ML17261A676
| ML17261A676 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 10/31/1987 |
| From: | ROCHESTER GAS & ELECTRIC CORP. |
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| ML17261A675 | List: |
| References | |
| PROC-871031, NUDOCS 8711300246 | |
| Download: ML17261A676 (55) | |
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ROCHESTERGAS6cELECTRICCOMPANYGINNANUCLEARPOWERPLANTSTEAMGENERATORHYDRAULICSNUBBERREPLACEMENTPROGRAMOCTOBER1987Revision1a7'S>30Oae6eVSCiOt~PDRADO'500D240PDR~(
TABLEOFCONTENTSSectionTitlePage1.02.03.04.05.06.0LISTOFTABLESLISTOFFIGURESINTRODUCTION1.1ExistingDesign1.2ProgramOverview1.3AnticipatedBenefits1.4PrimarySystemQualification1.5IntentofReportDESIGNLOADSANDCRITERIA2.1DesignBasisLoads2.1.1LoadingConditions2.1.2PostulatedPipeRuptures2.2GeneralCriteriaPRIMARYSYSTEMANALYSIS3.1PipingAnalysis3.1.1MathematicalModels3.1.2Methodology3.1.3ComputerPrograms3.1.4SupportStiffnesses3.1.5PipingEvaluationCriteria3.1.6PipingLoadCombinations3.2PrimaryEquipmentSupportsEvaluation3.2.1Methodology3.2.2SupportLoadingsandLoadCombinations3.2.3EvaluationCriteria3.2.4ComputerProgramsEVALUATIONANDRESULTS4.1ReactorCoolant.LoopPiping4.2ApplicationofLeak-Before-Break4.3MainSteamLineBreakLocations4.4PrimaryEquipment.Supports4.5PrimaryComponentNozzleLoadConformance4.6EvaluationofAuxiliaryLines4.7BuildingStructuralEvaluation4.7.1EvaluationofLocalAreas4.7.2SecondaryShieldWalls4.7.3ConclusionsADDITIONALCONSIDERATIONS5.1OvertemperatureEventQUALITYASSURANCEiv1-1l-ll-l1-31-3.1-42-12-12-12-22-43-13-13-13-23-43-43-63-63-73-73-73-83-84-14-14-14-14-24-24-34-34-34-44-45-15-16-13.3.
I" TABLEOFCONTENTS(cont'd.)SectionTitlePage
7.0CONCLUSION
S
8.0REFERENCES
tAPPENDIXACombinationofSeismicModalResponses7-18-1A-1 LISTOFTABLESTablel:Table2:Table3:TableTable7~8:Table4:Table5:Table6:RCSPipingLoadCombinationsandStressLimitsDefinitionofLoadingConditionsforPrimaryEquipmentEvaluationLoadCombinationsandAllowableStressLimitsforPrimaryEquipmentSupportsEvaluationMaximumReactorCoolantLoopPipingStressesCombinedLoadsforLoopPipingLeak-Before-BreakRCSPrimaryEquipmentSupportsStressMarginSummarySteamGeneratorUpperSupportsSeismicLoadMarginSteamGeneratorUpperSupportsSeismicLoadMarginPacaeT-1T-2T-4T-5T-6T-7T-8 LISTOFFIGURESFigure1:Figure2:Figure3:Figure4:Figure5:SteamGeneratorSnubbers-LayoutSteamGeneratorSnubbers-StructuralModificationsSteamGenerator-LayoutRigidStructuralMember(Bumper)LoopPiping/SupportSystemModelPageF-1F-2F-3F-4F-5
1.0INTRODUCTION
ThisreportdescribesaproposedmodificationtotheexistingsteamgeneratorupperlateralsupportconfigurationatGinnaStation,andtheanalyseswhichdemonstratetheacceptablilityofresultingloadsfrompostulatedseismicandotherdesignbasisevents.ExistingDesignRestrainingsupportsexistforboththeupperandlowerportionofthesteamgenerator(SG).ThelowerportionofeachSGisrestrainedlaterallyandverticallybyasetofsupportsindependentof,andnotaffectedby,theproposedmodification.Theupperportionofeachofthetwosteamgeneratorsisrestrainedagainstlateralseismicandpipebreakloadsbyeight,large(532,000.lb.capacity)hydraulicsnubbersasshowninFigure1.ThesesnubbersareconnectedbetweenthebuildingstructureandaringgirderwhichisattachedtofourlugsweldedtotheSGshell.Thesnubbersareinstalledinfourpairswithonepairapproximatelyparalleltothehotlegonthereactorsideofthesteamgenerator,andtheotherpairsplacedapproximately90'part.1.2ProgramOverviewTheintentoftheproposedupperlateralsupportmodificationistoreplacesixoftheeighthydraulicsnubbersperSGwithrigid
