ML20196L477

Summary of 880602 Meeting W/Numarc & EPRI to Discuss External Events Issues.Nrc Formed External Events Steering Group to Establish Methods Suitable for Examining Plants for Severe Accidents within Context of External Hazards.W/Encls

ML20196L477
Person / Time
Issue date:	06/24/1988
From:	Shao L Office of Nuclear Reactor Regulation
To:	Arlotto G, Novak T, Sheron B NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD), NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES)
References
NUDOCS 8807070517
Download: ML20196L477 (16)

Text

_ _ _

f'

• ,p %'o rd$

E "g

UNITED STATES NUCL EAR REGUI.ATORY COMMISSION n

g

-t WASHINGTON, D. C. 20555 k.... p JUN 2 4 1988 MEMORANDUM FOR:

G. A. arlotto, Member, EESG, RES T. A. Novak, Member, EESG, AE0D B. Sheron, Member EESG, RES W. Minners, Deputy Director Division of Reactor and Plant Systems, RES FROM:

L. C. Shao, Lhairman, EESG, NRR

SUMMARY

OF MEETING WITH NUMARC AND EPRI ON EXTERNAL EVENTS On June 2,1988 the EESG met with representatives of the Nuclear Utilities Management and Resources Council (NUMARC) and the Electric Power Research Institute (EPRI) to discuss external event issues. provides the list of attendees, Enclosure 2 provides the meeting agenda and the Enclosure 3 contains materials presented by various speakers.

The meeting started with my opening remarks indicating that the staff has formed the External Events Steering Group (EESG) in order to establish methods that are suitable for examining individual plants for severe accidents within the context of external hazards.

The staff provided handout material (see Enclosure 3) showing the membership of EESG and its three subcommittees.

The meeting agenda was followed in an informal way and the issues were discussed in a question and answer format. Mr. W. Rasin of NUMARC pointed out that the IDCOR program (Industry Degraded Core Program) deliberately excluded external events and he felt that seismic hazard is the only area where a significant arount of work has been done by both the industry and the staff. Mr. Rasin indicated that NUMARC has formed the Severe Accident Working Group (SAWG) under the direction of Mr. Cordell Reed to continue the integration of the industry efforts to deal with severe acciaents, and to continue the coordination with the staff as a follow on to the IDCOR effort.

NUMARC is also in the process of establishing the Seismic Working Group f SWG).

External hazards such as fire, flood and extreme wind will be reviewed by SAWG and Seismic hazard will be reviewed by SWG of MUMARC respectively. We explored how the industry intends to address accident management and establish a balance between accident prevention and mitigation. Mr. Rasin psinteo out that the accident management question goes beyond the severe accident policy, but NUMARC is in agreement with the staff on the need to work on the accident management issues and would work with the staff to bring them to a resolution; however, the industry effort would be concentrated on cost-effective plant fixes that improve plant safety.

8807070517 880624 PDR ORQ NRRBPDR f

I

' There was much discussion about fire hazard.

Dr. J. T. Chen, NRC, point'ed out that based on past PRA studies, fire hazard was shown to have freq0ently contributed significantly to the core damage frequency. Mr. Rasin expressed his disagreement with the results of the fire scoping study performed for NRC by the Sandia National Laboratories. We encouraged more studies by the industry on fire vulnerability and indicated that simplified methods for fire hazard may have to be developed.

Each of the three subcomittee chairmen under the NRC EESG briefly discussed the rtatus of his progress. Mr. Begchi distributed copies of handout material on external event issues and the plan for resolution (see Enclosure 3).

The meeting was adjourned with the following commitments from NUMARC:

(1) A letter will be sent to NRC by the end of June,1988 to info *m NRC staff the formation and charter of NUMARC working groups, (2) NUMARC will review SECY-88-14, "Integration Plan For Closure of Severe Accident issues."

(3) NUMARC will propose a meeting with the office directors of Nuclear Reactor Regulation and Nuclear Regulatory Research in July, 1988.

