ML20217A331

PNO-78-200:on 781129,plant Encountered Helium Circulator Auxiliary,Buffer-Mid-Buffer Mismatch.Cause by Opening of Low Pressure Separator Safety Relief Valve Which Released Quantity of Reactor Coolant

ML20217A331
Person / Time
Site:	Fort Saint Vrain
Issue date:	12/01/1978
From:	Klingler G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
To:
References
PNO-78-200, NUDOCS 9804220236
Download: ML20217A331 (1)

Text

fD(2CJO~(.: (d y PRELIMINARY NOTIFICATION h} f>? g Deceq1ber 1, 1978

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PRELI.MINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-78-200 This preliminary notification constitutes EARLY notice of 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: Public Service Company of Colorado Fort St. Vrain Nuclear Power Plant Platteville, Colorado DN 50-267

SUBJECT:

RELEASE OF REACTOR COOLANT TO THE REACTOR BUILDING At approximately 4:00 p.m., November 29, 1978, the Fort St. Vrain plant encountered a Helium Circulator Auxiliary, Buffer-Mid-Buffer mismatch. The trip of two Helium Circulators, trip of the main turbine and manual trip of the reactor followed. Shortly thereafter, the radiation monitors in the Reactor Building indicated elevated radiation levels and personnel were evacuated, at 4:05 p.m., from the Reactor Building portion of the Fort St. Vrain complex. Stack monitoring instrumentation indicated a negligible release. The cause of the increased radiation level in the Reactor Building was determined to have been caused by the opening of a m Low Pressure Separator Safety Relief Valve which released a quantity of m reactor coolant. The Reactor Building radiation levels were back to normal at 9:30 a.m. on s November 30, 1978 and personnel re-cntry was permitted. . , No overexposure or contamination to personnel resulted from the reactor, coolant release. The Public Service Company of Colorado provided information relating to this event to the Colorado State Department of Health and also made a local press release. Region IV first became aware of this condition at 10:45 a.m. on December 1, 1978 during a telephone conversation with NRR. m

Contact:

GKlingler, IE x28019

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O Distribution: TransmittedHSt.Slf/' .. m Chairman Hendrie Commissioner Bradford S. J. Chilk, SECY b Commissioner Kennedy Commissioner Ahearne C. C. Kammerer, CA I i j @CommissionerGilinsky (For Distribution) l l NWN ! $ M Transmitted: MNBB M i'/ P. Bldg Y i'.~d J. G. Davis, IE I Q' 7 L. V. Gossick, EDO 11. R. Denton , NRR Region f d_ p r2- l oro S. H. Hanauer, ED0 R. C. DeYoung, NRR

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