ML20054E763
| ML20054E763 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 06/04/1982 |
| From: | Blomgren J COMMONWEALTH EDISON CO. |
| To: | |
| Shared Package | |
| ML20054E730 | List: |
| References | |
| ISSUANCES-OL, NUDOCS 8206140180 | |
| Download: ML20054E763 (20) | |
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UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION l
BEFORE THE ATOMIC SAFETY AND LICENSING BOARD In The Matter of )
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COMMONWEALTH EDISON COMPANY ) Docket Nos. 50-454 OL !
) 50-455 OL l
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(Byron Nuclear Power Station, )
Units 1 & 2) )
AFFIDAVIT OF JOHN C. BLOMGREN The attached questions and answers constitute my testimony in the above-captioned proceeding. The testimony is true and accurate to the best of my knowledge, information and belief. - .
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John C. Blomgren SN?W Subscribed and sw r to before me this .
day of '_h m>.. , 1982.
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O F206140100 820607 PDR ADOCK 05000454 PDR O
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7FFIDAVIT OF JOHN C. BLOMGREN O ON DAARE/ SAFE CONTENTIONS 8 AND 9 (e)
Q.l. Please state your name and present employer..
A.l. My name is John C. Blomgren. I am employed by Commonwealth Edison Company and am a member of the Technical Services-Nuclear Department Staff.
0.2. Would you please briefly summarize your educa-tional background and professional qualifications.
A.2. I received a Bachelor of Science Degree in Chem-istry from Aurora College in 1969, and earned a Master of Science Degree in Nuclear Engineering from Penn-sylvania State University. I joined Commonwealth Edison Company in 1971 as an engineer on the' Technical Staff at Zion Station and held several positions on the Zion Station Staff until .Tanuary, 1978.
From June, 1974 to January, 1978 I was the Radi-ation Protection and Chemistry Supervisor at Zion Station. I supervised a group of engineers, health physicists, chemists, and technicians responsibla for e conducting the station health physics and chemistry i
program.
i' In January, 1978, I was assigned as a project manager, for research and development projects, to the Production Department Staff, and in September, 1979
() this group became the Technical Services-Nuclear i
Department. My responsibilities are to supervise a group of engineers who iaaaage research, development and demonstration projects in the areas of decontamination, chemical cleaning, water chemistry improvement, and steam generator technology. As part of these respon-sibilities I participated as a member of the Steam Generator Owners Group, Technical Advisory Committee, and as chairman of that committee's Chemical Cleaning Subcommittee. Since 1977, I have been involved in the technical management and development of plant decon-tamination programs.
Q.3. Have you been asked to prepare written testimony to respond to DAARE and SAFE's contention No. 8?
A.3. Yes. Contention 8 reads as follows:
"Intervenors contend that Applicant does not meet the requirements of 10 C.F.R. Part 51.21'and 51.20(a), (1 and 2); (b), (c) be-cause no consideration is given the environ-mental impact of primary coolant system chem-ical decontamination and steam generator chem-ical cleaning which the Department of Energy has determined will occur twice during the lifetime of a nuclear power plant. Recent data raise the possibility of serious adverse consequences of the decontamination process.
Chelating agents, intended for the removal of highly radioactive corrosion products ad-herent to the coolant system surfaces, sharp-ly increase the rate of :nigration of these same radioactive products through the envi-ronment and into the food chain. No analysis or discussion is given possible biological consequences to the accidental spillage during decontamination, waste storage, transportation or disposal (on or off-site) . "
O Q.4. What is the primary coolant system decontamination
(' ~S and steam generator chemical clean'ing to which this V
contention refers?
