05000368/LER-1980-060-03, Core Protection Calculator D Failed & on 801120 Calculator C Failed.Cause Undertermined.Watchdog Timer Timed Out Preventing Communications.Sys Reinitialized & Bypasses Removed

Core Protection Calculator D Failed & on 801120 Calculator C Failed.Cause Undertermined.Watchdog Timer Timed Out Preventing Communications.Sys Reinitialized & Bypasses Removed

ML19345D426
Person / Time
Site:	Arkansas Nuclear
Issue date:	12/09/1980
From:	Shively C ARKANSAS POWER & LIGHT CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML19345D425	List:
References
LER-80-060-03X, LER-80-60-3X, NUDOCS 8012150090
Download: ML19345D426 (1)

LER-1980-060, Core Protection Calculator D Failed & on 801120 Calculator C Failed.Cause Undertermined.Watchdog Timer Timed Out Preventing Communications.Sys Reinitialized & Bypasses Removed

Event date:
Report date:
3681980060R03 - NRC Website

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UPDATE REPORT - PREVIOUS REPORTS DATED 2/5/80 AND 8/28/80 F

NRC FORM 366 U.S. NUCLE AR REGUtATORY COMMISSION (7 77)

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80 EVENT DEscalPTION AND PAQtl ABLE CONSEQUENCES soi2i i During Mode 1 operation, the "

Core Protection Calculator (CPC) failed i ioi3i t on 7/30/80 and the "C" CPC failed on ' 11/20/80.

The ONBR/LPD trips were i I by-passed on the affected CPC channel, placing the reactor trip logic in 1 o.

In is t I a two out of three trio secuence.

The unaffected channels remained oper-1 i able.

Similar LER's for CPC "C" are: 50-368/80-002,79-098, 79-096; for i o6 mT) I the "D" CPC is 50-368/80-008; for the "A" CPC are 50-368/80-051,79-045. I i o p. i i Reporatable per T.S. 6.9.1.9.b.

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CAUSE DESCR.PTION AP.3 CORREC(IVE ACTIONS h liio n I Investiaation did not reveal the root cause of the CPC program halt. Thei ii ii i

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The CPC system was re-initialized, by-i g i passes removed, and the unit returned to operable status.

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Chris N. Shively 501/968-2519 NAME oF PPEPAREP 8012150090