Lesson Plan Template s38

Occupational Radiation and Contamination Sources

ACADs (08-006) Covered

Keywords

Description

Supporting Material HPT001.009B Revision 3 Page 2 of 42

NUCLEAR TRAINING TRAINING MATERIALS COVERSHEET

RADIOLOGICAL PROTECTION TECHNICIAN INITIAL TRAINING PROGRAM

FUNDAMENTALS TRAINING HPT001 COURSE COURSE NO.

OCCUPATIONAL RADIATION AND CONTAMINATION SOURCES HPT001.009B LESSON TITLE LESSON PLAN NO.

INPO ACCREDITED YES X NO

MULTIPLE SITES AFFECTED YES X NO

PREPARED BY ------Tom Shirley Signature / Date

PROCESS REVIEW ------Phillip D. Prichard Signature / Date

LEAD INSTRUCTOR/PROGRAM MGR. REVIEW ------Sarah Reed Signature / Date

PLANT CONCURRENCE ------Signature / Date

TVAN CONCURRENCE (If applicable) ------BFN SQN WBN CORP Signature / Date

Receipt Inspection and Distribution: Training Materials Coordinator / Date Standardized Training Material Copies to: SQN Technical Training Manager, STC 2T-SQN WBN Technical Training Manager, WTC 1D-WBN BFN Technical Training Manager, BFT 2A-BFN TVA 40385 [NP 6-2001] Page 1 of 2 HPT001.009B Revision 3 Page 3 of 42

NUCLEAR TRAINING REVISION/USAGE LOG

Rev. # Description of Changes Date Pages Affected Reviewed By

0 Initial Issue All

1 Revised to comply with TCA50A All

2 Program was inactive. Reviewed and 3/21/90 All (WTC) revised to reactivate.

3 General revision to update material. 1/31/04 All

TVA 40385 [NP 6-2001] Page 2 of 2 HPT001.009B Revision 3 Page 4 of 42

I. PROGRAM: Radiological Protection Technician Initial Training

II. COURSE: Fundamentals Training

III. LESSON TITLE: Occupational Radiation and Contamination Sources

IV. LENGTH OF LESSON/COURSE: 6 hours

V. TRAINING OBJECTIVES:

A. Terminal Objective:

Upon completion of this course, the participants will demonstrate their knowledge and understanding of the information presented during RADCON Technician training by obtaining a score of greater than or equal to 80% on a written examination. The information presented in this lesson plan may be part of an overall exam or be the only information for which the student is examined. (OH-1)

B. Enabling Objectives:

Standards and conditions apply to all enabling objectives. They include under the examination ground rules, without the use of training materials or outside assistance, and utilizing information presented in this lesson plan. Upon completion of this lesson each participant will be able to:

1. List the origins for sources of radiation in a nuclear power plant. (OH-2) 2. Identify the classification of radionuclides produced in the fission process and where they are produced. 3. Provide an explanation of the fission process and its products. 4. Recognize a fission process with fission fragments and subsequent decay fission products. 5. Define a ternary fission event and its results. (OH-3) 6. Provide a description of fuel rod cladding and its functions. 7. List the types and origins of radiation emitted from the reactor core. 8. Identify the origins of radiation emitted from the reactor coolant. 9. List the types of fission products. (OH-4) 10. Identify the importance of fission products produced. 11. Differentiate the types of fission products by their properties, isotopes, and removal process. 12. Name the origins of activation products. 13. Distinguish activated corrosion products by their origin, properties, isotopes, and removal process. 14. Define “crud” and describe its affect on a PWR and BWR system. 15. Describe activation water oxygen products by the isotopes and radiological hazards. (OH-5) 16. Describe activation water, air and impurities products by the isotopes. HPT001.009B Revision 3 Page 5 of 42

17. Describe activation water chemical products by the chemical added and isotopes produced. 18. Identify the mechanisms for tritium production, its half-life and radiological hazards. 19. Compare sources of radiation in an operational nuclear power plant and a shutdown nuclear power plant. (OH-6) 20. Describe the sources of radiation outside the reactor core and coolant. 21. Define “Hot Spot” and identify potential areas for its occurrence. 22. List the sources of radiation produced outside the plant and brought into the plant environment. (OH-7) 23. Define contamination and explain its sources. 24. Identify “hot particles” by definition and sources. 25. Explain the types of contamination, their potential for exposure and the precautions utilized to limit the potential. 26. Contrast individual occupational dose and collective occupational dose and the reduction of each.

VI. TRAINING AIDS:

A. Computer and projection system with power point capabilities.

VII. TRAINING MATERIALS:

A. Attachment A: HPT001.009B Power point presentation located at: P:\Training\Technical Programs and Services\Radcon\Initial Program\Lesson Plan Library\Library\HPT001.009 B. Appendix 1: 2002 Exposure Data C. Appendix 2: OE – Fuel Defect Operation, Revision 1. D. Appendix 3: OE – Crud Bursts During Station Outages. E. Appendix 4: OE – Radiography. F. Appendix 5: OE – Hot Particle Work Area. G. Appendix 6: OE – Radioactive Filter Handling.

VIII. REFERENCES:

A. Eichholz, Geoffrey G., Environmental Aspects of Nuclear Power, Lewis Publishers, Inc, 1985. B. Martin, Alan and Harbison, Samuel A., An Introduction to Radiation Protection, 3 rd Edition, Chapman and Hall, 1986. C. http://www.science.wisc.edu/neep423/FALL97/lecture24.pdf , Chapter 12 Behavior of Solid Fission products in Oxide Fuel Elements. D. http://www.mcps.org/bhs/classes/dana, Ms. Dana – Chem – Chemical and Physical Properties. E. http://www.amershamhealth.com/medcyclopaedua/Volume1/FISSION PRODUCED RADIONUCLIDE.asp , Fission-produced Radionuclide. HPT001.009B Revision 3 Page 6 of 42

F. Moe, H. L., Operational Health Physics Training, Argonne National Laboratory, 1988. G. Shapiro, Jacob, Radiation Protection – A Guide for Scientist and Physicians-Third Edition, Harvard University Press, 1990. H. Choppin, G. R. and Rydberg, J., Nuclear Chemistry – Theory and Applications, Pergamon Press, 1980. I. http://books.nap.edu/books/NI000156/html, Radiochemistry in Nuclear Power Reactors, The National Academies Press, 1990. J. http://www.ratical.org/radiation/NRBE , Nuclear Radiation and its Biological Effects: The Fissioning Process and its Consequence. K. http://fti.neep.wisc.edu/neep423/FALL97/lecture26.pdf, Chapter13 – Swelling Due to Fission Gas. L. Pentreath R. J., Nuclear Power, Man and the Environment, Taylor & Francis, Ltd., 1980. M. http://www.westrain.org/members/Tech/rp-2.pdf , Radiation Protection Chapter RP- 2. N. http://abulafia.mt.ic.ac.uk/publications/theses/stanek/solutioninuo2.pdf, Chapter 3 Solution of Fission Products in UO2. O. NUREG-0713 Vol.24, Occupational Radiation Exposure at Commercial Nuclear Power Reactors and Other Facilities 2002, U. S. Nuclear Regulatory Commission Office of Nuclear Regulatory Research, 2003.

IX. INTRODUCTION:

As a worker in a nuclear power plant you will be exposed to sources of radiation and contamination. You will need to understand the origins, types, associated risks, and control mechanisms of these sources to minimize you exposure from these sources. As a Radiological Control Technician you will utilize this knowledge to provide guidance to other nuclear power plant workers ensuring minimization of their risk of exposure. HPT001.009B Revision 3 Page 7 of 42

A. The sources of radiation in a nuclear power plant, include those Obj. B1 produced in the plant and those produced outside the plant and brought OH-8 into the plant environment

1. There are two types of radionuclide products. These radionuclides Obj. B2 are classified as fission products and activation products. They OH-9 provide the source of occupational radiation exposure to the workers.

a. The fission process results from the bombardment, by neutrons, Obj. B3 of the U-235 in the fuel pellets. OH-10

b. Each bombardment releases about 200MeV, two nuclei, and OH-11 several energetic neutrons.

c. The nuclei are fission fragments. OH-12

1) Normally fission occurs resulting in two nuclei called fission fragments.

2) The fission fragments usually occur as one light atom and OH-13 one heavy atom.

3) The light atom will have a mass between 72 and110.

