Affidavit Re Environ Qualification & Aging of Safety-Related Electrical
Total Page:16
File Type:pdf, Size:1020Kb
UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE ATOMIC SAFETY AND LICENSING BOARD In the Matter,0f: PACIFIC GAS AND ELECTRIC COMPANY Docket Nos. 50-275 O.L. (Diablo Canyon Nuclear Power 50-323 O.L. Plant Units I and 2) AFFIDAVIT OF THOMAS G. DUNNING I, Thomas G. Dunning, being duly sworn, do depose and state: l. I am employed as a Section Leader by the Instrumentation and Control Systems Branch (ICSB), Division of Systems Integration, Office of Nuclear Regulation, USNRC. A complete description of my professional qualifications is attached to this affidavit. 2. The purpose of re affidavit is to address factual matters raised 'by Joint Intervenors motion to reopen the record in the above captioned proceeding and the "Affidavitof Mr. Richard Burton Hubbard" (February 28, 1980) with respect to environmental qualification and aging of safety-related electrical equipment. 3. The affidavit of Mr. Hubbard states, among other things that: "... new factors pertinent to the Diablo Canyon Station (with respect to NUREG-0588 For Comment) ... demonstrate the need for additional review of environmental qualification of the safety-related structures, systems, and components. My affidavit demonstrates that the information on the qualification program for safety-related items should include (a) an identification of all Diablo Canyon Class I safety-related equipment and (b) an evaluation of aging effects on the qualification of all Diablo Canyon Class I safety-related equipment." (Affidavit, at 3). "... lists of Category I structures, systems, and components provided to assure (a) the integrity of the reactor coolant boundary, and (b) the capability to shut down the reactor and maintain it in a safety condition are general and are not sufficiently complete for purposes of documenting equipment qualification parameters. Further, my investigations indicate that the effects of aging have not been properly considered in the seismic and environmental qualification of safety-related equipment. (Affidavit, at 11-12). 4. Two NRC letters to the applicant, dated November 2, 1979 and February 5, 1980 and NUREG-0588, For Comment (December 1979), have been referred by the Joint Intervenors in the above captioned proceeding as the new information relevant to this contention. 5. The applicant s environmental qualification program identified all Diablo Canyon Nuclear Power Plant (DCNPP) safety-related equipment for which environmental qualification is required. A complete listing is included in Tables 3. 11-1, 3. 11-1A, and 3. 11-2 fo the FSAR. 6. The incorrect inference that all safety-related equipment for which environ- mental qualification is required was apparently'drawn from the enclosure to the NRC November 2, '1979 letter which states, in part: "The FSAR Tables that identify the o erational re ui rements of equipment which must function during and subsequent to the design basis accident are general and are. not sufficiently complete for purposes of documenting 1' ' ." q p «I o h ddd). In its November 2, 1979 letter, the Staff was asking the applicant for information about "operational requirements" and "parameters" with respect to DCNPP safety-related electrical equipment in furtherance of the resolution of a generic matter. The program has been going on for some time, since approximately 1971. 7. The applicant's environmental qualification program did not ~formall evaluate the effect of aging on the ability of equipment to perform its safety functions since the Diablo Canyon qualification program was carried out in conformance with the 1971 version of IEEE 323 which does not require conslperation of aging effects. 8. The applicant's qualification program, however, did include (as established by staff review) the effects of aging to the extent that such requirements had evolved 'as a result of the continuous efforts expended by the NRC and industry with respect to the Staff's program with respect to the generic issue of environmental qualification and aging. of safety-related electrical equipment. 9. The effects of aging and the possible need for backfi tting of aging requi-rements will be reassessed in view of any new guidance or requirements developed as a result of the ongoing programs described below (the information requested by the NRC November 2, 1979 letter will provi de a concise valid basis for this reassessment). 10. The Staff's judgment is that the natural aging that the equipment will undergo in the period prior to the reassessment of DCNPP with respect to the subject generic issue will have little effect on its capability to perform its safety- related function in a harsh environment. ll. The Staff review of the applicant's environmental qualification program established, as documented in SSER Supplement 7 and in Supplement 9 (to be published in Hay 1980}, that the effect of aging was substantially included for most of the safety-related electrical equipment subject to a design basis acci dent environment. 