structuralmembers(bumpers),therebyminimizingthenumberofhydraulicsnubbersinserviceforthisapplication.TheredesignedSGuppersupportconfigurationwillretaintwohydraulicsnubbersoneachsteamgeneratorringgirder.Thesesnubbers,alongwiththerearbumpers,willrestrain.thesteamgeneratoragainstdynamicmotionsandloadingsalongtheaxisofthehot,leg.Restraintofmotionsandloadingsnormaltothehotlegwillbeprovidedbythereplacementbumpersinthatdirection.TheredesignedSGuppersupportconfigurationisshowninFigure2.Thereplacementsupporthardwareconsistsofindividualstructuralassemblieswhichwillbeinstalledwhereveranexistinghydraulicsnubberisremoved.AtypicalassemblyisshowninFigure4.Eachassemblyisstructurallyrigidundercompressionbutwillallowfreedomofmovementinthetensiledirection.EachassemblyisindividuallyadjustableinthefieldtoensurethatclearancesateachbumperpositionareadequateforRCLexpansionyetdonotexceedthosepermittedbytheRCLanalysis.Thebumperassembly,anditsindividualcomponents,willbesizedandanalyzedtowithstandthenewdesignbasisloads.DetaileddesignoftherigidstructuralmembershasbeenperformedbyRG&E.FabricationwillbeperformedbyaqualifiedsupplierhavingaQualityAssuranceProgrammeetingtherequirementsofANSIN45.2.1-2 1.3.AnticipatedBenefitsTherequiredmaintenance,in-serviceinspectionandtestingoftheexistingsnubbersareperformedduringannualrefuelingoutages.Surveillanceactivitiesareperformedperiodicallythroughouttheyear.Byreplacingselectedsnubberswithbumpers,annualmaintenanceactivitiesand,consequently,annualradiationexposurestomaintenancepersonnelcanbeminimized.Thehydraulicsnubbersreplacedwithbumperswillberefur'bished,andstoredforuseasspares.Itisexpectedthatsparepartsprocurement,aswellasutilizationofshopfacilitiesandriggingequipment,canbeoptimizedasaresultofthissnubberreplacementprogram.PrimarySystemQualificationThesteamgeneratorhydraulicsnubberreplacementprogramhasresultedinchangesintheresponseoftheprimarysystem.TheeffectofthesechangesupontheRCSequipment,pipingandpipingsupportsystemhasbeenanalyzedbyWestinghouse.AnindependentreviewbyaconsultantwithbroadexperienceinRCSsupportdesignisalsobeingperformed.Theuseofrigidstructuralmembers(bumpers)intheSGupperlateralsupportsystemwillchangethedegreeofstiffnesswithwhichtheSGsarerestrainedagainstdynamicloads.Thesenewstiffnesseshavebeencalculatedandareincludedinthereanalyses.Loadingsfrom.adesignbasispipebreak(DBPB)postulatedtooccurinanauxiliaryline(RHR,SIaccumulatororsurgeline)branchconnectionhavealsobeendevelopedusingthenewupperlateralsupportstiffnesses,to1-3 assesstheeffectofthenewSGuppersupportconfigurationonthereactorcoolantsystem.PipebreaksintheMainSteamandFeedwaterpipingatthecorrespondingSGnozzleshavealsobeenconsidered.TheanalysisresultsindicatethatRCLstressesanddeflectionshavenotchangedsignificantlyfrompreviousanalyses.ThedetailsoftheRCLpipingsystemanalysis,fortherevisedSGupperlateralsupportconfiguration,areprovidedinSection3.1ofthisreport.Theprimaryequipmentsupportswerealsore-evaluatedfornewsupportloadsgeneratedfromtherevisedRCSpipingsystemanalysisbasedontheproposedSGupperlateralsupportconfiguration;TheevaluationwasconservativelyperformedinaccordancewiththerequirementsoftheASMEBoilerandPressureVesselCode-1974Edition,subsectionNFandAppendixF.AdetaileddiscussionoftheprimaryequipmentsupportevaluationisprovidedinSection3.2ofthisreport.ResultsoftheevaluationaresummarizedinTable6.1.5IntentofReportThisreportisintendedtopresentthestructuralqualificationsfortheredesignedsteamgeneratorupperlateralsupportconfigura-tion.ItcontainsthesupportingdatatoconcludethatthemaximumstressesintheRCS,andtheprimaryequipmentsupports,arelessthantheCodeallowablevalues.