4) The heavy atom will have a mass between 110 and 162.

d. There are approximately 80 possible fission fragments. Obj. B4

Examples of the fission process and fission fragment production are:

235 1 141 92 1 92U + 0n → 56Ba + 36Kr + 3 0n + γ OH-14

235 1 140 94 1 92U + 0n → 54Xe + 38Sr + 2 0n + γ OH-15

235 1 142 92 1 92U + 0n → 56Ba + 36Kr + 2 0n + γ OH-16

235 1 138 95 1 92U + 0n → 53I + 39Y + 3 0n + γ OH-17

235 1 144 89 1 92U + 0n → 56Ba + 36Kr + 3 0n + γ OH-18 HPT001.009B Revision 3 Page 8 of 42

e. The fission fragments and their decay products are called OH-19 fission products.

1) There are ~250 different isotopes known as fission products which could result from the fission process.

2) Examples of the fission process with the resultant fission fragments and the fission fragments decay with resultant fission products are:

235 1 135 97 1 92U + 0n -> 52Te* + 40Zr** + 4 0n + γ OH-20

135 135 135 135 135 * 52Te -> 53I + β + γ -> 54Xe + β + γ -> 55Cs + β + γ -> 56Ba + β

97 97 97 ** 40Zr -> 41Nb + β + γ -> 42Mo + β + γ

f. About 1 in 10,000 fissions produce a ternary fission event. Obj. B5 Ternary fission results in three fission fragments, one of which is tritium (3H).

g. The neutrons provide:

1) the continuation of the bombardment of 235U, creating a chain reaction, thus producing more fission fragments.

2) neutron capture in the structural components and other material of the plant resulting in these materials becoming radioactive creating activation products.

3) neutron capture in the uranium fuel resulting in the Note – U238 production of transuranic elements as activation products. captures a neutron and activates to U239, a transuranic element

2. The 235U Fuel pellets are contained in a long tube called a fuel rod. Obj. B6 OH-21

a. This fuel rod is made of thin metal sheath material called cladding.

1) The function of the cladding is to:

a) provide mechanical support.

b) facilitate uniform heat transfer from the fuel to the coolant. HPT001.009B Revision 3 Page 9 of 42

c) protect the fuel from the corrosive action of the coolant.

d) contain the fission fragments, transuranic elements and activation products created in the rods.

B. Sources of radiation from a nuclear reactor are separated into two types which are radiation at the core and radiation from the coolant.

1. The design of a nuclear power plant provides a source of radiation at the reactor core.

a. The radiation from the core includes: Obj. B7 OH-22 1) gamma rays emitted during the fission process inside the fuel rods.

2) neutrons emitted during the fission process inside the fuel rods.

3) gamma rays emitted from fission fragment decay inside the fuel rods.

4) gamma rays emitted during neutron capture creating activation products inside the core structure and shield.

5) gamma rays emitted during the activation product decay process.

b. A sizable inventory of fission products accumulate in the reactor fuel during burn-up, creating an enormous source of radioactivity and radiation exposure.

c. Radionuclides present, as contaminants in the reactor coolant, Obj. B8 are sources of radiation from the coolant. OH-23

d. The fission product radionuclide contaminants in the reactor coolant are a result of the release of fission products created inside the fuel rod to the coolant. HPT001.009B Revision 3 Page 10 of 42

1) Fission products are released by: OH-24

a) the creation of pinhole to large cracks in the thin cladding due to:

(i) thermal stresses. (ii) mechanical forces. (iii) internal gas pressures. (iv) corrosive action by the coolant.

b) penetration through the pores of the cladding.

2) The rate of release is determined by:

a) fuel temperature.

b) pressure and concentration gradients across the cladding.

c) chemical nature of each individual fission product.

d) size of the cracks in the cladding.

3) Additionally, the fission product radionuclide contaminants OH-25 in the reactor coolant are also a result of:

a) tramp uranium dust, on the outside of the fuel rod surface, allowing the fission process to occur outside the fuel bundle, thus releasing fission products into the reactor coolant.

b) trace uranium impurities, in the fuel rod cladding material, allowing the fission process to occur outside the fuel bundle, thus releasing fission products into the reactor coolant. e. The activation product radionuclide contaminants in the Obj. B11 reactor coolant are a result of:

1) neutron activation of corrosion and wear products of structural materials of the reactor coolant loop. HPT001.009B Revision 3 Page 11 of 42

a) The reactor coolant loop structure material products OH-26 are:

(1) stainless steel (2) zicaloy (3) inconel (4) carbon steel (5) other steel and copper alloys such as nickel, (6) chromium and cobalt (stellite).

b) Structural material activation products provide the largest source of radiation exposure.

2) neutron activation of coolant/steam and impurities or OH-27 chemical additions.

3) transuranic elements from:

a) neutron activation of tramp uranium products on the outside of the fuel rod cladding.

b) neutron activation of released transuranics from cladding failure of the failed fuels.

C. Fission Products

1. Fission Products are important because: Obj. B9 OH-28 a. They influence the availability of oxygen

b. Their volume is different

c. Fission gases escape increasing pressure in the fuel

d. Solid fission products can change the thermal conductivity and melting point

e. Gaseous fission products can change the thermal conductivity

f. The chemical and physical changes of fission products produced affect the magnitude of the radiation exposure source. HPT001.009B Revision 3 Page 12 of 42

1) Chemical and physical changes:

a) In a physical change, the substances are not altered chemically, but merely changed to another phase (i.e., gases, liquid, solid) or separated or combined.

b) In a chemical change, the substances are altered chemically and display different physical and chemical properties after the change.

2. There are three types of fission products produced during the Obj. B10 fission process: OH-29

 Halogens  Noble gases  Particulates

a. Halogens – Iodine

1) Iodine is a halogen which is most produced from fission.

2) Iodine is produced in the fuel gap as an aerosol and disperses throughout the fuel gap. A fuel cladding defect will release the iodine into the coolant.

3) Elemental iodine is a non-metallic volatile crystalline solid. Iodine can go directly from a solid to a gas (vapor).

4) Iodine is present in the fuel in many forms. The pH chemistry in the coolant controls the percentage of each form of iodine present.

5) There are 30 isotopes of Iodine and only one is stable (I-127).

a) Some other the iodine isotopes produced by nuclear fission are I-129, I-130, I-131, I-132, I-133, I-134 and I-135.

b) I-131 is the iodine isotope of primary concern produced in fission. It has a half-life of 8.05 days. I-131 can be used to detect recently released fission products. HPT001.009B Revision 3 Page 13 of 42 b. Noble gases

1) Noble gases are produced in the fuel gap, and due to their volatility, will disperse throughout the fuel gap.

2) Because of their insolubility and gaseous nature the fission gases tend to promote volume changes in the fuel or they tend to change gas pressure in the fuel pin. Being gases they form bubbles and build up pressure on the thin cladding.

3) With a cladding leak the noble gases diffuse out of the fuel gap into the primary reactor coolant quickly.

4) The majority of the fission noble gaseous radionuclides have fairly short-lived half lives.

5) Examples of fission noble gas isotopes are Kr-85m, Kr-85, Kr-88, Xe-131m, Xe-133m, Xe-133, Xe-135m, Xe-135, Xe-138.

6) In PWR’s a percentage of the primary coolant is bled off and degassed by the waste gas decay system.

7) In BWR’s the primary coolant is used to turn the turbines, thus fission gases are present on the secondary side.

a) An important feature is the air ejector system which passes the steam through a series of nozzles to create a vacuum which removes air from the condenser.

b) In addition, a gland seal system is used to seal the main turbine by passing high pressure steam over a series of ridges.

c) The steam-air ejector and gland seal systems give rise to gases, with a high proportion of fission noble gases, which must be vented from the site HPT001.009B Revision 3 Page 14 of 42

8) After a reactor shutdown it cannot be started up again immediately.

a) This is because of Xe-135 (half-life – 9.1 hrs), a daughter product of fission fragment Te-135.

b) Xe-135 has an extremely large cross section for the capture of slow neutrons, thus it is necessary to wait for it to decay to a sufficiently low level before the reactor can go critical again.

c. Particulates

1) Particulate chemical states are based upon the nuclide. Although they are soluble to a degree based upon their chemical state, they can be volatile if in aerosol form (Cs, Rb, Te). They can be metallic (Sb, Sn, In, Cd, Ag, Pd, Rh, Ru, Tc, Mo, Te) or form oxides (Nb, Mo, Zr, Sr, Ba, Cs, Rb, Te) or solids (Ce, Pr, Nd, Pm, Sm, Eu, Y, La, Zr, Sr, Ba, Te).

