ML20151D161
| ML20151D161 | |
| Person / Time | |
|---|---|
| Issue date: | 10/16/1987 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | Advisory Committee on Reactor Safeguards |
| References | |
| ACRS-2529, NUDOCS 8804130431 | |
| Download: ML20151D161 (15) | |
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DATE ISSUED:
10/16/87
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f,, n p4-.,4 ACRS Subcomittee Meeting Sumary/ Minutes for Safety Philosophy, Technology and Criteria October 7, 1987 Washington, D.C.
Purpose The ACRS Subcomittee on Safety Philosophy Technology and Criteria met on October 7, 1987 in Washington, D.C.
The purpose of this meeting was to discuss the legal definition (if any) of the minimum requirements for adeouate protection as applied to the proposed Backfit Rule and to discuss the NRC Staff's response to the ACRS recomendations of May 13, 1987 in regard to the Safety Goal Policy Implementation Plan. Copies of the agenda and selected slides from the presentations are attached. The meeting began at 6:00 p.m. and adjourned at 8:15 p.m., and was held entirely in open session.
The principal attendees were as follows:
Attendees ACRS NRC/0GC D. 01rrent, Chaiman S. Crockett W. Kerr, Member M. Malsch C. Michelson, Member F. Remick, Member NRC/RES D. Ward, Member C. Wylie, Member W. Houston R. Savio. Staff J. Murphy I
D. Houston, Staff G. Hulman i
NRC/EDO M. Taylor Discussion Two distinct topics were discussed at the Subcomittee meeting:
(1) the definition of adequate protection for safety as applied in the proposed Backfit Rule, and (2) the NRC Staff's consideration for the Safety Goal Policy Implementation Plan.
8804130431 871016 PDR ACHS PDR 2529
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SPT&C Meeting Minutes October 7, 1987 For the first topicy S. Crockett and M. Malsch (0GC) discussed the legal viewpoints on the meaning of adequate protection for safety.
In the two tiered approach for cnst benefit consideratinn, those issues necessary to secure or attain adequate protection will not be subjected to cost benefit analysis while those issues that enhance or supplement adecuate protection will be subjected to an economic analysis.
It was indicated that adequate protection for safety was used synonymously with the phrase, "without undue risk to the public." Adequate protection was not interpreted as zero risk or as "no more TMI-2s."
M. Malsch indicated that being in compliance with the Comission's Rules, Regulations and Orcers, under ordinary circumstances, would be presumed to fulfill the requirements for adequate protection but that this may not always be the case. The bottom line appeared to be:
(1) that there was no specific definition of the minimum requirements for adequate protection, (2) that the perceived definition meandered from time to time, and (3) that in many cases the definition was a judgemental call.
For the second topic, W. Houston (RES) discussed the Staff's considera-tions for revision of the Safety Goal Policy Implementation Plan. These considerations / revisions were in response to the ACRS report dated May 13, 1987. He addressed the use of safety ocals and quantitative objec-tives (surroaate targets).
He indicated that the proposed targets should be something to aim for and should not be applied by the Staff or others as a standard or requirement. Analytical results could be compared with taroets to determine a degree of confidence rather than a measure of compliance.
For each level or tier in the hierarchical structure proposed by ACRS, he discussed quantitative objectives or j
criteria for each level / tier. These objectives or criteria were pre-sented as preliminary positions and were not intended as the current NRC Staff position.
RES would use the feedback from this discussion with the Subcomittee and guidance from the Comissioners for further consid-eration in finalizing their Implementation Plan. A future Subcommittee
l SPT&C Meeting Minutes October 7, 1987 meeting in late November or C ember was anticipated to discuss the proposed final draft of the i ilementation Plan.
During the meeting Subccenn tt te members expressed concerns and opinions as follows:
Backfit Rule (1)
D. Okrent described a case at the St. Lucie plant in which the plant met the regulations but the Board found that adequate pro-tection was not provided in regard to Station Blackout.
He also asked if the Staff needs to do anything to make clearer what it thinks adequate protection means.
(2)
W. Kerr expressed an opinion that adequacy appears to be in the eye of the beholder.
He also asked about the events that would trigger a cost benefit analysis - a hearing, an intervenor or Staff review.
M. Malsch indicated such an analysis would be principally addressed by the Staff or Connission.
W. Kerr asked abcut older plants that met existing regulations when they were licensed as compared to current regulations and how this would be considered in term of backfitting.
(3)
F. Remick further discussed the matter of upgrading existing plants and asked about the case of filtered vents for containment.
