05000311/LER-1982-141, Updated LER 82-141/03X-1:on 821121 & 1204,P-250 Computer Inoperable Due to Parity Error.Caused by Periodic Increases in Ambient Temp Due to Insufficient Ventilation.Computer Reprogrammed & Action Statement Terminated

Updated LER 82-141/03X-1:on 821121 & 1204,P-250 Computer Inoperable Due to Parity Error.Caused by Periodic Increases in Ambient Temp Due to Insufficient Ventilation.Computer Reprogrammed & Action Statement Terminated

ML20083F073
Person / Time
Site:	Salem
Issue date:	12/16/1983
From:	Rupp J, Zupko J Public Service Enterprise Group
To:	Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
LER-82-141-03X, LER-82-141-3X, NUDOCS 8312300129
Download: ML20083F073 (4)

LER-2082-141, Updated LER 82-141/03X-1:on 821121 & 1204,P-250 Computer Inoperable Due to Parity Error.Caused by Periodic Increases in Ambient Temp Due to Insufficient Ventilation.Computer Reprogrammed & Action Statement Terminated

Event date:
Report date:
3112082141R00 - NRC Website

text

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EVENT DATE 74 76 REPORT DAT E S0 00 61 DOCKET NUMSER EVENT DESCRIPTION AND PROBABLE CONSEQUENCES O'a

' g l On two separate occasions, on November 21 and December 4,1982, during routine operation,

, ,,i g,i j the control room opdrator discovered that the P-250 Computer was inoperable due to a g

, , l parity error. Since it utilizes the computer for inputs and calculations, the Reactorg O 6 l Coolant System (RCS) subcooling monitor was declared inoperable and Action Statement 0 6 1 3.3.3.7a was entered. Wide range RCS temperature and pressure indications and steam

o 7 l tables were available throughout the occurrence. The event constituted operat. ion in ag a g degraded modo in accordance with Technical Specification 6.9.1.9b. g 7 se so SYSTEM CAUSE CAUSE COMP. VAtyE I CODE CODE SUSCODE COMPONENT CODE SUBCODE SUSCOCE 7

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, j reprogrammed and the action statement terminated. The power supply: breaker was replac9d i 3 l and the air conditioning units were repaired. DCRs are being formulated tu install l 4 l Safety Parameter' Display Systems. l

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.Public Service Electric and Gas Company P.O. Box E' Hancocks Bridge, New Jersey 08038 Salem Generating Station December 16, 1983 Dr.-Thomas E. Murley

. Regional Admiriistrator USNRC Region l' 631. Park Avenue King _of-Prussia, Pennsylvania 19406

Dear Dr. Murley:

G LICENSE NO. DPR-75 DOCKET NO. 50-311 ,

REPORTABLE OCCURRENCE 82-141/03X-1 SUPPLEMENTAL REPORT.

Pursuant to the-requirements of Salem Generating Station Unit No.'2 Technical Specifications, Section 6.9.1.9b, we are submitting supplemental Licensee Event Report for Reportable Occurrence 82-141/03X-1.

Sincerely yours, v ,

J. M.-Zupko, Jr.

General Manager --

Salem Operations JR:kil df CC: Distribution Ifl The Energy People [

% 21tG 120M) 1181 1:

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Raport1 Number:: , 141/03X-1 '

Report Date:~ 12-16-83

~

Occurrenc_e. Dates: l11-21-82 J

12-04-82

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' Facility: Salem Generating = Station Unit 2

-Public-Service = Electric & Gas' Company Hancock's Bridge,-New Jersey- 08038

-IDENTIFICATION OF 0CCURRENCE:

Accident Monitoring Instrumentation . Reactor Coolant System Subcooling Margin Monitor - Inoperable.

This report-was: initiated-by Incident Reports82-482 and 82-486.

,EONDITIONS PRIOR TO OCCURRENCE:

~ Mode 1 - RX Power .81 5 - Unit Load 890 MWe.

