05000338/LER-1980-057-03, /03L-0:on 800618,during Mode 2 Operation,Greater than Twelve Step Disagreement Was Noted Between Individual & Group Position Indication for Rod G-9.Caused by Voltage Drift in Signal Conditioning Card

/03L-0:on 800618,during Mode 2 Operation,Greater than Twelve Step Disagreement Was Noted Between Individual & Group Position Indication for Rod G-9.Caused by Voltage Drift in Signal Conditioning Card

ML19320C053
Person / Time
Site:	North Anna
Issue date:	07/07/1980
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19320C045	List: 05000338/LER-1980-057, Forwards LER 80-057/03L-0 05000338/LER-1980-057-03, /03L-0:on 800618,during Mode 2 Operation,Greater than Twelve Step Disagreement Was Noted Between Individual & Group Position Indication for Rod G-9.Caused by Voltage Drift in Signal Conditioning Card
References
LER-80-057-03L, LER-80-57-3L, NUDOCS 8007150701
Download: ML19320C053 (2)

LER-1980-057, /03L-0:on 800618,during Mode 2 Operation,Greater than Twelve Step Disagreement Was Noted Between Individual & Group Position Indication for Rod G-9.Caused by Voltage Drift in Signal Conditioning Card

Event date:
Report date:
3381980057R03 - NRC Website

text

nJ-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/1/ (2)

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

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

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LICENSEE CODE LICENSE NUMBER LICENSE TYPE CAT

/L/ (6)

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

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During normal Mode 2 operation, a greater than 12 step disagreement was noted /

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between individual ~and group position indication for rod G-9.

This is contrary /

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to the limit specified in T.S. 3.1.3.2.

The rod position indication was

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returned to servire within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />, therefore the health and safety of the

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/ -public were not affected. This item is 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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/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 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) /X/ (19) /Z/ (20) /2/ (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 indicator disagreement was due to a voltage drift in the

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signal conditioning card. The card was recalibrated and tested satisfactorily./

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The indication was restored to full operability within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.

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FACILITY-METHOD OF STATUS

% POWER OTHER STATUS

/ ( 0) DISCOVERY DISCOVERY DESCRIPTION (32)

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/D/-(28)

/0/0/0/ (29) /

NA

/A/ (31)

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OPERATOR OBSERVATION

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

LOCATION Or RELEASE (36)

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NA

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PERSONNEL EXPOSURES NUMBER TYPE DESCRIPTION (39)

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NA

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PERSONNEL INJURIES NUMBER DESCRIPTION (41)

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LOSS OF OR DAMAGE TO FACILITY ( )

TYPE

DESCRIPTION

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NA

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PUBLICITY

. ISSUED DESCRIPTION-(45)

NRC USE ONLY

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

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o-Virginia' Electric and Power Company North Anna Power Station, Unit #1 Attachment: Page ' of 1 Docket No. 50-338 I

- Report No. LER 80-057/03L-0

Description of Event

On June 18, 1980 during normal mode 2 operation, a greater than 12 step disagreement was noted between the rod position indication G-9 and the group demand indication. 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 insertion limits and alignment. Since the control rod was not actually misaligned and the position indication restored within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />, there was no effect on the safe operation of the unit. Therefore, the health and safety of the public were not affected.

Cause of Event

The cause of this event was a voltage drift in the signal conditioning card.

It has been determined that voltage is affected by the temperature of the' rod drive line, the frequency of the excitation source and'by secondary loadings.

Immediate Corrective Action

A recalibration and functional test was performed and the IRPI returned to service.

Scheduled Corrective Action j

A long term investigation'into the problems ar.sociated with the t

position indicating system is continuing. No future corrective action will be scheduled until an adequate design modification is developed.

1 Actions Taken to Prevent Recurrence No actions taken at this time.

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