ML20086S464

Responds to Suppl 4 to Generic Ltr 88-20, Individual Plant Exam of External Events for Severe Accident Vulnerabilities. Util Plans to Adopt EPRI Developed Fire Induced Vulnerability Evaluation Methodology

ML20086S464
Person / Time
Site:	Peach Bottom, Limerick
Issue date:	12/26/1991
From:	Helwing D PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GL-88-20, NUDOCS 9201030178
Download: ML20086S464 (7)

Text

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10 CFR 50.54 (f)

GL 88-30 Sup. 4 t-PillLADELl'lIIA ELECTRIC COMi%NY NUCLEAR GROUP HEADQUARTERS 955-65 CHESTERBROOK BIND, WAYNE. PA 19087-5691 (215) s n M 50 December 26, 1991 l

DAVID R HELWlO VCE mtSIDENT mcuAn emmtemm s semccs DockeL Nos. 50-277 50-278 50-352 50-353 License Nos. DPR-44 DPR-56 NPF-39 NPF-P5 U.

S.

Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C.

20553

SUBJECT:

Peach Bottom Atomic Power Station, Units 2 and 3 Limerick Generating Station, Units 1 and 2 Response to NRC Generic Letter 88-20 Supplement 4,

" Individual Plant Examination of External Events (IPEEE) for Severe-Accident Vulnerabilities"

Dear Sir:

NRC' Generic Letter (GL) 88-20, Supplement 4,

" Individual Plant Examination of External Events (IPEEE) for Severo Accident Vulnerabilities," dated June 28, 1991, required licensees to submit within 180 days from the issuance date of the GL a response which describes their proposed programs for completing the IPEEE.

The GL stated that the response should:

1.

identify the methods and approach selected for performing the IPEEE, 2.

describe the method to be used if it has not been l

previously submitted for staff review (the description may be by reference), and 3.

identify the milestones and schedule for performing the IPEEE, and submitting the results to the NRC.

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. December 26, 1991

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' Generic Letter 88-20 Page 2-4 Generic Letter 88-20, Supplement 4, encouraged licensees to coordinate their IPEEE seismic activities with the Unresolved Safety Issue'(USI)-A-46 issue, Seismic Qualification of-Equipment in-Operating Plants," if applicable, thereby allowing both activities to be accomplished with a single walkdown effort.

PECo agrees with the NRC and plans to coordinate its

• EEE-seismic and USI A-46~ activities so that walkdowns for each program may be combined into a single effort.

To assist us in this effort, we are awaiting the issuance of the Supplemental Safety-Evaluation Report (SSER) on the seismic-Qualitication Utility Group (SQUG) Generic Implementation Procedure (GIP), for resolution of USI A-46.

The GIP SSER, when issued, will allow PECo to finalize a coordinated plan and schedule for completion of the IPEEE seismic activities at'both PBAPS and LGS.

Because PECo plans.tc coordinate the fire and other events with our celsmic evaluations, we uould prefer not to provide an IPEEE completion schedule until after we have had an opportunity to1 review the GIP SSER.

This coordinated evaluation approach will allow.us to provide an integrated. response to GL 88-20 Supplement 4 PECo'.s response, without specific completion schedules, to GL 88-20 Supplement 4, for PPAPS,. Units 2 and 3, and LGS, Units 1 and 2, is provided as Attachments 1 and 2 to this letter respectively.

A supplemental response to this letter will be submittaa to the NRC with specific IPEEE completion schedules for both PBAPS and LGS, within 120 days after receipt of.the GIP SSER.

I If you have any questions, or require additional information, please contact-us.

Sincerely, 7dtfh Attachments cc:

T.

T. Martin, Regional Administrator, Region I J.

J.

Lyash, USNRC Senior Resident Inspector, PBAPS T. J.

Kenny, USNRC Senior Resident Inspector, LGS g

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' COMMONWEALTH OF PENNSYLVANIA Ss.

COUNTY OF CHESTER D.

R. Helwig, being first duly sworn, deposes and says:

That he t

' sins of Philadelphia Electric Company,

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' that he has read ti, >

GenGric Letter No. 88-20 Supplement 4, 4

and knows the conten.

that the statements and matters set forth therein are true an<-

t ;, t.he bost of his knowledge, information and belief.

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1 Vice Pres ent l

i Subscribed and sworn to befor,' me this ay p.

of ff('t Q,1991.

