Clinch River Nuclear Site SPA, Seismic-Geotechnical Audit

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AUDIT PLAN FOR AREAS COVERED IN SECTION 2.5 OF THE SITE SAFETY ANALYSIS REPORT, CLINCH RIVER NUCLEAR SITE EARLY SITE PERMIT APPLICATION

APPLICANT: Tennessee Valley Authority (TVA)

DATES: May 8-9, 2017

LOCATIONS: TVA Knoxville Office Complex 400 West Summit Hill Drive Knoxville, Tennessee 37902

Clinch River Nuclear Site Oak Ridge, Tennessee

AUDIT TEAM: David Heeszel, Team Leader (NRO/DSEA/RGS) Alice Stieve (NRO/DSEA/RGS) Weijun Wang (NRO/DSEA/RGS) Ricardo Rodriguez (NRO/DSEA/RGS) Laurel Bauer (NRO/DSEA/RGS)

PROJECT MANAGER: Allen Fetter (NRO/DNRL/LB3)

BACKGROUND AND AUDIT OBJECTIVE

In conjunction with the information audit, which will take place at the TVA Knoxville Office, most members of the NRC staff will visit the CRN site and surrounding area in an effort to become familiar with the site layout, the surrounding geologic and tectonic features, and the site physiography. At the CRN Site, NRC staff will also have the opportunity to examine geologic core samples collected during site investigations. Both venues will provide the staff an opportunity to discuss the information needs identified during the staff’s initial review of the application and associated SSAR sections with TVA’s subject matter experts (SMEs), staff and contractors. During the audit, the staff will review and discuss probabilistic seismic hazard analysis evaluations methodology, and karst formation evaluation proposed in the SSAR, as well as associated calculation packages and supporting modeling documentation (as needed). The audit will allow the NRC staff to better understand the CRN site and applicant’s modeling results. The audit will also assist the NRC staff in identifying any subsequent requests for additional information needed so that the staff can conduct a complete review of the CRNS ESP application and make appropriate safety conclusions concerning site characteristics and site suitability.

REGULATORY AUDIT BASES

This regulatory audit is based on the following:

• NUREG 0800, “Standard Review Plan”

• Regulatory Guide (RG) 1.206, “Combined License Applications for Nuclear Power Plants”

• 10 CFR 100.23, “Geologic and Seismic Siting Criteria”

• 10 CFR 52.17 Contents of Applications; Technical Information, subparts (a)(1)(ii) and (a)(1)(vi)

• 10 CFR Part 50, Appendix A, General Design Criterion 2

AUDIT ACTIVITIES AND SCHEDULE

The NRC staff will conduct the review over a period of two business days, May 8-9, 2017. If necessary, the audit can be extended until noon May 10, 2017. The need for an extension will be determined by the NRC staff responsible for the audit before the planned adjournment of the meeting on May 9th.

An agenda for the audit is presented in Attachment A. Attachment B contains specific information needs for each review section. If necessary, any circumstances related to the conductance of the audit will be communicated to the safety project manager, Allen Fetter (NRC), at 301 415-8556 or at [email protected].

DELIVERABLES

The audit team plans to issue an audit report within 90 days after completing the audit.

1SSAR and Electronic Reading Room documents should be available to facilitate discussion. 2Seismologists and Geotechnical Engineers only need to see prospective sites within the boundary. 2 ATTACHMENT A

AGENDA Tennessee Valley Authority (TVA) Clinch River Nuclear (CRN) Early Site Permit Site Audit Pertaining to the Review of the Clinch River Site Safety Analysis Report, Section 2.5 TVA Knoxville Office, Knoxville, Tennessee TVA CRN Proposed Site, Oak Ridge, Tennessee

