ML18033B670

Advises That Util Reevaluated Effects of LOCA Occurring While Containment Purged Through Standby Gas Treatment Sys Using 18-inch Drywell Exhaust Valves,Per 900604 Application for Amend to TS to Clarify Use of Containment Purge Sys

ML18033B670
Person / Time
Site:	Browns Ferry
Issue date:	04/16/1991
From:	Zeringue O TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9104230091
Download: ML18033B670 (7)

Text

ACCELERATED DISTRIBUTION DEMONSTPA.TION SYSTEM i

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REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9104230091 DOC.DATE: 91/04/16 NOTARIZED: NO DOCKET FACIL:50-259 Browns Ferry Nuclear Power Station, Unit 1, Tennessee 05000259 50-260 Browns Ferry Nuclear Power Station, Unit 2, Tennessee 05000260 50-296 Browns Ferry Nuclear Power Station, Unit 3, Tennessee 05000296 AUTH. NAME AUTHOR AFFILIATXON ZERINGUE,O.J. Tennessee Valley Authority RECIP.NAME RECIPIENT AFFXLIATION Document Control Branch (Document Control Desk)

SUBJECT:

Advises that util reevaluated effects of LOCA occurring D wh'ile containment purged through standby gas treatment sys using 18-inch drywell exhaust valves,per 900604 application for amend to TS to clarify use of containment purge sys.

DISTRIBUTION CODE: AOOID TITLE: OR COPIES RECEIVED:LTR Submittal: General Distribution g ENCL Q SIZE:

A NOTES:1 Copy each to: B.Wilson,S. BLACK 05000259 1 Copy each to: S.Black,B.WXLSON 05000260 D 1 Copy each to: S. Black,B.WXLSON 05000296 D

RECXPIENT COPIES RECIPIENT COPIES XD CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL KREBS,M. HEBDON,F ROSS,T.

INTERNAL: ACRS NRR/DET/ECMB 9H NRR/DET/ESGB NRR/DOEA/OTSB11 NRR/DST 8E2 NRR/DST/SELB 8D NRR/DST/SICB 7E NRR/DST/SRXB 8E NUDOCS-ABSTRACT OC FMB OGC/HDS3 REG L 01 RES/DSXR/EIB EXTERNAL: NRC PDR NSIC NOTES D

D NOTE TO ALL "RIDS" RECIPIENTS' PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOM Pl-37 (EXT. 20079) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!

TOTAL NUMBER OF COPIES REQUIRED: LTTR 29 ENCL

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Tenrtessee Valley Authority, Post Otfice Box 2000. Decatur. Alabama 35609 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 Gentlemen:

In the Matter of Docket Nos. 50-259 Tennessee Valley Authority 50-260 50-296 BROWNS FERRY NUCLEAR PLANT (BFN) PRIMARY CONTAINMENT PURGE SYSTEM

Reference:

TVA letter, dated June 4, 1990, BFN Technical Specification No. 273-Primary Containment Purge System The referenced letter submitted a request for an amendment to the BFN Technical specifications to clarify the use of the Containment Purge System. This submittal included proposed revisions to Specification 3.7.F, "Primary Containment Purge System". TVA and NRC met on February 6, 1991 and February 25, 1991, to discuss this proposed amendment. NRC expressed a concern regarding the purging of the containment atmosphere through the Standby Gas Treatment System (SGTS). This purging could reduce the reliability of the SGTS. If a Loss of Coolant Accident (LOCA) occurred during this purging, the SGTS could be over-pressured and become inoperable.

The issue regarding the adequacy of the BFN containment purge isolation valves was previously raised by NRC in a November 1978 Generic Letter. TVA performed an analysis which showed the containment purge valves will close under the loading imposed by a design basis LOCA. TVA reduced the valve closure time for the large purge valves to less than 2.5 seconds to reduce the analytical doses and to protect against pressurization of appurtenant duct work and secondary containment. The analysis of the purge valves was reviewed and found acceptable in the NRC's December 17, 1981, Safety Evaluation.

9104230 09i 910416 PDR, ADOC 0+000259

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U.S. Nuclear Regulatory Commission 4pR f6 lN Since the wording of TVA's previous submittals and the NRC's Safety Evaluation may be subject to interpretation, NRC requested TVA docket a clarification to resolve the NRC concern. TVA has re-evaluated the effects of a LOCA occurring while the containment is purged through the SGTS using the 18 inch drywell exhaust valves. TVA has concluded that a LOCA will not jeopardize any SGTS components or piping such that the safety function of the system is inhibited.

There are no commitments contained in this letter. If you have any questions please get in touch with Patrick P. Carier, Manager of Site Licensing, at (205) 729-3570.

Very truly yours, TENNESSEE VALLEY'UTHORITY V e President Browns Ferry Operations Enclosures cc: See page 2

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. U.S. Nuclear Regulatory Commission cc: Ms. S. C. Black, Deputy Director Project Directorate II-4 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. Thierry M. Ross, Project Manager U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852 Mr. B. A. Wilson, Project Chief U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323

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