluating dam and spillway capacity for existing dams to determine whether upgrading is required. Similarly, on the structural considerations, evaluation of an existing dam includes, but is not limited to, visual inspections and evaluations of potential problems such as seepage, cracks, slides, conduit and control malfunctions, and other structural and maintenance deficiencies which could lead to failure of a structure.
Following the 1987 National Dam Safety Inspection Program recommendations of the Texas Water Commission, a predecessor agency of the TCEQ, to upgrade two of the Highland Lake dams due to unsafe condition, LCRA initiated a program to evaluate all six Highland Lake dams with respect to hydrologic, structural and geotechnical criteria.
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In 1990, LCRA began a 15-year plan of Dam Modernization Program to address the safety condition of five of the six dams. A 1992 dam safety evaluation study commissioned by LCRA (Reference 2.4S.4-2) indicates that Wirtz, Starcke, and Tom Miller Dams would be overtopped during a Probable Maximum Flood (PMF) event, and certain sections of Buchanan, Wirtz, and Tom Miller Dams could have instability problems during severe flood conditions. The concrete dam sections of Mansfield Dam, however, would be stable during the PMF. At the completion of LCRA’s Dam Modernization Program in January of 2005, substantial upgrade work had been undertaken at Buchanan, Inks, Wirtz, and Tom Miller Dams to address the unsafe conditions (Reference 2.4S.4-3). Upgrade at Mansfield Dam was considered not necessary as it is able to withstand the PMF without further reinforcement. Even in the event of failures of either Buchanan, Inks, Wirtz, or Starcke dams, Mansfield Dam would hold their flood volumes without overtopping (Reference 2.4S.4-4).
The UFSAR of STP 1 & 2 (Reference 2.4S.4-5) identifies two dam failure scenarios that are most critical to the flooding at the STP site. They are: (1) the breaching of the embankment of the onsite Main Cooling Reservoir (MCR); and (2) the postulated cascade failure of the major upstream dams on the Colorado River. These two scenarios also form the basis of the maximum flood level evaluation for STP 3 & 4 resulting from potential dam failures because the watershed and topographic conditions remain relatively unchanged since the preparation of the UFSAR for STP 1 & 2, and also because there are no new dams (including the previously proposed Columbus Bend Dam) planned for the Colorado River in the next 50 years, according to the 2007 State Water Plan (Reference 2.4S.3-6, also discussed in Subsection 2.4S.3.4.2) The dam failure scenarios and the postulated flood risk are discussed further in the following subsections.
2.4S.4.1 Dam Failure Permutations 2.4S.4.1.1 Failures of Upstream Dams on the Colorado River Of all the dams on the Colorado River upstream of the STP 3 & 4 site, Mansfield Dam would generate the most significant dam break flood risk on the site. Mansfield Dam has the largest dam height of 266.4 ft and the largest reservoir storage capacity of 3.3 million acre-feet (MAF), at top of the dam. Among all the dams upstream, Mansfield Dam is also closest to the site at about 305 river miles upstream of the STP 3 & 4 site. The next major dam upstream that could pose significant flood risk to the site is the Buchanan Dam located at about 402 river miles upstream of STP 3 & 4. It has a height of 145.5 ft and a top-of-dam storage capacity of 1.18 MAF. Further upstream, the Simon Freese Dam, with a height of 148 ft and a top-of-dam storage capacity of 1.47 MAF, and the Twin Buttes Dam, with a height of 134 ft and top-of-dam storage capacity of 1.29 MAF are considered to have major, though not as significant, contribution to the flood risk at the STP site. They are located at about 199 miles and 290 miles, respectively, upstream of Buchanan Dam.
There are two failure permutations postulated of the upstream dams:
Scenario No. 1 – Simultaneous failure of all upstream dams induced by a seismic event. The failure is to occur coincidentally with a 2-year design wind event and a
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500-year flood or a one-half probable maximum flood (PMF) per American National Standard ANSI/ANS-2.8 (Reference 2.4S.4-7).
Scenario No. 2 – Domino-type failure of upstream dams with the same coincidental wind and flood events as in Scenario No. 1. It is postulated that the upstream-most dam(s) would fail first, thereby releasing a dam break flood wave (or waves) that propagates downstream and triggers the failure of the downstream dams one after another in a cascading manner. It is assumed that the 56 dams on the Colorado River and its tributaries upstream of Buchanan Dam (with top-of-dam capacity over 5000 AF) would fail in such a manner that their flood flow, expressed in terms of their respective top-of-dam storage volumes, would arrive at Lake Buchanan at approximately the same time, triggering the failure of Buchanan Dam. The dam break flood flow from Buchanan Dam would then propagate downstream to Lake Travis, overtopping Mansfield Dam and causing it to fail. The dam break flood from Mansfield Dam then propagates downstream to the STP 3 & 4 site. The failure is to occur coincidentally with a 2-year design wind event and a 500-year flood or a one-half probable maximum flood (PMF) per American National Standard ANSI/ANS-2.8 (Reference 2.4S.4-7).
Three upstream dams, Inks, Wirtz, and Starcke, located between Buchanan and Mansfield Dams, and two other upstream dams, Tom Miller and Longhorn Dams, located at 20 miles and 27 miles downstream of Mansfield Dam, were not included in the dam break analysis as their dam heights and potential flood volumes would have insignificant impact on the flood risk as compared to Mansfield Dam or Buchanan Dam.
There are five “off-channel” dams located on the tributaries of the Colorado River between Mansfield Dam and the STP site. They are: Decker Creek Dam (Lake Long), Bastrop Dam, Cummins Creek WS SCS Site 1 Dam, Cedar Creek Dam (Fayette Reservoir), and Eagle Lake Dam. These off-channel storage dams were also assumed to have no effect on the maximum dam break flood level at the STP 3 & 4 site, as compared to the major dams on the main stem of the Colorado River.
Of these two permutations, Scenario No. 2 would generate the most critical flood level at STP 3 & 4 because of the deliberate alignment of the travel and arrival of the dam breach flood volumes and flood peaks from the major upstream dams. Consequently, only the flood risk resulting from Scenario No. 2 was further evaluated.
Upstream dam failures induced by hydrologic causes such as probable maximum flood (PMF) will not be the controlling scenario in the evaluation of the maximum flood risk at the STP site. This is because the large dams with high hazard potential, such as O.C. Fischer, Simon Freese, Buchanan and Mansfield Dams, as listed in Table 2.4S.1-1, were either designed or have been upgraded to accommodate and sustain their respective PMFs in accordance with the hydrologic criteria for dams as defined in Rule 299.14 Title 30 of the Texas Administrative Code (Reference 2.4S.4-1). Mansfield Dam, in particular, would be able to hold the dam break flood volumes of either Buchanan, Wirtz, or Starcke Dams. Besides, the assumption that a domino-type dam failure of the 56 dams upstream of Buchanan with an aggregated top-of-dam storage volume of 6.87 MAF all arriving at Buchanan at about the same time is highly
Potential Dam Failures 2.4S.4-3 Rev. 12
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conservative and would have bounded the potential flood risk caused by hydrological dam failures.
2.4S.4.1.2 Postulated Failure of the Main Cooling Reservoir The MCR is enclosed by a rolled-earthen embankment, rising an average of 40 ft above the natural ground surface south of the plant site. The interior reservoir side slopes of the MCR embankment are lined with 2 feet thick soil cement. The centerline of the north embankment is approximately 2340 ft south of the centerline of the reactor buildings of STP 3 & 4. Site grade near the northern embankment is in the range of El. 27 ft MSL to El. 29 ft MSL, and the top of the embankment is at about El. 65.75 ft MSL. Normal maximum operating level of the reservoir is at El. 49.0 ft MSL, which is about 20 to 22 ft higher than the site grade near the northern embankment. Postulated failure mechanisms of the earth embankment include excessive seepage from piping through the foundations of the embankment, seismic activity leading to potential liquefaction of the foundation soils, and erosion of the embankment due to overtopping from flood or wind-wave events.
As discussed in the STP 1 & 2 UFSAR (Reference 2.4S.4-5), failure of the MCR embankment due to any of these probable mechanisms is not considered a credible event. Nevertheless, it is conceivable that a failure of the internal drainage system within the MCR embankment could saturate the embankment and allow seepage through it, which could then initiate a piping failure. Therefore, a piping failure of the MCR embankment was investigated and analyzed.
The northern MCR embankment, near the proposed circulating water intake and discharge pipeline, is the most critical location for piping failure because it is closest to, and inline with, Units 3 and 4. Two breach locations were considered for the analysis, one immediately east and one immediately west of the circulating water pipeline. Further discussion of breach parameter selection is presented in Subsection 2.4S.4.2.2.2.2.
2.4S.4.1.3 Potential for Landslide and Waterborne Missiles The potential for major scale landslide, and hence blockage of streams on the Lower Colorado River in the vicinity of the STP site, is highly improbable due to the flat terrain. This is consistent with the conclusion of the UFSAR for STP 1 & 2 (Reference 2.4S.4-5). According to the investigation, there is no threat posed to the STP site due to surge from bank material sliding into the Lower Colorado River.
The potential for waterborne missiles reaching the STP site due to upstream dam failure is not considered to be critical because the site is located in the flood plain of the Lower Colorado River where the flood flow velocities are in general substantially lower than that in the main channel. Although there is a potential for waterborne missiles due to the MCR embankment breach, these missiles are not considered to be critical to the design of the safety related structures compared to tornado missiles. The static and dynamic effects of the MCR embankment breach on the plant structures are discussed in Section 3.4.
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2.4S.4.2 Unsteady Flow Analysis of Potential Dam Failures 2.4S.4.2.1 Colorado River Dams The dams on the Colorado River are discussed in Subsection 2.4S.4.1. Table 2.4S.4-1 lists the height, length, top-of-dam storage capacity, type, and year of completion of the 68 dams with a top-of-dam storage capacity larger than 5000 AF each. Of these 68 dams, Mansfield Dam, Buchanan Dam and 56 other dams upstream of Buchanan Dam were selected for inclusion in the dam break analysis. Dams with less than 5000 AF storage capacity, i.e., less than 0.2% of that of Mansfield Dam, were excluded from further evaluation as the impact of their potential breaching on the flood risk at the site would be minimal. The top-of-dam storage volume of Mansfield Dam is about 3.3 MAF, estimated from the elevation-storage capacity curves given in Reference 2.4S.4-8. Similarly, the top-of-dam storage volume of Buchanan Dam is estimated to be about 1.18 MAF. The combined top-of-dam-storage volume of the 56 dams upstream of Buchanan Dam is 6.87 MAF.
2.4S.4.2.1.1 Conceptual Unsteady Flow Analytical Model The dam breach option of the USACE River Analysis System computer program (HEC-RAS) Version 3.1.3 (Reference 2.4S.4-9) was used to simulate the dam breach flood waves, which were then routed downstream to the STP 3 & 4, using the unsteady flow option of the program.
In the conceptual dam break flood model, the 56 dams upstream of Buchanan Dam would fail in a domino manner, with their combined top-of-dam storage capacity, totaling 6.87 MAF, arriving at Buchanan Dam at approximately the same time. As the flood level at Buchanan Dam rises to about 3 ft over the dam crest elevation of 1025.35 ft MSL, the dam would fail, thereby releasing the flood storage of Buchanan Dam plus the combined flood volumes from the 56 upstream dams. In accordance with the combined events requirements stipulated in the American National Standard ANSI/ANS-2.8 (Reference 2.4S.4-7), the evaluation of potential flood risks as a result of non-hydrologic dam break failures should also consider a coincidental event equal to a 500-year flood or one-half probable maximum flood (PMF), whichever is less. In this analysis, a constant flood flow of 500,000 cfs, slightly higher than the peak Standard Project Flood (SPF) inflow at Buchanan Dam and the 500-year flood peak inflow at Mansfield Dam, was conservatively used to represent the coincidental flow. The SPF and 500-year flood flow at several locations on the Colorado River are listed in Table 2.4S.4-2. They were estimated by Halff Associates, Inc. as part of the Lower Colorado River flood damage evaluation project conducted for LCRA and Fort Worth District Army Corps of Engineer (Reference 2.4S.4-10). The 500,000 cfs coincidental flow was applied to the entire model reach from Buchanan Dam to the downstream boundary at 4600 ft (0.9 river miles) upstream of the Gulf Intracoastal Waterway.
The flood wave from the breaching of Buchanan Dam would propagate down to the 266.4-ft high Mansfield Dam, with a crest elevation at 754.1 ft MSL and a top-of-dam storage capacity of 3.30 MAF. (In 1941, a 4-ft parapet wall was added to the dam crest raising its elevation from 750.1 ft MSL to 754.1 ft MSL to provide additional flood storage capacity.) Mansfield Dam was postulated to fail when it was overtopped by 3
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ft at El. 757.1 ft MSL. The three dams located between Buchanan and Mansfield Dams: Roy Inks, Alvin Wirtz, and Max Starcke Dams, have a combined storage of about 298,300 AF. These dams were not assumed to fail in the dam break model because their combined total storage amounts to only about 9% of the total dam break flood volume at Mansfield. The SPF flood hydrographs from 19 tributaries between Buchanan and Mansfield Dams as estimated by Halff Associates, Inc. in the flood damage evaluation study (Reference 2.4S.4-10) were included as tributary inflows to this reach. The tributary inflows together with the dam break flood wave from Mansfield Dam were then routed to the STP 3 & 4 site in the HEC-RAS model.
2.4S.4.2.1.2 Physical Dam Data and Estimates of Breached Sections Buchanan Dam, located at about 402 river miles upstream of STP 3 & 4, is 10,987 ft in length. It has two separate multiple concrete arch sections as well as a number of gravity sections (Reference 2.4S.4-8). The main dam section consists of 29 concrete arches, each of 70 ft in width and 145.5 ft in height. The total length of this multiple concrete arch section is 2030 ft and it occupies the deepest part of the river channel. To the right (looking downstream) is another shorter multiple concrete arch section of 805 ft in length, consisting of 23 arches of 35 ft wide each. Following the guidelines from Federal Energy Regulatory Commission (FERC) on dam break analysis (Reference 2.4S.4-11), 15 of the 29 larger arches (70 ft wide each) and 12 of the 23 smaller arches (35 ft wide each) were assumed to breach in the simulation. The breach section in the model was represented by a vertical section with a total width of 1470 ft and extending from the top of the dam to the bottom. The time to complete the breach was assumed to be 0.1 hour, based on the guidelines from FERC for the estimation of the dam breach parameter (Reference 2.4S.4-11). The model cross- section at Buchanan Dam is shown in Figure 2.4S.4-2.
Mansfield Dam, at about 305 river miles upstream of STP 3 & 4, has a 2710 ft long, 266.4 ft high concrete gravity section occupying the main river channel, and a 4380 ft long earthen rockfill saddle section with a maximum height of about 150 ft on the left side (looking downstream) (Reference 2.4S.4-8). The total storage capacity is 3.13 MAF at the dam crest elevation of 750.1 ft MSL. With the installation of the 4-ft parapet wall in 1941, the storage capacity increased to 3.30 MAF. Following the FERC guidelines (Reference 2.4S.4-11), about half of the 2710 ft concrete gravity section was postulated to fail when overtopped by 3 ft, resulting in a 1360 ft wide vertical breached section from top to bottom. The time to complete the breach was also assumed to be 0.1 hour. The model cross-section for Mansfield Dam is shown in Figure 2.4S.4-3.
Table 2.4S.4-3 lists the dam breach characteristics used to model the failure of these two dams.
2.4S.4.2.1.3 Channel Geometry The channel geometry in the HEC-RAS dam break model was adopted from the river cross-sectional data of Halff’s flood damage evaluation study for the Lower Colorado River (Reference 2.4S.4-10 and discussed in Subsection 2.4S.4.3). The Halff model has a total model reach length of 474 river miles represented by 1048 cross-sections
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from Texas Highway 190 upstream of Buchanan Dam, to a section at 4600 ft (0.9 river miles) upstream of the Gulf Intracoastal Waterway just north of Matagorda Bay. The HEC-RAS dam break model developed for STP 3 & 4 has a shorter river reach of 414 miles starting from Buchanan Dam on the upstream end and was represented by a total of 793 model cross-sections. All bridge crossings specified in the Halff model were removed because they were assumed to be washed away during the dam break event. In addition, all ineffective flow areas as well as levees specified in the Halff model were also removed, when deemed appropriate. The locations of these cross- sections are shown in Figure 2.4S.4-4. The elevations of each of the cross-sections were referenced to the North America Vertical Datum 1988 (NAVD 88) in the Halff study. The HEC-RAS dam break model runs were also conducted in NAVD 88 datum. However, the flood level predictions were converted to MSL (or NGVD 29) for comparison with the STP plant grades.
Because the top-of-dam storage at Buchanan Dam was estimated to be 1.18 MAF, while the aggregated total top-of-dam storage of the 56 selected dams upstream of Buchanan Dam was estimated to be 6.87 MAF, it would not be possible for Buchanan Dam to accommodate the entire dam break flood volume from the breaching of these upstream dams. In order to properly account for the residual flows that could still arrive at and propagate downstream of Buchanan Dam after its failure, new model cross sections were introduced upstream of Buchanan Dam to extend the model reach by 36 miles to approximate the additional volume required to accommodate the combined dam break flood flow of 6.87 MAF from the dams upstream. The upstream reach extension consists of 37 rectangular cross sections 16,030-ft wide with a bottom elevation at 915.8 ft MSL. The cross-sectional width of 16,030 ft is similar to those of the three cross-sections behind Buchanan Dam in the Halff model (Reference 2.4S.4-10). The total flood volume in the model simulation would be over 8.0 MAF behind Buchanan Dam when it breaches at 3 ft above dam crest.
The primary objectives of the Halff study are for flood damage evaluations of the Lower Colorado River and therefore the model predictions were conducted for flood events up to the SPF. During extreme floods, inter-basin spillage could occur. Flood flow from the Colorado River could overspill into its neighboring sub-basins, such as Tres Palacios River to the west and San Bernard River and Peyton Creek to the east. In the flood of 1913, floodwaters from the Colorado River sub-basin overflowed into Caney Creek sub-basin to the east of the Colorado River near Wharton. With predictably higher flood discharges during the postulated dam failure scenario, the channel cross sections of the Halff study need to be extended beyond their limits to more accurately reflect the additional floodplain areas that would be inundated during the passage of the dam break flood waves. As HEC-RAS would automatically assume a vertical wall at the pre-set boundaries of the flood channel or floodplain, the extension could mitigate potentially unrealistic flood levels as a result of artificial limitation on the cross-sectional geometries imposed by the model setup. This can have a significant impact on the predicted flood peak in the lower reach of the river near the STP 3 & 4 site, where the drainage divides between sub-basins are relatively low in elevation.
A comparison was made between the simulated water levels from the initial dam break runs and the elevations of the drainage divides to determine the approximate location
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where inter-basin spillage would occur. It was found that inter-basin spillage could occur near Garwood. Therefore, about 1.9-mile extension was added to the Halff model cross sections on each side starting from near Garwood. The width of the extension on each side was gradually increased to about 9.5 miles near Wharton down the river. Because the topography is, in general, higher west of the Colorado River towards the Palacio River sub-basin, the cross-sectional extensions in the downstream reach shifted eastward towards the San Bernard River and the Peyton Creek sub- basins. Eventually, near the STP 3 & 4 site, the river cross-sections were extended towards the east for some 17 miles. Typical model cross-sections at four locations on the model river reach including the extended sections are shown in Figures 2.4S.4-5 to 2.4S.4-8.
The USGS 30-m National Elevation Dataset (NED) digital elevation model data used to establish the cross-sectional extensions was referenced to MSL (or NGVD 1929), while the Halff model was referenced to NAVD 88. As the difference between these two datum references for this reach of the Lower Colorado River is less than 0.3 ft, no corrections to the datum, except for 32 sections, were made to adjust the elevations of the extensions to NAVD 88 datum. The 32 sections with datum corrected were located between the STP site and the downstream boundary and were adopted from the PMF routing model described in Subsection 2.4S.3.
The locations and extents of the cross-sections used in the HEC-RAS dam break model are shown in Figure 2.4S.4-4.
2.4S.4.2.1.4 Manning’s n Values Used in the HEC-RAS Model The Manning’s n values used in the Halff HEC-RAS model were calibrated with historical storms and measured flood levels using the values suggested in Table 2.4S.4-4 (Reference 2.4S.4-10) as initial estimates. The calibrated values are in the range of 0.025 to 0.046 for the river channel and 0.045 to 0.100 for the overbank areas, and they were used in the Halff study to model flood conditions up to the SPF. The extensions in the dam break model adopted the same Manning’s n values assigned to the boundary limits of original cross-sections of the Halff model.
In a dam break event, there could be considerable amount of turbulence and entrainments of debris for many miles downstream of the breached section. In addition, a dam break flood, potentially with entrained debris, could overflow the river banks into the flood plains as well as inhabited areas, where the roughness could be considerably higher than those under severe flood conditions such as a SPF. To account for these conditions, the Manning’s n values used by Halff in its HEC-RAS model were adjusted upward conservatively by a factor of 2.0 for 4 miles immediately downstream from the each of the failed dams, i.e., 4 miles downstream from Buchanan Dam and Mansfield Dam, respectively. For the rest of the model river reach, the Manning’s n values were assumed to be 1.2 times that used in the Halff study (Base Case). A sensitivity case was performed using the same Manning’s n values as in the Halff study, except for a 4-mile distance downstream from Buchanan Dam as well as from Mansfield Dam where the Manning’s n values were two times the values used in the Halff study (Sensitivity Case). Increasing the Manning's n values increases the
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simulated water levels because of increased roughness and therefore is a conservative approach in estimating the maximum flooding water levels at the plant site.
2.4S.4.2.1.5 Predicted Water Levels at STP 3 & 4 from Upstream Dam Failure Model The HEC-RAS dam breach and unsteady flow routing model (Base Case) predicted that the peak water level at the STP site, without considering the wind wave effects, due to the domino-type failure of the upstream dams would be at El. 28.6 ft MSL or 28.4 ft (NAVD 88). The discharge at the time of the peak water level would be 1.87 x 106 cfs. For the Base Case, the flood wave would take about 65 hours to reach STP 3 & 4 after Mansfield Dam fails. This flood wave travel time would be about 58 hours for the Sensitivity Case. The predicted dam break flood and stage hydrographs for the two cases are presented in Figures 2.4S.4-9 and 2.4S.4-10. The simulated maximum dam break water surface profile from Buchanan Dam to the downstream boundary for the Base Case and Sensitivity Case are depicted in Figures 2.4S.4-11 and 2.4S.4-12, respectively.
2.4S.4.2.2 MCR Embankment Breach Analysis FLDWAV, a computer program developed by the National Weather Service (Reference 2.4S.4-12), was used to generate the outflow flood hydrograph from the MCR embankment breach, based on breach parameters discussed in Subsection 2.4S.4.2.2.2.2. This flood hydrograph was used as input to the two-dimensional flow model downstream of the breach.
RMA2 is a two-dimensional (2-D), depth-averaged finite-element hydrodynamic numerical model developed by the United States Army Corps of Engineers (USACE) (Reference 2.4S.4-12a). RMA2 was used to determine the flood elevations and velocities at the safety-related facilities of STP Units 3 and 4. The computer program can simulate dynamic water surface elevations and horizontal velocity components for subcritical, free-surface flow in a 2-dimensional flow field. The governing equations of RMA2 are the depth-integrated equations of fluid mass and momentum conservation in two horizontal directions. The governing equations are solved by finite-element method using the Galerkin Method of weighted residuals, and the integration in space is performed by Gaussian integration. Derivatives in time are replaced by a nonlinear finite difference approximation. The solution is fully implicit and the set of simultaneous equations is solved by the Newton-Raphson nonlinear iteration scheme. The computer code executes the solution by means of a front-type solver, which assembles a portion of the matrix and solves it before assembling the next portion of the matrix. The Surface Water Modeling System (SMS) (Reference 2.4S.4-12c) was used as the pre-and post-processor for the RMA2 model.
A 2-D model grid was developed based on topographic information and assigned parameters, such as Manning's roughness coefficient. Breach characteristics and a breach outflow hydrograph were incorporated into the 2-D grid, based on the breach analysis and FLDWAV results. A sensitivity analysis was conducted to evaluate the RMA2 results.
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The following paragraphs discuss the failure scenarios considered for the initiation of the postulated MCR breach. An overtopping failure of the MCR embankment is not considered because the freeboard above the normal maximum operating level is greater than 15 feet.
The MCR embankment contains an internal drainage system that provides control of through-reservoir seepage and underseepage potential within the embankment. This prevents the phreatic surface (where the hydraulic pressure head is zero) from increasing within the embankment to such a level as to lead to a potential catastrophic exiting of water at the downstream face of the embankment. Since the upstream (reservoir side) of the embankment has a soil-cement facing, seepage potential through the embankment is greatly reduced. However, the failure scenario adopted for this study conservatively assumes that the internal drainage system within the embankment substantially fails to provide its intended seepage relief function. This failure could occur through:
– Disruption of the horizontal drainage blanket through either a seismic event or activity of a growth fault that causes a break in this drain system.
– Blockage of relief wells by debris, rodents, siltation from embankment toedrainage backwater, or other means.
Disruption of the horizontal blanket drains could occur through shifting of the horizontal material layer during a seismic event or through activity of a growth fault. According to Subsection 2.5S.3.8.1, the potential for deformation due to seismic activity at the STP site is negligible, and there are no capable tectonic faults within the site vicinity. The potential for non-tectonic deformation and growth faults at the STP site are discussed in Subsections 2.5S.3.2.2 and 2.5S3.8.2. It was concluded that the potential for permanent ground deformation from activity on the growth fault structure at the site is negligible. Additionally, the potential for non-tectonic deformation at the site and the potential for non-tectonic deformation from movement on growth faults are considered negligible. Therefore, it is very unlikely that a failure of the drainage blanket would occur due to a postulated seismic event or activity due to growth faults.
The blockage of relief wells could conceivably occur if the existing surface drainage system at the toe of the embankment drains slowly or becomes plugged, creating a backwater effect. This backwater situation would allow silt within the standing water to settle, thus filling the drainage outlets. The internal seepage would then build-up within the embankment. This pressure build-up would eventually exit at the downstream toe of embankment. The saturation of the embankment could induce sloughing of the downstream toe section, providing a larger release area and a shorter flow path of seepage. Any free exiting of the seepage flow could allow movement of embankment material with subsequent generation of a piping failure.
The potential for an embankment failure due to piping caused by an uncontrolled water level build-up within the MCR embankment is considered very improbable for the following reasons: the engineered design of the MCR embankment; established operation and maintenance requirements that include embankment inspections and
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piezometer monitoring; the low probability of outlet drain plugging due to rodent activity; and the low probability of sediment deposition plugging the outlet drains. Therefore, the postulation of MCR embankment failure by piping is very conservative.
2.4S.4.2.2.1 Assumptions in the MCR Embankment Breach Analysis The following assumptions were used for the MCR embankment breach analysis:
(1) For modeling the flood elevation on the site, it was assumed that the large concrete structures such as STP Units 1 and 2 as well as Units 3 and 4, and several other tall and durable structures would remain in place during the flood. Other structures, such as metal skin buildings and warehouses, were assumed to be removed by the high velocity flood flow but have steel framing and associated remaining debris that would result in higher friction to flow. This higher friction to flow was incorporated by using a higher Manning's n for those elements.
