TXX-4610, Discusses Implementation of NRC 850605 Conditions for Use of ASME Code Case N-397 Re Alternative Method for Spectral Broadening & N-411 Re Alternative Damping Factors. Expeditious Approval for Use of Code Cases Requested
| ML20136H155 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 11/18/1985 |
| From: | Counsil W TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | Noonan V NRC - COMANCHE PEAK PROJECT (TECHNICAL REVIEW TEAM) |
| References | |
| TXX-4610, NUDOCS 8511250046 | |
| Download: ML20136H155 (5) | |
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Log # TXX-4610 TEXAS UTILITIES GENERATING COMPANY File # 10010 903.1
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F U$Uce*Sf."Si November 18, 1985 Director of Nuclear Reactor Regulation Attention: Mr. Vince S. Noonan, Director Comanche Peak Project Division of Licensing U. S. Nuclear Regulatory Commission Washington, D.C.
20555
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION DOCKET NOS. 50-445 AND 50-446 CODE CASES N-397 AND N-411 REF:
- 1) TUGC0 letter TXX-4404 from J. Beck to H. Denton, dated January 25, 1985
- 2) NRC letter from V. Noonan to M. Spence dated June 5, 1985
- 3) NRC letter from V. Noonan to W. G. Counsil, dated September 25, 1985 L
Dear Mr. Noonan:
In Reference 1, Texas Utilities Generating Company (TUGC0) requested NRC approval for the use of ASME Code Cases N-397 (alternative method for spectral broadening) and N-411 (alternative damping factors).
In Reference 2, the NRC approved the use of those Code Cases, subject to certain conditions.
The NRC also requested certain information, independent of the l
approval to use the Code Cases.
By Reference 3, the NRC indicated that it considered these requests for information also to be conditions to use those Code Cases. By this letter TUGC0 describes its position regarding the conditions presented in References 2 and 3.
Addressing the original proposed conditions first, Reference 2 enumerated six conditions for the use of Code Cases N-397 and N-411.
TUGC0 intends to implement these conditions in the following manner:
(a) All pipe stress packages to which the two Code Cases are applied will
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be identified in the FSAR. TUGC0 notes that it is considering using j
those Code Cases for both the reanalysis and requalification effort in l
Unit 1 and the as-built reconciliation for Unit 2.
(b) For each of the pipe stress packages identified in accordance with Item (a), we will designate whether the code cases were used for new analyses, reconciliation or support optimization.
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.. -(c) The Code Cases will be used only for piping systems analyzed by response spectrum methods.
(d) When the Code Cases are used, all predicted maximum displacements will be checked for adequate clearance with adjacent structures, components, and equipment (including mounted equipment).
If the use of the Code Cases results in the removal of supports, piping system stability will be appropriately evaluated.
-(e) The piping system design specifications and required design documents will be revised to reflect the use of these Code Cases.
(f) TUGC0 intends to perform analyses using these Code Cases in a manner
. generally consistent with the guidance set forth in WRC Bulletin 300,
" Technical Position on Industry Practice." Since this document is intended to be used as guidance, we do not consider application of all provisions in the Bulletin to be appropriate. We discuss the reasons for our position below.
In analyses using the subject Code Cases, TUGC0 intends to utilize an approach which is generally consistent with the standards reflected in WRC Bulletin 300. However, we feel it is inappropriate to commit to implementing each and every recommendation as though they were set design rules that are part of our licensing requirements.
In the first instance, the recommendations in the WRC Bulletin have not been uniformly adopted as NRC requirements.
In fact, the NRC Staff Piping Review Committee recognizes that the Bulletin was not intended to impose requirements, and does not tie the recommendations in the Bulletin to the use of Code Cases N-397 and N-411, although it strongly recommends the prompt endorsement of these Code Cases.
(See NUREG-1061 (April 1985), " Report of the U.S.
Nuclear Regulatory Commission Piping Review Committee; Evaluation of Seismic Design -- A Review of Seismic Design Requirements for Nuclear Power Plant Piping," Volume 5, at page 13.)
Further, by its own terms, the Bulletin provides only recommendations to assist in establishing an effective and efficient design process.
The Bulletin states (at page 19) that the recommendations and discussions therein:
"are intended to stimulate organizations to recognize...
problem areas and to address them in a manner similar to the approaches presented here. The techniques and guidelines in the following sections are not intended to be hard and fast rules.
In many cases, organizations responsible for areas discussed in this paper have procedures in place that resolve the problems."
Finally, TUGC0 notes that Comanche Peak appears to be the only facility for which the NRC Staff conditions the use of these Code Cases on " compliance" with the Bulletin. We are aware of seven other utilities at which the use of one or both of these Code' Cases has been approved and in no instance has such a condition been imposed.
, With respect to the Staff's other requests, Reference 2 set forth three topics as to which action by TUGC0 was requested. Specifically, the Staff requested that TUGC0 (1) set forth the " reasons and basis for requesting the revision to earlier design commitments," (2) review the " hearing record" to determine whether the use of these Code Cases affects earlier testimony and, in particular, the motions for summary disposition (which applicants have since requested be withdrawn), matters reviewed by Cygna and comments by the NRC's TRT, SRT, SIT and CAT, and (3) determine whether a Construction Permit amendment is necessary to reflect the use of those Code Cases. We address each of those requests below.
