05000339/LER-1981-004-03, /03L-0:on 810104,during Mode 1 Operation,Flux Penalty Summing Amplifier Found Failed During Loop Calibr Check.Caused by Faulty NSA Card.Card Replaced & Calibr

/03L-0:on 810104,during Mode 1 Operation,Flux Penalty Summing Amplifier Found Failed During Loop Calibr Check.Caused by Faulty NSA Card.Card Replaced & Calibr

ML20009C182
Person / Time
Site:	North Anna
Issue date:	01/21/1981
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20009C180	List: 05000339/LER-1981-004, Forwards LER 81-004/03L-0 05000339/LER-1981-004-03, /03L-0:on 810104,during Mode 1 Operation,Flux Penalty Summing Amplifier Found Failed During Loop Calibr Check.Caused by Faulty NSA Card.Card Replaced & Calibr
References
LER-81-004-03L, LER-81-4-3L, NUDOCS 8107200351
Download: ML20009C182 (2)

LER-1981-004, /03L-0:on 810104,during Mode 1 Operation,Flux Penalty Summing Amplifier Found Failed During Loop Calibr Check.Caused by Faulty NSA Card.Card Replaced & Calibr

Event date:
Report date:
3391981004R03 - NRC Website

text

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

(PLEASE PRINT OR TYPE ALL REQUIREL INFORMATION)

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

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LICENSEE CODE LICENSE NUMBER LICENSE TYPE CAT

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/L/ (6)

/0/5/0/0/0/3/3/9/ (7)

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

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On January 1, 1981, during Mode 1 operation, the flux penalty summing amplifier /

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(NM-432A) was found to be failed during a loop calibration check. The failed /

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channel was in the trip position and the remaining channel was functioning pro-/

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perly. Therefore the health and safety of the public were not affected. This /

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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/A/ (11) /E/ (12)

/G/ (13) /I/N/S/T/R/U/ (14) g/ (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 AlfACHMENT NPRD-4 PRIME COMP. COMPONENT TAKEN ACTION ON PLANT METHOD HOURS SUBMITTED FORM SUB. SUPPLIER MANUFACTURER

/A/ (18) /Z/ (19) /Z/ (20) /Z/ (21) /0/0/0/0/ (22) g/ (23) [Nf/,(24) /N/ (25) /W/1/2/0/(26)

CAUSE DESCRIPTION AND CORRECTIVE ACTIONS (27)

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/ This failure was caused by a faulty NSA card (C3-141). The card was replaced

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/ and calibrated. The loep calibration check was performed and the channel re-

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FACILITY METHOD OF STATUS

% POWER OTHER STATUS DISCOVERY DISCOVERY DESCRIPTION (32)

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NA

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Periodic Test

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ACTIVITY CONTENT RELEASED OF RELEASE AMOUNT OF ACTIVITY (35)

LOCATION OF RELEASE (36)

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NA

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NA

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PERSONNEL EXPOSURES NUMBER TYPE DESCRIPTION (39)

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

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NA

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PERSONNEL INJLTIES NUMBER DESCRIPTION (41)

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LOSS OF OR DAMAGE TO FACILITY (43)

TYPE

DESCRIPTION

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PUBLICITY ISSUED DESCRIPTION (45)

NRC USE ONLY

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/N/ (4'4) /

NA

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NAME OF PREPARER W. R. CARTWRIGRT PHONE (703) 894-5151 8107200351 810121 PDR ADOCK 05000339 S

PDR

Virginia Electric and Power Company North Anna Power Station, Unit 2 Attachment: Page 1 of 1 Docker No. 50-339 Report No. LER 81-004/03L-0

Description of Event

On January 4,1981, the flux penalty summing amplifier was found to be failed during a loop calibration check.

Probable Consequences of Occurrence The overtemperature AT trip function is to provide core DNB protec-tion under adverse conditions of RCS pressure, power, average coolant temperature and axial power distribution. Should temperatute, pressure or flux level approach limiting conditions for a given core thermal power condition, the AT protection system will automatically take stepa necessary to reduce power or trip the reactor depending on the degree of departure from safe limits. The failure of this amplifier (NM-432A) did, in effect, remove the automatic penalty from the over-temperature AT trip setpoint due to an abnormal axial power distribution.

The failed channel was in the trip mode and the remaining channels functioned properly. Therefore, the health and safety of the public were not affected.

Cause of Event

i This event was caused by a failed NSA card (C3-141). The failure in this card was due to a shorted capacitor. The capacitor was replaced and the card tested.

t

Immediate Corrective Action

the failed card was replaced, the channel calibrated and returned to service.

Scheduled Corrective Action No further action required.

Actions Taken to Prevent Reccurrence No further action required.

Generic Implications There are no generic implications from this event.

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