(2) The bottom elevation of the MCR ranges approximately between elevations 16.0 ft and 28.0 ft. It was assumed that the average bottom elevation of the MCR is 20 ft (6.1 m), which is a representative low bed level in MCR.
(3) Breach side slopes were assumed to be 1 vertical to 1 horizontal for FLDWAV modeling.
(4) During the breach simulation it was assumed that there was no rainfall and therefore, there was no inflow to the MCR.
(5) It was assumed that the lateral expansion of the breach would occur symmetrically about its centerline.
2.4S.4.2.2.2 FLDWAV Flow Model Simulation FLDWAV is a parametric, numerical model used to generate the breach outflow hydrograph based on user-input breach parameters. The breach parameters are estimated using empirical equations developed from case studies of historical dam failures.
2.4S.4.2.2.2.1 Initial (Starting) Water Level in the MCR The starting water level in the MCR considered for the breach analysis was 50.9 feet. This level corresponds to the response of the MCR to one-half PMP on the normal maximum operating level plus the effect of wind set-up produced by the 2-year wind speed (50 mph) from the south (Reference 2.4S.4-7).
2.4S.4.2.2.2.2 Selection of the MCR Embankment Breach Parameters Reference 2.4S.4-12d by the Dam Safety Office of the U.S. Bureau of Reclamation describes several dam failure case studies that support empirical breach parameter relationships, and is considered the most complete and knowledgeable source for estimation of dam breach parameters. The breach parameters for the MCR
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embankment breach analysis were established based on discussions within this reference.
The portion of the northern embankment in line with and due south of Units 3 and 4 is the closest to the units, and therefore is considered the most critical location for a breach of the MCR embankment, with respect to flooding at STP 3 & 4. The top elevation of the embankment in this area is approximately El. 65.75 ft. A service road runs along the toe of the exterior slope of the MCR northern embankment. Due to an anticipated large scour hole that would occur at the breach location, it was assumed that the road would be eroded. The terrain immediately downstream of the road is considered to be the control for the breach bottom elevation. Therefore the breach bottom elevation was taken to be at El. 29 ft. Breach side slopes were taken to be 1 horizontal to 1 vertical, a ratio consistent with observations for earth-filled structures described in Reference 2.4S.4-12d.
Reference 2.4S.4-12d by the Dam Safety Office of the U.S. Bureau of Reclamation describes several dam failure case studies that support empirical breach parameter relationships. This reference describes several methods for estimating breach parameters. These methods include:
– Physically Based Methods: predicting the development of a breach and resulting outflow through use of an erosion model based on principles of hydraulics, sediment transport and soil mechanics.
– Parametric Models: using case studies of known dam failures to estimate time to failure and final breach geometry, then using these estimates within a computer model using principles of hydraulics.
– Predictor Equations: estimating peak discharge from empirical equations based on case studies of known dam failures.
– Comparative Analysis: using the breach shape and peak outflow of a dam that was of similar size and construction that had failed.
Physically based methods incorporate sediment transport and soil mechanics. In general, most of the available numerical dam breach models rely on bed-load type erosion formulas that utilize assumptions of gradually varied flow and relatively large flow depth in comparison to the size of roughness elements. These formulations are not consistent with the mechanics of the breaching process as observed in the field and in the laboratory. The other three methods listed above rely on case study data for selection of appropriate equations or parameters. In general, the database of welldocumented dam failure case studies is small and contains few examples of very large storage volumes such as the Main Cooling Reservoir.
Of the various methods, the parametric model method is the most generally utilized method, the method having the greatest research, and the method fully described within Reference 2.4S.4-12d. Table 2 of Reference 2.4S.4-12d describes nine dam failure case studies that lead to empirical breach parameter relationships. The breach parameters consisting of breach bottom width, time to fail, and breach side slopes were
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established based on discussions within Reference 2.4S.4-12d, engineering judgment, and the comparison to the Teton Dam failure. Of all the dam failures presented in Reference 2.4S.4-12d, the Teton Dam failure was chosen for comparison because the failure mode was piping and the Teton Dam reservoir had one of the largest storage volumes presented, similar to the MCR. The storage volume in the Teton Dam reservoir was approximately 1.5 times the storage volume in the MCR, and the Teton Dam had a significantly larger breach height of 254 feet versus 21.9 feet in the MCR. Each parameter is estimated independently and conservatively for use in FLDWAV.
The breach bottom width was based on Froehlich (1995b), presented in Reference 2.4S.4-12d. Froehlich’s equation, shown in Table 2.4S.4-5, predicts the largest breach width estimate of all methods presented in Reference 2.4S.4-12d. Froehlich’s equation provides conservative breach width results in comparison with breach widths from observed dam failures. For example, Froehlich's equation predicts an average breach width of 220 m (722 ft) for the Teton Dam. However, the actual average breach width of Teton Dam at failure was only 151 m (495 ft). Therefore, the breach width determined for the MCR embankment using Froehlich's equation is considered conservative. Froehlich’s equation predicts an average breach width of 417 feet. Given the trapezoidal geometry of the breach, the average breach width of 127 m (417 ft) yields a bottom breach width of 116 m (380 ft = 417 - 2(65.75 -29) / 2)), which was used for FLDWAV embankment breach modeling.
Time to fail was based on the equation given by MacDonald and Langridge-Monopolis (1984) presented in Reference 2.4S.4-12d. This equation, shown in Table 2.4S.4-5, predicts a time to fail that came closest to describing a breach expansion rate meeting that of Teton Dam. Breach expansion rate is determined using the predicted breach width and the time to fail. Typical rates of expansion vary from 60 feet lateral per hour to 120 feet lateral per hour. Teton Dam displayed a fairly rapid rate of breach expansion. Based on information presented in Reference 2.4S.4-12d, the time from beginning of rapid growth of breach to significant lateral erosion process stopping at Teton Dam was estimated at 1.25 hours and the final breach width was 496 feet, resulting in an expansion rate of 198 feet per hour. This rapid rate of erosion was due to the higher hydraulic depth to drive the outflow and associated erosion. The MacDonald and Langridge-Monopolis equation predicts a time to fail of 1.7 hours for the MCR. This gives a breach expansion rate for the MCR of approximately 112 feet lateral per hour, which is smaller than the Teton Dam and considered acceptable.
Finally, the breach side slopes were assumed to be 1 vertical to 1 horizontal. This ratio is consistent with all researchers’ observations for earth-filled structures, as discussed in Reference 2.4S.4-12d.
Table 2.4S.4-5 presents empirical equations from Reference 2.4S.4-12d and the resulting breach parameters.
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2.4S.4.2.2.2.3 MCR Embankment Breach Outflow Hydrograph The outflow hydrograph from the MCR embankment breach, generated by FLDWAV based on the aforementioned initial conditions and breach parameters is presented in Table 2.4S.4-6. The peak breach outflow predicted by FLDWAV is 130,000 cfs.
The peak discharge predicted by FLDWAV is compared to peak discharge estimates from other methods. Reference 2.4S.4-12d states that the Froehlich equation as shown in Table 2.4S.4-5 is one of the better available methods for prediction of peak breach discharge, because it correlates well with observed dam failure peak flow rates. The peak discharge estimated using Froehlich's equation is 62,600 cfs. The relationship of estimated peak discharges associated with the respective hydraulic head at time of failure from Reference 2.4S.4-12e is given in Figure 2.4S.4-13. From this figure, the peak flow for the MCR embankment breach is only 20,000 cfs, compared to 130,000 cfs as determined by the FLDWAV program. Therefore, the outflow hydrograph with a peak outflow of 130,000 cfs used in the breach analysis is conservative. To further verify the conservatism of the breach parameters and FLDWAV results, an independent analysis of the MCR embankment breach was performed using the BREACH model (Reference 2.4S.4-12e(1)) to predict the breach development and outflow hydrograph. This analysis is presented in Subsection 2.4S.4.2.2.2.4.
2.4S.4.2.2.2.3.1 Sensitivity Analysis of FLDWAV Parameters A sensitivity analysis was performed on the breach parameters selected for use in the FLDWAV model. The time to fail and the breach bottom width were tested separately to determine the effect of these parameters on the peak discharge predicted using FLDWAV. The results of the sensitivity analysis are shown in Table 2.4S.4-6a.
The data shown in Table 2.4S.4-6a indicates that the breach width has a significant effect on peak discharge. This is reasonable since the large storage to height ratio of this structure would allow little change to the hydraulic head due to volume loss of the breach hydrograph for any of the breach widths analyzed. Therefore, the change in breach width would produce a directly proportional change in breach area, which would in turn produce a directly proportional change in peak discharge.
Timing does not appear to be a significant factor. Lengthening the time to fail reduces the peak discharge; however, this reduction is slight. The results of the sensitivity of these parameters indicate that the peak breach outflow is more sensitive to changes in breach width than to the time to fail, or the breach formation time.
2.4S.4.2.2.2.4 Confirmatory Analysis Using the BREACH Model To verify the conservatism of the selected breach parameters and the FLDWAV results, an independent, confirmatory analysis of the MCR embankment breach was performed using the BREACH model. BREACH is a physically based mathematical model used to predict the breach development (breach size and time of formation) and the outflow hydrograph from the predicted breach of an earthen dam embankment (Reference 2.4S.4-12e(1)). Input data used by BREACH include embankment
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geometry and material properties, reservoir surface area-elevation relationship, and hydraulic characteristics of the channel formed directly downstream of the breach. BREACH couples the conservation of mass and momentum of the reservoir storage and breach outflow with the sediment transport capacity of the unsteady uniform flow along the breached channel. The growth of the breach is dependent on the dam embankment material properties (unit weight, friction angle, cohesive strength and particle size D50, for which 50 percent of the soil particles in the embankment material are smaller). The model simulates the development of the breach through the mechanism of one or more sudden structural collapses that occur when the hydrostatic force exceeds the resisting shear and cohesive forces; enlargement of the breach width by slope stability theory; and initiation of the breach via piping with subsequent progression to a free surface breach flow. For the BREACH model analysis, piping is considered as the breaching mechanism.
2.4S.4.2.2.2.4.1 Assumptions used in the BREACH Model Analysis The following assumptions were used for the BREACH model analysis of the MCR embankment:
(1) It is assumed that the lateral expansion of the breach will not be limited geologically or structurally to either the right or left of centerline.
(2) It is assumed that the piping starts at elevation 34.0 feet, which is the approximate centroid of the initial saturated zone in the failure scenario.
(3) The downstream control location was assumed to be the ditch along a service road. Due to an anticipated large scour hole that would occur downstream of the breach location, the slightly perched road was assumed to be removed by erosion and the natural terrain immediately downstream of the road considered to be the control for the breach bottom elevation of 29 feet. A Manning’s roughness coefficient of 0.06 was conservatively selected for the downstream channel routing reach. This reach has service roads, ditches, and small buildings that provide a roughness condition that would support the selected roughness coefficient. The downstream bottom slope was assumed to be 8 feet per mile.
(4) The cross section of the embankment has a berm on the downstream slope at approximately elevation 35 feet. This berm extends outward approximately 45 feet with a 6H:1V down slope. It was assumed that a potential breach mechanism would be an embankment slope failure that would, effectively, remove the berm altogether. Therefore, no effort was made in describing this berm cross section within the BREACH model. This is a conservative assumption.
(5) The soil cement protective layer on the upstream slope of the embankment was not considered in the BREACH model. The assumed piping failure would generate a head-cut progressing from downstream to upstream. The head- cutting action would remove the material from behind the soil cement protection layer, undermining the slope protection. Since soil cement has little
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tensile strength, the soil cement would not be able to maintain its integrity when unsupported. However, it would be reasonable to expect that the soil cement would not crumble immediately but would require some time after a piping failure has progressed. In addition, the effect of the soil cement liner is to decrease the breach erosion rate and hence increase the time to peak, resulting in a decreased peak breach outflow rate. Therefore, it is conservative to exclude consideration of the soil cement liner.
2.4S.4.2.2.2.4.2 Sensitivity Analysis of BREACH Model Inputs A sensitivity analysis was performed on selected embankment material parameters. The unit weight, internal friction angle and cohesive strength are based on field measurements or laboratory testing, and therefore sensitivity analyses were not performed for these three parameters.
It was found that varying both the critical shear stress coefficient and the critical stress coefficient (Ca and Cb) within their respective ranges recommended in Reference 2.4S.4- 12e(1) had no effect on the predicted peak breach discharge. Also, varying the plasticity index (PI) from 0 to 40 had no effect on the predicted peak discharge. Decreasing the value of D50 to that of a fine clay material (0.0001 mm) increased the peak discharge by less than a percent. Therefore, the peak breach discharge is not considered sensitive to these four parameters.
Changing the ratio of D90 (the soil particle size for which 90 percent of the embankment material is smaller) to D30 (the soil particle size for which 30 percent of the embankment material is smaller) by a factor of two either way changed the peak discharge by about 3 percent and hence was considered non-sensitive. Using a D90 to D30 ratio of 16 produced a higher discharge, but this ratio would indicate a well-graded material, which is not the case for the embankment material. The porosity ratio also was found to have a fairly insignificant effect on the breach outflow results. The 0.35 porosity ratio used is considered to be an upper end value. A compacted soil porosity value of 0.20 would be reasonable to assume for the embankment. Using a porosity ratio of 0.20 reduced the peak discharge by about three percent. Therefore, the higher porosity value of 0.35 was considered to be conservative.
Of all the parameters, the Manning’s n-value has the greatest effect on the predicted peak discharge. The Manning’s n-value within the BREACH model is computed using the Strickler relation of roughness to the average grain size (D50). The formula is defined as follows (Reference 2.4S.4-12e(1)):
0.67 n = 0.013 * (D50)
This formula produced an n-value of 0.001 for the MCR embankment. This value is unrealistically low. While using the BREACH model for Teton Dam breach analysis, Fread (Reference 2.4S.4-12e(1)) commented that the Strickler equation was judged not to be applicable for the fine breach material and used a relatively higher n-value of 0.013 for the analysis. For the present analysis a range of n-values were tested.
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N-values similar to those for a natural channel with clay material on all sides of the flow path were estimated based on engineering judgment and methods developed by others, such as Ven te Chow (Reference 2.4S.4-12e(2)). Using Table 5-5 within Reference 2.4S.4-12e(2), the n-value based on an earthen channel would be 0.02. Applying an additional 0.005 for irregularity of the flow channel, a combined total n- value of 0.025 was considered. The degree of irregularity and variation in cross section may be such that the overall n-value could be doubled, for an upper end value of 0.05. Therefore, an n-value within the range from approximately 0.025 to 0.05 was considered reasonable.
The BREACH algorithms are such that the lowest n-value considered, 0.025, produced a lower peak discharge than the highest n-value considered, 0.05. Therefore, consideration was given to a higher n-value of 0.08 that was still considered within the range of feasibility. Table 2.4S.4-6b presents the predicted peak discharge, breach width at time of peak discharge, time to peak discharge and reservoir level at time of peak discharge for each of the three n-values modeled. Figure 2.4S.4-13(a) presents the breach width development over time for all three n-values tested. The results of the sensitivity analysis indicate that higher roughness coefficients produce higher peak discharge values, which is counterintuitive. One explanation for this may be attributed to the model predicting a sudden collapse of the pipe section of the dam sooner with the lower n-values, thus lowering the peak discharge at a critical time. It is noted that the peak discharge and breach opening rate is based on several modeling algorithms that are balancing discharge forces, sediment transport rates and structural features with predicted storage depth and tailwater depth. An n-value of 0.05 is used in the FLDWAV analysis.
2.4S.4.2.2.2.4.3 BREACH Model Results and Comparison with FLDWAV The BREACH model results showing breach width development with respect to time of breach formation are presented in Figure 2.4S.4-13(b). The breach width increases initially at a fairly constant rate for the first five hours, after which the rate of breach expansion decreases. The peak discharge of approximately 83,200 occurs when the breach bottom width is 361 feet. The reservoir water level continues to drop as water flows out of the reservoir through the breach and the downstream channel erodes as it carries the large outflow from the breach. It is noted that the rate of erosion would decrease substantially after the first five hours of the breach process. However, considering the large volume of water remaining in the MCR, the breach continues to expand with diminishing outflow and a decreasing breach width erosion rate. The final breach width reached after 30 hours is 448 feet.
Table 2.4S.4-6c and Figure 2.4S.4-13(c) provide a comparison of the results from BREACH and FLDWAV. The breach width and time to peak used as input to the FLDWAV program were conservatively estimated based on case studies of historical dam failures presented in Reference 2.4S.4-12d. FLDWAV assumed a linear increase of the breach bottom width from 0 to a maximum width of 380 feet in 1.7 hours, which is the time the peak outflow occurs. The BREACH model produced the peak discharge 6.25 hours after the start of the breach development and allowed the breach width to continue to expand after the peak discharge. The BREACH model estimates a lower
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peak discharge as compared to the peak discharge predicted using the FLDWAV model. Even using an unrealistically high n-value of 0.08, the BREACH peak flow results are lower than the peak flow obtained with the FLDWAV model.
The BREACH model provides an independent assessment of the postulated breach of the MCR embankment at the STP 3 and 4 site. The BREACH model estimates a longer time to peak and a narrower breach width at the time of peak compared to the parameters selected for use in the FLDWAV model. BREACH also predicted a lower peak discharge than the peak discharge predicted using the FLDWAV model. Therefore, the parameters selected for FLDWAV and predicted breach hydrograph are considered conservative and acceptable.
2.4S.4.2.2.3 RMA2 Two-Dimensional Model Simulation After developing the maximum credible breach scenario, resulting hydrograph and resulting embankment erosion rates, the next step is to route the breach hydrograph to the safetyrelated facilities. Because of the complex topography of the site, a 2-dimensional (2D) simulation was considered appropriate. RMA2 has been used widely to conduct dynamic simulations of water level and velocity distribution in rivers, reservoirs, and estuaries, and is considered an acceptable tool to model the flood flow from the MCR embankment breach.
2.4S.4.2.2.3.1 Bathymetry Elevations and Two-Dimensional Grid Development The topography of the STP site was used to determine model bathymetry for routing the flood flow resulting from the MCR embankment breach. The 2-D grid was developed using: (1) STP Site Topography; (2) STP Units 3 and 4 Site Grading Plan; and (3) STP Units 3 and 4 Plot Plan. The grading plan around Units 3 and 4 power block site is shown in Figure 2.4S.4-14. The grade elevation at the center of the power block is EL. 36.6 ft and slopes to El. 32 ft at the four corners. Facilities included in the model grid are the Reactor, Turbine, Control, Radwaste, Service and Hot Machine Shop buildings for Units 1 through 4. The Ultimate Heat Sinks for Units 3 and 4 and Essential Cooling Pond (ECP) for Units 1 and 2 were also included in the model grid.
The datums of the 2-D grid are in NAD 27 State Plane Texas South Central for the horizontal datum and NGVD 29 for the vertical datum. The northern embankment of the MCR was selected as the southern boundary of the 2-D grid, and road FM 521 was chosen as the northern boundary of the grid. The western and eastern boundaries of the grid were selected to be sufficiently far from Units 3 and 4 so the target area is not impacted by the model boundaries (Figure 2.4S.4-15).
To assist the 2-D model stability associated with the wetting and drying of model elements and to further ensure that the target area is not impacted by model boundaries, a hypothetical sump was modeled along the east, north, and west boundaries of the developed 2-D grid outside of FM-521. The use of the sump to help with model stability is a common practice in the 2-D modeling field. Reference 2.4S.4-12e3 and Reference 2.4S.4-12e4 describe the use of sumps in physical models to control (and vary) the boundary conditions for calibration and the concept of “hybrid modeling” where results from a physical model of a complex region are used as input
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or boundary conditions for a comprehensive numerical model. References 2.4S.4-12e5 through 2.4S.4-12e8 show precedents for the use of artificial sumps in RMA2 applications. The sensitivity analysis described below indicates that the hypothetical sump has no impact on model results in and around Units 3 and 4. As a result, the developed 2-D grid (excluding the artificial sump area) covers an area of 1,477 acres: 5,873 ft in the north-south direction, and 12,455 ft in the east-west direction. Figures 2.4S.4-16 and 2.4S.4-17 show the 2-D grid with elevations for the east breach and west breach, respectively. The sump is the deeper area on the outside of the model grid.The 2-D grid includes 2,348 nodes and 1,088 elements. The size and location of these elements were selected to best represent physical features, particularly around Units 3 and 4. The areas of the 2-D elements range from about 2,500 square feet near the reactor buildings to about 144,000 square feet away from the units.
2.4S.4.2.2.3.2 Manning’s Roughness Coefficients The Manning's roughness coefficient (n value) for each model element was assigned based on typical values published by the United States Geological Survey (USGS) (References 2.4S.4-12f and 2.4S.4-12g) and the HEC-RAS manual (Reference 2.4S.4-12h). Each major building was evaluated on whether it would remain in place following the flood caused by a MCR embankment breach. Those buildings that were assumed to remain in place were considered "hard buildings." Any hard buildings higher than elevation 62 feet were considered to be a total blockage to the flow, and therefore were shown as blank areas in the 2-D grid. Those buildings assumed to fail were considered "soft buildings." Soft buildings were assumed to be destroyed with foundation slab remaining in the grid. These buildings were considered "high drag" areas with a higher roughness value to represent the effects of remaining frame and debris. Any buildings not included in the 2-D grid were represented by a higher Manning's n value. Due to the resolution of the grid, the Vehicle Barrier System around the power blocks was not built into the grid, but instead was represented by higher Manning's n value. Manning's n values assigned to each material type are listed in Table 2.4S.4-7. Figure 2.4S.4-18 shows the material types assigned to various elements in the 2-D grid. These Manning's n values were conservatively determined for each type of surface.
2.4S.4.2.2.3.3 Boundary Conditions The downstream boundaries of the model were positioned far enough downstream so that the maximum flood level at the STP Units 3 and 4 safety-related buildings due to a MCR embankment breach would occur before the flood front reaches the two boundaries. A constant water surface elevation was defined for the downstream boundary condition. A sensitivity analysis was performed on the downstream boundary condition, as discussed in Subsection 2.4S.4.2.2.4.1.
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2.4S.4.2.2.4 Results of MCR Embankment Breach Analysis
2.4S.4.2.2.4.1 Water Levels and Velocities Critical STP 3 and 4 site locations for RMA2 model results are shown on Figure 2.4S.4-19. To determine the maximum effect on each of the Units 3 and 4, separate east and west breach locations were simulated. The variation in water surface elevation at these locations from 1.2 hours to 2.5 hours of the model simulation are presented in Figures 2.4S.4-20 and 2.4S.4-21 for the east breach and west breach, respectively. This selected period includes the peak water level and peak velocity near the plant buildings. The peak water level of 38.8 feet occurred at the Unit 4 Ultimate Heat Sink structure for the west breach scenario. Peak water surface elevations for the east breach and west breach are shown on the plan grid in Figures 2.4S.4-21(a) and 2.4S.4-21(b), respectively. Peak velocities associated with the east breach and west breach are shown in Figures 2.4S.4-21(c) and 2.4S.4-21(d), respectively. The maximum velocity of the flood flow was found to be 4.72 feet per second and occurred between Units 3 and 4 (point 8 on Figure 2.4S.4-19). The variation in velocity at locations 1 through 8 for the period containing peak velocities for the east and west breach scenarios is shown in Figures 2.4S.4-21(e) and 2.4S.4-21(f), respectively.
As discussed above, the flood simulation provides peak water depth and peak velocity values at critical STP 3 and 4 site locations. Peak flood discharges per unit width near the power block buildings may be estimated using these values. Table 2.4S.4-7a provides examples of peak discharge per unit width estimated for locations near the Unit 4 UHS, the power block on the south side of Unit 4, and at a location between Units 3 and 4. These estimates are based on the west breach simulation results for peak water surface elevation and peak velocity, as shown in Figures 2.4S.4-21 and 2.4S.4-21(f), respectively. The water depths are obtained by subtracting the nominal site grade elevation in the power block of 34 feet from the peak flood water surface elevations.
A sensitivity analysis was conducted to determine the effect of boundary condition on the resulting water levels. The analysis indicated that changing the water surface elevation at the downstream boundary from 32.5 feet to 34 feet does not affect the peak flood levels for the site.
2.4S.4.2.2.4.2 Effects of Sedimentation and Erosion The MCR embankment breach analysis also considered the material eroded during the breach. The embankment material eroded is comprised mostly of clay, with a small percentage of sand from the internal drainage system and soil cement from the interior embankment slope lining. The erosion process will also produce a scour hole downstream of the breach that extends below the breach bottom elevation. The dimensions of this scour hole, based on lab results from Reference 2.4S.4-12i, are estimated to be 20 feet deep, 203 feet long and 380 feet wide. The scour hole contributes 1,543,000 cubic feet of clay to the flood flow. The material eroded from the MCR embankment contributes an additional 1,697,314 cubic feet of clay; 75,644 cubic feet of sand; and 117,562 cubic feet of soil cement. The total volume of sediment eroded under the breach scenario is 3,433,517 cubic feet.The flood flow from the MCR
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embankment breach would not cause erosion at the STP 3 and 4 plant site area because surfacing in this area is mostly concrete or asphalt pavement or compacted stone surfacing. The maximum velocity of 4.72 ft/s would not cause severe erosion of these surfaces, and any minor erosion around corners of the buildings would not impact the safety-related facilities of Units 3 and 4. Therefore, the power block surfacing would remain intact following the MCR embankment breach flood.
It is anticipated that sedimentation will not have a significant effect on the site and the maximum water level resulting from the MCR breach flood. The majority of the clay and sand loads would be suspended in the flood flow and washed downstream, north of FM 521 and beyond the STP site. The soil cement lining on the interior wall of the embankment would likely enter the water as chunks or blocks as the embankment collapses, and these large concrete blocks would be carried only a short distance from the breach before settling to the bottom. The sediment loading would cease when the breach opening expansion ends; however, low-sediment flows would continue for a number of hours afterwards until the water in MCR is totally emptied. This continued flow period would prevent any remaining clay or sand particles from settling and would wash away any small depositions in the study area.
RMA2 does not have sediment transport modeling capabilities, thus a bounding analysis was performed to determine a conservative sediment accumulation depth within the Units 3 and 4 power block area. This analysis is based on conservatively assuming twice the calculated total sediment volume from the MCR breach and scour hole and applying it on a fan area (potential sediment deposition area) extending from the breach to the peripheral road to estimate the maximum sediment depth near the plant area. Though the sediment material is primarily clay, most of which would remain in suspension, it is assumed for this bounding analysis that all the material settles uniformly within the fan area.
The analysis includes both the east and west breach scenarios. For each of the scenarios, a sediment fan area is considered that extends from the MCR breach to FM 521. The fan areas, shown in Figure 2.4S.4-21(f1), were selected by reviewing the RMA2 flow fields so that the fan areas follow the main path of the simulated breach flows. The total area of selected 2-D elements within a fan area is reported automatically by SMS. The building areas are excluded from the area calculations. The total volume of sediment material considered for this analysis is 6,867,040 cubic feet. The areas of the fans for the east and west breach scenarios are 19,646,580 square feet and 17,948,623 square feet respectively. The estimated sediment depths within the fan areas are 0.35 feet and 0.38 feet for the east and west breach scenarios, respectively.