A.4. Decontamination is the process whereby metal oxides (magnetite, hematite and various spinels) which form on the interior surface of the primary system are removed. These oxides are almost identical to oxides which would form on the surfaces of any piping system exposed to high temperature water or steam. However, in a nuclear power plant, radioactive materials which are present in the primary coolant are bound with the oxides on the metal surfaces. The radioactive atoms constitute an extremely small percentage of the total number of atoms in the oxide film, and therefore, removal of the contaminants from the system can be performed using techniques similar to techniques which have been used for many years to remove contaminants from surfaces in other industrial processes. '
The presence of radioactivity in the oxide film does present two unique problems. First, the small amount of radioactivity in the oxide film increases the radiation field in the vicinity of the affected piping, and contributes to occupational radiation exposure of the plant personnel. The purpose of the decontamin-
- ation is to reduce the exposure of operating and main-tenance personnel. For example, as a result of chem-ical cleaning of the Company's Dresden Unit I facility,
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over a ten-year period, occupational expenses will be V
reduced by 7,500 to 12,500 man-rems. Second, because the contaminants removed from the primary system of a nuclear plant contain radioactive materials, they must be handled and disposed of as are other low level wastes.
Q.5. If primary system decontamination is required at Byron, will there be any significant adverse impact to the quality of the human environment?
A.S. No. The Company has studied the potential en-vironmental eftects of chemical decontamination in connection with its plans to decontaminate Dresden Unit
- 1. No significant liquid or gaseous radioactive effluents are expected to be released into the environ-ment. The solidified radioactive wastes containing the radioactive materials removed from the primary coolant system at Dresden Unit 1 will be less in volume and in radioactive content than the amount of low level radio-
- active waste generated at and shipped from the Dresden site in 1979. During that year Units 2 and 3 at Dresden
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were in service. The NRC Staff concluded that the chemical cleaning of Dresden Unit 1 would not significantly affect the quality of the human environment. -*/ Work is
-*/ NUREG-0686--Final Environmental Statement related to Primary Coolant System Chemical Decontamination at gg Dresden Nuclear Power Station, Unit No. 1 (October, v 1980).
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underway by several organizations which will result in significant advances in the state of the art of decon-tamination when and if the Byron Station is chemically cleaned, but the environmental impacts of decontamin-ation are expected to be similar to the insignificant impacts for the Dresden Unit 1 decontamint ; ion. The impact of future chemical cleaning would be very small compared with the radiological impacts of routine operation of Byron.
Q.6. The Contention makes special reference to the use of chelating agents in the chemical cleaning process.
Does the Company expect that chelating agents will be part of any cleaning solution used to chemically clean the Byron Station?
A.6. Based upon decontamination work that has been going on over the past ten years, one would expect chelating agents to be present in waste generated from a chemical decontamination at Byron. Most modern chemicals used for chemical cleaning do contain chel-ants. However, it is by no means certain that, if the Byron Station requires decontamination at some future I
time, it would be accomplished through the use of chemical solvents with chelants. Decontamination methods exist today which do not require the use of O
chelants, including mechanical decontamination, electro-() polishing of metal surfaces and chemical reduction techniques. Prior to selecting the method proposed for decontamination of Dresden Unit 1, the Company reviewed a number of alternatives. For that particular applic-ation, we selected a solvent containing chelants.
Q.7. Do you know if chelating agents have ever presented any special problems in the disposal of radioactive wastes?
A.7. Yes, they have. At one time radioactive wastes containing chelants were disposed of at government facilities in liquid form in shallow trenches. If these liquids escaped from the containers in which they were buried, the chelating agents allowed the radio-active materails to be transported through the ground water at a rate higher than would have been the case without the presence of chelating agents.
Q.8. Is this a fairly well understood phenomenon now?
A.8. Yes, it is well understood.
Q.9. Is it the Company's intent to dispose of any radioactive wastes which may be associated with any
- chemical cleaning of the Byron Station without first solidifying them?
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.- A.9. No. I fully expect that solidification of liquid O wastes from chemical cleaning _would be performed at all relevant times in the future.
Q.10. Describe what Edison would propose, based on the state of the art today, for the disposal of radioactive wastes containing chelants.
r A.10. Based on our experience and development of the Dresden I decontamination project, our intention would be to encapsulate any such waste in a polymer binder which is not soluble in water. In this process, the concentrated wastes from decontamination are mixed with the binder materials and poured into steel drums.
The waste / binder mixture then dries into a solid mass.,
This process allows for disposal of the waste as a solid, not as a liquid. It also permits disposal of the waste in a form which practically eliminates any potential for migration of the radioactive materials.
These solidified wastes would be disposed of in an 7 arid, government approved low level waste disposal site. These wastes would be segregated from other
( general wastes at the site and would be buried in a separate trench.