12. With respect to the requirements for environmental qualification of safety- related electrical equipment, aging effects were consi'dered as early as 1971 with the publication of IEEE 334-1971, "IEEE Trial Use Guide for Type Tests of Continuous Duty Class I t1otors Installed Inside the Containment of '4 I Nuclear Power Generating Stations." Aging considerations are addressed in Section 4.3.1 of this standard. The standard was endorsed (with supplementary material) by Regulatory Guide 1.40. Successive IEEE standards on environmental qualification, and their endorsing regulatory guides, all addressed aging. NRC personnel have participated directly in the preparation of all IEEE environmental qualification standards as members of the standards writing groups ~ 13. The evolution of aging requirements was the result of a progressively improved understanding within the NRC and industry of the nature of aging effects and techniques to simulate aging effects on an accelerated basis for qualification testing purposes. This under- standing has been enhanced by an extensive research program originated by NRC in 1974, as well as by experience gained in the industry with to equipment qualified in accordance with IEEE 323-1974. ''espect IEEE-323 (1974) does address aging requirements. 14. In summary, a body of knowledge on the effects of aging with respect to equipment qualification has been developed over the past (approximately) nine years. This knowledge has been recently set out in NUREG-0588 For Comment (December 1979) and other NRC documents as requirements, and clarifications of requirements, for plants that are formally comnitted to the -1974 and -1971 versions of IEEE 323. Thus, the request in the NRC staff's November 2, 1979 and February 5, 1980 letters to the applicant for an investigation to identify and address significant aging mechanisms that may exist is a natural extension of the continuing evolutionary process with respect to environmental qualification and aging mechanisms. f I -5- 15. In my opinion, the identified aging mechanisms to be addressed in the staff's continuing consideration of this matter, which are significant, may well be few in number {ifany) due to de-facto considerations of aging by NRC, the applicant, and equipment suppliers during the past several years. 16. As part of this continuing evolution of aging requirements, additional guidance is needed in the area of accelerated aging techniques used to establish a qualified life for electrical equipment and assemblies. Our Category A technical activity on equipment qualification (Task Action Plan A-24) and an NRC extensive research program being carried out at Sandia Laboratories are intended to provide additional guidance for the development of test methods and licensing review procedures on aging. These- programs will also allow us to make informal judgements regarding the effects of aging. 17. As part of the Staff's Systematic Evaluation Program (SEP), the Staff is assessing the surveillance and maintenance records of the eleven SEP plants for equipment inside and outside of containment. The assessment of these records should provide additional information on the effects of aging, since this equipment has been effectively "aged". The continuing qualification programs being carried out by industry will also further improve our understanding of the effects of aging on the qualified life of equipment. 18- Following completion of these ongoing activities -- the Task Action Plan A-24, the NRC research program, and the SEP effort -- the NRC staff intends to reconsider the need for backfitting existing nuc'lear power plants with respect to the aging requirements. At that time, the NRC staff will take appropriate steps to ensure that aging effects I -6- are further considered to the extent- necessary, in assessing the adequacy of the Class IE equipment used in Diablo Canyon plant. It is the NRC staff's judgement, however, that the natural aging that the Class IE equipment will undergo in the period prior to this reassessment will have little effect on its capability to perform safety-related functions in a harsh environment in the Diablo Canyon Nuclear Power plant. 19. The staff has concluded, for the reasons given above, that the reassessment of aging for equipment which may have to operate in a post in a post accident environment, does not pose a threat to the health and safety of the public in the near term in which this matter will be I resolved, and meets Commission requirements. The above statements and opinions are true and correct to the best of my personal knowledge and belief. Thomas G. Dunni g Subscribed and sworn to before me this day of May, 1980. t ~ /, ~ Notary Publ i c /~ M My Commission expires: THOMAS G. DUNNING PROFESSIONAL UALIFICATIONS INSTRUMENTATION AND CONTROL SYSTEMS BRANCH DIVISION OF SYSTEMS INTEGRATION I have been employed by the Nuclear Regulatory Commission since November 1976. From June 1979 to the present time, I have been a Section Leader in the Instrumentation and Controls Systems Branch, Division of Systems Integration.