The bounding analysis shows that the sediment depths near the power block would be in the range of 0.35 to 0.40 feet. Even with the sediment depth of 0.4 feet, and further assuming that the flood water elevation were raised by the same amount, the maximum water level due to MCR breach flood would be 39.2 feet instead of 38.8 feet. The design basis flood level of 40 feet for the STP Units 3 and 4 will not be affected due to sedimentation.
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2.4S.4.2.2.4.3 Hydrodynamic Forces The maximum water levels and velocities obtained near Units 3 and 4 were used to assess the hydrodynamic loadings on the plant buildings. Figures 2.4S.4-21(e) and 2.4S.4-21(f) show the time-dependent plots of the velocities during the east and west breach scenarios, respectively. The peak velocities observed in between Units 3 and 4 were 4.72 and 4.68 feet per second for the east and west breach scenarios, respectively. The sediment loads associated with the flow from the MCR embankment breach were developed to determine sediment concentrations and the sediment-laden water density. The time-dependent, well-mixed sediment concentrations were obtained assuming that no sediment gets transported outside of the study domain. The sediment concentration corresponding to the peak velocity occurring at T=1.7 hours was 22.33 kg/m3. Therefore, a sediment concentration of 23 kg/m3 was used to determine the sediment-laden water density. With a sediment concentration of 23 kg/m3, a water density of 1023 kg/m3 or 63.85 lb/ft3 was used for load calculations. The maximum hydrostatic force on any plant building would be due to the depth of floodwater at the maximum water level. Hydrodynamic loads were calculated using the drag force formula with a drag coefficient conservatively set to 2.0, as presented below:
Force (lb/ft2) = 2.0 x Density (lb/ft3) x Velocity2 (ft2/sec2) / 2g
The maximum drag force due to the maximum velocity of flow near the plant buildings is estimated as 44 pounds per square foot of the projected submerged area of the buildings.
The hydrodynamic loads due to wind-generated waves have also been calculated. A two year fastest mile wind speed of 50 mph, based on Reference 2.4S.4-7, is conservatively applied coincident with the Main Cooling Reservoir (MCR) breach flood level. The methodology given in the Coastal Engineering Manual (CEM), Reference 2.4S.4-13, is used to estimate the wave height and wave forces on the vertical walls of the power block buildings.
Based on the site layout and considering the sheltering effect of other buildings or structures on the site, the controlling fetch length will be due to the westerly winds. Therefore, the longest fetch on the west facing Unit 4 safety-related structures is determined. For this governing condition, the wave height is calculated for the above wind speed, fetch and the depth of water along the fetch. Based on this, a significant non-breaking wave with a wave height (Hs) of 1.25 feet and a period (T) of 1.7 seconds would be generated. Considering a 1% wave height (H1= 1.67 Hs) of 2.1 feet, per Reference 2.4S.4-7, the wave force due to the wind generated waves is calculated and conservatively applied to all the safety-related structures including those for Unit 3.
The resultant hydrodynamic wave force is calculated to be 603 pounds (0.6 kips) per foot length of the vertical wall corresponding to the maximum breach flood level of 38.8 feet. The wave force diagram is shown in Figure 3.4-1.
Due to the waves generated by the postulated wind the water level near the safety- related structures will fluctuate above and below the still water level caused by the
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MCR dike breach flood. As stated above, the water levels near the Unit 4 safety-related structures are affected more than the water levels near the Unit 3 structures due to the controlling westerly winds. Therefore, the rise in water level due to wind wave effect near Unit 4 safety-related structures is considered as the upper bound water level fluctuation for the Unit 3 structures also.
Following are the maximum water levels near Unit 4 safety-related structures due to MCR dike breach flood and the fluctuation of the water level due to the wind waves. The MCR dike breach flood levels are described in Section 2.4S.4.
– Maximum water level due to MCR breach flood near the Unit-4 Ultimate Heat Sink (UHS) = 38.8 feet
– Maximum water level due to MCR breach flood near the Unit-4 power block structures = 38.2 feet.
– Maximum periodic rise in water level due to wind wave action = 3.1 feet (see Figure 3.4-1)
Including the fluctuation in water level due to wind wave effect;
– The maximum water level near the Unit-4 UHS = 38.8 + 3.1 = 41.9 feet.
– The maximum water level near the Unit-4 power block structures = 38.2 + 3.1 = 41.3 feet.
The UHS and Reactor Service Water (RSW) Pump Houses are designed to be watertight below 50 feet MSL. All the power block safety-related structures are watertight below elevation 41.0 feet MSL due to one foot threshold provided above the design basis flood level of 40 feet MSL. Any periodic splash flooding above the 41-foot elevation up to the wave run-up elevation of 41.3 feet MSL will be minor and would be taken care of with normal housekeeping and will not affect the safety-related function of the structures.
2.4S.4.2.2.4.4 Spatial Extent of Flooding Due To MCR Embankment Breach For both the east and west MCR embankment breach scenarios flood water from the breach opening will flow through the area encompassing Units 1 and 2 and Units 3 and 4, and will spread into the area bounded by FM 521. The model simulations end at the boundary cells immediately outside of FM 521. This road has a top of road elevation of approximately 28 feet to 30 feet, as seen from the USGS topographic map of the area (Figure 2.4S.4-21(i)). North of FM 521 and west of the west MCR embankment there are levees with approximate top elevations of 29 feet to 30 feet. South of the MCR along its south embankment is an east - west canal with levees on both sides. The area around the STP plant has an approximate grade elevation varying from 25 feet to 30 feet.
The area around the STP plant slopes east towards the Colorado River. Therefore, most of the flood water from the breach would flow to the Colorado River. A portion of
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the breach flow will also reach the Little Robins Slough to the west, which flows south along the west MCR embankment. From there, the water will either flow east to the Colorado River or will flow under the east-west canal through existing siphons and may flow through several swampy areas to the intracoastal waterway.
A small portion of the breach flood flow may reach the Tres Palacios River to the west of the STP site.
2.4S.4.2.2.4.5 Duration of Inundation at Safety-Related SSCs The duration of inundation at the power block is considered to be the duration during which the flood elevations are greater than the grade elevation of 34 feet. Since the primary purpose of the breach flood modeling was to determine the maximum flood elevation at safety-related facilities, the simulation was terminated after the maximum flood elevation was reached, well before all the water had drained from the site. As a result, a full RMA2 simulation for the duration of the flood water above elevation 34 feet was not performed. However, a reasonable estimate of this duration of inundation can be obtained by relating the resulting flood elevations generated from the RMA2 run to the corresponding flow rates from the breach outflow hydrograph, occurring at the same time. The flood elevations and outflows are plotted on the same graph with time as the common base, as shown in Figure 2.4S.4-21(j). Extrapolated flood elevations were estimated by fitting a non-linear polynomial regression curve. The time elapsed between the two points corresponding to a flood elevation of 34 feet at the power block is estimated at 20.5 hours. Therefore, the estimated duration of inundation (above 34 feet) at safety-related SSCs is 20.5 hours.
2.4S.4.3 Water Level at the STP 3 & 4 Site Analyses of the dam failures on the Lower Colorado River and the failure of the MCR northern embankment showed that the critical flood level of the safety related structures is controlled by the MCR embankment failure. The design basis flood level for the safety related facilities of STP 3 & 4 is conservatively established as 40.0 ft MSL as discussed below.
2.4S.4.3.1 Water Level at the STP 3 & 4 Site from the Failures of Upstream Dams In accordance with the guidelines in ANSI/ANS-2.8, Reference 2.4S.4-7, the maximum dam breach flood level at the plant site needs to consider the wind setup and wave runup effect from the coincidental occurrence of a 2-year design wind event. The 2-year fastest mile wind speed at the site is 50 mph based on Reference 2.4S.4-7. The methodology given by the Coastal Engineering Manual (CEM), Reference 2.4S.4-13, was adopted to estimate the wave height and wave run-up at STP 3 & 4 power block. The procedures outlined in CEM use the wind speed, wind duration, water depth, and over-water fetch distance, and the run-up surface characteristics as input. As discussed in UFSAR for STP 1 & 2 (Reference 2.4S.4-5), accurate estimates of the fetch length for this flooding scenario could not be made. Based on the topographic variations and any man-made features that would limit wind effects, however, two critical fetches were identified as shown in Figure 2.4S.4-22; one in an easterly direction towards a low lying ridge and the other along the Colorado River in a northeasterly direction. The fetch in the easterly direction was estimated to be about
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15.5 miles with a maximum water depth varying from 1 to 23 ft at the peak of the dam break flood. The fetch along the northeasterly direction was estimated to be about 17.6 miles, with a maximum water depth varying from 1 to 9 ft at the flood peak.
The maximum wind set-up for the critical fetch lines was estimated using a method suggested in Reference 2.4S.4-14, and was found to be about 3.9 ft. Adding to the maximum water level of El. 28.6 ft MSL, estimated by the HEC-RAS dam break model for the STP site, the water level from the dam failure flooding scenario would therefore be at El. 32.5 ft MSL. With the surrounding site grade around the power block and UHS at a nominal elevation of 28.0 ft MSL, the water depth approaching at the STP power block and UHS would be about 4.5 ft. At this shallow depth, a breaking wave condition would prevail and a breaking wave index of 0.78 was used in estimating the break wave height. The breaking wave setup is typically small and is assumed to have a negligible impact on the flood level.
All the safety-related facilities including the UHS are located in the power block island. The power block island will have a grade elevation of approximately 34.0 ft near the plant buildings and will slope towards the periphery to an elevation of 32.0 ft at the edges. The outward slope of the island will be at 10H:1V from elevation 32.0 ft to an existing grade elevation of 28.0 ft.
The maximum wave run-up was estimated using the breaking wave height of 3.5 ft and a maximum wave period equal to 1.2 times of the significant wave period which was estimated to be 3.7 seconds. Conservatively assuming that the run-up surface is smooth, impermeable and using a slope of 10H:1V for the power block island, the wave run-up was estimated to be 1.9 ft.
The maximum flood level at STP 3 & 4 power block as a result of the probable worst case dam failure scenario coincidental with a 2-year design wind of 50 mph was estimated to be at El. 34.4 ft MSL. Table 2.4S.4-8 presents the water levels due to dam break, wind set-up and wave run-up at STP 3 & 4 for the critical fetch.
Because the STP is about 300 miles from Mansfield Dam, any dynamic effects of the dam break waves would have been attenuated along this distance. Therefore, the dynamic effects of the dam break flood waves are not the controlling design criterion of the safety related facilities.
2.4S.4.3.2 Water Level at the STP 3 & 4 Site from Breaching of MCR Embankment The maximum water level at STP 3 & 4 is governed by the postulated breaching of the MCR’s northern embankment. The design basis flood level at the power block and UHS of STP 3 & 4 based on the breaching of the MCR’s northern embankment is at El. 40.0 ft MSL. Because the design basis flood level is higher than both the nominal plant grade of 34.0 ft MSL and the entrance level slab elevation of 35.0 ft MSL for the STP 3 & 4 safety related facilities, all safety related facilities are designed to be water tight at or below elevation 40.0 ft MSL. All ventilation openings of safety buildings are located at 40.0 ft MSL or above. Flood protection design is discussed in Subsection 2.4S.10 and Section 3.4.
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2.4S.4.3.3 Sedimentation and Erosion During an upstream dam failure event, because the plant site is located in the floodplains of the Colorado River, the flow velocities are expected to be relatively small compared to that in the main channel. In addition, the flow depths on the floodplain are shallower to effect any significant erosion that would impact the safety of the plant. Although some sedimentation may occur near the plant site, the safety related structures and functions would not be affected by siltation because they are located at higher grades than the surrounding area.
The erosion and sedimentation during a MCR embankment breach event is discussed in Subsections 2.4S.4.2.2.4.2 and 2.4S.10.
2.4S.4.4 References 2.4S.4-1 “Texas Administrative Code – Title 30, Part 1, Chapter 299,” Office of the Secretary of State of Texas, provisions adopted to be effective May 13, 1986 (11 TexReg 1978).
2.4S.4-2 “Phase II – Dam Safety Evaluation Project, Task Order B – Reconnaissance investigation, Interim Report,” Volume I, Freese and Nichols, Inc., August 1992.
2.4S.4-3 “Celebration marks completion of 10-year LCRA dam project to improve public safety,” Press Release by LCRA dated January 12, 2005; available at http:/www.lcra.org/newsstory/2005/dam_upgrade_project.html, accessed on August 31, 2007.
2.4S.4-4 “Disaster Ready Austin: Building a Safe, Secure and Sustainable Community,” City of Austin Hazard Mitigation Action Plan, 2003 – 2008, prepared by LCRA and H2O, Inc., revised on August 7, 2003.
2.4S.4-5 STPEGS Updated Final Safety Analysis Report, Units 1 & 2, Revision 13.
2.4S.4-6 “Water for Texas – 2007,” Volumes I, II, and III, Texas Water Development Board, January 2007.
2.4S.4-7 Determining Design Basis Flooding at Power Reactor Sites,” La Grange Park, Illinois, ANSI/ANS-2.8-1992, American Nuclear Society, July 1992. (Historical Technical Reference)
2.4S.4-8 “Engineering Data on Dams and Reservoirs in Texas,” Part III, Report 126, Texas Water Development Board, February 1971.
2.4S.4-9 “HEC-RAS, River Analysis System, Version 3.1.3,” U.S. Army Corps of Engineers, Hydrologic Engineering Center, May 2005.
2.4S.4-26 Potential Dam Failures Rev. 12
STP 3 & 4 Final Safety Analysis Report
2.4S.4-10 “Flood Damage Evaluation Project,” Chapter 1-6, Volume II-C, Volume II-B, Halff Associates, Inc., July 2002.
2.4S.4-11 “Industries Regulations, Guidelines and Manual – Engineering Guidelines for the Evaluation of Hydropower Projects,” Federal Energy Regulatory Commission, April 1991.
2.4S.4-12 D. L. Fread and J. M. Lewis, "NWS FLDWAV Model Theoretical Description and User Documentation," Hydrologic Research Laboratory, Office of Hydrology, National Weather Service, U.S. National Oceanic and Atmospheric Agency, Silver Spring, Maryland, 1998.
2.4S.4-12a "User's Guide to RMA2 WES," Version 4.5., Coastal and Hydraulics Laboratory, Waterways Experiment Station, Engineer Research and Development Center, U.S. Army Corps of Engineers, April 22, 2005.
2.4S.4-12b Not Used
2.4S.4-12c Surface-water Modeling System (SMS), Version 10.0.7, Aquaveo, August 29, 2008.
2.4S.4-12d T. L. Wahl, "Prediction of Embankment Dam Breach Parameters, A Literature Review and Needs Assessment", Dam Safety Research Report DSO-98-004, Dam Safety Office, Water Resources Research Laboratory, U.S. Department of the Interior, Bureau of Reclamation, July 1998.
2.4S.4-12e "Guidelines for Defining Inundated Areas Downstream from Bureau of Reclamation Dams," Reclamation Planning Instruction No. 82-11, Dam Safety Office, U.S. Department of Interior, Bureau of Reclamation, Denver, Colorado, 1982.
2.4S.4-12e1 Fread, D. L., BREACH, “An Erosion Model for Earthen Dam Failures”, Hydrologic Research Laboratory, Office of Hydrology, National Weather Service, U.S. National Oceanic and Atmospheric Agency, Silver Spring, Maryland, July, 1988.
2.4S.4-12e2 Chow, Ven te, Open Channel Hydraulics, McGraw-Hill Book Company, 1959.
2.4S.4-12e3 Ettema, R. Hydraulic modeling: concepts and practice. Environmental and Water Resources Institute (U.S.). ASCE Publications. 390 pages, 2000.
2.4S.4-12e4 Hughes, S.A. 1993. Physical Models and laboratory techniques in coastal engineering. USACE. ERDC.
Potential Dam Failures 2.4S.4-27 Rev. 12
STP 3 & 4 Final Safety Analysis Report
2.4S.4-12e5 Su, Y.C., E. Lehotsky, and D. Fuller. 2009. “The Sabine Pass LNG Terminal, Challenges for a new LNG Terminal in Louisiana”, Caring for the Coast: Texas Coastal Conference 2009, Galveston, Texas, June 4-5, 2009.
2.4S.4-12e6 Su, Y.C. and J. Mahmoud. 2007. Beneficial use of dredged materials at Louisiana shoreline near Sabine Pass. International Erosion Control Association Conference, Reno NV.
2.4S.4-12e7 Su, Y.C., J. Koutny, J. Benoliel, J. Mahmoud, M. Heaney, and D. Granger. 2005. “Sediment Transport Modeling of Dredged Disposal Materials Near Sabine Pass.” Coastal Texas 2020 Technical Erosion Conference 2005, Houston, Texas, September 14-16, 2005.
2.4S.4-12e8 Su, Y.C., C. Woodward, J. Koutny, and J. Benoliel, and W. Crull. 2004. “Modeling of Flood Control Channels Using SMS/RMA2.” TFMA 17th Annual Texas Flood Conference, Fort Worth, Texas, 2004.
2.4S.4-12f G. J. Arcement and V. R. Schneider, "Guide for Selecting Manning's Roughness Coefficients for Natural Channels and Flood Plains," Water-Supply Paper 2239, United States Geological Survey, 1989.
2.4S.4-12g "Flood Damage Evaluation Project," Chapter 1-6, Volume II-C, Volume II-B, Hall Associates, Inc., July 2002.
2.4S.4-12h "HEC-RAS, River Analysis System, User's Manual," Version 3.1.3, U.S. Army Corps of Engineers, Hydrologic Engineering Center, May 2005.
2.4S.4-12i Z. Xiuzhong and W. Guangqian, "Flow Analysis and Scour Hole Computation of Dyke-Breach.," Proceedings of the International Association for Hydraulic Researchers XXIX Congress, Theme E, Tsinghua University, Beijing, China, September 16-21, 2001.
2.4S.4-13 “Coastal Engineering Manual,” U.S. Army Corps of Engineers, June 2006.
2.4S.4-14 “Advanced Series on Ocean Engineering, Volume 16, Introduction to Coastal Engineering and Management,” J. William Kamphuis, 2000.
2.4S.4-15 “Colorado River – Flood Guide,” Lower Colorado River Authority, Texas, January 2003.
2.4S.4-28 Potential Dam Failures Rev. 12
STP 3 & 4 Final Safety Analysis Report Date of Completion 1963 1933 1969 1966 1952 1948 1952 1989 1977 1963 1959 1937 1990 1942 1952 1949 Arch, Gated and and Gated Arch, Gravity sections Embankment Earth and Rockfill and Earth Maximum top of dam)of top Type Dam 15,404 [1] Concrete Gravity 1939 Capacity (AF at Capacity 207,265 Earth 3,300,000 [4] Concrete Gravity 63,500 [1]63,500 Gravity Concrete 1938 101,000 [4]101,000 Earthfill 1 5 [4] 226,000 Earthfilland Concrete 1951 (ft MSL) (ft Elevation Top ofDam 2104 83,800 [3] Earthfill ft: top of top of ft: parapet) 0 1584 [4] 1,470,000 Earth and Rock Fill ,800 2090 78,400 [4] Earthfill Dam (ft) Length of (ft) Height Height of Dam County Burnet 118.29 5,491 835.2 Travis 266.4 7,089 (754.1 750.1 Burnet 96.5 1,547.5 922 McCulloch 104 8,400 1783 [3] 213,000 Earthfill Travis 85 1,590 519 Burnet 145.5 10,987 1025.35 [1] 1,180,000 Concrete Multiple Table 2.4S.4-1 Summary of the 68 Dams in Colorado River Basin with 5,000 AF or More Storage Capacity AF or More Storage with 5,000 Basin in Colorado River 68 Dams of the Summary 2.4S.4-1 Table No. Name Dam 1415 [5] Dam Creek Champion Mitchell16 Dam Creek Cedar 17 Oak Creek Dam [5] 11418 Colorado City Dam [5] Fayette19 [5] Dam Creek Hords Coke 6,800 Mitchell Inks Dam Roy 96 Coleman 2109 85 95 91 8,000 4 [3] 103,600 3,800 401 6,800 Earthfill 1939[3] 66,300 Earthfill 10 Dam [5] Brady 13 [5] Dam Coleman Coleman 90 3,200 1740 [3] 108,000 Earthfill 0506 Dam [5]Lee Robert 07 Dam [5] O C Fisher 08 Dam [5] Brownwood Coke09 Dam [5] J Lake B Thomas Green Tom Scurry Brown Alvin Wirtz Dam 128 14011 10512 40,885[5] [1] Dam Natural 120 21,500 Miller Dam Tom 1964 14,500 1928 1,580 Howard 2280 1449.5 [2] 815,000 47 [3] 1,074,000 [2] 431,000 [1] 448,2000 Earthfill Earthfill [6] Earthfill Earthfill [6] 0304 Dam [5] Buttes Twin Dam Buchanan Green Tom 134 42,460 1991 [3] 1,294,000 Earthfill 02Freese Dam [5] Simon Coleman 148 15,95 01 Dam Mansfield
