Abstract :
Anewsteady-statefastneutrontestreactorhasbeenconceptuallydesigned.ThispaperpresentsanewconceptforaCANDU-basedfasttestreactorthatishorizontalinorientation,withindividualpressure/Calandriatubes(PT/CT)runningtheentirelengthofthescattering-mediumtank(Calandria)filledwithLead-Bismuth-Eutectic(LBE).Thisapproachforatestreactorwillprovidemoreflexibilityinrefueling,sampleremoval,andabilitytocompletelyreconfigurethecoretomeetdifferentusers’requirements.Fullcoreneutronicanalysisshowedasmallhexagonalreactor,LBE-cooled,trans-uranics(TRU)-67ZrfuelwithHT-9claddingandstructures,withacorepowerof100MWthproducedafastflux(>0.1MeV)of1.4×1015n/cm2saveragedoverthewholelengthofsixirradiationchannelswithatotaltestingvolumeofmorethan77l.LoadingofTRUfromlegacyUO2spentfuelallowedcorecontinuousoperationfor180effectivefullpowerdayswithanetfissile-Puburningrateof∼6.4%.SincehighneutronfluenceimpactonPT/CTmightbeanissueofconcernforthisdesign,oxidedispersionstrengthened(ODS)ferriticsteelwasusedasPT/CTmaterialwithoutanyimpactoncoreneutronicbehavior.Aninnovativeshutdown/controlsystemwhichconsistedofthesixoutermostfuelchannelswasproventobeeffectiveinshuttingthecoredownwhenfloodedwithboricacidasaneutronabsorber.Thenewshutdown/controlsystemhastheadvantageofcausingtheminimumperturbationoftheaxialfluxshapewhenthecontrolchannelsarepartiallyfloodedwithboricacid.Apreliminarythermal-hydraulicanalysisofLBEproducedacceptablepumpingpowerandcladtemperature.VoidingthecorefromitsLBEcoolantresultedinapositivereactivityinsertionwhichistypicalofmostfastreactors.HypotheticalaccidentsofdrainingtheCalandriaand/ortheexternalLBEreflectortankoftheLBEcoreresultedinnegativereactivityinsertionwhichshutthereactordown.
