TransienttestsonblowertripandrodremovalattheHTR-10OriginalResearchArticle

Safetydemonstrationtestsonthe10MWhightemperaturegas-cooledreactortestmodule(HTR-10)wereconductedtoverifytheinherentsafetyfeaturesofMHTGRsandtoobtainthecoreandprimarycoolingsystemtransientdataforvalidationofsafetyanalysiscodes. Twosimulatedanticipatedtransientswithoutscram(ATWS)tests,loseofforcedcoolingbytripoftheheliumblowerandreactivityinsertionviacontrolrodwithdrawalwereperformed.Thispaperdescribesthetestswithdetailedtestmethod,conditionandresults. Calculatedresultsshowthatthestronglynegativetemperaturecoefficientcausesreactorpowertocloselyfollowheatremovallevels.Maximumfueltemperaturechangesarelimitedbythelargecoreheatcapacitytobelow1230°Cduringtwotests. ThetestoftrippingtheheliumcirculatorATWStestwasconductedonOctober15,2003.Althoughnoneof10controlrodswasmoved,thereactorpowerimmediatelydecreasedduetothenegativetemperaturecoefficient.Afterabout50min,thereactorbecamecriticalityagain.Finally,thereactorpowerwenttoastablelevelwithabout200kW. ThetestofreactivityinsertionATWStestwasconductedtwotimes.Followingthecontrolrodwithdrawal,thereactorpowerincreasedrapidly,themaximumpowerlevelreachedto5037and7230kWfromtheinitialpowerof3000kWinaccordancewithreactivityinsertionof$0.136and0.689,respectively.Afterthereactivityintroducedwascompensatedbymeansofthestrongnegativereactivityfeedbackeffect,thereactorwenttosubcriticalandthepowerdecreased.