05000306/LER-1979-001-03, /03L-0 on 790112:during Surveillance Test Found That Instrument 2TM-404V,overpower delta-T Summing Circuit, Had Drifted Due to Drift in Foxbore Model 66RC-OL Summing Unit

/03L-0 on 790112:during Surveillance Test Found That Instrument 2TM-404V,overpower delta-T Summing Circuit, Had Drifted Due to Drift in Foxbore Model 66RC-OL Summing Unit

ML19296A191
Person / Time
Site:	Prairie Island
Issue date:	02/09/1979
From:	Hunstad A NORTHERN STATES POWER CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19296A190	List: 05000306/LER-1979-001, Forwards LER 79-001/03L-0 05000306/LER-1979-001-03, /03L-0 on 790112:during Surveillance Test Found That Instrument 2TM-404V,overpower delta-T Summing Circuit, Had Drifted Due to Drift in Foxbore Model 66RC-OL Summing Unit
References
LER-79-001-03L, LER-79-1-3L, NUDOCS 7902130174
Download: ML19296A191 (1)

LER-1979-001, /03L-0 on 790112:during Surveillance Test Found That Instrument 2TM-404V,overpower delta-T Summing Circuit, Had Drifted Due to Drift in Foxbore Model 66RC-OL Summing Unit

Event date:
Report date:
3061979001R03 - NRC Website

text

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Et ENT DFSCR PTION A DPROBAB C S QLENCES loI.J During surveillance test it was f ound that instrument 2TM-404V, an overpower A T j

o ti I summing circuit, had drifted such that trip actuation from this channel could have l I o I 4 I Loccurred at 10.1% versus the limit of 107..

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