ML20151X634

PNO-77-176:on 771006,safety Relief Valves Failed to Operate After Reactor Tripped from 90% Power as Result of Error by Instrument Technician.Reactor Placed in Cold Shutdown Condition to Remove & Retest Suspect Valves

ML20151X634
Person / Time
Site:	Hatch
Issue date:	10/07/1977
From:	Klingler G, Sniezek J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
To:
References
PNO-77-176, NUDOCS 9809170188
Download: ML20151X634 (1)

Text

-f$ Ob4%>W W) /W j/ th] PRELIMINARY NOTIFICATION  ! r

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October 7, 1977 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-77-73-- This preliminary notification constitutes EARLY notice of an event of F65TIBLE 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: Georgia Power Company s Hatch. Unit No. 1 *

                                                                                        .                        l Docket No. 50-321 Baxley, Georgia      '

SUBJECT:

FAILURE OF SAFETY RELIEF VALVES TO OPERATE l The reactor tripped from 90 percent power at 11:37 a.m. on October 6 as a result of an error by an instrument technician. Fourteen seconds after the trip, the main steam isolation valves cle' ,. proximately eight minutes after the reactor trip, one safety reliet valve (SRV) opened at 1100-1105 psig as indicated on the wide range pressure recorder. At

    }       1100 psig, four additional SRV's should have opened, and the remaining j       six SRV's probably should have opened.            .

f The licensee has determined that these valves are operable manually, but i

   ;        has not, determined why the valves did not operate at the required                                   l settings. The reactor has been placed in cold shutdown condition to remove and retest all suspect valves. The plant will be shutdown at                                  '

least four days. ,_ Media interest is not expected. Neither Region-II nor the licensee . . plans a news release. The State of Georgia has been notified. Region II (Atlanta) received notification of this occurrence by tele-phone from Assistant Plant Manager at 8:50 p.m. on October 6. This f infonnation is current as of 1 p.m. on October 7. 3 ,'

Contact:

GKlingler, IE x28019 JSniezek, IE x28019 4 i TransmittedHSt#f.CL; O Distribution: Chairman Hendrie Commissioner Bradford - ~7 Commissioner Kennedy S. J. Chilk, SECY C. C. Kammerer, CA l Commissioner Gilinsky (ForDistribution) Transmitted: MNBB_f O' P Bldg ff f4 E. Volgenau, IE L. V. Gossick, EDO' E. G. Case, NRR Region g 1,'f f S. H. Hanauer, EDO J. J. FoucharA PA SSBldg88I.- (MAIL) W. G. McDonal', M FC C. V. Smith, NMSS R. J. McTiernan, OIA _ R. G. Ryan, Ob> R. Minogue, SD { H. K. Shapar, ELD . PRELIMINARY NOTIFICATION 9009170188 771007 PDR IkE PNO-77-176 PDR ,

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