ML20085G430

AO BFAO-50-260/7434W:on 741208,leak Indications Found on Main Steam Relief Valve Bellows 2-PCV-1-41 & 2-PCV-1-5. Caused by Shorted Cable Due to Melted Cable Insulation. Caused Repaired

ML20085G430
Person / Time
Site:	Browns Ferry
Issue date:	12/18/1974
From:	Eric Thomas TENNESSEE VALLEY AUTHORITY
To:	Case E US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20085G434	List: ML20085G430 ML20085G444 ML20085G454
References
NUDOCS 8308290086
Download: ML20085G430 (2)

Text

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ABNORMAL OCCURRE!CE RF. FORT O

Report Ho'.: BFAO-50-260/7h3411 O -

. Report Date: December 18, 1974 Occurrence Date: Dece=ber 8, 1974 l Facility: Browns Feny Nuclear Plant unit 2 Identification of Occurrence Main steam relief valve bellows leak indication on 2-PCV-1-41 following simil e leak indication on 2-PCV-1-5 Conditions Prior to Occurrence The unit was operating at approximately 594 I.Jc. Safety relief valve 2-PCV-1-5 had already been declared inoperable for pressure actuation due to an indication of bellows leakage as noted in BFAO-50-260/7433T. This written report covers BFAO-50-260/7433I and BFAo-5C-260/7434T.

Descrip'tion of Occu-rence At 2240 the control room received annunciation " Auto Blowdown Relief Valves Bellows Leck" on valve 2-PCV-1-41. 111th 2-PCV-1-5 already inoperable, an orderly

. shutdown was initiated.

Desirmatien of 1.rearent Cause of Occurrence Upon inspection of valve 2-PCV-1 kl, it was found that the indication of bellows leakage was caused by a shorted cable going to the bellows leakage pressure switch.

Slack in the cable during installation of pipe insulation had become pinched 'cetween the Mirrer inculatica and the steert pipe. The heat from the pipe was trcnsnitted to the cable causing the cable insulation to telt. Tnis cllowed the two conductors of the cabic to short together, bringing in the alarm. A similar condition was found on valve 2-?CV-1-5, Analysis of Occurrence I '

Both valves were still capable of performing their ADS functions. Indicationc vere that neither would recpond to pressure actuation. This occurrence cauced -

i no damage to any other systers, structures, or components. There were no adverse '

effects to the health and safetf of the public, and there were no personnel injuries or exposures due to this occurrence. I i

Corrective Action ..-

i 1

i The faulty cables were repaired for both valves. Care was taken to keep the cable from coming in centact with the steam pipes. Tce other nine valves were inspected to make cure that this condition did not exist. Furthermore, a discussion van  !

' held with personnel involved in the insulation of steamlines to relate to then the i=portance of not allowing electrical cables to come into contact with the stee= lines, i

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TENNESSEE VALLEY AUTHORITY CHATTANOOG A. TENNESSEE 374ot

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Mr. Edson G. Case , q Acting Director of Licensing y

1. U p Office of Regulation U.S. Atomic Energy Connission I. ', M h

liashington, DC 20545  !

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Dear Mr. Case:

.9 T.:2i1TESSEE VALLEY AUTHORITY - 3ROICS FERRY ITUCLFAR PLAIIT UITIT 2 -

j hi DOCET liO. 50-260 - FACILITY OPERATIl!G LICE'ISE DPR ABITORMAL 'l OCCURRIICE REPORT BFAO-50-260/7434W .i 7

The enclosed report is to provide details concerning r.ain steem relief If l

valve bellows leak indication on 2-PCV-1-41 following similar leak '1 indication on 2-PCV-1-5 and is submitted in accordance with Appendix A '

s j to Regulator / Guide 1.16, Revision 1, October 1973. This event i occurred o1 Browns Ferr/ Ituelear Plent unit 2 on Decccber 8,1974 1

Very truly yours, I

TEIEIESSEE VALLEY AUTHORITY @,

Udm l E. F.' Thomas ei Director of Power Prodaction ]

)2 Enclosure.

CC (Enclosure): }

} Mr. I!or en C. Ibseley, Director ;j j Region II Regulator / Operations _ Office, USAEC  ;(

i 230 Peachtree Street,IiW., Suite 813 i Atlanta, Georgia 30303 p 9

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