05000368/LER-1980-060-03, Core Protection Calculator Channel Failed,Causing Trip Sequence.Cause Under Investigation.Watch Dog Timer Timed Out,Rendering Channel Inoperable.Sys Reinitialized & Bypasses Removed

Core Protection Calculator Channel Failed,Causing Trip Sequence.Cause Under Investigation.Watch Dog Timer Timed Out,Rendering Channel Inoperable.Sys Reinitialized & Bypasses Removed

ML19340F114
Person / Time
Site:	Arkansas Nuclear
Issue date:	01/13/1981
From:	Shively C ARKANSAS POWER & LIGHT CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML19340F113	List:
References
LER-80-060-03X, LER-80-60-3X, NUDOCS 8101190451
Download: ML19340F114 (2)

LER-1980-060, Core Protection Calculator Channel Failed,Causing Trip Sequence.Cause Under Investigation.Watch Dog Timer Timed Out,Rendering Channel Inoperable.Sys Reinitialized & Bypasses Removed

Event date:
Report date:
3681980060R03 - NRC Website

text

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..o, o.ii EVENT OESCR.PTION AND PRCS ABLE CONSE0VENCES h i Durino Mode 1 operation, as indicated on the attached 100. the Core' I

to62i i Protection Calculator (CPCI channels failed. causing a channel DNBR/l_PL J oi Uud) I trip. The trip signals were bypassed on the affected CPC channel, placing lo isi i the Reactor triD looic in a two out of three trio secuence.

The unaffectt i e is i 1 ed channels remained operable. Similar occurrences are.. indicated on the i loi>llattached loc.

Pecortable Der T.S. 6.9.1.9.b.

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i m I" Watch doo" timer timed out preventing console cormiunications, rendering i m ithe CPC channel technically inocerable. The CPC system was reinitialized;i 1 bypasses removed, and the unit returned to operable status. A failure i

i,13i iii. i iinvestigation is in progress.

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s LER 50-368/80-060 Rev. 3 CORE PROTECTION CALCULATOR FAIL LOG

("WATCHD0G" TIMER TIMED OUT)

DATE CHANNEL Rx PWR.

LER 6/13/79 A

10-4%

368/79-045 12/11/79 C

50%

368/79-096 12/05/79 C

30%

368/79-098 1/10/80 C

50%

368/80-002 1/17/80 B

50%

368/80-004 1/23/80 B

100%

368/80-006 1/28/80 B

100%

368/80-008 7/17/80 A

100%

368/80-051 7/30/80 D

100%

368/80-060 11/20/80 C

65%

368/80-060 Rev. I 12/02/80 D

40%

368/80-060 Rev. 2 12/19/80 C

87%

368/80-060 Rev. 3 12/21/80 C

1%

368/80-060 Rev. 3