ML20133H654
| ML20133H654 | |
| Person / Time | |
|---|---|
| Site: | 05200003 |
| Issue date: | 11/25/1996 |
| From: | Rogers K NRC COMMISSION (OCM) |
| To: | Hoyle J NRC OFFICE OF THE SECRETARY (SECY) |
| Shared Package | |
| ML20133H573 | List: |
| References | |
| SECY-96-128-C, NUDOCS 9701170244 | |
| Download: ML20133H654 (3) | |
Text
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[
NOTATION VOTE a
l RESPONSE SHEET l
TO:
John C. Hoyle, Secretary i
FROM:
COMMISSIONER ROGERS
SUBJECT:
SECY-96-128 - POLICY AND KEY TECHNICAL ISSUES PERTAINING TO THE WESTINGHOUSE AP600 i
STANDARDIZED PASSIVE REACTOR DESIGN Disapproved"g'M fMT I
9 nnLy l
Approved > y m 4 Abstain tm
- j Not Participating Request Discussion i
j COMMENTS:
S e e, 7 ; T r g c ff u E v f.%.
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s dA SIGNATU{h Release Vote
/X /
dMM e
DATE Withhold Vote
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/
Entered on "AS" Yes X
No 9701170244 970115 PDR COMMS NRCC CORRESPONDENCE PDR
1 Conanissioner Rogers' Comments on SECY-96-128 My comments are based on the SECY of June 12, 1996 and the j
CLARIFICATION MEMO from Mr. Taylor of November 12, 1996.
The staff recommendations in the November Memo give me two concerns.
Recommendation (1) should sk e clear that this recommendation "The AP 600 design should include additional system (s) for accident manaamment and long term mitigation following a severe accident" relates only to bevond desian basis accident==nmaement, and should indicate what additional systems are contemplated.
Recommendation (2) is more significantly flawed.
Staff states that " contingent upon the inclusion of additional systems for severe accidents", they will approve the use of
" realistic' passive natural fission product removal coefficients for analyzing the consequences of desian basis accidents (to meet the provisions of the propoced revisions to 10CFR Parts 50 and 100).
However, they would not give direct credit for the activation or tg6 of such additional systems in evaluating design basis accidents.
Mitigation of desian basis accidents would be accomplished solely through the use of safety related systems.
By adopting this recommendation the Commission would be acquiescing to the establishment of a regulatory link between severe accident mitigation and design basis accident mitigation.
The staff position appears to be the.t they will use " realistic" fission product remos21 coefficients in analyzing the plant capability to meet Parts 50 and 100 only if some kind of non-safety related equipment is added, which equipment would be useful only.in the advent of a beyond design basis accident.
In my opinion, the ability of the plant design to meet the regulatory requirements of a design basis accident must be demonstrable without resort to any non-safety related equipment.
The willingnesu of the staff to accept " realistic" instead of
" conservative" removal coefficients should not be based on anything other than the technical merits'of the " realistic" coefficients were coefficients.
If the use of the " realistic a
challenged the existence of non-safety related equipment in the design would be irrelevant, because the Commission has stated its policy that the staff is not to use the existence of non-safety related equipment in analyzing the capability of a design to meet Parts-50 and 100 in the event of a design basis accident.
Therefore the staff and the stake holders (Westinghouse and others) should get together and develop an agreement on what values of the removal coefficients are acceptable. This question cannot be settled by bargaining, but it might be settled through the use of expert judgements.
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2 Another issue entangled in the staff's recommandation is that by coupling a requirement for non-safety related equipment to manage a severe accident and how NRC analyses a design basis accident obscures a fundamental point. By taking this step the Commission would be entering into a new regulatory domain i.e.
est-%11shing a set of regulatory requirements for the management of Jere accidents.
This is a Policy matter for the Commission to accide, and should not be backed into through a piece meal approach.
If the commission believes that new requirements for severe accident mitigation are needed (there are nons now) it should establish a regular process for deciding what these requirements should be, i.e.
through rulemaking.
For these reasons I do not approve the staff's recommendations for the use of non-safety related systems (s) to address the uncertainties associated with passive natural fission product removable mechani.sms.
I do not believe that we should blur the distinction between design basis events and sesure accidents by crediting the operation of non-safety related equipment, even indirectly, in our evaluation of design basis accidents.
I approve the staff's position that the site be capable of sustaining all design basis events with on site equipment and supplies for the long term, with replenishment of consumables allowed after seven days.
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.
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