PNO-IV-88-006, on 880105,licensee Determined That Reactor Vessel Flange Inner O-ring Leaking.Inner Leakoff Monitor Tube Isolated to Contain Leakage.Outage of Approx 21 Days Expected in Order to Replace O-ring Seals

PNO-IV-88-006:on 880105,licensee Determined That Reactor Vessel Flange Inner O-ring Leaking.Inner Leakoff Monitor Tube Isolated to Contain Leakage.Outage of Approx 21 Days Expected in Order to Replace O-ring Seals

ML20148H142
Person / Time
Site:	Waterford
Issue date:	01/22/1988
From:	Tapia J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
To:
References
PNO-IV-88-006, PNO-IV-88-6, NUDOCS 8801270138
Download: ML20148H142 (2)

e January 22, 1988 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE -- PNO-IV-88-06 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information is as initially received without verification or evaluation, and is basically all that is known by the Region IV staff on this date.

FACILITY: Wolf Creek Nuclear Operating Corp. Licensee Emergency Classification:

t!olf Creek Generating Station Notification of Unusual Event Coffey County, Kansas Alert DN: 50-382 Site Area Emergency General Emergency X Not Applicable

SUBJECT:

REACTOR VESSEL FLANGE LEAKAGE During plant startup after the last refueling outage (Mode 1 was attained on January 5,1988), Wolf Creek determined that the reactor vessel flange inner 0-ring was leaking. The inner leakoff monitor tube was then isolated to contain the leakage. As a result of concerns raised at that time by NRC Region IV and NRR technical staff, the licensee committed to closely monitor for leakage from the outer 0-ring and commence an inmediate reactor shut down if any was identified. Subsequently, at 6:30 p.m. CST on January 21, 1988, the licensee determined that the reactor vessel outer 0-ring was leaking, and at 6:58 p.m.

CST, began a shutdown from 100 percent power. At 9:29 p.m. CST, the reactor was manually tripped from 25 percent in accordance with procedures. As of 6:30 a.m.

CST on January 22, 1988, the plant was at 400 F and 1150 psig, continuing to cool down and depressurize to Mode 6 (refueling) in order to pull the reactor vessel head and replace the 0-ring seals. An outage of approximately 21 days is expected in order to replace both 0-ring seals.

The licensee is planning to issue a press release This information has been confirmed with a licensee representative.

CONTACT: J. I. Tapia, (FTS 728-8158)

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