ML20043D692
| ML20043D692 | |
| Person / Time | |
|---|---|
| Issue date: | 02/20/1990 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | Advisory Committee on Reactor Safeguards |
| References | |
| ACRS-2690, NUDOCS 9006110077 | |
| Download: ML20043D692 (19) | |
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[/Iff DATE' ISSUED:. 2/20/90 N
ACRS SUBCOMMITTEE MEETING
SUMMARY
/ MINUTES FOR CONTAINMENT SYSTEMS FEBRUARY 6, 1990 BETHESDA, MARYLAND PURPOSE The ACRS Subcommittee on Containment Systems held a meeting on 1
February 6,
1990 in Bethesda, Maryland.
The purpose of this meeting was to discuss the staff's proposed commission' paper and supplement to the IPE generic letter in regard to recommendations for all containment types other than BWR Mark Is.
A copy of the meeting agenda and slides from the presentation are attached.
The meeting began at 1:00 p.m.,
and adjourned at 3:45 p.m.,
and was held entirely in open session.
The principal attendees were as follows:
ATTENDEES ACRS NRC/RES D. Ward, Chairman W. Beckner I. Catton, Member L. Soffer J. Carroll, Member W. Minners W. Kerr, Member T. King C.
Siess, Member J. Ridgeley u-C. Wylie, Member J. Mitchell M.
Corradini, Consultant D. Houston, Staff REVIEW DOCUMENTS (1)
Draft SECY for the Commissioners from J.
Taylor, EDO, dated February 5, 1990.
Subject:
Recommendations of Containment Performance Improvement Program for Plants with Mark II, Mark III, Ice Conderser, and Dry Containments.
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Containment Systems Minutes 2
February 6, 1990 (2)
Draft Supplement No. X to Generic Letter No. 88-20, dated February 5,
- 1990,
Subject:
Completion of Containment Performance Improvement Program and Forwarding of Insights for Use in the Individual Plant Examination for Severe Accident Vulnerabilities.
(Note:
Both of the above documents were received just prior to the start of the meeting and both were revisions-of documents provided on January 3, 1990).
ACTIONS. AGREEMENTS. AND COMMITMENTS l
(1)
The staff agreed to improve the clarity of the above docu-ments.
(2)
The Subcommittee agreed to discuss this matter at the. March 8-10, 1990 ACRS Meeting and provide comments on the recommen-dat ions.
DISCUSSION In his opening remarks, D.
Ward reviewed the ACRS activities in regard to the recommendations that the staff had proposed for BWR Mark Is.
The ACRS had indicated in their report that these i
containment improvements should be studied and pursued as part of the Individual Plant Examination (IPE) program.
For the most part, l
the Commission accepted this position and informed the staff to make this part of the IPE.
On the issue of hardened vents, the Commission directed the staff to implement this modification on all Mark I plants, handling on a backfit basis for those plants not willing to voluntarily pursue.
Mr. Ward stated that it is his belief that the staff will also purpose recommendations for other containment types within the scope of the IPE.
He indicated that due to the timing of the staff's submittal, Committee action on this mattcr would not be probable before the March 8-10, 1990 meeting.
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- Containment Systems Minutes 3
February 6, 1990 W.
Beckner (RES) reviewed the past activities of the containment performance improvement (CPI) program in regard to the BWR Mark I recommendations and discussed the proposed recommendations for Mark II, Mark III, ice condenser and large dry containments.
The i
recommendations are expected to be considered in the IPE process 1
and were stated briefly as fol]ows:
Mark II
- venting and alternate ways to cool suppression pool, Mark 1 improvements.
Mark III
- backup power to hydrogen igniters, Mark I j
improvements.
Ice Condenser - backup power to hydrogen igniters.
Large Drys
- hydrogen detonation (screening method).
W.
Beckner indicated that the above recommendations would be provided to the licensees in the proposed supplement to Generic Letter 88-20 without the benefit of technical reports under T
development at contractor laboratories.
The reports apparently will be ready about the same time as the issuance of the supple-ment.
He further indicated that the proposed supplement would be issued for information only and would contain no new requirements.
He stated that with the issuance of the supplement, the CPI program would be completed.
During the discussion, the Subcommittee members and consultant expressed various comments and concerns as follows (random order):
(1)
W.
Kerr questioned the usefulness of the contractor reports since the staff portrayed them as... " represent only potential reference material and not implied guidance."
He asked if
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7 3-Containmer.t Systems Minutes 4
February 6, 1990
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they provide no guidance, why issue them to tSe licensee.