2.0DESIGNLOADSANDCRITERIA2.1DesignBasisLoads2.1.1LoadingConditionsTheSGhydraulicsnubberreplacementprogramwillassurethatadequatesupportcapacityismaintainedwithrespecttothedesignbasisloads.TheRCL,withthemodifiedsteamgeneratorupperlateralsupportconfiguration,wasanalyzedforthefollowingloadingconditions:a.Deadweightb.Internalpressurec.Thermalexpansiond.Seismicevents(OBEandSSE)e.PostulatedpiperupturesatSGsecondary-sidenozzles(llainSteam,Feedwater)f.PostulatedpiperupturesatRCLauxiliarylinenozzles(PressurizerSurge,SIAccumulator,ResidualHeatRemoval)TheloadsarecombinedinaccordancewithTables1,2and3.TheloadingconditionswereevaluatedwiththeRCSatfull-powerconditions.Thisisconsistentwithgenericanalysesofthis2-1 type,representsthehigherprobabilityevent,andoccurswhenthepipeisstressedfromdesignRCLpressures.2.1.2PostulatedPipeRupturesa~RCSPipeRupturesTheprobabilityofrupturingprimarysystempipingisextremelylowunderdesignbasisconditions.IndependentreviewofthedesignandconstructionpracticesusedinWestinghousePWRPlantsbyLawrenceLivermoreNationalLaboratory(reference2)hasprovidedassurancethattherearenodeficiencesintheWestinghouseRCLdesignorconstructionwhichwillsignificantlyaffecttheprobabilityofdouble-endedguillotinebreakintheRCL.Westinghousetopicalreport,WCAP-9558,Rev.1(reference1),providedthetechnicalbasisthatpostulateddesignbasisflawswouldnotleadtocatastrophicfailureoftheGinnastainlesssteelRCLpiping.ThisWCAPdocumentedtheplantspecificfracturemechanicsstudyindemonstratingtheleak-before-breakcapability.ThisWCAPwasreviewedbytheNRCanditsconclusionswereapprovedforapplicationtoGinnabyletterdatedSeptember9,1986(NRCapprovalofRG&EresponsetoGenericLetter84-04).Terminal-endpipebreaksarepostulatedintheRCLat.auxiliarylinebranchconnectionnozzlestotheResidualHeatRemoval{RHR)System,theSafetyInjection(SI)AccumulatorpipingandthePressurizerSurgepiping.Theterminal-endbreakattheSI2~2 accumulatorlinenozzledefinesthelimitingpipebreakdesignbasisloadsfortheSGupperlateralsupportsystemunderemergencyconditions.b.SecondarySystemPipeRupturesExistingpostulatedpipebreaklocationsinthesecondarysystemswerereviewed.Someintermediatebreaklocationshavebeeneliminatedfromconsiderationasdescribedbelow.Existingpostulatedterminal-endbreaksatMainSteamandFeedwaternozzlescontinuetobeassumed.i.MainSteamLineRupturesThepreviouscontrollingdesignloadfortheSGupperklateralsupportsystemwasanarbitraryintermediatepipebreakinthehorizontalmainsteamlinenearthetopoftheSG(SeeFigure3).NRCGenericLetter87-11,"RelaxationinArbitraryIntermediatePipeRuptureRequirements",providesguidanceforeliminationofarbitraryintermediatebieaksandwillbeappliedtothisprogram.PreviousGinnaSeismicUpgradeProgramanalyses(recentlyreviewedinNRCInspectionNo.=50-244/87-11),usingANSIB31.1criteria,havebeenrevisedasnecessarytoreflectchangesresultingfromthissnubberreplacementprogram.ConsistentwithGenericLetter87-11,theseanalyseshaveestablishedthatnointermediatepipebreaksneedtobepostulatedintheMainSteam(MS)piping.2-3 ii.FeedwaterlinePipeRupturesAterminal-endpipebreak,ispostulatedatthesteamgeneratorFeedwaterinlet,nozzleandnowdefinesthelimitingpipebreakdesignbasisloadsfortheSGupperlateralsupportsystemunderfaultedconditions.2.2GeneralCriteria-SeismicUpgradeProgramThedesigncodesandcriteriautilizedintheanalysisareconsistent,withthoseusedforRG&E'sSeismicUpgradeProgram.'IThatprogramwasinitiatedinresponsetoIEBulletins79-02,79-14,andtheSystematicEvaluationProgram(SEP).ThisprogramwasreviewedduringSEPandwasapprovedbytheNRCasdocumentedintheSEPSERsforTopicIII-6,"SeismicDesignConsiderations"andtheSEPIntegratedAssessment.NRCInspectionNo.50-244/83-18andInspectionNo.50-244/87-11providedareviewofRG&EworkperformedinresponsetoIEB's79-02and79-14.Since1979,RG&Ehasupgradedcriticalsafety-relatedpipingandsupports,resultinginthereevaluationandmodificationofvirtuallyallsupportsoriginallycoveredbytheIEB's.2-4 