PNO-IV-98-001A, on 980105,plant Shutdown When Heavy Rains Caused Accumulation of Debris at Circulating & Svc Water Intake Structure.Debris Damaged Some Intake Structure Components.Repairs to Intake Components Completed on 980109

PNO-IV-98-001A:on 980105,plant Shutdown When Heavy Rains Caused Accumulation of Debris at Circulating & Svc Water Intake Structure.Debris Damaged Some Intake Structure Components.Repairs to Intake Components Completed on 980109

ML20198M016
Person / Time
Site:	Arkansas Nuclear
Issue date:	01/13/1998
From:	Collins E, Kennedy K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
To:
References
PNO-IV-98-001A, PNO-IV-98-1A, NUDOCS 9801160170
Download: ML20198M016 (1)

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^J:nu'ry 13,1998 l PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE

, .PNO-IV-98-001 A .s 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 l and is basically a.Il that is known by Region IV staff in Arlington, Texas on thic rl3te.

Facility Licensee Emeraency Clar,sification Entergy Operations, Inc. Notification cf Unusual Event Arkansas Nuclear i Alert Russelville, Arkansas Site Area Emergency Dockets: 50-313 Generai Emergency X Not Applicable

Subject:

UPDATE ON UNPLANNED PLANT SHUTDOWN GREATER THAN 72 HOURS Arkansas Nuclear One, Unit 1, was retumed to pcwer operation on January 13.1998.The plant was shutdown on January 5,1998, when heavy rains caused an accumulation of debris at the circulating and service water intake structure. The debris damaged some intake structure components. The unit shutdown period was extended when one control rod would not reinsert past the 5 percent withdrawn position, and then the control rod became unmovable. The rod was located on the periphery of the core. Repairs to damaged intake structure components were completed on January 9.

Licensee personnel were subsequently successful in moving the control rod, but were not successful in fully reinserting the control rod. The control rod would not reinsert past the 5 percent withdrawn position and licensee personnel declared the control rod inoperable.

The most probable cause of the failure to fully reinsert the control rod is foreign material in the hydraulic snubber region of the control rod drive mechanism. On January 12, a conference call was conducted between licensee personnel and the NRC staff to discuss startup and subsequent operation with one inoperable control rod. Operation with one inoperable control rod is an analyzed condition and allowed by the operating license, with certain added surveillance test requirements for the remaining control rods. The rod is fully withdrawn and would be expected to insert to the 5 percent withdrawn position in the event of a reactor trip. Reactor shutdown capability is fully maintained in this configuration.

The NRC resident inspection staff monitored reactor startup activities Region IV received

. notification of the occurrence by telephone from the Senior Resident inspector at 7:30 a.m. (CST) on January 13,1998.

~ Region IV has informed OEDO, PAO, and NRR.

This information has been discussed with the licensee and is current as of 7:30 a.m. on January 13,1998.

The. state of Arkansas has been informed.

Contact:

Elmo Collins Kriss Kennedy (817)860-8291 (501)968-3290 o

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9801160170 980113 ll-ll

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PDR I&E PHO-IV-90-001A PDR _ - _____-____ - - _ -