2) Examples of particulate radionuclides are Cs-138, Ba-140, La-140, Sr-90, Mo-99.

3) Examples of particulate isotopes with half-lives greater than 2 months are Zr-95 (65 d), Ru-106 (1 yr), Ce-144 (268 d), Pm-147 (2.6 y), Cs-134 (2.1 y), Sr-90 (28.8 y), Cs-137 (30.2 y).

4) Particulate fission products diffuse from a fuel rod cladding leak into the primary reactor coolant relatively slowly.

5) Particulate fission products in the reactor coolant are removed when part of the coolant is cycled continuously through a demineralizer column that removes the dissolved activity by ion exchange.

6) Cs-138 is of primary concern because it is not effectively Review Appendix 2 removed by ion exchange. OE – Fuel Defect Operation OH-30 OH-31

D. Activation Products Obj. B12 OH-32 1. An activation product is a stable nuclei which has become radioactive as a result of neutron activation. HPT001.009B Revision 3 Page 15 of 42

2. The types of activation products are activated corrosion products and activation of water, impurities and chemicals in the water.

3. Activated corrosion products are produced by neutron capture in OH-33 structural materials.

4. All metallic surfaces corrode.

5. Reactor coolant is pure by normal standards but there are impurities resulting from the corrosion or erosion of the core and structural materials in the coolant system.

a. Metals in water cooled reactors are iron, nickel, cobalt, and manganese due to corrosion of the coolant system.

b. In addition, zirconium from the cladding material, copper from the condenser system, silicon and organic materials from the water purification systems are in the water from corrosion.

c. Corrosion gradually results in a build-up of activation product nuclides such as Cr-51, Mn-54, Mn-56, Fe-55, Fe-59, Co-58, Co-60, Zn-65, Ni-63.

d. The dominating corrosion products 51Cr, 54Mn, 59Fe, 58Co, 60Co, 65Zn, 124Sb create significant radiation dose. Co-60 (5.2y) and Fe-59 (454d) account for most personnel dose.

e. The longer lived species (Fe-55, Ni-63, Co-60) are of more concern with the problems in radioactive waste handling and disposal.

f. The corrosion rate of alloys rich in nickel, chromium and OH-34 stainless steel (18Cr8Ni) leads to the release of Fe, Cr, Co, and Ni.

1) stainless steel and Inconel produce Co-58 from Ni-58 2) iron in steel produces 59Fe from 58Fe 3) satellite in flow valves produces 60Co from 59Co 4) all types of steel contain Co-59 to produce Co-60

Ni-58(n,p)Co-58 (decays gamma 70 d)

59Co(n, γ)60Co (decays beta, 2 Gamma - 5.22 yr)

58 1 59 Fe + 0n → Fe (59Fe-> 59Co + β + γ) HPT001.009B Revision 3 Page 16 of 42 g. Corrosion products in reactor water are either insoluble or OH-35 soluble and are transported by water to all parts of the primary system. h. Under normal operating conditions, among common activated corrosion products, only Fe-55 and Fe-59 are truly insoluble. i. The corrosion products form insoluble products referred to as Obj. B13 “crud”. OH-36

1) Deposition of crud on the fuel elements surfaces may block cooling canals, and because of its poor thermal conductivity may lead to burn-through of the cladding.

2) In a BWR the “crud” deposits are generally found heaviest OH-37 ~50-100 cm from the bottom of the fuel rod where boiling starts.

3) In a PWR the “crud” can be quite mobile and the major OH-38 factors affecting crud transport (deposition/dissolution) are the coolant pH and the hydrogen concentration. j. In the primary system “crud” transport is a continuous process from one surface to another via the coolant.

1) In a PWR the crud is transported through the whole primary cooling circuit, but removed in the purification circuit.

2) In a BWR the crud accumulates in the reactor vessel, therefore BWR’s have a special cleaning circuit attached to the vessel.

3) 58Co in Inconel piping has been found to be the principal “crud” activity in PWR’s.

4) 59Co found in stellite in flow valves produces 60Co which represents the chef ‘crud’ activity in BWR’s. k. The “crud” carried with the cooling loop creates a serious OH-39 radiation problem. l. Proper control of chemistry and removal of corrosion products can minimize these radiation levels.

1) Proper pH control helps minimize corrosion products. HPT001.009B Revision 3 Page 17 of 42

2) Use of corrosion inhibitors can minimize this corrosion.

3) The amount of crud insoluble activities deposited in the reactor can be partly removed during shut down by mechanical cleaning or washing with chemical decontamination solutions.

4) Filtrate soluble activities will appear ultimately in the radwaste treatment system, some in soluble form and some in particulates.

m. Considerable effort is put into the development and selection of Review Appendix 3 corrosion-resistant materials. OE – Crud Burst During Station Outages OH-40 OH-41

6. Activated coolant products are produced by activation of water, air, impurities or chemicals in the coolant.

a. Activation of water Obj. B14 OH-42 The intense flux of fast and thermal neutrons induces several radioactivities in H2O.

Initial Isotope Reaction Yields T 1/2 2H (n, γ) 3H 12.3 yrs 16O (n,p) 16N 7.13 sec 16O (n,p) 17N 4.14 sec 18O (n, γ) 19O 26.8 sec 18O (n,p) 18F 109.8 min 16O (p,α) 13N 9.9 min 14N (n,2n) 13N 9.9 min

b. An important reaction on the oxygen component of the coolant OH-43 is 16O (n,p) 16N

1) The N-16 isotope emits a high energy gamma upon decay and is the major source of activity during operation.

16 16 7N → 8C + β + γ

2) Upon shutdown the N-16 activity level very quickly drops off because of the short 7.2 sec half-life HPT001.009B Revision 3 Page 18 of 42

3) N-16 emits very penetrating gamma rays thus it has great influence on the shielding requirement.

4) In a PWR it is confined to the reactor water, but in a BWR it travels with the steam to the turbine building creating high radiation levels.

c. Another reaction with the oxygen component is the production Note – N-13 also of N-13. produce from nitrogen impurity in 16O(p,α)13N system 14N(n,2n)13N 1) In BWRs N-13 contributions to the radiation levels are masked by N-16 and in PWRs N-13 provides minimal OH-44 significance.

2) The decay scheme for N-13 is: 13 13 + 7N → 6C + β

3) In a BWR the 9.9 min half-life of N-13 is long enough to allow some discharge to the environment.

d. F-18 is also produced from the oxygen component in water. OH-45

18O(n,p)18F

1) The 110 min half-life decay scheme for F-18 is: 18 18 + 9F → 8O + β

2) F-18 is very soluble in water and is the major contributor to the liquid activity of PWRs.

3) In a BWR it is the major feedwater activity.

7. Activation of impurity – air Obj. B15 OH-46 a. Air is present as an impurity in the coolant of water cooled Note – Oxygen in air reactors. molecule interact same as in water molecules

b. Air contains about 1% of the inert gas argon and the neutron activation product formed is Ar-41 with short half-life of 1.38 hrs.

40Ar(n, γ)41Ar HPT001.009B Revision 3 Page 19 of 42

41 41 The decay scheme for Ar41 is 18Ar → 19K + β + γ

c. Ar-40 is naturally occurring and there are small quantities in makeup reactor water. When deaerated make-up water is used, the Ar-40 activity is usually quite low.

d. If a high Ar-41 activity level does occur it is usually due to an introduction of air into the reactor coolant system.

8. Activation of impurities OH-47

a. Some S-35 is also formed from the S-34 and Cl-35 impurities.

b. C-14, a long-lived 2730 years half-life neutron activation nuclide, arises in all types of reactors.

c. Variable amounts of 14C are also produced, from both 13C and from 14N, another impurity.

d. Some 14C also arises from ternary fissions.

9. Activation of chemicals Obj. B16 Note–BSL-WBNP a. A radionuclide of considerable importance which is produced RCI-137 Radcon in all reactor systems is tritium (H-3). Tritium Control Program

1) Tritium is produced OH-48

 by fission  by a neutron activation (n, γ) reaction on water deuterium(2H)  by various reactions on lithium and boron.

b. Lithium and boron are present in most systems either as Obj. B17 additives, neutron absorbers, or impurities and can contribute OH-49 to tritium production by a number of reactions.

1) In PWRs, boric acid is used as the ‘chemical shim’; a burnable poison used for obtaining better distribution in the core and as a convenient means for fine controlling the reactor power level.