Potential Dam Failures 2.4S.4-29 Rev. 12
STP 3 & 4 Final Safety Analysis Report Date of Completion Earthfill 1990 Maximum top of dam)of top Type Dam Capacity (AF at Capacity ft, msl ft, (ft MSL) (ft Elevation Top ofDam Dam (ft) Length of 5,300 known Not 170 EL at 9,600 (ft) Height Height of Dam ft +/- County Mitchell 70Runnels [6] 76 [6]Travis 6,200Callahan 1,694 50,241 33Mcculloch 63 34,353 [6] 50Concho 3,950 Earth 50Concho [6] 4,208 1888.9 42 Earth [6]Runnels 5,910 6,459 [3] 20,000 1991 20,692 [6] 37 [6] Earthfill 13,511 1985 3,090 Earth 11,155 1800.2 13,042 Earth 1970 10,032 Earth Earth 1993 Earth 1962 1958 1957 1945 ConchoColeman 43 57 4,010 2,631 [6] [6] 9,494 9,416 Earth Earth 1959 1971 [5] [5] Dam [1] [5] Dam [1] Site 7 Dam [5] SCS 17 Dam [1] [5] 28 Dam [1] [5] 31 Dam [1] [5] [5] Dam [1] 20 Dam [1] [5] [5] Site 5A Dam [1] SCS Table 2.4S.4-1 Summary of the 68 Dams in Colorado River Basin with 5,000 AF or More Storage Capacity (Continued) Capacity Storage AF or More with 5,000 Basin River in Colorado 68 Dams of the Summary 2.4S.4-1 Table No. Name Dam 20 [1] Dam County Mitchell 2122 Dam Creek Decker 23 [5] Dam Nasworthy Lake Ballinger Municipal Travis24Green Tom 25 [5] [1] Dam Elm Creek 5026 83 Dam Bastrop Runnels Draw Springs Sulphur 27 5,480 6,390 57 Bayou WS Pecan Upper 1883.528 563 Bastrop Brady Creek WS SCS Site 5,64029[4] 43,300 85 1,810 Brady Creek WS SCS Site [2] 45,300 30 Brady Creek WS SCS Site Earthfill 4,00031 33,500 Earthfill 458 Old Lake Winters City 32 [2] Dam Lake Eagle Earth 1930 [1] 24,200 1967 Colorado Earthfill 6 Varies 1983 1964 33 Brady Creek WS SCS Site 34 WS Laterals Northwest
2.4S.4-30 Potential Dam Failures Rev. 12
STP 3 & 4 Final Safety Analysis Report Date of Completion 1951 weir Gated Maximum top of dam)of top Type Dam Capacity (AF at Capacity 8,760 [1] ConcreteRoof- with (ft MSL) (ft Elevation Top ofDam 738 [7] 738 Dam (ft) Length of (ft) Height Height of Dam County ColemanColeman 44Runnels 64 2,400 [6] 30 2,000 [6] 4,400 8,368 1704.6 8,271 8,215 Earth Earth Earth 1963 1965 1947 RunnelsBrown 39Coleman [6] 50Brown 92 2,101 [6]Callahan 1,915 45 1461Mcculloch 69 [6] 2,300 8,165 43Coleman 8,083 2,025 1508.6Nolan 45 4,091 7,930 1948.8 Earth 7,891Coleman [6] Earth 2,410 52 7,833 50 [6] Earth 5,100 Earth 7,732 1,800 2004 Earth 2121.8 1958 7,679 1606.4 1963 7,600 Earth 7,394 1958 Earth 1967 Earth Earth 1956 1974 1968 1972 NRCS Site Site 25 Dam [1] [5] Site 12E1 Dam [1] [5] [1] [5] 3 Rev. [1] [5] 3 Rev. [5] [1] Dam 6 Site 21 Dam [1] [5] [5] [1] Dam 4 [5] Site 2 Dam [1] SCS 14 Dam [1] [5] 13 Dam [1] [5] [5] [1] Dam 1 SCS Site 24 Dam [1] [5] Table 2.4S.4-1 Summary of the 68 Dams in Colorado River Basin with 5,000 AF or More Storage Capacity (Continued) Capacity Storage AF or More with 5,000 Basin River in Colorado 68 Dams of the Summary 2.4S.4-1 Table No. Name Dam 36 Jim Ned Creek WS SCS 37 Jim Ned Creek WS SCS 38 Ballinger City Lake Dam 39 Elm Creek WS 40 Clear Creek WS SCS Site 41 Jim Ned Creek WS SCS 42 Clear Creek WS SCS Site 43 Bayou WS Pecan Upper 44 Brady Creek WS SCS Site 45 Home Creek WS SCS Site 46 Creek WS SCS Site Valley 47 Bayou WS Pecan Upper 35 Dam Max Starcke Burnet 98.8 860 766 [1]
Potential Dam Failures 2.4S.4-31 Rev. 12
STP 3 & 4 Final Safety Analysis Report Date of Completion Maximum top of dam)of top Type Dam Capacity (AF at Capacity (ft MSL) (ft Elevation Top ofDam Dam (ft) Length of (ft) Height Height of Dam County BrownRunnels 83 32Concho 50 1,930 8,075 2,520 1473.9Coleman [6] [6]Runnels 62 7,377Coleman 39.5 1,980 7,053 7,181Coleman 48 [6] [6] EarthColeman 84 3,396 [6] Earth EarthRunnels 35 6,754 [6] 1,900 1973 Brown [6] 23 3,190 6,500San Saba 6,367 1485.7 Earth 1959 1964 450 55 43Concho 6,334 Earth 6,130 1635 1,950Callahan 2,225 Earth 30 1451.5 1962 [6] 65 6,018 Earth 3,543 Earth 5,988 1998 1,400 [6] 1970 5,899 1759.3 Earth 1963 Earth 1965 5,742 5,707 Earth 1930 Earth Earth 1960 1968 1958 1967 SCS Site 3 Dam [1] [5] Site 3 Dam [1] SCS [5] Site 1 Dam [1] SCS 32 Dam [1] [5] Site 23 Dam [1] [5] [5] [1] 7 [5] 7A Dam [1] Site 12 Dam [1] [5] SCS Site 10A Dam [1] [5] [5] [5] [1] Dam 3 [5] [1] Dam 7 21 Dam [1] [5] SCS Site 12 Dam [1] [5] Table 2.4S.4-1 Summary of the 68 Dams in Colorado River Basin with 5,000 AF or More Storage Capacity (Continued) Capacity Storage AF or More with 5,000 Basin River in Colorado 68 Dams of the Summary 2.4S.4-1 Table No. Name Dam 48 WS Laterals Brownwood 49 WS Laterals Northwest 50 Brady Creek WS SCS Site 5152 [1] Dam Longhorn Jim Ned Creek WS SCS 53 Travis Elm Creek WS NRCS Site 54 Home Creek WS SCS Site 6555 Jim Ned Creek WS SCS 56 1,240 Mukewater Creek WS 57 464 [1] Dam Lake Creek Elm 58 Clear Creek WS SCS Site 6,85059 Se Laterals WS SCS Site 60 Brady Creek WS SCS Site Gravity Earth, 61 Bayou WS Pecan Upper 1960
2.4S.4-32 Potential Dam Failures Rev. 12
STP 3 & 4 Final Safety Analysis Report Date of Completion Maximum top of dam)of top Type Dam Capacity (AF at Capacity (ft MSL) (ft Elevation Top ofDam on the storage-stage curves in Reference 2.4S.4-8 in Reference curves the storage-stage on Dam (ft) Length of (ft) Height Height of Dam County HowardLee 67Concho 2,450 25Coleman 33 2341.6Coleman 4,050 52 1,973 5,700 450.9Taylor 46 2,082 [6]Brown [6] 4,000 28 5,627 Earth [6] 5,352 40 2,985 5,297 Earth [6] 1,542 5,280 Earth 1939 1397.6 Earth 5,218 5,128 1958 Earth 1955 Earth 1964 Earth 1966 1960 1960 Data provided by TCEQ provided Data 2.4S.4-8 Reference in provided was listed Data bydi rectly TWDB: data based extrapolated were TWDB: data by provided Data data area the storage-stage based on extrapolated were TWDB: data by provided Data Dams located upstream of Buchanan Dam No information was given by TCEQ 2.4S.4-15 Reference LCRA in from Data Site 1 Dam [1] 36 Dam [1] [5] [5] Site 2 Dam [1] SCS 26ASite [5] Dam [1] Site 19 Dam [1] [5] [5] [1] Dam 1 [5] Table 2.4S.4-1 Summary of the 68 Dams in Colorado River Basin with 5,000 AF or More Storage Capacity (Continued) Capacity Storage AF or More with 5,000 Basin River in Colorado 68 Dams of the Summary 2.4S.4-1 Table [1] [2] [3] [4] [5] [6] [7] No. Name Dam 63 Cummins Creek WS SCS 64 Brady Creek WS SCS Site 65 WS Laterals Northwest 66 Jim Ned Creek WS SCS 67 Jim Ned Creek WS SCS 68 Clear Creek WS SCS Site 62 Lake Dam [1] Creek Moss
Potential Dam Failures 2.4S.4-33 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.4S.4-2 500-year and SPF Inflow Peak Discharges at Selected Locations along the Colorado River (in cfs) Flood Event Buchanan Mansfield Tom Miller Bastrop Garwood Wharton Bay City 500-year 382,400 499,700 366,900 321,900 256,700 204,700 187,900 SPF 484,800 737,000 402,500 359,900 285,500 237,800 214,200 Source: Reference 2.4S.4-10
Table 2.4S.4-3 Breach Parameters for Buchanan and Mansfield Dams Breach Parameters Buchanan Dam Mansfield Dam Average Width of Breach (ft) 1470 1360 Breach Bottom Elevation (ft, MSL) 879.8 484 Breach Top Elevation (ft, MSL) 1,028.4 757 Side Slope of Breach 0 0 Breach Time to Failure (hrs) 0.1 0.1
2.4S.4-34 Potential Dam Failures Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.4S.4-4 Initial Estimation of Manning’s Roughness Coefficient n Values Assigned to the USGS NLCD Dataset USGS Classification Grid-Code Description n Value 11 Open water 0.03 21 Low intensity residential 0.07 22 High intensity residential 0.09 23 Commercial/industrial/transportation 0.10 31 Bare rock/sand/clay 0.04 32 Quarries/strip mines/gravel pits 0.035 41 Deciduous forest 0.095 42 Evergreen forest 0.085 51 Shrubland 0.08 71 Grasslands/herbaceous 0.04 81 Pasture/hay 0.045 82 Row crops 0.05 83 Small grains 0.055 85 Urban/recreation grasses 0.03 91 Woody wetlands 0.10 92 Emergent herbaceous wetlands 0.085 Source: Reference 2.4S.4-10
Potential Dam Failures 2.4S.4-35 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.4S.4-5 MCR Embankment Breach Parameters and Peak Discharge Based on Empirical Equations from Reference 2.4S.4-12d Parameter Equation Results 0.769 0.364 (1) Time to Failure (hrs) tf = 0.0179(0.0261(V*hw) ) 1.7 hours 0.32 0.19 (2) Average Breach Width (m) Bave = 0.1803 V hb 127 m (417 ft) 3 0.295 1.24 3 (3) Peak Flow (m /s) Qp = 0.607 V hw 1172.8 m /s (62,600 cfs)
Bave = average breach width hw = depth of water above breach in m = 50.9' – 29' = 21.9' = 6.7 m hb = the height of breach from the top of embankment in m = 66' – 29' = 37' = 11.3 m V = volume of water in the MCR between El. 29' and El. 50.9' in m3 = 188,400,000 m3 (152,700 ac-ft) (1) MacDonald and Langridge-Monopolis Time to Failure (2) Froelich’s Average Breach Width (3) Froelich’s Peak Flow
2.4S.4-36 Potential Dam Failures Rev. 12
STP 3 & 4 Final Safety Analysis Report
Table 2.4S.4-6 MCR Embankment Breach Outflow Hydrograph MCR Water Surface Elevation Time (hours) Flow (cfs) (ft) 0050.90 0.1 1,100 50.90 0.2 3,970 50.89 0.3 8,570 50.88 0.4 15,500 50.87 0.5 24,700 50.85 0.6 30,600 50.82 0.7 37,200 50.78 0.8 47,300 50.73 0.9 54,700 50.68 1.0 79,600 50.59 1.1 85,900 50.49 1.2 92,300 50.40 1.3 100,700 50.28 1.4 108,500 50.15 1.5 116,100 50.03 1.6 123,500 49.88 1.7 130,000 49.74 1.8 126,700 49.58 1.9 124,500 49.46 2.0 122,600 49.29 2.1 120,800 49.13 2.2 119,000 49.00 2.3 117,400 48.86 2.4 115,600 48.70 2.5 113,900 48.56 3 112,800 47.88 6 83,150 44.44 9 63,030 41.86 12 48,890 39.88 15 38,680 38.32 18 31,110 37.08 21 25,390 36.07 24 21,000 35.24 27 17,560 34.56 30 14,840 33.98
Potential Dam Failures 2.4S.4-37 Rev. 12
STP 3 & 4 Final Safety Analysis Report (ft) - 20 - 46.8 46.4 48.9 Peak Percent Flowrate Reservoir Difference at Time of Time at Water Level Water Qp (cfs) 157,70021 + 104,400 130,000 132,000128,200 + 1.5 - 1.1 (ft) Peak Flow Peak 448 179 619 Width Bottom Final Breach 18 18 Percent Difference (ft) 361 132 465 Peak Breach Bottom Width at Flowrate (ft) 446 310 380 Breach Width B 2.4 15.9 6.25 (hrs) Time to Peak 18 18 Selected for use with FLDWAV for use Selected Percent Difference (cfs) Peak 30,760 83,200 122,800 f Discharge t 1.4 2.0 1.7 (hours) Table 2.4S.4-6a Results of Sensitivity Analysis for Breach Parameters Breach for Analysis of Sensitivity Results 2.4S.4-6a Table Table 2.4S.4-6b Comparison of Manning’s n-value to BREACH Analysis Results of Manning’s 2.4S.4-6b Comparison Table f f 0.08 0.05 0.025 (n-value) Manning’s Coefficient Roughness Parameter to Fail Time Decreased t B Increased B Decreased Increased t Adopted
2.4S.4-38 Potential Dam Failures Rev. 12
STP 3 & 4 Final Safety Analysis Report 380 361 Peak Flowrate Peak Breach Bottom Breach Width at Time of at Time Width n n 0.085 0.040 0.100 0.100 0.040 0.030 0.035 0.013 0.100 0.085 0.012 Manning's Manning's 1.7 6.25 (hrs) Time to Peak 83,200 130,100 Peak Discharge (cfs) Discharge Peak Material Type Material Table 2.4S.4-7 Material Types and Associated Manning's Manning's Associated and Types Material 2.4S.4-7 Table Table 2.4S.4-6c Comparison of Results from BREACH and FLDWAV Models from BREACH and FLDWAV of Results Comparison 2.4S.4-6c Table Model FLDWAV BREACH Water Short Hard Building Building / High Drag Soft (VBW) Walls Barrier Vehicle Gravel Space Open Concrete Slab (Concrete) Road Channel Pipeline Artificial Sump
Potential Dam Failures 2.4S.4-39 Rev. 12
STP 3 & 4 Final Safety Analysis Report 1.9 14.4 18.7 (cfs/ft) per Unit Width Unit per Peak Discharge (ft MSL) (ft 3.8 4.4 0.4 (ft/s) Water Level at STP Site Water Peak Velocity (ft) Wave Run-up (ft) 3.8 4.8 4.25 Water Depth (ft) 38.2 37.6 38.8 Elevation Water Surface Water (ft MSL)(ft (ft) Setup Wind Dam Break Water Level Table 2.4S.4-7a Peak Flood Discharge per Unit Width at Safety-Related SSCs at Safety-Related Width Unit per Discharge Flood Peak 2.4S.4-7a Table Fetch AFetch 28.6 3.9 1.9 34.4 Table 2.4S.4-8 Estimated Water Levels due to Dam Break, Wind Setup, and Wave Run-up Wave Setup, and to Dam Break, Wind due Levels Water Estimated 2.4S.4-8 Table Location and Unit 4 Unit 4 UHS Block, South Unit 4 Power Unit Between Unit 3 Between NOTE: The examples TheNOTE: aboveBreach simulation. are based on the West
2.4S.4-40 Potential Dam Failures Rev. 12
STP 3 & 4 Final Safety Analysis Report Polk Trinity Smith Wood Cherokee Houston Harris San Jacinto ® Brazoria Walker Montgomery
Matagorda
Fort Bend Anderson do River do Madison Henderson Waller Van Zandt Grimes Leon Wharton Freestone Austin ufman Brazos Ka Calhoun Washington 15 Navarro Jackson Colorado Robertson Calhoun " S Burleson Limestone Ellis STP Site Boundary Site STP Dallas Lee Lavaca Falls Projection: Universal Transverse Mercator Zone: Zone 14 Horizontal Datum: North American 1927Datum Victoria Fayette Milam Hill 25 " S McLennan DeWitt Tarrant Bastrop Goliad 21 Johnson Bell " S Gonzales Caldwell Bosque " S Williamson 12 Hood Coryell " S Parker Travis Bee 1 Somervell Karnes Hays Guadalupe Wilson Hamilton Burnet 19 Live Oak Miles Erath 9 " S Comal 125 " S " S Lampasas Palo Pinto 4 Blanco Bexar Mills Atascosa Comanche 100 Kendall Llano
7 r
Eastland e Stephens San Saba
" S v i Brown
Gillespie R
Frio
75 o
Medina d
Mason a Coleman Kerr 10 27 13
r " S Bandera 18 " S " S o Callahan
l McCulloch Shackelford
" S o " S 28 C 50 " S 2 29 " S 24 " S Zavala Uvalde Real " S 31 Dimmit Kimble Jones Ta yl or Concho Menard " S 30 " S 25 23 Runnels " S 12.5 16 22 0 Fisher 6 Nolan " S " S Edwards Maverick " S Kinney 5 " S To m G ree n 3 LA Sutton LA AR AR Schleicher MO MO 14 Coke " S " S Scurry 17 Irion Mitchell " S ^ " S Sterling 8 OK 20 OK TX TX Val Verde 35 § ¨ ¦ Borden Crockett Howard (Capacity Greater than 10,000 AF) " S Reagan STP Site Glasscock 11 " S Basin Upstream of the STP 3 & 4 Site STP of the Basin Upstream 26 20 § ¨ ¦ Dawson Martin Upton Midland 25 Dam Locations along the Colorado River in Texas § ¨ ¦ Te rrel l 10 40 Pecos § ¨ ¦ § ¨ ¦ Gaines NM NM Ector Andrews Crane Brewster Figure 2.4S.4-1a Locations of Dams with Storage Capacity Over 10,000 AF in the Colorado River the Colorado River AF in Over 10,000 of Dams with Storage Capacity Locations Figure 2.4S.4-1a County Boundaries County STP Boundary STP Dam Locations Dam Centerline River Colorado Dam Location Key " S 1 MANSFIELD DAM 2 SIMON FREESE DAM 3 TWIN BUTTES DAM 4 BUCHANAN DAM 5 ROBERT LEE DAM 6 OC FISHER DAM 7 LAKE BROWNWOOD DAM 8 LAKE THOMASJB DAM DAM WIRTZ ALVIN 9 10 BRADY DAM DAM NATURAL 11 DAM MILLER TOM 12 COLEMAN13 DAM DAM CREEK CHAMPION 14 CEDAR15 CREEK DAM OAK16 CREEK DAM DAM LAKE 17 COLORADO CITY HORDS18 CREEK DAM 19 ROY INKS DAM DAM RESERVOIR COUNTY MITCHELL 20 21 DECKER CREEK DAM DAM NASWORTHY 22 23 BALLINGER MUNICIPAL LAKE DAM 24 ELM CREEK DAM 25 LAKE BASTROP DAM SULPHUR26 DAM SPRINGS DRAW 27 UPPER PECAN WS BAYOU SCS SITE 7 DAM DAM 17 SITE SCS WS CREEK BRADY 28 DAM 28 SITE SCS WS CREEK BRADY 29 DAM 31 SITE SCS WS CREEK BRADY 30 OLD31 LAKE CITY DAM WINTERS Legend
Potential Dam Failures 2.4S.4-41 Rev. 12
STP 3 & 4 Final Safety Analysis Report Tyler Cass Hardin Rusk Polk Harrison Liberty Angelina Galveston Gregg Chambers ® Upshur Camp Nacogdoches Galveston Trinity Smith San Jacinto San Cherokee Harris Wood Houston Brazoria Walker Montgomery Fort Bend Anderson Rains Madison Henderson Waller Van Zandt Grimes Leon Matagorda 32 Hunt Wharton " S Freestone Austin Brazos Calhoun Kaufman Washington Projection: Universal Transverse Mercator Zone: Zone 14 Horizontal Datum: North American 1927Datum Rockwall Navarro Jackson Robertson 63 Colorado Limestone Burleson Calhoun " S Ellis STP SiteSTP Boundary Dallas Lee Falls Lavaca Victoria Fayette Milam Hill Denton McLennan DeWitt Bastrop Tarrant Goliad Johnson Bell Gonzales " S Caldwell Bosque Williamson 51 Hood Coryell Parker Bee Somervell Karnes Travis Hays Guadalupe Wilson Miles Hamilton Jack Wise mal " S Burnet 125 Erath Live Oak 35 Co Lampasas Palo Pinto Blanco Bexar Mills Atascosa Comanche 100 McMullen Llano Young Kendall 48 40 Eastland Brown San Saba Stephens 59 " S " S Gillespie " S 42 75 " S 68 " S " S Frio 47 66 Medina " S La Salle 56 36 " S " S 58 Mason " S Kerr 61 " S 52 " S " S Bandera 54 Throckmorton " S 45 McCulloch 44 Callahan 50 " S Shackelford " S " S 43 " S Coleman 41 60 " S 34 " S " S 65 55 " S " S " S " S 49 37 67 64 " S Haskell 33 Zavala Dimmit Real Uvalde Kimble " S " S " S Jones 57 25 Menard 39 " S Ta yl or 50 38 Concho Runnels " S 12.5 46 0 Stonewall Fisher Nolan Edwards Maverick Kinney 53 LA LA Coke To m G ree n AR AR Sutton MO MO " S Schleicher Kent Scurry Mitchell Irion ^ Sterling OK OK " S TX TX 62 Val Verde 35 § ¨ ¦ Borden Crockett Howard Upstream of the STP 3 & 4 Site & 4 of the STP 3 Upstream Reagan STP Site Glasscock Lynn Garza (Capacity Between 5,000 and 10,000 AF) Martin Dawson 20 § ¨ ¦ Upton Midland 25 Dam Locations along the Colorado River in Texas § ¨ ¦ Te rrel l Te rry Pecos 10 40 § ¨ ¦ § ¨ ¦ Gaines Ector NM Andrews NM Crane Brewster County Boundaries County STP Boundary STP Dam Locations Dam Centerline River Colorado Dam Location Key " S Figure 2.4S.4-1b Locations of Dams with Storage Capacity of 5,000 AF to 10,000 AF in the Colorado River Basin Basin the Colorado River AF in AF to 10,000 of 5,000 Capacity with Storage of Dams Locations 2.4S.4-1b Figure 32 EAGLE LAKE DAM 33 BRADY CREEK WS SCS SITE 20 DAM DAM WS SCS 5A SITE LATERALS NORTHWEST 34 35 MAX DAM STARCKE 36 JIM NED CREEK WS SCS SITE 25 DAM 37 JIM NED CREEK WS SCS SITE 12E1 DAM 38 BALLINGER CITY LAKE DAM ELM39 CREEK WS NRCS 3 SITE REV CLEARDAM SITE CREEK WS SCS 6 40 41 JIM NED CREEK WS SCS SITE 21 DAM CLEARDAM SITE CREEK WS SCS 4 42 WS SITE SCS UPPER43 PECAN2 BAYOU DAM 44 BRADY CREEK WS SCS SITE 14 DAM 45 HOME CREEK WS SCS SITE 13 DAM CREEK46 VALLEY WS SCS SITE 1 DAM WS SITE SCS UPPER47 PECAN DAM 24 BAYOU BROWNWOOD 48 LATERALS WS SCSSITE DAM 3 WS SCS 1 SITE DAM LATERALS NORTHWEST 49 50 BRADY CREEK WS SCS SITE 32 DAM LONGHORN51 DAM 52 JIM NED CREEK WS SCS SITE 23 DAM ELM53 CREEK WS NRCS 7 SITE REV 54 HOME CREEK WS SCS SITEDAM 7A 55 JIM NED CREEK WS SCS SITE 12 DAM CREEK56 MUKEWATER WS SCS SITE DAM 10A ELM57 CREEK LAKE DAM CLEARDAM SITE CREEK WS SCS 3 58 59 SE LATERALS WS SCS SITE 7 DAM 60 BRADY CREEK WS SCS SITE 21 DAM WS SITE SCS UPPER61 PECAN DAM 12 BAYOU 62 MOSS CREEK LAKE DAM DAM 1 SITE SCS WS CUMMINS CREEK 63 64 BRADY CREEK WS SCS SITE 36 DAM WS SCS 2 SITE DAM LATERALS NORTHWEST 65 66 JIM NED CREEK WS SCS SITEDAM 26A 67 JIM NED CREEK WS SCS SITE 19 DAM CLEARDAM SITE CREEK WS SCS 1 68 Legend
2.4S.4-42 Potential Dam Failures Rev. 12
STP 3 & 4 Final Safety Analysis Report
Figure 2.4S.4-2 Model Cross Section at Buchanan Dam
Figure 2.4S.4-3 Model Cross Section at Mansfield Dam
Potential Dam Failures 2.4S.4-43 Rev. 12
STP 3 & 4 Final Safety Analysis Report
Hamilton Freestone Mills McLennan Limestone Coryell Leon Falls Houston Lampasas
San Saba Killeen Temple Bell Robertson Madison San Saba
Milam Burnet Walker ") BUCHANAN DAM Williamson Brazos College Station--Bryan Grimes Llano Burleson
MANSFIELD DAM ") Austin Montgomery Travis Lee
Blanco Washington
Bastrop Hays Waller Harris Kendall Austin Fayette Caldwell Houston Comal
Colorado Guadalupe Fort Bend Garwood at San Antonio RS 408861 Gonzales Bexar Lavaca
Wharton RS 253036 near Wilson Wharton 253036 Brazoria DeWitt RS 166521.6 at Bay City 166521.6 Jackson Matagorda Karnes Victoria STP Site Atascosa Boundary Victoria ! !
! !
!
! ! !
!
!
Calhoun ! Goliad ! !
!
Calhoun
McMullen Live Oak Bee Refugio Calhoun ® Aransas
04.5 9 18 27 36 45
Miles
Figure 2.4S.4-4 Locations of Model Cross Sections in the Dam Break Analysis
2.4S.4-44 Potential Dam Failures Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.4S.4-5 Model River Cross Section at About 365 River Miles Upstream of the GIWW Upstream of Miles River About 365 Section at Cross Model River Figure 2.4S.4-5 Note: Between Buchanan and Mansfield Dams and about 49.6 River Miles Upstream of Mansfield Dam. of Mansfield Miles Upstream River 49.6 about Dams and Mansfield and Buchanan Note: Between
Potential Dam Failures 2.4S.4-45 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.4S.4-6 Model River Cross Section at About 163.5 River Miles Upstream of the GIWW GIWW of the Upstream Miles River at About 163.5 Section River Cross Model 2.4S.4-6 Figure Note: Downstream of Mansfield Dam and about 153 miles Upstream of STP 3 & 4 Site. Upstream miles 153 of about Dam Note: Downstream and Mansfield
2.4S.4-46 Potential Dam Failures Rev. 12
STP 3 & 4 Final Safety Analysis Report About 10.5 River Miles Upstream of the GIWW Upstream River Miles About 10.5 Figure 2.4S.4-7 Model River Cross Section at Cross Model River Figure 2.4S.4-7 Note: Near the STP site.
