ML20085G281

AO BFAO-7324W:on 731015,stack Gas Sample Pump a Motor Failed.Caused by Overheating & Deterioration of Motor Insulation.Spare Motor Installed,Sample Sys Returned to Svc & Design Changes Re Motor Circuitry Proposed

ML20085G281
Person / Time
Site:	Browns Ferry
Issue date:	10/25/1973
From:	Eric Thomas TENNESSEE VALLEY AUTHORITY
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
References
BFAO-7324W, NUDOCS 8308240759
Download: ML20085G281 (2)

Text

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-~,. TENNESSEE VAL Y AUTHORITY E~~"a

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October 25, 1973 g4 h3-.7h% $E"Nhf0bd%

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\ s a l(%' gA :s Mr. John F. O' Leary, Director Directorate of Licensing p 8 -

1 i Office of Regulation

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U.S. Atomic Energy Co= mission .

Washington, DC 20545 O I

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Dear Mr. O'Icary:

TE UTESSEE VAllXl AUTHCRITY - BRCW::S FERRY HUCIIAR PLANT U:iIT 1 -

DOCKET !!O. 50-259 - FACILITY OPERATING LICEHSE DPR AB:lGFMAL CCCUR?Z:!CE REPCRT BFAO-7324W The purpose of this report ic to provide details concerning the failure of the stack gas monitoring system at Browns Ferry Huclear Plant. This occurrence was reported by telegram BFAO-7324T dated October 16, 1973, to the Directorate of Regulatory Operations, U.S. Atomic Energy Ccamission.

Description of the Incident e

f.t 11: 35 a.m. cn Ceteba 15, the :: tack gar staple pump "A" totor failei.

Attempts to place "B" pump in service failed. The reactor was operating at approximately 8-percent pover. The "A" pump motor was replaced and the stack gas confter system was returned to service at 12:50 p.m.

• Investigation and Corrective Action The A and B stack gas sample pump motors failed as a result of overheatin6 and deterioration of motor insulation. The overheating was caused by live

' , voltage. drop. inf th6 undergize'd .pover. supply] cable fFori'battetj. board 2 't:b - ~-

'p'anel 25-39 The motors were provided with low-te=perature insulation, and this contributed to a more rapid failure.

A spare motor was installed and the sample system returned to service.

The sample system was inoperable for an hour and 15 minutes.

':lere were no ricnificant cher.gcc to t::a relence rate from the stack ar.1 the power level during the period that the stack monitor was inoperable. I Tne releace rate during this period uas less than 1 percent of the most )

restrictive technical specifications release rate limit. l

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8308240759 731025 PDR ADOCK 05000259 -' T' 1 S 7 J PDR

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Mr. John F. 0' Leary .

October 25, 1973 TEN:ESSEE VALIEY AUTEORITY - BROWNS FERRY NUCLEAR PIRiT UNIT 1 -

DOCKET NO. 50-259 - FACILITY OPERATING LICENSE DPR ABNGRMAL OCCURRENCE REPORT hFAc '732W Subsequent corrective action has been the replacement of both semple Vork is pump motors with motors revound using class H insulation.

currently in progress to change the No. 8 size power supply cable to No.1/0 conductors. Proposed design changes to motor circuitry to improve relinbility have been cubmitted. Thece changes include dividing the pcuer and control circuits including the fuses down to the pump selector critch.

Very traly yours, TEIRESSEE VALLEY AUTHORITY G'

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, E.{F.~Thbcas J D ifector of Power Production L

4 CC: Mr. Norman C. Moseley, Director Region II Regulatcry Operations Office, USAEC

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230 Peacht' rec Street, L'.

Atlanta, Georgin 30303 9 W 9

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