ML19345H389

LER 81-037/03L-0:on 810502,rod Position Indicator for Rod D-6 Drifted from Group Demand Position.Caused by Instrument Drift.Rod Recalibr & Instrument Returned to Svc

ML19345H389
Person / Time
Site:	North Anna
Issue date:	05/15/1981
From:	VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19345H388	List: ML19345H387 ML19345H389
References
LER-81-037-03L, LER-81-37-3L, NUDOCS 8105200231
Download: ML19345H389 (2)

Text

. . - - .

U.S. NUCLEAR REGULATORY C0!9 FISSION CONTROL BLOCK / / / / / / / (1) (PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION)

. /0/1/ /V/A/N/A/S/2/ (2) /0/0/-/0/0/0/0/y-/0/0/ (3) /4/1/1/1/1/ (4) / / / (5)

LICENSEE CODE LICENSE NUMBER LICENSE TYPE CAT

/0/1/

E g/ (6) /0/5/0/0/0/3/3/9/ (7) /0/5/0/2/8/1/ (8) /o /s /1/5 /8 /1/ (9)

DOCKET NLMBER EVENT DATE REPORT DATE EVENT DESCRIPTION AND PROBABLE CONSEQUENCES (10) 4

/0/2/ / On May 2, 1981, with Unit 2 at 100% power, the rod position indicator for rod /

/0/3/ / D-6 drifted > 12 steps from grcup demand position. Since the control rod /

/0/4/ / indication was restored to service within eight hcurs, the public health and /

/0/5/ / safety were not affected. /

/0/6/ / /

/0/7/ / /

/0/8/ / /

SYSTEM CAUSE CAUSE C0dP. VALVE CODE CODE SUBCODE COMPONENT CODE SUBCODE SUBCODE

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

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

(17) REPORT NUMBER /8/1/ /-/ /0/3/7/ /\/ gg/ /L/ L-/ ' LO/

ACTION FUTURE EFFECT SHUTDOWN ATTACHhr.NT NPRD-4 PRIlfE COMP. COMPONENT TAKEN ACTION ON PLANT METHOD HOURS SUBMITTED FORM SUB. SUPPLIER MANUFACTURER

/E/ (18) LZ/ (19) g/ (20) LZ/ (21) /0/0/0/0/ (22) LY/ (23) g/ (24) g/ (25) /W/1/2/0/ (26)

CAUSE DESCRIPTION AND CORRECTIVE ACTIONS (27) l /1/0/ / The cause of this discrepancy was instrument drift. A recalibration of rod /

/1/1/ / D-6 was performed and the indicator was returned to service. /

/1/2/ / /

l /1/3/ / /

/1/4/ / /

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

/1/5/ [E/ (28) /1/0/0/ (29) / NA / ( 0) DISCOVERY g/ (31) / OPERATOR OBSERVATION /

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

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

PERSONNEL EXPOSURES NUMBER TYPE DESCRIPTION (39)

/1/7/ /0/0/0/ (37) /Z[ (38) L NA /

PERSONNEL INJURIES NUMBER DESCRIPTION (41)

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

LOSS TYPE OF OR DAMAGE TO FACILITY (' }

DESCRIPTION

/Z[(42) /

/1/9/ NA /

PUBLICITY ISSUED DESCRIPTION (45) NRC USE ONLY

/2/0/ /N/ (44) / NA ////////////j l 8105200 @

w.-,

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

Attachment:

Page 1 of 1 Docket No. 50-339 Report No. LER El-037/03L-0 Description of Event On May 2,1981, while operating in Mode 1 at 100% power the control room operator observed that the Rod Position Indication for rod D-6 was greater than 12 steps from the control rod demand position. This event is contrary to T.S. 3.1.3.2 and reportable pursuant to T S.

6.9.1.9.b.

Probable Consequences of Occurrence Since the control rod position indicator was restored to service within eight hours, the health and safety of the public was not affected.

Cause of Event The cause of disagreement between the individual rod position indication was due to instrument drift.

'.mmediate Corrective Action The immediate corrective action was to perform a recalibration for rod D-6 and return it to service.

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 action to prevent recurrence is required.

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

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