Potential Dam Failures 2.4S.4-47 Rev. 12
STP 3 & 4 Final Safety Analysis Report Model Boundary at about 0.9 River Miles Upstream of the GIWW of the Upstream Miles 0.9 River at about Model Boundary Figure 2.4S.4-8 Model River Cross Section at Downstream at Downstream Section River Cross Model 2.4S.4-8 Figure
2.4S.4-48 Potential Dam Failures Rev. 12
STP 3 & 4 Final Safety Analysis Report Flow
Stage
Legend Flow (cfs) Flow 2000000 1800000 1600000 1400000 1200000 1000000 800000 600000 400000 Final Report Safety Analysis 01Feb2000 01 27 22 Time 17 Jan2000 lected arbitrarily. 12 Plan: One n20 River: Colorado Reach: 1 RS: 89146.04 1 RS: Reach: Colorado River: n20 One Plan: 07 l start date was se date l start 30 28 26 24 22 20
Figure 2.4S.4-9 Based Case Flood and Stage Hydrographs at the STP 3 & 4 Site & at the STP 3 Stage Hydrographs and Case Flood Based Figure 2.4S.4-9 Stage (ft) Stage Note: Vertical Datum is NAVD 88; mode Datum is NAVD Note: Vertical
Potential Dam Failures 2.4S.4-49 Rev. 12
STP 3 & 4 Final Safety Analysis Report Flow
Stage
Legend Flow (cfs) Flow 2200000 2000000 1800000 1600000 1400000 1200000 1000000 800000 600000 400000 Final Report Safety Analysis 01Feb2000 01 27 22 Time 17 Jan2000 lected arbitrarily. 12 Plan: Dam Break n0 River: Colorado Reach: 1 RS: 89146.04 1 Reach: Colorado River: n0 Break Dam Plan: 07 l start date was se date l start
28 26 24 22 20 18 Stage (ft) Stage STP 3 & 4 Site at the Stage Hydrographs Flood and Case Sensitivity Figure 2.4S.4-10 Note: Vertical Datum is NAVD 88; mode Datum is NAVD Note: Vertical
2.4S.4-50 Potential Dam Failures Rev. 12
STP 3 & 4 Final Safety Analysis Report Ground Legend Crit Max WMax S Crit WS Max WS Max WS 2500000
Final Report SafetyAnalysis
Buchanan Dam Dam Buchanan Buchanan
2000000
Mansfield Dam Dam Mansfield Mansfield 1500000 Main Channel Distance (ft) Distance Channel Main 1000000 (Vertical Datum in NAVD 88) in NAVD Datum (Vertical
500000
Bay City City Bay Bay
STP Site Site STP STP 0 0 800 600 400 200
-200 1200 1000
Elevation (ft) (ft) Elevation Elevation Figure 2.4S.4-11 Base Case Simulated Maximum Dam Break Surface Profiles from Buchanan ft upstream of GIWW Surface Profiles from Buchanan Dam to 4,600 Dam Break Maximum Base Case Simulated 2.4S.4-11 Figure
Potential Dam Failures 2.4S.4-51 Rev. 12
STP 3 & 4 Final Safety Analysis Report Ground Legend Crit Max WS Max Crit WS Max WS Max WS 2500000
Final Report Safety Analysis
Buchanan Dam Dam Buchanan Buchanan
2000000
Mansfield Dam Dam Mansfield Mansfield 1500000 GIWW Main Channel Distance (ft) Distance Channel Main 1000000
500000
Bay City City Bay Bay
STP Site Site STP STP 0 0 800 600 400 200
-200 1200 1000
Elevation (ft) (ft) Elevation Elevation Figure 2.4S.4-12 Sensitivity Case Simulated Maximum Dam Break Surface Profiles from Buchanan Dam to 4600 ft Upstream of ft Upstream of to 4600 Dam from Buchanan Surface Profiles Break Dam Maximum Simulated Case Sensitivity 2.4S.4-12 Figure Note: Vertical Datum in NAVD 88. Datum in NAVD Vertical Note:
2.4S.4-52 Potential Dam Failures Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.4S.4-13 Outflow Rates Experienced from Breached Dams (Reference 2.4S.4-12e) (Reference Dams from Breached Experienced Outflow Rates 2.4S.4-13 Figure
Potential Dam Failures 2.4S.4-53 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.4S.4-13a Breach Width Development for Different n-values Development Width Breach Figure 2.4S.4-13a
2.4S.4-54 Potential Dam Failures Rev. 12
STP 3 & 4 Final Safety Analysis Report dth Development from BREACH analysis dth Development Figure 2.4S.4-13b Breach Bottom Wi Figure
Potential Dam Failures 2.4S.4-55 Rev. 12
STP 3 & 4 Final Safety Analysis Report BREACH and FLDWAV Outflow Hydrographs Figure 2.4S.4-13c Comparison of Figure 2.4S.4-13c Comparison
2.4S.4-56 Potential Dam Failures Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.4S.4-14 Units 3 and 4 Site Grading Plan Site Grading 3 and 4 Units Figure 2.4S.4-14
Potential Dam Failures 2.4S.4-57 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.4S.4-15 STP Site Layout 2.4S.4-15 Figure
2.4S.4-58 Potential Dam Failures Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.4S.4-16 Two-Dimensional View of Developed 2-D Grid with an East Breach 2-D Grid with an Developed of View Two-Dimensional Figure 2.4S.4-16
Potential Dam Failures 2.4S.4-59 Rev. 12
STP 3 & 4 Final Safety Analysis Report Figure 2.4S.4-17 Two-Dimensional View of Developed 2-D Grid with a West Breach a West with 2-D Grid View of Developed Two-Dimensional 2.4S.4-17 Figure
2.4S.4-60 Potential Dam Failures Rev. 12 STP 3 & 4 Final Safety Analysis Report Figure 2.4S.4-18 Assigned Material Types of Developed 2-D Grid Developed of Material Types Assigned Figure 2.4S.4-18
Potential Dam Failures 2.4S.4-61 Rev. 12 STP 3 & 4 Final Safety Analysis Report Figure 2.4S.4-19 Locations for RMA2 Modeling Results Modeling for RMA2 Locations 2.4S.4-19 Figure
2.4S.4-62 Potential Dam Failures Rev. 12 STP 3 & 4 Final Safety Analysis Report Figure 2.4S.4-20 Time-Dependent Water Surface Elevations Associated with East Breach Scenario Breach East with Associated Surface Elevations Water Time-Dependent 2.4S.4-20 Figure
Potential Dam Failures 2.4S.4-63 Rev. 12 STP 3 & 4 Final Safety Analysis Report Figure 2.4S.4-21 Time-Dependent Water Surface Elevations Associated with West Breach Scenario Breach with West Associated Elevations Water Surface Time-Dependent Figure 2.4S.4-21
2.4S.4-64 Potential Dam Failures Rev. 12 STP 3 & 4 Final Safety Analysis Report
breach) Figure 2.4S.4-21a Peak Water Surface Elevations Associated with East Breach Scenario (at time = 1.75 hours after initiation of after initiation 1.75 hours (at time = Scenario Breach with East Associated Elevations Surface Water Peak Figure 2.4S.4-21a
Potential Dam Failures 2.4S.4-65 Rev. 12 STP 3 & 4 Final Safety Analysis Report
breach) Figure 2.4S.4-21b Peak Water Surface Elevations Associated with West Breach Scenario (at time = 1.75 hours after initiation of initiation hours after time = 1.75 Scenario (at Breach with West Associated Elevations Surface Peak Water 2.4S.4-21b Figure
2.4S.4-66 Potential Dam Failures Rev. 12 STP 3 & 4 Final Safety Analysis Report Figure 2.4S.4-21c Peak Velocities Associated with East Breach Scenario (at time = 1.75 hours after initiation of breach) after initiation hours time = 1.75 (at Scenario with East Breach Associated Velocities Peak 2.4S.4-21c Figure
Potential Dam Failures 2.4S.4-67 Rev. 12 STP 3 & 4 Final Safety Analysis Report Figure 2.4S.4-21d Peak Velocities Associated with West Breach Scenario (at time = 1.75 hours after initiation of breach) of initiation hours after = 1.75 (at time Scenario Breach with West Associated Velocities Peak Figure 2.4S.4-21d
2.4S.4-68 Potential Dam Failures Rev. 12 STP 3 & 4 Final Safety Analysis Report Figure 2.4S.4-21e Time-Dependent Velocities Associated with East Breach Scenario Breach with East Associated Velocities Time-Dependent Figure 2.4S.4-21e
Potential Dam Failures 2.4S.4-69 Rev. 12 STP 3 & 4 Final Safety Analysis Report Figure 2.4S.4-21f Time-Dependent Velocities Associated with West Breach Scenario Breach with West Associated Velocities Time-Dependent 2.4S.4-21f Figure
2.4S.4-70 Potential Dam Failures Rev. 12 STP 3 & 4 Final Safety Analysis Report
Figure 2.4S.4-21f1 Selected Fan Areas Associated with East Breach Scenario (top) and West Breach Scenario (bottom)
Potential Dam Failures 2.4S.4-71 Rev. 12 STP 3 & 4 Final Safety Analysis Report Figure 2.4S.4-21i Stream System around STP Site System Stream Figure 2.4S.4-21i
2.4S.4-72 Potential Dam Failures Rev. 12 STP 3 & 4 Final Safety Analysis Report Inundation at Safety-Related SSCs at Safety-Related Inundation Figure 2.4S.4-21j Breach Outflow and Flood Elevation to Determine Duration of to Determine Flood Elevation Outflow and Breach 2.4S.4-21j Figure
Potential Dam Failures 2.4S.4-73 Rev. 12 STP 3 & 4 Final Safety Analysis Report Figure 2.4S.4-22 Fetch Directions and Length and Directions Fetch 2.4S.4-22 Figure
2.4S.4-74 Potential Dam Failures Rev. 12
STP 3 & 4 Final Safety Analysis Report
2.4S.5 Probable Maximum Surge and Seiche Flooding This section addresses the SRP Subsection 2.4.5 Acceptance Criteria Limits from the reference ABWR DCD Tier 2, Table 2.1-1, which states that the probable maximum surge and seiche flooding level should be 30.5 cm (i.e., 1 ft) below site grade. The nominal plant grade for STP 3 & 4 is 34 feet mean sea level (MSL). The surge and seiche level resulting from a probable maximum hurricane is estimated to be 31.1 ft MSL, meeting the specific DCD flood level criterion. Subsection 2.4S.5 develops the hydrometeorological design basis for considering potential hazards to the safety- related facilities due to the effects of probable maximum surge and seiche. Flood analyses for STP 3 & 4 indicated that the PMH would not be the controlling event for the design basis flood elevation of the STP site as the postulated dam failure scenarios discussed in Subsection 2.4S.4 would result in the highest flood level.
2.4S.5.1 Probable Maximum Winds and Associated Meteorological Parameters The hydrometeorological conditions that would produce the Probable Maximum Storm Surge (PMSS) along the Texas Coast coincide with the probable maximum meteorological winds (PMMW) from the probable maximum hurricane (PMH). The PMH is described by Reference 2.4S.5-1 (p. 2) as “a hypothetical steady state hurricane having a combination of values of meteorological parameters that will give the highest sustained wind speed that can probably occur at a specified coastal location.” The meteorological parameters that give the highest sustained wind speed are known as the PMH windfield (Reference 2.4S.5-1, p. 2). These parameters include the peripheral pressure (pn), central pressure (po), radius of maximum winds (R), forward speed (T), track direction (θ), and inflow angles (ϕ) of the hurricane winds. The initial PMMW parameters are obtained based on identification of the milepost location along the Gulf Coast (Reference 2.4S.5-1, p. 4). Data from historical storms have been used to establish envelope (i.e., upper and lower boundary) conditions for determining the radius of maximum winds and the forward speed (Reference 2.4S.5-1).
The PMH PMMW conditions as determined from Reference 2.4S.5-1 are listed in Table 2.4S.5-2. The peripheral pressure is 30.12 in. Hg. The central pressure is 26.19 in. Hg. Therefore, the PMH P was assumed to be 3.93 in. Hg, or 133.07 millibars. The radius of maximum winds had upper and lower limits of 5 and 21 nautical miles, respectively. The forward speed had upper and lower limits of 6 and 20 knots, respectively.
2.4S.5.2 Surge and Seiche Water Levels The technical definition of a storm surge is “an abnormal rise of water generated by a storm, over and above the predicted astronomical tide” (Reference 2.4S.5-2, p. 1). The storm surge coinciding with a hurricane typically lasts several hours and affects about one hundred miles of coastline (Reference 2.4S.5-2, p. 1). The setup of the storm surge from the hurricane occurs due to the action of surface wind stress and due to atmospheric pressure reduction. As shown in Figure 2.4S.5-1, the storm surge is the sum of several components, including initial sea level rise, setup due to astronomical forces, setup due to atmospheric pressure reduction, setup due to wind stress effects, and setup due to breaking waves (Reference 2.4S.5-3, p. 20). The initial sea level rise is derived from tide gauge data. Reported tide gauge data in the general area of STP
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3 & 4 are available for Port Isabel, Texas, and Freeport, Texas. A site-specific estimate of the initial sea level rise of 2.4 ft. was selected for the coast near STP 3 & 4 using the Freeport, Texas station (Reference 2.4S.5-4, p. 1.59-48). The ten percent exceedance of the astronomical high tide is defined by Reference 2.4S.5-5 (p. 19) as “the 10% exceedance high tide is the high-tide level that is equaled or exceeded by 10% of the maximum monthly tides over a continuous 21-[year] period.” As with the initial rise, an estimate of 2.2 feet was selected as the ten percent exceedance high tide based on the reported value for Freeport, Texas (Reference 2.4S.5-4, p. 1.59-48).
2.4S.5.2.1 Historic Storm Surge Events STP 3 & 4 is located over fifteen miles inland from the Gulf Coast (Figure 2.4S.5-2). A list of hurricanes that have impacted the Texas Coast from 1900 to 2005 is shown in Table 2.4S.5-1. Figure 2.4S.5-3 and Figure 2.4S.5-4 depict hurricane tracks that have impacted the Texas Coast from 1852 to 2006 (Reference 2.4S.5-6). A frequency analysis of hurricanes occurring between 1900 and 1963 along the Gulf Coast of Texas noted that “dangerous and destructive tropical cyclones (hurricanes) can be expected to cross the Texas Coast on the average of about once every three years” (Reference 2.4S.5-7, p. 1). Table 2.4S.5-1 indicates the frequency of hurricanes impacting the Texas Coast between 1900 and 2005 is still about once every three years.
As the Texas coast has a relatively gentle land slope with low-lying coastal elevations, the storm surge resulting from these hurricanes is capable of flooding significant land areas. For example, Reference 2.4S.5-8 (p. 40) states that “reported surges were 16.6 feet above MSL at Port Lavaca, 14.5 feet above MSL at Port O’ Connor, 15.2 feet above MSL at Matagorda, and 14.8 feet above MSL on the upper Houston Ship Channel. A high water line varying from 15.7 to 22 feet above MSL, established from debris near the head of Lavaca Bay, probably included the undetermined effects of wave setup and runup.” The peak storm surge elevation near STP 3 & 4 was about 16 feet MSL (Reference 2.4S.5-8, p. 46).
2.4S.5.2.2 Storm Surge Analysis Three different approaches were used to estimate the storm surge at STP 3 & 4. The first approach was based on use of the computer program “Quasi Two-Dimensional Open Coast Storm Surge,” known as SURGE (Reference 2.4S.5-3). This approach included two steps to estimate the PMSS water surface elevation near STP 3 & 4. First, SURGE was used to estimate the PMSS water surface elevation at the coast near Matagorda, Texas (Figures 2.4S.5-1 and 2.4S.5-5). Second, the PMSS water surface elevation was used as a boundary condition for a backwater calculation using a calibrated and modified model developed by Halff Associates, Inc., for the Colorado River (References 2.4S.5-9 and 2.4S.5-10).
The second approach was based on the use of the numerical model “Sea, Lake, and Overland Surges from Hurricanes” (SLOSH) (Reference 2.4S.5-2). SLOSH was used to obtain estimates of water surface elevation near STP 3 & 4 due to a hypothetical Category 5 ‘maximum of maximum’ (MOM) hurricane impacting the Matagorda Bay region. The MOM is the maximum of the composite of the maximum envelope of water (MEOW), which incorporates all of the peak values for a hurricane of a particular
2.4S.5-2 Probable Maximum Surge and Seiche Flooding Rev. 12
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category, speed, and landfall direction. Therefore, it should be noted that a graphical presentation or hydrograph of the SLOSH output is not available since the MEOW scenarios are composites of numerous runs and are therefore not time dependent for individual cells. Rather, the SLOSH MOM only yields the peak water surface elevations for each cell by hurricane category (i.e., Category 1, Category 2, Category 3, Category 4, and if available, Category 5). It is also noted that SLOSH does not incorporate the ten percent exceedance of the astronomical high tide or a user- specified initial sea-level rise like SURGE (Reference 2.4S.5-2). SLOSH just assumes a constant initial tide elevation of 2 feet above MSL.
The third approach used to predict the PMSS used the numerical Advanced Circulation (ADCIRC) Model, a hydrodynamic circulation model that simulates water level and current over an unstructured gridded domain. The ADCIRC model was selected to validate the results obtained with first two approaches in recognition that that "current best practices" for predicting storm surge are evolving rapidly due to the very high level of interest and active involvement of the Federal Emergency Management Agency (FEMA), the National Oceanic and Atmospheric Administration (NOAA), and the US Army Corps of Engineers (USACE). Associated supporting research has been ongoing at several major universities. These ongoing efforts have resulted in major improvements to the more complex multidimensional computer models used to predict storm surge. Additionally, digital elevation maps based on Light Detection and Ranging (LIDAR) for use with ADCIRC were recently made available for a wider area, including the STP site. The LIDAR based maps improve the accuracy and resolution of the topographic grid, an important input to the computer models, such as ADCIRC, that predict storm surge. Assumptions and initial conditions used with the ADCIRC model were, to the maximum extent possible, consistent with the assumptions and initial conditions used with the SLOSH model.
2.4S.5.2.3 Storm Surge Analysis with SURGE and HEC-RAS 2.4S.5.2.3.1 Storm Surge Analysis with SURGE SURGE calculates the storm surge water surface elevation near the open coast using as input the PMH windfield characteristics, the offshore bathymetry and a bottom friction factor (References 2.4S.5-3 and 2.4S.5-8). SURGE is based on the solution of a volume-transport form of the two-dimensional hydrodynamic equations over a fixed boundary (Reference 2.4S.5-3). The code implements a simple finite step method for discrete increments of space and time along a single Cartesian axis. The bathymetry used in SURGE was based on the simplifying assumption that the bathymetric contours near the Gulf Coast are parallel to the shoreline. The distance from shore is based on developing a traverse from the coast to where the depth of the Gulf of Mexico is approximately 600 ft (Reference 2.4S.5-4, p. 1.59-43). Based on this assumption, the bathymetry was aligned along a traverse line near Matagorda and STP 3 & 4 (Figure 2.4S.5-5). The bottom profile along the traverse was obtained from the National Oceanic and Atmospheric Administration coastal bathymetry map from Galveston to the Rio Grande (Reference 2.4S.5-11). The hurricane center (i.e., the hurricane eye) was placed to the west of the traverse line in accordance with the geometry of the radius of the maximum wind and the inflow angle as described in
Probable Maximum Surge and Seiche Flooding 2.4S.5-3 Rev. 12
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Reference 2.4S.5-3 (p. 32). As the probable maximum wind occurs along this traverse, the surge heights calculated along the traverse result in a prediction of the PMSS water surface elevation.
While the windfield characteristics and bottom topography can be derived from References 2.4S.5-1 and 2.4S.5-11, respectively, the bottom friction factor is not known a priori and needs to be calibrated. This calibration is based on iteratively testing the friction factor to match previously observed overland storm surge elevations with predicted model values. Calibration of the bottom friction factor for the methodology described in SURGE (Reference 2.4S.5-3) is summarized by Reference 2.4S.5-8 (p. 119). PMMW data were obtained for the 1949 Hurricane and Hurricane Carla (Reference 2.4S.5-8, p. 35-36 and p. 36-43, respectively), and used to estimate storm surge water surface elevations along the Galveston and Freeport, Texas traverses (Figure 2.4S.5-5). The estimated storm surge heights were then compared with observed values. As stated on p. 118 of Reference 2.4S.5-8, “the computed surge hydrograph of the Hurricane of 1949 at Galveston showed poor correlation to the recorded surge hydrograph; this may be due to lack of wind data for this traverse. A fair correlation was obtained for the Freeport traverse.” From the same page, “good results were obtained using Hurricane Carla data for the Galveston traverse which provided most of the desired conditions for an open-coast station. Good results were obtained for the Freeport traverse.” The calibration data indicated that a bottom friction factor of 0.003 produced the closest match between the observed and predicted storm surge elevations. A friction factor of 0.003 was also adopted for the PMSS estimate for Freeport, Texas (Reference 2.4S.5-4, p 1.59-48). Subsequently, a bottom friction factor of 0.003 was adopted for estimating the PMSS with the SURGE code for STP 3 & 4.
A wind stress correction factor of 1.1 was included in the storm surge calculations. This factor accounts for the effect of rainfall on the sea surface stress, with Reference 2.4S.5-12 (p. 148) stating that “since 10-20% of the [drops] momentum is lost to the air, and since in some cases the total momentum transferred to the surfaces by the [drops] can be comparable to that transferred by the air, the stresses introduced into the air by the drops can be 10-20% of the wind stress.”
The SURGE program was used to calculate the storm surge for four scenarios that represent limiting combinations of the radius of maximum winds and hurricane forward speed. The four scenarios are shown in Table 2.4S.5-3. The governing PMMW characteristics for each scenario were derived from Reference 2.4S.5-3. The lower and upper limits of the radius of maximum winds used were 5 and 21 nautical miles, respectively. The lower and upper limits of the hurricane forward speed used were 6 and 20 knots, respectively. The maximum storm surge height from the four scenarios occurred for a hurricane with a radius of maximum winds of 21 nautical miles and a forward speed of 20 knots. The estimated peak water surface elevation of the storm surge was 18.79 feet mean low water (MLW). This value is equivalent to 18.11 feet MSL considering the datum shift of 0.68 feet from MLW to mean sea level (MSL) at Freeport, Texas (Reference 2.4S.5-13). To account for the long-term sea level rises due to global climate change, it is assumed that the historical mean sea level trend at Freeport, Texas of 5.87 mm/year or 1.93 feet/century, with a standard error of 0.74
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mm/yr, from 1954 to 1999 (Reference 2.4S.5-13) will continue. Therefore, including sea-level rise over the next century, the PMSS at the Gulf coast for the most severe SURGE scenario is estimated as 20.04 feet MSL.
With respect to the assumption of the MSL datum (or NGVD 29) shift relative to actual mean sea level from tidal measurements, it should be noted that the Freeport, Texas, tide gauge does not have a published or official NGVD29 orthometric height mark. Since the one mark that does exist suggests the difference between MSL (or NGVD 29) to actual mean sea level is small (i.e., within ±0.2 ft of the Mean Lower-Low Water datum), the shift to MSL (or NGVD 29) should be considered as an approximation of the actual value.
2.4S.5.2.3.2 Storm Surge Analysis with Halff HEC-RAS Hydraulic Model A modified version of the Halff HEC-RAS hydraulic model (i.e., Reference 2.4S.5-10) was used to estimate the water surface elevation at STP 3 & 4 based on a backwater calculation on the Colorado River using the storm surge water surface elevation near the open coast as the downstream boundary condition. The Halff HEC-RAS model was developed for Halff’s flood damage evaluation study and is discussed extensively in Subsection 2.4S.3. To be on the conservative side, however, the floodplain- extension used in HEC-RAS model of Subsection 2.4S.3 was not adopted in estimating the storm surge at STP 3 & 4. Little Robbins Slough near the STP site, shown in Figure 2.4S.5-8, is a shallow multi-channel slough that joins Robbins Slough, a brackish marsh, which eventually drains to the Gulf Intracoastal Waterway. With the PMSS, it would be completely submerged and drowned out, thereby resulting in negligible water surface slopes for the backwater calculation. Therefore, the Colorado River is used for the PMSS backwater calculation in order to generate a bounding PMSS water level at STP 3 & 4.
The model used for Subsection 2.4S.5 is a truncated version of the reach between Bay City to Matagorda Bay. Bay City to Matagorda Bay covers a reach length of about 24 miles and includes two bridge crossings, one at the Missouri Pacific Railroad (RS 1350+15.3) and another at the FM 521 roadway (RS 843+40.0). The upstream-most cross-section in the Halff model from Bay City to Matagorda Bay is located at the Bay City USGS gauging station (RS 1665+21.6). The downstream-most cross-section (RS 383+64.5) in the model is located about 4,600 ft upstream of the intersection of Lower Colorado River and the Intracoastal Waterway (RS 337+90) (see Volume II-C, Chapter 6, Table I-1 of Reference 2.4S.5-10). For this study, only thirty cross-sections were used, between river stations (RS) 383+64.5 and RS 964+99.7. A truncated version of the model was used since the cross-sections above RS 964+99.7 feet are not needed as flow in the Colorado River is subcritical (Subsection 2.4S.3). However, unlike Subsection 2.4S.3, the cross-sectional geometries between stations 383+64.5 and 964+99.7 feet were not altered from the original Halff HEC-RAS model (Reference 2.4S.5-10), i.e., no extensions into the floodplain areas. This approach provides a more conservative estimate of the water surface elevation at STP 3 & 4.
The peak water surface elevation at STP 3 & 4 (i.e., RS 891+46) resulting from the storm surge was assumed to coincide with a 100-year flood event of 98,751 cfs
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(Reference 2.4S.5-10, p. A13-Matagorda-8). Using the truncated HEC-RAS model described above, the water surface elevation near STP 3 & 4 was calculated to be 24.29 feet MSL (Figure 2.4S.5-6). The SURGE estimate of 24.29 feet MSL is less conservative than the SLOSH estimate for STP 3 & 4, which is discussed in Section 2.4S.5.2.4.
2.4S.5.2.4 Storm Surge Analysis with SLOSH and ADCIRC 2.4S.5.2.4.1 Storm Surge Analysis with SLOSH The second approach for the estimation of the maximum storm surge at STP 3 & 4 used output from the computer model “Sea, Lake, and Overland Surges (SLOSH)” (Reference 2.4S.5-2). SLOSH was developed by the National Oceanic and Atmospheric Administration (NOAA) and evolved from a simpler model known as the “Special Program to List Amplitudes of Surges from Hurricanes (SPLASH).” SLOSH is a two-dimensional finite difference code that uses an adaptive curvilinear grid for regions along the Gulf and Atlantic coasts. SLOSH assumes uniform friction to solve the equations of motion for reference basins along the Gulf of Mexico and Atlantic Ocean coast. Unlike SURGE, SLOSH can estimate water surface elevations due to the storm surge for both the open coast and on land.
The validity of the SLOSH model has been demonstrated and documented extensively (Reference 2.4S.5-14). While the model validity varies by station, the mean error of the SLOSH predictions for 523 observations within the Gulf of Mexico was reported as 0.09 m (0.29 ft) with a standard deviation of 0.61 m (2.0 ft) (Reference 2.4S.5-14, p. 1410). The maximum difference between the predicted storm surge elevations and the measured storm surge elevations was 2.69 m (8.83 ft) (Reference 2.4S.5-14, p. 1410). For Freeport, Texas, the model predictions replicate the observed surge elevations of approximately 11 ft MLW (10.32 ft MSL) within the mean error during Hurricane Carla (1961) (Reference 2.4S.5-2, p. 61).
The SLOSH MOM scenario predicts that STP 3 & 4 is dry for Category 1 through Category 5 hurricanes (Figure 2.4S.5-7). However, an estimate of the PMH PMSS using SLOSH can be made by using cells near STP 3 & 4 in the Lower Colorado River (Figure 2.4S.5-7). With respect to the windfield conditions, the SLOSH MOM estimate is based on a hurricane with a forward speed of 15 mph (13.03 knots) and a northwest wind. Since the Category 5 hurricane is a less severe scenario than the PMH, the SLOSH estimate needs to be adjusted to be comparable to the SURGE results. By assuming an extrapolation based on the maximum water surface elevation of a MOM Category 2 hurricane through a MOM Category 5 hurricane, the SLOSH PMH PMSS was estimated to be 27.2 ft MSL. Additionally, since the SLOSH model assumes an initial condition of 2 feet MSL for Matagorda Bay, its storm surge estimate needs to be adjusted to be comparable to the SURGE results. First, to account for the long-term sea level rises due to global climate change, it is assumed that the historical mean sea level trend at Freeport, Texas of 5.87 mm per year or 1.93 feet per century, with a standard error of 0.74 mm/yr, from 1954 to 1999 (Reference 2.4S.5-13) will continue. Second, the 2 ft MSL tide assumed by SLOSH needs to be differenced with the 10% exceedance of the astronomical high tide of 2.2 feet MLW (1.52 feet MSL) and the
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initial water rise of 2.4 feet. Therefore, the PMSS at STP 3 & 4 predicted by SLOSH, with the sea level adjustments, is 31.1 feet MSL. This value is more conservative than the SURGE estimate of 24.29 feet MSL at STP 3 & 4.
2.4S.5.2.4.2 Storm Surge Analysis with ADCIRC The third approach used for the estimation of the maximum storm surge at STP 3 & 4 used output from the computer model Advanced Circulation (ADCIRC). Specifically, version 49 of ADCIRC-2DDI, the two-dimensional, depth-integrated implementation of the ADCIRC coastal ocean model, was used to perform the hydrodynamic computations used to estimate storm surge levels at the site. This model uses depth-integrated equations of mass and momentum conservation subject to incompressibility, Boussinesq, and hydrostatic pressure approximations (References 2.4S.5-15 through 2.4S.5-18). ADCIRC is linked to a computer program called SWAN that calculates the wave-induced setup in addition to the wind-induced setup calculated by ADCIRC. SWAN is a third-generation wave model developed by Delft University of Technology. SWAN computes random, short-crested wind-generated waves in coastal regions and inland waters (Reference 2.4S.5-19). The unstructured-mesh SWAN spectral wave model and the ADCIRC shallow-water circulation model have been integrated into a tightly coupled SWAN + ADCIRC model. Hurricane waves and storm surge as estimated by the coupled SWAN + ADCIRC model have been validated for Hurricane Katrina and Hurricane Rita, demonstrating the importance of inclusion of the wavecirculation interactions.
The Federal Emergency Management Agency (FEMA) certified ADCIRC for use in performing storm surge analyses as part of their program for developing Flood Insurance Rate Maps (FIRMs) along coastal areas of the United States. This model is the standard coastal model used by the Unites States Army Corps of Engineers (USACE). In addition to USACE projects, it is used the National Oceanic and Atmospheric Administration (NOAA) and the Naval Research Laboratory (NRL).
The ADCIRC model as applied to the STP analysis underwent an extensive flood level evaluation process to validate it over a range of conditions to ensure that the flow physics of the system were accurately characterized. The set of validation storms specific to the Texas coastal areas included Hurricanes Carla (1961), Celia (1970), Allen (1980), Alicia (1983), Bret (1999), Rita (2005), and Ike (2008). Hurricanes Rita and Ike were particularly useful storms for validation because of the large degree of surge they produced, and the accurate measurements of wind, atmospheric pressure, waves, and surge levels that exist for these two storms.
Topography for Texas was obtained predominantly using 10-meter LIDAR data supplied by FEMA. Light Detection and Ranging (LIDAR) is a remote sensing system used to collect topographic data. All topographic and bathymetric data were spatially averaged to the local mesh scale. The topographic data were applied to the grid by searching for all LIDAR points within a rectangle defined by the average distance from the node for which we are assigning a topographic value to the connected nodes. The topographic grid used for the ADCIRC analysis at STP accounts for pronounced vertical features with small horizontal scales relative to the grid scale. While features
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such as barrier islands and riverbanks are generally well resolved in grids with resolutions down to about 100 feet, features like levees, floodwalls, railroads, and raised highways will not be sufficiently well resolved with 100-foot grid resolution. Frequently, these small-scale features can be significant horizontal obstructions to flow causing water to rise or be diverted elsewhere, which proved to be the case at STP. These obstructions must therefore be carefully incorporated into the model. All raised feature heights are defined using the most recent surveys available from the various sources, including LIDAR sources, USACE SWG surveys, and surveys from local jurisdictions. In this case, vertical positions were typically defined from the Texas 10-meter-by-10-meter LIDAR data set. However, the elevations were also confirmed or adjusted with 1-meter-by-1- meter LIDAR where available.