2) In PWRs lithium is injected for pH control. Li is also produced by B-10 neutron activation. HPT001.009B Revision 3 Page 20 of 42

3) Boron activation

Tritium production

10 1 7 3 5B + 0n(f) → 3Li* + α → 1H + α *excited state

Lithium production

10 1 7 5B + 0n(th) → 3Li + α

4) Lithium activation

Li-6 may undergo a 6LI(n, α)t reaction.

6 1 3 3Li+ 0n → 1H + α

This reaction does not have a neutron energy threshold and thus occurs with very low or high-energy neutrons.

Li-7 reaction

7 1 3 1 3Li + 0n(f) → 1H + α + 0n

c. Tritium has a half-life of 12.3 yrs and decays by low energy OH-50 beta emission only and is difficult to detect.

d. Tritium generated by these processes in contact with water or water vapor quickly becomes an integral part of the coolant water.

e. Thus when tritium combines with water (or is formed in the coolant) it becomes difficult to separate.

f. Since condenser water is currently discharged to the environment, tritium goes into the environment with it.

g. Tritium accounts for more activity in reactor plant effluents than any other source.

E. The sources of radiation in the reactor coolant from the fission process, Obj. B18 fission products, and activation products, create exposure potential OH-51 throughout the plant.

1. Exposure potential to personnel is greater near the core and reactor coolant piping and component areas when the reactor is operational. HPT001.009B Revision 3 Page 21 of 42

a. Higher exposure potential is due to the gamma and neutron radiation emitted during the fission process and gamma emitted during fission and activation products decay.

b. Entry is limited to these areas due to the higher exposure potential.

c. In a BWR, steam from primary reactor coolant is used to create mechanical energy in the turbines. Areas in the turbine building containing main steam piping and components also have limited access due to the gamma emitted by activation and fission products present.

2. Exposure potential to personnel decreases in these areas when the OH-52 reactor is shut down.

a. Neutron and gamma radiation is no longer produced by the fission process.

b. Fission and products activation are no longer produced.

c. Many of the existing fission and activation products have short half-lives thus the exposure potential from them decreases.

d. During shutdown the radiation sources are long-lived gamma emitting fission and activation products present in the coolant, piping and components.

3. Radiation sources exist throughout the plant from components and Obj. B19 piping which have received part of the reactor coolant for reactor OH-53 water control, safety design, process control, or system clean-up.

a. Areas containing these system’s piping and components have exposure potential for personnel entering due to the gamma emitting fission and activation products in the coolant.

b. The clean-up system is designed to remove the fission and activation products, thus the filters and ion exchanger media utilized and the associated piping and components will provide a high exposure potential.

c. Radioactive material emits radiation. Disposable radioactive material is called radioactive waste or radwaste.

1) Radwaste items and the processing of radwaste have high exposure potential. HPT001.009B Revision 3 Page 22 of 42

2) System clean-up devices such as filters and ion exchange media are examples of radwaste items with high exposure potential.

d. Fission and activation products as they flow through the piping Obj. B20 and components can deposit in low flow areas causing the OH-54 build-up of radiation levels in these low flow areas.

1) These areas of build-up are called ‘Hot Spots’ and provide Note–BSL-BFN a high exposure potential. RCI-23 Hot Spot Tracking Program

2) Examples of ‘Hot Spot” potential areas are:

 Piping bends  Piping reducers  Piping welds or joints  Valves

e. The coolant circuit of the reactor and its associated systems are significant sources of gamma radiation and in some cases must be shielded.

F. There are sources of radiation produced outside the nuclear plant and Obj. B21 brought into the plant environment in support of plant production. OH-55

1. Radioactive material produced outside the plant and brought into Note–BSL- its environment are divided into 3 categories: Corporate SSP 5.1 –  Radioactive sources Radiological  X-ray devices Controls  Radioactive material shipment receipt SSP 5.6 – Controlling Byproduct and Source Material SSP 5.8 – Special Nuclear Material Control HPT001.009B Revision 3 Page 23 of 42 a. A Radioactive source is any By-product or source material Note–BSL-BFNP with known isotopes and activity manufactured for the purpose RCI-7 Receipt of of measuring, checking, calibrating, or controlling processes Radioactive quantitatively or qualitatively. Materials

Note–BSL-SQNP RCI-06 Receipt of Radioactive Materials b. There are 3 classifications of radioactive sources: OH-56

 Special nuclear material (SNM) Note–BSL-SQNP  By-product material RCI-17 Control of  Radiography sources Byproduct and Source Material c. Special Nuclear Material is Plutonium, Uranium-233, uranium Def.- Source enriched in the isotope 233, or in the isotope 235, and any other material- material which the NRC, pursuant to the provisions of Section Uranium or thorium, 51 of the Atomic Energy Act of 1954, determines to be SNM or any combination or any material artificially enriched by any of the foregoing; thereof, in any but does not include source material. physical or chemical form, or ores that contain by weight one-twentieth of one percent (0.05%) or more of uranium, thorium, or any combination thereof.

1) It will be placed on an inventory sheet and placed under Source material does control of Special Nuclear Material Custodian. Inventory not include SNM. to be routinely performed. Note–BSL-WBNP RCI-103 Radioactive

2) It will be surveyed upon receipt. Material Control

3) Exposure potential is based upon isotope and content. d. By-product source material is any material (except SNM) Note–BSL-SQNP yielded in, or made radioactive by, exposure to the radiation 0-SI-RCI-000-056.0 incident to the process or producing or utilizing SNM. Byproduct Material Inventory and Sealed Source Leak Test HPT001.009B Revision 3 Page 24 of 42

1) It will be surveyed upon receipt and routinely thereafter. Note–BSL-WBNP RCI-127 Byproduct and Source Material Control

2) It will be placed on inventory sheet and placed under control of By-product Material Custodian. Inventory to be routinely performed.

3) Exposure potential is based upon isotope and content. e. Radiography is the examination of the structure of materials by Review Appendix 4 nondestructive methods utilizing sources of radiation. OE – Radiography OH-57 OH-58 OH-59 OH-60

1) Ionizing radiation produces radiographic images, either Note–BSL-BFN analog or digital. Byproduct materials emit gamma RCI-20 radiation (Co-60, Cs-137, Ir-192). Radiographic Operations- Control and Monitoring

2) Electronic equipment electronically generates x-rays. Note–BSL-SQNP RCI-16 Radiation Protection During Radiographic 3) Will be surveyed upon receipt. Operations

4) Strict requirements for utilization and continuous Radcon Note–BSL-WBNP coverage. RCI-129 Radiographic Operations

5) Radioactivity level of source provides high potential for exposure. f. X-ray devices are utilized at a plant for processes such as OH-61 Protected Area entry security searches of items.

1) Routine surveys required to ensure no leakage from designed shielding devices.

2) Exposure potential with design structure change or incorrect performance of operational procedures. HPT001.009B Revision 3 Page 25 of 42

g. Radioactive material shipment receipts are required for all radioactive material received on site. We have discussed sources, but other items may be required to be received.

1) All items require a survey upon receipt.

2) Exposure potential with opening unknown items.

G. The fission and activation products in the reactor coolant are potential Obj. B22 sources of contamination throughout the plant. OH-62

1. Contamination is radioactive material in an unwanted place.

2. When reactor coolant, coolant gases, fission products, or activation products which are inside the reactor coolant system and support systems piping and components, escape from the piping or component, they create contamination.

3. Contamination escapes the piping or components when: Note – Discuss the potential exposure a. it is opened (breached) for maintenance from beta radiation with system breach, b. reactor coolant spills occur from: spill, or leaks due to the removal of c. Reactor coolant leaks occur from: piping/component shielding. 1) valves

2) flanged connections in manways, closures, pipe caps

3) defective pump gaskets

4) defective welds

5) boric acid corrosion through piping

4. Contamination can be loose, fixed or airborne. Obj. B24 OH-63

a. Loose contamination is transferable or smearable. Note-BSL-WBNP RCI-102 Contamination and Hot Particle Control HPT001.009B Revision 3 Page 26 of 42 b. A special type of loose contamination which has high exposure Obj. B23 potential is “Hot Particles”. OH-64 Note–BSL-BFN RCI 15.1 Maintaining

1) A “Hot Particle” is a single discrete object (particle) Occupational generally difficult to see with the naked eye, and at least 0.1 Radiation Exposures microcuries of radioactivity. As Low As Reasonably Achievable (ALARA)

2) It is either an activated corrosion product (normally stellite) Review Appendix 5 or a fuel fragment with high specific activity. OE – Hot Particle Work Area OH-65 OH-66 c. Precautions are necessary to ensure loose contamination is not OH-67 transferred onto or into the body. OH-68 OH-69 OH-70

1) Transfer of loose contamination onto the body is a potential OH-71 exposure to the emitted radiation both as gamma radiation and skin dose exposure from beta radiation emitted. Exposure potential depends on the particulate isotope and radioactivity of the radioactive material (contamination) transferred onto the body.

