Author/Authors :
Y.Ohoka، نويسنده , , H.Sekimoto، نويسنده ,
Abstract :
TheCANDLEburnupstrategy,wherethedistributionsoffuelnuclidedensities,neutronflux,andpowerdensitymovewiththesameconstantspeedandwithoutanychangeintheirshapes,isappliedtotheblock-typehightemperaturegascooledreactor.Ifitissuccessful,aburnupcontrolrodcanbeeliminated,andseveralmeritsareexpected.Thisburnupmayberealizedbyenricheduraniumandburnablepoisonwithlargeneutronabsorptioncross-section.Withthefuelenrichmentof15%,gadoliniumconcentrationof3.0%,andfuelcellpitchof6.6cm,theCANDLEburnupisrealizedwiththeburningregionmovingspeedof29cm/yearandtheaxialhalf-widthofpowerdensitydistributionof1.5m.Whentheconcentrationofnaturalgadoliniumishigher,theburningregionmovingspeedbecomesslowerandtheburnupbecomeshigher,thoughtheeffectiveneutronmultiplicationfactorbecomessmaller.WhenU-235enrichmentishigher,theeffectiveneutronmultiplicationfactorbecomeslarger,thespeedbecomesslower,andtheburnupbecomeshigher.Whenthepitchiswider,theeffectiveneutronmultiplicationfactorbecomeslarger,thespeedbecomesfaster,andtheburnupbecomeshigher.
