ML20056E759
| ML20056E759 | |
| Person / Time | |
|---|---|
| Issue date: | 08/12/1993 |
| From: | Palla R Office of Nuclear Reactor Regulation |
| To: | Thadani A Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 9308250147 | |
| Download: ML20056E759 (22) | |
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August 12, 1993 MEMORANDUM FOR: Ashok C. Thadani, Director Division of Systems Safety and Analysis THRU:
William D. Beckner, Chief Probabilistic Safety Assessment Brancti Division of Systems Safety and Analysis FROM:
Robert L. Palla, Jr.
Probabilistic Safety Assessment Branch Division of Systems Safety and Analysis
SUBJECT:
5UMMARY OF JULY 7, 1993 MEETING WITH NUMARC AND BWROG REGARDING ACCIDENT MANAGEMENT On July 7,1993, the NRC staff met with representatives of the Nuclear Management and Resources Council (NUMARC) and the Boiling Water Reactor Owners Group (BWROG) regarding accident management. The purpose of this meeting was to discuss two methodologies under development by the BWROG:
(1) a methodology by which utilities can assign BWROG-developed response actions to E0Ps or SAMG without taking deviations from the BWROG product, and (2) a methodology by which training and examination relative to severe accident response actions can be prioritized. This memorandum summarizes the most significant results of the meeting. A list of attendees is presented in.
A copy of the presentation materials is provided as Enclosure 2.
Following introductory remarks, F. Emerson (CP&L/BWROG) summarized the status of the BWROG Severe Accident Management Guidance (SAMG) development effort.
A contractor team is developing strategy changes to the EPGs and supporting SAMG.
The SAMG and approximately 70% of the proposed EPG changes are expected to be complete by the end of September 1993.
The remainder of the EPG changes will be finished by the end of CY 1993.
An overview of the first of the two BWROG methodologies was then presented.
The first methodology is intended for use by utilities to assign individual EPG and accident management strategies to the best location (control room or Emergency Response Organization / Technical Support Center) without the need for documenting as deviations from the BWROG products. The EPG/AMG assignment process includes a combination of deterministic, mechanistic, and probabilistic tests / criteria on which the placement of a particular action would be judged.
It was acknowle'dged that while the methodology is intended to provide a consistent approach for dispositioning EPG and accident management actions, the results obtained by applying the methodology would not necessarily be consistent.
The follcwing points were made during ensuing discussions of the EPG/AMG assignment process (see flow chart in Enclosure 2):
All existing EPGs and proposed accident management actions would be candidates for consideration in the assignment process.
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Ashok C. Thadani l the BWROG will continue to-further develop both draft methodologies
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NRC and NUMARC/BWROG will meet again in about a month to discuss further
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details of the methodologies.
i Original signed by:
l Robert L. Palla, Jr.
Probabilistic Safety Assessment Branch Division of Systems Safety and Analysis
Enclosures:
As stated l
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DISTRIBUTION.
A/M Distribution List WBeckner AEl-Bassioni RPalla l
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NAME RPall a:bw fAfl/# AEl-BasIo'nI WBeckner DATE 08/ T/93 08/g /93 08/p/93 l
OFFICIAL RECORD COPY Document Name.: JULY 7 MET i
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Ashok C. Thadani !
t the BWROG will continue to further develop both draft methodologies i
NRC and NUMARC/BWROG will meet again in about a month to discuss further i
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Robert L. Palla, Jr.
Probabilistic Safety Assessment Branch-Division of Systems Safety and Analysis
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ACCIDENT MANAGEMENT DISTRIB'fTION FOR MEETING NOTICE TMurley,12 G 18 FMiraglia, 12 G 18 i
WRussell, 12 G 18 FCongel, 10 E 2 BBoger, 10 H 5 FGillespie, 12 G 18 f
l AThadani, 8 E 2 MTaylor, 17 G 21 DMarksberry, MNBB 3206 MSolberg,12 D 22 EJordan, MNBB 3701 JRosenthal, MNBB 9715 RBarrett, 8 H 7 EBeckjord, NLS 007 i
TSpeis, NLS 007 BSheron, NLS 007 LShotkin, NLN 353 FCoffman, NLN 316 i
RJones, 8 E 23 DHouston, P 315 JKudrick, 8 0 1 RErickson, 9 H 19 DDesaulniers,10 D 24 RGallo,10 D 18 RGallo,10 D 18 WPasedag, DOE i
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Ashok C. Thadani !
the BWROG will continue to further develop both draft methodologies NRC and NUMARC/BWROG will meet again in about a month to discuss further l
details of the methodologies.
