ML20085G116

AO BFAO-7329W:on 731018 & 19,HPCI Inverter Power Supply Fuse Failed.Caused by Wiring Error Resulting from Design Change. Wiring Corrected & Tested

ML20085G116
Person / Time
Site:	Browns Ferry
Issue date:	10/26/1973
From:	Eric Thomas TENNESSEE VALLEY AUTHORITY
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20085G119	List: ML20085G116 ML20085G122
References
AO-BFAO-7329W, NUDOCS 8308240293
Download: ML20085G116 (2)

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,,,, d. i TENNESSEE VALLEY CHATTANOOGA, AUTHOFitTY TENNESSEE  : t~~":igs.i

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!ct k2 October 26, 1973 ANN VEA5IAY 9 D a 05ETNSYs"H 00 ,[ fo :' '& h e

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Mr. John F. O'Ieary, Director , kv.g,, 28/g h ^Y g

j Directorate of Licensing ' a ,- p Office of Regulation Af,. , ,v,pgf 3

U.S. Atomic Energy Commission ~ %,.

Washin6 ton, DC 20545 N

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Dear Mr. O'Ieary:

TENITSSSEE VALIEY AUTHORITY - BROWNS FER'iY h"JCLEAR PIET UNIT 1 -

DOCKET no. 50-259 - FACILITY OPERATING LICENSE DPR ASNO W.AL OCCURREHCZ REPORT EFAC-7329W The purpose of this report is to provide details of the HPCI inverter power supply fuse failure which occurred on October 18 and 19,1973, at Browns Ferry Huclear Plant unit 1. The occurrence was reported by telegram on October 19 to the Region II Directorate of Regulatory Operations, Atlanta, Georgia.

Description of the Incident At 12:15 p.m. on October 18, the HFCI system was declared inoperable because of a bloda fuse in the EPCI inverter power supply. The reactor -

was in the process of a nomal shutdown when the failure occurred. The fuse was replaced 1- ediately and the EPCI declared operable. The fuse

! failed again during reactor.startup at 10:30 a.m. on October 19 The

! fuse was replaced i m ediately and HPCI declared operable. A functional test at rated te=perature and pressure demonstrated satisfactory operation.

4 Investigation and Corrective Action This occurrence is similar to previous failures reported on September 18 2

as BFAO-739W and Septenber 29'as EFAO-7318W. As stated in EFAO-731SW, a modified inverter was installed on September 18. A filter was added to the 2507 de input on October 9 as additional protection against voltage spikes. Additional caps itance was added to this filter en October 18 after the fuse failure. It was observed during the failure on October 19 that the reactor vessel low-water level alem ca=c in

,just before the fuse blowing. On investigation, a viring error resulting from a design change was discovered. When the reactor vessel low-water 8308240293 731026 PDR ADOCK 05000259 S PDR

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Mr. John F. O' Leary October 26, 1973 TEli!IESSEE VALLIZ NJTECRITY - ERCU !S FERRY NUCISAR PLtdiT UIIIT 1 -

DOCKET : 0 50-259 - F.iCILITY OPERATIIIG LICE:ISE DPR /G:iOFMAL ,

OCCURPS:CE FSPORT EFAO-7329J level alarm was actuated, the viring error was superimposing a negative ll0V 4 de voltage on the HPCI auto icolation logic circuit which sharec a coc: mon power supply feeder with the HPCI inverter. The viring was corrected to agree with cpproved drawings. Functional tests were conducted to check out the corrected viring. All tests were completed successfully.

Very truly yours, TEN::ESSEE VAIlEY AUTEORITY (sf f0 AYff E. F. Thomas Director of Power Production a

CC: l'r. :!cnnan C. I.'oseley, Director Region II Regulatory Operations Office, USAEC .

230 Peac'.1 tree Street, Ii'J.

Atlanta, Georgia 30303 O' 6

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