W.
Beckner indicated that the licensee might t ^. m to use the reports in a negative manner.
(2)
J. Carroll and I. Catton expressed concerns about the lack of.
details associated with the discussion in the proposed supplement in regard to hydrogen issues.
They did not believe that stratification of hydrogen was handled adequately.- They asked why the staff had not considered referencing the National Research Council
- report,
" Technical Aspects of.
Hydrogen Control and Combustion in Severe Light-Water Reactor Accidents."
During this discussion, it became. apparent that the staff's proposed recommendations for hydrogen detonation in Large Dry PWRs was grossly deficient and lacking in clarity.
The staff agreed to revise this section of the proposed supplement. The staf f also indicated that resolution of GSI A-48 and the proposed resolution of GSI A-121 will close the hydrogen issue.
(3)
M. Corradini expressed a concern about the list of recommenda-tions and the perceived response by the licensee to them.
Specifically, he was concerned that the licensees would only focus on these highlighted issues and tend to-ignore others-of equal importance.
He asked the staff why it was tha't only these few recommendations were listed.
(4)
W.
Kerr asked how proposed containment improvements were evaluated.
W. Beckner indicated that evaluation was performed on the basis of risk.
However, he stated that no actuel risk calculations had bean performed, only a qualitative judgement had been made.
(5)
M. Corradini asked the staff about analyses or references in
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Containment Systems Minutes 5
February 6, 1990 regard to the benefits or drasbecks of. water addition to BWR drywells during an accident.
The staff felt that it would be l
beneficial after vessel failure, but not before.
- However, they could not recall any analyses or references on which to base that belief.
In fact, it was indicated that such a discussion might be in the forthcoming contractor reports.
(6)
W.
Kerr.' expressed a concern about the use of NUREG-1150: in-this study of containment improvements.
Specifically, he had reason to believe that the NUREG-1150 treatment was inap-propriate in a couple of situations, such as:
(a) for the assessment of Event V (bypass) at Sequoyah, the applied source term was assumed to be that from Surry, and (b) accident 1
progression sequences were truncated at the end of one day, therefore, challenges to containment beyond that time were not i
evaluated. The staff indicated that they would look into this matter.
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FUTURE ACTION The staff is currently awaiting feedback from CRGR in regard to the proposed documents.
Within the next.few weeks, the staff will further revise the documents to incorporate all comments provided to date.
The final revision of their proposed SECY and supplement to GL 88-20 is expected to be discussed at the March-8-10, 1990 ACRS meeting.
Commlctee comments will be provided at that time.
Note:
Additional meeting details can be obtained from a transcript of this meeting available in the NRC Public l
Document Room, 2120 L Street, N.W.,
Washington, D.C.-
20006, (202) 634-3273, or can be purchased from Ann Riley and Associates, Ltd., 1612 K Street, N.W.,
Suite 300, Washington, D.C.
20006, (202) 293-3950.
l' ACRS SUBCOMMITTEE MEETING CONTAINMENT SYSTEMS FEBRUARY 6, 1990 BETHESDA, MARYLAND
- TENTATIVE AGENDA -
C0NTAINMFt:T PERFORMANCE IMPROVFMENTS PROGRAM A.
Subcommittee Chairman Remarks D. Ward 1:00 p.m.
B.
Staff Presentetion on CPI W. Beckner/
1:15 p.m.
Program L. Soffer (RES)
++++ BREAK ""
2:30-2:45 p.m.
C.
Continuation of Discussion 2:45 p.m.
D.
Concluding Remerks and Plans D. Ward 3:30 p.m.
for ACPS heport E.
Adjournment 4:00 p.m.
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RECOMMENDATIONS OF THE CONTAINMENT PERFORMANCE
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IMPROVEMENT PROGRAM FOR PLANTS WITH MARK H, MARK HI, ICE CONDENSER, AND DRY CONTAINMENTS l
i PRESENTED TO I
ACRS SUBCOMMIlotEE FEBRUARY 6,1990 i
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WILLIAM BECKNER, CHIEF SEVERE ACCIDENT ISSUES BRANCH i
OFFICE OF NUCLEAR REGULATORY RESEARCH 1
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i PURPOSE OF BRIEFING i
TO REQUEST ACRS REVIEW AND COMMENT ON FINAL l
RECOMMENDATIONS OF THE CONTAINMENT i
PERFORMANCE IMPROVEMENT PROGRAM (CPI) FOR ALL l
CONTAINMENT TYPES OTHER THAN MARK L i
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SPECIFICALLY, REVIEW AND COMMENT ON A COMMISSION PAPER AND DRAFT GENERIC LETTER THAT WOULD REQUEST LICENSEES TO EVALUATE. SPECIFIC l
IMPROVEMENTS AS PART OF THE INDIMDUAL PLANT EXAMINATION (IPE).
