Realisticseismicqualificationusingtheupdatedfiniteelementmodelforin-corecomponentsofreactorsOriginalResearchArticle

Itisnowmandatorytoseismicallyqualifythesafety-relatedstructuresandcomponentsusedinthenuclearpowerplants.Amongseveralqualificationapproachesthequalificationbytheanalysisusingfiniteelement(FE)methodisthemostcommonapproachusedinpractice.However,theestimateddynamicbehaviourbyFEmodelofastructureisknowntoshowsignificantdeviationsfromthedynamicbehaviourofthe‘as-installed’structureinmanycases.Consideringsuchlimitations,fewresearchershaveadvocatedre-qualificationofsuchstructuresaftertheirinstallationatsitetoenhancetheconfidenceinqualificationvis-à-visplantsafety.Forsuchanexercise,validationofFEmodelwithexperimentalmodaldataisimportant.AvalidatedFEmodelcanbeobtainedbythemodelupdatingmethodsinconjugationwiththeinsituexperimentalmodaldata.Suchamodelcanthenbeusedforqualification.However,forthereactorin-corecomponentssuchamodaltestingandFEmodelupdatingmaynotbestraightforward.Hence,thecomplicationinvolvedinthereliableseismicqualificationofin-corecomponentsandtheadvantageofusingtheFEmodelupdatinghasbeenbroughtoutinthepaperthroughanexampleofatypicalin-corecomponent—aperforatedhorizontaltuberecentlyinstalledinanuclearreactorinIndia.