05000318/LER-1978-046-03, /03L-0 on 781217:during Surveillance,Noted That Control Element Assembly 18 Would Not Electrically Drive Down in Manual Individual or Manual Group.Caused by Inoperable Timer for Assembly

/03L-0 on 781217:during Surveillance,Noted That Control Element Assembly 18 Would Not Electrically Drive Down in Manual Individual or Manual Group.Caused by Inoperable Timer for Assembly

ML19259B349
Person / Time
Site:	Calvert Cliffs
Issue date:	01/16/1979
From:	Davis S, Romney K BALTIMORE GAS & ELECTRIC CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19259B347	List: 05000318/LER-1978-046, Forwards LER 78-046/03L-0 05000318/LER-1978-046-03, /03L-0 on 781217:during Surveillance,Noted That Control Element Assembly 18 Would Not Electrically Drive Down in Manual Individual or Manual Group.Caused by Inoperable Timer for Assembly
References
LER-78-046-03L, LER-78-46-3L, NUDOCS 7901260198
Download: ML19259B349 (2)

LER-1978-046, /03L-0 on 781217:during Surveillance,Noted That Control Element Assembly 18 Would Not Electrically Drive Down in Manual Individual or Manual Group.Caused by Inoperable Timer for Assembly

Event date:
Report date:
3181978046R03 - NRC Website

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NRC FORM 366 U. S. NUCLEAR REGULATOF.Y COMMISSION 17 773 LICENSEE EVENT REPORT CONTROL BLOCK: l l

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7 8 9 UCENSEE CODE 14 15 LICENSE NUMBER 25 26 UCENSE TYPE JO 57 CAT $8 CON T aE' aj Ll@l0l5l0l0l0l3l118]@]ll2 117l7l8l@l0Il111617 9l@

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8 60 61 DOCKET NUMBER 68 69 EVENT DATE 74 75 REPORT DATE

- 80 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h o 2 l At 0705 while performing routine surveillance testino, it was discovered that I

I control Element hsembly 18 (CEA-18) would not drive down electrically in o

2 l manual individual or manual group. CFA-18 was full out and level with its I

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o s I group. CEA-18 was declared inoperable per T.S. 3.1.3.1.

Ac 0750 the shutdown I

l margin was verified greater than 3.4%, CEA-18 inoperable. All other CEAs I

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l remained operable and CEA-18 remained tricable during the event. CEA-18 was I

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i returned to service at 0950. This is not a repetitive occurrence.

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33 34 35 38 37 40 41 42 43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h o l lThe timer for CEA-18 was testeo and found to be inocerable. The timer modtile I

i m Iwas replaced and the rod ;avement tested. The available data for timer coera-I l ting hours and failures indicate that the timers have a mean time between I

2 failure (MTBF) of 1.65 x 106 hrs. The timers have a larce MTBF, are in a I

g g imonthly surveillance test orogram, and timer failure does not affect trinability I

STA 4 POWER OTHER STATUS 3C RY DISCOVERY DESCRIPTION

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1 12 11 44 45 46 90 [i QJ l Z l @D OF RELEASE @@l l

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DOCKET NO. 50-318 EVENT DATE 12/17/78 REPORT DATE 1/16/79 LER 78-46 ATTACHMENT CAUSE DESCRIPTION AND CORRECTIVE ACTIONS:

(CONTINUED) of the plant. Due to the above factors, no further action is necessary.