Q.ll. What is the purpose of segregating these wastes from general waste?
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A.'ll. This provides an additional level of assurance
- [J S that there would be no interaction between the waste in a given burial trench that might change the pro-perties of the solidifying agent.
Q.12. Does the method of disposal you have described eliminate the problem of rapid migration through ground water of radioisotopes observed with some early disposal of low level wastes with chelants?
A.12. Yes, it does. There are two levels of assurance provided to prevent migration through ground water:
The wastes are made essentially immobile by the polymer binder and isolated from ground water by selection of an arid site. The NRC Staff reviewed the described method of waste disposal in connection witi the Fin.al Environmental Statement prepared for the Dresden I de-contamination project and concluded that the disposal of the wastes presented no significant environmental impact. The use of chelating agents in any chemical cleaning of the Byron Station can reasonably be ex-pected to pose no threat to the environment.
Q.13. In the event that the Company found it necessary to chemically clean or decontaminate the Byron Station, t
is it the Company's intent to obtain all required Nu-clear Regulatory Commission authorization for the (G_)
methods proposed and to abide by any limits the Nuclear Y^^
U Regulatory Commission might impose on the disposal of any wastes generated?
A.13. Yes.
Q.14. DAARE/ SAFE also contends that the presence of chelating-agents presents special problems in the event of accidental spillage during the decontamination process, storage of the waste, transportation or disposal of the waste. Do chelating agents present any special problem in the event of accidental snillage during the decontamination process?
A.14. Typical plant waste clean-up systems include evaporation and ion exchange capabilities. Any wastes containing chelants will be effectively cleaned up in the nornal waste systems. If a spill were to occur on the ground outside of the plant, it might be necessary to dig up the contaminated soil and process the soil itesif as a solid waste. Therefore, the presence of chelating agents would noi change the characteristics of the wastes to make the vastes any more harmful, nor are the chelating agents themselves a potential threat.
Edison would simply have to take the precautions it is required to and normally does take when it handles any contaminated liquids. The chelating agents do not present any unique problems at this stage.
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,. Q.15. Does chemical decontamination present any signif-( icant problems with respect to the need to store resulting wastes on site or transport them to a waste storage facility?
A.15. No. Once the wastes have been solidified in the polymer binder, and have been placed in steel drums, they are no different than the other low level solid wastes which will be handled routinely at the Byron Station and shipped to licensed dispcsal sites. Any wastes generated during chemical decontamination will be a very small fraction of the total volume of low level waste which will be generated at and shipped from the Byron Station during its useful life.
Q.16. Would you summarize your evaluation of any special problems that may be associated with the ase of chel-ants as part of a chemical decontamination program?
A.lE. The disposal of radioactive waste containing chelants is not different in my opinion from the disposal of other plant radioactive waste as long as the chelant is solidified. Once the wastes are en-capsulated in a polymer binder, the transportation, on-site storage, and on-site handling of the waste would not be different from the handling of other wastes.
The solidified waste would be buried in a segregated i
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. 1 y3 area of an arid waste disposal site to eliminate the V
possibility of other chemicals coming into contact with i
the solidified plastic that might degrade the inteJrity 1 of the solidified plastic. Therefore, I do not believe that the handling of chelated wastes represents any significant problem as compared with handling wastes of similar concentrations of radioactivity.
The Nuclear Regulatory Commission Staff carefully analyzed potential environmental consequences of chem-ical decontamination of the Dresden I Power Station using solvents and chelating agents. They came to the same conclusion as I have expressed. The decontamin-ation process can be performed without presenting any significant harm to the environment.
Q.17. Have you read DAARE/ SAFE's Contention 9 (e) ?
A.17. Yes. Contention 9 (e) asserts that decontamination of the Byron Station may cause degradation of the Byron Station primary coolant system boundary, and may there-fore present a safety problem.
Q.18. In your opinion, will chemical decontamination of the Byron Station, if done, " exacerbate safety problems through a degradation of the integrity of the primary coolant system boundary"?