I Original signed by:
Robert L. Palla, Jr.
Probabilistic Safety Assessment Branch Division of Systems Safety and Analysis L
Enclosures:
As stated i
i l
DISTRIBUTION:
A/M Distribution List l
WBeckner AEl-Bassioni E
RPalla NRC PDR Central Files WRasin (NUMARC) i DModeen (NUMARC) i SPSB r/f l
- i EFC SPSB:DSSA:NRR SC:SPSB:DSSA
'BC:SPSB:DSSA g-ffO Lt6 NAME RPalla:bw /48 AEl-Bassioni WBeckner i
DATE 08/ T/93 08/g /93 08/p/93
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ENCLOSURE 2 BWR OWNERS' GROUP SEVERE ACCIDENT MANAGEMENT DEVELOPMENT l
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1 ROCKVILLE, MARYLAND JULY 7,1993 l
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PRELIMINARY AGENDA NRC / NUMARC / BWROG MEETING BWR SEVERE ACCIDENT MANAGEMENT Ju_ly._7aE93 1300 Introduction J. Booker (GSU) 1305 BWROG Process for Developing Generic F. Emerson (CP&L)
SAMG 1320 BWROG Process for Assigning EPG Emerson Actions to EOPs or Plant AMG
- Exampfes of Application 1335 BWROG Criteria for Prioritizing Emerson Training /Requal Responsibilities 1350 Open discussion /NRC response All 1400 Adjourn 4
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'l4 INTRODUCTION o
NRC / Industry Meeting on February 2,1993 BWROG presented conceptual proposal for limiting severe accident training / requal responsibility NRC staff agreed with concept but i
requested more def. ails o
BWROG performed internal review of severe accident management guidance development in March 1993 Found approach technically sound i
Directed Accident Management Working Group (AMWG) to develop methodology for flexibly assigning EPG info to SAMG (to reflect wide diversity of BWR accident management philosophies)
Directed AMWG to develop training / requal prioritization proposal further 1
3
INTRODUCTION I
o AMWG developed assignment methodology and prioritization proposal in April - June 1993 o
NRC / Industry Senior Management Meeting June 3,1993 BWROG requested consideration of flexible i
assignment and prioritized training concepts NRC agreed in concept NRC indicated NUREG - 1021 Rev 7 and proposed rule change should address concerns over scenario complexity Industry concerned about consistent implementt. tion of agreements on training'/
requal ti,roughout Regions NRC staff indicated further written guidance and workshops could be provided if necessary to assure consistent implementation 4
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BWROG PROCESS FOR DEVELOPING SAMG
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Contractor team developing strategy changes to EPG and supporting SAMG o
SAMG and 70 % of proposed EPG changes to be complete by September 30, 1993 o
Romaining proposed EPG changes to be finished by December 31, 1993 o
BWROG working to develop package for info sharing with NRC before September 30 BUT o
Release of major products (draft SAMG and substantial discussion of strategy changes) must await BWROG approval at first BWROG General meeting after September 30 o
In summary: release of some information possible before September 30; major info available in early November 5
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INSIGHTS U
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BMG ASSOCIATE
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WITH STRATEGIES INSIGHT i
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CURRENT REVISION OF METHODOLOGY FOR FLEXIBLE ASSIGNMENT OF EPG ACTIONS TO EOPs AND PAMG o
Methodology is generic BWROG product along with SAMG and revised EPG o
Intended to provide consistent approach for utility application of EPG o
Intended for use by utilities on individual EPG strategies (as desired) to assure best location for strategies (control room or ERO / TSC) without need for donumentiilg_as deviations o
Application not required; default is EPG as revised by BWROG o
Utility may leave strategy in EPG even if metitodology allows placement in SAMG o
Methodology enhances safety by placing strategy where accident best managed; strategy will be more likely used effectively 7
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- 7/7/93 DRAFT *
- EPG/AMG ASSIGNMENT PROCESS
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9 DETERMINISTIC Would Placing i
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Violate Design Q
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of Placing Action PROBABluSTIC Action in PAMG is EPG Action Utility YES /
Risk Significant in input PRA (!PE, IPEEE)7 1
is Risk Unacceptable?
