搜索
U.S.NUCLEARREGULATORYCOMMISSIONFebruary1972Revision0REGULATORYGUIDEOFFICEOFNUCLEARREGULATORYRESEARCHREGULATORYGUIDE1.22(DraftwasissuedasSafetyGuide22)PERIODICTESTINGOFPROTECTIONSYSTEMACTUATIONFUNCTIONSA.INTRODUCTIONGeneralDesignCriterion20ofAppendixAto10CFRPart50,“GeneralDesignCriteriaforNuclearPowerPlants,”requiresthattheprotectionsystembedesignedtoinitiatetheoperationofsystemsandcomponentsimportanttosafety.GeneralDesignCriterion21requiresthattheprotectionsystembedesignedtopermitperiodictestingofitsfunctioningwhenthereactorisinoperation.Incurrentdesignstheabilityoftheprotectionsystemtoinitiatetheoperationofsafetysystemsdependsontheproperperformanceofactuationdevices;therefore,thesedevicesaretobetested.Thissafetyguidedescribesacceptablemethodsofincludingtheactuationdevicesintheperiodictestsoftheprotectionsystemduringreactoroperation.Itdoesnotaddressthefrequencyofsuchtesting.B.DEFINITIONSprotectionsystem—Theprotectionsystem,asdefinedinIEEEStd279-1971,1encompassesallelectricandmechanicaldevicesandcircuitry(fromsensorstoactuationdeviceinputterminals)involvedingeneratingthosesignalsassociatedwiththeprotectivefunction.1CopiesofIEEEStd279-1971,“CriteriaforProtectionSystemsforNuclearPowerGeneratingStations,”maybeobtainedfromtheInstituteofElectricalandElectronicsEngineers,UnitedEngineeringCenter,345East47thStreet,NewYork,NewYork10017.TheNRCissuesregulatoryguidestodescribeandmakeavailabletothepublicmethodsthattheNRCstaffconsidersacceptableforuseinimplementingspecificpartsoftheagency’sregulations,techniquesthatthestaffusesinevaluatingspecificproblemsorpostulatedaccidents,anddatathatthestaffneedsinreviewingapplicationsforpermitsandlicenses.Regulatoryguidesarenotsubstitutesforregulations,andcompliancewiththemisnotrequired.MethodsandsolutionsthatdifferfromthosesetforthinregulatoryguideswillbedeemedacceptableiftheyprovideabasisforthefindingsrequiredfortheissuanceorcontinuanceofapermitorlicensebytheCommission.Thisguidewasissuedafterconsiderationofcommentsreceivedfromthepublic.Regulatoryguidesareissuedin10broaddivisions:1,PowerReactors;2,ResearchandTestReactors;3,FuelsandMaterialsFacilities;4,EnvironmentalandSiting;5,MaterialsandPlantProtection;6,Products;7,Transportation;8,OccupationalHealth;9,AntitrustandFinancialReview;and10,General.ElectroniccopiesofthisguideandotherrecentlyissuedguidesareavailablethroughtheNRC’spublicWebsiteundertheRegulatoryGuidesdocumentcollectionoftheNRC’sElectronicReadingRoomat’sAgencywideDocumentsAccessandManagementSystem(ADAMS)at—Acomponentorassemblyofcomponentsthatdirectlycontrolsthemotivepower(electricity,compressedair,etc.)foractuatedequipment.Thefollowingareexamplesofanactuationdevice:acircuitbreaker,arelay,andavalve(anditsoperator)usedtocontrolcompressedairtotheoperatorofacontainmentisolationvalve.actuatedequipment—Acomponentorassemblyofcomponentsthatperformsordirectlycontributestotheperformanceofaprotectivefunctionsuchasreactortrip,containmentisolation,oremergencycoolantinjection.Thefollowingareexamplesofactuatedequipment:anentirecontrolrodanditsreleasemechanism,acontainmentisolationvalveanditsoperator,andasafetyinjectionpumpanditsprimemover.C.DISCUSSIONOnefunctionoftheprotectionsystemistoinitiatetheoperationofsystemsandcomponentsimportanttosafety.Itisrequiredthattheprotectionsystembedesignedtopermitperiodictestingofitsabilitytoperformtheseinitiationfunctionswhenthereactorisinoperation.Basedonthereviewofseveralapplicationsforconstructionpermitsandoperatinglicenses,theregulatorystaffhasconcludedthatthepreferablemethodofimplementingthisrequirementistodesigntheprotectionsystemsuchthat-theactuationdevicesandactuatedequipmentareperiodicallytestedwiththeprotectionsystemduringreactoroperation.Generallyithasbeenindustrypracticetoincludetheactuationdevicesintheperiodictestsofthatportionoftheprotectionsystemusedtoinitiatereactortrip.Earlydesignsdidnotprovidethissamedegreeoftestabilityinthoseportionsoftheprotectionsystemusedtoinitiatetheoperationofengineeredsafetyfeatures,standbypowersupplies,andothersupportingsystems.Itisrecognizedthatprovidingthecapabilitytotesttheactuationdevicesfortheselattersystemscanpresentdifferentdesignproblems.Nevertheless,GeneralDesignCriterion21requiresthesamehighdegreeofinservicetestabilityinallportionsoftheprotectionsystem.Inthecaseofsomeengineeredsafetyfeaturesystems,testingtheoperationoftheentiregroupofactuatedequipmentassociatedwithaprotectivefunctionmaydamageplantequipmentordisruptreactoroperation.Inthesecases,acceptablemethodsofincludingtheactuationdevicesinperiodictestsoftheprotectionsystem,whileavoidingtheundesirableeffectsofoperationoftheactuatedequipment,are:(1)testingtheactuationdevicesandtheactuatedequipment2individuallyorinjudiciouslyselectedgroups,(2)preventingtheoperationofcertainactuatedequipmentduringatestoftheiractuationdevices,and(3)designingthesystemsuchthatoperationoftheactuatedequipmentrequire