RG1.083 PWR SG传热管的在役检查 1975

Revision1July1975U.S.NUCLEARREGULATORYCOMMISSIONREGULATORYGUIDEOFFICEOFSTANDARDSDEVELOPMENT'REGULATORYGUIDE1.83INSERVICEINSPECTIONOFPRESSURIZEDWATERREACTORSTEAMGENERATORTUBESA.INTRODUCTIONGeneralDesignCriteria14,ReactorCoolantPressureBoundaryand31,FracturePreventionofReactorCoolantPressureBoundary,ofAppendixA,GeneralDesignCriteriaforNuclearPowerPlants,to10CFRPart50,UcensingofProductionandUtilizationFacilities,'requirethatthereactorcoolantpressureboundaryhaveanextremelylowprobabilityofabnormalleakage,ofrapidlypropagatingfailure,andofgrossrupture.GeneralDesignCriterion15,ReactorCoolaniSystemDesign,requiresthatthereactorcoolantsystemandassociatedauxiliary,control,andprotectionsystemsbedesignedwithsufficientmargintoensurethatthedesignconditionsofthereactorcoolantpressureboundaryarenotexceededduringanyconditionofnormaloperation,includinganticipatedoperationaloccurrences.Furthermore,GeneralDesignCriterion32,InspectionofReactorCoolantPressureBoundary,requiresthatcomponentsthatarepartofthereactorcoolantpressureboundarybedesignedtopermitperiodicinspectionandtestingofcriticalareastoassesstheirstructuralandleaktightintegrity.Failure'ofsteamgeneratortubes,whichcanbecausedbycracking,wastage,andfretting,willreleaseradioactivematerialstothesecondarycoolantsystem.Furthermore,seriousweakeningofthesetubesfromsimilarcausescould,intheeventofaloss-of-coolantaccident(LOCA),resultintubefailuresthatwouldreleasetheenergyofthesecondarysystemintothetFailureisdefinedasfullpenetrationofthepressureboundarywithsubsequentleakage.containment.ThisguidedescribesamethodacceptabletotheNRCstaffforimplementingtheseGeneralDesignCriteriabyreducingtheprobabilityandconsequencesofsteamgeneratortubefailuresthroughperiodicinserviceInspectionforearlydetectionofdefectsanddeterioration.Thisguideappliesonlytopressurizedwaterreactors(PWRs)..TheAdvisoryCommitteeonReactorSafeguardshasbeenconsultedconcerningthisguideandhasconcurredintheregulatoryposition.B.DISCUSSIONTheheattransferareaofthesteamgeneratorsinpressurizedwaterreactorscancomprisewellover50%oftheareaofthetotalprimarysystempressure-retainingboundary.Thethin-walledsteamgeneratortubingisanimportantpartofamajorbarrieragainstfissionproductreleasetotheenvironment.ThesteamgeneratortubingalsoactsasabarrieragainststeamreleasetothecontainmentintheeventofaLOCA.Toactasaneffectivebarrier,thistubingmustbefreeofcracks,perforations,andgeneraldeterioration.ThedesigncriteriausedtoestablishthestructuralintegrityofthesteamgeneratortubingshouldalsodefinetheminimumtubewallthicknessrequiredtosustainthepressureandthermalloadingcausedbytheworstpostulatedLOCAincombinationwithasafeshutdownearthquake.2InadequatecontrolofthesecondarycoolantchemistryhasbeenidentifiedasoneoftheprincipalsourcesAsdefinedinAppendixA,SeismicandGeologicSitingCriteriaforNuclearPowerPlants,to10CFRPart100,ReactorSiteCriteria.USNRCREGULATORYGUIDESCommentsshouldbesenttotheSecretaryoftheCommission.U.S.NuclearRegulatoryGuidesareissuedtodescribeandmakeavailabletothepublicRegulatoryCommission.Washington.D.C.2V565.Attention:Dock[e-mail]'sregulations,todelineatetechniquesusedbythestaffinevalu-Theguidesareissuedinthefollowingtenbroaddivisions:atingspecificproblemsorpostulatedaccidents,ortoprovideguidancetoapplicents.RegulatoryGuidesarenotsubstitutesforregulations.andcompliance1.PowerReactors.Productswiththemisnotrequired.Methodsandsolutionsdifferentfromthosesetoutin2.ResearchendTestReactors7.Transportationtheguideswillbeacceptebleiftheyprovidesbasisforthefindingsrequisiteto3.FuelsandMaterialsFacilitiesS.OccupationalHealththeissuanceorcontinuanceofapermitorlicensebytheCommission.4.EnvironmentalandSiting9.AntitrustReviewCommentsendsuggestionsforimprovementsintheseguidesareencouragedSMaterialsandPlantProtection10Generalotalltimes,andguideswillberevised,asappropriate.toaccommodatecammentsandtoreflectnewinformationoresperience.ThisguidewasrevisedasaCopiesofpublishedguidesmaybeobtainedbywrittenrequestindicatingtheresultofsubstantivecommentsreceivedfromthepublicandadditionalstaffdivisionsdesiredtotheU.S.NuclearRegulatoryCommission.Washington.D.C.review.2055.Attention:Director.OfliceofStandardsDevelopment.ofsteamgeneratortubedegradationandfailure.Thereisevidencethatexcessivesteam-sidecorrosionattackoccursinrestrictedflowareasthatpermithighlocalconcentrationoffreecaustic,phosphates,andImpuritiesthatmayenterthesteamgeneratortnruugh'concenserinleakage.Therefore,secondarywaterchemistryspecificationsmustreflectthelimitationofthematerialsinthesecondarysystem,andthesupportingauxiliarychemicalfeedsystemmustbedesignedtomaintaindesiredfeedwaterqualitytoeachsteamgenerator.Effectivemonitoringofwaterchemistrywithin-linecontinuousanalyticalinstrumentationsupplementedbyplantlaboratorysamplinganalysisofsteam,condensatereturn,andfeedwaterisnecessaryatalltimesduringoperationtoensurethatwaterqualityisnotdegradedbelowacceptablelimitsbysucheventsascondenserinleakageorchemicalfeedsystemmaloperation.Mechanica