DESCRIPTION OF OCCURRENCE:

! On two separate occasions, ~ at- 1420' hours, November. 21, 1982, and at 0730 hours0.00845 days <br />0.203 hours <br />0.00121 weeks <br />2.77765e-4 months <br />,. December 4, 1982, during routine operation, the Control Room Operator' discovered that the-P-250 Computer was inoperable due to e parity-error; attempts to bootstrap the computer failed. Since it utilizes the_ computer for inputs and calculations, the Reactor Coolant i System.(RCS) subcooling margin monitor in both cases was declared

-inoperable,-and Technical Specification Action Statement 3.3.3.7a was entered. :Thefwide range RCS temperature and pressure _ indications were operable 1and: steam tables were available in the Control Room throughout:both occurrences.

APPARENT CAUSE OF OCCURRENCE: .

The_ malfunctions of the P-250 Computer were apparently due to the power-supply-breaker tripping in association with periodic increases in cabinet ambient temperatures (approximately 80 F). The temperature

' increases were attributed to inadequate capacity of the cabinet cooling system.- Previous malfunctions of the P-250 computer were documented in LER'82-131/03L.

ANALYSIS OF OCCURRENCE:

~0perability of the accident monitoring instrumentation ensures that sufficient information is available on selected plant parameters to monitor and assess these variables following an accident.

-Action Statement 3.3.3.7a requires:

With the number of operable accident monitoring channels less than the required r. umber of channels, restore the inoperable channel (s) to operable statue within 7 days, or be in at least hot shutdown within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

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LER '82-141/ 03X-1

[2-ANALYSIS OF-OCCURRENCE: (cont'd)-

.As noted, wide range indication and steam. tables were~available,

- allowing determination'ofcthe subcooling margin.- ~ The RCS.subcooling margin, monitor was returned.to" operation within the time specified by the action requirement.- The events therefore involved no undue risk to

- 'the health and safety of the. 7 pub.lic. Due to the loss of redundancy,

-the occurrences constituted operation in a degraded mode' permitted by-La: limiting' condition for-operation and were' reported in accordance with Technical: Specification 6.9.1.9b on December 8, 1982.

-CORRECTIVE' ACTION:

1 In'each case,.following investigation of.the: problem, the tripped breaker was reset and the bootstrap' program was successfully loaded.

,In the-first instance, the P-250 Computer:was returned to service and-the RCS subcooling margin monitor was satisfactorily tested. Action

^ Statement-3.3.3.7a was terminated.at 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br />, November 21, 1982.

4

'Following the.second occurrence, a temporary. fan was installed in the cabinet to-increase air circulation and improve cooling. The computer

. was returned to operation and the monitor was satisfactorily tested.

Action Statement 3.3.3.7a was terminated at 1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br />, December 4, 1982.

Subsequently, the power supply breaker was replaced-and the air conditioning units were repaired. Since then, Unit 2 P-250 computer has performed satisfactorily. Due to occurrences involving Unit 1 P-250 Computer (documented in LER's 83-039/03L, 83-043/03L and

.83-045/03L), the following actions have been taken:

1. An information directive was issued to operations personnel to ensure proper response to P-250 Computer malfunctions.

2. Due to the recurrenceuof ventilation problems, an Engineering Department investigation-will be performed for possible 3

improvements to the-system.

i

3. DCR's 1EC-1365 ano 2EC-1366 are being formulated for the

' design of Safety ~ Parameter Display Systems (SPDS). '

1, Installation is expected to be started late in 1984.

f Associated with installation of-these systems, the RCS subcooling monitors would be disconnected from the process computers.and connected to the safety.related SPDS computers.

-(The P-250' Computers are not safety related equipment)

FAILURE DATA:

k Westinghouse Electric Corp.

PRODAC-250 Computer ,,

Prepared By J. Ruon v

/ 'Gdfieral Wanager -

) Salem Operations

'SORC Me'eting No.83-152

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