ML20195J368

Summary of ACRS Subcommittee on Safety Philosphy,Technology, & Criteria 871202 Meeting in Washington,Dc Re NRC Proposed Implementation Plan for Safety Goal Policy Statement. Proposed Agenda & Viewgraphs Encl

ML20195J368
Person / Time
Issue date:	12/17/1987
From:	Advisory Committee on Reactor Safeguards
To:	Advisory Committee on Reactor Safeguards
References
ACRS-2539, NUDOCS 8801280063
Download: ML20195J368 (18)

Text

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/9.!/7[gJ ACRS SUBCOMMITTEE MEETING

SUMMARY

/ MINUTES FOR THE SAFETY PHILOSOPHY, TECHNOLOGY, AND CRITERIA DECEMBER 2, 1987 WASHINGTON, D.C.

PURPOSE The ACRS Subconmittee on Safety Philosophy, Technology, and Criteria met en December 2, 1987, in Washington, D.C. The purpose of this meeting was to continue the discussion of the NRC Staff's proposed implerzentation plan for the Safety Goal Policy Statement. Copies of the agenda and selected slides from the presentations are attached. The meeting began at 1:00 p.n. and adjourned at 5:45 p.m. and was held entirely in open session. The principal attendees were as follows:

ATTENDEES:

ACF.S NRC/RES D. Ward, Chairman W. Houston W. Kerr, Member F. Lewis, Member C. Michelson, Member NRC/ED0 D. Moeller, Member M. Taylor C. Wylie, Member D. Houston, Staff '

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DISCUSSION As background, the Staft: issued a preliminary implementation plan for the I Safety soal Policy Statement on January 2, 1987. This plan was discussed e.t numerous subcommittee meetings, and the Cormittee issued their reccrrmenda-tions en the plan in a letter dated May 13, 1987. Another subcommittee meetir.g was held on October 7, 1987, to discuss revisions to the Staff's plan. Further guidance was provided to the Staff by the Commission in a memorandum dated November 6, 1987. As ,a result,of the above documents and gginggp m2D DESIGNATED ORIGINIL

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SPTC MINUTES . December 2, 1987 discussions, the Staff made further revisions to their prop'osed implementa-tion plan and this revised plan was discussed at this meeting.

In his opening remarks, D. Ward emphasized that the ACRS had a particular responsibility in this area since the Commission had, in general, endorsed  ;

the Comittee's recommendations of May 13, 1987.

W. Houston (RES) discussed the current status of the proposed Staff implemen-tation plan for the Safety Goal. In general, he presented details on: (1) background and schedule, (2) an interpretation of the ACRS recommendations, (3) description of the hierarchal levels, (4) a brief description of a potential alternative to the hierarchy, and (5) the operating plant sampling j program. A major portion of his presentation was devoted to quantitative health objectives (QH0s) and the definition of a large release. At the request of the Comission, the Staff is preparing two option papers to be submitted, tentatively, on January 15, 1988: (1) Large Release Guidelines and (2) Plant Performance Objectives. The Staff intends to have a "final"'

revision of th.e proposed implementation plan for the Safety Goal ready by January 31, 1988. I l

During the presentation, Subcommittee members extensively discussed and questioned the Staff's approach to resolve the following issues: (1) use of safety goals to judge the adequacy of rules, regulations, and regulatory practices, (2) the quantitative health objectives, (3) the large release guidelines, (4) the performance objective based on loss of assured core cooling, and (5) the operating plant sampling plan. In, regard to adequacy of i regulations, the members expressed a concern that PRA results appear to be I applied more toward individual plant licensing actions rather than the intended applications of assessing the adequacy of regulation and rules.

Concerns were also expressed about the treatment of external initiators in these studies. The' discussion in regard to large release guidelines focused on the three alternative bases: (1) use of a reference dose which varied from 5 rem to 450 rem, (2) ground contamination level, or (3) a release t' hat

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3- December 2', 1987 resulted in one or more early fatalities. For the performance objective, the members emphasized that in their letter of May 13, 1987, they defined core melt as loss of assured core cooling which can result in severe core damage.

It was uncertain how the Staff was applying the term-core melt. The Staff indicated they did not expect to be able to quantify an operational performance objective in the near future. The members expressed some concerns about this since operational performance was considered as a major contributor in risk studies.

In closing, D. Ward indicated that the Subcommittee should meet again to discuss the revised implementation plan in late January or early February and J following that, the Committee could review the plan and provide comments in February or March 1988.

Attachments:

As stated l

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NOTE: Additional meeting details can be obtained from a transcript of thic meeting available in the NRC Public Document Room,1717 H Street, N.W., Washington, D.C., or can be purchased frem Peritage Reporting Corporation, 1220 L Street, N.W., Washington, D.C. 20555,(202) 628-4888.