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,. A.18. No. Chemical, cleaning and decontamination of l various types of metal surfaces has been done for years by electric utilities and other industries. Based upon
- these years of experience, solvents used to chemically clean the Byron primary coolant system will be both effective and safe. For purposes of decontamination the deposits to be removed from the primary coolant system, and the materials making up the coolant system boundary do not differ from deposits and materials previously encountered in cleaning processes. Several of these processes have been effectively applied over the past several years at nuclear reactors throughout the world.
Q.19. Are the nature of the deposits that can be ex-pected to accumulate at Byron presently known?
A.19. Yes. PWR deposits are typically a mixture of magnetites and chromium and nickel spinels. These are oxides of the various metals used in pressure versel and primary system piping. The oxide deposits will be contaminated with a relatively very small amount in i
l terms of weight, of radioactive isotopes. The amount of radioactive contamination does not affect the char-
) acter of the oxide deposits from the standpoint of cleaning. The radioactive contamination affects the cleaning process only to the extent that materials
v removed from the system must he handled as radioactive
]\ wastes. There are a variety of available solvents which would be effective in removing the oxide deposits from the primary coolant system.
Q.20. Do there presently exist solvents which are capable of removing these deposits from the type of metal surfaces in the cooling system without damaging the integrity of the metal?
A.20. Yes. Based on decontamination experience to date, we know that chemicals and processes have been applied to similar material surfaces and have successfully de-contaminated the component surfaces without adversely affecting the integrity of the system. Based on the development effort that has gone on in the past, I am confident that a similar process can be applied for the decontamination of Byron Station if needed. Prior.to decontaminating Byron, we would verify that the solvent and process selected would be effective to clean the system and would not be detrimental to the integrity of the system.
l Q.21. Can the primary coolant system be adequately flushed following any chemical decontamination so as to prevent the solvents used from causing degradation during subsequent operation of the reactor?
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A.21. It is possible that future developments will e
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(/ include the use of chemicals that would not have to be flushed from the reactor coolant system at all. How-ever, cleaning agents th.tt are currently in use can be adequately removed from the system by flushing so as to prevent degradation during subsequent operation-of the system.
Q.22. Will chemical decontamination add to the total level of radioactive contaminants on the surfaces of tLe primary coolant boundary?
A.22. No. The cleaning process reduces the radioactive inventory of the system. The act of decontamination will not increase the deposition of radioactive cor-rosion products.
Q.23. Are you aware of any discussion of the potential for chemical decontamination to alter the rate at which the radioactive materials in the primary coolant system are deposited on the surfaces cleaned?
A.23. Yes. After the decontamination of a small test loop at Dresden Unit I and subsequent operation of the Unit, a rapid increase of the radioactivity levels on that particular system was observed. However, the operation of the system was sporadic and on a close
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review of the data it becomes very unclear as to why e
the rapid build-up rate in that case was observed.
(")T More recently, several large system decontaminations have been conducted on operating power reactors. In.
none of these recent cases has there been a rapid increase in activity after the decontamination. In fact, the radioactivity levels have remained below the .
level prior to decontamination for the one to two years of reactor operation which has occurred to date since the decontamination. Based on this recent experience, there is no reason to believe that partial system decontamination will add to the deposition of corrosion products. Full system decontamination will result in the removal of corrosion products from all surfaces in the system. Ccnsequently, for full system deconta. min-ation, there is even less reason to think there would be an accelerated buildup of corrosion products.
O 9 (a) -1 DAARE/ SAFE CONTENTION 9(a) g>
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CONTENTION 9(a)
Intervenors contend that there are many unresolved safety problems with clear health and safety implica-tions and which are demonstrably applicable to the Byron Station design, but are not dealt with adcquately in the FSAR. These issues include but are not liaited to:
- a. Serious water hammer problems. We understand that a water hammer caused by rapid condensation of steam in feedwater lines of a PWR constitutes the most serious of this sort of event. Damage to pipes and valves are some potential hazards.
Ultimately, under the most serious circumstances successive, water hammer incidents might lead to a loss of coolant accident. Applicant has already had water hammer problems in its Zion plant in 1977, and a plant shutdown was required to repair the damage. The similarity of plant equipment, management, and operator training programs between the Zion and Byron stations raises serious ques-tions about the Applicant's ability to operate the Byron plant safely, with respect to water hammer phenomenon. Evidence with respect to demonstrated efficacy of new nozzle designs to be used at Byron to mitigate water hammers is not presented at FSAR 10.4.7.3.