L. C. Shao, Chairman, EESG, NRR

Enclosures:

List of Attendees : Meeting Agenda : Meeting handouts Membership of EESG and Subcomittees by L. C. Shao External Event Issues by G. Bagchi cc:

See Distribution

.Public Docket Room Central File l

O

.DISTRIBUl!0N T. Murley, NRR W. Rasin, NUMARC J. Sniezek, NRR G. Vine, NUMARC (EPRI REP)

E. Beckjord, RES D. Rubio, EPRI D. Ross, RES F. Rahn, EPRI E. Jordan, AE0D L. C. Shao, NRR G._A. Arlotto, RES B. Sheron, RES T. M. Novak, AE00 W. Minners, RES W. Houston, RES C. McCracken, NRR F. Coffman, RES C. Thomas, NRR T. Cox, NRR R. Barrett, NRR F. Hebdon, NRR W. Schwink, NRR J. E. Richardson, NRR A. Thadani, NRR G. Bagchi, NRR A. Murphy, RES W. Beckner, RES D. C. Jeng, NRR L. Reiter, NRR N. Chokshi, RES J. Chen, RES N. Anderson, RES J. Flack, RES D. Notley, NRR A. El-Bassioni, NRR G. Wiseman, Rll A. Datta, RES B. Hardin, RES J. Strosnider, RI R. Wescott, OSP K. Campe, NRR T. Cheng OSP K. Manoly, NRR

ENCLOSURE 1 MEETING WITH NUMARC/EPRI list of Attendees Names Affiliation GBagchi NRC/NRR W. Minners NRC/RES William Beckne NRC/RES Kamal Manoly NRC/NRR Jim Richardson NRC/NRR Nilesh Chokshi NRC/RES John T. Chen NRC/RES David C. Jeng NRC/ DEST David P. Notley NRR/ECEB Leon Reiter NRR/ESGB

~

Andrew J. Murphy RES/DE/SSEB Don Rubio EPRI T, M. Novak NRC/AE0D/DSP Frank Rahn EPRI Larry Shao NRC/NRR Bill Rasin NUMARC Gary Vine EPRI REP TO NUMARC

t ENClasutg 2'

AGENDA FOR EESG-NUMARC/EPRI MEETING June 2, 1988 OWFN, 2:00 p.m - 4:00 p.m. Room 12B11 2:00 p.m Opening Remarks L. Shao and and EESG Purpose Other EESG Members 2:05 p.m NUMARC/EPRI Perspective NUMARC/EPRI on External Events IPEs 2:15 p.m NRC EESG Subcommittees, L. Shao/G. Bagchi-Plan and Schedule NRR Subcommittee Chairmen 2:45 p.m NUMARC/EPRI Plan NUMARC/EPRI and schedule for resolving the external event issues 4

(Earthquakes, Fires, Flood, High Wind, Transportation) 3:45 p.m Action items and Future G. Bagchi/NUMARC/EPRI Meeting (s) i

..,-,7

-y,_,,,__,m.._.-__,.-r,-._.,,..r.

ENCLOS/MG ),

y 1

NRC EXTERNAL EVENTS STEERING GROUP MEMBERSHIP

. CHAIRMAN:

L. C. SHA0 NRR f

MEMBERS:

G. ARLOTTO RES T. NOVAK

- AE0D B. SHERON RES EXECUTIVE G. BAGCHI NRR SECRETARY:

I 1

i l

4 1

- ew r-

-<-,t-,,y,--e-4,wr~-

em--v3-,,r--.%m-yy,e

>.-gp--,

,w,wm.,,m--y

,,,,gy-vy w,avw wr w-r, e-v p

---,-mmg-,

y y

v ye.4-m* y wr--w e-

EXTERNAL EVENTS STEERING GROUP SUBCOMMITTEES SEISMIC SUBCOMMITTEE:

C0-CHAIRMAN:

A. MURPHY RES C0-CHAIRMAN:

L. REITER NRR MEMBERS:

D. JENG NRR N. CH0KSHI RES J. CHEN RES N. ANDERSON RES G. BAGCHI NRR FIRES SUBCOMMITTEE:

CHAIRMAN:

