ML20248K998

PNO-78-030:on 780213,w/unit Operating at 90% Power One Target Rock Relief Valve Opened & Remained Open Until Reactor Pressure Reduced to 195 Psig.Licensee Inspected Suppression Chamber & Nothing Unusual Found

ML20248K998
Person / Time
Site:	Browns Ferry
Issue date:	02/14/1978
From:	Klingler G, Nolan F, Sniezek J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
To:
References
PNO-78-030, PNO-78-30, NUDOCS 9806100369
Download: ML20248K998 (1)

Text

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k. PRELIMINARY NOTIFICATION February 14, 1978

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PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-78-30 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: Tennessee Valley Authority Browns Ferry, Unit No. 2 Docket No. 50-260 Decatur Alabama

SUBJECT:

PRIMARY SYSTEM BLOWDOWN At 1:25 p.m. on February 13, with the unit operating at 90 percent power, one Target Rock relief valve opened and renined open until reactor '

pressure reduced to 195 psig. The reactor was manually scrammed at 1:50 p.m. when suppression pool temperature reached 110 degrees Fahrenheit.

Suppression pool cooling had been initiated at 1:35 p.m. The licensee inspected the suppression chamber and nothing unusual was found. The ed Technical Specification limiting cooldown rate of 100 degrees Fahrenheit / hour may have been exceeded. A thermal, transient analyses is in process. A similar event occurred on Unit No. 2 February S.1978. . /g

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Media interest is expected due to current interest in nuclear plant problems. i A news release is oeing made by the licensee. NRC does not plan to make ' h, a news release. The State of Alabama has been informed.

f Region II (Atlanta) received notification of this occurrence by telephone y x from the Assistant Plant Superintendent et 6:00 p.m. on February 13.

This information is current as of 10:30 ' m. on February 14. d

Contact:

GK11ngler, IE x28019 FNc- IE x28019 JSniezek, IE x26019 Distribution: TransmittedHSt%((

Chairman Hendrie Commissioner Bradford Commissioner Kennedy S. J. Chilk, SECY C. C. Kammerer. CA

- Commissioner Gilinsky (For Distribution)

Transmitted: MNBB 2 M P Bldg 2: 2P E. Volgen IE L. V. Gossick, EDO E. G. Case, NRR Region 2 x 2 h S. H. Hanauer EDO J. J. Fouchard, PA SS Bldg 2 ',2 3 (MAIL)

R. Hartfield, MIPC C. V. Smith, NMSS T. J. McTiernan, 01A R. G. Ryan, OSP R. Minogue, SD l

H. K. Shapar. ELD

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PRELIMINARY NOTIFICATION 9906100369 790214 PDR ISE PNO-79-030 PDR E-- ______ _ _ _ _ _ _