05000339/LER-1981-031-03, /03L-0:on 810404,axial Flux Difference Deviated Greater than 5% from Target for Max 1-minute Duration During Power Increase Following Reactor Trip.Caused by Xenon Transient During Recovery from Reactor Trip

/03L-0:on 810404,axial Flux Difference Deviated Greater than 5% from Target for Max 1-minute Duration During Power Increase Following Reactor Trip.Caused by Xenon Transient During Recovery from Reactor Trip

ML20003H728
Person / Time
Site:	North Anna
Issue date:	04/30/1981
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20003H726	List: 05000339/LER-1981-031, Forwards LER 81-031/03L-0 05000339/LER-1981-031-03, /03L-0:on 810404,axial Flux Difference Deviated Greater than 5% from Target for Max 1-minute Duration During Power Increase Following Reactor Trip.Caused by Xenon Transient During Recovery from Reactor Trip
References
LER-81-031-03L, LER-81-31-3L, NUDOCS 8105070340
Download: ML20003H728 (2)

LER-1981-031, /03L-0:on 810404,axial Flux Difference Deviated Greater than 5% from Target for Max 1-minute Duration During Power Increase Following Reactor Trip.Caused by Xenon Transient During Recovery from Reactor Trip

Event date:
Report date:
3391981031R03 - NRC Website

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g LICENSEE EVENT REPORT CONTROL BLOCK / / / / / / / (1)

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DOCKET NUMBER EVENT DATE REPORT DATE EVENT DESCRIPTION AND PROBABLE CONSEQUENCES (10)

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/ On April 4, 1981, with the Unit in Mode 1, the Axial Flux Difference deviated

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/ greater than 5% from the target for a maximum one minute duration while return- /

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/ ing to power following a reactor trip. Since the Axial Flux Difference was

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/ restored within the operating band within the time required by the Action State- /

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/ ment (15 minutes), the health and safety of the general public were not affected./

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/ This is contrary to T.S. 3.2.1 and reportable pursuant to T.S. 6.9.1.9.b.

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SYSTEM

CAUSE

CAUSE COMP.

VALVE CODE CODE SUBCODE COMPONENT CODE SUBCODE SUBCODE

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SEQUENTIAL OCCURRENCE REPORT REVISION LER/R0 EVENT YEAR REPORT NO.

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ACTION FUTURE EFFECT -/-/ /0/3/1/ /\\/

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SHUTDOWN ATTACHMENT NPRD7 PRIME COMP. COMPONENT TAKEN ACTION ON PLANT METHOD HOURS SUBMITTED FORM SUB. SUPPLIER MANUFACTURER

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CAUSE DESCRIPTION AND CORRECTIVE ACTIONS (27)

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/ The Axial Flux Difference was affected by a Xenon transient during a recovery

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/ from a reactor trip. The problem was alleviated by inserting the control rods

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/ into the core until the Axial Flux Difference was within the required band. The /

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/ plant was returning to full power when the Axial Flux Difference was outside of /

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/ the target band.

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FACILITY METHOD OF STATUS

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PUBLICITY ISSUED DESCRIPTION (45)

NRC USE ONLY

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NAME OF PREPARER W. P. CARTWRIGHT PHONE (703) 894-5151 81050703YO

Virginia Electric and Power Company North Anna Power Station, Unit 2 Attachment: Page 1 of 1 Docket No. 50-339 Report No. LER 81-031/03L-0

Description of Event

On April 4,_1981, with the unit at 94% power the Axial Flux Difference deviated greater than 5% from the target for a maximum one minute duration during a power increase following a reactor trip.

Probable Consequences of Occurrence The Axial Flux Difference was restored within the operating band within the time specified by the Action Statement. The health and safety of the general public were not affected.

Cause of Event

The Axial Flux Difference was affected by a Xenon transient during a recovery from a reactor trip. The plant was returning ~to full power when the Axial Flux Difference was outside of the target band.

Immediate Corrective Action

The operator inserted the control rods into the reactor core until the Axial Flux Difference was within the operating band specified by T.S. 3.2.1.

Scheduled Corrective Action There are no scheduled corrective actions.

Actions Taken to Prevent Recurrence No action is needed to prevent recurrence.

l Generic Implications There are no generic implications.

l t

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