RG1.093 电力电源的可用性 1974

U.S.ATOMICENERGYCOMMISSIONREGULATORYDIRECTORATEOFREGULATORYSTANDARDSDecember1974GUIDEREGULATORYGUIDE1.93AVAILABILITYOFELECTRICPOWERSOURCESA.INTRODUCTIONSection50.36(cX2),LimitingConditionsforOperation,of10CFRPart50,LicensingofProductionandUtilizationFacilities,requirestheTechnicalSpecificationstoincludethelimitingconditionsforoperation(LCO)andactionsrequiredtobetakenbythelicenseewhentheLCOisnotmet.PoweroperationmaybeinitiatedandcontinuedwithoutrestrictiononlywhentheLCOismet.ThisguidedescribesoperatingproceduresandrestrictionsacceptabletotheRegulatorystaffwhichshouldbeimplementediftheavailableelectricpowersourcesarelessthantheLCO.Thisguideisapplicabletosingleandmulti-unitplants,includingmulti-unitplantsthatsharetherequiredelectricpowersources.TheLCOwithrespecttoavailableelectricpowersourcesisanelectricpowersystemthatsatisfiesGeneralDesignCriterion17(GDC-l7),ElectricPowerSystems,ofAppendixA,GeneralDesignCriteriaforNuclearPowerPlants,of10CFRPart50byincludingthefollowingelectricpowersources:(1)twophysicallyindependentcircuitsfromtheoffsitetransmissionnetwork,eachofwhichiseithercontinuouslyavailableorcanbemadeavailablewithinafewsecondsfollowingaloss-of-coolant.accident(LOCA),(2)redundantonsitea.c.powersupplies,and(3)redundantonsited.c.powersupplies.Nuclearpowerplw)tswhereinonlyoneofthetworequiredoffsitecircuitscanbemadeavailablewithinafewsecondsfollowingaLOCAareoutsidethescopeofthisguide.However,therestrictionsimposedonsuchplantsonthelossofrequiredsourceswouldgenerallybemorestringentthanthoserecommendedinthisguide.B.DISCUSSIONElectricloadsimportanttosafetyofnuclearpowerplantsareservedbyanelectricpowersystemthatconformstoGDC-17.PlantswithmorepowersourcesthanarerequiredbyGDC-17cantoleratethelossofoneormoresourcesandstillmeettheLCO.Duringthenormalcourseofoperation,however,anynuclearpowerplantmaylosepowersourcestotheextentthattheLCOisnotmet.Thisguideaddressessuchcases.GDC-17specifiesdesignrequirements,notoperatingrequirements;itthereforedoesnotstipulateoperationalrestrictionsonthelossofpowersources.Nevertheless,operationalrestrictionsbasedontheintentofGDC-17onthelossofpowersourceshavebeenincludedintheTechnicalSpecificationsofrecentlylicensednuclearpowerplants.Suchrestrictionsarebasedonthe-followingassumptions:*TheLCOofnuclearpowerplantsismetwhenalltheelectricpowersourcesrequiredbyGDC-17areavailable.*Undercertainconditions,itmaybesafertocontinueoperationatfullorreducedpowerforalimitedtimethantoeffectanimmediateshutdownonthelossofsomeoftherequiredelectricpowersources.Suchdecisionsshouldbebasedonanevaluationthatbalancestherisksassociatedwithimmediateshutdownagainstthoseassociatedwithcontinuedoperation.If,onbalance,immediateshutdownisthesafercourse,theunitshouldbebroughtpromptlytoanorderlyshutdown,andtoacold-shutdownstateassoonaspossible.Forexample,therisksassociatedwithanimmediateshutdownonthelossofonsitea.c.powersupplyduringaperiodoflightsystemloadwouldtendtobelessthanthoseduringapeakloadperiodbecausethestabilityoftheoffsitepowersystemwouldberelativelyhigher.If,onbalance,continuedpoweroperationisthesafercourse,theperiodofcontinuedoperationshouldbeusedtorestorethelostsourceandtoprepareforanorderly,shutdown,provided,ofcourse,thattheseactivitiesdonotriskfurtherdegradationoftheelectricpowersystemorinanywayjeopardizeplantsafety.*IftheLCOhasnotbeenachieved,theunitshouldbepromptlybroughttoanorderlyshutdownaftertheUSAECREGULATORYGUIDESCopiesofpublshedguidesmaybeobtoeludbyrequestIndicatingthediisondesiredtotheUS.AtomicEnergyCommission.Washington,D.C.20545,RegulatoryGuideswmissuedtodescribeamdmalkeavailabletothepublicAttention:DirectorofRegulatoryStenderds.Comnentsandsuggtionsformethodsc*WtebltotheAECRegulatorystaffofimplementingspecificpartsofimprovenentsintheseguidesweencouragedandshouldbesewttotheSecretarytheCommission'sregulations,todelineetstechniquesndbyVihstaffinoftheCommission,US.AtomicEnergyCommission,Washington.D.C.20545,evisluatingspecificproblemsorpostulatedaccidents,ortoprovideguidancetoAttention.DocicatingendServiceSection.appicantsRegulatoryGuidesmanotsubstitutesforregulationsandcompllancewiththemisnotrequired.MethodsandsolutionsdifferentfromthosesetoutinTheguidesaeissuedInthefollowingtonbroaddivisions:theguldaswillbeacceptebleiftheyprovideabesisforthefindingsrequisitetothebuanmorcontinuanceofapermitorlicensbytheCommission.1.PoWANReactors6.Products2.RlesseriarndTestReactors7.Transportation3.FuelsendMaerialsFacilitiesS.OccupationalHealthPublishedguideswillberevisedperiodically,asappropriate,toaccommodate4.EnvironmentalandSiring9.AntitrustReviewcommentsandtoreflectnewinformntionoresperience.5.MaterialsandPlantProtection10.Genralallowedtimeforcontinuedpoweroperationhaselapsedandtoacold,shutdownstateassoonaspossiblethereafter.Thepremisehereisthatthetimeallowedforcontinuedoperationcouldhavebeenusedtoenhancethesafetyoftheimminentshutdown.Forexample,thedispatchercouldtakesuchsystem-wideactionsasincreasinggenerationatotherplantsordroppingselectedloadstoensurethattheshutdowndoesnotcausegridinstability.Inaddition,iftheloss