核电厂数字化仪控系统动态概率安全评价方法-研究

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1、AbstractDynamicprobabilisticsafetyassessment(PSA)methodologiesaledefinedasthosethatcallaccountforthecouplingbetweenthetriggeredorstochasticlogicaleventsinsystemreliabilitymodelingthroughexplicitconsiderationofthetimeelementinsystemevolution．DynamicPSAcallovercomet

2、heshortcomingoftraditionalPSAmethodologiesandeffectivelyvalidatethereliabilityandsafetyofdigitalinstrumentationandcontrolsystems．Twomethodologies，i．e．，Markov／Cell-to—CellMappingTechnique(Markov／CCMT)andDynamicFlowgraphMethodology(DFM)havebeeninvestigated，whicharet

3、womostappropriatetechniquesforthereliabilityandsafetymodelingofdigitalinstrumentationandcontrolsystemsthatwereproposedbyNuclearRegulatoryCommissionreportNUREG／CR-6901．Supposethatasmall··breaklossofcoolantaccidentofmainfeed--waterpipinghappenswhenthesystemisunderfu

4、llpoweroperating，weconductthePSAfortheAPI000mainfeed-watersystemwiththeMarkov／CCMTmethodology．IntheprocessofPSA，amainfeed-waterpumpandamainfeed-waterregulatingvalvehavebeenchosenasthefailurecomponents．Firstly,thetransitionprobabilitiesofthecomponentstatecombinatio

5、nshavebeencalculated．Thenallthepossiblefailurescenarioshavebeenconsideredaccordingtothesystemstatesandsimulatethesescenarioswithsystemmodelbuilton3KeyMastersimulationplatform．Thenextstepistocalculatethecelltransitionprobabilities．Atlast，theprobabilitiesofthetopeve

6、nts，steamgeneratoratlowlevelandsteamgeneratorathighlevelhavebeenobtained．ThroughtheMarkov／CCMTmethodology,someimportantfailurecasesCanbeavoidedfrombeinglost，thecompetitionoftopeventscanbesolved，andtheaccuratetimeforfailuresCanbeobtainedaswell．Inthisstudy,theimpact

7、onsteamgeneratorwaterlevelatfullpowerlevelhasbeenconsideredduetocomponentsfailureinmainfeed-watersystemofCPRl000．AndtheDFMmethodologyhasbeenconductedtoimplementPSAanalysis．Firstly,IIchoosethecriticalsystemphysicalvariables，andconstructdecisiontablesanddiscretenode

8、statesaccordingtothedataproducedbythesimulationplatformofCPRl000nuclearpowerplant，andthenthedeductiveanalysisandinductiveanalysisaccordingtotheconstruct