ML20057E255
| ML20057E255 | |
| Person / Time | |
|---|---|
| Issue date: | 08/11/1993 |
| From: | Rogers K NRC COMMISSION (OCM) |
| To: | Taylor J NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO) |
| Shared Package | |
| ML20057E254 | List: |
| References | |
| NUDOCS 9310080181 | |
| Download: ML20057E255 (1) | |
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UNITED STATES l'
NUCLEAR REGULATORY COMMISSION n
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August 11, 1993 MEMORANDUM FOR:
James M. Taylor Executive Director for Operations FROM:
Kenneth C. Rogers h,
Commissioner
SUBJECT:
SECY-93-190, REGULATORY APPROACH TO SHUTDOWN l
AND LOW-POWER OPERATIONS 1
i The subject SECY Information_ paper presents an evaluation of i
risks associated with low-power-and shutdown operations, together with various safety enhancements that would ameliorate these risks.
It is my understanding that the staff proposes development of a prescriptive rule to implement'these enhancements.
l While a new regulation' addressing _ shutdown issues might include-programmatic improvements that could increase safety, other regulatory possibilities exist, but are not' discussed in detail l
in SECY-93-190, for example, a performance-based rule.
A l
legitimate question can be raised as to whether for a given type of reactor, undesirable or unallowable regimes of equipment and system unavailability could be established from risk-based l
L analyses, permitting consideration of a performance-based as opposed to a prescriptive approach.
i i
Licensees might, for example, be required to maintain in an l
operable state those SSCs which PRA analyses had' indicated were needed to prevent one or more regimes which would result lin unacceptable increases in Core Damage Function (CDF) given i
l further single or multiple SSC failures.
One possible approach might be to require each licensca to demonstrate to the staff-
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with an acceptable risk-based model (PRA) that the outage configuration it proposes would not result in an. increase in the l
CDF by more than some acceptable differential frequency per L
reactor year, such as 1E-05/r-y.
L JLs part of the staff's on-going assessments:of shutdown and low-L
' power _ safety, I request that the possibility of one or more options to a prescriptive rule, including a performance-based-rule or a generic letter which would request voluntary adoption of a proposed staff position, be evaluated'in advance of
-l development of the final policy paper and its submittal to the Commission.
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gent cc:
The Chairman Commissioner Remick i
. Commissioner de Plangue i
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