ML20215L145
| ML20215L145 | |
| Person / Time | |
|---|---|
| Issue date: | 09/08/1986 |
| From: | Schrock V Advisory Committee on Reactor Safeguards |
| To: | Boehnert P, Michelson C Advisory Committee on Reactor Safeguards |
| References | |
| ACRS-CT-1858, NUDOCS 8610280494 | |
| Download: ML20215L145 (2) | |
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1 CT-/758 1
N Mr Carlyle Michelson ECCS Subcommittee. ACRS U.
S.
Nuclear Regulatory Commission e
Washington, D.
C. 20557 Sept.
8, 1986 Dear Mr Michelson.
Att'n Mr Paul Boehnert Re: 10 CFR 50.46 and Appendix K Revision My major comments on the material presented at the ECCS Subcommittee meeting on August 28, 1986 are as follows.
1.
In general the Compendium of ECCS Research for Realistic LDCA Analysis is a well prepared document in support of the licensing rule change.
This has been a major effort to prepare and the staff should be commended for their efforts.
I believe the document will be very useful in the future, during rule change and beyond.
As always some aspects of the document might have been done differently and some parts with more care and accuracy.
In this report I will comment only on those items that I consider major.
I 2.
The most important thing to consider is the fact that the Compendium together with the Draft REG Guide fail to indicate what the Regulatory staff will find satisfactory in regard to the 95%
probability.
The report acknowledges that it is not pcssible to specify a rigorous procedure for evaluation of the statistical uncertainty in the analysis results - there remains an element of
" engineering judgement" in the assessment.
In my opinion it is necessary to give clearer definition of what the regulatory standard is both to satisfy the concerns of the public and to make the rule workable for the owners.
I think the experience of dealing with the GE / GESSAR approved basis should be useful in developing some gener&l description of acceptable approaches to evaluating the 95 % confidence level from an engineering view point.
EESIO"ATED ORIGII AL 8610280494 860908 Certif'od By [Mh C - 18 pDR 1-
. g t
3.
I agree with the comment that the old Appendix K should have a finite life.
It makes no sense technically to indefinitly license plants on the basis of erroneous calculations even sehen they are known to be conservative.
This is a matter of regulatory philosophy that should be discussed by the ACRS and the Commissioners as this revision proceeds.
Since ely f
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Virgil E. Schrock Professor
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