ML20249B537

PNO-76-120:on 760715,Brunswick Unit 2 Sustained Inadvertent Partial Blowdown.Licensee Plans to Inspect Both Pilot Valves of Two Valves Affected Prior to Restart.Reactor Will Be Shutdown Over Weekend in Order to Complete Valve Checkout

ML20249B537
Person / Time
Site:	Brunswick
Issue date:	07/16/1976
From:	Gower G, Roy G, Thompson D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
To:
References
PNO-76-120, NUDOCS 9806230277
Download: ML20249B537 (1)

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[ PRELIMINARY NOTIFICATION

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July 16, 1976

-PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-76-120 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

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and is basically all that is known by IE staff on this date.

. Facil,ity: Brunswick Unit 2, Carolina Power and Light-

Subject:

- Inadvertent Partial Blowdown at Brunswick Unit 2 The IE:II inspector at the site informed the Region II office that Brunswick Unit 2 sustained an inadvertent partial blowdown on July 15 at about 0800.

Spurious operation of one Target Rock relief valve during operation at 20% power resulted in a reactor pressure decrease. The operator ,

checked the temperature recorder containing the relief valve ta11 pipe

. thermocouple and erroneously selected another relief valve to open for the purpose of reseating the valve. During the resulting pressure loss with two valves open, the reactor pressure decreased from 933 psig to 450 psig. The main steam isolation valves closed due to the pressure

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! decrease and the reactor scrammed.

Subsequently the relief valve which initially opened was determined to have been weeping previously. The licensee plans to inspect both pilot valves of the-two valves affected prior to restart. It is expected that the reactor will be shutdown over the weekend in order to complete neces-sary checkout of these valves.

The Region II inspector is onsite reviewing the occurrence. No press release is planned by either the licensee or Region II.

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Contact:

GCGower, IE x27261 GWRoy, IE x27261 DThompson, IE x27541 i

Distribution: *

! Chairman Rowden Commissioner Mason S. J. Chilk, SECY Commissioner Gilinsky C. C. Kammerer, CA G. F. Murphy, JCAE j ,, Commissioner Kennedy

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L. V. Gossick, EDO E. Volgenau, OIE J. A. Harris, PA B. C. Rusche, NRR H. K. Shapar, ELD T. J. McTiernan, AIA l K. R. Chapman, NMSS R. G. Ryan, OSP ,

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PRELIMINARY NOTIFICATION

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9806230277 760716 ISE

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