2) Transfer of loose contamination into the body is a potential exposure to the emitted gamma radiation, beta radiation, and/or alpha radiation. Exposure potential depends on the particulate isotope and radioactivity of the radioactive material (contamination) transferred into the body.

3) Loose contamination can become fixed contamination if it becomes embedded in an item.

4) Loose contamination can become airborne contamination when there is sufficient movement to cause entry into the air. HPT001.009B Revision 3 Page 27 of 42 d. Fixed contamination is non-transferable or cannot be readily OH-72 removed.

1) Exposure potential depends on the isotope and radioactivity of the contamination imbedded in the item.

2) Fixed contamination can become loose or airborne with degradation of the item structure by welding, grinding, sanding, cutting or other abrasive activities e. Airborne contamination is the release of radioactive material OH-73 into the air in the form of gas, vapor or particulates.

1) The release of noble gases occurs with an opening in the closed coolant circuit or associated circuits containing noble OH-74 gas fission or activation products.

a) Noble gases being inert will disperse evenly throughout the atmosphere.

b) Noble gases emit beta radiation.

c) The potential exposure to the skin when submerged in noble gas is higher than the potential exposure to the lung with intake. Thus, airborne noble gas is considered a potential external skin exposure.

d) Pollutant noble gases can be removed by decay through the waste gas system.

e) The release of vapors can occur with an opening in the Note–BSL-SQNP closed coolant circuit or associated circuits containing RCI-20 Radioiodine iodine fission products. Monitoring during Accident Conditions

Exposure potential is dependent on the iodine isotope, OH-75 iodine form, and radioactivity of the iodine vapor in the air transferred into the body.

f) Entry into the body is through inhalation and ingestion.

(1) When Iodine enters the body, it travels from the lung through the blood stream to the thyroid. Thus, the critical organ for Iodine isotopes is the thyroid. HPT001.009B Revision 3 Page 28 of 42

(2) Pollutant iodine vapors can be removed by OH-76 absorbent, usually activated, charcoals.

(a) Elemental iodine is removed very effectively by activated charcoal.

(b) Organic iodine is not bound as well on charcoal and loses effectiveness at high humidity.

(c) The charcoal must be impregnated with a chemical with which the organic iodine will combine; usually potassium iodide (KI) or triethylenediamine (TEDA).

(d) TEDA reacts with iodine converting the radioiodine molecule. This is effective with air streams of high moisture content.

2) The release of particulates occurs with an opening in the OH-77 closed coolant circuit or associated circuits containing particulate fission or activation products.

a) The particles can become airborne with:

(1) Release of fission or activation particulates in aerosol form

(2) movement of loose contamination particulates in solid form

(3) degradation of fixed contamination particulates in solid form

b) Transfer of airborne contamination onto the body is a potential exposure to the emitted radiation both as gamma radiation and skin dose exposure from beta radiation emitted. Exposure potential is depended on the particulate isotope and radioactivity of the radioactive material (contamination) transferred onto the body.

c) Transfer of airborne contamination into the body is a potential exposure to the emitted gamma radiation, beta radiation, and/or alpha radiation. Exposure potential is depended on the particulate isotope and radioactivity of the radioactive material (contamination) transferred into the body. HPT001.009B Revision 3 Page 29 of 42

d) Airborne particulate contamination can become loose contamination with plate-out. Airborne particulate contamination can become fixed contamination if embedded into an item.

e) Pollutant particulates can be removed by a filtration OH-78 system. Review Appendix 6 OE – Radioactive Filter Handling OH-79 OH-80 OH-81 OH-82

H. Dose is received from exposure to sources of radiation and Obj. B25 contamination.

1. Individual occupational dose from exposure received from sources Use Appendix1 of radiation and contamination is restricted by regulations. to review 2002 data

a. Individual workers are trained to ensure they maintain their dose as low as reasonably achievable.

b. Radcon provides support necessary to help workers maintain this requirement.

2. Collective dose of all individuals from exposure received from OH-83 occupational sources of radiation and contamination is to be limited by the plant per regulations.

a. The plant provides procedures and work instructions to limit collective dose.

b. The plant also provides source term reduction plans to limit the sources of radiation and contamination in the plant thus limiting the collective dose. HPT001.009B Revision 3 Page 30 of 42

XI. SUMMARY:

You now understand the sources of radiation and contamination for occupational exposure. As a Radcon Technician, your identification of fission and activation products, their radioactivity, and the hazards associated with each will allow you to maintain your individual dose as low as reasonably achievable and provide guidance for other workers to maintain their individual dose ALARA, thus limiting the collective dose received by all workers at the nuclear power plant. HPT001.009B Revision 3 Page 31 of 42 Appendix 1

2002 Dose Totals for TVAN Power Plants

Calendar Number Number of Number of Collective Average Average year of Monitored workers TEDE TEDE Measurable licensees Individuals with (person- (rem) TEDE per reporting Measurable rem) Worker TEDE (rem)

2002 104 107,900 54,460 12,126 0.11 0.22

2002 BFNP 1,977 358/reactor 0.18 2002 SQNP 1,257 108/reactor 0.09 2002 WBNP 909 94/reactor 0.10

3 year total- average BFNP 5,159 109/reactor 0.19 985/site SQNP 4,588 102/reactor 0.13 611/site WBNP 2,159 74/reactor 0.10 222/site HPT001.009B Revision 3 Page 32 of 42 Appendix 2 Just-In-Time Operating Experience

Fuel Defect Operation, Revision 1 Operating limits, increased reactor coolant sampling, and additional radiation surveys have been necessary while operating with fuel defects. Events Plant: Braidwood Units 1 and 2 (PWR) Defective Fuel Indications -- Reference: OE 16208, OE16565, OE 16575 In May and July 2003, Braidwood Station detected indications of fuel cladding defects in both units. Unit 1 began experiencing increased coolant activity in early May, shortly after completing a refueling outage. Unit 2, which is scheduled to begin refueling in October 2003, experienced indications of a fuel defect after a 30 percent power ramp that occurred in June 2003. Important Points:  A reactivity maneuver restriction was imposed, limiting power changes to 3 percent per hour between 80 and 100 percent power.  Chemistry verified that increased coolant Xenon activity was not caused by cross- contamination between units.  Letdown purification flow was raised and additional sampling for fission product trends was started. Plant: Diablo Canyon Unit 2 (PWR) Primary Hydriding of Fuel Assembly Cladding -- Reference: OE 15703 On February 15, 2003, Diablo Canyon reported indications of cladding leakage in Vantage 5 fuel attributed to primary hydriding. The simultaneous increase in Xenon 133 and Iodine 131 activity provided a typical signature of cladding defects in low exposure fuel. Important Points:  A second Xenon/Iodine spike occurred 72 days into the operating cycle.  A significant increase in Iodine 131 occurred 400 days into the cycle, indicating that the cladding crack had opened up. Plant: River Bend (BWR) Fuel Clad Penetration -- Reference: OE15390 On December 2, 2002, River Bend experienced at least one fuel rod clad penetration approximately 13 months into the fuel cycle. Power suppression testing revealed that two symmetric fuel assemblies could be leaking. Important Points:  Off gas activity increased from 2 micro curies per second to 480 micro curies per second and peaked at 1,000 micro curies.  Reactor coolant Iodine levels increased by more than a factor of 10. Plant: Crystal River Unit 2 (PWR) Fuel Inspection Results -- Reference: OE14665 On September 26, 2002, Crystal River reported that recent fuel examinations showed that spacer grid fretting was the predominate cause of cladding defects, with fuel rod end cap weld failure as the second leading cause. Important Points:  End cap weld failure can result in hydriding and cladding perforation. Plant: Hope Creek (BWR) Fuel Defect Causes Interim Power Reduction -- Reference: OE13551 On March 4, 2002, Hope Creek reduced power to 90 percent when the off gas radiation monitor alarmed and subsequent grab samples indicated that activity had increased to 3,800 micro curies per second. Important Points:  Chemistry samples confirmed that a fuel defect was present.  The station increased sampling of the off gas releases. HPT001.009B Revision 3 Page 33 of 42  Conservative limits were placed on power ramp rates to mitigate additional cladding damage.  A control rod was fully inserted to suppress local power around the suspected fuel rod.