A series of hurricane scenarios were simulated using ADCIRC to determine the maximum water surface elevation near STP Units 3 and 4 resulting from storm surge. The PMH parameters selected for the ADCIRC runs were based on the storm scenario that that produced the maximum surge at the site during the prior analysis with SLOSH. Specifically, the PMH parameters selected for the ADCIRC runs based on NWS 23 are a radius to maximum winds of 24 miles (21 nm); an approach direction of 135° clockwise from the north (i.e. a northwesterly direction); a forward speed of 23 mph (20 knots); a central pressure of 26.19 in Hg; and a peripheral pressure of 30.12 in Hg. The only variables were the distance of the storm track from the site and the track direction.
The PMSS generated by ADCIRC, using NWS 48 wind profile, is estimated to be 29.3 ft above MSL. This PMSS will occur as the result of a hurricane traveling in a northwesterly direction (i.e., an approach direction of 135° clockwise from the north) passing within 24 miles of the STP site. During its life up to the point of landfall, the storm will have a constant forward speed of 23 mph, a central barometric pressure of 887 Mb, and a maximum sustained wind speed of 160 knots (184 mph). Upon landfall, the storm will continue in a northwesterly direction and began to decay gradually as it moves inland. The limiting storm and corresponding ADCIRC prediction are shown in Figures 2.4S.5-9 and 2.4S.5-10.
2.4S.5.2.4.3 Storm Surge Analysis Conclusions Subsection 2.4S.4 provides the flood elevation caused by a Main Cooling Reservoir (MCR) embankment breach. The flood level caused by the MCR breach is significantly higher than the probable maximum storm surge as calculated by SURGE, SLOSH, or ADCIRC. Therefore, the probable maximum storm surge caused by the PMH is not a design basis event for the maximum floodwater surface elevation at the safety-related STP 3 & 4 plant structures or for hydraulic forces acting against those structures.
2.4S.5.2.5 Storm Surge from Regulatory Guide 1.59 The PMH PMSS at Freeport, Texas, predicted by Regulatory Guide 1.59 (i.e., Reference 2.4S.5-4) is 23.48 ft MLW (22.8 MSL) (p. 1.59-48). The individual components contributing to the storm surge were 15.99 ft due to wind setup, 2.89 feet due to pressure setup, 2.4 ft due to initial rise, and 2.2 ft MLW (1.52 ft MSL) due to the 10% exceedance of the astronomical high tide. Assuming a historical mean sea level
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trend at Freeport, Texas, of 1.93 ft per century (Reference 2.4S.5-13) will continue, the adjusted storm surge elevation for Reference 2.4S.5-4 is 24.7 ft MSL.
However, the windfield calculations in Regulatory Guide 1.59 are based on an interim and unpublished 1959 report that has been superseded by NWS 23 (i.e., Reference 2.4S.5-1). Therefore, the determination of the storm surge from the bathystrophic model in Reference 2.4S.5-8, which is based on these earlier windfield calculations, is not considered valid and the PMSS estimate from Reference 2.4S.5-4 is not considered further.
2.4S.5.2.6 Seiches Seiches are standing waves of relatively long period which occur in lakes, canals, bays, and on the open coast. Other than the Gulf of Mexico and Matagorda Bay, there are no large bodies of water in the immediate vicinity of the site, and seiche has not been considered as the controlling influence for these bodies of water. Other than for floods on the Colorado River, the hurricane storm surge is the dominant factor responsible for coastal area flooding. Therefore, the flooding at the site due to seiche effects from seismic or atmospheric external forcing mechanisms is considered insignificant in comparison to the water level at STP 3 & 4 resulting from the failure of the MCR. Failure of the MCR is discussed in Section 2.4S.4. Seiche effects in the MCR due to atmospheric mechanisms are discussed in Subsection 2.4S.8.2.4.
2.4S.5.3 Wave Action and Breaking Wave Setup (Sw) Evaluation of the wave runup component as illustrated in Figure 2.4S.5-1 was performed as part of the dam break analysis discussed in Subsection 2.4S.4. Wave runup is more critical when it is combined with the dam failure flood level because the water surface elevation of 31.1 feet MSL resulting from the PMH is lower than the flood level (before wave runup) of 32.5 feet MSL predicted for the postulated upstream dam failure scenario. Breaking wave setup was in generally small and would have no impact to the conclusion of the flood risk assessment considering the conservatism in the analysis.
2.4S.5.4 Resonance Resonance effects are not considered as there are no resonance effects in the site area.
2.4S.5.5 Protective Structures The controlling event for the design basis flood is the MCR embankment breach discussed in Subsection 2.4S.4 and flood protection for the safety related facilities are discussed in Subsection 2.4.10. Real-time monitoring of hurricanes through the National Hurricane Center (NHC) are considered adequate warning of impeding hurricanes to allow for the implementation of the plant safety procedures discussed in Subsection 2.4S.14.
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2.4S.5.6 References 2.4S.5-1 “Meteorological Criteria for Standard Project Hurricane and Probable Maximum Hurricane Windfields, Gulf and East Coast of the United States,” National and Atmospheric Administration (NOAA) Technical Report NWS 23, Schwerdt, R. W., NOAA, 1979.
2.4S.5-2 “SLOSH: Sea, Lake, and Overland Surges from Hurricanes,” National and Atmospheric Administration (NOAA) Technical Report NWS 48, Jelesnianski, C. P., Chen, J. and W. A. Shaffer, NOAA 1992.
2.4S.5-3 “Storm Surge on the Open Coast: Fundamentals and Simplified Prediction,” Technical Memorandum No. 35, Bodine, B.R., U.S. Army Corps of Engineers Coastal Engineering Research Center, 1971.
2.4S.5-4 “Design Basis Floods for Nuclear Power Plants,” Regulatory Guide 1.59, Revision 2, U.S. Nuclear Regulatory Commission, 1977.
2.4S.5-5 “American National Standard for Determining Design Basis Flooding at Nuclear Reactor Sites,” ANSI/ANS 2.8, 1992.
2.4S.5-6 “Storm tracks for Atlantic Basin,” National Oceanic and Atmospheric Administration. Available at http://maps.csc.noaa.gov/hurricanes/download.html, accessed May 4 2007.
2.4S.5-7 “Hurricane Surge Frequency Estimated for the Gulf Coast of Texas,” Technical Memorandum No. 26, Bodine, B. R., U.S. Army Corps of Engineers, Coastal Engineering Research Center, 1969.
2.4S.5-8 “Verification Study of a Bathystrophic Storm Surge Model,” Technical Memorandum No. 50, Pararas-Carayannis, George, U.S. Army, Corps of Engineers – Coastal Engineering Research Center, May 1975.
2.4S.5-9 “HEC-RAS Version 3.1.1,” User’s Manual, Hydrologic Engineering Center, U.S. Army Corps of Engineers, 2003.
2.4S.5-10 “Flood Damage Evaluation Project, Volume II-B, Chapter 4, Hydrology and Volume II-C, Chapter 6, Hydraulics,” prepared for the Lower Colorado River Authority and Fort Worth District Corps of Engineers, Halff Associates, Inc, July 2002.
2.4S.5-11 “BR-7pT1.tif,” Scale 1:1,000,000, National Oceanic and Atmospheric Administration, 1986. Available at http://www.ngdc.noaa.gov/mgg/bathymetry/ maps/finals/BR-7/, accessed June 26, 2007.
2.4S.5-12 “Surface Stresses Produced by Rainfall,” Journal of Geophysical Oceanography (1): 145-148, Caldwell, D. R. and W. P. Elliott, 1971.
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2.4S.5-13 “Tides and Currents,” National Oceanic and Atmospheric Administration. Available at http://tidesandcurrents.noaa.gov/data_menu.shtml? stn=8772440%20Freeport,%20TX&type=Tide%20Data, accessed May 16, 2007.
2.4S.5-14 “An evaluation of the SLOSH Storm-Surge Model,” Bulletin of the American Meteorological Society 66(11): 1408-1411, Jarvinen, B. R. and Lawrence, M. B. 1985.
2.4S.5-15 “Design and Implementation of a Real-Time Storm Surge and Flood Forecasting Capability for the State of North Carolina,” Mattocks et al, Carolina Environmental Program, University of North Carolina, November 30, 2006
2.4S.5-16 “A Basin- to Channel-Scale Unstructured Grid Hurricane Storm Surge Model Applied to Southern Louisiana,” Westerlink et al, American Meteorological Society, March 2008.
2.4S.5-17 “A High-Resolution Coupled Riverine Flow, Tide, Wind, Wind Wave, and Storm Surge Model for Southern Louisiana and Mississippi. Part I: Model Development and Validation,” Bunya et al, American Meteorological Society, February 2010.
2.4S.5-18 “A High-Resolution Coupled Riverine Flow, Tide, Wind, Wind Wave, and Storm Surge Model for Southern Louisiana and Mississippi. Part II: Synoptic Description and Analysis of Hurricanes Katrina and Rita,” Dietrich et al, American Meteorological Society, February 2010.
2.4S.5-19 “Modeling Hurricane Waves and Storm Surge using Integrally-Coupled, Scalable Computations,” J.C. Dietrich et al., Coastal Engineering, July 9, 2010.
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Table 2.4S.5-1 Major Historic Hurricanes Impacting the Texas Coast 1900 to 2005 Date of Landfall Name 24 Sep 2005 Hurricane Rita 24 Sep 2004 Hurricane Ivan 15 Jul 2003 Hurricane Claudette 23 Aug 1999 Hurricane Bret 1 Aug 1989 Hurricane Chantal 16 Oct 1989 Hurricane Jerry 18 Sep 1988 Hurricane Gilbert 26 Jun 1986 Hurricane Bonnie 18 Aug 1983 Hurricane Alicia 10 Aug 1980 Hurricane Allen 8 Sep 1974 Hurricane Carmen 10 Sep 1971 Hurricane Fern 3 Aug 1970 Hurricane Celia 20 Sep 1967 Hurricane Beulah 17 Sep 1963 Hurricane Cindy 11 Sep 1961 Hurricane Carla 25 Jun 1959 Hurricane Debra 4 Oct 1949 1949 Hurricane 27 Aug 1945 1945 Hurricane 27 Jul 1943 1943 Hurricane 30 Aug 1942 1942 Hurricane 23 Sep 1941 1941 Hurricane 7 Aug 1940 1940 Hurricane 5 Sep 1933 1933 Hurricane 4 Aug 1933 1933 Hurricane 13 Aug 1932 1932 Hurricane 23 Jun 1929 1929 Hurricane 21 Jun 1921 1921 Hurricane 14 Sep 1919 1919 Hurricane 18 Aug 1916 1916 Hurricane 16 Aug 1915 1915 Hurricane 21 Jul 1909 1909 Hurricane 8 Sep 1900 Galveston Hurricane Source: References 2.4S.5-6 and 2.4S.5-7
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Table 2.4S.5-2 Probable Maximum Hurricane Characteristics
Peripheral Pressure (pw) 30.12 in. Hg.
Central Pressure (po) 26.19 in. Hg. Radius of Maximum Winds (R) 5 to 21 nautical miles Forward Speed (T) 6 to 20 knots
Table 2.4S.5-3 Probable Maximum Hurricane Scenarios and Probable Maximum Surge Elevations 10% Exc. Wind Pressure High Tide Total Surge Scenario (R, T) Vxs Setup Setup Initial Rise [1] Elevation (units) (mph) (feet) (feet) (feet) (feet MLW) (feet MLW) 1 (21 n. mi., 6 knots) 152.2 10.45 2.48 2.4 2.2 17.53 2 (21 n. mi., 20 knots) 158.2 11.74 2.44 2.4 2.2 18.79 3 (5 n. mi., 6 knots) 153.5 6.58 1.85 2.4 2.2 13.03 4 (5 n. mi., 20 knots) 159.6 6.89 1.75 2.4 2.2 13.24 Notes: The parameters given in the table are: R radius of maximum winds T translation speed VXSmaximum stationary wind speed
[1] 10% Exceedance of the High Tide (Reference 2.4S.5-5, p.19)
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Figure 2.4S.5-1 Components of the PMSS Coinciding With the PMH
Source: Reference 2.4S.5-3, p.20
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Figure 2.4S.5-2 Location of the Main Cooling Reservoir (MCR) and STP 3 & 4 Relative to the Lower Colorado River Mouth
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Figure 2.4S.5-3 Historic Hurricane Tracks of Major (i.e., Category 1 and Larger) Unnamned Hurricanes Impacting the Texas Coast Between 1852 and 1950
Source: Reference 2.4.S.5-6
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Figure 2.4S.5-4 Historic Hurricane Tracks of Major (i.e., Category 1 and Larger) Unnamned Hurricanes Impacting the Texas Coast from 1950 to 2006
Source: Reference 2.4S.5-6
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Figure 2.4S.5-5 Schematic of Matagorda, Freeport and Galveston Traverses
Source:Modified from Reference 2.4S.5-8, p. 78 to include Matagorda Traverse. The bottom profile along the traverse was obtained from the National Oceanic and Atmospheric Administration coastal bathymetry map (Reference 2.4S.5-11). The general location of STP 3 & 4 is noted with a red dot.
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Figure 2.4S.5-6 Longitudinal Profile of Water Surface (WS) Elevation
Source:Predicted by modified Halff-HEC-RAS model assuming unaltered cross-sectional geometry of Reference 2.4S.5-10, a 100-year flood in the Lower Colorado River, and PMSS conditions.
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Figure 2.4S.5-7 The Maximum of Maximum (MOM) Storm Surge for a Category 5 Hurricane at STP 3 & 4
Source:Predicted by SLOSH for STP 3 & 4 to occur for a storm with a 15 mph forward speed and northwest winds. STP 3 & 4 is identified with a blue flag. The cell used for the STP 3 & 4 PMH PMSS extrapolation is noted by a black dot. (Modified from Reference 2.4S.5-2).
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Figure 2.4S.5-8 USGS Quadrangle showing Little Robbins Slough and Colorado River relative to the STP 3 & 4 Main Cooling Reservoir (MCR)
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Figure 2.4S.5-9 PMH used in conjunction with ADCIRC model
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Figure 2.4S.5-10 PMSS Prediction based on the ADCIRC model
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2.4S.6 Probable Maximum Tsunami Hazards This subsection examines the Probable Maximum Tsunami (PMT) at the STP 3 & 4 site.
Evaluation of the PMT, as defined by Reference 2.4S.6-1, requires the use of best available scientific information to arrive at a set of scenarios reasonably expected to affect a nuclear power plant site. Reference 2.4S.6-1 recommends a hierarchical hazard assessment for screening exposure to hazards from natural phenomena. The hierarchical screening process is based on a series of stepwise, progressively more refined analyses that evaluate hazards resulting from a tsunami. The hierarchical hazard assessment includes regional screening, site screening, and, if necessary, a detailed PMT hazard assessment.
For this subsection, a tsunami may be characterized as a solitary positive wave, a negative wave coupled with a positive wave (i.e., an N-wave), a series of waves, or any combination of wave types with parameters defined by Table 2.4S.6-1 and Table 2.4S.6-2.
The STP 3 & 4 site is located about 15 mi (24 km) from the South Texas coast (Figure 2.4S.6-1). The site is about 3.2 mi west of the Lower Colorado River, and about 17 river miles, as measured in plan view along the Lower Colorado River, from the South Texas coast. The site grade elevations in the STP 3 & 4 power block area range from 32 ft MSL to 36.6 ft MSL, and all safety-related facilities in the power block are designed to be water tight at or below elevation 40.0 ft MSL as discussed in Subsection 2.4S.10. In addition, the Ultimate Heat Sink (UHS) and Pump House are designed to be watertight below 50 ft MSL (Subsection 2.4S.2.2). Flooding from tsunami events is not expected to affect the safety functions of the plant as discussed below.
2.4S.6.1 Probable Maximum Tsunami Tsunamis are gravity waves generated by large underwater disturbances. Reference 2.4S.6-1, Reference 2.4S.6-2, and Reference 2.4S.6-3 identify several types of tsunamigenic source mechanisms, including seismic events, volcanic events, submarine mass failures (SMFs), subaerial landslides, and impact of projectiles. With respect to a tsunami hazard assessment for the STP 3 & 4 project site, three primary forcing mechanisms are included in the analysis: seismic events, volcanic events, and SMFs (Reference 2.4S.6-1).
The tsunami hazard on the Gulf coast is summarized in Reference 2.4S.6-3. With respect to seismic events, Reference 2.4S.6-3 states that “tsunamis generated by earthquakes do not appear to impact the Gulf of Mexico coast.” Further, simulations of postulated “worst-case” far-field (i.e., tsunami sources originating from over 1000 km away) seismic events with potential to affect the US Gulf coast indicate a maximum wave height of about 0.15 m at the South Texas coast (Reference 2.4S.6-4). With respect to volcanic events, the largest conjectured event with potential to affect the US Atlantic and Gulf coasts has been postulated to be a tsunami from the eruption and collapse of the Cumbre Vieja volcano on the island of La Palma in the Canary Islands
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(Reference 2.4S.6-5). However, Reference 2.4S.6-3 indicates that this event is unlikely to affect the Gulf coast.
With respect to SMFs, Reference 2.4S.6-3 identifies several large SMF scars in carbonate, salt, and canyon to deep-sea provinces in the Gulf of Mexico. Many scars in these provinces correspond with relic events throughout the Quaternary (i.e., from 2.6 million to about 7500 years before the present, or yr BP). Multiple events have been identified for each scar. Notably, the geomorphology of SMFs in the Gulf of Mexico has been shown to be coupled with changes in sea level (Reference 2.4S.6-6 and Reference 2.4S.6-7). Reference 2.4S.6-6 documents sea-level changes over the last 140,000 years, with the last lowstand of 120 m below present sea level occurring less than 20,000 years ago.
With respect to near-field tsunami hazards at STP 3 & 4 (i.e., tsunamigenic sources within 124 mi or 200 km), the most prominent SMF scar is the East Breaks slump. The East Breaks slump is located approximately 88.2 mi (142 km) to the southeast of STP 3 & 4. Characterization and analysis of the East Breaks slump are discussed in detail in Subsection 2.4S.6.4.
Based on the hierarchical hazard assessment, the PMT for the STP 3 & 4 site is conjectured to occur from an SMF similar to the East Breaks slump. However, as the interpretation of a single wave height from a slump scar may not be sufficient to bound the PMT flood risks on STP 3 & 4 due to the uncertainties inherent in the assessment, a range of potential conditions were simulated at the East Breaks slump location. Simulations were performed using a hydrodynamic code known as the Method of Splitting Tsunami (MOST) (References 2.4S.6- 8 and 2.4S.6-9). These simulations were intended to bracket any near-field tsunami hazard from a SMF in the Gulf of Mexico.
Initial conditions of a negative wave (i.e., a wave caused by the drawdown of the water surface due to a sliding mass) were based on curve fits of sliding block experiments of Reference 2.4S.6-10 and Reference 2.4S.6-11. These initial conditions were subsequently scaled into a three-dimensional dipole wave (i.e., a negative wave and positive wave with unequal intensities) based on relationships presented in References 2.4S.6-12, 2.4S.6-13, and 2.4S.6-14.
The SMF scenarios postulated include initial wave deformation areas (i.e., areas differing from MSL) ranging from 410 km2 to 9932 km2 (158 mi2 to 3835 mi2, respectively). Four scenarios were modeled as candidate PMT events. The simulation results indicate that all candidate PMT events were rapidly diffused by the continental shelf offshore of the South Texas coast, with nearly all remaining wave energy being reflected by the barrier islands. For negative wave elevations ranging from -7 m (23.0 ft) to -140 m (459.3 ft) and positive wave elevations ranging from 3 m (9.84 ft) to 60 m (197 ft), maximum predicted runup from the simulations did not exceed 2 m (6.6 ft) above MSL. Maximum flow depth from these simulations did not exceed 3.25 m (10.7 ft).
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The evaluation of the maximum flood level for a PMT event also included an analysis of the 10% exceedance of the astronomical high tide and long-term sea level rise. As regulatory criteria for these components are only available for the Probable Maximum Storm Surge (PMSS), the criteria for the PMSS in Regulatory Guide 1.59 (1977) (Reference 2.4S.6-15) were adopted for the PMT analysis. Based on tide gage data for NOS Station #8772440, which is located in Freeport, Texas, the 10% exceedance of the astronomical high tide was estimated to be 3.54 ft (1.08 m) MSL (Reference 2.4S.6-16). The long-term sea level rise for this station was estimated by NOAA to be 0.171 in (4.35 mm) per year or 1.43 ft (0.44 m) per century (Reference 2.4S.6-17). The peak flood level due to a PMT event is therefore estimated to be of the order of 11.5 ft (3.52 m) MSL within the next century (i.e., 6.56 ft tsunami runup + 3.54 ft 10% exceedance of the astronomical high tide + 1.43 ft sea-level rise = 11.5 ft MSL).
A tsunami runup of 11.5 ft MSL is below the design basis flood level of 40.0 ft MSL that is postulated from a Main Cooling Reservoir (MCR) breach event (Subsection 2.4S.4). PMT is therefore not the controlling event for the design basis flood determination for STP 3 & 4 safety-related structures.
2.4S.6.2 Historical Tsunami Record Information and data on tsunami-generating earthquakes and runup events are included in the National Geophysical Data Center (NGDC) hazards database (Reference 2.4S.6-18). The NGDC database contains information on source events and runup elevations for worldwide tsunamis from about 2000 BC to the present (Reference 2.4S.6-1). Each event in the NGDC database has a validity rating ranging from 0 to 4, with 0 for erroneous events, 1 for very doubtful events, 2 for questionable events, 3 for probable events, and 4 for definite events. Similarly, each event includes a cause code identifying the forcing mechanism (e.g., earthquake, volcano, landslide, or any combination thereof).
With respect to published literature, the publication titled “Caribbean Tsunamis: A 500- Year History from 1498-1998,” is a compendium of data and anecdotal material on tsunamis reported in the Caribbean from 1498 to 1997 (Reference 2.4S.6-19). Reference 2.4S.6-20 includes source events and runup elevations for the Caribbean Sea and Eastern United States from 1668 to 1998, respectively. The USGS has published a fact sheet showing locations of plate boundaries in the Caribbean and tsunami-generating earthquakes from 1530 to 1991 (Reference 2.4S.6-21). The map is shown in Figure 2.4S.6-2. Additionally, NOAA’s Center for Tsunami Research, in conjunction with the Pacific Marine Environmental Laboratory, publishes information and analyses on tsunami sources and tsunami events (Reference 2.4S.6-22).
Three historical tsunami runup events have been documented for the State of Texas, USA, in the NGDC database and in published literature. The first documented tsunami event for the Texas coast occurred on October 24, 1918. This tsunami was reported to be an aftershock of the Mw=7.5 October 11, 1918, earthquake near Puerto Rico (Reference 2.4S.6-23, p. 73). The epicenter of the earthquake was reported at 18.5º N and 67.5º W (Reference 2.4S.6-19, p. 201), which is approximately nine miles northwest of Puerto Rico and located in the Mona Rift. As described in Reference 2.4S.6-19 (p. 201), this earthquake was “considered a terrific aftershock of the October
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11 event...[with] a small wave [being] recorded at the Galveston, Texas, tide gage.” This event has a validity rating of four. The magnitude of tsunami runup was not reported.
The second documented tsunami event for the Texas coast occurred on May 2, 1922. The epicenter of the earthquake associated with this event was reported at 18.4º N and 64.9º W (Reference 2.4S.6-19, p. 201). Reference 2.4S.6-19 (p. 201) stated that “a wave with an amplitude of 64 cm was reported on a tide gage at Galveston. A train of three waves with a 45-minute period was followed in 8 hours by a 28-cm wave in a similar train of smaller waves. Parker [Reference 2.4S.6-24] associated it with an earthquake felt 4 hours earlier at Vieques, Puerto Rico.” However, according to Campbell [Reference 2.4S.6-25, p. 56], the shock had a duration of only two seconds. Therefore, the earthquake is unlikely to have been the tsunamigenic source. The validity rating of this event in the NGDC database is a two (i.e., a questionable event). No runups were documented along the Gulf coast for the primary shock of the 1922 earthquake. The surge was presumed to have been locally amplified by the inland position of the tidal gage (Reference 2.4S.6-24, p. 30). The magnitude of the 1922 earthquake or the aftershock has not been estimated.
The third documented tsunami event for the Texas coast occurred on March 27, 1964. The event was recorded on a tide gage in Freeport, Texas (Reference 2.4S.6-26). While the validity of this event was a four, estimates of the wave height vary considerably between eyewitness accounts and tide gage data. Reference 2.4S.6-26 (p. 261) notes that “in several reports from eyewitnesses in the coastal regions of Louisiana and Texas, waves up to 6 feet (2 meters) in height were observed.” However, Reference 2.4S.6-26 (p. 261) reports that the “maximum height of the recorded seiche at 0400 GMT is about seven inches (18 cm),” and that the “true wave height may have been several feet ([i.e.,] about a meter).” This event coincided with the 1964 Alaska (Mw=9.2) earthquake located between the Aleutian Trench and the Aleutian Volcanic Arc (Reference 2.4S.6-27). Additional analyses of tide gage records from the 1964 event report the maximum measured height of the low-frequency waves along the Texas coast from the Alaska earthquake ranged from 0.22 to 0.84 feet (Reference 2.4S.6-28, p. 26).
2.4S.6.3 Source Generator Characteristics Tsunamigenic source characteristics with potential to affect the US Atlantic and Gulf coasts are summarized in Reference 2.4S.6-3, several databases, and published literature as discussed in the following subsections.
2.4S.6.3.1 Seismic tsunamis In comparison to tsunami runup events that have been documented in the Caribbean (Reference 2.4S.6-29), the Texas coast has had relatively few runup events. For example, as noted previously, Reference 2.4S.6-3 (p. ii) stated that “tsunamis generated by earthquakes do not appear to impact the Gulf of Mexico coast.” However, tsunamigenic earthquake sources that may affect the Gulf of Mexico are discussed in Reference 2.4S.6-3 (pp. 105-112). As stated in Reference 2.4S.6-3 (p. 105):
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“Earthquake-generated tsunamis generally originate by the sudden vertical movement of a large area of the seafloor during an earthquake. Such movement is generated by reverse faulting, most often in subduction zones. The Gulf of Mexico basin is devoid of subduction zones or potential sources of large reverse faults. However, the Caribbean basin contains two convergence zones whose rupture may affect the Gulf of Mexico, the North Panama Deformation Belt and the Northern South America Convergent Zone.”
As stated in Reference 2.4S.6-3, source areas with potential for tsunamigenesis affecting the US Gulf Coast include the North Panama Deformation Belt and the Northern South American Convergent Zone (Table 2.4S.6-3). With respect to the North Panama Deformation Belt, Reference 2.4S.6-3 stated that:
“the largest segment of the North Panama Deformation Belt is oriented between 60°-77°. The 1882 Panama earthquake appears to have ruptured at least 3/4 of the available length of the convergence zone, and was estimated to have a magnitude of 8. While there was significant tsunami damage locally, there were no reports from the Gulf of Mexico of a tsunami from this earthquake. The low convergent rate (7-11 mm/yr) across the North Panama Deformation Belt supports long recurrence interval for large earthquakes.”
