ML18038B735

Forwards LER 50-296/96-004 Which Provides Details Re Loss of Instrumentation Input Logic for Plants Division I Eccs. Broader Evaluation of Inverter Problems Being Conducted Due to Aggregate of Events

ML18038B735
Person / Time
Site:	Browns Ferry
Issue date:	08/16/1996
From:	Machon R TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML18038B736	List: ML18038B735 ML18038B737
References
NUDOCS 9608220101
Download: ML18038B735 (6)

Text

REGULATORY INFORMATION DISTRIBUTION SYSTEM,(RIDS)

ACCESSION NBR:9608220101

~ DOC.DATE: 96/08/16 NOTARIZED: NO ACIL:50-296 Browns Ferry Nuclear Power Station, Unit 3, Tennessee DOCKET t 05000296 AUTH. NAME AUTHOR AFFILIATION CHON,R.D. ~ Tennessee Valley Authority RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)

SUBJECT:

Forwards LER 50-296/96-004 which provides details re loss of instrumentation input logic for plants Division I ECCS.

Broader evaluation of inverter problems being conducted due to aggregate of events. A DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR TITLE: 50.73/50.9 Licensee Event Report (LER), Incident,Rpt, etc.

ENCL SIZE: +4 NOTES:

RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL 0 PD2-3-PD 1 1 WILLIAMSgJ. 1 1 INTERNAL: ACRS 1 1 AEOD SPD RAB 2. 2 AEOD/SPD/RRAB 1 1 E CEN E 1 1 NRR/DE/ECGB 1 1 NRR/DE EE 1 1 NRR/DE/EMEB 1 1 NRR/DRCH/HHFB 1 1 NRR/DRCH/HICB 1 1 NRR/DRCH/HOLB 1 1 NRR/DRCH/HQMB 1 1 NRR/DRPM/PECB 1 1 NRR/DSSA/SPLB 1 1 NRR/DSSA/SRXB 1 1 RES/DSIR/EIB 1 1 RGN2 FILE 01 1 1 D

EXTERNAL: L ST LOBBY WARD 1 1 LITCO BRYCEgJ H 2 2 NOAC MURPHY,G.A 1 1 NOAC POORE,W. 1 1 0 NRC PDR 1 1 NUDOCS FULL TXT 1 1 E

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t NOTE TO ALL "RIDS"'ECIPIENTS:

PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOM OWFN 5D-5(EXT. 415-2083)

DISTRIBUTION LISTS TO ELIMINATE YOUR NAME FROM FOR DOCUMENTS YOU FULL TEXT CONVERSION REQUIRED TO'ZAL NUMBER OF COPIES REQUIRED: LTTR DON'T NEED!

26 ENCL 26

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Tennessee Yarey Aurtxn;y. pcsr 0".,ce Bex 2"cc. "~r~r, Aacar, a 3HC9 2~Ac R. D. (Rick) Machon Yce Presdenr, Browrs Ferry Nudear Pranl August 16, 1996 U.S. Nuclear Regulatory Commission 10 CFR 50.73 ATTN: Document Control Desk Washington, D.C. 20555

Dear Sir:

BROWNS FERRY NUCLEAR PLANT (BFN) - UNITS lg 2p AND 3 - DOCKET NOS~ '50-259~ 260~ AND 296 - FACILITY OPERATING LICENSE DPR-33'2'ND 68 - LICENSEE EVENT REPORT 50-296/96004 The enclosed report provides details concerning the loss of instrumentation input logic for the plant's Division I Emergency Core Cooling Systems (ECCS). The July 17, 1996, event was presumed to be caused by a failed control board in the ECCS Division I Analog Trip Unit Inverter. On August 6, 1996, a similar event occurred. When TVA has determined the root causes and has taken appropriate corrective actions for both events to preclude recurrence of this type of an event, TVA will submit a supplemental report.

TVA has had previous similar events. At this time, TVA believes that corrective actions taken to resolve those events would not have precluded this event. However, due to the aggregate of these events, TVA is conducting a broader evaluation of inverter problems. Consequently, TVA's current presumption that past inverter problems were separate and isolated may change. This evaluation result will be addressed in the supplemental report.

This report is submitted in accordance with 10 CFR 50.73 (a) (2) (vii) .

Sincerely, t

R. D. hon Enclosure cc: See page 2 9b08220101 9b08ib PDR ADQCK 0500029b 8 PDR

II U.S. Nuclear Regulatory Commission Page 2 August 16, 1996 Enclosure cc (Enclosure):

Mr. Mark S. Lesser, Branch Chief U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW,,Suite 2900 Atlanta, Georgia 30323 NRC Resident Inspector Browns Ferry Nuclear Plant 10833 Shaw Road Athens, Alabama 35611 Mr. J. F. Williams, Project Manager U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852

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