Safety Goal Implementation Plan (1)
D. Ward expressed a concern that numerical results from PRAs were being down played too much. He questioned the additional conserva-tism in going from one tier to another. He discussed the defense-in-depth concept, e.g., the contairment failure probability should be 10-1 independent of core melt frequency.
He asked if the Safety Goal would be used as a frontal attack on the regulations.
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l, SPT&C Meeting Minutes October 7,1987 (2)
D. Okrent expressed dissatisfaction with the approach that targets should be a goal to strive toward rather, there should be some confidence that the goals are ma+, especially with future plants.
He questioned the proposed proce;ss toevel 3 PRA plus GSIs) as the most favorable way to obtain higher confidence for future plants.
He also discussed the is:ue of censistency within the hierarchical structure.
He further discussed some areas where the regulations are inadequate.
He indicated that the aspect of population density be given high priority for the Staff's consideration as well as land use affected by contamination.
(3)
F. Remick questioned the selection of an average individual within the one mile zone and the dose calculation for him/her.
(4)
W. Kerr questioned the interpretation of excellence in performance as a major goal. He also asked about the consideration of seismic events and whether there was more uncertainty in describing opera-tional performance or seismic risks.
W. Houston indicated the risks were far greater for operational performance than seismic.
NOTE:
Additional meeting details can be obtained from a transcript of this meeting available in the NRC Public Document Room, j
1717 H Street, N.W., Washington, D.C., or can be purchased from Heritage Reporting Corporation, 1220 L Street, N.W.,
Washington, D.C. 20005, (202) 628-4888.
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ACRS SUBCOMk..:e MEETING ON SAFETY PHILOSOPHY, TECHNOLOGY, AND CRITERIA OCTOBER 7, 1987 WASHINGTON, D.C.
- PROPOSED AGFNDA -
SPEAKER APPR0X. TIME A.
SUBCOMMITTEE CHAIRMAN'S REPARKS D. OKP.ENT 6:00 P.P.
B.
LEGAL DEFINITION OF MINIMUP PEQUIREMENTS M. MALSCH/
6:10 P.M.
AS APPLIED FOP. THE BACKFIT RULE S. CROCKETT (OGC)
C.
STAFF'S PLAN FOR SAFETY G0AL R. W. HOUSTON (RES) 6:30 P.M.
POLICY IMPLEMENTATION Address ACRS Reconnendations Options D.
SUMMARY
, CONCLUSIONS AND ACTIONS D. OKRENT 7:45 P.M.
FOR FUTURE SUFCOPJilTTEE MEETINGS E.
ADJOURN 8:00 P.M.
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CONSIDERATIONS FOR REVISION SAFETY _G0AL IMPLEMENTATION PLANS BACKGROUND S.G. POLICY STATEMENT ISSUED AUG. 1986 "STATUS" MEMO TO COMMISSION - JANUARY 2, 1987 COMMISSION BRIEFING ON STATUS - JANUARY 8, 1987 ACRS MEETINGS WITH STAFF - JANUARY - APRIL, 1987 ACRS LETTER - MAY 13, 1987 ACRS MEETING WITH COMMISSION - AUGUST 6, 1987 FURTHER COMMISSION GUIDANCE ANTICIPATED 10/07/87 1
/ SAFETY GOAL IMPLEMENTATION PL
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ACRS - 3 ELEMENT PLAN 1.
USE OF SAFETY G0ALS TO JUDGE ADEQUACY OF REGULATION NOT REGULATORY JUDGMENTS ON SPECIFIC PLANTS 2.
HIERARCHICAL STRUCTURE 3.
CONTINUATION OF PROGRAM 0F RISK ESTIMATES FOR SPECIFIC PLANTS -
l SAMPLING PROGRAM 9
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0 1nin7 /n7 7
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USE OF SAFETY G0ALS AND 0VANTITATIVE OBJECTIVES (SURROGATES) o FOCUS IS ON USE OF RISK ASSESSMENT METHODS AND TECHNIQUES, ice., PRA/PSA INFORMATION, WHEN AVAILABLE THE SAFETY SIGNIFICANCE IS MUCH MORE IN THE PROCESS THAN THE NUMERICAL RESULTS o
SAFETY G0ALS REFLECT "LEVEL OF RISKS --- THAT THE INDUSTRY SHOULD STRIVE FOR IN ITS NUCLEAR POWER PLANTS."
