ML20133H634

Notation Vote Response Sheet,Approving W/Comments, SECY-96-128, Policy & Key Tech Issues Pertaining to W AP600 Standardized Passive Reactor Design

ML20133H634
Person / Time
Site:	05200003
Issue date:	11/15/1996
From:	Jackson, The Chairman NRC COMMISSION (OCM)
To:	Hoyle J NRC OFFICE OF THE SECRETARY (SECY)
Shared Package
ML20133H573	List: ML20133H571 ML20133H634 ML20133H654 ML20133H666 ML20133H673 ML20133H730
References
SECY-96-128-C, NUDOCS 9701170237
Download: ML20133H634 (3)

Text

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NOTATION VOTE ij RESPONSE SHEET TO: John C. Hoyle, Secretary FROM: CHAIRMAN JACKSON

SUBJECT:

SECY-96-128 - POLICY AND KEY TECHNICAL ISSUES PERTAINING TO THE WESTINGHOUSE AP600 STANDARDIZED PASSIVE REACTOR DESIGN Approved X (w/ comments) Disapproved Abstain Not Participating Request Discussion COMMENTS:

See attached comments.

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(/ SIGNATURE Release Vote /X / November 15, 1996 DATE Withhold Vote / /

Entered on "AS" Yes X No 9701170237 970115 PDR COMMS NRCC CORRESPONDENCE PDR

Chairman Jackson's Vote on SECY-96-128, " Policy and Key Technical Issues Pertaining to the Westinghouse AP600 Standardized Passive Reactor Design" For the issues approved by the Commission, OGC should include language in the design certification rulemaking which assures that ,

the level of safety associated with Commission approved positions be maintained during the life of the certification (and renewals).

Prevention vs. Mitication of severe accidents 3 .

l I approve the staff's recommended position as stated in their revised clarification paper of November 12, 1996, and as approved l by ACRS in its letter dated August 15, 1996. l Based on the uncertainties associated with the reliance on passive systems in mitigating severe accidents, and the advantages of j having operator intervention as part of the design's accident mitigation features --

additional system (s) for accident management and long term mitigation is prudent.

Approval of this position is additionally based on the staff position (as stated in the November 12, 1996 paper) that direct credit for such additional system (s) would not be granted in evaluating design basis accidents.

Additionally, I approve staf f consideration of the use of realistic passive natural fission product removal coefficients contingent upon inclusion of the additional system (s) for severe accidents.

I do not consider this an inappropriate " link" between design and severe accident criteria, because the staff is basing their consideration of more realistic removal coefficients on the fact that uncertainties regarding the performance of passive safety systems are reduced with the additional system (s).

I am discouraged that this issue could not be satisfactorily resolved between the staff and the vendor. It is apparent that the staff has used arguments for both short and long term accident mitigation to justify an additional system (s). However, I understand the staf f's reluctance to accept the larger uncertainty levels, with current state-of-the-science, for evaluating the effectiveness of natural removal processes.

Should the vendor choose to do the additional testing necessary to reduce the uncertainties associated with passive fission product removal systems (e.g., fan coolers), the staff should continue its independent assessment and review of the systems.

Post-72 hour actions I approve the staff's position that the site be capable of sustaining all design basis events with onsite equipment and

supplies for the long term. After 7 days, replenishment of

! consumables such as diesel fuel oil from offsite suppliers can be credited.

External Reactor Vessel Coolinc I approve the staff's position that Westinghouse use a balanced approach, involving reliance on in-vessel retention of the core complemented with limited analytical evaluation of ex-vessel phenomena, to address the adequacy of the AP600 design for ex-l vessel events.

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