Important Considerations when operating With Fuel Defects (Lessons Learned)  How will the fission products affect reactor water demineralizers? What effect does this have on the conduct of operations, chemistry, and radiological practices? What path will the resin travel when the demineralizer is being regenerated? How will we monitor the gaseous release from the resin?  How have we applied lessons learned from previous operation with fuel defects? What lessons are specific to our operating condition?  What chemistry changes should we expect because of the defective fuel? How have we determined sample rates? What are the radiological consequences of the increased sampling? What plans do we have to respond to a coolant sample spill?  What operating and chemistry limits have we established to minimize the likelihood of aggravating our fuel defects? What actions can we take now to prevent additional fuel defects? What site and corporate engineering recommendations have been incorporated into these actions?  What are our administrative controls for operation with fuel defects? Are the controls consistent with industry guidelines? What do industry guidelines recommend?  What is the effect due to fuel defects on the limits for release rate to the public? What procedures provide guidance for controlling releases?  What is the known leakage from the primary system to the secondary systems and auxiliary buildings? How have we modified the administrative leakage limits based on the known fuel defects?  How have we analyzed the effect of control rod surveillance testing on reactor coolant activity levels? What changes have been made as a result of this analysis?  When are radiation monitor efficiency factors adjusted to compensate for the different energy level present in fission beta particles? Who is responsible for setting the time and frequency of these adjustments? What type of support is needed to allow these adjustments?  What is the projected change in coolant activity levels? How long can we expect to operate before reaching the administrative limit for coolant activity/off-gas release rate? What are our pre-established limits, and how are we measuring them?  What is the most likely area of the core affected by the fuel defects? For BWRs, how will flux suppression testing affect the condition of the fuel? Should any sudden changes in radioactivity be anticipated? What radioactivity changes would cause us to stop the flux suppression testing?  What recent training have operators had on the simulator that replicates plant transients with fuel defects? Did the training address the current situations and anticipated plant responses?  What contingency plans have we made for a technical specification required shutdown caused by increasing primary coolant activity levels? For a controlled shutdown, how will activity levels increase the time required to reach cold shutdown?  What are the expected coolant activity responses following a plant trip? How will this affect our response?  What precautions have we implemented to detect hot particles? Where would hot particles appear, and how soon after detection of the fuel failure?  What plans do we have for communicating changing radiological conditions in normally clean areas? What special equipment will we need for access to normally clean areas? How have we communicated this need to other departments to ensure adequate resource availability?  Who is responsible for updating current maintenance planning to allow for fuel defects and power change limitations? How will we modify the forced and refuel outage planning to make allowance for increased exposure and contamination levels? Who is responsible for doing this? HPT001.009B Revision 3 Page 34 of 42 Appendix 3

Just-In-Time Operating Experience

Crud Bursts During Station Outages

Crud bursts have resulted in high radiation levels and other complications affecting operations and maintenance activities during station outages.

Events Plant: Byron 2 High Radiation Level During Refueling Cavity Flood-up -- Reference: OE9215 On April 16, 1998, a containment isolation signal actuated on high radiation levels as the refueling cavity was being filled following removal of the reactor vessel head. Radiation levels at the surface of the refueling cavity reached 650 millirem/hr, and 250 millirem/hr at the cavity railing. The area radiation monitors read as high as 60 millirem/hr. The high level of Cobalt 58 present in the reactor coolant system caused the unexpected radiation levels.

Important Points:  A crud burst was in progress at the time the vessel head was removed because hydrogen peroxide addition was delayed for two hours.  Letdown flow was maintained at too low a value to effectively clean up the reactor coolant system before the head lift began. Contributors:  Operations personnel were not responsive to Chemistry requests to increase letdown flow rate.  Chemistry procedures did not incorporate EPRI guidance on the concentration of soluble Cobalt 58 that would have minimized radiological hazards. Plant: Perry Crud Burst in Refueling Cavity Caused by Recirculation Pump Testing -- References: OE10097 On April 27, 1999, dose rates in the refueling cavity increased by a factor of 10 when crud was flushed from fuel assembly surfaces during post maintenance testing of the recirculation pumps. Dose rates at the cavity surface rose to 60 millirem/hr. Corrosion products were flushed from fuel surfaces by the high flow rates produced by the recirculation pumps.

Important Point:  The recirculation pumps were tested with their discharge valves fully open. Contributors:  Station personnel did not recognize the radiological implications of starting the recirculation pumps.  There were no restrictions on the number of recirculation pumps that could be started at the same time. HPT001.009B Revision 3 Page 35 of 42 Plant: Catawba 2 Crud Burst Causes Oscillations in Intermediate Range Detector -- Reference: OE10553 On May 4, 1999, the unit experienced a full load rejection and entered hot shutdown conditions on May 5. While making preparations for startup on May 13, technicians could not adjust the compensating voltage on ex-core intermediate range channel N36. Both intermediate range channels also were observed to oscillate. Subsequent problems with the main generator resulted in the unit remaining at hot shutdown conditions for the next 30 days, and the intermediate range oscillations continued throughout the shutdown period. The oscillations were attributed to high background gamma radiation caused by crud in the reactor.

Important Point:  The crud in solution following the shutdown plated out in the reactor coolant system because of the prolonged time the reactor coolant system was maintained at 340 degrees Fahrenheit. Contributors:  The intermediate range compensating voltage should have been adjusted within 20 to 60 minutes following shutdown.  Upper and lower limits on source range count rate were not established to ensure the intermediate range detectors were adjusted during periods of low gamma radiation levels.

Important Considerations Associated with Crud Bursts (Lessons Learned)  Who reviewed the outage schedule to identify activities with the potential to cause crud bursts? How will we control these evolutions?  Who has verified that sufficient chemistry and health physics personnel are available to support activities that have a high probability of initiating a crud burst? How have we verified that there is adequate supervisory oversight for these activities?  How will we adjust RCS chemistry control when outage activities result in frequent changes in RCS temperature? How was RCS chemistry control factored into the outage scope and emergent work activities?  How will we ensure that adequate time is available to remove RCS contaminates after using chemical injection to initiate a crud burst?  How have we verified that letdown ion exchangers have adequate capacity to remove contaminates resulting from a crud burst? At what point will we change out letdown filters? What is the optimum letdown flow rate for cleanup? How will we verify that the correct flow rate is maintained?  What controls are in place to prevent flooding the refueling cavity when high levels of radioactive contaminants (Cobalt 58, for example) are present in the RCS?  How will we minimize radiation exposures caused by crud bursts while testing reactor coolant pumps, recirculation pumps, and emergency core cooling pumps?  What chemistry controls have we implemented for mid-cycle outages to minimize crud bursts? How will we minimize crud plate-out during those periods when the RCS is not at cold shutdown conditions?  How will we verify that excore nuclear detectors, such as the intermediate range channels, will be calibrated and adjusted when gamma background radiation is not excessive? How will we use the source range instruments to provide qualitative data on gamma background radiation?

LIMITED DISTRIBUTION: Copyright© 2000 by the Institute of Nuclear Power Operations. Not for sale nor for commercial use. Unauthorized reproduction is a violation of applicable law. Each INPO member and participant may reproduce this document for its business use. This document should not be otherwise transferred or delivered to any third party, and its contents should not be made public, without the prior agreement of INPO. All other rights reserved. NOTICE: This information was prepared in connection with work sponsored by the Institute of Nuclear Power Operations (INPO). Neither INPO, INPO members, INPO participants, nor any person acting on the behalf of them (a) makes any warranty or representation, expressed or implied, with respect to the accuracy, completeness, or usefulness of the information contained in this document, or that the use of any information, apparatus, method or process disclosed in this document may not infringe on privately owned rights, or (b) assumes any liabilities with respect to the use of, or for damages resulting from the use of any information, apparatus, method, or process disclosed in this document. HPT001.009B Revision 3 Page 36 of 42 Appendix 4

Radiography Unplanned dose and engineered safety feature actuations have occurred during radiography because of inadequate radiation safety practices and worker knowledge. Events

Location: Texas Overexposure During Radiography -- Reference: IN 99-04 On December 31, 1998, a radiography trainee received 10 rem whole body dose and a dose of 3,000-5,000 rem to the index finger when he forgot to retract the radiographic source after a radiographic shot. Important Points:  The trainee left his TLD and alarming dosimeter in his truck.  The trainee did not use a survey meter to verify the source was locked before handling the end of the guide tube with the radiographic source in it. Contributor:  The qualified radiographer assumed the trainee was qualified, and the trainee assumed the radiographer knew he was a trainee.