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OBJECTIVES OF PROPOSED GENERIC LETTER l
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INDICATE THE COMPLETION OF THE CPI PROGRAM:
NO FURTHER REQUIREMENTS RESULTING FROM l
THIS PROGRAM AND LICENSEES CAN PROCEED WITH THEIR IPEs.
i INDICATE CERTAIN CONTAINMENT VULNERABILITIES AND POTENTIAL IMPROVEMENTS THAT THE STAFF BELIEVES COULD BE IMPORTANT AND WOULD BE EXPECTED TO BE CONSIDERED IN THE IPE.
LET UTILITIES KNOW ABOUT FORTHCOMING CONTRACTOR REPORTS DOCUMENTING THE WORK PERFORMED UNDER THE CPI PROGRAM THAT COULD BE USEFUL AS INSIGHT / TECHNICAL REFERENCE MATERIAL.
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STATUS UPDATE OFFICE CONCURRENCE (RES, NRR, AND OGC) OBTAINED ON PROPOSED PAPER AND GENERIC LF,TTER ON 1/3/99 l
AND PROVIDED TO ACRS AND CRGR FOR REVIEW.
l CRGR REVIEWED THE PACKAGE ON 1/25/90.
CRGR AGREED WITH THE SUBSTANCE OF THE PACKAGF, BUT RECOMMENDED CHANGES TO THE WORDING OF THE GENERIC LETTER TO MORE CLEARLY REFLECT THE OBJECTIVES. SPECIFICALLY - MAKE IT CLEAR THAT NO ADDITIONAL REQUIREMENTS ARE CONTAINED IN THE LETTER AND TO ENSURE THAT FORTHCOMING i
CONTRACTOR REPORTS REPRESENT ONLY POTENTIAL REFERENCE MATERIAL AND NOT IMPLIED GUIDANCE.
AGREED WITH THE CRGR RECOMMENDATIONS AND l
WILL PROVIDE REVISED WORDING TO CRGR AND ACRS.
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l CRGR DID NOT REQUEST ANOTHER MEETING.
i PLAN TO HAVE PAPER REFLECTING CRGR AND ANY ACRS COMMENTS TO THE EDO BY THE END OF MARCH.
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BACKGROUND i
i THE STAFF PRESENTED RECOMMENDATIONS FOR MARK i
I CONTAINMENT IMPROVEMENTS TO THE COMMISSION IN SECY-89-017.
RECOMMENDATIONS INCLUDED:
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HARDENED VENT ALTERNATE WATER TO CONTAINMENT AND l
VESSEL ADS IMPROVEMENTS IMPROVED PROCEDURES (EPG REVISION 4) l ACCELERATE STAFF ACTIONS ON SBO RULE
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RECOMMENDATIONS WERE BACKED BY DETAILED COST-BENEFIT AND REGULATURY ANALYSES.
ACRS STRONGLY RECOMMENDED THAT THE STAFF l
RECOMMENDED IMPROVEMENTS BE EVALUATED ON A j
l PLANT-SPECIFIC BASIS AS PART OF THE IPE.
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7 BACKGROUND (CONT.)
COMMISSION DIRECTED THE STAFF TO IMPLEMENT THE HARDENED VENT THROUGH PLANT-SPECIFIC BACKFITS FOR ALL PLANTS NOT VOLUNTARILY MAKING THIS IMPROVEMENT.
OTHER IMPROVEMENTS WERE TO BE FURTHER EVALUATED AS PART OF THE IPE.
STAFF INITIATED IMPLEMENTATION OF THE HARDENED VENT THROUGH GL-89-16 (9/1/89).
PLANT-SPECIFIC REGULATORY ANALYSES FOR PLANTS NOT
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VOLUNTEERING AND A DRAFT ENVIRONMENTAL ASSESSMENT COMPLETED.
REQUEST TO EVALUATE OTHER MARK I IMPROVEMENTS AS A PART OF THE IPE TRANSMITTED IN SUPPLEMENT 1 TO IPE GL-88-20 (8/29/89).
