ML19259B779

LER 79-027/03L-0 on 790225:axial Flux Difference Deviated Greater than 5% from Target.Caused by Xenon Transient Occurring During Startup Operation.Corrected by Boration by Reactor Operator

ML19259B779
Person / Time
Site:	North Anna
Issue date:	03/16/1979
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19259B778	List: ML19259B777 ML19259B779
References
LER-79-027-03L, LER-79-27-3L, NUDOCS 7903230141
Download: ML19259B779 (2)

Text

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8 60 61 DOCKEi NUMBER DATE REPORT DATE EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h O 2 lDuring a routine startup operation, the axial flux difference deviated greater than i o 3 iS% from target. A total of 37 penalty minutes was accumulated, the majority of this i o 4 jtime was below 50% power. Action Statement a.2 of T.S. 3.2.1 allows continued opera- i o ,, tion between 85% and 50% power if the penalty accumulation is less than 60 minutes, i-o o itherefore T.S. 3.2.1 was not violated. This event is reportable as per T.S. 6.9.1.9.b.i s

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43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS i o iThe cause of the AFD Deviation was a Xenon Transient which ocetirred dirrino startun l li li j ioperation. Corrective action was a boration by the Reactor Operator which returned 1

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NAVE OF PREPARER

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

Attachment:

Page 1 of 1 Docket No. 50-338 Report No. LER 79-027/03L-0 Description of Event:

On 2/25/79, during a routine start-up operation, the Axial Flux Difference deviated greater than - 5% from the target, a total of 37 penalty minutes was accumulated.

Action statement a.2 of T.S. 3.2.1 allows continued operation between 85%

and 50% if the penalty accumulation is less than 60 minutes. Therefore, T.S. 3.2.1 was not violated.

This event is reportable as per T.S. 6.9.1.9.b.

Probable Consequences of Occurrence:

Surveillance of the Axial Flux Difference assures that the limits of the heat flux hot channel factor are not exceeded during normal operation or in the event of Xenon redistribution following power changes. This provides protection against exceeding the DNBR and peak fuel clad temperatures.

Since the AFD was returned to its limit within the time allotted, there was no effect upon the safe operation of the plant. As a result, the public health and safety was not endangered.

Cause of Occurrence:

The cause of the AFD deviation was a Xenon transient which occurred during startup operations.

Immediate Corrective Action:

Corrective action was a boration by the reactor operator which returned the AFD to within the target band. Close surveillance of the AFD continued until the plant was returned to full power.

Scheduled Corrective Action:

No further action required.

Actions Taken To Prevent Recurrence:

No further action required.