ML20137R191
| ML20137R191 | |
| Person / Time | |
|---|---|
| Issue date: | 04/03/1997 |
| From: | Ross D Committee To Review Generic Requirements |
| To: | Callan L NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO) |
| Shared Package | |
| ML20013B099 | List: |
| References | |
| NUDOCS 9704140061 | |
| Download: ML20137R191 (5) | |
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1 UNITED STATES r
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NUCLEAR REGULATORY COMMISSION
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WASHINGTON, D.C. 20eeH001
\\*****f April 3, 1997 MEMORANDUM T0:
L. Joseph Callan Executive Director for Operations FROM:
Denwood F. Ross, Jr.. Chairman
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I Committee to Review Generic Requirements
SUBJECT:
COMBINED MINUTES OF CRGR MEETING NUMBER 302 (Part I) and 303 The Committee to Review Generic Requirements (CRGR) met on Tuesday.
February 25. 1997. from 9:00 a.m. to 12:00 p.m. for CRGR Meeting No. 302, and on March 11, 1997, from 9:00 a.m. to 3:45 p.m. for CRGR Meeting No. 303 A list of attendees for the two meetings is provided in Attachment 1-A and 1-B, respectively.
At the 302nd CRGR meeting R. Jones (NRR), M. Cunningham (RER) and T. King (RES) presented for CRGR review and endorsement the general regulatory guide (DG-1061) and the associated Standard Review Plan (SRP) for the risk-based regulation. At the 303rd CRGR meeting. G. Holahan (NRR) and the staff presented for CRGR review and endorsement the appendices associated with the general regulatory guide, as well as the application-specific regulatory guides and the accompanying application-specific Standard Review Plans.
These combined minutes of the CRGR Meeting No. 302 (Part I) and of the CRGR i
Meeting No. 303 contain details only on the CRGR review of the general and the application-specifc risk-informed regulatory guides and the associated Standard Review Plans. Also at the 302nd CRGR meeting R. Jones (NRR).
J. Kudrick (NRR) and R. Lobel (NRR) presented for the CRGR review and endorsement the proposed generic letter on " Potential for Degradation of Emergency Core Cooling System Recirculation due to Construction Deficiencies and Foreign Material in the Containment Following a Loss-of-Coolant Accident."
1 Part II of the minutes of CRGR Meeting No. 302, containing the details on this topic, were issued on April 3, 1997.
Previously, the Committee had the benefit of a briefing on the risk-informed guidance documents at the CRGR Meeting No. 294 on October 28, 1996.
On 4
November 12, 19 and 26, 1996, at the CRGR Meetings No. 295, 296 and 297.
respectively, the staff presented for the CRGR review the earlier versions of the general regulatory guide (DG-1061) and the accompanyina SRP the regulatory guide and companion-SRP on Inservice Testing (DG-1062), and the regulatory guide on Graded QA (DG-1064): no SRP exists for Graded QA.
During-these reviews, the Committee provided extensive comments to the staff. The e
i versions presented'for CRGR review and endorsement at the CRGR Meetings 302 hT4' /
V and 303 on February 25 and March 11, 1997, respectively, were substantial i
rewrites from those earlier reviewed by the Committee.
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L. Joseph Callan The CRGR commented on the extensive inter-office cooperative effort which was evident in the development of the general and the application-specific regulatory guides and the associated Standard Review Plans.
The Committee commended the various office staff that had demonstrated a well-coordinated concerted effort in developing the extensive guidance for the industry and the staff on a complex subject within the realm of the PRA Implementation Plan for risk-informed regulation.
During the meetings, the CRGR made extensive comments on the specific documents to make an overall improvement in these documents.
Broadly speaking, the Committee made the following general observations and recommended that the staff include them in the Commission paper:
1.
Fundamental Approach The CRGR observed that these documents represented a measured ste) along the path towards risk-informed regulation.
The CRGR recognizes tlat the allowable increases in risk are small.
Thus, the approach proposed is essentially risk neutral within the error bands involved.
This is especially relevant in that based on IPE submittals a number of reactors already exceed the subsidiary core damage frequency objective of IE-4.
2.
