ML25196A178
| ML25196A178 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 02/17/1977 |
| From: | Fraley R Advisory Committee on Reactor Safeguards |
| To: | Rusche B Office of Nuclear Reactor Regulation |
| References | |
| Download: ML25196A178 (1) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION ADVISORY COMMITTEE ON REACTOR SAFEGUARDS WASHINGTON, D. C. 20555 February 17, 1977 Benard C. Rusche, Director Office of Nuclear Reactor Regulation
SUBJECT:
ACPS REPORI' ON 'rn:E NORI'H ANNA PGJER STATIOO', UNITS 1 AND 2, DATED JANUARY 17, 1977 This memorandum is in response to your letter of January 31, 1977 con-cerning interpretation of the ACRS report of January 17, 1977 on the North Anna Power Station, Units 1 and 2. The Corranittee considered your request for clarification during the 202nd ACRS meeting. 'Ihe members discussed the bases for the Corranittee's report on the North Anna Station and the cornments noted below are reflected in the meeting minutes.
(1)
The Corranittee concurs with its consultants in the matter of the Stafford fault zone.
(2)
The Corranittee concurs in general with the recorrmendation of its consultants that a minimum safe shutdown earthquake (SSE) of 0.2g should ordinarily be utilized for new plants for which construction permit applications are submitted in the future, although the Committee believes that flexibility in this nominal floor is ap-propriate to allow for special site conditions and specific aspects of plant design for which site dependent spectra may be important or for situations where a sound and non-controversial basis exists for setting lesser criteria.
(3)
The systems to*be investigated are those required to accomplish safe shutdown of the reactors and coijtinued shutdown heat removal.
'Ihe Committee has recommended that such systems have significant margins in the event of the SSE, so that safe shutdown has a high probability of accomplishment, should a lower probability earthquake having a response spectrum somewhat-larger than that of the usual broad band spectrum over part of the frequency range occur.
Instances in which "current accepta..11ce limits" rray be exceeded in such an evaluation may be considered acceptable on a jud~n~
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cc: L. Gossick, EOO S. Olilk, SECT 1130 Execut"iv!J.~lrect~