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NOVEMBER 20, 1987 ACRS SUBCOMMITTEE MEETING ON SAFETY PHILOSOPHY, TECHNOLOGY, AND CRITERIA DECEMBER 2, 1987 WASHINGTON, D.C.

- PROPOSED AGENDA -

SPEAKFR APPROX. TIME A. SUBCOMMITTEE CHAIRMAN'S REMARKS D. WARD 1:00 p.m.

B. STAFF'S PLAN FOR SAFETY G0AL POLICY R. W. HOUSTON 1:15 p.m.

IMPLEMENTATION

- Address ACRS Reconnendations (May 13, 1987) ,

Address Conmission Guidance (November 6,1987)

C.

SUMMARY

, CONCLUSIONS ANC 'ONS D. WARD' 3:45 p.m..

FOR FUTURE SUBCOMMITTEE MLLIING D. ADJ0 URN 4:00 p.m.

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BACKGROUND AND SCHEDULE o SAFETY GOAL POLICY STATEMENT AUG. 1986 o PRELIMINARY STAFF IMPLEMENTATION PLAN JAN. 2, 1987 o ACRS LETTER MAY 13, 1987 O COMMISSION GUIDANCE NOV. 6, 1987

) . o OPTION PAPERS ON LARGE RELEASE GUIDELINE AND PLANT PERFORMANCE OBJECTIVES JAN; 15, 1988 0

PROPOSED REVISED IMPLEMENTATION PLAN JAN. 31, 1988 s

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' FIRST ELEMENT OF ACRS RECOMMENDATIONS VIEWED AS: .

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o C0llERENT SET OF ELEMENTS DIRECTED TOWARD RESOLVING "Il0W SAFE IS SAFE EN0 UGH?" IN A GENERIC SENSE, O SUGGESTING A "TOP DOWN" APPROACil TO NUCLEAR POWER PLANT -

REGULATION o STRIVING TOWARD RULES AND PRACTICES Tl1AT CAN BE SHOWN TO BE BOTH NECESSARY AND SUFFICIENT e

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USE OF PRA RESULTS AND SAFETY GOALS ON INDIVIDUAL PLANTS

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. o ACRS CAUTIONS AGAINST USE OF SAFETY G0ALS TO MAKE JUDGMENTS ON INDIVIDUAL PLANTS  :

o STAFF AGREES TilAT NARROWLY DIFFERENTI ATED DECISIONS BASED SOLELY ON SAFETY G0AL OBJECTIVES NOT WARRANTED o 110 WEVER, USE OF SAFETY G0AL OBJECTIVES AND PRA RESULTS CAN  !

s CONTRIBUTE TO OVERALL JUDGMENTS ABOUT SPECIFIC PLANTS: OBJECTIVES ARE I

TARGETS AND NOT REQUIREMENTS i

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THE STAFF PLANS T0:

o PLACE PRIMARY EMPHASIS ON THE USE OF PRA WHILE RECOGNIZING THERE WILL REMAIN UNQUANTIFIABLE ATTRIBUTES OF SAFETY PRACTICE OUTSIDE ITS KEN.

o LINKSU5SIDIARYOBJECTIVESTOINFORMATIONAVAILABLEFROMDIFFERENT LEVEL PRAs ACCIDENT PREVENTION - LEVEL 1 PRA .

ACCIDENT MITIGATION - LEVEL 2 PRA CONSEQUENCE MITIGATION - LEVEL 3 PRA e

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ACRS PROPOSED HIERARCHY LEVEL 1 - QUALITATIVE SAFETY G0ALS J

LEVEL 2-ObANTITATIVEilEALTHOBJECTIVES(Ol10)

LEVEL 3 - LARGE RELEASE GUIDELINE LEVEL 4 - PERFORMANCE OBJECTIVES LEVEL 5 - REGULATIONS AND REGULATORY PRACTICES .s

. LINKAGE CRITERIA 1

ACRS SUGGESTS TilAT EACH SUBORDINATE LEVEL:

c BE CONSISTENT WITH Tile LEVEL AB0VE (N0 NEW DE FACTO POLICY) o REPRESENT A SIMPLIFICATION OF TiiE PREVI0llS LEVEL o PROVIDE A BASIS FOR ASSURING SAFETY GOAL POLICY OBJECTIVES -

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LEVEL TWO - QUANTITATIVE IIEALTH OBJECTIVES (OH0) o CORRELAT.ES WITil LEVEL 3 PRA INFORMATION o EARLY FATALITY 0110 TRANSLATES TO INDIVIDUAL RISK 0F 5 10(-7)/R-Y TARGET. .

o LATENT CANCER FATALITY OHO TRANSLATES TO INDIVIDUAL RISK OF 2 -

10(-6)/R-Y TARGET .

o Ol10s FOCUS ON RISK T0 "AVERAGE" INDIVIDUALS (LOCATIONALLY) o RULES AND PRACTICES FOCUS ON MAXIMALLY EXPOSED INDIVIDUALS o OH0s DO NOT DIRECTLY REFLECT POPULATION DENSITY CONSIDERATIONS o POTENTIAL EFFECTIVENESS OF OFFSITE EMERGENCY PLANS CAN, IN PART, BE RELATED TO POPULATION DENSITY, ll0 WEVER o Sil0VLD CREDIT FOR EMERGENCY ACTIONS BE INCLUDED IN PRAs BEFORE COMPARING TO OH0s?