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j APPROACH FOR OTHER CONTAINMENT TYPES
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CPI PROGRAM APPROACH FOR OTHER CONTAINMENT i
TYPES HAS BEEN CHANGED FROM THE MARK I EFFORT:
REDUCED EMPHASIS ON DETAILED COST-BENEFIT TO JUSTIFY SPECIFIC GENERIC REQUIREMENTS.
DIRECTED PRIMARILY TOWARD INSIGHTS ON f
CONTAINMENT VULNERABILITIES AND POTENTIAL IMPROVEMENTS THAT MAY PROVE BENEFICIAL WHEN EVALUATED ON A PLANT-SPECIFIC BASIS AS l
PART OF THE IPE.
i THIS REVISED APPROACH WAS BASED ON:
NO IMPROVEMENTS THAT WOULD BE OBVIOUSLY j
COST-BENEFICIAL ON A GENERIC BASIS.
DIRECTION OF THE COMMISSION AND ACRS
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l RECOMMENDATIONS REGARDING THE l
RECOMMENDED MARK I IMPROVEMENTS.
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APPROACH FOR OTHER CONTAINMENT TYPES (CONT.)
i SPECIFIC TECHNICAL WORK PERFORMED:
I REVIEW /
SUMMARY
OF EXISTING PRA INSIGHTS.
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LIMITED SIMPLIFIED CONTAINMENT EVENT TREES EVALUATING IMPACT OF IMPROVEMENTS.
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SUPPLEMENTARY CONTAINMENT CALCULATIONS l
l EVALUATING CONTAINMENT RESPONSFlIMPACT OF IMPROVEMENTS.
.VERY LIMITED, QUALITATIVE COST ANALYSIS i
BASED ON EXISTING INFORMATION.
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CPI PROGRAM RECOMMENDATIONS FOR OTHER CONTAINMENTS NO GENERIC REQUIREMENTS TO BE RECOMMENDED.
l VULNERABILITIES AND ASSOCIATED IMPROVEMENTS THAT THE STAFF BELIEVES SHOULD BE EVALUATED ON A PLANT-SPECIFIC BASIS AS PART OF THE IPE FOR EACH CONTAINMENT TYPE HAVE BEEN IDENTIFIED.
A SUPPLEMENT TO THE IPE GENERIC LETTER WOULD BE, ISSUED PROVIDING THIS INFORMATION, CONSISTENT WITH WHAT WAS DONE FOR MARK I RECOMMENDATIONS.
i TECHNICAL REPORTS FROM THE CPI PROGRAM WILL f
BE MADE AVAILABLE TO LICENSEES TO SERVE AS INSIGHTS AND TO ASSIST IN EVALUATION OF l
VULNERABILITIES AND PDTENTIAL JMPROVEMENTS.
NO ACTION TAKEN ON OTHER CONTAINMENT VULNERABILITIES DUE TO ONGOING RESEARCH (EG.,
SARP STUDYING DCH AND DEPRESSURIZATION).
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VULNERABILITIES / IMPROVEMENTS. RECOMMENDED FOR CONSIDERAIION IN THE IPE MARK H_
VENTING AND ALTERNATE WAYS TO COOL SUPPRESSION POOL.
MARK I IMPROVEMENTS.
MARK IH BACKUP POWER TO H IGNITERS.
2 MARK I IMPROVEMENTS.
ICE CONDENSER -
BACKUP POWER TO Hz IGNITERS.
DRY CONTAINMENT -
H DETONATION (NUREG-1150 2
SCREENING METHOD
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SUGGFJTED).
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PLANNED CPI PROGRAM TECHNICAL REPORTS (NUREG/CR) 4 4
MARK H MARK III ICE DRY 1
CHARACTERIZATION INEL INEL BNL BNL I
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COMBINED COMBINED REPORT REPORT
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ENHANCEMENTS INEL INEL INEL INEL I
PARAMETRICS ORNL-COMBINED-ORNL SNL SNL t
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IMPACT OF REVISED APPROACH ON IPE i!
THE IMPACT OF THE REVISED CPI APPROACH IS THAT THE BURDEN j
OF DETERMINING THE NEED FOR CERTAIN CONTAINMENT IMPROVEMENTS HAS BEEN PLACED ON THE LICENSEE, CONSISTENT l
WITH OTHER ASPECTS OF THE IPE PROCESS.
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THIS WILL PLACE A GREATER BURDEN ON THE STAFF TO RNVIEW i
THESE ISSUES ON A PLANT-SPECIFIC BASIS.
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THIS INFOltMATION NEEDS TO BE COMMUNICATED TO LICENSEES QUICKLY SINCE THE IPE PROCESS HAS ALREADY STARTED.
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