Plant: Diablo Canyon Unit 2 Overexposure Because of Equipment Failure and Personnel Error -- Reference: LER 323-91008 On September 19, 1991, after completing a radiograph, two radiographers, preparing to take additional radiographs of piping welds, received 3 rem and 15.2 rem whole body doses because the radiation source was not completely retracted into the shielded camera. Important Points:  The radiographers did not survey the camera as required by procedure to verify the source was fully retracted.  The radiographers did not attempt to lock the source in the stored position between radiographs as required by procedure. Contributors:  The radiographers did not use alarming ratemeters.  The survey meter being used had not been checked for response on all scales, and it was not working properly.  Misaligned and bowed parts in the camera prevented the source from being fully retracted.

Plant: Dresden Unit 1 Two workers Receive Unplanned Exposure Following Entry Into a Radiography Area -- Reference: IN 93-69 On February 13, 1993, two workers received unplanned doses when they made an unauthorized entry into a posted radiologically controlled area established for radiography. Important Point:  The two workers disregarded radiological postings and entered a controlled area.

Contributor:  The radiographers and radiation protection technician did not verify the radiologically controlled area was free of personnel prior to starting work after a HPT001.009B Revision 3 Page 37 of 42 break.

Plant: Hatch Unit 2 Radiation From Radiography Initiates Engineered Safety Features -- Reference: LER 366-92016 On September 22, 1992, during refueling, radiation from a source being used to radiograph a weld was detected by reactor building radiation monitors and activated the trip system for the standby gas treatment system (SGTS) and secondary containment isolation system. SGTS automatically initiated, and the secondary containment isolation dampers automatically isolated.

Important Points:  Licensed personnel did not realize that radiation from the radiography activities would cause the radiation monitors to activate the engineered safety features.  Licensed personnel were unaware of the proximity of the radiography activities to the radiation monitors. Contributor:  The radiography was performed approximately 50 feet from the radiation monitors.

Important Considerations for Radiographic Work (Lessons Learned)  What effects will radiography activities have on plant equipment? How have we verified that unplanned equipment actuations will not occur as a result of these activities? How have we communicated these radiographic locations to licensed operators in the control room?  How have we independently verified the radiography area is properly roped off, posted, and kept free of unauthorized personnel by the radiographers? What access control procedures and mechanisms have we established to prevent entry into the radiography area during radiography? How have we informed plant and contractor personnel of the temporarily roped off, radiologically controlled areas for radiography?  How have we verified that radiographers are trained in the proper radiography safety practices?  How have we verified that radiographers are using communication techniques, such as three-way communication, that will effectively prevent miscommunication of source position?  What self-checking techniques will we use during radiography to prevent unplanned radiation dose? When will they be used?  What are some improper actions that, if taken, could quickly lead to serious radiation doses to the whole body and extremities and potential injury from radiographic source exposure? What actions have we taken to prevent this? What are the radiation work permit requirements?  What radiation detection instruments are required for radiographic work? Why is it necessary to use different types of radiation detection instruments during radiography? How have we verified that radiographic workers, at a minimum, are wearing alarming ratemeters, pocket ion chambers (PIC) or electronic dosimeters, and thermoluminescent dosimeters (TLDs)?  How do we verify radiation detection instruments, such as survey meters and alarming dose rate meters, are properly functioning on all scales? When is this verification required?  What action must be taken if an alarming ratemeter alarms?  What steps will we take to verify that the source in a radiography camera is not out of its shield when it should be shielded or locked in the camera?  When must the source be locked inside the camera? How will we verify the source is actually locked when it is retracted into the camera? When is this verification required? How have we verified the camera and equipment, such as the locking mechanism, are in good mechanical condition and function properly?  How have we communicated the frequency of visually checking direct reading dosimeters?  What are radiographer work expectations for reporting nonconforming conditions? Who should radiographers notify regarding equipment irregularities?  What monitoring requirements have we established for these radiographic work activities? How have we verified that our monitoring practices ensure compliance with technical and safety requirements?  How have we verified the adequacy of radiographer emergency procedures and source retrieval procedures? HPT001.009B Revision 3 Page 38 of 42

Appendix 5

Hot Particle Work Area Radiological controls of work areas have not prevented the spread of hot particles to unwanted areas increasing the risk of personnel radiation exposure.

Events Plant: Prairie Island Unit 1 Potential Overexposure Because of Inadequate Radiation Work Oversight—Reference: OE 12059 On January 31, 2001, while performing maintenance on a safety injection cold leg check valve during a refueling outage, a hot particle (600 rem per hour gamma on contact) was found to have dislodged from the shielded area of the valve internals. The particle was found adjacent to the scaffold platform exposing two maintenance workers to an uncontrolled radiation field. Important Point:  Radiation protection work planning and work practices were inadequate. Contributors: A radiation protection supervisor determined that the requirements of the hot particle program were not applicable because the definition of a hot particle area was not met, even though it was known that a hot particle existed within the valve for several years. The assigned radiation protection supervisor did not immediately stop work or urge the workers to leave the area when indication of general radiation levels increased from 15 mrem per hour to 250 mrem per hour. Plant: Susquehanna Unit 1 Highly Radioactive Particles Associated With Fuel Pool Work -- Reference: OE 11779, SER 3-01 On October 12, 2000, an advanced crusher and shearer (ACS) unit used to crush control rod blades was removed from the fuel pool and stored on the refueling floor. Following ACS removal and transfer, three discrete radioactive particles (DRPs) with contact dose rates of up to 800 rem per hour were discovered on the refueling floor. These high activity particles did not come in contact with personnel. During subsequent cask packaging and shipping evolutions, three additional particles were identified with measured dose rates of up to 220 rem per hour. One particle with a dose rate of 1 rem/hr was found adhered to a worker’s protective shoe cover. Important Points: Managers were aware of the potential for DRPs to be present; however, the magnitude of the dose rates that were encountered was not anticipated. There was previous plant experience with DRPs in excess of 100 rem per hour when this evolution was performed in 1991, but this information was not widely known, nor was it incorporated into planning for this evolution. Contributors: Contingency plans or actions to be taken if DRPs were HPT001.009B Revision 3 Page 39 of 42 encountered in other than controlled areas were not developed. Turnover to the evening shift occurred while work continued, potentially distracting individuals from receiving needed information. Clear expectations regarding DRP controls for the travel path during the transfer of the ACS were not established. Although workers believed DRPs might be present, a DRP check of the unit was not required by the work package nor was one completed before the transfer of the ACS began. Because of the ACS design, and the inability to hydrolaze in an upward direction, portions of the unit could not be effectively cleaned. The ACS was not rinsed with demineralized water as it was raised from the fuel pool as had been the practice in the past to help remove potential DRPs.

