ML20042F770

Provides Results of Review of Util 890418 Submittal Re Supplemental Implementation of NUMARC 87-00 on Station Blackout.Implementation of 10CFR50.63 Consistent W/Guidance Provided by NUMARC 87-00

ML20042F770
Person / Time
Site:	Browns Ferry
Issue date:	05/04/1990
From:	Wallace E TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9005090371
Download: ML20042F770 (5)

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• TENNESSEE VALLEY AUTHORITY

- CH ATTANOOGA, TENNESSEE 37401 h'

SN 157B' Lookout: Place MAY 041990 i r

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.U.S.-Nuclear Regulatory Commisslon

-ATIN: Document Control Desk '

Washington, D.C; 20555 Gentlemen: 'i

' the Matter of ) Docket Nos. 50-259

- Tennessee Valley Authority _ ) 50-260 50-296 BROWNS

. FERRY NUCLEAR PLANT (BFN) - SUPPLEMENTAL OF STATION BLACXOUT (SILO)

IMPLEMENTATION OF NUMARC 87-00 GUIDANCE This letter provides the results of the review of BFN's' previous submittal

'made on' April- 18,-1989, NUMARC 87-00 supplemental questions and answers,-and specific NUMARC 87-00 major assumptions as requested in the NUMARC letter of January:4, 1990.

Details of the.BFN review are provided in Enclosure 1. Enclosure 2 contains a summary list of BFN commitments.  ;

=If_you have any questions, please telephone Patrick P. Carter at

-(205)-729-3566.

Very truly.yours,  ;

' TENNESSEE VALLEY AUTil0RITY E. G. lallace, landger Nuclear Licensing and Regulatocy Affairs Enclosures s- cc: See page 2

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9005090371 900504 "

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PDR. ADOCK 05000259 i P' PDC An Equal Opportunity Employer

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U.S. Nuclear ~ Regulatory Commission .MAY 041990 l

cc (Enclosures):

Ms. S. C. Black, Assistant Director for Projects TVA Projects Division U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852 NRC Resident Inspector Browns Ferry Nuclear Plant Route 12, Box 637 Athens, Alabama 35609-2000 Mr. B. A. Wilson, Assistant Director for Inspection Programs TVA Projects Division U.S. Nuclear Regulatory Commission ,

Region II j 101 Marietta Street, NW, Suite 2900 1 Atlanta, Georgia 30323 i i

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. BROWNS FERRYLIMPLEMENTATION OF:NUMARC 87-00 i -' GUIDANCE ONcSTATION. BLACKOUT-($80)-

yw NUMARC-'has. requested that utilities supplement.their previous.SB0 submittals L' _

Lto-NRC with~a letter verifying that:

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$ II.--iPrevio'ussubmittalLwasbasedonuseoftheNUMARC87-00guidanceincluding L * .the clarifications identified during meetings with.NRC, and/or:

'2. 'Any deviations from thel accepted NUMARC 87-00 guidance have been or will be' clearly- indicated. '

%, A R ' ' In addition =, affirmation should be made that the diesel generator target g, ' reliability: chosen for each plant-(0.95 or 0.975) is to be maintained.

'I W Verification should:also be made that applicability of NUMARC 87-00--

assumptions is' documented inLutility files.

e' BFN has reviewed TVA's previous submittal utilizing the clarifications received from NUMARC'and' determined that implementation of.10LCFR 50 f>3 is-

' consistent with the guidance provided by NUMARC 87-00 and the supplemantal guidance provided in NUMARC's letter dated January 4, 1990. BFN's program for

. compliance has been reviewed by Bishop, Cook, Purcell, and Reynolds in-

1. conjunction with NUMARC, and.their recommendations were incorporatedLinto the previour. SB0 subilttal.

. Diesel generator.(DG) target reliability of 0.975 was chosen.for.BFN and is-being maintained. l The:. actual BFN diesel generator. reliability. since.0ctober a

1988 untti.present is 0.995- .

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, :BFN has also. reviewed the list of major NUMARC assumptions provided in their letter dated January 4,'1990, .The evaluation of each assumptionJandithe BFN implications are discussed below as identified by~the applicable NUMARC 87-00 section number:

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. Section.No. 2.4.1(1)

The' loads. associated with breaker operations necessary for offsite AC power m utestoration are quantified and~ included in the battery calculation. The? ,q r'

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emergency diesel generators are not used to mitigate the SB0 event, and' therefore the diesel batteries are not included in BFN's battery calculation.

j Section No. 2.5.2

'The recirculation pump seal leakage rate of-15 gpm (12.5 gpm per pump) was 1

'4 rused'in BFN's SB0 analysis. In reviewing the analysis, it was concluded that 1

-a -minimam leakage rate of 18 gpm (consistent with NUMARC) per pump, or a total-

• oft 36 gpm for both pumps should have been used. Further review of the ,

. analysis shows-that sufficient margin exists to support the 36 gpm for both pumps. TVA wlil revise the affected documents to correct this discrepancy. j]

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_. Enclosure 1 Page 2 Section No. 2.7.1

The assumption that loss of Coolant Accident /High Energy Line Break ~

(LOCA/HELB) temperature profiles enveloped the SB0 temperatures was not used in the BFN SB0 analysis. Temperatures applied in the analysis were calculated n for the SB0 event.

Section No.- 2.7.l(2)(a)

The control room temperatures for the SB0 event are verified in the BFN SB0 analysis not to exceed 120 degrees F and all major assumptions were applied correctly, Section No. 2.7.l(2)b)

=The battery capacities _were evaluated using the minimum normal temperature of

-76 degrees F. This is within the requirements stated in the NUMARC assumption.

CONCLUSIONS The BFN.SB0 evaluations are based on the prescribed NUMARC methodology and on the information contained in NUMARC reference NUREG/CR-2182, Oak Ridge National-Laboratory, November 1981, " Station Blackout at Browns Ferry Unit 1." The NUREG was independently verified by TVA calculation and this enclosure documents the applicability of the NUMARC 87-00 assumptions. BFN concludes that the original submittal to NRC meets the requirement of 10 CFR 50.63.

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