MoltensaltrelatedextensionsoftheSIMMER-IIIcodeanditsapplicationforaburnerreactorOriginalResearchArticle

Moltensaltreactors(MSRs)canbeusedaseffectiveburnersofplutonium(Pu)andminoractinides(MAs)fromlightwaterreactor(LWR)spentfuel.Inthispaperastudywasmadetoexaminethethermalhydraulicbehaviouroftheconceptualdesignofthemoltensaltadvancedreactortransmuter(MOSART)[Ignatiev,V.,Feynberg,O.,Myasnikov,A.,Zakirov,R.,2003a.Neutronicpropertiesandpossiblefuelcycleofamoltensalttransmuter.Proceedingsofthe2003ANS/ENSInternationalWinterMeeting(GLOBAL2003),HyattRegency,NewOrleans,LA,USA16–20November2003].ThemoltensaltfuelisaternaryNaF–LiF–BeF2systemfuelledwithca.1mol%typicalcompositionsoftransuranium-trifluorides(PuF3,etc.)fromlightwaterreactorspentfuel.TheMOSARTreactorcoredoesnotcontaingraphitestructureelementstoguidetheflow,sotheneutronspectrumisratherhardinordertoimprovetheburningperformance.Withoutthosestructureelementsinthecore,themoltensaltincoreflowsfreelyandtheflowpatterncouldbepotentiallycomplicatedandmayaffectsignificantlythefueltemperaturedistributioninthecore.Therefore,someoptimizationsofthesaltflowpatternmaybeneeded.Here,themainattentionhasbeenpaidtothefluiddynamicsimulationsoftheMOSARTcorewiththecodeSIMMER-III[Kondo,Sa.,Morita,K.,Tobita,Y.,Shirakawa,K.,1992.SIMMER-III:anadvancedcomputerprogramforLMFBRsevereaccidentanalysis.ProceedingsoftheANP’92,Tokyo,Japan;Kondo,Sa.,Tobita,Y.,Morita,K.,Brear,D.J.,Kamiyama,K.,Yamano,H.,Fujita,S.,Maschek,W.,Fischer,E.A.,Kiefhaber,E.,Buckel,G.,Hesselschwerdt,E.,Flad,M.,Costa,P.,Pigny,S.,1999.CurrentstatusandvalidationoftheSIMMER-IIILMFRsafetyanalysiscode.ProceedingsoftheICONE-7,Tokyo,Japan],whichwasoriginallydevelopedforthesafetyassessmentofsodium-cooledfastreactorsandrecentlyextendedbytheauthorsforthethermo-hydraulicandneutronicmodelssoastodescribethemoltensaltreactors.Fortheadaptationtomoltensaltreactor,acompleteequationofstate(EOS)forthisliquidfuelhadtobedevelopedandimplementedintotheSIMMER-IIIcode.Throughthosesimulationsitwasconcludedthatthethermalhydraulicbehaviourappearedtobeveryimportantinmoltensaltreactorsconcerningdesign,operationandsafety.Aflowdistributionplatedesignwasfoundeffectivetooptimizetheflowpatterninthecoreregion.Furtherinvestigationsareunderwaytoobtainoptimalflowfieldswithoutexceedingdesignlimits.