AstudyonevaluatingapassiveautocatalyticrecombinerPAR-systeminthePWRlarge-drycontainmentOriginalResearchArticle

Asystematicstep-by-stepframeworkforanalyzinghydrogenbehaviorandimplementingpassiveautocatalyticrecombiners(PARs)tomitigatehydrogendeflagrationordetonationriskinsevereaccidents(SAs)ispresented.Theprocedurecanbesubdividedintofivemainsteps:(1)modelingthecontainmentbasedontheplantdesigncharacteristics,(2)selectingthetypicalsevereaccidentsequences,(3)calculatingthehydrogengenerationincludingin-andex-vesselperiod,(4)modelingthegasdistributionincontainmentatmosphereandestimatingthehydrogencombustionmodesand(5)evaluatingtheefficiencyofthePAR-systemtomitigatethehydrogenriskwithandwithoutcatalyticrecombiners,accordingtothesafetycriterion.FortheChinese600MWepressurizedwaterreactor(PWR)withalarge-drycontainment,largebreakloss-of-coolantaccident(LB-LOCA)isscreenedoutasthereferencesevereaccidentsequence,consideringthenatureofhydrogengenerationandtheprobabilisticsafetyassessment(PSA)resultonaccidentsequences.Theresultsshowthatacertainnumberofrecombinerscouldremoveeffectivelyhydrogenandoxygen,toprotectthecontainmentintegrityagainsthydrogendeflagrationordetonation.