Regarding the first request, use of these Code Cases will serve two principal purposes. The bases for requesting their use are the same in each case. When the request was originally submitted, the primary purpose for which it was anticipated these Code Cases would be used was in the as-built reconciliation of Unit 2, which has not been completed, or in limited reanalyses performed to address certain licensing issues.
In addition, subsequent to submittal of the original request to use the Code Cases, TUGC0 decided that questions raised with respect to the design of piping systems at Comanche Peak required a comprehensive reanalyses of those systems in order to address fully those outstanding questions. As the Staff is aware, these reanalyses are being performed by Stone & Webster.
TUGC0 intends to use these Code Cases in those reanalyses.
Further, there are sound reasons for using the subject Code Cases in each of the above processes. Primarily, these Code Cases reflect the latest views on appropriate analytical methodologies for piping system analyses.
In fact, as previously noted, in April of this year the NRC Piping Review Committee recommended the immediate implementation of these Code Cases.
(Code Case N-397 has already been incorporated into Regulatory Guide 1.84 (Revision 23, September 1985)).
In addition, we anticipate that the implementation of the two Code Cases will provide more realistic response spectra.
In summary, TUGC0 considers the above facts to provide ample justification for utilizing the Code Cases at Comanche Peak.
With regard to the request that TUGC0 review the hearing record to determine the effect of using these Code Cases, if any, on either past testimony, matters reviewed by Cygna or comments from various NRC inspection teams, TUGC0 interprets the Staff's request to concern whether it will be appropriate to rely on past record evidence to support findings before the Licensing Board regarding the adequacy of the plant in view of the possible use of new design assumptions in the above activities.
TUGC0 shares this concern. Accordingly, we set forth below a suggested approach for resolving this concern.
TUGC0 intends to address outstanding issues relating to piping and support design which have arisen from external sources, including those identified by the Staff in Reference 2, through the CPRT Program. As reflected in Applicants' Management Plan (filed on June 28, 1985, with the Licensing Board (see pages 59-60), TUGC0 intends to rely on the results of that i
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. program, not prior testimony, to resolve those issues. This renders the suggested review of the hearing record unnecessary for issues yet to be resolved.
With regard to issues previously resolved, TUGC0 is cognizant of its responsibility to inform the Licensing Board of information which constitutes a material change or development with respect to information relied upon in resolving those issues. We are also aware of our similar obligation to the Staff with respect to information previously provided to the S ta"f.
TUGC0 will fulfill these obligations if such information is identified. Further, TUGC0 intends to provide full disclosure of the results of its ongoing reinspection and reevaluation program. Thus, to the extent those results are at all relevant to issues before the Staff or the Licensing Board they will be fully apprised of their existence and content.
In addition, it would be impractical to ascertain the specific impact of individual revised design assumptions on prior analyses, or past testimony based on those analyses. As you know, TUGCO's reanalysis program includes a comprehensive plan to address, among other matters, outstanding issues concerning piping and support design. For a variety of reasons several design assumptions in that program may differ from those in the original analyses. Because of the interactions between various design assumptions, it would be impractical to determine not only the precise effect of individual assumptions on the final results of the reanalyses, but also their relationship to previous analyses on which prior testimony would have been based. Even assuming this could be done, however, it would not be possible to assess the impact on any prior analyses (and, therefore, testimony based on those analyses) until after new analyses are performed rather than prior to performing those analyses as apparently envisioned by the Staff.
Finally, it should be recognized that there are, of course, facts already in the record (e.g., general background information) which will not be affected by ongoing analyses and may be relied on in making future findings.
It is not possible to anticipate now, however, which particular facts may fall into this category. Of course, this will be a matter for consideration in the context of the hearing process.
With respect to the question as to whether approval to use these Code Cases requires an amendment to the Construction Permits for Comanche Peak, we conclude that it does not.
In the first instance, approval to use alternative methods to satisfy the ASME Code, pursuant to 10 CFR 50.55a(a)(3), does not involve the need to seek a Construction Permit amendment.
Indeed, the approval by the NRC Staff provides the necessary assurance that no safety issues are involved, without proceduralmeasuresassociatedwithsuchanamendment.{mposingthe In addition, based on our review of the PSAR, we conclude that the use of these Code Cases does not; (1) alter the principal architectural and engineering criteria 1.
See Consumers Power Company (Midland Plant, Units 1 and 2),
LBP-C2-35, 15 NRC 1060, 1972 (1982).
, for CPSES, (2) constitute a significant departure from the design bases, (3) increase the probability or consequences of previously considered accidents, (4) give rise to new accident considerations or (5) compromise or eliminate any major feature or component which can be described as a safety system. The use of these Code Cases will allow the application of seismic analyses which are applied in a more realistic and reasonable manner.
In sum, the bases for issuance of the Construction Permit are not altered, and an amendment to the Construction Permit is unnecessary.
(See 10 CFR 50.34(a)(3), 50.35(a)).2 TUGC0 requests that the Staff expeditiously consider this response. TUGC0 will have occasion to use these Code Cases in the near future.
If the 1
Staff believes that a meeting would be helpful, TUGC0 is available at the Staff's earliest convenience.
Very truly yours,
/
W. G. Counsil BSO/grr 2.
TUGC0 also notes that the best of their knowledge the NRC Staff has not requested that a Construction Permit amendment be obtained for other facilities that have obtained approval to use either or both of these Code Cases, i
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