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ATTACHMENT 1 PEACH BOTIVM ATOMIC POWER S'1ATION, UNITS 2 AND 3

-RESPONSE TO GENERIC LETIER NO.;88-20, SUPPLEMENT 4

" INDIVIDUAL PLANT EXAMINATION OF EXTERNAL EVENTS (IPEEE)

FOR SEVERE ACCIDENT' VULNERABILITIES" Peach Bottom Atomic Power Station (PBAPS), Unit 2, was one of-the two-plants selected by the NRC for its study of the_ risk due to cxternal events,(NUREG/CR-4550 "Analysin of Corc-Damage Frequency: _

Peach

Bottom, Unit 2,

External Events").

The Philadelphia Electric Company (PECo) participated in this analysis by-providing design data, conducting equipment walkdowns, and-responding. to questions raised durin'g the study.

One of the options provided in.NUREG 1407, " Procedural.and Submittal. Guidance for the Individual _ Plant Examinations - of External Events (IPEEE)-

for.Severc Accident Vulnerabilitics", -for. the utility to select

~

for performing an. external event examination is to use: an existing 0

external events Probabilistic Risk Assessment- (PRA) provided the PRA reflects'the current as-built and as operated condition of the plant = and : some' of the deticiencies of past -. PRAs are adequately addressed.

-PECo hcs considered-this-option, but in-order to be able to.

demonstrate that the submittal. reflects the current as-built-and

.as-operated condition of the_ plant and to achieve the key outcomes

.of IPEEE; i.e.,_

licensee knowledge. and appropriate improvement resulting from the examination emphasized in. the Generic Letter, PECo' has decided to conduct a new external event examination.

Among.the.three.NRC-approved: methods for:the seismic evalua-tion, PECo has selected -the Electric -Power Research Institute.

-(EPRI), seismic margin assessment (SMA)' methodology. We consider.

that wo can perform an.SMA analysis--with less reliance on outside consultant ~ support, and thereby, ' PECo Engineers will. obtain the additional plant _ knowledge, emphasized by 'the ' NRC _ to - be-a 1 key outcome _ of the IPEEE._ In Laddition, SMA was-developed to ; be compatible with the USI-A-46: program which.is applicable to PBAPS.

PECo E plans to coordinato the IPEEE with the USI-A-46 review cand w ikdown.-

For-the-IPEEE fire risk evaluation, PECo plans to adopt the EP.RI ' developed '" Fire Induced Vulnerability Evaluation

(FIVE) methodology.

Our reasons for selection of the'FIVE methodology; are 'similar to our reasons for selection of SMA for the seismic

~

evaluation.

FIVE was developed to be used by the utilities' fire protection, Appendix R,

and system' engineers without extensive reliance on outside consultants.

Therefore, the use of FIVE_will enhance PECo's understanding of the risk due to fires at PBAPS.

-a-

PEco Response to GL 88-20, Supp. 4

., Page 2 For the high winds and tornadoes, external

floods, and transportation and nearby facility accidents portions of the IPEEE

analysis, PFCo will follow the screening approach detailed in Section 5.2 of NUREG 1407, "Proceduro and Submittal Guidance for the Individual Plant Examination of External Events (IPEEE) for Severo Accident Vulnerabilition."

Documentation and reporting will follow the guidance provided

'in Section B and Appendix C of NUREG 140'i.

Generic Letter 88-20, supplement 4,

requests licensocs to describe their proposed programs for completing the IPEEEs by December 26, 1991.

Also, this generic letter supplement encourages coordination of-the scismic IPEEE with Unrosolved Safety Issue A-46 "so that the objectives of both activitics may be accomplished with a single walkdown ef f ort."

As stated in-the NRC SECY-91-102 " Individual Plant Examination of External Events (IPEEE) for Severo Accident Vulnerabilitics," the procedures for the scismic walkdown portion of this program are "one of the most important ingredients in the scismic IPEEE, [and) are similar to those that will be used in the implementation of Unresolved Saicty Issue USI A-46...."

PECo agrecs with NRC staff that the walkdowns of each program should be combined into a single walkdown.

PBAPS is a USI-A-46 plant and a member of the Scismic Qualification Uti'lity Group (SQUG).

Because of the similarities of the two programs, PECo intends to conduct scismic IPEEE and USI-A-46 walkdowns at the same time to avoid repetition of essentially the same work within a short time span.

However, the anticipated Supplemental Safety Evaluation Report (SSER) on the SQUG's Generic Implementation Procedure (GIP) for resolution of USI-A-46 has-not been made available in sufficient time to permit finalization of a coordinated plan for the scismic portion of the IPEEE.

Because of the delay in issuance of the SSER, and because the fire and other events portions of the IPEEE will be coordinated with the scismic evaluation, PECo will not be able to submit a firm schedule to complete the IPEEE-for PBAPS until after receipt and revicW of the SSER.

Following this review, PEco may modify its program for conducting the scismic IPEEE depending on the content of the SSER and resolution of open issues. The PBAPS IPEEE schedule will be provided within 120 days following roccipt of the GIP SSER.