Plant: Surry Unit 2 Radioactive Particles Detected at Protected Area Exit -- Reference: OE 10083 Between April 20 and May 21, 1999, during the refueling outage, there were seven cobalt-60 hot particle personnel contamination events (PCE). The hot particles escaped detection at the radiological controlled area (RCA) monitors but were detected by the protected area exit monitors as the workers were leaving the station. During separate instances, seven individuals exiting the protected area were identified by monitors as having levels of 3,000-dpm to 300,000-dpm of hot particle activity. Important Point: The increase in hot particle contamination was attributed to the reduced scope of containment and scaffold decontamination. Contributor: The personnel contamination monitors at the RCA exit were relatively insensitive to the higher energy cobalt-60 gamma radiation and may not detect beta radiation if shielded by clothing or in a location of poor geometry relative to the monitor. Plant: Prairie Island Unit 1 Radioactive Hot Particles from Incore Instrumentation Work -- Reference: OE 9329 On June 12, 1998, the radiation protection specialist group noticed an increased number of individual contamination cases from work in containment. These cases followed the forced shutdown to repair several leaking incore instrumentation thimble tube seals. Thirteen separate radiation occurrences were recorded involving 11 individuals. Important Point: Relevant information about hot particles had been omitted from previous post-work ALARA reviews therefore, this information was not incorporated into the incore instrumentation work. Contributors: Sticky pads were not used as prescribed by procedure. Less than adequate radiological work practices were identified. Lack of proper labeling existed at the job site. Less than adequate planning regarding communication methods when wearing certain protective equipment. HPT001.009B Revision 3 Page 40 of 42 Less than adequate training for identifying the location of special tags and equipment used for hot particles. Important Considerations for Hot Particle Work Areas (Lessons Learned)  What contamination controls should be used when a contaminated piece of equipment is moved? What is the most effective way to communicate these controls to personnel involved with the task?  What course of action should be taken if hot particles are anticipated? What course of action should be taken if hot particles are identified?  What controls should be considered prior to retrieving a hot particle? How do we consider dose, particle movement, and difficulty of removal?  How do we capture radiological lessons learned at the completion of our task?  What are the hazards associated with hot particles? How do we communicate the potential hazards to those involved?  How do we ensure prejob briefs are sufficiently in-depth and inform workers of the radiological risks associated with the task to be performed?  Under what conditions do we expect radiological technicians to stop work in the field?  When should a hot particle control zone be established? When should a check of hot particles be made?  What monitors should be used considering the type of contamination anticipated?  What training is required to support the task if hot particles are anticipated?

LIMITED DISTRIBUTION: Copyright© 2001 by the Institute of Nuclear Power Operations. Not for sale nor for commercial use. Unauthorized reproduction is a violation of applicable law. Each INPO member and participant may reproduce this document for its business use. This document should not be otherwise transferred or delivered to any third party, and its contents should not be made public, without the prior agreement of INPO. All other rights reserved. NOTICE: This information was prepared in connection with work sponsored by the Institute of Nuclear Power Operations (INPO). Neither INPO, INPO members, INPO participants, nor any person acting on the behalf of them (a) makes any warranty or representation, expressed or implied, with respect to the accuracy, completeness, or usefulness of the information contained in this document, or that the use of any information, apparatus, method or process disclosed in this document may not infringe on privately owned rights, or (b) assumes any liabilities with respect to the use of, or for damages resulting from the use of any information, apparatus, method, or process disclosed in this document. HPT001.009B Revision 3 Page 41 of 42 Appendix 6 Just-In-Time Operating Experience

Radioactive Filter Handling Rev. 1, April 2001 Draining and handling radioactive filters without proper prejob briefs, radiation protection controls, ventilation, and postings has resulted in unanticipated dose rate changes and in the contamination of personnel and work areas. Events Plant: San Onofre 2 Unanticipated Dose Rate Change During Filter Isolation and Draining -- Reference: OE 11998 On November 16, 2000, during valve lineups for a reactor coolant radwaste filter changeout in a normally locked high-radiation area room, an operator received a minor unanticipated radiation exposure. A health physics (HP) technician met the operator outside of the room to be entered and opened (unlocked), surveyed, and downposted the room to a high-radiation area greater than 100 mr/hr but less than 1 R/hr. The HP technician was under the assumption that the operator had already bypassed and drained the filter from the remote panel as he had observed in past evolutions. However, the operator briefly left the room, remotely opened the filter’s vent and drain valves, and returned. Water, normally in the piping then drained, unshielding existing hot spots and increasing the general area dose from 50-200 mR/hr to 1-6 R/hr. A personal exposure dosimeter alarmed and both the operator and HP technician exited the area. Important Points:  The operator did not recognize that draining the filter had the potential to change radiological conditions in the room.  The prejob brief did not include a discussion of the likelihood that draining the reactor coolant filter could produce high dose rates in the room or a specified sequence of how the activity was to be performed. Contributors:  The work authorization guideline did not caution the operator of possible high transient dose rates in the room.  The HP technician did not inquire as to why the operator briefly left the room, assuming that the filter had previously been drained and vented. The operator did not tell the HP technician what he was planning to do. Plant: D. C. Cook 1 and 2 Personnel Contamination While Loading Filters into High Integrity Container (HIC) -- Reference: OE 11448 On August 15, 2000, while loading highly contaminated spent system filters into a HIC destined for disposal, three technicians involved were contaminated (two received positive whole body counts as well). Seven filters had been loaded without incident, but the last two filters would not enter the HIC without manual manipulation. The technician assigned to view filter position climbed a ladder leaning against the shielded cask and maneuvered the filters into the HIC with a mop handle. Important Points:  The radiation work permit did not address the aspect of handling dry filters, filter mishandling incidents, airborne radioactive material control or prevention.  The prejob brief did not consider filter dryness during contingency actions. A hold point that was discussed regarded a dropped a filter, but the technicians did not recognize that a filter not dropping completely into the HIC would have the same potential for producing airborne contamination. Contributors:  There was a lack of adequate supervisory oversight. One of the technicians was assigned the lead, but was also required to operate the crane and perform surveys of the filters.  The HIC was expected to contain approximately 100 filters, but the problem HPT001.009B Revision 3 Page 42 of 42 occurred with filters 68 and 69. If the filling of the HIC had been adequately monitored to observe the remaining free capacity, the technician could have rearranged the filters in the HIC prior to trying to load these filters. Plant: North Anna 1 Personnel and Area Contamination During Reactor Coolant Filter Transfer -- Reference: OE 8924 On March 16, 1998, dry, loose contamination was released during transfer of a reactor coolant letdown filter from a transport cask into a temporary storage cask for decay. One worker was contaminated, two others received contamination on their clothing, and loose contamination was spread over approximately 1,400 square feet of the plant. Important Points:  It was not recognized that the extended drying of the filter over a four-day period, between filter removal and transfer to a temporary storage cask, increased the potential for spreading contamination from the filter.  The personnel transferring the radioactive filter did not adequately use ventilation or containment controls to prevent the spread of loose contamination. Contributors:  The filter was left in service after it exceeded the changeout dose rate limit, which resulted in a higher than normal activity level during changeout.  The work controls addressed routine conditions. They were not adequate for handling the dry, highly contaminated filter. Important Considerations for Radioactive Filter Handling Activities (Lessons Learned)  How can we heighten our awareness of potentially changing radiological conditions/hazards when handling filters?  How are we going to minimize filter dry out prior to removal?  How will draining the water from a filter change the radiological conditions in the area?  How can we alert personnel of potential work hazards from loose or airborne contamination, especially when filters have dried out after draining?  How have we verified the survey results for activity levels and expected doses associated with the filter-handling job? How has historical filter activity data been used to determine expected levels? If activity levels were not as expected, how did we resolve the differences?  How was the potential for filter degradation considered in planning for the activity?  How often will work area conditions be monitored by radiation protection personnel?  What techniques are we using to control contamination?  How have we verified the adequacy of engineering controls and protective equipment for the filter handling?  How did we verify that local area and personnel radiation monitoring equipment is operable?  How have we verified that all equipment required for the work, such as special tools, filter storage casks, and parts, are readily available?  How have we verified that the work instructions and radiation work permit are specific enough to ensure control of the radiological conditions in the work area and adjacent areas?  How have we communicated expectations to notify radiation protection and supervision to reevaluate radiological conditions if we encounter unexpected conditions or delays during the filter handling?  What are our contingency plans for equipment failures that could potentially increase radiological hazards? What additional protective equipment, such as respirators, may be needed?  What filter conditions are we to pass on to the next crew when filter handling work is delayed or extended?  How have personnel using radiation monitoring instruments for the filter-handling job demonstrated proper use of the instruments and knowledge of instrument limits?  What lessons from previous radioactive filter handling work at the station have we applied to this job?

LIMITED DISTRIBUTION: Copyright© 2001 by the Institute of Nuclear Power Operations. Not for sale nor for commercial use. Unauthorized reproduction is a violation of applicable law. Each INPO member and participant may reproduce this document for its business use. This document should not be otherwise transferred or delivered to any third party, and its contents should not be made public, without the prior agreement of INPO. All other rights reserved. NOTICE: This information was prepared in connection with work sponsored by the Institute of Nuclear Power Operations (INPO). Neither INPO, INPO members, INPO participants, nor any person acting on the behalf of them (a) makes any warranty or representation, expressed or implied, with respect to the accuracy, completeness, or usefulness of the information contained in this document, or that the use of any information, apparatus, method or process disclosed in this document may not infringe on privately owned rights, or (b) assumes any liabilities with respect to the use of, or for damages resulting from the use of any information, apparatus, method, or process disclosed in this document.