Boilingwaterreactorwithinnovativesafetyconcept:TheGenerationIII+SWR-1000OriginalResearchArticle

AREVANPhasdevelopedaninnovativeboilingwaterreactor(BWR)SWR-1000inclosecooperationwithGermannuclearutilitiesandwithsupportfromvariousEuropeanpartners.ThisGenerationIII+reactordesignmarksanewerainthesuccessfultraditionofBWRand,withanetelectricaloutputofapproximately1250MWe,isaimedatensuringcompetitivepowergeneratingcostscomparedtogasandcoalfiredstations.Itisparticularlysuitableforcountrieswhosepowernetworkscannotfacilitatelargepowerplants.Atthesametime,theSWR-1000meetsthehighestsafetystandards,includingcontrolofcoremeltaccidents.Theseobjectivesaremetbysupplementingactivesafetysystemswithpassivesafetyequipmentofvariousdesignsforaccidentdetectionandcontrolandbysimplifyingsystemsneededfornormalplantoperationonthebasisofpastoperatingexperience.Theplantisalsoprotectedagainstairplanecrashloads. Thefunctionalcapabilitiesandcapacitiesofallnewsystemsandcomponentsweresuccessfullytestedunderrealisticandconservativeboundaryconditionsinlarge-scaletestfacilitiesinFinland,SwitzerlandandGermany. Ingeneral,theSWR-1000designisbasedonwell-provenanalyticalcodesanddesigntoolsvalidatedforBWRapplicationsthroughrecalculationofrelevantexperimentsandindependentlicensingactivitiesperformedbyauthoritiesortheirexperts.Theoverviewofusedanalyticalcodesanddesigntoolsaswellasperformedexperimentalvalidationprogramsispresented. Effectiveimplementationofpassivesafetysystemsisdemonstratedthroughthenumericalsimulationoftransientsandlossofcoolantaccidents(LOCAs)aswellasthroughanalyticalsimulationofasevereaccidentassociatedwiththecoremelt.IntheLOCAsimulationpresentedtheexistingactivecorefloodingsystemswerenotusedforemergencycontrol:onlypassivesystemswererelevantfortheanalyses.Despitethis–nocoreheat-upoccurred.Inthecaseofreactorcoremeltingnumericallyisdemonstratedthatthemoltencoredebriswouldberetainedinsidethereactorvesselduetotheeffectivepassiveexternalwatercoolingofthevessel,keepingitcompletelyintact. Ashortconstructionperiodofjust48monthsfromfirstconcretetoprovisionaltakeover,flexiblefuelcyclelengthsofbetween12and24monthsandahighfueldischargeburn-upallcontributetowardsmeetingeconomicgoals.Realisticaverageavailabilityforaplantlifetimeof60yearsand12monthscycleis94.5%.SystemsandplantdesignwerereviewedbyexpertgroupsofEuropeanutilities.WiththeSWR-1000,AREVANPhasdevelopedadesignconceptforaBWRplantthatisnowreadyforcommercialdeploymentandwhichfullymeetsthemoststringentinternationalrequirementsintermsofnuclearsafetyandnuclearregulatory.