05000338/LER-1981-033-03, /03L-0:on 810504,individual Rod Position Indicator D-10 Showed Disagreement of Greater than 12 Steps from Group Demand Position.Caused by Instrument Drift.Channel Recalibr

/03L-0:on 810504,individual Rod Position Indicator D-10 Showed Disagreement of Greater than 12 Steps from Group Demand Position.Caused by Instrument Drift.Channel Recalibr

ML19347F863
Person / Time
Site:	North Anna
Issue date:	05/20/1981
From:	VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19347F861	List: 05000338/LER-1981-033, Forwards LER 81-033/03L-0 05000338/LER-1981-033-03, /03L-0:on 810504,individual Rod Position Indicator D-10 Showed Disagreement of Greater than 12 Steps from Group Demand Position.Caused by Instrument Drift.Channel Recalibr
References
LER-81-033-03L-01, LER-81-33-3L-1, NUDOCS 8105260481
Download: ML19347F863 (2)

LER-1981-033, /03L-0:on 810504,individual Rod Position Indicator D-10 Showed Disagreement of Greater than 12 Steps from Group Demand Position.Caused by Instrument Drift.Channel Recalibr

Event date:
Report date:
3381981033R03 - NRC Website

text

pJ U.S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT CONTROL BLOCK / / / / / / / (1)

(PLEASE PRIN* OR TYPE ALL REQUIRED INFORMATION)

/0/1/

/V/A/N/A/S/1/ (2)

/0/0/-/0/0/0/0/0/-/0/0/ (3)

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

/ / / (5)

LICENSEE CODE LICENSE NUMBER LICENSE TYPE CAT

/0/1/

g/ (6)

/0/5/0/0/0/3/3/8/ (7)

/0/5/0/4/8/1/ (8) [0 /5 /2 /0 /8 /1/ (9)

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

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On May 4, 1981 while in Mode 1 operation, the individual rod position indicator /

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for control rod D-10 showed that this rod was greater than 12 steps from group /

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demand position. This m nt is contrary to T.S. 3.1.3.2.

Since the control

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rod position indication was restored to service within 8 hotirs, the health and /

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safety of the public were not affected. This item is reportable pursuant to

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T.S. 6.9.1.9.b.

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SYSTEM

CAUSE

CAUSE COMP.

VALVE CODE CODE SUBCODF COMPONENT CODE SUBCODE SUBCODE

/0/9/

/I/F/ (11) /E/ (12) [E/ (13) /I/N/S/T/R/U/ (14) g/ (15) g/ (16)

SEQUENTIAL OCCURRENCE REPORT REVISION

_ J.ER/R0 EVENT YEAR REPORT NO.

CODE TYPE NO.

(17) REPORT NUMBER

/8/1/

[-/ /0/3/3/

/\\/

/0/3/

/L/

/-/

g/

ACTION FUTURE EFFECT SHUTDOWN ATTACHMENT NPR6-4 PRIME COMP. COMPONENT TAKEN ACTION ON PLANT METHOD HOURS SUBMITTED FORM SUB. SUPPLIER MANUFACTURER

/E/ (18) /Z/ (19) g/ (20) g/ (21) /0/0/0/0/ (22) g/ (23) /N/ (24) /N/ (25) /w/1/2/0/ (26)

CAUSE DESCRIPTION AND CORRECTIVE ACTIONS (27)

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The cause of this indicator disagreement was instrument drift. The channel

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was recalibrated and returned to service.

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FACILITY METHOD OF STATUS

% POWER OTHER STATUS SCOE RY DISCOERY DESCRIPTION (32)

/ (30) g/ (31)

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OPERATOR OBSERVATION

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/1/5/

g/ (28)

/1/0/0/ (29) /

NA ACTIVITY CONTENT PELEASED OF RELEASE AMOUNT OF ACTIVITY (35)

LOCATION OF RELEASE (36)

/1/ 6.'

/2/ (33)

/Z/ (34) /

NA

/

/

NA

/

PERSONNEL EXPOSURES NUMBER TYPE DESCRIPTION (39)

/1/7/ /0/0/0/ (37) /Z/ (38) /

NA

/

PERSONNEL INJURIES NUMBER DESCRIPTION (41)

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

NA

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LOSS OF OR DAMAGE TO FACILITY (43)

TYPE

DESCRIPTION

/1/9/

/Z/ (42) /

NA

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PUBLICITi ISSUED DESCRIPTION (45)

NRC USE ONLY

/2/0/

[NL (44) /

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8105260481

Virginia Electric and Power Company North Anna Power Station, Unit #1 Attachment: Page 1 of 1 Docket No. 50-338 Report No. LER 81-033/03L-0

Description of Event

On May 4, 1981 during steady state power at 100%, the Individual Rod Position Indicator D-10 showed a disagreement of greater than 12 steps from the group demand position. This event is contrary to T.S. 3.1.3.2.

Probable Consequences of Occurrence Operability of the control rod position indication is required to determine control rod position and thereby ensure compliance with control rod alignment and insertion limits.

Since the control rod was not misaligned and the position indication restored as required by T.S. 3.1.3.2, the health and safety of the public were not affected.

Cause of Event

1 The cause of the disagreement between individual rod position and group demand positicn was instrument drift in the IRPI channel.

Immediate Corrective Action

The channel was recalibrated and returned to service within the requirements of the action stotement.

Scheduled Corrective Action A long term investigation into the problems associated with the IRPI system is in progress. No further corrective action is scheduled until an adequate design modification is developed and proved effective.

Actions Taken to Prevent Recurrence No further action is required at this time.

Generic Implications Indicator drift is a generic problem with the Westinghouse IhPI system. This system is used for North Anna Units 1 and 2.