ML20207G635

PNO-77-189:on 771016,following Refueling of Unit 1 & During Startup Physics Testing of Reloaded Core,Measured Values for Ejected Rod Worth Showed an Unexpected Reduction from Predicted Values

ML20207G635
Person / Time
Site:	Oconee
Issue date:	10/25/1977
From:	Klingler G, Nolan F NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
To:
References
PNO-77-189, NUDOCS 9903120133
Download: ML20207G635 (1)

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,, PRELIMINARY NOTIFICATION l October 25, 1977 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-77-189 This preliminary notification constitutes EARLY notice of an 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 as of this date.

FACILITY: Duke Power Company Oconee Unit No. 1

~ seneca, South Carolina

~ Docket No.5~0-269'

SUBJECT:

CORE FLUX TILT FOLLOWING REFUELING Following refueling of Unit No. I and during startup-up physics testing of the reloaded core on October 16, the measured values for ejected rod worth showed an unexpected reduction from predicted values. Evaluation of the worth of symetric rods indicated a radial flux tilt.

Preliminary core power distribution measurements indicated a four percent flux tilt at forty percent power, a reduction from seven percent tilt at fifteen percent power. Additional measurements by the licensee have been unsuccessful in identifying the cause of the tilt. Fuel distribution or a dropped control rod finger have been considered as possible causes. "

Additional core power distribution measurements are planned.for October 26, when forty percent full power xenon equilibrium is reached.

Media interest is not expected. The State of South Carolina is being notified. A press release is not planned by the licensee or NRC. An NRC inspector is at the site to review this matter.

Region II (Atlanta) received notification of this condition by telephone from the licensee at 9:30 a.m. on October 25. This information is current as of 10:00 a.m. on October 25.

Contact:

GKlingler, IE x28019 FNolan, IE x28019 -

Distributioni Transmitted H St II fb ; ~

Chairman Hendrie Comission Bradford Comissioner Kennedy S. J. Chilk, SECY C. C. Kamerer, CA 0-Comissioner Gilinsky (For Distribution) /

Transmitted: MNBB D33 P Bldg /.') [ E. Volgenau, IE L..V. Gossick, EDO E. G. Case, NRR Region i fl) P S. H. Hana0er, EDO ;Vy' J. J.*Fouchard, PA SS B1dg //1 . (MAIL)

W. G. Mcdonald, MIPC . C. V. Smith, NMSS

• R. J. McTiernan, 0IA R. G. Ayan, OSP R. Minogue, SD H. K. Shapar, ELD 9903[205'33 $1025 9 """"" NOTIFICATION PDR 18 E PNO-77-189 PDR

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