C. MCCRACKEN NRR MEMBERS:

J. FLACK RES D, NOTLEY NRR A. EL-BASS 10NI NRR G. WISEMAN Ril A

DATTA RES J. CHEN RES B. HARDIN RES HIGH WIND, FLOOD AND OTHERS SUBCOMMITTEE:

C0-CHAIRMAN:

D. JENG NRR C0-CHAIRMAN:

W. BECKNER RES MEMBERS:

T CHENG OSP J. STROSNIDER (RI)

J. CHEN RES R. WESCOTT OSP K. CAMPE NRR i

~ _ _

e l

i MEETING WITli NUMARC 8 EPRI ON EXTERNAL EVENTS i

GOUTAM BAGCHI, CHIEF STRUCTURAL AND GEOSCIEi1CES BRANCH, NRR AND EXECUTIVE SECRETARY, EXTERNAL EVENTS STEERING GROUP JUNE 2, 1988

'1 1

6 i

l l

1 i

i i

i l

1

[

EXTERNAL EVENT ISSUES MANY POSSIBLE SOURCES OF HAZARD SOME MORE IMPORTANT THAN OTHERS OFTEN LARGE UNCERTAINTIES IN ESTIMATING FREQUENCY OF RARE EVENTS CONSENSUS DOESN'T EXIST ON USING PROBABillSTIC METHODS FOR SOME EVENTS NATURAL HAZARD DESIGN CRITERIA MAY BE OUT-0F-DATE NRC HAS DIFFERENT PROGRAMS ADDRESSING DIFFERENT DESIGN AND BEYOND DESIGN BASIS EVENTS NEED TO DETERMINE PROPER MIX OF PROBABILISTIC AND DETERMINISTIC APPROACH FOR DIFFERENT HAZARDS IN SEVERE ACCIDENT POLICY / IMPLEMENTATION NEED FOR INTEGRATION AND/0R COORDINATION WITH EXISTING PROGRAMS

..,=

EARTHOUAKES ISSUE

• UNCERTAINTIES IN SEISMIC HAZARD AND CHANGING DESIGN PROCEDURES HAVE LED TO SEVERAL PROGRAMS TO ADDRESS DIFFERENT ASPECTS OF DESIGN AND BEYOND DESIGN BASIS EARTHOUAKES PROPOSED TASKS

• ASSESS - INDIVIDUAL PROGRAMS (E.G. A-45, A-46, SEIS-MIC DESIGN MARGINS, CHARLESTON EARTHQUAKE) IN LIGHT OF SEVERE ACCIDENT POLICY

• DEFINE PROBABILISTIC/ DETERMINISTIC MIX OF SEVERE ACCIDENT SEISMIC POLICY

• DEFINE SEVERE ACCIDENT POLICY IMPLEMENTATION MAKING OPTIMAL USE OF EXISTING PROGRAMS AND MINIMlZING OVERLAP SCHEDULE

• C0ORDINATED EARTHQUAKE POLICY AND DEFINE SEVERE ACCI-DENT !MPLEMENTATION METHOD IN 18 MONTHS

INTERNAL FIRES ISSUE BASED ON THE RESULTS FROM MORE THAN 10 PRAs,

• INTERNAL FIRES CONTRIBUTE BETWEEN 10% AND 60% OF CORE MELT PROBABillTY, RESULTS ARE PLANT SPECIFIC (1.E. A DUPLICATE UNIT CAN HAVE A DIFFERENT PROBABILITY),

EARLY CONTAINMENT FAILURE SEQUENCES DUE TO FIRE ARE LIMITED,

• FIRE RISK SCOPING STUDY INDICATES THAT PLANT SPECIFIC ISSUES MAY RESULT IN HIGHER CORE MELT PROBABILITIES THAN SHOWN BY CURRENT PRAs PROPOSED TASK

• IDENTIFY LEAD PLANT AND CONDUCT A STAFF EVALVATION OF THEIR FULL SCOPE FIRE PRA METHODOLOGY (STAFF REVIEW IN PROGRESS FOR BRUNSWICK)

