ML20039C860

LER 81-044/03L-0:on 811124,appropriate DNBR Penalty Factors Were Not Included in Core Operating Limits Supervisory Sys & Core Protection Calculator Calculations.Caused by Failure to Incorporate Vendor Recommendation in Tech Specs

ML20039C860
Person / Time
Site:	Arkansas Nuclear
Issue date:	12/23/1981
From:	Rogers P ARKANSAS POWER & LIGHT CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20039C859	List: ML20039C858 ML20039C860
References
LER-81-044-03L, LER-81-44-3L, NUDOCS 8112310021
Download: ML20039C860 (2)

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8 W 61 DQCat & T Debug t R f v t N, D.) E EVENT DESCRIPTION AND PROB ASLE CONSEQUENCES h to12i i On 11/24/81 while in Mode 1 operation at 100% full power, it was discovert-r o ia l I ed. while cerfoming the surveillanco fnr T 9 a '> 4 a _ tha t thn acoroori-1 _

go i. i i ate DNBR penalty factors were not being included in the Core Operating l o s i Limits Supervisory System (COLSS) and Core Protection Calculator (CPC)I e 6 1 DNBR Calculations. As a result the reactor Eas_ operating outside the 1 ic i,i i acceptable region described in T.S.3.2.4. This occurrence did not signi-i i c i ., i iimpact acceptability due to the small effect ( 0.lQ._ Reportable per T.S.i sML s" Vs! wo,0~imoo, d.";L J',%

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, 2 i sequently, a method for conducting the surveillance required by Tech. I gi Spec. 4.2.4.4 was not incorporated until 11/24/81 (Core Average Burnup ofi gi 3730 MWD /MTU). On the same day of discovery, the BERR 1 factor used in i

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LER NO. 50-368/81-044/03L-0 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS (continued) the DNBR calculations was changed in all CPC channels to incorporate the appropriate rod bow penalty. COLSS was also updated to reflect the increased rad bow penalty. The surveillance procedure used to monitor core power distribution has been modified to incorporate the monitoring of rod bow penalty acceptabili ty. Completion of NRC review of the C-E rod bow penalty topical report should allow deletion of the additional penalties presently required by T.S.4.2.4.4 l

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