MATERIAL FACTS AS TO WHICH THERE IS NO GENUINE ISSUE TO BE HEARD
- 1. The steam generators installed at Byron are preheat, counterflow type steam generators designed by Westing-house Electric Corporation. (Affidavit of Robert W.
Carlson, at p. 7.)
- 2. The Byron design includes a feedwater bypass system which provides for the introduction of cold feedwater (water at a temperature of less than 250*F) into the steam generator through an auxiliary nozzle located approximately 45 feet from the bottom of the steam
9 (a) -2 generator vessel. (Affidavit of Robert W. Carlson, pp.
C 8, 12-13.)
- 3. The design of the feedwater bypass system is based upon a series of tests conducted by Westinghouse which demonstrate that bubble collapse water hammer events are unlikely where the temperature of feedwater intro-duced through the main feedwater nozzle is greater than 250'F. (Affidavit of Robert W. Carlson, pp. 11-12.)
- 4. Westinghouse has recommended certain modifications to the feedwater bypass system, which if implemented at Byron will assure that the bypass system will effectively reduce the likelihood of bubble collapse water hammer events in the steam generators. These modifications involve the installation of temperature sensors in the bypass system to discover the existence of circumstances which could lead to bubble collapse water hammer in the bypass system. (Affidavit of Robert W. Carlson, pp.
17-19.)
- 5. Commonwealth Edison is currently investigating the possibility of installing temperature sensors in loca-tions other than those recommended by Westinghouse.
(Af fidavit of Leslie A. Bowen, p. 4).
l 6. If suitable alternative locations are found, Edison will install the temperature sensors in these locations.
l Otherwise, Edison will install the temperature sensors at the locations previously recommended by Westinghouse.
' (Affidavit s. Leslie Bowen at p. 4.)
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- 7. The Operating Procedures for operation of the feedwater O)
\_ bypass system will implement the suggested general operating procedures provided by Westinghouse for operation of that system. (Affidavit of Richard Pleniewicz, at p. 3.)
DISCUSSION Contention 9a concerns water hammer events caused by rapid condensation of steam in feedwater lines. The Affidavit of Robert W. Carlson describes this phenomenon (referred to as bubble collapse water hammer). His affida-vit then describes the design of the Byron steam generators, including the design of the feedwater water bypass system.
The design of this system is based upon tests conducted under Mr. Carlson's supervision, the results of which demon-strated that if the temperature of feedwater is above 250'F it is highly unlikely that bubble collapse water hammer events will result from the introduction of feedwater into the steam generators through the main feedwater nozzles. To assure that " cold" feedwater (i.e. water below 250 F) is not introduced through the main feedwater nozzle, the Byron Station design includes a feedwater bypass system, which introduces feedwater through a nozzle located approximately two-thirds of the way up the steam generator vessel. In this way, the " cold" feedwater will not be introduced direct-ly into the preheater section of the steam generator.
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Mr. Carlson also explains that Westinghouse has q\/
recommended a design modification to the feedwater bypass system which essentially provides for the installation of temperature sensors on the feedwater bypass system to monitor l
conditions in this system, which could possibly give rise to bubble collapse water hammer events in the piping system.
The affidavit of Leslie Bowen explains that Commonwealth Edison agrees that there should be temperature sensors installed to monitor bypass piping conditions, and that these modifications will be implemented at Byron. Ms. Bowen also states that, at present, Edison is performing an evalu-ation to determine whether there are suitable locations for the piping temperature sensors other than those recommended by Westinghouse. However, Ms. Bowen states that the final decision as to the location of the temperature sensors will be subject to Westinghouse approval.
Finally, Richard Pleniewicz states that Edison will develop operating procedures which are consistent with the recommended ge.neral operating procedures which are con-sistent wi mh the recommended general operating procedures provided by Westinghouse.
No factual issue has been raised by DAARE/ SAFE Contention 9a which controverts the facts established in the affidavits of Messrs. Carlson and Pleniewicz and Ms.
Bowen. Accordingly, Edison is entitled to a favorable decision on the Contention as a matter of law.
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