- MEET WITH INDUSTRY GROUPS

- PROVIDE STAFF APPROVAL FOR FULL SCOPE FIRE PRA METHODOLOGY

• INTEGRATE RESULTS OF ONG0ING FIRE RISK SCOPING STUDY

{

• EVALUATE INDUSTRY PROPOSALS

• DEVELOP IPE METHOD FOR EVALUATING INTERNAL FIRE INITIATED ACCIDENTS SCHEDULE t

• DEVELOP DRAFT IPE METHODOLOGY IN 16 MONTHS AND FINAL l

METHODOLOGY IN 24 MONTHS

EXTERNAL FLOODS ISSUE UNCERTAINTY AND LACK OF CONSENSUS WITH RESPECT TO PROBABILISTIC DESCRIPTION OF EXTREME FLOOD HAZARD, NRC CRITERIA ARE DETERMINISTIC PROPOSED TASKS DETERMINE FEASIBILITY OF DEVELOPING PROBABillSTIC EXTREME FLOOD HAZARD USING PROBABILISTIC APPROACH (IF AVAILABLE) OR ALTER-NATE DETERMINSTIC METHODS TO DEFINE METHODOLOGY FOR DEAL-ING WITH EXTERNAL FLOOD INDUCED SEVERE ACCIDENTS l

FIND PLANT SPECIFIC VULNERABILITIES i

SCHEDULE PANEL REPORT WITHIN 6 MONTHS SEVERE ACCIDENT METHODOLOGY,WITH:N 18 MONTHS

HIGH WIND AND TORNAD0ES SOURCES OF POTENTIAL HIGH WIND / TORNADO DAMAGE:

DIRECT DAMAGE DUE TO DYNAMIC WIND LOADING TORNADO MISSILES ATMOSPHERIC PRESSURE CHANGE TORNAD0ES MAY OCCUR PRACTICALLY ANYWHERE IN'U.S.

BUT OCCUR MORE FREQUENTLY IN THE EAST i

HIGH WIND STORMS MAY ALSO OCCUR ANYWHERE IN U.S.

J

'l

\\

1

OFFSITE POWER LOSS OR HIGH PROBABILITY OF FAILURE WIND DAMAGE OF STACKS, IF PRESENT, MAY JEOPARDIZE THE PLANT

~

OUTD0OR TANKS ARE SUSCEPTIBLE TO WIND DAMAGE NONSAFETY GRADE STRUCTURES OR COMPONENiS MAY CONTROL PLANT

RESPONSE

4 4

TORNAD0ES AND HIGH WINDS SHOULD BE CONSIDERED AMONG THE-EXTERNAL HAZARDS TO NUCLEAR POWER PLANTS IT IS POSSIBLE TO SEPARATE THE PROBABILISTIC ANALYSIS OF THE INITIATING EVENT (HIGH WIND /TORNAD0) FROM THE PROBABILISTIC ANALYSIS OF THE PLANT RESPONSE TO THE INITIATING EVENT ABOUT ONE-HALF THE PLANTS WILL HAVE TO ASSESS VULNERABILITIES TO THE WIND AND TORNADO HAZARD

PLAN OF ATTACK THE FOLLOWING STEPS WILL BE FOLLOWED TO DEVELOP A COMPREHENSIVE REPORT:

CLEAR-CUT DEFINITION OF SUBTASKS AND G0ALS COMPILATION OF A BACKGROUND DOCUMENT COVERING STATUS, G0ALS AND FINDINGS OF ONG0ING PROGRAMS INTEGRATION OF ONG0ING EFFORTS BY INDUSTRY AND NATIONAL LABS RELATED TO EXTERNAL EVENTS PROPER USE OF DETERMINISTIC AND/0R PROBABILISTIC CRITERIA ESTABLISH INTERFACE WITH INDUSTRY FOR A BETTER UNDERSTANDING OF ISSUES UTILIZATION OF CONSULTANTS WITH STAFF EFFORT IN THE TECHNICAL MANAGEMENT OF THE PROGRAM

)

i

_.,. _ _.