Monday, May 8, 2017, MORNING SESSION: AUDIT - Proprietary 8:30 a.m. - 8:45 a.m. Audit Entrance / Introduction [NRC/TVA] 8:45 a.m. - 12:00 p.m. Documentation Review and Discussion: Methodology for seismic calculations and analysis, void formation evaluation and associated calculations1 [NRC/TVA] 12:00 p.m. - 1:00 p.m. Lunch Monday, May 8, 2017, AFTERNOON SESSION: AUDIT - proprietary 1:00 p.m. - 4:30 p.m. Documentation Review and Discussion continued and field trip for geology review [NRC/TVA] 4:30 p.m. - 4:45 p.m. NRC Internal Caucus [NRC] 4:45 p.m. - 5:00 p.m. Debrief Summary [NRC/TVA] 5:00 p.m. Adjourn

Tuesday, May 9, 2017, MORNING SESSION: AUDIT - proprietary 9:00 a.m. - 12:15 p.m. Site Tour Examinations of cores/samples, area/vicinity geologic features [NRC/TVA] 12:15 p.m.- 1:00 p.m. Lunch Tuesday, May 9, 2017, AFTERNOON SESSION: AUDIT - proprietary 1:00 p.m. - 4:30 p.m. Site Tour (area/vicinity geologic features continued) 2 [NRC/TVA] 4:30 p.m. - 4:45 p.m. NRC Internal Caucus [NRC] 4:45 p.m. - 5:00 p.m. Audit Exit [NRC/TVA] 5:00 p.m. Adjourn

ATTACHMENT B

Information Needs Specific To Site Safety Analysis Report Sections 2.5.1 Geologic Information Field trip to visit features described in Site Safety Analysis Report (SSAR) text or illustrated in SSAR figures (if possible): 1. Visit the surface projection location of Shear Fracture Zone on site (Figure 2.5.1-65) and across the river if that location is accessible and currently exposed as indicated in CNL- 16-162, p E1-36.

2. Visit location of Chestnut Ridge and Copper Creek faults in site location.

3. Visit Quaternary deposits and landforms (terraces) in site area.

4. Visit 2 Sinkhole clusters on site (northern boundary) and to the SE (as indicated on fig 2.5.1-46)

5. Visit pinnacle and cutter exposure near Copper Ridge Cave (fig 2.5.1-40), an abandoned phreatic cave within site area. Visit both the hillside exposure and the cave. Examine specific core for: 1. Examples of shear fracture zone and other fracture zones (to distinguish the difference between shear fracture zones from fracture zones) in boreholes: 21 ft. in MP 423 (718- 697 ft. elev, runs 13,14,15,16,17,18);18 and 6 ft in MP 201 (644-626 ft elev, runs 27,28,29,30) and (497-491 ft elev, runs 56 & 57)); and 6 ft in MP 101 (553-547 ft elev, runs 47, 48), based on information from Tables 2.5.1-16 and -17.

2. Examples of open voids in boreholes (information from ESP Table 2.5.1-11) MP 418 (void at ~ 756 and ~735 ft elev)

3. Examples of clay or soil filled voids as described in CNL-16-162:

CNL-16-162, pE2-17: A number of the cavities encountered in the boreholes were partially to completely filled with clay or soil.

4. Examples of Knox unconformity (Blackford/Knox contact) from borehole MP 201, suggest 305-315 ft depth, and MP 423 suggest 275-280 ft depth, based on information in ESP SSAR Table 2.5.1-2

Discussion topics: Discuss your evaluation of landslide hazard at the site location in consideration of SSAR Section 2.5.3.8.2.2 and regional scale Figures 2.5.1-22 & 2.4.9-5 Discuss information in Tables 2.5.1-16 and 2.5.1-17. .

ATTACHMENT B

Information Needs SpecificTo Site Safety Analysi Report Sections

2.5.2 Vibratory Ground Motion Discussion topics: Discuss how rates and recurrence values for the Eastern Tennessee Seismic Zone (ETSZ ) are considered in CEUS-SSC (Central and Eastern United States – Seismic Source Characterization) and how the treatment of the ETSZ distributed seismicity might impact the site-specific PSHA (Probabilistic Seismic Hazard Analysis) Discuss development of 1-D site response analysis profiles in consideration of local geology (e.g. single velocity profile adjusted up or down vs depth or formation specific velocity profile). Discuss total site variablility considered in site response in comparison to the total observed variability in geophysical data collected at the site. 2.5.4 Geotechnical Engineering Examine specific core/sample for: Borings MP101, MP201, and MP202 with emphasis on shear fracture features Discussion Topics: Plaxis model calculation package Bearing capacity and settlement packages Discuss the material in Section 2.5.1.2.3.4 Estimation of hypothetical large void in consideration of the material in the Rizzo Report.