(COMMISSION POLICY ATEMENT)
STAFF WOULD EXPECT LICENSEES AND FUTURE APPLICANTS TO USE AS TARGETS TO AIM FOR o
STAFF USE IN REGULATORY ACTIVITIES SHOULD COMPLEMENT (NOT SUBSTITUTE FOR)
DETERMINISTIC ENGINEERING JUDGMENT ON THE ADEQUACY OF SAFETY MARGINS IN CURRENT REGULATORY PRACTICE STAFF WOULD EXPECT THE HIERARCHY OF SURROGATES TO BE VERY USEFUL IN RESOLVING SEVERE ACCIDENT ISSUES FOR LICENSED PLANTS, AND FOR FUTURE PLANT APPLICATIONS STAFF MUST ALSO RESPECT QUANTIFIED OBJECTIVES AS AIMING POINTS OR TARGETS AND NOT AS STANDARDS OR AS REQUIREMENTS QUANTITATIVE PRA RESULTS MAY BE COMPARED WITH SURROGATE TARGETS 10/07/87 3
/ SAFETY GOAL IMPLEMENTATION PL
i USE_OF_ SAFETY GOALS (CONT.)
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CURRENT LICENSED PLANTS j
I SAFETY GOAL SURROGATES SHOULD BE USEFUL TOOLS FOR EVALUATING RESULTS OF THE INDIVIDUAL PLANT EVALUATION PROGRAM (IPE) 4 o
FUTURE PLANTS SEVERE ACCIDENT POLICY STATEMENT INCORPORATES EXPECTATION OF A
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FULL PRA STAFF DOES NOT HAVE TO AGREE WITH, OR FIND ACCEPTABLE, THEIR "BOTTJM LINE" FINDINGS - BUT NEVERTHELESS CAN FIND THAT PRA METHODULOGY HAS BEEN CONSTRUCTIVELY EMPLOYED i
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SAFETY G00. HIERARCHY SH3ULD BE COR"ELATFD WITH LEVEL OF PRA INFORMATION AVAILABLE o
REFERENCE PLANT PRAs ARE USEFUL POINTS OF DEPARTURE FOR ASSESSING POTENTIAL NEEDS FOR CHANGES IN REGULATORY REQUIREMENTS In/n7/R7 4
/ SAFETY GOAL IMPLEMENTATION PL
TIER I - QUALITATIVE SAFETY GOALS o
ARTICULATED AS GENERAL GOALS FOR NUCLEAR POWER PLANT OPERATION - NOT NECESSARILY FOR EACH PLANT - NO DIRECT USE OR APPLICATION IA NO SIGNIFICANT ADDITIONAL RISK TO LIFE AND HEALTH OF INDIVIDUALS IN PR0XIMITY TO PLANTS o
CURRENT APPLICABLE REGULATION (PART 100 INDIVIDUAL DOSE GUIDELINES)
ARE COMPATIrJ.E WITH THIS G0AL o
NOTE THAT NON-FATAL INJURY (RISK TO HEALTH OTHER THAN CANCER) IS NOT CARRIED THROUGH TO THE 4 EXT LOWER TIER In
-RISK COMPARABLE TO OR LESS THAN THOSE FROM VIABLE COMPETING TECHNOLOGIES AND NO SIGNIFICANT ADDITION TO OTHER SOCIETAL RISKS o
COMPARABILITY QUESTION MAY BE A FUTURE TASK FOR THE STAFF o
SOCIETAL RISKS INTERPRETED AS CANCER FATALITIES IN NEXT LOWER TIER 10/07/87 5
/ SAFETY GOAL IMPLEMENTATION PL
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TIER II - QUANTITATIVE HEALTH OBJECTIVES 0
THIS IS THE HIGHEST LEVEL OF SURROGATE TARGETS IIA PROMPT (EARLY) FATALITY RISK TO AVERAGE PERSON WITHIN ONE MILE SHOULD NOT EXCEED 0.1% OF RISK FROM ALL OTHER CAUSES OF ACCIDENTAL DEATHS TRANSLATES TO 5.'10-7/R-Y TARGET o
IIB CANCER FATALITY RISK TO POPULATIO?: WITHIN 10 MILES SHOULD NOT EXCEED 0.1%
OF SUP GE CtJiCER FATALITY RISKS FROM ALL OTHER CAUSES TRANSLATES TO 2'10-6/R-Y TARGET o
LEVEL 3 PRA INFORMATION NEEDED FOR COMPARISIONS o
APPLICABLE TO FUTURE PLANTS - BY APPLICAN1 AND STAFF c