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ATTACHMF2TT 2 LIMERICK GENERATING STATION, UNITS 1 & 2 RESPONSE TO GENERIC LETTER NO. 88-20, SUPPLEMENT 4

" INDIVIDUAL PLANT EXAMINATION OF EXTERNAL EVENTS (IPEEE)

FOR SEVERE ACCIDENT VULNERABILITIES" In 1981, Philadelphia Electric Company (FECo) began its examination.of the rish due to external events at the. I.imorick Generating Station (LGS).

In 1983 the external events Probabilistic Risk Assessment (PRA) was complcred and issued in the Severe Accident Risk Assessment (SARA).

This external events PRA examined the risk due to carthquakes,

fires, external

Ilooding, high

winds,

-turbine

missiles, and transportation accidents. The SARA was performed by consultants.

The SARA risk profiles were updated and reported in " Summary of Analysis to Support Response to NRC Request for Additional Information in Consi6eration of Severe Accident Mitigation Design Alternativos (SAMDA)" for the LGS Unit 2 licensing proceedings in 1989.

Generic Letter 83-20, Supplement 4,

provides the option of verifying and updating an earlier PRA for use as an IPEEE submittal. PECo considers this a viable option for LGS.

However, in order to be able to demonstrate that the LGS IPEEE submittal reflects the current as-built and as-operated condition of the plant and to better achieve the key outcome of licensco knowledge of the risks due to external events at LGS, PECo will conduct a

.now external event examination.

Among the three NRC-approved methods f or scismic evaluation, PECo has selected the Electric Power Research Institute (EPRI) scismic margin assessment (SMA) methodology.

We consider that we can perform an SMA analysis with less reliance on outside consultant support, and thereby, PECo engineers will obtain the necessary plant knowledge emphasized by the NRC to be a key.

outcome of the IPEEE.

For the IP m fire risk evaluation, PECo plans to adopt the EPRI developed

" Fire Induced Vulnerability Evaluation" (FIVE) methodology.

Our reasons for selection of the PIVE methodology are similar to the reasons for selection of SMA for scismic evaluation'.

FIVE was developed to be~used by the utilitics' fire protection and system engineers without extensive reliance on outside consultants.

Therefore, the use of the FIVE methodology will enhance PECo's understanding of the risk due to fires at LGS.

~.. - - - - _.

PECo Response to GL 88-20, supp. 4

', Page 2 For the high winds and tornadoes, external

floods, and

~

transportationEand nearby facility accidents portions of the IPEEE analysis, PECo will follow the scrocning approach detailed in Section 5.2 of NUREG 1407, " Procedural and Submittal Guidance for i

the Individual Plant Examination of External - Events (IPEEE) for Severe Accident vulnerabilitics."

l i

Documentation and reporting will follow the guidance provided in Section 8 and Appendix C of NUREG 1407.

Generic. Letter 88-20, supplement 4,

requests licensees to describe their proposed programs for completing the IPEEE by L

December 26, 1991.

As stated in the NRC SECY-91-102 " Individual Plant Examination of External Events (IPEEE) for Severo Accident Vulnerabilitics," the procedures for the scismic walkdown portion of this prcgram are "...one of the most important ingredients in the seismic IPEEE, [and) are similar.to those that will be used in the implementation of Unresolved Safety Issue (UCI)

A-46...

Although LGS is not a USI-A-46 plant, PECo intends -to use an l

approach for scismic IPEEE evaluation that is common with our Peach Bottom. Atomic Power Station'(PBAPS), a USI A-46 plant.- PECo i

agrees with the NRC that procedures developed for resolution - of j

i the USI-A-46~ be used as much as possible for the scismic IPEEE, l-which would include the necessary training for these, procedures, i

Because of the similaritics between the USI-A-46 and seismic IPEEE' programs, PEco intends to train seismic walkdown personnel

.l l

at training courses -currently being developed by the Scismic l'

Qualification Utility Group (SQUG).

However, the anticipated NRC Supplemental Safety Evaluation Report (SSER) on the SQUG's Generic l

Implementation Procedure (GIP) for resolution of USI A-46 has not been made available in sufficient time to permit finalization and scheduling of-the SQUG courses.

Because of the delay in issuance of the SSER and because the fire-and other events portions of the IPEEE will be coordinated with the seismic evaluation, ' PECo will not be able to submit a firm schedule'.to complete the IPEEE for LGS until after receipt and review of the SSER.-

Following this review, PECo may modify its program - f or conducting the seismic IPEEE depending on the content of the SSER and resolution of open issues.

The LGS.IPEEE schedule will be provided within 120 days following receipt of the-GIP ~SSER.

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