05000339/LER-1980-035-03, /03L-0:on 800715,rod E-5 Position Indication Observed Greater than 12 Steps from Control Rod Demand Position.Caused by Instrument Drift.Rod Position Channel Recalibr

/03L-0:on 800715,rod E-5 Position Indication Observed Greater than 12 Steps from Control Rod Demand Position.Caused by Instrument Drift.Rod Position Channel Recalibr

ML19330C449
Person / Time
Site:	North Anna
Issue date:	08/04/1980
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19330C441	List: 05000339/LER-1980-035, Forwards LER 80-035/03L-0 05000339/LER-1980-035-03, /03L-0:on 800715,rod E-5 Position Indication Observed Greater than 12 Steps from Control Rod Demand Position.Caused by Instrument Drift.Rod Position Channel Recalibr
References
LER-80-035-03L-01, LER-80-35-3L-1, NUDOCS 8008080391
Download: ML19330C449 (2)

LER-1980-035, /03L-0:on 800715,rod E-5 Position Indication Observed Greater than 12 Steps from Control Rod Demand Position.Caused by Instrument Drift.Rod Position Channel Recalibr

Event date:
Report date:
3391980035R03 - NRC Website

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g L R REGULATORY COMMISSION V

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

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/0/5/0/0/0/3/3/9/ (7)

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(8) / O/ 8/ C/ 4/ 8/ 0/ (9)

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

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On July 15, '1980 Unit 2 was operating in Mode 3, and startup operations wete.__/

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in'proaress when the Control Room Operator observed that the Individual Rod

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Position Indication for rod E-5 in shutdown Bank B was greater than 12 steps

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from the control rod demand position. The operator immediately opened the

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reactor trip system breakers in accordance with T.S. 3.1.3.3, and consequently /

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the health and safety of public were not affected. This caent is reportable

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pursuant to 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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/I/D/ (11) /E/ (12) /E/ (13) /I/N/S/T/R/U/ (14) g/ (15)

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

CODE TYPE NO.

-(17) REPORT 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

/E/ (18) /Z/ (19)_ /Z/-(20) /Z/ (21) /0/0/0/0/ (22) /_Y/ (23) /N/ (24) /N/ (25) /W/1/2/0/ (26)

CAUSE DESCRIPTION AND CORRECTIVE ACTIONS (27)

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The cause of this discrepancy was attributed to instrument drift. This is a

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recurring problem with the rod position indication system. The rod position

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channel was recalibrated. No further corrective actions are required.

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FACILITY METHOD OF STATUS

% POWER-~

OTHER STATUS DISCOWRY DESCRMION (32)

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./B/ (28) _/0/0/0/.(29) /

NA

/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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PERSONNEL EXPOSURES NUMBER TYPE.

DESCRIPTION (39)

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' PERSONNEL INJURIES -

NUMBER.

DESCRIPTION

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/1/8/ /0/0/0/ (40) /

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LOSS OF OR DAMAGE TO FACILITY (43)

TYPE DESCRIPIION J/1/9/

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PUBLICITY 1

ISSUED

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NRC USE ONLY

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NAME OF PREPARER V. R. CARTWRIGHT

. PHONE.

(703) 894-5151

SD0anoJN-i

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Virginia Electric and Power Company North Anna Power Station, Unit 2 Attachment: Page 1 of 1 Docket No. 50-339 Report No. LER 80-035

Description of Event

On July 15, 1980 Unit 2 was operating in Mode 3, and start up operations were in progress when the Control Room Operator observed that the Rod Position Indication for rod E-5 was greater than 12 steps from the control rod demand position.

Probable Consequences of Event Since the operator immediately opened the reactor trip system breakers the health and safety of the public were not affected.

Cause of Event

The cause of the rod position indicator drift is attributed to instrument drift which can be caused by changes in the temperature of the rod drive line, changes in the frequency of the excitation source, and by changes in secondary loadings.

Immediate Corrective Action

The rod position indicator channel was recalibrated.

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

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

Generic Implications Rod position indicator drift is a generic problem with the Westing-house rod position indication system. This system is used for North Anna Units 1 and 2.

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