ML19296A191

LER 79-001/03L-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

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: ML19296A189 ML19296A191
References
LER-79-001-03L, LER-79-1-3L, NUDOCS 7902130174
Download: ML19296A191 (1)

Text

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LICENSEE EVENT REPORT CornROLstOcx  ! l l l l l@ (PLE ASE PRINT OR TYPE ALL REG- ' RED INFORMATION) o i lM N lP lI lN l 2 l@l 0 l 0 l - l 0 l 0 l 0] 0l0 l- l0 l 0 lgl 4 l 1 ] 1 l 1,1l@l SI U l T 50jg 25 26 L IC E NSE TvPE 01 84 'l LIC E N5t L ( f/ 4 14 15 LICENSE NUYHEH CO*/ T o i "CC I Lj@l 0 l 5 l 0 l 0 l 0 l 3 l 0 l 6 j@l0 l1 l 1 l 2 l 7 9 l@)0 l2 10l9 719 l@

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loI.J During surveillance test it was f ound that instrument 2TM-404V, an overpower A T o ti I summing circuit, had drifted such that trip actuation from this channel could have l Redundant channels were operable. No j I o I 4 I Loccurred at 10.1% versus the limit of 107..

i Le f fec t on public health and safety. I O 6 l 0 /

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.13 C AUSE DESCRIPTION AND CORRECTIVE ACTIONS 1 o l Instrument drif t in a FoxbOro Model 66RC-OL Summing Unit. Device was immediately ;

li[i!l recalibrated. Performance of the device is being evaluated frequently to determine

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