05000339/LER-1980-084-03, /03L-0:on 801027-29,differential of Greater than 12 Steps Discovered Between Rod Position Indication for Rod Cluster J-3 & Demand Position.Caused by Instrument Drift. Channel Recalibr

/03L-0:on 801027-29,differential of Greater than 12 Steps Discovered Between Rod Position Indication for Rod Cluster J-3 & Demand Position.Caused by Instrument Drift. Channel Recalibr

ML19345B428
Person / Time
Site:	North Anna
Issue date:	11/19/1980
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19345B427	List: 05000339/LER-1980-084, Forwards LER 80-084/03L-0 05000339/LER-1980-084-03, /03L-0:on 801027-29,differential of Greater than 12 Steps Discovered Between Rod Position Indication for Rod Cluster J-3 & Demand Position.Caused by Instrument Drift. Channel Recalibr
References
LER-80-084-03L, LER-80-84-3L, NUDOCS 8012010280
Download: ML19345B428 (2)

LER-1980-084, /03L-0:on 801027-29,differential of Greater than 12 Steps Discovered Between Rod Position Indication for Rod Cluster J-3 & Demand Position.Caused by Instrument Drift. Channel Recalibr

Event date:
Report date:
3391980084R03 - NRC Website

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y p-O U.S. NUCLEAR' REGULATORY COMMISSION LICENSEE EVENT REPORT CONTROL BLOCK /'/ / / / / / (1)

(PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION)

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/V/A/N/A/S/2/ (2)

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/4/1/1/1/1 (4)

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LICENSEE CODE LICENSE NUMBER LICENSE TYPE CAT 0/1f RE

/L/.(6)

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(8) /1/1/1/9/8/0/ (9) g0 DOCKET NUMBER EVENT DATE REPORT DATE EVENT DESCRIPTION AND PROBABLE CONSEQUENCES (10)

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On three consecutive dates 10-27, 10-28, and 10-29, the Rod Position Indication /

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for rod cluster J-3 (part of shutdown Bank A) differed from the demand position /

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by greater than 12 steps, thereby violating T.S. 3.1.3.2.

Since the channel

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was recalibrated and returned to an operable condition within a few hours the /

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health and safety of the public were not affected.

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4 SYSTEM

CAUSE

CAUSE COMP.

VALVE CODE CODE SUBCODE' COMPONENT CODE SUBCODE SUBCODE 4

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-/I/F/ (11) /E/ (12) /E/ (13) /I/N/S/T/R/U/ (14) [I/ (15)

/_Z/ (16)

SEQUENTIAL OCCURRENCE REPORT' REVISION LER/R0 EVENT YEAR REPORT N0.

CODE TYPE NO.

(17) PIPORT NUMBER

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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

/EL (18) /Z/ (19) [Z[ (20) /Z/ (21) /0/0/0/0/ _(22) [][/ (23) /N/ (24) /N/ (25) /W/1/2/0/'(26)

CAUSE DESCRIPTION AND CORRECTIVE ACTIONS (27)

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The rod position indicator drift is attributed to instrument drift which can be/

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caused by a change in temperature of the rod drive mechanism and therefore may /

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occur during power ascension or a ' rampdown. The corrective action is to recal-/

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ibrate the channel associated with the affected RPI.

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FACILITY METHOD OF STATUS

% POWER OTHER STATUS DISCOVERY DISCOVERY DESCRIPTION (32)

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[C/ (28)

/0/9/6/ (29) /

NA

/ (30) /A/ (31) / Operator Observation

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ACTIVITY CONTENT RELEASED OF RELEASE AMOUNT OF ACTIVITY (35)-

LOCATION OF RELEASE (36)

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NA

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NA

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PERSONNEL EXPOSUPIS NUMBER TYPE.

DESCRIPTION (39)

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' NA

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PERSONNEL INJURIES-NUMBER DESCRIPTION (41)

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NA

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LOSS OF OR DA'1 AGE TO FACILITY (43) 4 TYPE-

DESCRIPTION

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NA

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'PUDLICITY

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ISSUED DESCRIPTION (45)

NRC USE ONLY

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

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o-Virginia Electric and Power Company North Anna Power Station, Unit 2 Attachment: Page 1 of I Docker No. 50-339 Report No. LER 80-084/03L-0

Description of Event

On three consecutive dates 10-27, 10-28, and 10-29, the Rod Position Indication for rod cluster J-3 differed from the demand position by greater than 12 steps, thereby violating T.S. 3.1.3.2.

The event is reportable pursuant to T.S. 6.9.1.9.b.

Probable Consequences of Occurrence Since the RPI channel was recalibrated and returned to an operable condition within a few hours the health and safety of the public were not affected.

Cause of Event

The RPI drift is attributed to instrument drift which can be caused by a change in temperature of the control rod drive mechanism and therefore occurs occasionally during changes in reactor power.

Immediate Corrective Action

The immediate corrective action was to recalibrate the RPI channel, and verify that the indicator was restored to a normal operating condition.

Scheduled Corrective Action A long term inrestigation into the problems associated with the rod position indicating sy.' tem is in progress. No further corrective action will be scheduled until an adequate design modification is developed.

Actions Taken to Prevent Reccurrence No actions to prevent recurrence are required.

Generic Implications Rod position indicator drift is a generic problem with the Westinghouse rod position indicating system. This system is in use at North Anna Units 1 and 2.