ML20086P095

Forwards Response to Generic Ltr 88-20,Suppl 4, Individual Plant Exam of External Events for Severe Accident Vulnerabilities. External Floods Will Be Addressed Using Progressive Screening Approach in NUREG-1407

ML20086P095
Person / Time
Site:	Calvert Cliffs
Issue date:	12/19/1991
From:	Creel G BALTIMORE GAS & ELECTRIC CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
RTR-NUREG-1407 GL-88-20, TAC-M74392, TAC-M74393, NUDOCS 9112260198
Download: ML20086P095 (5)

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BALTIMORE GAS AND ELECTRIC 1650 OALVERT CUFFS PARKWAY

• LUSBY, MARYLAND 20657 4702 GEORCE C. CREEL

- VICE PRES"IENT HvCLE AR Ef4ERGY (480) #e0-4 465 December 19,1991 U. S, Nuclear Regulatory Commission Washington, DC 20555

- ATTENTION: Document Control Desk

SUBJECT:

Calvert Cliffs Nuclear Power Plant Unit Nm 1 & 2; Docket Nos. 50-317 & 50-318 Generic Letter 88-20, Supplement 4, Individual Plant Examination of External Events (IPEEE) for Severe A:cident Vulnerabilities (TAC Nos. M74392: M74393)

REFERENCES:

(a) Generic Ictter 88-20, Supplement 4; Individual Fant Examination of External Events (IPEEE) for Severe Accident Vulnerabilities -

10 CFR 50.54(f)

(b) NUREG-1407; Procedural and Submittal Guidance for the Independent Plant Examination of External Events (IPEEE) for Severe Accident Vulnerabilities (c) Seismic Qualification Utility Group (SOUG) -

Generic Implementation Procedure (GIP) for Seismic Verification of Nuclear Fir ' Ecpaipment, Revision 2, dated September 1990 Gentlemen:

In accordance with Gencric Letter 88-20, Supplement 4 (Reference a), we hereby provide a

. -description of our proposed program for completing the Individual Plant Examination of External Events . (IPEEE), We have reviewed the generic letter supplement and NUREG 1407 (Reference b), and have prepared a Project Plan for performance of the IPEEE and submission of the results to the NRC. Enclosure (1) highlights our IPEEE Project Plan, including (1) identification of the methods and approach selected for performing the IPEEE, (2) description of methods to be used which have not been previously submitted for NRC staff review, and (3) identification of the milestoncs and schedule for performing the IPEEE, and submitting the results to the NRC.

As described in Enclosure 1, we are in the first year of what we are projecting to be a five-year r.ffort, culminating with a summary report in June 1996. The additional time (beyond the three-year submittal date requested by the generic letter supplement) will be necessary based upon the IPEEE Project Plan, which corciders: ,

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. Document Control Desk l December 19,1991 Page 2 o the sequencing of the IPEEE project schedule with that of the IPE to maximize resource efficiency; o the use of in-house staff to maximize BG&E's knowledge gained frorn the examination; o the resources necessary to traintain and apply the IPE to the operation and maintenance of Calvert Cliffs; o the coordination of IPEEE ith Unresolved Safety Issue (USI) A-46 and various fire -

assessments; and o the performance of this evaluation on a two-unit site, including the consideration of available outages to perform the necessary walkdowns.

. We will notify you if our plans change from what we have described in this letter and enclosure. We hope this provides you with all the information you need at this point in the process. If you need

. additional information, or if you have any questions, do not hesitate to contact us.

Very truly yours, b/.

GCC/NH/nh/ dim

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i Enclosure cc: - D. A. Brune, Esquire J. E. Silberg, Esquire -

R. A. Capra, NRC j

D. G. Mcdonald, J r., NRC

, T T. Martin, NRC l L E. Nicholson, NRC '

, R. I McLean, DNR J. H. Walter, PSC J. Butler, NUMARC i

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. ENCLOSURE (1)

Response to Generic letter 88 20

' IPEEE Project Plan

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li MI?I'IIODS AND APPROACII Generic letter 88-20 requests five external events to be assessed and an ersication of plant unique external events to be performed. He following methods will be used. ,

' l.1 = Selsmic IheM A Probabilistic Risk Assessment (PRA) approach which generally follows the techniques outlined in NUREG/CR 2300 will be developed for Calvert Cliffs Nuclear

- Power Plant (CCNPP) Unit 1 to address this event The seismic assessment for Unit 2 will only focus on its plant-unique differences relative to Unit 1 due to the