3.0PRIMARYSYSTEMANALYSIS3.1PipingAnalysis3.1.1MathematicalModelsTheRCLpipingmodelconsistsofmassandstiffnessrepresenta-tionsforthetwoRCLsandthereactorvessel.EachRCLincludestheprimarylooppiping,asteamgeneratorandareactorcoolantpump.Theprimaryequipment,supportsarerepresentedbystiffnessmatrices.TheanalysisoftheRCSwasperformedusingatwo-loopmodel(SeeFigure5)toobtaincomponent.andsupportloadsanddisplacements.ThismodelisidenticaltotheoneusedpreviouslyintheGinnaPipingSeismicUpgradeProgramexceptforthefollowing:a~ThenewSGupperlateralsupportdesignisrepresentedbytwostiffnessmatrices.Onematrixprovidesstiffnessalongthesnubberaxis;thesecondprovidesstiffnessperpendiculartothesnubberaxis.b.Eachexistingpinned-end,tubularsupportcolumnundertheSG'sandtheRCP'sisrepresentedbyastiffnessmatrixbasedonrevisedstiffnessvalueswhichaccountfortheembedmentofthesupportingstructuralframeinthereinforcedconcreteslab.Thisisamorerealisticrepresentationof3-1
theexistingconfigurationandeliminatestheneedfortranslationofloadsfromglobaltolocalcoordinates.3.1.2MethodologyTheseismicanalysisisperformedbytheenveloperesponsespectramethod.Peak-broadenedfloorresponsespectrafortwopercentandfourpercentcriticaldamping(OBEandSSE,respectively)wereusedinconformancewithRegulatoryGuides1.60and1.61.TheuseoffourpercentcriticaldampingforSSEwasdevelopedandjustifiedbylow-displacementtesting.ThetestingprogramsaredescribedinWCAP-7921,whichhasbeenacceptedbytheNRC(reference9).ThemodificationintheSGupperlateralsupportswillnotaffecttheconclus'ionofthedampingtestingprogram.ResponsestothethreedirectionsofearthquakeloadingwereevaluatedinaccordancewiththeGinnaPipingSeismicUpgradeProgrambycombiningallthreedirectionalearthquakesbythesquare-root-sum-of-the-squares(SRSS)method.TheWestinghouseepsilon-methodofcloselyspacedmodescombinationwasusedintheanalysis.ThecombinationequationsarepresentedinAppendixA.ThismethodofcombinationofmodalresponsesandspatialcomponentsisconsistentwiththeNRCguidelinesinRegulatoryGuide1.92.ThismethodhasbeenusedonnumerousotherWestinghousePWR's(suchasVogtleandSouthTexas)asdiscussedintheirrespectiveFSAR's.TheNRChasapprovedtheuseofthismethodviatheSER'sassociatedwithmodalresponsecombinationonthoseWestinghouseplants.3-2 Time-historyforcingfunctionsforthePressurizerSurge,RHRandSIaccumulatornozzlebreakswereappliedtotheRCLanalyticalmodeltoobtainthecorrespondingtransientloads.TheblowdownfluidthrustforcingfunctionsatthebreaklocationsassociatedwiththeseRCLauxiliarylinenozzlebreaksaretime-historyforcesinthex,yandzdirections.TheyareappliedtotheRCLanalyticalmodelat,thelumped-masspointwhereeachauxiliarylinejoinstheRCL.Jetimpingementloadsgeneratedbytheblow-downoftheseveredauxiliarylineswerealsoappliedatthelumpedmasspointwheretheauxiliarylinejoinstheRCL.Thetime-historyinternalfluidsystemloadsintheprimarylooppipingarealsoappliedtotheRCLanalyticalmodel.Theseloads'epresentthetravelingdecompressionblowdownwavesandarecalculatedateachRCLlocationwithachangeindirectionorchangeinflowarea.PipebreakspostulatedtooccuronthesecondarysideofthesteamgeneratorattheMainSteamoutletnozzleandat,theFeed-waterinletnozzlearemodeledasstep-functionforces.Thecalculationoftheseforcesisbasedonasimplifiedthrustcoefficient,Ct,multipliedbytheinitialpressureforce,P,A(orientedalongtheaxialnozzlecenterline).Thrustcoefficientsof1.26and2.0(1.0forthrustplus1.0forjetimpingement)wereusedforbreaksintheMainSteamandFeedwaterlines,respectively.3-3
'I 3.1.3ComputerProgramsPipinganalysesareperformedonthe"WESTDYN"Westinghousecomputerprogram(reference5).WESTDYNperforms3-dimensional,linear,elasticanalysesofpipingsystemssubjectedtointernalpressureandother-loadings(staticanddynamic).TheprogramiscapableofcombiningloadsinaccordancewiththeapplicablecodeclassofeitherASMESectionIIIorANSIB31.1.Separatecomputerrunsanalyzeeachloadingcondition(deadweight,thermal,sustainedloads,occasionalloads,pipebreakandseismic).Theprimaryoutput,fromWESTDYNdisplaysinformationabouteachanalysisperformed,includingforces,moments,anddisplacementsateachpoint.TheWESTDYNcomputercodehasbeenutilizedonnumerousWestinghouseplantsandwasreviewedandapprovedbytheNRCin1981(reference8).ThecodeisverifiedforthisapplicationandacontrolledversionismaintainedbyWestinghouse.3.1.4SupportStiffnessesToaccuratelyrepresenttheequipmentsupportsinthepipinganalyses,themodifiedsupportsystemstiffnesscharacteristicsweredevelopedforinputtothepipinganalysiscomputermodel.IndividualspringconstantsprovidedinthelocaldirectionsofrestraintweredevelopedforthemodifiedSGupperlateralsupportconfigurationandtheotherRCLprimaryequipmentsupports.Thestiffnesscalculationsconsideredthestiffnesscharacteristicsofallstructuralelementsintheloadpathincludingthesupporting concrete,structuralmembers,aswellasthetensionandcompressionstiffnessesoftheremaininghydraulicsnubbers.Duringaseismiceventloadsmayshift,betweenthesnubbersandthebumperalongtheaxisofthehot.leg.Thisshiftingisboundedintheanalysisbyutilizingthreevaluesoftheuppersupportstiffness(Kmin,KmaxandKavg)inthreeseparateanalyses.Thebumperisstifferthanthesnubber.Thus,thelowerboundvalueis,Case1,KgZNKS~BER(compression).Theupperboundvalueis,Case2,~=K~<R(compression)+KS~B<R(tension).K>Nistheactualstiffnesswhenthesteamgeneratormovestowardthereactorvessel.~istheactualstiffnesswhenthesteamgeneratormovesawayfromthereactorvessel.Finally,athirdvalueofKA>G=1/2(K>N+~)wasusedtoprovidedataonanintermediatestiffness.SeveralevaluationswereperformedusingCase1andCase2stiff-nesses,andtheworstloadsoneachindividualbumperweredeter-mined.TheresultsaresummarizedinTable8alongwithcorres-pondingloadsbasedon%heaveragestiffnessvalue,KA>G.UseofboundingstiffnessvaluesproducesadecreaseintheseismicstressmarginateachlocationascomparedwithKA>G.Adequateseismicstressmargin.stillexistssincethelowestmargin,usingtheboundingstiffness,is1.73(SG1Bsnubbers).Basedonthesechangesinseismicmargin,andthecalculatedmarginsforlooppiping(showninTable4)andotherprimary3-5 1
equipmentsupports(showninTable6),itisconcludedthatadequateseismicmarginsexistfortheredesignedSGupperlateralsupports.ThedatainTables4,5,6and7arebasedontheKA>GvalueofSGuppersupportstiffness.3.1.5PipingEvaluationCriteriaThepipingevaluationcriteriaarebasedonANSIB31.1-1973edition.TheoriginaldesignbasisoftheseismicCategoryIpipingatGinnawasinaccordancewiththe1955and1967editionsofUSASB31.1.WhenUSASB31.1wasupdatedtotheANSIB31.1,thestressanalysisformulaeandstressintensificationfactorswererevised.TheprimarystressequationsintheinitialB31.1-1973editionweresimilartothosegivenintheASMESectionIIICodeofthattime.ThestressintensificationfactorsgiveninthisversionofB31.1wereexpandedtoincludemorefittings.InusingANSIB31.1,thePipingSeismicUpgradeProgramupdatedtheanalysistoreflectASMESectionIIIconceptswhilestillretainingthephilosophyofB31.1.However,thestressintensificationfactorforbuttandsocketweldsoftheoriginaleditionofB31.1havebeenusedbecauseoflackoforiginalweldconfigurationinformation.3.1.6PipingLoadCombinationsThepipingwasevaluatedfortheloadcombinationdefinedinTable1.3-6
3.2PrimaryEquipmentSupportsEvaluation3.2.1MethodologyThesteamgeneratorupperlateralsupportsystemhasbeenredesignedbyreplacingsixoftheeightsteamgeneratorsnubbersineachloop.TherevisedconfigurationisshowninFigure2.TheRCLanalysismodelwasrevisedtoreflectthenewsupportconfigurations.Computeranalyseswereperformed,asdescribedin-Section3.1,togeneratenewRCLloadsontheprimaryequipmentsupportsystemandtheprimaryequipmentsupportswereevaluatedforthesenewloads.Theevaluationwasperformedforsupportsassociatedwiththereactorvessel,steamgeneratorsandreactorcoolantpumps.Inappropriatecases,finiteelementmodelsofsupports,viatheSTRUDLprogram,wereutilizedtoassistintheevaluation.Thesupportswererequalifiedfortherequiredcombinationsofpressure,thermal,deadweight,seismicandapplicablepiperuptureloads.3.2.2SupportLoadingsandLoadCombinationsTheloadsusedintheanalysesandrequalificationoftheequipmentsupportstructuresaredefinedinTable2.TheseloadswerecombinedfortheplantasidentifiedinTable3.Thecorrespondingloadcombinationsandtheallowableservicestresslimitsarealsoprovidedinthat,table.