1SSAR and Electronic Reading Room documents should be available to facilitate discussion. 2Seismologists and Geotechnical Engineers only need to see prospective sites within the boundary. 2

Field Trip Guidebook NRC Audit Clinch River Nuclear Site Early Site Permit Application May 8-9, 2017

Introduction

Tennessee Valley Authority (TVA) submitted geologic, seismic and geotechnical engineering characterization information to the U.S. Nuclear Regulatory Commission (NRC) as part of their Clinch River Nuclear Site (CRNS) Early Site Permit (ESP) application. NRC staff reviewed the data and information within Section 2.5 of the Site Safety Analysis Report (SSAR), as supplemented, and identified information needs that the staff requires to complete its review. The May 8-9, 2017 audit will allow the NRC staff to better understand the CRNS and applicant’s modeling results. The audit will also assist the NRC staff in identifying any subsequent requests for additional information needed so that the staff can conduct a complete review of the CRNS ESP application and make appropriate safety conclusions concerning site characteristics and site suitability.

This field guide is prepared by TVA to supplement the geologic exposures that will be visited during the field component of the May 8-9, 2017 audit (Figure 1). The intent of this field exercise is to clarify the link between how geologic observations in the field, coupled with an understanding of the processes that form these features, relate to the overall site characterization and modeling that is included in the ESP application for the CRNS.

The primary objectives of this field review are to:  observe and discuss characteristic karst dissolution features at and near the CRNS  visit the mapped traces of Alleghanian Valley and Ridge thrust faults that traverse the site (Copper Creek and Chestnut Ridge faults)  observe rock outcrop along the surface projection of the shear-fracture zone that occurs near the base of the Fleanor formation  visit Quaternary fluvial terraces along the Clinch River in the CRN site area

Day 1 (afternoon May 8, 2017) will focus on karst dissolution features in the eastern portion of the CRN site area. Features include sinkholes, caves, and pinnacle and cutter exposures.

Day 2 (May 9, 2017) will include a tour of features on the CRN site, and will include review of core collected during the subsurface investigation that supports the CNRS ESP application. The day will start with an initial review of several shear-fracture zones identified in rock core; the intent is to demonstrate to NRC staff the features we will be looking for along the projected surface trace of the shear-fracture zone (Stop 2-5).

Figure 1: Geologic map with karst features of area that will be visited during audit field trip. Orange stars denote field trip stops.

Day 1

Depart TVA Knoxville Office Complex. Take I-40 West toward Nashville. In approximately 25.1 mi, take exit 364 TN-95 and turn right (north) onto TN-95. In 0.3 mi, turn right onto White Wing Road. Turn right on Buttermilk Road in approximately 0.1 mi, and continue on Buttermilk Road for approximately 1.2 mi. Turn left onto Woodlawn Road. Continue on Woodlawn Road for approximately 0.3 mi; Stop 1-1 is on the right (southeast).

Stop 1-1: Sinkhole in residential area, southeast side of Woodlawn Road (5 min)

The landscape along Buttermilk Road is dotted with sinkholes developed in the Copper Ridge Dolomite and Chepultepec Dolomite. The map (Figure 2) shows the distribution of sinkholes identified from LiDAR in this area. At the bend in Woodlawn Road, a deep sinkhole is a centerpiece for the front lawn of a home. After rainstorms this sink fills with water which gradually disappears.

Figure 2: Karst features in residential area south of Melton Hill Reservoir.