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s LEVEL TilREE - LARGE RELEASE GUIDELINE -

o OVERALL MEAN FREQUENCY OF A "LARGE RELEASE" -- Sil00LD BE LESS TilAN 30(-6) PER REACTOR YEAR o SIMPLIFICATION CRITERION - STAFF PROPOSES TO DEFINE TilRESHOLD VALUE OF A LARGE RELEASE IN TERMS OF EQUIVALENT AMOUNT OF A SINGLE RADIONUCLIDE, E.G., I-131 o CORRELATES WITil PRA LEVEL 2 INFORMATION .

o- CONSISTENCY WITH Oll0s NOT STRAIGHTFORWARD. PROPOSED LARGE RELEASE GUIDELINE INiiERENTLY MORE STRINGENT THAN OH0s. -

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LEVEL THREE'- Al.TERNATIVE BASES F'OR "LARGE RELEASE" ,

o USE OF A REFERENCE DOSE LD 50 10CFR100 GUIDELINE .

EN0 CRITERION PROTECTIVE ACTION GUIDE LEVEL O GROUND CONTAMINATION. LEVEL LONG TERM -

INTEGRATED DOSE OR DOSE RATE RELATION TO ENO CRITERION o TRANSLATE PREVIOUS STAFF RECOMMENDATION (0NE OR MORE EARLY FATALITIES) INTO A RELEASE O

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LEVEL THREE - CONTAINMENT PERFORMANCE OBJECTIVE o CONTAINMENT PERFORMANCE IS REFLECTED IN LEVEL 2 PRA INFORMATION o STAFF CONSIDERING, AS A MINIMim, AN OBJECTIVE FOR CONTAINMENT PERFORMANCE SUCH THAT THE OVERALL MEAN VALUE FOR THE CONDITIONAL PROBABILITY OF CONTAINMENT FAILURE GIVING RISE TO A LARGE RELEASE, GIVEN CORE-ON-THE-FLOOR, IS NOT GREATER TilAN 0.1 0 SUCH A PERFORMANCE OBJECTIVE CAN BE VIEWED AS A REASONABLE LIMIT TO A TRADEOFF BETWEEN ACCIDENT PREVENTION AND ACCIDENT MITIGATION o THERE MAY BE PARTICULAR CLASSES OF FACILITIES TO WHICil THIS MINIMUM OBJECTIVE MIGHT BE APPLIED

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, O O LEVEL F0llR - PERFORMANCE OBJECTIVES FOR ACCIDENT PREVENTION o ACCIDENT PREVENTION IS REFLECTED IN LEVEL 1 PRA INFORMATION

. o ACRS SUGGESTED TARGET 10(-11) CORE MELT FREQUENCY (CMF) ,

CORE MELT TAKEN AS LOSS OF ASSURED CORE COOLING (LACC) o ALTERNATIVES BEINGCONSIDERED BY STAFF 10-5 MEAN CMF ,

o FOR FUTURE PLANTS - CORE MELT TAKEN AS LOSS OF ASSURED CORE COOLING o FOR CURRENT PLANTS - CORE MELT TAKEN AS CORE-0N-THE-FLOOR WITH 10(-4)

AS TARGET FOR LACC, AND 10(-1) AS TARGET FOR IN-VESSEL ACCIDENT MANAGEMENT / CORE STABILIZATION -

LEVEL FOUR - OPERATIONAL PERFORMANCE

o. THE STAFF DOES NOT EXPECT TO BE ABLE TO OUANTIFY AN OPERATIONAL PERFORMANCE OBJECTIVE IN TiiE FORSEEABLE FUluRE, THEREFORE, DOES NOT EXPECT TO INCLUDE AN OPERATING PERFORMANCE OBJECTIVE IN .

ITS REVISED SAFETY GOAL IMPLEMENTATION PLAN 9

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OPERATING PLANT SAMPLING PROGRAM i

o NUREG-1150 5 CONTAINMENT TYPES

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4 e 'h POTENTIAL ALTERNATIVE TO THE HIERARCHY SAFETY G0ALS_

PERFORMANCE OBJECTIVES Q

ACCIDENT PREVENTION ACCIDENT MITIGATION CONSEQUENCE MITIGATION

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PRA LEVEL 1 PRA LEVEL 2 PRA LEVEL 3 .

RULES AND REGULATORY PRACTICES

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