ML19276H022

LER 79-018/03L-0 on 790706:during Routine Testing,Reactor Vessel Level Indicating Switch NBI-LIS-58A Was Found W/Trip Point Less than Allowed.Caused by Sediments of Dust & Moisture in Auxiliary Switch

ML19276H022
Person / Time
Site:	Cooper
Issue date:	08/03/1979
From:	Phillips D NEBRASKA PUBLIC POWER DISTRICT
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML19276H021	List: ML19276H020 ML19276H022
References
LER-79-018-03L, LER-79-18-3L, NUDOCS 7908310364
Download: ML19276H022 (1)

Text

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EVENT OATE 74 75 R E *C5t T D A T E 7 8 60 61 DOCK ET NUVSEq EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h I'5'TTI I During routine '..esting, reactor vessel level indicating switch N11-LIS-58A switch an,- I f oTTI l er b one was found with 4 trip point less conservative than allc,ved in Tech. Spec. Tabid o 4 1 3 2.A. There was no significant occurrence as a result of this event. The redunAnt 1 o s l level switch NBI-LIS " A was operable. There were no adverse affects to public health l I o Is I land safety. This event is cepetitive. Reference LER 79-5, 77-12 1 o 7 I o a l I N'E C0oE ssCO$E CouPONENT Coof susCIot sus $of R lC lD l@ {@ {Z l@ llN S lT R lU l@ y@ W @ 20 7 8 9 10 11 12 13 18 19

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CAUSE OESCRIPTION AND COPRECTIVE ACTICNS h f7TTl 'A Yarway Model 4418C level indicating switch failed to actuate within tolerance. In- l t i [vestigation disclosed that sediment consisting of dust and moisture in the auxiliary I g switch mechanism had caused the switch to hang-up. The switch was cleaned and after i g ] cleaning tested satisfactorily. A new mechanical cam actaated solid state switch y l module is under evaluation. I F 8 9 80 ST s  % POWER OTHER STATUS I O RY DsSCOVERY oE5CF11PTION i s y @ l0l9l5l@l NA l l B l@l Routine Surveillance Testing l AC flVITY CO TENT RELEASED OPRELEASE AMOUNT OP ACTivlTY LOCATION OP RELEASE G (Z 7 89_

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