05000338/LER-1979-075-03, /03L-0 on 790604:during Steady State Operation, Axial Flux Difference Deviated Over 5% from Target for Two Minutes,Contrary to Tech Specs.Caused by Xenon Oscillation Initated by Rod Operability Test.Power Reduced by 2%

/03L-0 on 790604:during Steady State Operation, Axial Flux Difference Deviated Over 5% from Target for Two Minutes,Contrary to Tech Specs.Caused by Xenon Oscillation Initated by Rod Operability Test.Power Reduced by 2%

ML19269E518
Person / Time
Site:	North Anna
Issue date:	06/27/1979
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19269E509	List: 05000338/LER-1979-075-03, /03L-0 on 790604:during Steady State Operation, Axial Flux Difference Deviated Over 5% from Target for Two Minutes,Contrary to Tech Specs.Caused by Xenon Oscillation Initated by Rod Operability Test.Power Reduced by 2% 05000338/LER-1979-080-03, /03L-0 on 790608:during Power Escalation,Axial Flux Difference Deviated More than +5% from Target for 16 Minutes,Contrary to Tech Specs.Caused by Withdrawal of Control Rods 05000338/LER-1979-081-03, /03L-0 on 790608:individual Rod Position Indicators M-10 & D-10 Placed in Test Status,Contrary to Tech Specs.Caused by Repair Work to Remove Previously Installed Jumper.Calibr Performed ML19269E508
References
LER-79-075-03L, LER-79-75-3L, NUDOCS 7906290205
Download: ML19269E518 (2)

LER-1979-075, /03L-0 on 790604:during Steady State Operation, Axial Flux Difference Deviated Over 5% from Target for Two Minutes,Contrary to Tech Specs.Caused by Xenon Oscillation Initated by Rod Operability Test.Power Reduced by 2%

Event date:
Report date:
3381979075R03 - NRC Website

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REPOH T O ATE 80 EVENT DESCRIPTION AND PRO 3 ABLE CONSEQUENCES lDuring steady state operation, the Axial Flux Difference deviated greater than 5% from g o

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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. LER 79-075/03L-0

Description of Event

On 6-4-79 during steady state operation, the Axial Flux Difference deviated greater than -5% from the target for a 2 minute duration.

This is contrary to T.S. 3.2.1.

The AFD was returned to within the target band within the 15 minute allowance of Action Statement a.1 of T.S. 3.2.1.

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 affected.

There are no generic implications for Unit #2.

Cause of Occurrence The AFD deviation was a xenon oscillation which was initiated by a rod operability test.

Immediate Corrective Action

An RCS boration and a power reduction of 2% was the action taken to restore the AFD to within the target band.

Scheduled Corrective Action Surveillance of the xenon oscillation was continued to prevent further AFD deviations.

Actions Taken To Prevent Recurrences No further actions are required.

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