Corethermal–hydraulicdesignOriginalResearchArticle

Thecorethermal–hydraulicdesignfortheHTTRiscarriedouttoevaluatethemaximumfueltemperatureatnormaloperationandanticipatedoperationoccurrences.Toevaluatecoolantflowdistributionandmaximumfueltemperature,weusetheexperimentalresultssuchasheattransfercoefficient,pressurelosscoefficientobtainedbymock-uptestfacilities.Furthermore,weevaluatedhotspotfactorsoffueltemperaturesconservatively. Astheresultsofthecorethermal–hydraulicdesign,aneffectivecoolantflowthroughthecoreof88%ofthetotalflow,isachievedatminimum.Themaximumfueltemperatureappearsduringthehigh-temperaturetestoperation,andreaches1492°Cforthemaximumthroughtheburn-upcycle,whichsatisfiesthedesignlimitof1495°Catnormaloperation.Itisalsoconfirmedthatthemaximumfueltemperatureatanyanticipatedoperationoccurrencesdoesnotexceedthefueldesignlimitof1600°Cinthesafetyanalysis. Ontheotherhand,resultofre-evaluationofanalysisconditionandhotspotfactorsbasedonoperationdataoftheHTTR,themaximumfueltemperaturefor160effectivefullpoweroperationdaysisestimatedtobe1463°C.Itisconfirmedthatthecorethermal–hydraulicdesigngivesconservativeresults.