t YES (NUMARC 91-04, 4-NRC Safety Goals)
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May Be Placed Placed in in PAMGs PSTG/EOP l
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APPLICATIONS OF FLEXIBl_E ASSIGNMENT CRITERIA o
Different plants can legitimately locate the same strategies in different locations based on plant - specific differences o
Example of apnlying design basis criterion to stopping containment floooing when the vessel flange is reached Plant A: Place in EOP because discussed in plant FSAR Plant B: May place in PAMG because it would not conflict with FSAR to do so Example of applying ERO manning criterion to o
recovery from RPV flooding Plant C: Place in EOP because TSC manning requires 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> Plant D: May place in PAMG because TSC manned in 45 minutes I
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APPLICATIONS OF FLEXIBLE ASSIGNMENT CRITERIA Example of applying probabilistic criterion to o
alternate boration:
Plant E: Place in EOP because alternate boration is risi significant in IPE and placing in PAMG would have significant risk impact Plant F: May place in PAMG because not risk significant in IPE I
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PRIORITIZATION OF TRA!NING / REQUAL
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o Basic premises:
BWR EPGs go well into severe accident space Knowledge and training requirements for BWR operators already felt to be at upper limit Training on the routine operations which, successfully performed, prevent accidents from even beginning is more important than training on severe accident scenarios Training on accident preyEnliSn in the early stages of a transient is more irnportant than training on accident mitigation once the core has been damaged Major contributors to core damage frequency are more important to train on than insignificant ones Some limitation of ERO training in. severe accidents is appropriate; suitable criteria to be coordinated with INPO guidelines 11
PRIORITIZATION OF TRAINING / REQUAL o
Proposal makes effective use of IPE insights o
EOP action may be prioritized by the importance of the IPE sequences or containment failure scenarios it appears in o
Requal responsibility for operators given appropriate safety priority o
Severe accident training for operators nol_
. eliminate _d, but given appropriate safety priority and placed in proper context with other training requirements i
o Scenario length and need for getting into muhiple branches and contingencies should be considered in examining operators on important actions i
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7/7/93 DRAFT *
- a TRAINING /REQUAL PR!ORITIZATION EOP PAMG i
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Strategy Strategy Strategy Has Low CDF or Has Moderate Has High Criten.a Criten.a CDF or CFP CDF or CFP TBD TBD CFP Impact impact impact a
lf If If If lf-Initial Trainin'g Only/
Limited Requal Full Requal Limited Training /
Full Training /
Very Limited Training /
Training /
Evaluation Evaluation Examination Examination Examination Ul CDF = Core Damage Frequency CFP = Containment Failuro Probability (2) Criteria to be coordinated with INPO training guideline development
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EXAMPLE PRIORITIZATION CRITERIA APPLICATIONS EOP Training / Rc_qua_1 Simultaneous LOOP / LOCA could be part of o
design basis but very low CDF contributor (i.e.,1E-8); therefore, teach in initial training.
only and lowest examination priority Failure of suppression pool cooling could have o
moderate CDF impact but low containment failure impact (because of time to reach high containment pressure); therefore, conduct limited training with limited requal exposure ADS depressurization on loss of high pressure o
injection could have high CDF contribution; therefore, conduct full training with full requal responsibility a
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FUTURE ACTIONS
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o NRC Staff feedback on assignment flexibility and training / requal prioritization proposals Agreement on steps for consistent o
implementation by industry and NRC Another BWROG / NRC meeting to discuss implementation details?
i Additional written guidance to Regions?
Guidance to industry in revision to NUMARC 91-04?
NRC and industry workshops?
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