. similarities that exist between both units.-

1.2 Internal Fires Internal Fires will be assessed by developing a fire PRA for CCNPP Unit 1. It will include the analysis steps delineated in NUREG 1407, Section 4.1. Furthermore, it will use the EPRI fire events database to incorporate the most up-to-date pneric fire events information. In addition,it will adopt the FIVE fire propagation and damage assessment models for screening purposes. The fire assessment for Unit 2 will only focus on its plant-unique differences relative to ' Unit 1 due to the similarities that .

exist between both units. #

1.3 liinh Winds and Torne.tfg

-High Winds and Tora. des will be addressed usmg the progressive screening approach defined in NUREG-1407. This assessment'will address the site impact of

this external event unless unit-specific hazards are found which warrant special

= consideration.

1.4 ' External Floods External Floods will be addressed using the progressive screening approach defined -

in NURSG 1407. This assessment will address the site impact of this external event unless unit-specific hazards are found which warrant special considerstion.

1.5 - Transportation and Nearby Facility Accidents

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Transportstion and Nearby Facility Accidents will be addressed using the progressive screening approach defined in NUREG-1407. This r.ssessment will address the site

' impact of this external event unless unit-specific hazards are found which warrant special consideration.'

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. ENCLOSURE (1) t Resp <mse to Generic Letter 88 20 IPEEE Project Plan 1.6 Plant-Unique External Events External events identified in NUREG/CR 2300 will be evaluated as to their applicability to CCNPP. If any represent a unique-plant hazard to CCNPP, they will then be addressed using the progressive screening defined in NUREG 1407, Section 5. This assessment will address the site impact of thit external event unless unit specific hazards are found which warrant special consideration.

2. UNRIN1EWED MitTilODS The methods to be used by Baltimore Gas and Electric Company (BG&E) in the implementation of the Individual Plant Examination of External E"ents (IPEEE) have been previously reviewed by your staff.

3. SCIIEDUlzE AND MILESTONES As requested in the generic letter supplement, BG&E plans to use our staff to maximum extent possible in conducting the IPEEE by participating m the analysis and technical review, and by validating both the process and its results through a peer review by individuals who are not associated with the initial evaluation. It is expected that BG&E will benefit most from the IPEEE if we maximize the use of our own staff; however, it should be underr%od that this approac' will also im}.act our implementation schedule.

The generic letter supple nent also encourages coordination of the scismic IPEEE with Unresolved Safety Issue (USI) A-46 "so that the objectives of both activities may be accomplished with a single walkdown effort." As stated in NRC SECY 91-102, the procedures for the seismic walkdown portion of this program are "one of the n'est important mgredients in the seismic IPEEE, [and) are similar to ' hose that will be used in the implementation of Unresolved Safety Issue (USI) A-46. . . . . Baltimore Gas and Electric Company agrees with NRC staff that the walkdowns of each program should be combined into a single walkdown.

Calvert Cliffs is a USI A-46 plant and a member of the Sc. ..ic Qualification Utility Group (SQUG). Because of the similarities of the two progranu,30 NE intends to conduct scismic IPEEE and A-46 walkdow u 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 SCUG's Generie Imphmentation Procedw l GIP), Reference (c), for resolution of USI A-46 has not been made available in suflM:M time to permit finalization of a coordinated plan and schedule for the seismh portion of the IPEEE in this response, Baltinore Gas and Electric Company will conduct a seismic IPEEE program following a Probabilistic Risk Assessment (PRA) approach, as detailed in Enclosure (1). However, because of the delay in issuance of the above-mentioned SSER, BO&E is not able to submit a firm schedule to comp:ete the seismic portion of the IPEEE until after receipt and review of the SSER and in no case later than 120 days following receipt of the SSER. _ Following this re' 3.w, BG&E may modify its program for conducting the seismic IPEEE, depending on the content of the SSER end resolution of open issues.

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. ENCLOSURE (1)

. Response tu Generic letter 88 20 IPEEE Project Plan The IPEEE is scheduled to begin in the fourth quarter of 1992, after the submittal of the IPE final report. The full scope fire nacssment walkdowns and seismic capability walkdown, which will-follow the initial analytical evaluations, will be performed during the Unit 1 cleventh refueling outage and Unit 2 tcath refueling outage, currently scheduled for the first quarter of 1994 atid the fourth quarter of 1995, respectively. Based on the factors det .. ibed

, abcree, the evaluation is scheduled to be completed in early 1996. We plan to submit a summary report for both Units 1 and 2,in accordance with NUREG-1407, in June 1996.

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