ML19274E794

LER 79-038/03L-0 on 790323:axial Flux Difference Outside 5% Target Band Due to Shutdown in Progress.Flux Difference Was Restored to Normal Range within Three Minutes by Boration

ML19274E794
Person / Time
Site:	North Anna
Issue date:	04/18/1979
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19274E780	List: ML19274E779 ML19274E785 ML19274E787 ML19274E790 ML19274E794
References
LER-79-038-03L, LER-79-38-3L, NUDOCS 7904240421
Download: ML19274E794 (2)

Text

NHC F ORM 360 U. 5. NUCLE AH REGULATORY COMMISSION (7 77) .

LICENSEE EVENT REPORT (PLE ASE PRINT OR TYPE ALL HEQUIRED INFORMATION)

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Total time out of the l o 4 l required band was 3 minutes. A total of 3 penalty deviations minutes were accumulated; ns,j l The health and safety of the general public were not affected. This event is [

o o I reportable as per T.S. 6.9.1.9.b.

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43 44 47 CAUSE DESCRIPTION AND COHHECTIVE ACTIONS h 1: 101 l The axial flux diffgrenneJting out of .its target band was. due tn tho I

. i I shutdown in proqress. Immediate corrective action was ta_ restore the axial fluy I ii12i differencc to within its band within 3 min._.by_bora. tion.

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Virginia Electric and Power Company North Anna Power Station, Unit #1

Attachment:

Page 1 of 1 Docket No. 50-338 Report No. 79-38/03L-0 Description of Event On 3-23-79 during a shift from Mode I to Mode II' operation, the axial flux difference (AFD) was noticed to be outside t:1e 1 5% target band established by T.S. 3.2.1. Actions were immediately taken to restore the AFD within its band. The total time the AFD was out of its band was 3 minutes.

Probable Consequence of Occurrence Axial flux indication is used to monitor in core flux shapes and to ensure abnormal flux shapes do not occur which could lead to exceeding hot channel factors. If AFD is outside its target band, operational restrictions are placed on plant operations. None of these operating restrictions were exceeded, therefore the health and safety of the general public were not affected.

Cause The cause for AFD exceeding its target band limits was the reactor shutdown that was in progress.

Immediate Corrective Actions Returned AFD to within its, target band within 3 minutes by boration.

Scheduled Corrective Actions No further action required.

Action Taken to Prevent Recurrence No action required.

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