Backfit Situation The CRGR has the responsibility to review and recommend to the ED0 approval or disapproval of requirements of staff positions to be im)osed by the NRC staff on one or more classes of power reactors.
It is t1e CRGR's urderstanding that these Regulatory Guides and the accompanying Standard Review Plans are not being imposed (i.e., there is no intent to backfit these provisions).
The CRGR did not review any application or justification under 50.109, as none was tendered to us.
3.
Value Added Role The Commission has encouraged the CRGR to continue to exercise a value-added role (that is, above and beyond its strict Charter role) in its review.
Accordingly, the CRGR offers the following opinions:
a.
Use of Small Numbers The CRGR observed that, in some applications of the general regulatory guide there would be utilization of small numbers, in the PSA space.
For example, if a plant had a core damage frequency (CDF) in the vicinity of IE-4/yr. there could be a limiting increase in CDF in the range of IE-5 to 1E-6.
Under the proposed new guidance, an increase in v
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L. Joseph Callan CDF would be limited to 1E-6 under normal conditions: or, with increased technical and management review, an increase of 1E-5 might be permitted.
In the limiting case, therefore. (i.e.. in the near vicinity of CDF =
1E-4) CDF could increase from 9.8 to 9.9 x E-5 without special management consideration; or, with increased technical and management review. CDF might be permitted to increase from 8.9 to 9.9 x E-5.
The Committee agrees with other experts that there is " difficulty in identifying very low frequency initiators in the range of IE-6 per year or lower."
The Committee further notes that even with the small changes in absolute value of risk, the changes that could be made to the current licensing basis of a plant may be quite significant from an economic viewpoint.
The Committee cautions on risk ranking schemes that m<1y be used to valuate the risk significance of systems and/or components - one should not base decisions on the relative order of very low probability sequences.
b.
Safety Goals DG-1061 identifies the role of the Commission's Safety Goal Policy.
In l
particular the guide states that the acceptance guidelines defined "are consistent with the Safety Goals and their subsidiary objectives and i
changes to the CLB are expected to result in changes in risk which do not exceed the goals and which are no more than a small fraction of these goals and objectives."
c.
Monitoring Program Although the Committee recognizes that monitoring is an important aspect of a performance-based risk-informed regulation approach, care should be taken not to specify the elements of a monitoring prograrr v prescri atively.
In that regard, in the proposed guidancc-documents the staff siould consider simplifying the guidance provided on monitoring.
With the understanding that indeed the risk-informed decision process is voluntary, and that viable alternates or approaches remain available to the regulated industry, the CRGR has no objection to these documents going forward.
In accordance with the ED0's July 18. 1983 directive concerning " Feedback and Closure of CRGR Review," a written response is required from the cognizant office to report agreement or disagreement with the CRGR recommendations in these minutes. The response is to be forwarded to the CRGR Chairman and if there is disagreement with the CRGR recomendations, to the EDO for decision making.
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L. Joseph Callan
. Questions concerning these meeting minutes should be referred to either Jim
. Conran (415-1978) or Raji :Tripathi (415-7584).
' Attachments: :As stated cc:
Commission (5)
SECY.
J, Lieberman. OE E.~ Halman. ADM H. Bell, 0IG
-K.
Cyr, DGC J. Larkins.'ACRS Office Directors
. Regional Administrators. RI/RII/RIII/RIV CRGR Members G. Holahan, NRR-W. Hodges, RES Distribution of Minutes for CRGR Meetinas 302 (Part II) and 303 See next page Document Name: S:\\CRGR\\DMTS 02.303
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Distribution'of-Minutes for CRGR Meetinas 302 (Part II) and 303
- Central File w/att PDR (NRC/CRGR) w/o att.
CRGR SF
E.' Jordan.
J. Mitchell R. Tripathi J. Conran i
~ A. Thadani
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M..Cunningham J. Rosenthal G. Milman-A. El Bassioni D, Fischer B. Hardin.
R.' Woods R. Jones
' T. King W. Hodges i
J. Miller S, Black i
S. Dinsmore' J.' Flack i
A. Ramey-Smith M. Rubin M. Wohl
' L, Srtssard R. Gramm N. Giles M. Cheok i
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