ML19253B057

LER 79-030/03L-0:on 790805,control Element Assemblies 6,7, 49,51 & 53 Failed to Initiate Motion Inhibit Function. Caused by Drifting of Motion Inhibit Setpoint Voltage Levels.Setpoints Will Be Reduced

ML19253B057
Person / Time
Site:	Calvert Cliffs
Issue date:	08/31/1979
From:	Heibel R, Rizzo P BALTIMORE GAS & ELECTRIC CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19253B054	List: ML19253B053 ML19253B057
References
LER-79-030-03L, LER-79-30-3L, NUDOCS 7909140430
Download: ML19253B057 (1)

Text

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REPORT DATE EVENT OESCRIPTION AND PRO 9 ABLE CONSEQUENCES h o 2 L At 0250 durino the nerformance of a routine surveillance test. it was discovered I o 3 l that Control Element Assemblies (CEA's) 6, 7, 49, 51 and 53 failed to initiate a I o 4 CEA l'oition Inhibit (CMI) function when these CEAs deviated from their arouos by 1 Lo s I creater than 7.5 inches. The CEAs were fully withdrawn and the CEA drive system I o e I was raintained off as recuired by T.S.3.1.3.1. until the CEA circuit was reoaired I lo 7 l at 0835 on 8-5-79. LER 79-25 (U-2) describes a similar occurrence. I o 8 i I

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40 el 42 43 44 47 CAUSE OGSCRIPTION AND CORRECTIVE ACTIONS i o The CEA f*otion Inhibit setooint voltace levels were found to have drifted. This l i i l drift is considered to be a result of minor chanqes in electronic coroone-t t l characteristics due to acina and environmental effects. The setroints will be

, 3 7 l reduced as previcusly described in LER 79-25/3L for plant decket no. 50-318. I

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