APPLICABLE TO CURRENT LICEWSEES ONLY IF THEY DO LEVEL 3 PRA - NOT EXPECTED ("REQUIRED *)
10/07/87 6
/ SAFETY GOAL IMPLEMENTATION PL
TIER _III - LARGE RELEASE GUIDELINE III OVERALL MEAN FREQUENCY OF A LARGE RELEASE SHOULD BE LESS THAT 10-6/R-Y CRITERIA FOR DEFINING SUCH A SURROGATE FOR TIER II o
CONSISTENCY: NOT A DEFACTO NEW POLICY o
BASIS FOR CONSISTENCY MUST BE DEMONSTRATED o
PRACTICAL AND SIMPLIFIED LESS CALCULATIONAL COMPLEXITY IN APPLICATION CURRENT STAFF CONSIDERATIONS:
o CONSISTENCY WITH TIER IIA ONLY IS PROPOSED e
SIMPLIFY BY EXCLUDING SITE RELATED FACTORS THAT HAVE NO BEARING ON
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PLANT SAFETY: 1.E., A "LARGE RELEASE" SHOULD BE DEFINED AS A RELEASE o
LEVEL 2 PRA INFORMATION NEEDED FOR COMPARISONS 10/07/87 8
/ SAFETY GOAL IMPLEMENTATION PL
TIER IV - PLANT PERFORMANCE OBJECTIVES THESE SURR0 GATES WOULD BE A DIRECT APPLICATION OF DEFENSE-IN-DEPTH PRINCIPLE ACRS RECOMMENDED OPERATIONAL PERFORMANCE OBJECTIVE OBJECTIVE IS NOT QUANTIFIABLE IN PROBABILISTIC TERMS AND EXCELLENCE IS ALREADY A MAJOR GOAL OF THE AGENCY AND THE INDUSTRY (INPO), THEREFORE NOT EXPLICITLY INCLUDED IN STAFF PLANS AS DESCRIBED HERE.
IVA ACCIDENT PREVENTION OBJECTIVE o
ACRS SUGGESTED TARGET:
10-4 MEAN CORE MELT FREQUENCY (CMF)
CORE MELT TAKEN AS LOSS OF ASSURED CORE COOLING l
o ALTERNATIVE BEING CONSIDERED BY STAFF:
A.
10-5 MEAN CMF CORE MELT TAKEN AS "CORE-0N-THE-FLOOR" B.
10-4 LOSS OF ASSURED CORE COOLING (LACC)
PLUS 10~I CORE-ON-THE-FLOOR GIVEN LACC 10/07/87 11
/ SAFETY GOAL IMPLEMENTATION PL
TIER IV (CONT'D,J CURRENT STATE-0F-THE-ART OF PRA DOES NOT MODEL CORE MELT PROGRESSION PHENOMENA TO PERMIT CALCULATION FOR COMPARISON WITH THE SECOND PART OF B.
IT MAY, HOWEVER, BE A USEFUL TARGET FOR IN-VESSEL ACCIDENT MANAGEMENT IVB.
ACCIDENT MITIGATION OBJECTIVE (CONTAINMENT PERFORMAGCEi 10-1 LARGE RELEASE GIVEN CORE-0N-THE-FLOOR LEVEL 1 PRA INFORMATION NEEDED FOR COMPARISONS WITH TIER IVA LEVEL 2 PRA INFORMATION NEEDED FOR COMPARISONS WITH TIER IVB NOTE:
THE STAFF IS CONSIDERING THE POSSIBILITY THAT ALL HIERARCHICAL TARGETS SHOULD BE APPLICABLE TO CURRENT AND FUTURE PLANTS, BUT THAT
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SUBSTANTIALLY HIGHER CONFIDENCE SHOULD BE OBTAINED FOR FUTURE PLANTS THROUGH THE.ER0 CESS OF PERFORMING FULL SCOPE LEVEL 3 PRAs AND
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ACCOMMODATING RESOLUTION OF RELEVANT GENERIC SAFETY ISSUES.
In/07/R7 12
/ SAFETY GOAL IMPLEMENTATION PL
TIER V - RULES AND REGULATORY PRACTICES (THE STAFF WILL MAKE SOME GENERAL OBSERVATIONS REGARDING THE LINKAGE AMONG SAFETY GOALS AND SURR0 GATE TARGETS, PRAs, AND THE BODY OF REGULATORY PRACTICES, INCLUDING CURRENT UNCERTAINTIES ON THE-IMPACT OF THE RECENT COURT DECISION ON THE BACKFIT RULE.)
)
10/07/87 13
/ SAFETY G0AL IMPLEMENTATION PL