r3.2.3EvaluationCriteriaTherigidstructuralmembers(bumpers)intheSGupperlateralsupportsystemaredesignedtotherequirementsofthecurrenteditionoftheoriginaldesigncode(AmericanInstituteofSteelConstruction,AISCManual,8thEdition).However,toevaluatetheequipmentsupportsfornormal,upset,emergencyandfaultedconditions,theprovisionsofASMEBoilerandPressureVesselCodeSectionIII,SubsectionNFandAppendixFwereused-1974Edition.TheASMEB&PVCodeSectionIII,SubsectionNFwasusedtoestablishallowablestresscriteriafortheequipmentsupportevaluationinlieuoftheAISCCodebecauseSubsectionNFandAppendixFcoupledwithUSNRCRegulationGuide1.124establishamoreconsistentandconservativesetofcriteria.Forexample,SubsectionNFwasdevelopedspecificallytoaddresscomponentsupportswhereastheAISCgenerallyaddressbuildingstructures.Additionally,theuseofSubsectionNF,AppendixF,andRG.1.124requiretheuseofmaterialpropertiesatservicetemperature,limitbucklingto0.67criticalbuckling,andestablishupperboundallowablesontensionandshearstress.Theevaluationwasperformedbyhandcalculations,andbycomputeranalysiswhereappropriate.3.2.4ComputerProgramsTheprimaryequipmentsupportswereevaluatedbyhandcalculationsand,whereappropriate,byfiniteelementelementcomputeranalysis3-8 using"STRUDL."STRUDL,partoftheICEScivilengineeringcomputersystem,iswidelyusedfortheanalysisanddesignofstructures.Itisapplicabletolinearelastictwo-andthree-dimensionalframeortrussstructures,employsthestiffnessformulation,andisvalidonlyforsmalldisplacements.Structuregeometry,topology,andelementorientationandcross-sectionpropertiesaredescribedinfreeformat.Memberandsupportjointreleases,suchaspinandrollers,arespecified.Otherwise,'ixrestraintcomponentsareassumedateachendofeachmemberandateachsupportjoint.Printedoutputcontent,specifiedbyinputcommands,includesmemberforcesanddistortions,jointdisplacements,supportjointreactions,andmemberstresses.TheSTRUDLcomputercodehasbeenutilizedonnumerousWestinghouse'plantsandwasreviewedandapprovedbytheNRCin1981(reference8).ThecodeisverifiedforthisapplicationandacontrolledversionismaintainedbyWestinghouse.3-9 4.0EVALUATIONANDRESULTS4.1ReactorCoolant,LoopPipingTable4providesthelevelofstressintheRCLpipingandtheallowablestressesfromtheDesignCode(reference4).Theresultsshowthatthestressesinthepipingarewithinallowablelimits.AcomparisonbetweenthemaximumstressintheRCLIpipingforthecurrentandredesignedsupportconfigurationshowsthatthereareonlyverysmallchangesinthecalculatedstresses.4.2ApplicationofLeak-Before-BreakWiththeredesignedsteamgeneratorupperlateralsupportconfigur-ation,revisedloads(forcesandmoments)intheRCLpipinghavebeengenerated.TherevisedloadsarecomparedwiththoseloadsinGenericLetter84-04(reference7)inTable5.Thecalculatedaxialstress(19.42ksi)is60%oftheallowableaxialstress(32.4ksi).Basedonthecomparison,itisverifiedthattheleak-before-breakconclusionsofWCAP-9558Rev.1remainvalidfortheredesignedsupportconfiguration.4.3MainSteamLineBreakLocationsTheterminal-endbreakinthemainsteamlinepipingatthesteamgeneratornozzleisadesignbasispipebreak.Themaximumcalculatedstressintensityatintermediatelocationsforcombinedpressure,deadweight,thermalandOBEloadingsis27.1ksi.This4-1 islessthanthethresholdstressintensityof0.8(1.2Sh+S)or29.6ksi.Therefore,therearenohigh-stressintermediatebreaklocationsinthemainsteamlinesinsidecontainment.4.4PrimaryEquipmentSupportsThestressmarginsforRCLequipmentsupportsresultingfromtheRCLanalysisconsideringtheredesignedsteamgeneratorupperlateralsupportconfigurationsaresummarizedinTable6forallloadingcombinations.Thestressmarginisdefinedastheratiooftheallowablesupportstresstotheactualsupportstress.Loadingevaluationsperformedwiththeredesignedsupportconfigura-tiondemonstratethatallRCLequipmentsupportstressessatisfystresslimitswithanadequatemarginofsafety.Seismicmarginisassessedbythestressmarginfortheloadcombination,(DW+TN+SSE).ThesestressmarginsaresummarizedinTable7fortheexistingandredesignedsteamgeneratorupperlateralsupportconfiguration.Theresultsdemonstratethatasignificantmarginofsafetyexistsfortheredesignedsteamgeneratorupperlateralsupport.4.5PrimaryComponentNozzleLoadConformanceTheRCLpipingloadsontheprimarynozzlesofthereactorvessel,thesteamgenerators,andthereactorcoolantpumpswereevaluated.Theconformanceevaluationconsistedofloadcomponent.comparisons,andloadcombinationcomparisons,inaccordancewitheachoftherespectiveEquipmentSpecificationsorwithapplicablenozzle4-2 allowablelimits.ItwasconcludedthatallRCLpipingloadsactingontheprimarycomponentnozzleswereacceptable.4.6EvaluationofAuxiliaryLinesTheRCLpipingandprimaryequipment,displacementswerecomparedtothecorrespondingdisplacementsusedinthepreviousanalyses.Theyarefoundtobelessthanthepreviousanalysisresultsorwithini1/16inch.Duetotheflexibilityoftheattachedpipingsystems(designedtobeinherentlyflexibletoaccommodatethermalgrowthoftheRCS)andthegapswhichexistbetweenthepipeandthesupportingstructure,anincreaseinanchormotionsattheloopconnectionpointofupto1/16inchwillnotcausesignificantchangesinpipingstress.Therefore,auxiliarypipingsystemsattachedtotheRCLarenotaffectedbytheredesignedsteamgeneratoruppersupportconfiguration.4.7BuildingStructuralEvaluation4.7.1EvaluationofLocalAreasCorbelsandembedmentswereevaluatedfortensionloadsandtheircapacitywasfoundtoexceedthatofthehydraulicsnubbers.Corbelswerealsoevaluatedfortherigidstrutbearingloads,andwerefoundtobeloadedtonomorethan60%ofallowable.
