ML20151U161

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PNO-77-080:on 770510,while Controlling Reactor Pressure Through Manual Relief Valve Operation,Following Reactor Trip as Result of Transmission Line Failure Due to Storm Condition,One Relief Valve Failed to Operate
ML20151U161
Person / Time
Site: Pilgrim
Issue date: 05/12/1977
From: Dreher F, Roy G, Thompson D
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
To:
References
PNO-77-080, PNO-77-80, NUDOCS 9809100309
Download: ML20151U161 (1)


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PRELIMINARY NOTIFICATION May 12, 1977  !

PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-77-80 This preliminary notification constitutes EARLY notice of an event of POSSIBLE safety or public interest significance. The information presented is as initially received without verification or evaluation and is basically all that is known by IE staff on this date.

Facility: Pilgrim Unit No. I '

Plymouth, Massachusetts  :

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Subject:

TARGET ROCK RELIEF VALVE DIAPHRAGM FAILURES I L

While controlling reactor pressure through manual relie' valve operation, following a reactor trip on May 10, 1977, as a result of a transmission -

line failure due to a storm condition, one relief valve failed to operate.

The nctor was placed in a cold shutdown condition and the relief valve and relief valve air operator diaphragms inspected. Two diaphragms were . Jentified as failed. Three of the four diaphragms installed f.ed been in service since 1972. One was renewed last year. All three 1972 diaphragms have been replaced.

t The plant is expected to return to power operation today.

' Media interest is not expected. The Commonwealth of Massachusetts has g;y

. m been informed. A press release is not planned. - ~

NRC, Region I, (Philadelphia) received notification of this occurrence by telephone from the Plant Superintendent at 11:30 a.m. , on May 12, 1977. '

Contact:

FADreher, IE x27261 GWRoy, IE x27261 DThompson, IE x27541 i Distribution: Transmitted H St /18~.?

Chairman Rowden C. C. Kammerer, CA G. F. Murphy, JCAE Commissioner Kennedy S. J. Chilk, SECY H. H."Whiteside, SCNR Commissioner Gilinsky H. R. Myers, HCEE .

' Transmitted: MNBB'.!O[ PBldg./!!N SS Bldg 2-L. V. Gossick, ED0 E. G. Case, NRR C. V. Smith, NMSS S. H. Hanauer, ED0 J. A. Harris, PA W. G. Mcdonald, MIPC Luge (MAIL) IE R. G. Ryan, OSP T. J. McTiernan, 0IA E. Volg,enau)!

Region ,- /3 H. K. Shapar ELD PRELIMINARY NOTIFICATION i '

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l 9809100309 770512 w PDR 18cE D, I PNO-77-000 PDR

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