ML20133M174

Requests Briefing During Wk of 790319 on Listed Points Re Events Leading to Shutdown of Four Nuclear Plants

ML20133M174
Person / Time
Issue date:	03/14/1979
From:	Ahearne J NRC COMMISSION (OCM)
To:	NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO)
Shared Package
ML20133M133	List: IA-85-301, Forwards Draft Temporary Instruction Providing Guidance for Inspecting & Evaluating Licensee & CP Holder Responses to IE Bulletin 79-14, Seismic Analysis for As-Built.... Comments Requested by 790723.Supporting Documentation Encl ML20133M130 ML20133M162 ML20133M174 ML20133M190 ML20133M211 ML20133M223 ML20133M232 ML20133M247 ML20133M261 ML20133M293 ML20133M428 ML20133M451 ML20133M483 ML20133M505 ML20133M523 ML20133M555 ML20133M575 ML20133M607 ML20133M621 ML20133M635 ML20133M646 ML20133M662 ML20133M685 ML20133M699 ML20133M722 ML20133M737 ML20133M757 ML20133M771 ML20133M786 ML20133M842 ML20133M853 ML20133M891 ML20133M908 ML20133M919 ML20133M959 ML20133M996 ML20133N121 ML20133N130 ML20133N148 ML20133N166 ML20133N203 ML20133N381 ML20133N390 ML20133N407 ML20133N418 ML20133N421 ML20133N434 ML20133N440
References
FOIA-85-301 NUDOCS 8508130034
Download: ML20133M174 (1)

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A NUCLEAR REGULATOR ( COMMISSION'~*

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COY hSSIO*lER MEMORANDUM FOR: Executive Director for Operations FROM: John-Ahearne MA

SUBJECT:

EARTHQUAKE' CALCULATIONS As a follow on to the recent_ events leading up. to the shut down of four nuclear plants, I would appreciate receiving a briefing covering the following points:

How do we determine design basis for earthquakes? ,

- What degree of conservatism is employed? For example, why do we use (if we do) an earthquake that is not likely to occur except once in every 10,000 to 1 million years?

- What amount of conservatism is incorporated into our earth-quake design criteria? .

To the extent possible, describe the design basis earthquakes involved in the design requirements for the plants recently shut down.

I would appreciate receiving this briefing during the week of March 19.

cc: Chairman Hendrie Commissioner Gilinsky Commissioner Kennedy Commissioney Bradford Mr. Chilk V OPE 8508130034 e50703 ), ~

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