On-linemonitoringtheincorepowerdistributionbyusingexcoreion-chambersOriginalResearchArticle

Formostofnowadaypressurizedwaterreactors(PWR),excoreion-chambers(EIC)arethesolereal-timesensorsrespondingtotheincorepowerdistribution(IPD).Conventionally,itissupposedthattheEICcouldnotcarryoutinformationoftheIPDinradialdirection.Asaresult,thereisanexcessconservatismwhentheyarebeingusedforthecoremonitoringsofar,andsomeflexibilitiesofthereactoroperationaresacrificed.Thoughprogresseshavebeenmade,therearestillsomeinevitableobstaclesaboutnewlydevelopedmonitoringmethods:mountingandmaintainingalargeamountoffixedincoredetectorsarecostly;andtheIPDcalculatedbyon-linesimulatorsisnotthe“measured”one.FortunatelyvariationsintheIPDmustbedrivenbyreasonablephysicalcauses,andthecorrespondingvariationsinthereadingsoftheEICarenotableenoughtobeidentified.SowithaspecificreferencedIPDmeasuredfromperiodicalfluxmappings,itispossibletoon-linemonitorsuchvariationsbyusingtheEIC.Aimedatthis,aharmonicsgroupingmethodandanalgorithmofhigherorderperturbationvariablesaredeveloped,andaninfluenceequationforcontrolrodsisalsoproposed.ThenapreciserestrictionequationdescribingthereasonablevariationsintheIPDisdeducedforexampleoftheHeatingReactor.Combinedwithaproper-configuredEIC,asystematic“excore-to-incore”methodisrealizedfinally.