The Harvard Centroid-Moment-Tensor (CMT) catalog was searched for potential seismogenic earthquakes in the two source regions of Table 2.4S.6-3 (Reference 2.4S.6-30). The following criteria were used for searching the CMT catalog within the North Panama Deformation Belt: a date range of 01/01/1976 (i.e., the start of the database) through 11/04/2008; latitude from 9° N to 12° N; longitude from 83° W to 77° W; depth from 0 to 1000 km; and moment magnitude (Mw) range from 6.5 to 10. The selection of a lower bound of Mw=6.5 is based on criteria from Reference 2.4S.6-2 (p. 23) for a threshold moment magnitude of tsunamigenesis from earthquakes. One record was identified in the CMT catalog with these criteria. On 04/22/1991, a Mw=7.6 earthquake occurred at depth of 15 km and at a latitude of 10.10° N and a longitude of 82.77° W, located about 20 mi. (32 km) offshore of the town of Limon, Costa Rica. Source parameters for the earthquake were documented as a strike of 103 degrees, a dip of 25 degrees, and a rake of 58 degrees. Source parameters for earthquakes in the North Panama Deformation Belt with moment magnitudes below 6.5 are discussed in Reference 2.4S.6-3. With respect to the far-field tsunami hazard on the South Texas coast, these additional sources are not reasonably expected to exceed the tsunamigenic potential of scenarios simulated by Reference 2.4S.6-3 and Reference 2.4S.6-4.
The following criteria were used for searching the CMT catalog within the Northern South American Convergent Zone: a date range of 1/1/1976 to 11/04/2008; latitude from 11.5° N to 14° N; longitude from 77° W to 64° W; depth from 0 to 1000 km; and moment magnitude range from 6.5 to 10. No records were identified in the CMT catalog with these criteria. By broadening the criteria to include earthquakes from 0 Probable Maximum Tsunami Hazards 2.4S.6-5 Rev. 12 STP 3 & 4 Final Safety Analysis Report Therefore, the assessment of far-field tsunami hazards in this region was based on tsunami simulations in References 2.4S.6-4 and 2.4S.6-3. Reference 2.4S.6-4 performed tsunami simulations of seismic-borne tsunamis from postulated “worst- case” events using a two-dimensional depth-integrated hydrodynamic model described in Reference 2.4S.6-31. The following cases were used in the assessment (Reference 2.4S.6-4, p. 305): 1. Mw=9.0 at 66° W and 18° N (Puerto Rico trench); 2. Mw=8.2 at 85° W and 21° N (Caribbean Sea); 3. Mw=9.0 at 66° W and 12° N; and 4. Mw=8.2 at 95° W and 20° N (near Veracruz, Mexico). The source location of Case 3 at 66° W and 12° N is cited in Reference 2.4S.6-4 (p. 305) as the North Panama Deformation Belt, but the location corresponding to 66° W and 12° N is the South Caribbean Deformed Belt (Reference 2.4S.6-3, p. 110). Source parameters for the model cases in Reference 2.4S.6-4 were based on the formulae of Reference 2.4S.6-32. For example, source parameters for the Veracruz scenario (Reference 2.4S.6-4, p. 305) are provided in Table 2.4S.6-4. Reference 2.4S.6-4 (p. 305) stated that the model sources were aligned with local strike. Reference 2.4S.6-4 (p. 311) concluded that “sources outside the Gulf are not expected to create a tsunami threatening to the Gulf coast.” Reference 2.4S.6-4 attributed this result primarily due to friction losses as the waves travel through the Straits of Florida and throughout islands in the Caribbean. Tsunami simulations in Reference 2.4S.6-3 complemented earlier work by Reference 2.4S.6-4, with Reference 2.4S.6-3 (p. 117) stating that: “in general, these results are consistent with the findings of Knight (2006) [Reference 2.4S.6-4], where the far-field tsunamis generated from earthquakes located beneath the Caribbean Sea are higher along the Gulf coast than the Atlantic coast because of dissipation through the Greater Antilles islands. Conversely, tsunamis generated from earthquakes north of the Greater Antilles are higher along the Atlantic coast than the Gulf coast.” Reference 2.4S.6-4 (p. 311) stated that one reason for this conclusion was that “the Atlantic and Gulf coasts are nearly independent since the hydrodynamic connection between basins is through the narrow Straits of Florida and through the Caribbean, where bottom friction losses appear to be large.” Additionally, the largest deepwater wave from the Reference 2.4S.6-3 simulations was produced from the north Venezuela subduction zone. The maximum wave height from the north Venezuela subduction zone from a buoy at a depth of 250-m offshore of New Orleans, Louisiana, was estimated to be 6 cm (Reference 2.4S.6-3, p. 130, Figure 7- 4e, “Station 1”). 2.4S.6-6 Probable Maximum Tsunami Hazards Rev. 12 STP 3 & 4 Final Safety Analysis Report While tsunamigenic earthquakes within the Gulf of Mexico have not been recorded, Reference 2.4S.6-4 included a tsunami simulation assuming a magnitude Mw=8.2 earthquake offshore of Veracruz, Mexico. The resulting wave amplitude at the South Texas coast was about 0.35 m. Intraplate earthquakes are less common than earthquakes occurring on faults near plate boundaries, but several earthquakes in the past three decades had epicenters within the Mississippi Canyon and Fan province (Reference 2.4S.6-3). In recent time, the most severe earthquake in this region occurred on September 10, 2006. The moment magnitude was recorded as 5.8. The second largest earthquake in this region occurred on February 10, 2006 with a moment magnitude of 5.2. The United States Geological Survey (USGS) concluded that earthquakes of this magnitude are unlikely to produce any destructive tsunami (Reference 2.4S.6-33). 2.4S.6.3.2 Seismic seiches The only documented event of a seismic seiche on the Texas coast is from the 1964 Alaska earthquake. Reference 2.4S.6-28 indicated that the horizontal acceleration associated with seismic surface waves from the Alaska shock appears to have varied markedly within North America. The amplitude of horizontal acceleration was especially large along the Gulf coast. Reference 2.4S.6-28 (p. 27) further stated that “thick deposits of sediments of low rigidity along the Gulf coast, for example, are capable of amplifying the horizontal acceleration of surface waves to a considerable extent; this accounts for the concentration of seiches that occurred along the Gulf coast.” While the Mw=9.5 magnitude 1960 earthquake in Chile might also have been expected to have caused seiches along the Texas coast, tide gages along the Gulf coast did not record any event. The Mw=7.8 New Madrid earthquake that occurred on February 7, 1812 (Reference 2.4S.6-34), which is the largest earthquake recorded in the contiguous United States, produced significant seiches in the Mississippi River and in waterways along the Texas state boundary (Reference 2.4S.6-20, p. 124). However, no records exist to indicate that the 1812 New Madrid earthquake directly affected the South Texas coast or the Lower Colorado River near STP 3 & 4. 2.4S.6.3.3 Volcanism-based tsunamis Reference 2.4S.6-3 did not cite a tsunami hazard to the Gulf coast from volcanism. For example, Reference 2.4S.6-3 stated that “far-field landslides, such as in the Canary Islands, are not expected to cause a devastating tsunami along the U.S. Atlantic coast.” Previous studies have conjectured that the eruption and collapse of the Cumbre Vieja volcano on the island of La Palma in the Canary Islands could potentially affect the coast of Florida, USA, with a 25-m wave (Reference 2.4S.6-5). A recent assessment of Reference 2.4S.6-5 was discussed in Reference 2.4S.6-3 (p. 57): “as envisioned by Ward and Day (2001) [Reference 2.4S.6-5], a flank collapse of the volcano may drop a rock volume of up to 500 km3 into the surrounding ocean. The ensuing submarine slide, which was assumed to propagate at a speed of 100 m/s, will generate a strong tsunami with amplitudes of 25 m in Florida. In addition, [Ward and Day, 2001] claimed that the collapse of Cumbre Probable Maximum Tsunami Hazards 2.4S.6-7 Rev. 12 STP 3 & 4 Final Safety Analysis Report Vieja is imminent. In our opinion, the danger to the U.S. Atlantic coast from the possible collapse of Cumbre Vieja is exaggerated. Mader (2001) [Reference 2.4S.6-35] pointed out that Ward and Day’s (2001) assumption of linear propagation of shallow water waves is incorrect, because it only describes the geometrical spreading of the wave and neglects dispersion effects. A more rigorous hydrodynamic modeling by Gisler et al. (2006) [Reference 2.4S.6-36], confirms Mader’s criticism. Their simulations show significant wave dispersion and predict amplitude decay proportional to r-1 for a 3-dimensional model and r-1.85 for a 2- D model (r is distance). [Reference 2.4S.6-36] predicted [a] wave amplitude for Florida is between 1 [and] 77 cm. [Reference 2.4S.6-36 used] slightly smaller volume, 375 km3, than Ward and Day (2001), but a much higher slide speed, that is much closer to the phase speed for tsunamis in the deep ocean (4,000 m of water).” Further research on the La Palma event indicated that the distribution of slide blocks on the ocean bottom suggests that the collapse of Cumbre Vieja may not have been the result of a single catastrophic event, but the result of several smaller events. A recent report on potential tsunami threats to the United Kingdom concluded that “studies of the offshore turbidities [i.e., poorly sorted sediment that is deposited from a density flow of mixed water and sediment] created by landslides from the flanks of the Canary Islands suggest that these result from multiple landslides spread over periods of several days” and are therefore “likely to create tsunamis of only local concern” (Reference 2.4S.6-37, p. 23 and p. 30, respectively). As no tsunamis have been documented in the Gulf of Mexico as a result of recent volcanic eruptions or associated mass wasting events (i.e., gravity-driven mass movement of soil, regolith, or rock moving downslope), this mechanism is not considered further as a potential source of tsunamis along the South Texas Coast. 2.4S.6.3.4 Submarine slump tsunamis Reference 2.4S.6-3 (p. 35) cites four credible SMF source areas in the Gulf of Mexico: the Florida Escarpment, Campeche Escarpment, Northwest Gulf of Mexico, and the Mississippi Canyon (Figure 2.4S.6-3). These four SMF source areas are located in three geologic provinces: a carbonate province, a salt province, and a canyon to deep- sea fan province. The postulated SMF sources in the carbonate province are located offshore of West Florida and in the Campeche Escarpments north of the Yucatan Peninsula (Reference 2.4S.6-3). The largest scar in this region is along the central part of the West Florida Slope and is estimated as 120 km long, 30 km wide, with a total volume of material removed of about 1,000 km3. However, formation of the scar was believed to have occurred as a result of multiple events. Most of the sediment was estimated to have been removed before the middle of the Miocene [c. 11.6 million years ago]. Reference 2.4S.6-3 (p. 28) stated the following: “During the Mesozoic, an extensive reef system developed around much of the margin of the Gulf of Mexico Basin by the vertical growth of reefs and carbonate shelf edge banks. This reef system is exposed along the Florida Escarpment 2.4S.6-8 Probable Maximum Tsunami Hazards Rev. 12 STP 3 & 4 Final Safety Analysis Report and the Campeche Escarpment that fringe the eastern and southern margins of this basin. These escarpments stand as much as 1,500 m above the abyssal plain floor, and have average gradients that commonly exceed 20° and locally are vertical. Reef growth ended during the Middle Cretaceous, and subsequently the platform edges have been sculpted and steepened by a variety of erosional processes.” The salt province is located in the northwestern Gulf of Mexico. Reference 2.4S.6-3 (p. 32) stated that Geologic Long-Range Inclined Asdic (GLORIA) imagery identified 37 SMFs in the salt province and along the base of the Sigsbee Escarpment. The largest of these landslides is the East Breaks slump, which is discussed in additional detail below. With respect to the morphology of the salt province, Reference 2.4S.6-3 (pp. 27-28) stated the following: “Salt deposited in the late Jurassic Gulf of Mexico basin, the Louann salt, originally underlay large parts of Louisiana, southern Texas, and the area offshore of Mexico in the Bay of Campeche. As sediment eroded from the North American continent was deposited on this salt sheet throughout the Mesozoic and Cenozoic, the increased load caused the salt to flow with it migrating southward from the source area into the northern Gulf of Mexico. Presently the Louann salt underlies large parts of the northern Gulf of Mexico continental shelf and continental slope. South of Louisiana and Texas, the Sigsbee Escarpment is a pronounced cliff that marks the seaward limit of the shallowest salt tongue. As the salt is loaded, it flows both seaward and also upward through the overlying sediment column as cylindrical salt domes. The morphology of the salt sheet varies considerably across the margin. Salt domes are most common under the continental shelf, and most of the original salt sheet between individual domes in this region has been removed in response to the sediment loading, and migrated farther seaward.” Other SMFs identified in the salt province have areas that are an order of magnitude lower than the East Breaks slump (Reference 2.4S.6-3), and are not further considered. Three canyon to deep-sea fan systems were formed during the Pliocene and Pleistocene: the Mississippi, Eastern Mississippi, and Bryant systems (Figure 2.4S.6- 3). The Mississippi system is the largest of the three systems, though Reference 2.4S.6-3 states that the resumption of hemipelagic sedimentation at the head of the Mississippi Canyon by 7500 yr BP indicates that the largest of the landslide complexes ceased being active by the middle of the Holocene. The largest SMF in the complex covers approximately 23,000 km2 and reaches 100 m in thickness, with a volume estimated to be about 1,750 km3. GLORIA sidescan sonar data suggests that this feature consists of at least two separate events (Reference 2.4S.6-3). The Eastern Mississippi and Bryan Canyon systems are smaller than the Mississippi Canyon system. The Eastern Mississippi system has a deposit that is “approximately 154 km long, as much as 22 km wide, and covers an area of 2,410 km2” (Reference Probable Maximum Tsunami Hazards 2.4S.6-9 Rev. 12 STP 3 & 4 Final Safety Analysis Report 2.4S.6-3, p. 34). With respect to the Bryant system, Reference 2.4S.6-3 (pp. 33-34) states that “The Bryant Canyon system was immediately downslope of a shelf edge delta system, and failure of this system has been proposed as the explanation for thick chaotic deposits in mini basins along the path of this canyon system Debris from the failure of the shelf edge delta was transported down the Bryant Canyon system, but these landslide deposits predate and are buried by the smaller landslides off the mini-basin walls.” 2.4S.6.4 Tsunami Analysis Tsunami modeling was conducted for a tsunami originating at the location of the East Breaks slump near the South Texas coast. For all scenarios, the tsunamigenic source was a SMF. As with Reference 2.4S.6-12 and Reference 2.4S.6-13, a series of scaled dipolar initial conditions were used for bracketing a conservative range of initial wave heights. Hydrodynamic simulations were modeled using a series of codes known as the Method of Splitting Tsunami (MOST) (References 2.4S.6-8). For all model simulations, maximum runup along the South Texas coast did not exceed 2 m (6.56 ft) above Mea Sea Level (MSL). The following paragraphs discuss the geologic setting of the East Break slump, followed by discussion of hydrodynamic simulations with MOST. The East Breaks slump is located approximately 88.2 mi (142 km) to the southeast of STP 3 & 4 (Figure 2.4S.6-4). The coordinates of the slump are approximately 27.57° N and 95.64° W. The slump is comprised of an eastern lobe and a western lobe. Reference 2.4S.6-38 (p. 2) stated that “the western and eastern lobes are thought to have formed by two different processes, and actually at two different, but relatively close, time periods. The western lobe formed as slump and debris deposits traveled downslope. The eastern lobe is more consistent with turbidity flow currents in the upper parts of the slide and leveed channels in the middle and lower portions of the slide.” Further, Reference 2.4S.6-38 (p. 3) stated that “the eastern lobe appears more channelized and consists of density flow-type fill with few large slump and intact blocks. The western lobe, therefore, carried the bulk of the failed material and the energy level of the failure was much greater.” As the eastern lobe was unlikely to have influenced tsunamigenesis, only the western lobe was used for the simulations. The age of the East Breaks slump is not precisely known. Reference 2.4S.6-39 (p. 366) stated that the most recent mass wasting event responsible for the formation of the western lobe occurred about 16,000 yr BP, and after the formation of the bulk of the eastern lobe. Reference 2.4S.6-7 stated that “the East Breaks Slide is a site of [sea level] lowstand instability, and seismic [reflection] data shows repeated slope failure in this area. During late Quaternary lowstands of sea level, large deltas built up along the Texas-Louisiana shelf margin, and the present continental shelf [became] exposed as a subaerial coastal plain.” Reference 2.4S.6-7 also stated that “it is clear that most sliding on the Texas-Louisiana slope occurred during the late Pleistocene [c. 10,000 - 29,000 years BP] lowstands of sea level when sedimentation rates on the upper slope were high.” 2.4S.6-10 Probable Maximum Tsunami Hazards Rev. 12 STP 3 & 4 Final Safety Analysis Report With respect to stability, Reference 2.4S.6-3 notes that information on the age of landslides in the salt province is limited. Most landslides appear to have been active during oxygen isotope stages 2, 3, and 4 (18,170-71,000 yr BP) when salt movement due to sediment loading was most active. The age of the most recent landslide is less well established. For example, Reference 2.4S.6-7 stated that that no major SMFs have occurred in the northwestern Gulf of Mexico in the Holocene (i.e., the last 10,000 years). Reference 2.4S.6-7 (p. 309) stated: "Studies of submarine slides invariable prompt the question: Is the slope now completely stabilized? It is clear that most sliding on the Texas-Louisiana slope occurred during the late Pleistocene lowstands of sea level when sedimentation rates on the upper slope were high. No major Holocene slides have been documented. Low rates of deposition may be a primary reason for the present stability over much of the upper slope, and a further indication that sediments are relatively stable." However, Reference 2.4S.6-3 suggests the occurrence of at least one landslide during the Holocene, with “one unpublished age date of a sample below a thin landslide deposit (<3 m thick) indicates that it is younger than 6,360 yr BP.” Therefore, no major SMFs have been documented for the salt province in over 6,300 years. With respect to dimensions of the East Breaks slump scar, estimates of width, length, area, and volume have varied with different studies. For example, Reference 2.4S.6-40 stated that the slump “consists of a 20-km wide head scarp initiated along the 150-meter isobath, a 55 km long erosional chute, ending in a 95x30 km accretionary lobe. Total extent of the feature is 160 km from the shelf edge to a depth of 1,500 m” and “slumped deposits extend over a 3,200-km2 area with a volume on the order of 50-60 km3.” Reference 2.4S.6-7 stated that “the East Breaks Slide is a prominent mass-transport feature. Revised bathymetry shows that the slide originated on the upper slope (200-1000 m), in front of a sandy late Wisconsinan shelf-margin delta, where the gradient is up to 3°. It was deposited in a middle slope position (1000- 1500 m) where the gradient is about 0.5°. Side-scan sonar data indicates that the slide is a strongly backscattering feature extending more than 110 km downslope from the shelf edge.” Reference 2.4S.6-3 (p. 32) stated that “the largest of these failures occurs in the northwestern Gulf of Mexico, is 114 km long, 53 km wide, covers about 2,250 km2, and has been interpreted to consist of at least two debris flows.” Source parameters for the East Breaks slump were estimated using three arc-second bathymetry data from the National Geophysical Data Center (NGDC) (Reference 2.4S.6-41). Source parameters, including slump width, length, and thickness, were estimated using a Geographic Information Systems (GIS) environment (Figure 2.4S.6-5). Slump width was estimated to be approximately 13.4 km. The length of the erosional chute was estimated to about 42 km. Based on a transect across the erosional chute, slump thickness was estimated to be about 100 m (i.e., see Path Profile A to A’ in Figure 2.4S.6-5). With respect to slope, Reference 2.4S.6-40 stated that “initial failure of the slump took place on very low angle slopes of less than two degrees while present slump deposits have an average seafloor slope of one-degree.” While a vertical drop of 850 m over a length of 42 km indicates a bed slope of Probable Maximum Tsunami Hazards 2.4S.6-11 Rev. 12 STP 3 & 4 Final Safety Analysis Report approximately 1.1 degrees, local bed slopes measured in GIS using a longitudinal transect along the erosional chute indicate a local maximum slope of about 1.95°. Therefore, a maximum local slope of 2° was used for a conservative estimate. Similarly, initial depth of the slide was estimated conservatively using the 200-m and 1000-m bathymetry contour elevations. Therefore, initial depth was estimated to be 600 m (i.e., (200 m + 1000 m)/2) (Figure 2.4S.6-5). Total length of the slide was taken from Reference 2.4S.6-3 as 114 km. With respect to simulations, tsunami modeling was performed with MOST. Validation of the MOST code is well established (Reference 2.4S.6-9). MOST is based on the following three phases of long wave evolution (Reference 2.4S.6-8): (i) A “Deformation Phase” that generates the initial conditions for a tsunami by simulating ocean floor and corresponding free surface changes due to a forcing mechanism; (ii) A “Propagation Phase” that propagates the generated tsunami across the deep ocean using Nonlinear Shallow Water (NSW) wave equations; and (iii) An “Inundation Phase” that simulates the shallow ocean behavior of a tsunami by extending the NSW calculations using a multi-grid runup algorithm to predict coastal flooding and inundation. Specification of an initial deformation condition was based on scaling a dipole wave (i.e., a wave with a dipolar structure). A dipole wave is similar to the structure of an N-wave (i.e., a tsunami with a leading negative or depression wave followed by a positive elevation wave). An initial dipole wave is characteristic of tsunamis from submarine landslides, and possibly all tsunamis (Reference 2.4S.6-14). After specifying an initial deformation condition, the propagation phase is based on a simplified form of the Navier-Stokes equations referred to as the nonlinear shallow water (NSW) equations (Reference 2.4S.6-8). The NSW equations are solved numerically with a finite difference algorithm and a series of nested grids (Reference 2.4S.6-42). Since tsunami wavelength becomes shorter during shoaling, a series of nested grids are required for maintaining resolution of the wave with decreasing water depth. Therefore, three grids (i.e., A, B and C) were used for the MOST simulations (Figure 2.4S.6-6). The grids were derived from NGDC topography and bathymetry data (Reference 2.4S.6-41). Grid spacing between nodes was equal to 12 arc-seconds, 6 arc-seconds, and 6 arc-seconds, respectively. MOST uses a moving boundary calculation for estimating tsunami runup onto dry land. Details of the moving boundary are discussed in Reference 2.4S.6-43. While friction factors are not used in the propagation phase of MOST, a friction factor must be specified for the inundation phase. Following sensitivity simulations, this value was set equal to 0.01 (i.e., n=0.1). Reference 2.4S.6-2 states that “several studies show that an unsteady flow during runup is not very sensitive to changes in the roughness coefficient”, and that “any moving boundary computation induces numerical friction 2.4S.6-12 Probable Maximum Tsunami Hazards Rev. 12 STP 3 & 4 Final Safety Analysis Report near the tip of the climbing wave (except in a Lagrangian formulation).” However, this value was selected based on a series of sensitivity tests, where the most conservative value that could be used without numerical instability over the full duration of the simulation was selected. Initial wave heights (i.e., initial elevation of the depression wave due to a slump) were estimated using the slump center of mass motion model described in Reference 2.4S.6-10 and Reference 2.4S.6-11. Source parameters documented in the paragraphs above and in Figure 2.4S.6-5 were used for estimating initial wave height. Specific gravity of the slump mass was assumed to be equal to 2. The 100-m thickness (T) with respect to the 600-m initial depth (h) (T/h=0.17) and the thickness relative to the 42 km length (b) of the erosional chute (T/b=0.002) suggests initial wave height from the East Breaks slump would be relatively small. Using the NGDC bathymetry data (Figure 2.4S.6-5), initial wave height for the East Breaks slump was estimated to be 7.9 m. Considering variability in interpreting landslide dimensions, the estimate of 7.9 m is similar to the “tsunami wave on the order of 7.6 meters” predicted by Reference 2.4S.6-40. As noted in the preceding paragraphs, estimates of slump dimensions can vary considerably with different interpretations. Therefore, estimates of initial conditions (i.e., wave height and shape) are not easily replicable between investigators. Consequently, after establishing a range of possible wave heights from scaling studies in Reference 2.4S.6-11 and Reference 2.4S.6-14, initial dipole conditions were developed for the East Breaks slump simulations by using SMF wave shapes developed for other SMF events. These events include the Palos Verdes (PV) landslide in Southern California (Reference 2.4S.6-12) and the 1998 Papua New Guinea (PNG) slump in the Sandaun Province (Reference 2.4S.6-13). Scaled initial conditions were used for the simulations as relatively little data exists for SMFs, and the PV and PNG events have been tested extensively by the tsunami community (Reference 2.4S.6-13 and Reference 2.4S.6-14). Four scenarios were modeled as candidate PMT events. Candidate PMT events included waves with high initial wave heights relative to wavelength (i.e., steep waves), and waves with high initial wave heights relative to width. Minimum (negative) and maximum (positive) elevations of the initial wave deformations are listed in Table 2.4S.6-5. Steep wave scenarios included PV and PV(x20); wide wave scenarios included PNG and a hypothetical “Monster “condition.” PV, which has a deformation area of 411 km2, was developed as a minimum estimate of initial wave height for the East Breaks slump (Table 2.4S.6-5). PV(x20), which is PV scaled in elevation by twenty times and with a slightly smaller deformation area of 387 km2, was developed as a maximum estimate of initial wave height for the East Breaks slump. PNG is scaled directly from the Papua New Guinea submarine slump described in Reference 2.4S.6-13, and has a deformation area of 879 km2, which is about twice as large as PV. A hypothetical “Monster” condition was also developed as a complementary case for the East Breaks slump. The hypothetical “Monster” condition has not been tested by the tsunami community. Rather, the hypothetical “Monster” case was developed as a complementary case for the East Breaks slump to test a very wide initial wave (i.e., Probable Maximum Tsunami Hazards 2.4S.6-13 Rev. 12 STP 3 & 4 Final Safety Analysis Report initial deformation area of 9932 km2 or 3835 mi2). All initial conditions were located at the centroid of the slump and oriented to relative to the slump direction. MOST output includes maximum runup estimates (i.e., maximum inland elevation inundated by the tsunami above MSL). Maximum runup ranges from 1 to 2 m (3.28 to 6.56 ft, respectively) MSL for the South Texas Coast near STP 3 & 4 (Table 2.4S.6-5). The simulations indicate that a landslide tsunami originating from the East Breaks slump location would be unlikely to cross the barrier islands and produce a runup in excess of 2 m (6.56 ft) MSL. Plots of maximum wave amplitude relative to South Texas coast bathymetry are shown for PV, PV(x20), PNG, and the hypothetical “Monster” cases in Figure 2.4S.6-15, Figure 2.4S.6-17, Figure 2.4S.6-19, and Figure 2.4S.6-21, respectively. Time series of wave amplitude for a buoy located near the South Texas Coast for the PV, PV(x20), PNG, and hypothetical “Monster” are shown in Figure 2.4S.6-16, Figure 2.4S.6-18, Figure 2.4S.6-20, and Figure 2.4S.6-22, respectively. Maximum drawdown was estimated at a buoy located at depth of 8.1 m and approximately 1 mi offshore of the South Texas coast (Figure 2.4S.6-4). At this location, significant drawdown of the water surface below MSL occurred for initial negative waves for the PV(x20) and hypothetical “Monster” scenarios. Maximum drawdown for the PV(x20) case had a duration of about 21 minutes, with a peak negative wave elevation of about -1.5 m (-4.9 ft) (Figure 2.4S.6-18). Maximum drawdown (i.e., below MSL) for the hypothetical “Monster” case had a duration of about 23 minutes, with a peak negative wave elevation of about -2.5 m (-8.2 ft) (Figure 2.4S.6-22). Therefore, maximum drawdown levels are not expected to impact any safety-related facilities at STP 3 & 4. 