Thermal-hydrauliccalculationsusingMARScodeappliedtolowpowerandshutdownprobabilisticsafetyassessmentinaPWROriginalResearchArticle

Themethodsdevelopedforfull-powerprobabilisticsafetyassessment,includingthermal-hydraulicmethods,havebeenwidelyappliedtolowpowerandshutdownconditions.Experiencefromcurrentlowpowerandshutdownprobabilisticsafetyassessments,however,indicatesthatthethermal-hydraulicmethodsdevelopedforfull-powerprobabilisticsafetyassessmentsarenotalwaysreliablewhenappliedtolowpowerandshutdownconditionsandconsequentlymayyieldmisleadingandinaccurateriskinsights.Toincreasetheusefulnessofthelowpowerandshutdownriskinsights,thecurrentmethodsandtoolsusedforthermal-hydrauliccalculationsshouldbeexaminedtoascertainwhethertheyfunctioneffectivelyforlowpowerandshutdownconditions.Inthisstudy,aplatformforrelativelydetailedthermal-hydrauliccalculationsappliedtolowpowerandshutdownconditionsinapressurizedwaterreactorwasdevelopedbasedonthebestestimatethermal-hydraulicanalysiscode,MARS2.1.ToconfirmtheapplicabilityoftheMARSplatformtolowpowerandshutdownconditions,manythermal-hydraulicanalyseswereperformedfortheselectedtopic,i.e.thelossofshutdowncoolingeventsforvariousplantoperatingstatesattheKoreanstandardnuclearpowerplant.Theplatformdevelopedinthisstudycandealeffectivelywithlowpowerandshutdownconditions,aswellasassisttheaccidentsequenceanalysisinlowpowerandshutdownprobabilisticsafetyassessmentsbyprovidingfundamentaldata.Consequently,theresultinganalysesmayyieldmorerealisticandaccuratelowpowerandshutdownriskinsights.