ML20212H704
| ML20212H704 | |
| Person / Time | |
|---|---|
| Issue date: | 06/05/1999 |
| From: | Shirley Ann Jackson, The Chairman NRC COMMISSION (OCM) |
| To: | Diaz N NRC COMMISSION (OCM) |
| Shared Package | |
| ML20212H698 | List: |
| References | |
| SECY-98-300-C, SECY-99-133-C, NUDOCS 9906280079 | |
| Download: ML20212H704 (2) | |
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June 3,1999 COMNJD-99-003 Commissioner Disapproved. See attached coments.
MEMORANDUM TO:
Chairman Jackson Commissioner Dicus Commissioner McGaffigan hh Commissioner Merrifield Shirley Ahn JacVson 6/05/99 FROM:
Nils J. Diaz
SUBJECT:
ADDITIONAL CONSIDERATIONS FOR RESOLUTION OF SECY-98-300 AND SECY-99-133 The Commission has been moving toward resolution of SECY-98-300 and is now considering SECY-99-133. I would be remiss if I did not ask my fellow Commissioners to consider several issues that arise as a result of recent comments and directional changes regarding modification of the maintenance rule. In particular, I believe the Commission needs additional evaluation of proposed changes to 10 CFR 50.65(a)(4) and their potentialimplication for adequate protection and/or backfit findings.
From its letters of April 14 and May 11,1999, the ACRS appears to be expressing concern with combinations of multiple low risk-significant safety systems, structures, and components (SSCs)
'and their impact on plant safety during maintenance, and, presumably, when they fail. In its letter of April 14,1999, the ACRS stated that "[i]t is not apparent that components ranked as having low safety significance will continue to be of low safety significance under all the configurations that can occur when multiple components are simultaneously taken out of service." It further stated, in its letter of May 11, that "[a] different configuration or a different mode of operation may change the relative rankings of the SSCs." On plain reading, this would cppear to create an open+nded requirement.
The ACRS seems to be raising questions involving maintenance configurations and/or failure of SSCs, including the adequacy of PRAs to characterize accident sequences, that could be viewed as having implications for adequate protection. Some might construe the ACRS concems as making it necessary to re-evaluate established NRC policies to consider out-of-service and/or failures of all low risk-significant SSCs, and all combinations of low and high risk-significant SSCs. For instance, what is the acceptable variability in risk level associated with different configurations or modes that will not trigger consideration of adequate protection?
I continue to believe that technical specifications, Appendices A and 8 of Part 50, the design basis, and risk-informed additions thereto, provide reasonable assurance of adequate protection. However, in light of the ACRS findings suggesting the need for evaluation of the risk-significance of all actual configurations before performing maintenance, I recommend that the ACRS promptly evaluate the potential implications of its conclusions for determinations of f
9906280079 9906M PDR Cortf8 #ECC CORRESPONDENCE PDR
a ga Chairman Jackson's Comments on COMNJD-99-003 l
I disapprove of the recommendations by Commissioner Diaz because these concems already have been addressed by the staff in the final revision to SEGY 99-133 dated May 17,1999. The recommendation for further ACRS review is not warranted because the specific ACRS concerns have already been evaluated and resolved by the staff as noted in the ACRS letters. If there are any residual concems on these matters, I am confident that the staff can readily address them in developing guidance before the effective date of the final rule.
The recommendation for an OGC backfit review is likewise not warranted because: (1) the original backfit analysis has always bounded all considered versions of the assessment scope, l
and (2) the current backfit and regulatory analysis was recently revised prior to submittal of l
l While I share Commissioner Diaz's desire for an open and scrutable process, I would note that stakeholder input has been vigorously solicited throughout this rulemaking. The public l:
- Commission meeting on May 5,1999, merely is the most recent opportunity for stakeholder concerns to be raised and considered. I do not believe that another public meeting is needed l
because no new issues have arisen since the May 5 meeting and the existing issues have been 4
fully vetted during the rulemaking.
Consequently, I do not believe that the analyses and meeting recommended by Commissioner Diaz are needed and see no reason to link disposition of COMNJD-99-003 with the Commission decision on the final maintenance rule proposed by the staff in SECY 99-133.
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