2.4S.6.5 Tsunami Water Levels Reference 2.4S.6-3 (p. 34) stated that subaerial landslides, volcanogenic sources, and nearfield intraplate earthquakes are unlikely to be the causative tsunami generator for damaging tsunamis in the Gulf of Mexico region. Reference 2.4S.6-3 also stated that far-field “tsunamis generated by earthquakes do not appear to impact the Gulf of Mexico coast.” Simulations by Reference 2.4S.6-4 of postulated “worst-case” seismic events reported a tsunami near STP 3 & 4 with a shoreline amplitude of 0.15 m. As far-field tsunamis are unlikely to impact the South Texas coast, the PMT for STP Subsection 2.4S.6 is defined as a tsunami occurring from a near-field submarine landslide near the East Breaks slump. Using the MOST code (Reference 2.4S.6-8), a series of scaled initial conditions were used to assess the near-field hazard of tsunami generation from submarine landslides to the STP 3 & 4 site. For scenarios with wave heights ranging from - 140 m (-459 ft) to 60 m (197 ft) and deformation areas ranging from 410 km2 to 9932 km2, tsunami waves from the SMFs were diffused rapidly by the continental shelf offshore of the South Texas coast. The remaining wave energy that reached the South Texas coast was largely reflected by the barrier islands. For example, maximum predicted runup from the simulations did not exceed 2 m. Maximum flow depth from the simulations, which occurred at the shoreline, did not exceed 3.25 m. Maximum rundown did not exceed 2.5 m about 1 mi offshore of the South Texas coast. 2.4S.6-14 Probable Maximum Tsunami Hazards Rev. 12 STP 3 & 4 Final Safety Analysis Report The initial deformation conditions listed in Table 2.4S.6-5 plausibly exceed wave heights from propagating tsunamis that may occur due to landslides in remote areas of the Gulf of Mexico. For example, relative to the location of STP 3 & 4, most SMF sources in the Gulf of Mexico are mid-field to far-field sources (i.e., source locations over 200 km away) (Figure 2.4S.6-3). The distance from STP 3 & 4 to the East Breaks slump is 142 km (88.2 mi). The distance from STP 3 & 4 to Bryant Canyon is 517 km (321.2 mi). The distance from STP 3 & 4 to Mississippi Canyon and the Eastern Mississippi Canyon/Fan is 640 km (397.7 mi) and 709 km (440.6 mi), respectively. The distance from STP 3 & 4 to the Campeche Escarpment and Bay of Campeche is 873 km (542.5 mi) and 953 km (592.2 mi), respectively. The distance from STP 3 & 4 to the Florida escarpment is 1169 km (726.4 mi). Since landslide waves tend to be steep (i.e., high initial wave height relative to wavelength) and are prone to breaking, wave heights at the East Breaks slump from mid-field and far-field sources are not expected to exceed the simulated initial conditions. As shown with the simulations, diffusion and energy dissipation from large SMF events is likely to be significant. Therefore, potential runup from these events is likely to be lower than the scenarios modeled for the East Breaks slump, and additional landslide scenarios in the Gulf of Mexico are not further considered. As discussed earlier, the maximum flood level for a PMT event also included an analysis of the 10% exceedance of the astronomical high tide and long-term sea level rise. As regulatory criteria for these components are only available for the Probable Maximum Storm Surge (PMSS), the criteria for the PMSS in Regulatory Guide 1.59 (1977) (Reference 2.4S.6-15) were adopted for the PMT analysis. Based on tide gage data for NOS Station #8772440, the 10% exceedance of the astronomical high tide was estimated to be 3.54 ft MSL (Reference 2.4S.6-16). The long-term sea level rise for this station was estimated by NOAA to be 1.43 ft per century (Reference 2.4S.6- 17). The peak flood level due to a probable maximum tsunami event is therefore estimated to be of the order of 11.5 ft MSL within the next century. With respect to the assumption of the MSL datum (or NGVD 29) shift relative to actual mean sea level from tidal measurements, it should be noted that the Freeport, Texas, tide gage does not have a published or official NGVD29 orthometric height mark. Since the one mark that does exist suggests the difference between MSL (or NGVD 29) to actual mean sea level is small (i.e., within ±0.2 ft of the Mean Lower-Low Water datum), the shift to MSL (or NGVD 29) should be considered as a reasonable approximation of the actual value. Based on the discussion above, it is concluded that the flood elevation at STP 3 & 4 due to the postulated probable maximum tsunami event will not be the controlling design basis flood event for STP 3 & 4 because the postulated flood level is lower than the design basis flood elevation of 40.0 feet MSL established based on a hypothetical breach event of the MCR embankment as described in Section 2.4S.4. Coincident wind waves are not considered in the analysis since it is evident that the PMT event will have no flooding impacts on safety-related facilities of STP 3 & 4. Probable Maximum Tsunami Hazards 2.4S.6-15 Rev. 12 STP 3 & 4 Final Safety Analysis Report 2.4S.6.6 Hydrography and Harbor or Breakwater Influences on Tsunami Because the STP 3 & 4 site is over fifteen miles inland from the South Texas coast and barrier islands, and the postulated maximum flood level of no more than 11.5 ft MSL due to the PMT event is lower than the site grade elevations of 32 ft MSL to 36.6 ft MSL for the power block area of STP 3 & 4, there will be no local onsite effects associated with different tsunami types, including breaking waves, bores, or any resonance effects that would result in higher tsunami runup on the safety-related facilities. Therefore, no additional analysis of the translation of tsunami waves from offshore generator locations to the site is warranted. 2.4S.6.7 Effects on Safety-Related Facilities The postulated maximum flood level of no more than 11.5 ft MSL due to the PMT event is lower than the site grade elevations of 32 ft MSL to 36.6 ft MSL for the power block area of STP 3 & 4. Therefore, the PMT event will have no flooding impacts on safety- related facilities or the design basis functions of STP 3 & 4, and there will be no impact of debris and water-borne projectiles and impacts of sediment erosion and deposition on the safety-related facilities of STP 3 & 4. 2.4S.6-16 Probable Maximum Tsunami Hazards Rev. 12 STP 3 & 4 Final Safety Analysis Report 2.4S.6.8 References 2.4S.6-1 “Tsunami Hazard Assessment at Nuclear Power Plant Sites in the United States of America,” Prasad, R. and Pacific Northwest National Laboratory (PNNL), NUREG CR-6966, PNNL-17397, Nuclear Regulatory Commission, Draft Report for Comment, Revision: August 2008. 2.4S.6-2 “Scientific and Technical Issues in Tsunami Hazard Assessment of Nuclear Power Plant Sites,” González et al., F.I., Bernard, E., Dunbar, P., Geist, E., Jaffe, B., Kanoglu, U., Locat, J., Mofjeld, H., Moore, A., Synolakis, C.E., Titov, V. and R. Weiss (Science Review Working Group), National Oceanic and Atmospheric Administration (NOAA) Technical Memorandum OAR Pacific Marine Environmental Laboratory 136, 2007. 2.4S.6-3 “Evaluation of Tsunami Sources with the Potential to Impact the U.S. Atlantic and Gulf Coasts - A Report to the Nuclear Regulatory Commission: U.S. Geological Survey Administrative Report,” Atlantic and Gulf of Mexico Tsunami Hazard Assessment Group, Revision: August 22, 2008. 2.4S.6-4 “Model Predictions of Gulf and Southern Atlantic Coast Tsunami Impacts from a Distribution of Sources,” Knight, B. 2006, Science of Tsunami Hazards 24(2): 304-312. 2.4S.6-5 “Cumbre Vieja Volcano - Potential Collapse and Tsunami at La Palma, Canary Islands,” Ward, S. N. and S. Day. 2001. Geophysical Research Letters 28(17): 3397-3400. 2.4S.6-6 “Geomorphology and age of the Oxygen isotope stage 2 (last lowstand) sequence boundary on the northwestern Gulf of Mexico continental shelf," Simms, A.R., Anderson, J.B., Milliken, K.T., Taha, Z.P., Wellner, in Seismic Geomorphology: Applications to Hydrocarbon Exploration and Production, Davies, R.J. , Posamentier, H.W., Wood, L. J. & Cartwright, J. A. (eds.), Geological Society, London, Special Publications, 277: 29-46, 2007. 2.4S.6-7 "Sedimentary Features of the South Texas Continental Slope as Revealed by Side-Scan Sonar and High-Resolution Seismic Data,” Rothwell, R.G., Kenyon, N.H. and B.A. McGregor, The American Association of Petroleum Geologists Bulletin 75(2): 298-312, 1991. 2.4S.6-8 “Implementation and testing of the Method of Splitting Tsunami (MOST) model,” Titov, V.V., and F.I. González et al., NOAA Technical Memorandum ERL PMEL112, Pacific Marine Environmental Laboratory, 1997. 2.4S.6-9 “Tsunami Science Before and Beyond Boxing Day 2004,” Synolakis, C.E. and E.N. Bernard, Philosophical Transactions of the Royal Society 64: 2231-2265, 2006. Probable Maximum Tsunami Hazards 2.4S.6-17 Rev. 12 STP 3 & 4 Final Safety Analysis Report 2.4S.6-10 “Tsunami Features of Solid Block Underwater Landslides,” Watts, P., Journal of Waterway, Port, Coastal, and Ocean Engineering 126(3): 144- 152, 2000. 2.4S.6-11 “Tsunami Generation by Submarine Mass Failure, Part II, Predictive Equations and Case Studies,” Watts, P., Grilli, S.T., Tappin, D.R. and G.J. Fryer, Journal of Waterway, Port, Coastal, and Ocean Engineering 131(6): 298-310, 2005. 2.4S.6-12 “Tsunami Hazards in Southern California,” Borrero, J.C., Ph.D. Thesis, University of Southern California, 2002. 2.4S.6-13 “The Slump Origin of the 1998 Papua New Guinea Tsunami,” Synolakis, C.E., Bardet, J.-P., Borrero, J.C., Davies, H.L., Okal, E.A., Silver, E.A., Sweet, S., and D.R. Tappin, Proceedings: Mathematical, Physical and Engineering Sciences 458(2020): 763-789, 2002. 2.4S.6-14 “Tsunami and Seiche,” Synolakis, C. E. 2004 from Earthquake Engineering Handbook, edited by Chen, W. F. and C. Scawthorn, CRC Press. 9-1 to 9- 90. 2.4S.6-15 “Design Basis Floods for Nuclear Power Plants,” U.S. Nuclear Regulatory Commission, Regulatory Guide 1.59, Revision 2, 1977. 2.4S.6-16 “NOS Station #8772440, Freeport - Verified Historic Tide Data,” National Oceanic and Atmospheric Administration (NOAA), available at http://tidesandcurrents.noaa.gov/data_menu.shtml?stn=8772440%20Free port,%20 TX&type=Historic+Tide+Data, accessed August 19, 2008. 2.4S.6-17 “NOS Station #8772440, Freeport - Sea Level Trends,” National Oceanic and Atmospheric Administration (NOAA), 2008, available at http://tidesandcurrents.noaa.gov/sltrends/sltrends_station.shtml?stnid=87 72440%2 0Freeport,%20TX, accessed August 19, 2008. 2.4S.6-18 “Tsunami Data at NGDC,” National Geophysical Data Center/World Data Center. Available at http://www.ngdc.noaa.gov/hazard/tsu.shtml, accessed November 22, 2008. 2.4S.6-19 “Caribbean Tsunamis: A 500-Year History from 1498-1999. Kluwer Academic Publishers,” O' Loughlin, K. F. and J. F. Lander. 2003. The Netherlands. 280 pp. 2.4S.6-20 “Tsunamis and Tsunami-Like Waves of the Eastern United States,” Science of Tsunami Hazards 20(3): 120-157, Lockridge, P. A., Lowell, S. W., and J. F. Lander. 2002. 2.4S.6-21 “Improving Earthquake and Tsunami Warnings for the Caribbean Sea, the Gulf of Mexico, and the Atlantic Coast,” USGS Fact Sheet 2006-3012, United States Geological Survey, 2006. 2.4S.6-18 Probable Maximum Tsunami Hazards Rev. 12 STP 3 & 4 Final Safety Analysis Report 2.4S.6-22 “NOAA Center for Tsunami Research,” Pacific Marine Environmental Laboratory (PMEL). Available at http://nctr.pmel.noaa.gov/, accessed November 23, 2008. 2.4S.6-23 “A Brief History of Tsunamis in the Caribbean Sea. Science of Tsunami Hazards,” 20(2): 57-94, Lander, J. F., Whiteside, L. S., and P. A. Lockridge, 2002. 2.4S.6-24 “Unusual Tide Registration of Earthquake,”Parker, W.E. 1922. Bulletin of the Seismological Society in America, pp. 28-30. 2.4S.6-25 “Earthquake History of Puerto Rico, Seismicity Investigation,” Appendix I, Part A, An Earthquake History of Puerto Rico, Aguirre Nuclear Power Plant, Weston Geophysical Research,” Campbell, J.B., 1972, Weston, Massachusetts. 2.4S.6-26 “Alaska Earthquake of 27 March 1964: Remote Seiche Stimulation. Science 145: 261-262,” Donn, W. L. 1964. 2.4S.6-27 “Historical Earthquakes, Prince William Sound, Alaska,” United States Geological Survey, Available at http://earthquake.usgs.gov/regional/states/events/ 1964_03_28.php, accessed April 27, 2007. 2.4S.6-28 “Seismic Seiches in Bays, Channels, and Estuaries, from The Great Alaska Earthquake of 1964: Oceanography and Coastal Engineering,” McGarr, A. and R. C. Vorhis. 1972, National Academy of Sciences, Washington, D.C. 25-28. 2.4S.6-29 “Assessment of Source Probabilities for Potential Tsunamis Affecting the U.S. Atlantic Coast,” Parsons, T., Geist, E.L., in press, Marine Geology, doi:10.1016/j.margeo.2008.08.005. 2.4S.6-30 ”Global Centroid Moment Tensor (CMT),” Available at http://www.globalcmt.org/, accessed November 21, 2008. 2.4S.6-31 “Numerical Modeling of the Global Tsunami: Indonesian Tsunami of 26 December 2004”, Kowalik, Z., Knight, W., Logan, T. and P. Whitmore, Science of Tsunami Hazards 23(1): 40-56, 2005. 2.4S.6-32 “Surface Deformation Due to Shear and Tensile Faults in a Half-Space,” Okada, Y., Bulletin of the Seismological Society of America 75(4): 1135- 1154, 1985. 2.4S.6-33 “Magnitude 5.8 Gulf of Mexico Earthquake of 10 September 2006,” National Earthquake Information Center, United States Geological Survey, Available at http://earthquake.usgs.gov/eqcenter/eqinthenews/2006/usslav/#summary, accessed December 02, 2008. Probable Maximum Tsunami Hazards 2.4S.6-19 Rev. 12 STP 3 & 4 Final Safety Analysis Report 2.4S.6-34 “Magnitudes and locations of the 1811-1812 New Madrid, Missouri, and the 1886 Charleston, South Carolina, Earthquakes,” Bakun, W. H. and M. G. Hopper. 2004. Bulletin of the Seismological Society of America 94(1): 64- 75. 2.4S.6-35 “Modeling the La Palma Landslide Tsunami,” Mader, C.L., Science of Tsunami Hazards 19(3): 150-170, 2001. 2.4S.6-36 “SAGE calculations of the tsunami threat from La Palma,” Gisler, G., Weaver, R. and M.L. Gittings, 2006, Science of Tsunami Hazards 24(4): 288-301. 2.4S.6-37 “The Threat Posed by the Tsunami to the UK,” British Geology Society, 2005. Study commissioned by Debra Flood Management, 133 pp. 2.4S.6-38 “Addressing the Challenges in the Placement of Seafloor Infrastructure on the East Breaks Slide-A Case Study: The Falcon Field (EB 579/623),” Hoffman, J.S., Kaluza, M.J., Griffiths, R., Hall, J. and T. Nguyen, Northwestern Gulf of Mexico, Offshore Technology Conference 16748, 2004. 2.4S.6-39 “Downslope Sediment Transport Processes and Sediment Distributions at the East Breaks, northwest Gulf of Mexico,” Piper, J.N., and Behrens, in Proceedings of the 23rd Annual Gulf Coast Section SEPM Research Conference, Houston, Texas, pp. 359-385, 2003. 2.4S.6-40 “East Breaks Slump, Northwest Gulf of Mexico,” Offshore Technology Conference, OTC paper 12960, Trabant, P., Watts, P., Lettieri, F. and G. Jamieson. 2001. 2.4S.6-41 National Geophysical Data Center (NGDC), 2008, “Bathymetry, Topography, and Relief,” National Oceanic and Atmospheric Administration (NOAA), available at http://www.ngdc.noaa.gov/mgg/bathymetry/relief.html, accessed October 5, 2008. 2.4S.6-42 Titov, V.V. and C.E. Synolakis, 1998, “Numerical Modeling of Tidal Wave Runup,” Journal of Waterway, Port, Coastal, and Ocean Engineering 124(4): 157- 171. 2.4S.6-43 Titov, V.V., 1997, Numerical Modeling of Long Wave Runup, Ph.D. Thesis, University of Southern California, Los Angeles, California, 141 pp. 2.4S.6-20 Probable Maximum Tsunami Hazards Rev. 12 STP 3 & 4 Final Safety Analysis Report Table 2.4S.6-1 Approximate range of tsunami parameters in the deep ocean (Reference 2.4S.6-2). Parameter Minimum Maximum Depth 1000 m 5000 m Period 5 min 60 min Amplitude 0.01 m 1 m Wavelength 30 km 800 km Speed 0.10 km/s 0.22 km/s Max Current 0.05 cm/s 9.9 cm/s Table 2.4S.6-2 Approximate range of tsunami parameters in shallow water (Reference 2.4S.6-2). Parameter Minimum Maximum Depth 10 m 1000 m Period 5 min 60 min Amplitude 1 m 10 m Wavelength 3 km 356 km Speed 0.01 km/s 0.10 km/s Max Current 9.9 cm/s 990 cm/s Table 2.4S.6-3 Areas of potential seismic tsunamigenesis in the Caribbean (Reference 2.4S.6-3, pp. 105 and 107). Caribbean Source Latitude (° N) Longitude (° W) North Panama Deformation Belt 9-12 83-77 Northern South American 11.5-14 77-64 Convergent Zone Table 2.4S.6-4 Source parameters for Veracruz scenario. Rupture Length Width Depth Strike Dip Rake Max slip Epicenter Mw (km) (km) (km) (°) (°) (°) (m) 20° N, 8.2 200 70 5 135 20 90 2 265° E Probable Maximum Tsunami Hazards 2.4S.6-21 Rev. 12 STP 3 & 4 Final Safety Analysis Report Table 2.4S.6-5 Initial wave deformation characteristics and maximum runup for simulations. Deformation Dipole Initial Dipole Initial Maximum Area Minimum Maximum Runup Figure Case (sq. km) (m below MSL) (m below MSL) (m above MSL) Reference PV 411 -7 3 1 2.4S.6-7; 2.4S.6-8 PV(x20) 387 -140 60 2 2.4S.6-9; 2.4S.6-10 PNG 879 -20 16 2 2.4S.6-11; 2.4S.6-12 Monster 9932 -38 27 2 2.4S.6-13; 2.4S.6-14 2.4S.6-22 Probable Maximum Tsunami Hazards Rev. 12 STP 3 & 4 Final Safety Analysis Report Figure 2.4S.6-1 Location Map of STP 3 & 4 from the Gulf Coast and Colorado River. Probable Maximum Tsunami Hazards 2.4S.6-23 Rev. 12 STP 3 & 4 Final Safety Analysis Report i-Generating Earthquakes from 1530-1991 in the Caribbean Sea the Caribbean in 1530-1991 from Earthquakes i-Generating (modified from Reference 2.4S.6-21). Reference from (modified Figure 2.4S.6-2 Regional Map of Plate Boundaries and Tsunam Boundaries Map of Plate Regional Figure 2.4S.6-2 2.4S.6-24 Probable Maximum Tsunami Hazards Rev. 12 STP 3 & 4 Final Safety Analysis Report field landslide source. Source of bathymetry: Reference 2.4S.6-41. Reference of bathymetry: Source source. field landslide Figure 2.4S.6-3 Landslide source regions in Gulf of Mexico. At 142 km from STP 3 & 4, the East Breaks slump is the only near- is the slump Breaks & 4, the East 3 STP km from At 142 of Mexico. Gulf in regions source Landslide 2.4S.6-3 Figure Probable Maximum Tsunami Hazards 2.4S.6-25 Rev. 12 STP 3 & 4 Final Safety Analysis Report Figure 2.4S.6-4 Location of East Breaks slump relative to STP 3 & 4 (Source: Reference 2.4S.6-41). Buoy record for recording tsunami wave amplitudes is located at 28.58° N and 95.98° W. Bathymetry elevations are relative to Mean Sea Level (MSL). 2.4S.6-26 Probable Maximum Tsunami Hazards Rev. 12 STP 3 & 4 Final Safety Analysis Report data: Reference 2.4S.6-41) data: Reference thymetry elevations are relative to MSL. (Source of bathymetry bathymetry to MSL. (Source of are relative elevations - Ba thymetry slump for East Breaks Source parameters 2.4S.6-5 Figure Probable Maximum Tsunami Hazards 2.4S.6-27 Rev. 12 STP 3 & 4 Final Safety Analysis Report bathymetry data: Reference 2.4S.6-41) data: Reference bathymetry Figure 2.4S.6-6 Grid spacing for East Breaks slump modeling with MOST. Bathymetry elevations are relative to MSL. (Source of (Source of to MSL. relative are elevations Bathymetry MOST. with modeling slump Breaks for East spacing Grid 2.4S.6-6 Figure 2.4S.6-28 Probable Maximum Tsunami Hazards Rev. 12 STP 3 & 4 Final Safety Analysis Report Figure 2.4S.6-7 Plan view of Palos Verdes (PV) initial deformation condition at location of the East Breaks slump in the Gulf of Mexico. Elevations of initial wave correspond with elevations in Figure 2.4S.6-8. Probable Maximum Tsunami Hazards 2.4S.6-29 Rev. 12 STP 3 & 4 Final Safety Analysis Report Figure 2.4S.6-8 Side view of Palos Verdes (PV) initial deformation condition. Maximum elevation of negative wave is -7 m (MSL); maximum elevation of positive wave is +3 m. (MSL). Source: Reference 2.4S.6-5, p. 5 2.4S.6-30 Probable Maximum Tsunami Hazards Rev. 12 STP 3 & 4 Final Safety Analysis Report Figure 2.4S.6-9 Plan view of Palos Verdes x20 (PVx20) initial deformation condition at location of the East Breaks slump in the Gulf of Mexico. Elevations of initial wave correspond with elevations in Figure 2.4S.6-10. Probable Maximum Tsunami Hazards 2.4S.6-31 Rev. 12 STP 3 & 4 Final Safety Analysis Report Figure 2.4S.6-10 Side view of Palos Verdes x20 (PVx20) initial deformation condition. Maximum elevation of negative wave is -140 m (MSL); maximum elevation of positive wave is +60 m (MSL). 2.4S.6-32 Probable Maximum Tsunami Hazards Rev. 12 STP 3 & 4 Final Safety Analysis Report Figure 2.4S.6-11 Plan view of Papua New Guinea (PNG) initial deformation condition at location of the East Breaks slump in the Gulf of Mexico. Elevations of initial wave correspond with elevations in Figure 2.4S.6-12. Probable Maximum Tsunami Hazards 2.4S.6-33 Rev. 12 STP 3 & 4 Final Safety Analysis Report Figure 2.4S.6-12 Plan view of Papua New Guinea (PNG) initial deformation condition. Maximum elevation of negative wave is -18 m (MSL); maximum elevation of positive wave is +16 m (MSL). 2.4S.6-34 Probable Maximum Tsunami Hazards Rev. 12 STP 3 & 4 Final Safety Analysis Report Figure 2.4S.6-13 Plan view of hypothetical “Monster” initial deformation condition at location of the East Breaks slump in the Gulf of Mexico. Elevations of initial wave correspond with elevations in Figure 2.4S.6-14. Probable Maximum Tsunami Hazards 2.4S.6-35 Rev. 12 STP 3 & 4 Final Safety Analysis Report Figure 2.4S.6-14 Oblique view of hypothetical “Monster” initial deformation condition. Maximum elevation of negative wave is -38 m (MSL); maximum elevation of positive wave is +28 m (MSL). 2.4S.6-36 Probable Maximum Tsunami Hazards Rev. 12 STP 3 & 4 Final Safety Analysis Report Figure 2.4S.6-15 Maximum coastal runup for the PV simulation was 1 m. Probable Maximum Tsunami Hazards 2.4S.6-37 Rev. 12 STP 3 & 4 Final Safety Analysis Report Figure 2.4S.6-16 Time series of wave amplitude for PV simulation at 28.58° N and 95.98° W (i.e., buoy location shown in Figure 2.4S.6-4). Datum referenced to MSL. 2.4S.6-38 Probable Maximum Tsunami Hazards Rev. 12 STP 3 & 4 Final Safety Analysis Report Figure 2.4S.6-17 Maximum coastal runup for the PVx20 simulation was 2 m. Probable Maximum Tsunami Hazards 2.4S.6-39 Rev. 12 STP 3 & 4 Final Safety Analysis Report Figure 2.4S.6-18 Time series of wave amplitude for PVx20 simulation at 28.58° N and 95.98° W (i.e., buoy location shown in Figure 2.4S.6-4). Datum referenced to MSL. 2.4S.6-40 Probable Maximum Tsunami Hazards Rev. 12 STP 3 & 4 Final Safety Analysis Report Figure 2.4S.6-19 Maximum coastal runup for the PNG simulation was 2 m. Probable Maximum Tsunami Hazards 2.4S.6-41 Rev. 12 STP 3 & 4 Final Safety Analysis Report Figure 2.4S.6-20 Time series of wave amplitude for PNG simulation at 28.58° N and 95.98° W (i.e., buoy location shown in Figure 2.4S.6-4). Datum referenced to MSL. 2.4S.6-42 Probable Maximum Tsunami Hazards Rev. 12 STP 3 & 4 Final Safety Analysis Report Figure 2.4S.6-21 Maximum coastal runup for the hypothetical “Monster” simulation was 2m. Probable Maximum Tsunami Hazards 2.4S.6-43 Rev. 12 STP 3 & 4 Final Safety Analysis Report Figure 2.4S.6-22 Time series of wave amplitude for hypothetical “Monster” simulation at 28.58° N and 95.98° W (i.e., buoy location shown in Figure 2.4S.6-4). Datum referenced to MSL. 2.4S.6-44 Probable Maximum Tsunami Hazards