AllevaluationswereperformedwithrespecttoACI-349,andAppendixBofACI-349.4.7.2SecondaryShieldWallsBumperelevationsarethesameastheReactorBuildingOperatingFloor.Thereisnolocalizedbending,sincethefloorslabactsasastiffeningring.Resultingtensilestressesarelow,withamaximumofabout,40%ofallowable.AllevaluationsweredonewithrespecttoACI-349.4.7.3ConclusionInconclusion,theexistingcontainmentbuildingstructuresareadequateforthenewdesignbasisloadsassociatedwiththenewsnubber/bumperSGupperlateralsupportconfiguration.
5.0ADDITIONALCONSIDERATIONSI5.1OvertemperatureEventsThedesignbasisovertemperatureeventistheloss-of-loadtransient.RCI,equipmentsupportstressmarginsforthistransientareadequateasshowninTable6.Anevaluationhasalsobeenperformedfortheovertemperatureconditionsfollowingafeedwaterlinepipebreak.Themaximumloadonanyindividualbumperwasfoundtobe23.4kips.Thisissignificantlylessthanthe820kipsmaximumcapacityofeachbumper.ThecorrespondingRCZpipingstresseswerealsofoundtobemuchlessthanthecode-allowablethermalstress.5-1 6.0QUALITYASSURANCE6.1RochesterGas&ElectricCorporationTheoverallprojectisbeingconductedundertheRG&EQualityAssuranceProgram.Thereplacementrigidstructuralmembers{bumpers)willbefabricatedbyasupplierhavingaQualityAssuranceProgrammeetingtherequirementsofANSIN45.2.RG&Ehasspecifiedmaterialtraceability,welderqualification,non-destructiveexaminationandotherrequirementsinthepurchaseorder.6.2WestinghouseElectricCorporationThestructuralqualificationworkperformedbyWestinghousehasbeenindependentlyreviewedatWestinghouseasasafety-relatedcalculationandmeets10CFR50,AppendixB,QualityAssurancerequirements.ThedetailedresultsoftheanalysesaremaintainedinWestinghouseCentralFilesinaccordancewithWestinghouseQualityAssuranceprocedures(ref.10and11).6.3AltranCorporationAnindependent,thirdpartyreviewisbeingperformedbyAltranCorporationandDr.ThomasC.Esselman.Dr.Esselmanandhisassociateswillconductathoroughreviewoftheassumptions,designbases,analysesandotherdesigndocumentsproducedbyWestinghouse.6-1
7.0CONCLUSION
SBasedontheresultsofloadingevaluationsofthereactorcoolantsystemwiththeredesignedSGupperlateralsupportconfigurationthefollowingconclusionsaremade:a.Thecombinationofhydraulicsnubbersandrigidstructuralmembers(bumpers)whichcomprisetherevisedsteamgeneratorupperlateralsupportsystemmaintainadequaterestraintofeachsteamgeneratorunderthedesignbasisloads.b.ThemaximumstressesintheRCSpipingandprimaryequipmentsupportsarewithinCodeallowables.,c.ThemaximumdisplacementsintheRCSpipinghavebeenaccountedforinanalysesofauxiliarypipingsystemsattachedtotheRCS,anddonotsignificantlyaffectthoseanalyses.d.Thereactorcoolantlooppipingandequipmentsupportscontinuetohaveacceptablemarginsofsafetyforalldesignbasisevents.e.TheContainmentBuildingstructuresareadequatetocarrytheloadsimposedbythenewsnubber/bumperSGupperlateralsupportconfiguration.7-1
8.0REFERENCES
