PNO-I-97-024, on 970422,Oyster Creek Nuclear Generating Station Commenced Controlled Shutdown of Unit Due to Equipment Problems.Unit Expected to Be Shut Down for Six Days for Correction of Diaphram Problem

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PNO-I-97-024:on 970422,Oyster Creek Nuclear Generating Station Commenced Controlled Shutdown of Unit Due to Equipment Problems.Unit Expected to Be Shut Down for Six Days for Correction of Diaphram Problem
ML20137Z111
Person / Time
Site: Oyster Creek
Issue date: 04/23/1997
From: Eselgroth P, Stephen Pindale
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
To:
References
PNO-I-97-024, PNO-I-97-24, NUDOCS 9704230359
Download: ML20137Z111 (1)


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,o April 23, 1997 l PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PNO-I-97-024 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 Region I staff in King of Prussia, Pennsylvania on this date. l Facility Licensee Emercency Classification Gpu Nuclear Corp. Notification of Unusual Event Oyster Creek 1 Alert Forked River,New Jersey Site Area Emergency Dockets: 50-219 General Emergency X Not Applicable

Subject:

OYSTER CREEK EQUIPMENT FORCED SHUTDOWN On April 22, 1997, Oyster Creek Nuclear Generating Station commenced a controlled shutdown of the unit due to equipment problems. The licensee entered a limiting condition for operation (LCO) based on Technical Specification 3.0.A due to an identified problem with slow control rod insertion (scram) times. Evaluation of scram time testing data performed during the power reduction over the past weekend revealed that the travel time for a reference sample (7 control rods out of 137) was above the l

Technical Specification criteria. The control rods inserted too slowly  ;

for the first 5 percent of rod insertion (average of 7 control rods was '

O.404 seconds). The maximum average insertion time allowed by the Technical Specification across all of the rods for 5 percent insertion is 0.375 seconds. Further testing of more rods also indicated an average insertion time above the Technical Specification allowable time. The slow insertion times were believed to be caused by Viton diaphragms in the scram solenoid pilot valves that had replaced Buna N diaphragms as an equipment upgrade several years ago. Testing of the control rod reference sample (performed quarterly) was initiated due to a known, industry-wide problem with Viton diaphragms that is currently under review. The unit is expected to be shut down for six days for correction of the diaphragm problem.

The resident inspectors will continue to evaluate the licensee's activities.

The. licensee has issued a press release. The State of New Jersey has been informed.

Contact:

ESELGROTH, PETE PINDALE, STEPHEN (610)337-5234 (609)935-3580 9704230359 970423 PDR I&E PNO-I-97-024 PDR h

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