ML20012F261

Provides Supplemental Response to Station Blackout Rule. Target Reliability of 0.975 Chosen for Emergency Diesel Generators.Diesel Generator Reliability Program May Change Based on Final Resolution of Generic Issue B-56

ML20012F261
Person / Time
Site:	Crane
Issue date:	04/02/1990
From:	Hukill H GENERAL PUBLIC UTILITIES CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
REF-GTECI-B-56, REF-GTECI-EL, TASK-B-56, TASK-OR C311-90-2029, NUDOCS 9004110034
Download: ML20012F261 (2)

Text

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OPU Nuclear Corporation N

gf Post Office Box 400 l

Route 441 South t

3 Middletown, Pennsylvania 17057 0191 i

i 717 944 7621 i

TELEX 64 2366 Writer's Di *ct Dial Number:

i April 2, 1990 f

C311-90-2029 i

U.S. Nuclear Regulatory Commission i

Attn: Document Control Desk Washington, D.C.

20555 t

i

Dear Sir:

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i Three Mile Island Nuclear Generating Station, Unit 1 (TMI-1)

Operating License No. DPR 50 Docket No. 50 289 Station Blackout: NUMARC Request for Supplemental l

SB0 Submittal to NRC i

l On July 21, 1988, the Nuclear Regulatory Commission amended its regulations in l

10CFR50, adding a new section,10CFR50.63, " Loss of all alternating current power." This section requires each light-water cooled nuclear power plant be able to withstand and recover from a station blackout (SBO) of a specified duration.

Regulatory Guide (RG) 1.155, dated August, 1988, describes a means acceptable to the NRC staff for meeting the requirements of 10CFR50.63 and concludes that NUMARC 87-00 provides guidance for conformance to 10CFR50.63 that is in large i

part identical to the guidance provided in the Regulatory Guide. Table 1 of the RG provides a cross-reference to NUMARC 87-00 and notes when the RG takes l

precedence.

i I

On April 17, 1989, GPUN submitted its response to the SB0 rule.

By letter dated December 18, 1989, the NRC forwarded its safety evaluation report (SER) i for the above submittal.

The SER concludes that the TMI-1 SB0 response meets l

the requirements of 10CFR50.63, the criteria of NUMARC 87 00 and RG 1.155.

Subsequent to the above, NUMARC requested, via their January 4, 1990 letter, that licensees re-evaluate their SB0 responses in accordance with the guidelines set forth therein and submit a supplemental $80 submittal to the NRC l

by March 30, 1990. The purpose of this re-evaluation is to assure the availability of proper suoporting documentation and consistent implementation of NUMARC 87-00 guidance.

GPUN has reviewed its TM1-1 SB0 submittal pursuant i

to the criteria delineated in the NUMARC letter and reaffirms the following:

l 9004110034 900402 PDP ADOCK 05000289

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PDC lk f

GPU Nuclear Corporation is a subsidiary of General Pubhc Utihties Corporation

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C311-90 2029 April 2, 1990 i

l 1.

GPUN has evaluated TMI-1 against the requirements of the SB0 rule using guidar 9 from NUMARC 87-00 except where RG 1.155 takes precedence.

RG 1.155 Sections 3.3.6, 3.5, Appendices A and B taks precedence over NUMARC 87 00.

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2.

Implementation of the NUMARC 87-00 guidance is consistent with the j

supp1 mental guidance provided in the enclosures to the NUMARC letter, j

i 3.

Applicability of NUMARC B7 00 assumptions, which are applicable to f

l TM1-1, are appropriately documented.

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l 4.

In developing the SB0 submittal GPUN did not depart from the accepted and applicable NUMARC 87 00 methodology.

[

i TM1-1 has chosen a target reliability of 0.975 for the Emergency Diesel i

i Generators (EDGs),

it is important to point out that the 0.975 value is a target reliability value for the EDGs chosen by considering various factors such as off site power design characteristics and the EDG configuration.

It is i

not the reliability value derived from test data considering only the number of actual and attempted starts. While GPUN does have an emergency diesel generator reliability program in place, it recognizes that such a program may change when there is a final resolution to Generic Issue B-56, " Diesel i

Generator Reliability.

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Sincerely.

l l

h/'

M [n.-

H. D. Hu ill Vice President & Director, TM1-1 HDH/EP/cjg I

References:

1. TMI-1 SB0 Ri e Response, letter C311-89-2018, dated April 17, 1989.

2. SER of the TMI-1 Response to the SB0 Rule, dated December 18, 1989.

3. Response to SB0 Rule SER, letter C311-90-2006, dated January 25, 1990.

4. NUMARC letter dated January 4,1990, SB0 Implementation:

Request for supplemental SB0 submittal to NRC.

t cc: NUMARC i

R. Hernan F. Young J. Stolz T. Martin l

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