Continue eastbound on Woodlawn Road for approximately 0.2 mi, turn left to continue on Woodlawn Road. In approximately 1.3 mi, pull over to the right and park. Stop 1-2 is on the south side of the road (opposite of the reservoir), just beyond the tree line.

Stop 1-2: Melton Hill Dam water cave (LUNCH) (45 min)

Hidden under the trees at the base of the hill, the entrance to Melton Hill Dam Water Cave is a spring that discharges water collected from the ridge above (Figure 3). Its presence is evidence of an integrated drainage network deep within the ridge. Sinkholes and depressions on the ridge are entry points to this network.

Figure 3: Entrance to Melton Hill Dam water cave.

Continue westbound on Woodlawn Road for approximately 0.4 mi, turn right onto TN-95. Continue on TN-95 for approximately 0.4 mi, turn right onto Greenway Road. ORNL escort will open the gate and lead the group to Stops 1-3 and 1-4.

Stop 1-3: Copper Ridge Cave (1 hour)

Copper Ridge Cave is a good example of a preserved large relict cave segment in the Knox Group (Rubin and Lemiszki, 1992) (Figure 4). The entrance passage is of vadose origin initiated at the intersection of a joint and a bedding plane (Figure 5). Located at the bottom of a depression, a small stream flows directly into the entrance and down the cave passage, where feeder springs emanate from the rock walls to join the main stream.

The passage trends down-dip and eventually intersects the main phreatic passage (see Figure 6 for karst conduit morphologies). This master passage is tube-shaped, about 30 ft. wide, strike- parallel and roughly horizontal, reflecting phreatic dissolution beneath a former groundwater table (Lemiszki and Zerr, 2013).

Figure 4: Stop locations in the Copper Ridge area.

Figure 5: Entrance to Copper Ridge Cave.

Figure 6: Characteristic karst conduit morphology.

Stop 1-4: Pinnacle and cutter exposures along northern slope of Copper Ridge (1 hour)

Soil erosion has exposed this irregular top of bedrock typical of karst areas (Figure 7). Look for evidence on these rock pinnacles of dissolution in four karst zones: the phreatic zone, vadose zone, epikarst zone, and subaerial zone. Each set of characteristic features formed at a different time period, as the rock was gradually brought to the surface through landscape lowering.

Phreatic: Conduits with circular or oval cross sections Vadose: Slot canyons, meandering channels, secondary deposits Epikarst: v-shaped cuttters (a.k.a. slots or grykes), and dome-shaped pinnacles (a.k.a. clints) Subaerial: Sharp-edged solution pits, dissolution pans and basins, vertical rills

Figure 7: Pinnacle and cutter exposures within the Maynardville Limestone. Note hammer for scale in lower right corner.

- - - - END OF DAY 1. RETURN TO KNOXVILLE - - - -

Day 2 – Start at 9:00 am. Meet at entrance to site, 1300 Bear Creek Road.

Figure 8: Stop location map for Day 2.

Stop 2-1: Review specific core to observe shear-fracture zones prior to review of outcrop along projected surface trace (1 hour)

The intent of this stop is to review selected core, specifically to observe shear-fracture zones in the Eidson Member (Fleanor formation) and Rockdell Formation, prior to visiting the natural exposure (Stop 2-5).

Specific core intervals to examine include:  MP-101, Box 16 – SFZ in Rockdell Formation  MP-201, Box 9 – SFZ in Eidson Member

Stop 2-2: Surface trace of Copper Creek fault, near Pleistocene terrace Qpt4 (15 min)

The Copper Creek fault strikes approximately N50°E through the southern portion of the site peninsula (Figure 8). The mapped trace of the fault through the clearing has been flagged for reference (Figure 9). Additionally, the surface of a remnant Pleistocene terrace (Qpt4) is evident, and rounded pebbles, indicative of a fluvial depositional environment, can be found along the northern extent of the terrace surface.

Figure 9: Surface trace of Copper Ridge fault, marked with white flagging.

Stop 2-3: Overview of Holocene terraces along southeastern portion of peninsula (15 min)

At this location, the powerline easement allows access to view several Holocene terraces adjacent to the Clinch River.

