05000338/LER-1981-049-03, /03L-0:on 810704,control Rod Position Indication for Control Bank B,Rod D 10,was Pegged & Computer Indication Deviated from Group Demand Position.Caused by Instrument Drift Generic to Westinghouse Sys

/03L-0:on 810704,control Rod Position Indication for Control Bank B,Rod D 10,was Pegged & Computer Indication Deviated from Group Demand Position.Caused by Instrument Drift Generic to Westinghouse Sys

ML20009G654
Person / Time
Site:	North Anna
Issue date:	07/24/1981
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20009G640	List: 05000338/LER-1981-049, Forwards LER 81-049/03L-0 05000338/LER-1981-049-03, /03L-0:on 810704,control Rod Position Indication for Control Bank B,Rod D 10,was Pegged & Computer Indication Deviated from Group Demand Position.Caused by Instrument Drift Generic to Westinghouse Sys
References
LER-81-049-03L-01, LER-81-49-3L-1, NUDOCS 8108040517
Download: ML20009G654 (2)

LER-1981-049, /03L-0:on 810704,control Rod Position Indication for Control Bank B,Rod D 10,was Pegged & Computer Indication Deviated from Group Demand Position.Caused by Instrument Drift Generic to Westinghouse Sys

Event date:
Report date:
3381981049R03 - NRC Website

text

--

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

(PLEASE PRINT 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/

/L/ (6)

/0/5/0/0/0/3/3/8/

(7)

/0/7/0/4/8/1/

(8)

/ c/ 7/ 2/ 4/ 8/1/ (9)

DOCKET DUMBER EVENT DATE REPORT l> ATE EVENT DESCRIPTION AND PROBABLE CONSEQUENCES (10)

/0/2/

/ On July 4, 1981, with Unit 1 at 100 percent power the Control Room Operator

/

/0/3/

/ observed control rod position indication for control Dank B rod DIO was pegged

/

/0/4/

/ and computer indication deviated from group demand position indication by greaterf

/0/5/

/ than 12 steps.

This event is reportable pursuant to T.S. 6.9.1.9.b.

The i.ction /

/0/6/

/ Statement of the LCO (T.S. 3.1.3.2) was met.

The public health and safety were /

/0/7/,

/ not affected.

/

/0/8/

/_

/

SYSTEM CAbSE

CAUSE

COMP.

VALVE CODE CODE SUBCODE COMPONENT CODE SUBCODE SUBCODE

/0/9/

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

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

CODE TYPE NO.

(17) REPORT NUMBER

/8/1/

/-/ /0/4/9/

/\\/

/0/3/

/L/

/-/

/_0/

ACTION FUTURE EFFECT SHUTDOWN ATTACHMENT NPRD-4 PRIME COMP.

COMPONEN'1 TAKEN ACTION ON PLANT METHOD HOURS SUBMITTED FORM SUB. SUPPLIER MANUFACTUREI ME/ (18)

[Z/ (19) g/ (20) g/ (21) /0/0/0/0/ (22) g/ (23) /N/ (24) g/ (25) /W/1/2/0/ (2(

Z CAUSE DESCRIPTION AND CORRECTIVE ACTIONS (27)

/1/0/

/ Instrument drift which is generic to the Westinghouse analog rod position indica-/

/1/1/

/ tion systems caused the indicator disagreement. Rod position indicating channel /

/1/2/

/ DIO was recalibrated and returned to service.

/

/1/3/

/

/

/1/4/

/

/

FACILITY METHOD OF STATUS

% POWER OTHER STATUS

/ (30) DISCO M Y DISCO M Y DES N ION (32)

/1/5/

g/ (28)

/1/0/0/ (29)

/

NA

/B/ (31)

/

Operator Observation

/

ACTIVITY CONTENT RELEASED OF RELEASE AMOUNT OF ACTIVITY (35)

LOCATION OF RELEASE (36)

/1/6/

LZ/ (33)

M/ (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

/

LOST. OF OR DAMAGE TO FACILITY (43)

TYPE

DESCRIPTION

/1/9/

/Z/ (42)

/

NA

/

PUBLICITY 8108040517 810724 DR ADOCK 05000 ISSUED DESCRIPTION (45) g NRC USE ONLY

/2/0/

/N/ (44) /

NA

/////////////

NAME OF PREPARER W. R. CARIVRIGHT PHONE (703) 894-5151

Virginia Electric and Power Company North Anna Power Station, Unit #1 Atsachment:

Page 1 of 1 Docket No. 50-338 Report No. LER 81-049/03L-0

Description of Event

On July 4,1981, with Unit 1 at 100 percent power, the Control Room Operator observed control rod position indication for Control Bank 3 rod D 10 was pegged and computer indication deviated from group demand position indication by greater than 12 steps.

This event is reportable pursuant to T.S. 6.9.1.9.b.

Probable Consequences of Occurrence The action statement of the LCO (T.S. 3.1.3.2) was met.

The public health and safety were not affected.

Cause of Event

Instrument drift which is generic to the Westingbouse analog rod position indication systems caused the indicator disagreement.

Immediate Corrective Action

Rod position indication channel DIO was recalibrated.

Scheduled Corrective Action A long term investigation into the problems associated with the position indicating system is continuing. 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 Westinghouse rod position system used at North Anna Power Station Units 1 and 2.