ML20086S671

Responds to Suppl 4 to Generic Ltr 88-20, Individual Plant Exam of External Events for Severe Accident Vulnerabilities. Evaluation of High Winds,Floods & Transportation Expected to Be Completed by Oct 1993

ML20086S671
Person / Time
Site:	Summer
Issue date:	12/20/1991
From:	Skolds J SOUTH CAROLINA ELECTRIC & GAS CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GL-88-20, NUDOCS 9201030274
Download: ML20086S671 (4)

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Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20535 Gentlemen:-

Subject:

VIRGIL C. SUMMER NUCLEAR STATION DOCKET NO. 50/395 OPERATING LICENSE NO. NPF RESPONSE TO GENERIC LETTER 88-20, SUPPLEMENT 4 INTRODUCTION This letter provides a summary of the proposed Individual Plant-Examination of External Events (IPEEE) for the Virgil C. Summer Nuclear Station-(VCSNS),

as requested by NRC Generic Letter 88-20, Supplement 4, dated June 28, 1991, i

It also acknowledges that South Carolina' Electric & Gas Company (SCELG)'has received a copy of NUREG-1407, " Procedural and Submittal Guidance for the Individual Plant Examination of External Events (IPEEE) for Severe A wic3nt Vulnerabilities," Final Report (June 1991). The results of the proposed IPEEE program will be documented to meet the NRC_ submittal; guidance cutlined in NUREG-1407 The program description as summarized in this document _ includes the!'tems specified by Supplement 4 to meet-the generic letter, namely:

.1.

It identifies the methods and approaches selected for performing the IPEEE, ano 2.

-It identifies the milestones and schedule for performing-the IPEEE

-and submitting'the r_esults to the NRC.

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1 (4ETH005 AND APPROACHES TO PERFORMING THE IPEEE This section identifies the_ methods 11nitially-selected for performing the IPEEE. The method selected for! performing the. seismic evaluation portion of' theIPEEEistheEPRISeismicMarginsAssessment(SMA).-Theenhancements, identified in' Appendix 1.of Supplement 4 will=be-incorporated into the seismic evaluation. Also, a containment performance analysis will be.

performed by conducting an evaluation of a seismic event to identify any vulnerabilities that involve early; failure of containment functions. The method selected for conducting the internal fire' evaluation is the EPRI Fire-Induced Vulnerability _ Evaluation-

-and approved by HRC on August 21,(FIVE)' approach. _.This' approach was reviewed-1991. A containment-performance assessment 9201030274 911220 T

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y, Document Control Desk LTR 880020 Page 2 of 3 will be performed to determine if containment failure modes differ significantly from those found in the IPE internal events evaluation. -An examination for other significant external events will also be performed to determine if the plant design meets the 1975 Standard Review Plan ($RP) criteria.

The screening approach identified in Figure 1 of Supplement 4 will be used. The methods chosen by SCELG for the IPEEE are described in Supplement 4 to the Generic Letter and details'are provided in NUREG-1407 SCELG has assigned engineers and operations personnel to provide support for the IPEEE project.

IPEEE SCHEDULE A @ MAJOR MILESTONES SCE&G cannot p sform the total IPEEE effort and submit the results to NRC by June 1994 as requested in Supplement 4 to the Generic Letter. There are 's nutter of reasons why the June 1994 request date cannot be met by SCE&G.

The primary reason is that the request date would not allow significant utility involvement in the IPEEE examination process. Also SCE&G will not complete the IPE submittal until June 30, 1993. The IPEEE will require some of the same resources required to complete the IPE and the IPEEE will benefit

directly from'the experience / insights gained from the'IPE.

It is anticipated that the IPEEE project will also compete for resources with other necessary SCELG projects. For instance. SCE&G will implement a steam generator replacement and possible plant power uprate by 1996.

In addition to competing for resources with this project, the plant equipment changes may impact the seismic evaluation. Since the IPEEE is expected to be a one-time evaluation, and the most heneficial portion of the seismic evaluation is the plant walkdown the maximum benefit will be achieved by performin9 the seismic evaluation after the steam generator replacement and associated modifications are completed.

Proposals for support of IPEEE activities have been requested from various vendors and the proposal evaluation process will begin by mid-January 1992.

The schedule duration for completion of the study is 64 months.

The targeted completion date for this effort is October 1997. The major milestones for the IPEEE are.

Bid Evaluation Completion end Contract Award June 1992 IPEEE Project Plan Completed January 1993 Completion of High Winds. Floods, and Transportation and Nearby Facilities Accidents Evaluation October 1993

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l Document Control Desk LTR 880020 Page 3 of 3 l

Submittal Report for Other External Events to NRC J&nuary 1994 f

Completion of Fire Evaluation October 1995 Submittal Report for ftre to NRC March 1996 i

Completion of Seismic Evaluation April 1997 Submittal Report for Seismic to NRC October 1997 Since the IPEEE project will extend over a six year period, it is proposed that a separate report for each of the three IPEEE phases be submitted to the NRC upon completion of each phase.

Figure 1 provides the overall schedule for the severc accident projects covered under Generic Letter 88-20, including accident management (AM).

Scheduled plant outages are also shown in this figure.

In summary. SCEtG considers the propo'ed schedule to be realistic and achievanie. A shorter time frame wouid limit the amount of.SCE&G involvement in ti.e evaluation and could adversely affect the quality and usefulness of the IPEEE.

I declare that the statements and matters set forth herein are true and correct to the best of my knowledge.

If you have any questions, please call.

Very truly ours.

John L. Skolds ARR:JLS:sd c:

0. W. Dixon Jr.

J. B. Knotts, Jr.

R. R. Mahan D. Modeen (NUMARC)-

R. J. White B. S. Mullinax S. D. Ebneter NSRC G. F. Wunder RTS (LTR 880020)

General Managers file (815.141 NRC Resident inspector NUCLEAR EXCELLENCE - A SUMMER TRADITION!.

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