05000339/LER-1980-079-03, /03L-0:on 801017,discovered That on 800918,nuclear Power Range Channels Indicated Power Levels Lower than Determined by Daily Calorimetric Procedure.Caused by Misinterpretation of Acceptance Criteria.Channel Adjusted

/03L-0:on 801017,discovered That on 800918,nuclear Power Range Channels Indicated Power Levels Lower than Determined by Daily Calorimetric Procedure.Caused by Misinterpretation of Acceptance Criteria.Channel Adjusted

ML19340C484
Person / Time
Site:	North Anna
Issue date:	11/10/1980
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19340C479	List: 05000339/LER-1980-079, Forwards LER 80-079/03L-0 05000339/LER-1980-079-03, /03L-0:on 801017,discovered That on 800918,nuclear Power Range Channels Indicated Power Levels Lower than Determined by Daily Calorimetric Procedure.Caused by Misinterpretation of Acceptance Criteria.Channel Adjusted
References
LER-80-079-03L-01, LER-80-79-3L-1, NUDOCS 8011170478
Download: ML19340C484 (2)

LER-1980-079, /03L-0:on 801017,discovered That on 800918,nuclear Power Range Channels Indicated Power Levels Lower than Determined by Daily Calorimetric Procedure.Caused by Misinterpretation of Acceptance Criteria.Channel Adjusted

Event date:
Report date:
3391980079R03 - NRC Website

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T LICENSEE EVENT REPORT CONTROL BLAC" / / / / / / / (1)

(PLEASE PRINT OR TYPE ALL REQUIBiD INFORMATION)

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LICENSEE CODE LICENSE NUMBER LICENSE TYPE CAT

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

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On October 17, 1980, review by the performance group discovered that on 9-18-80/

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the nuclear power range channels indicated lower t aan the power level determin-/

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ed by the daily calorimetric and were not adjusted to within +2,-0% as required /

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by T.S. 4.3.1.

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Because the unit was operating at less than 50% power at

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the time and the overpower trip was set at 60%, the health and safety of the

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general public were not affected. This event is reportable pursuant to

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T.S. 6.9.1.9.c.

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SYSTEM

CAUSE

CAUSE COMP.

VALVE CODE CODE SUBCODE COMPONENT CODE SUBCODE SUBCODE

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Z SEQUENTIAL OCCURPINCE REPORT REVISION LER/R0 EVENT YEAR REPORT NO.

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ACTION FUTURE EFFECT SHUTDOWN ATTACHMENT NPRD-4 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 Shift Supervisor misinterpreted the PT acceptance criteria and adjusted the/

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NI's to within - 2. 3% of the heat balance. The power range channels were

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properly adjusted the following day as part of the daily calorimetric proce-

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dure.

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FACILITY METHOD OF STATUS

%IOWER OTHER STATUS DISCOVERY DISCOVERY DESCRIPTION (32)

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[B/ (28)

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NA

/ (30) /B/ (31) / Periodic Test Review /

ACTIVITY CONTENT RELEASED OF RELEASE AMOUNT OF ACTIVITY (35)

LOCATION OF RELEASE (36)

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PERSONNEL EXPOSURES NUMBER TYPE DESCRIPTION (39)

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PERSONNEL INJURIES NUMBER DESCRIPTION (41)

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LOSS OF OR DAMAGE TO FACILITY @3)

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PUBLICITY ISSUED

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NRC USE ONLY

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.NAME OF PREPARER W. R. CARTWRIGHT PHONE (703) 894-5151 801117o

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Virginia Electric and

• ar Company North Anna Power Stat.

2, Unit 2 Attachment: Page 1 of 1 Docket No. 50-339 Report No. LER 80-079/03L-0 Description of rac On October 17, 1980, routine periodic test review discovered that on September 18, 1980 the nuclear power range channels were indicating lower than the power level determined by the daily calorimetric and were not adjusted to within +2,-0% as required by T.S. 4.3.1.1.1.

The channels as left indicated 48, 49.8, 47.9, and 47.3% power while the heat balance indicated-plant power at 49.9%. This event is reportable pursuant to T.S. 6.9.1.9.c.

Probable Consecuences of Occurrence The purpose of the power range channels is to provide fuel rod rating protection by tripping the reactor on overpower (high neutron -

flux). The channels are also used to trip the reactor when an abnormal rate of increase or decrease in nuclear power occurs in two out of four channels. When operating above 15% power, each power range channel of the nuclear instrumentation system is calibrated daily against a heat balance standard. Because on September 18 the-unit was operating at less than 50% power and the nuclear overpower trip was set at 60%, the health and safety of the general public were not affected.

Cause of Event

The Shift Supervisor misinterpreted the PT acceptance criteria and adjusted the NI's to within -2.0% of the heat balance. The 47.8% as left reading was a simple error on the part of the operator performing the PT.

Immediate Corrective Action

- ' Esch nuclear power range channel was properly ' adjusted the following A'

day as part of the daily calorimetric procedure.

Scheduled Corrective Action No scheduled corrective action is required.

Actions Taken'to Prevent Recurrence No further actions are required.

Generic Implications-None.

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