ML20085L968
| ML20085L968 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 06/20/1995 |
| From: | Denton R BALTIMORE GAS & ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-91-18, IEIN-95-009, IEIN-95-9, NUDOCS 9506280758 | |
| Download: ML20085L968 (2) | |
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Rostrr E. Dewrom Baltimore Gas and Electric Company Vice Presiderat Calvert Cliffs Nuclear Power Plant
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Nuclear Energy 1650 Calven Cliffs Parkway Lusby, Maryland 20657 410 586-2200 Ext.4455 local 410 260-4455 Baltimore l
June 20,1995 1
I U. S. Nuclear Regulatory Commission Washington, DC 20555 ATTENTION:
Document Control Desk l
SUBJECT:
Calvert Cliffs Nuclear Power Plant Unit Nos.1 & 2; Docket Nos. 50-317 & 50-318 Comments on NRC Information Notice 95-09: Use of Inappropriate Guidelines and Criteria for Nuclear Pinine and Pipp Support Evaluation and Design
REFERENCE:
(a)
EPRI Report TR-101968, " Guidelines and Criteria for Nuclear Piping and Support Evaluation and Design" Information Notice (IN) 95-09 establishes an NRC staff position stating that use of analytical methods other than those contained in Generic Letter (GL) 91-18 for piping and pipe supports is inappropriate because they have not been reviewed and approved by the appropriate NRC technical staff. In raising this issue, the IN highlights what appears to Baltimore Gas and Electric Company as an inconsistency between the underlying philosophy of GL 91-18 and the specific language ofits Section 6.13.
In all of its other sections, GL 91-18 establishes the principle that in determining the operability of degraded Technical Specification systems, structures and components (SSCs), a licensee is to evaluate the safety function of the SSC and determine whether there is sufficient confidence that the function will be achieved. Specific methods are not prescribed, and the licensee is responsible to determine whether the SSC is operable, Conversely, in Section 6.13 " Piping and Pipe Supports Requirements," the GL changes philosophy and directs licensees to consider SSCs operable only if the specific methods of ASME Code (Appendix F of Section III) yield a successful result. When other methods are used, Section 6.13 directs that an SSC should not be considered operable until the NRC has approved the alternate method regardless of whether it provides a high confidence that the SSC will perform its specified safety function. Not only is Section 6.13 inconsistent with the overall approach of the GL, it also places a licensee at substantial risk of an unnecessary plant shutdown even for conditions where a strong engineering basis for continued operation may have been established.
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Document Control Desk June 20,1995 Pape 2 i
With regard to the specific points contained in IN 95-09, we understand that the staff has not reviewed and approved the methodology described in Reference (a). Further, we understand that Section 6.13 allows provisions of Appendix F of Section III of the ASME Code to be used to provide evaluation criteria for temporary piping conditions which do not meet full Code requirements. Appendix F contains design rules that 'hre intended to assure that violation of the pressure retaining boundary will not occur, but are not intended to assure operability of components either during or following the specified event." We understand 10 CFR 50.55a authorizes use of suitable Code Cases to permanently resolve conditions not in conformance with the Code. However, it remains unclear to us why Section 6.13 of GL 91-18 restricts licensees solely to the use of those few pre-approved methods for temporary acceptance of degraded and nonconforming conditions. For cases where a licensee has established the requisite confidence that the SSC will perform its specified safety function, it would appear that the definition of operability in their Technical Specifications is met without advance review and approval by NRC staff. While IN 95-09 addresses the specific methodology of Reference (a), the underlying generic issue is whether licensees should have the ability to use technicallyjustifiable methods not yet considered by the Code conunittees and the NRC staff. From Baltimore Gas and Electric Company's perspective, it would appear that the guidance of Section 6.13 of GL 91-18 should be revised to permit such use.
Should you have questions regarding this matter, we will be pleased to discuss them with you.
Very truly yours, h
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RED /JM0/ dim i
cc:
D. A. Brune, Esquire J. E. Silberg, Esquire L. B. Marsh, NRC i
D. G. Mcdonald, Jr., NRC T. T. Martin, NRC P. R. Wilson, NRC R. I. McLean, DNR J. H. Walter, PSC