ML20212H735
| ML20212H735 | |
| Person / Time | |
|---|---|
| Issue date: | 06/16/1999 |
| From: | Merrifield J NRC COMMISSION (OCM) |
| To: | Diaz N NRC COMMISSION (OCM) |
| Shared Package | |
| ML20212H698 | List: |
| References | |
| SECY-98-300-C, SECY-99-133-C, NUDOCS 9906280091 | |
| Download: ML20212H735 (2) | |
Text
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NUCLEAR REGULATORY COMMISSION WASHINGTON, D.c. 20555 g
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Juv 1,1999 COMNJD-99-003 Commissioner 15 of._, k affa MEMORANDUM TO:
Chairman JacksE Commissioner Dieus ommissioner McGaffigan ommissioner Merrifield
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FROM:
Nils J. Diaz
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6l16/11
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-99133. 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 tM potential implication 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 k
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 appear to create an open-ended 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 orotection. 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 B of Part 50, the design l
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 potentialimplications of its conclusions for determinations of 9906290091 990623 PDR COMMS NRCC CORRESPONDENCE PDR WO62 700 9/
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L COMMISSIONER MERRIFIELD'S COMMENTS ON COMNJD-99-003 l
As I stated in my vote on SECY-98-300, I commend Commissioner Diaz for his efforts to guide and expedite the staff's efforts to risk-inform Part 50. His insights regarding risk-informed regulation have been invaluable. In that light, I carefully reviewed COMNJD-99-003 associated l
with the Commission giving additional consideration to SECY-98-300 and SECY-99-133.
Based on my review, I continue to support the staff requirements memorandum (SRM) for SECY-98-300, which was issued on June 8,1999. Furthermore, I do not support the recommendations in COMNJD 99-003 regarding SECY-99-133. I have articulated my position on SECY-99-133 in my vote of June 2,1999 and believe that voting on SECY-99-133 should proceed without the additional analyses and public meeting requested in COMNJD-99-003.
As I stated in my vote on SECY-99-133, the final rule is a very important first ' step in making the Maintenance Rule m' ore effective and risk-informed. But clearly, this is only a first step. The staff has a great deal of work remaining on the development of regulatory guidance. I believe that the guidance development process provides the forum by which any residual concerns pertaining to the ACRS can be resolved. We should not lose sight of the fact that 1) the May.
13,1999 SRM on the Commission's May 5,1999 Maintenance Rule briefing directs that the draft regulatory guide be reviewed by the ACRS,2) the Commission will review and approve the final guidance prior to its issuance by the staff, and 3) the final rule will not become effective until the final regulatory guidance is in place. I anticipate and encourage intense Commission scrutiny of the operationalimplications of such guidance. As expressed by Commissioner l
McGaffigan, if Commissioner Diaz's concerns of an unbounded process are realized, I will disapprove the final regulatory guide and delay implementation of the rule.
With regard to the OGC backfit analysis proposed in COMNJD-99-003, I believe the backfit analysis provided in the regulatory analysis of SECY-99-133 is sufficient. It is also important to note that May 13* SRM directs CRGR review of the draft regulatory guide. Further, I anticipate that the Commission will closely scrutinize this aspect in its review of the final regulatory guidance.
I do not believe that another public meeting regarding the final rulemaking in SECY-99-133 is warranted. The staff has already solicited stakeholder input throughout the rulemaking process and a public Commission meeting was recently held on May 5,1999. Furthermore, the Commission has directed the staff to work with stakeholders in finalizing regulatory guidance through the use of public meetings and workshops, as appropriate. Having said that, given the importance of the final regulatory guidance, I believe that a public Commission briefing regarding this guidance should be conducted once it has been provided to the Commission for review and approval.
Finally, as discussed in SECY-98-300, and my vote on SECY-99-133 I believe the goal of the agency is to truly risk-inform Part 50, beginning with the scope of the idaintenance Rule. While I wish we were closer to accomplishing this goal, I believe that continued progress toward this goal may not be possible without taking the first step represented by the final rule in SECY 133. I believe it is prudent to accept the limited success this final rule represents so that the staff can move forward on the critical next steps of developing regulatory guidance and i
ultimately risk-informing the scope of the Maintenance Rule.
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