Stop 2-4: Sinkhole cluster in the Witten Formation (15-30 min)

The sinkhole complex in the Witten Formation consists of a large dish-shaped closed depression approximately 800 ft long by 300 ft wide, elongated along strike (see Figure 8). The eastern end of this depression contains a steep-sided swallet with a steep bedrock wall, corresponding to the prominent joint set striking N52°E (Figure 10). The western end of the depression is dish-shaped with a flat floor and ponded water after rainstorms. Artificial fill now covers the SW portion of the depression.

Figure 10: Dissolution features in Witten Formation at Stop 2-4. Upper image – steep-sided wall of depression. Lower image – ponded sinkhole.

Stop 2-5: Outcrop along previously mapped surface trace of shear-fracture zone (30-60 min)

During the geologic investigation for the Clinch River Breeder Reactor Project, a surface exposure of the shear zone in their “Unit A Limestone” (now termed “shear-fracture zone” in the lower portion of the Fleanor formation) was reported along the northeastern edge of the site peninsula (Figure 11). At this stop, there is a large outcrop along the road of Fleanor formation limestone and shale, with characteristic elongate nodules and layers of chert (Figure 12). Exposures above the road (to the northwest) are similar in terms of lithology and texture.

Figure 11: Geologic map of Clinch River Breeder Reactor site. Inset shows location of shear zone outcrop in “Unit A Limestone”.

Figure 12: Characteristic exposures of Fleanor formation at Stop 2-5. Upper image – note hammer in lower left for scale. Width of view in lower image is approximately 2 ft. Note dark chert layer in lower image.

Stop 2-6: Sinkhole cluster in the Mascot Dolomite (15-30 min, walk back to vehicles ~15 min)

Mapped and explored during the CRBRP investigations, this cluster of sinkholes is the largest on the site. The CRBRP investigation drilled nine exploratory holes (B-60 through B-68) here. Soil thickness was found to vary markedly, from 2 ft. at the margin of the sinkholes, to as much as 78 ft. within a sinkhole. Solution voids up to four ft. high were encountered below the top of rock. The sink area was found to be aligned along a high-angle northeast striking (N52°E) joint set (PMC, 1982).

- - - - RETURN TO TRAILERS FOR LUNCH AND CORE REVIEW - - - -

Stop 2-7: Surface trace of shear-fracture zone (15-30 min)

The mapped trace of the shear-fracture zone has been flagged for reference. The projected surface trace of this feature strikes approximately N50°E, although as mapped during the Clinch River Breeder Reactor investigation (PMC, 1982), exhibits an irregular map pattern.

Stop 2-8: Surface trace of Chestnut Ridge fault (15-30 min)

The trace of the Chestnut Ridge fault, as mapped by Lemiszki (2015) has been flagged for reference.

- - - - END OF TRIP - - - -

References Cited:

Lauritzen, S-E, and Lundberg, J., 2000, Solutional and erosional morphology, Chapter 6.1 in: Speleogenesis, Evolution of Karst Aquifers, A. B. Klimchouk, D. C. Ford, A. N. Palmer, W. Dreybrodt, National Speleological Society, Inc., 2000, p. 408-426.

Lemiszki, P.J., 2015, Geologic map of the Elverton Quadrangle, Tennessee, TDG Draft Open- File Map, scale 1:24,000.

Lemiszki, P., and Zerr, B., Selected Information on Caves of the Oak Ridge, Tennessee area, Personal communication of unpublished data to Janet Sowers of Fugro Consultants, Inc., 2013. PMC (Project Management Corporation), 1982, Clinch River Breeder Reactor Plant – Preliminary Safety Analysis Report, Volume 3.

Rubin, P. A., and Lemiszki, P. J., Structural and stratigraphic controls on cave development in the Oak Ridge area, Tennessee, in: Gangaware, T., et al., eds., Seventh Tennessee Water Resources Symposium and Student Symposium, Tennessee Section of the American Water Resources Association, Nashville, TN, p. 1-6, 1992.