ML18036B232

Responds to NRC Request for Info/Clarification of Functional Testing Frequency Changes to Support 920723 TS 316 to Licenses DPR-33,DPR-52 & DPR-68,upgrading Reactor Bldg Radiation Monitoring Sys.Applicable TS Encl

ML18036B232
Person / Time
Site:	Browns Ferry
Issue date:	04/06/1993
From:	Zeringue O TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML18036B233	List: ML18036B232 ML18036B234
References
NUDOCS 9304150062
Download: ML18036B232 (4)

Text

acczx,mm REGULA D DOCuvrzm DrSr RY INFORMATION DISTRIBUTI mrs svsxzM SYSTEM (RIDS)

C DEACCESSION.

NBR:9304150062 DOC.DATE: 93/04/06 NOTARIZED: NO DOCKET g 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 AFFILIATION ZERINGUE,O.J. Tennessee Valley Authority RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)

SUBJECT:

Responds to NRC request for info/clarification of functional testing frequency changes to support 920723 TS 316 to Licenses DPR-33,DPR-52 & DPR-68,upgrading reactor bldg radiation monitoring sys.Applicable TS encl.

DISTRIBUTION CODE: AOOID COPIES RECEIVED:LTR / ENCL ( SIZE:

TITLE: OR Submittal: General Distribution NOTES:

RECIPI'ENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD2-4 1 1 HEBDON,F 1 1 ROSS,T. 2 2 WILLIAMS,J. 2 2 INTERNAL: ACRS 6 6 NRR/DE/EELB 1 1 NRR/DORS/OTSB 1 1 NRR/DRCH/HICB 1 1 NRR/DSSA/SCSB 1 0 NRR/DSSA/SPLB 1 1 NRR/DSSA/SRXB 1 1 NUDOCS-ABSTRACT 1 1 QC/~Zm. 1 0 OGC/HDS3 1 0 REG FILE 01 1 1 EXTERNAL: NRC PDR NSIC 1 1 NOTE TO ALL"RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTEI CONTACT THE DOCUMENT CONTROL DESK, ROOM Pl-37 (EXT. 504-2065) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'7 NEED!

~R TOTAL NUMBER OF COPIES REQUIRED: LTTR ~ ENCL

0

~ ~. 1 1

4 1"

T 1

Tennessee Valtey Auttxxity, Post Oifice Box 2000, Decatur, Alabama 35609-2000 APR 06 1993 O. J. "Ike Zeringue Vice President. Browns Ferry Nuclear Plant 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) RESPONSE TO THE NRC REQUEST FOR INFORMATION-CLARIFICATIONOF THE FUNCTIONAL TESTING FREQUENCY CHANGES FOR TECHNICAL SPECIFICATION (TS) NO. 316 TVA'S PROPOSED UPGRADE OF THE REACTOR BUILDING RADIATION MONITORING SYSTEM (RBVRM) FOR BROWNS FERRY UNITS 1, 2, AND 3

Reference:

1. Telephone conversation between NRC and TVA/BFN on April 5, 1993.

2. Letter from TVA to NRC dated July 23, 1992, TVA BFN Technical Specification No. 316

3. TVA Calculation XD-Q0090-920001

4. TVA Calculation ED-Q0090-920073 TS-316 was submitted (Reference 2) in support of BFN's plans to upgrade the Browns Ferry reactor building and refuel floor radiation monitoring system from analog to digital for Units 1, 2, and 3. As part of the NRC staff's review of proposed amendment request TS-316, additional clarification (Reference 1) was requested concerning the functional testing frequency changes for the RBVRM subsystem.

As discussed with the NRC, the purpose of this submittal is to provide clarification of the functional testing frequency changes for the RBVRM subsystem. The bases change for paragraph 2, page 3.2/4.2-73 for Unit 1; paragraph 3, page 3.2/4.2-73a for Unit 2; and, paragraph 2, page 3.2/4.2-72 for Unit 3 are the only changes being proposed and are contained in the enclosure. These pages supersede those submitted by the Reference 2 letter.

U.S. Nuclear Regulatory Commission APR 06 553 The channel functional testing frequency is based upon a Probabilistic Risk Assessment (PRA) (Reference 3) that considered the probabilistic frequency of an accident with radioactive release into secondary containment concurrent with a failure of the RBVRM subsystem while one division of the RBVRM subsystem is out of service for power supply functional testing, calibration, or, maintenance. The calculated frequency for the above scenario is 9.7E-S/year. This is less than the NRC established acceptability threshold of 1E-7/year for design basis events with the potential to result in radiation exposures to the public in excess of 10 CFR 100 guidelines.

I The chassis high voltage power supply functional test frequency is based upon the system drift characteristics (Reference 4). The potential out-of-service time for an RBVRM chassis due to this monthly power supply check was considered in the previously discussed PRA.

TVA Calculations XD-Q0090-920001 and ED-Q0090-920073 are available for NRC inspection at TVA's Rockville office.

If you have any questions, contact G. D. Pierce, Interim Manager of Site Licensing, at (205) 729-7566.

Sincerely, Zeringue Enclosure cc (Enclosure):

NRC Resident Inspector Browns Ferry Nuclear Plant Route 12, Box 637 Athens, Alabama 35611 Mr. Thierry M. Ross, Pro)ect Manager U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852 U.S. Nuclear Regulatory Commission Region II 101 Marietta Streets NWg Suite 2900 Atlanta, Georgia 30323