ML19351F555

LER 80-098/03L-0:on 801208,individual Rod Position Indication for Rod J-9 in Shutdown Bank B Deviated from Demand Position by More than 12 Steps.Caused by Instrument Drift.Rod Position Indicator Channel Recalibr

ML19351F555
Person / Time
Site:	North Anna
Issue date:	01/06/1981
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19351F546	List: ML19351F545 ML19351F555
References
LER-80-098-03L-01, LER-80-98-3L-1, NUDOCS 8101130480
Download: ML19351F555 (2)

Text

U.S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT C0hTROL BLOCK / / / / / / / (1) (PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION)

/0/7/ /V/A/N/A/S/2/ (2) /0/0/-/0/0/0/0/0/-/0/0/ (3) /4/1/1/1/1 (4) W (5)

LICENSEE CODE LICENSE NUMBER LIG NSE TYPE CAT

/0/1,/ POR E /L/ (6) /0/5/0/0/0/3/3/9/ (7) /1/2/0/8/8/0/ (8) / d 1/ d d & L' (9)

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

/0/2/ / On December 8, 1980, with the unit in mode 3, the individual rod position /

/0/3/ / indication for rod J-9 in shutdown bank "B" deviated from the group demand /

/0/4/ / position by greater than 12 steps. The reactor trip breakers were immediately /

/0/5/ / opened in compliance with T.S. 3.1.3.3, and the IRPI was recalibrated. There- /

/0/6/ / fore, the health and safety of the general public were not affected. This /

/0/7/ / event is reportable pursuant to T.S. 6.9.1.9.b. /

/0/8/ / /

SYSTEM CAUSE CAUSE COMP. VALVE CODE CODE SUBCODE COMPONENT CODE SUBCODE SUBCODE

/0/9/ /I/E/ (11) /E/ (12) /E/ (13) /I/N/S/T/R/U/ (14) g/ (15) LZ/ (16)

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

(17) REPORT NUMBER /8/0/ /-/ /0/9/8/ /\/ /0/3/ /L/ /-/ LO/

ACTION FITTURE EFFECT SHUTDOWN ATTACHMENT NPRD-4 PRIME COMP. COMPONENT TAKEN ACTION ON PLANT METHOD HOURS SUBMITTED FORM SUB. SUPPLIER MANUFACTLTER

/E/ f.18) /Z/ (19) /Z/ (20) /Z/ (21) /0/0/0/0/ (22) g/ (23) /N/ (24) [NL (25) /W/1/2/0/(26)

CAUSE DESCRIPTION AND CORRECTIVE ACTIONS (27)

/1/0/ / The cause of this indicator disagreement was attributed to instrument drift. /

/1/1/ / This is a recurring problem and is generic to Westinghouse Analog position /

/1/2/ / indication systems. The rod position indicator channel for rod J-9 gas /

/1/3/ / properly recalibrated and returned to service. /

/1/4/ / /

FACILITY METHOD OF STATUS  % POWER OTHER STATUS DISCOVERY DISCOVERY DESCRIPTION (32)

/1/5/ [B{ (28) /0/0/0/ (29) / NA / (30) /A/ (31) / Operator Observation /

ACTIVITY CONTENT RELEASED OF RELEASE AMOUNT OF ACTIVITY (35) LOCATION OF RELEASE (36)

/1/6/ /Z/ (33) ZZL (34) / NA / / NA _/

PERSONNEL EXPOSURES NUMBER TYPE DESCRIPTION (39)

/1/7/ /0/0/0/ (37) [ZL (38) / NA /

PERSONNEL INJURIES NUMBER DESCRIPTION (41)

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

LOSS OF OR TYPE DAMAGE TO FACILITY (43)

DESCRIPTION

/1/9/ /Z/ (42) / NA /

PUBLICITY ISSUED DESCRIPTION (45) NRC USE ONLY ,

/2/0[ /N/ (44) / NA /////////////

NAME OF PREPARER W. R. CARTVRIGHT PHONE (703) 894-5151 8101130%2O

Virginia Electric and Power Company North Anna Power Station, Unit 2

Attachment:

Page 1 of I Docker No. 50-339 Report No. LER 80-098/03L-0 Description of Event On December 8, 1980, with the unit in Mode 3, the Control Room Operator observed a greater than 12 step disagreement between the Individual Rod Position Indicator (IRPI) for rod J-9 in Shutdown Bank "B" and the group demand indication.

Probable Consequences of Occurrence Operability of control rod position indication is required to determine rod position and thereby ensure compliance with the control rod alignment and insertion limits. Since the control rod was not misaligned and the position indication was properly restored, there was no effect on the safe operation of the plant. As a result, the health and safety of the general public were not affected.

Cause of Event The cause of the disagreement in rod position indication was instru-ment drift. This drift 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 reactor was immediately tripped as per T.S. 3.1.3.3 and the rod position indicator channel for ro,d J-9 was satisfactorily recalibrated and returned to service.

i 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 proven effective.

Actions Taken to Prevert Reccurrence .

No further action are required at this time.

Generic Implications

')

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

l t

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