1.WCAP-9558,Rev.1,MechanisticFractureEv'aluationofReactorCoolantPipeContainingAPostulatedCircumferentialThrough-WallCrackJune1980.2.NUREG/CR-3660,UCID-19988,Volume3,February,1985,"ProbabilityofPipeFailureinReactorCoolantLoopsofWestinghousePWRPlants,"Volume3,"GuillotineBreakIndirectlyInducedbyEarthquakes,"LawrenceLivermoreNationalLaboratory.3.ASMEBoilerandPressureVesselCode,SectionIII,SubsectionNFandAppendixF,AmericanSocietyofMechanicalEngineers,1974Edition(forSupportsEvalution).4.ANSIB31.1PowerPipingCode1967Edition,includingSummer1973Addenda.5."PipingAnalysisComputerCodesManualII"WestinghouseProprietaryClass3,WestinghouseElectricCorporation,Pittsburgh,PA.6.NRCBranchTechnicalPositionMEB3-1,Rev.2,1987PostulatedRuptureLocationsinFluidSystemPiping'InsideandOutsideContainment(GenericLetter87-11)8-1 7.NRCGenericLetter84-04,2/1/84.8.NRCapprovalletterforWCAP-8252(WESTDYN),LetterfromR.L.Tedesco,NRC,toT.M.Anderson,Westinghouse,dated4/7/81.9.WCAP7921-AR,May1974,"DampingValuesofNuclearPlantComponents."10.WestinghousePowerSystemBusinessUnitQualityAssuranceProgramforBasicComponentsManual,WCAP-9550,Rev.16,June30,1987.ll.WestinghouseNTSD/GTSDQualityAssuranceProgramManualforNuclearBasicComponents,WCAP-9565,Rev.11,Aug.31,1987.8-2 Table1RCSPIPINGLOADCOMBINATIONSANDSTRESSLIMITSConditionNormalUpsetEmergencyFaultedMax.ThermalLoadinCombinationDesignPressure+DeadweightDesignPressure+Deadweight,+OBEDesignPressure+Deadweight+SSEDesignPressure+Deadweight+(SSE+DBA)**Max.ThermalStressRange***+OBEDisplacementANSIB31.1Eationsll12121213NormalSMax.ThermalDesignPressure+Deadweight+Max.14ThermalStressRange+OBEDisplacements**SRSScombinationofSSEandDBAloads***Loss-of-loadovertemperaturetransientconditionThepipingstressequationsare:PD+.75iA4tZ<1.0ShEquation(11)PD+.75i4tMA+MZ.1.2Sh(Upset)Equation(12)<1.8Sh(Emergency)2.4Sh(Faulted)iCZPD+.75iM~+iC~M4tZZ<Sa<S+SEquation(13)Equation(14)Where:MA=Resultantmomentduetodeadloadandothersustainedloads.MCDResultantmomentduetooccasionalloads.Resultantmomentduetorangeofthermalexpansionloadings.InternalDesignPressure.Outsidediameterofpipe.Nominalwallthicknessofpipe.SectionmodulusMaterialallowablestressatmaximumtemperature.SaAllowablestressrangeforexpansionstress.NStressIntensificationFactor.T-1
,C TABLE2DEFINITIONOFLOADINGCONDITIONSFORPRIMARYEQUIPMENTSUPPORTSEVALUATIONLoadinCondition1.SustainedLoadsAbbreviationsDW,Deadweight+P,OperatingPressure+TN,NormalOperatingThermal2.3.5.6.7.Transientsa.Over-temperatureTransientOperatingBasisEarthquakeSafeShutdownEarthguakeDesignBasisPipeBreaka.ResidualHeatRemovalLineb.AccumulatorZinec.PressurizerSurgeLineMainSteamLineBreakFeedWaterPipeBreakSOT,SystemOperatingTransientTAOBESSEDBPBRHRACCSURGMS TABLE3LOADCOMBINATIONSANDALLOWABLESTRESSLIMITSFORPRIMARYEQUIPMENTSUPPORTSEVALUATIONPlantEventSystemOperatingConditionsServiceLoadingCombinationsServiceLevelStressLimits1.NormalOperation2.Plant/SystemOperatingTransients(SOT)+OBE3.DBPB4.SSE5.DBPB(orMS/FWPB)+SSENote:NormalUpsetEmergencyFaultedFaultedSustainedLoadsSustainedLoads+SOT+OBEBSustainedLoads+DBPBCSustainedLoads+SSEDSustainedLoads+(DBPBorDMS/FWPB)+SSE1.ThepipebreakloadsandSSEloadsarecombinedbythesquare-root-sum-of-the-squaresmethod.2.StresslevelsasdefinedbyASMEB&PVCodeSectionIII,SubsectionNF,1974Edition.
TABLE4MAXINMREACTORCOOLANTLOOPPIPINGSTRESSES(BasedonKAVG)CurrentANSI(1)ConfigurationB31.1CodeRCLStressE~natinn(2)~Piin(ksi)RedesignedConfigurationStress(ksi)ANSIB31.1CodeAllow-ableStress"(ksi)PercentageofAllowableHLXLCL(12)DesignHLandUpsetXLCL7.26~96.99.89.810.07.26.96.98.08.99.416.816.816.820.120.120.14N41$41/40$41$4Q,(12)Emergency(i2)(Faulted)(i3)SeeNote3{i4)NOTES:HLXLCLHLXLCLHLXLCLHLXLCL11.712.112.59.75.37.416'11.113.18.610.611.519.711.517.89.75.37.416.811.113.130.230.230'40.340.340.327.527.527.544.444.444.429K35K38$49/29K45$36$20/27/38~25'X35%%d(1)HL-HotLeg,XL-Crossoverleg,CL-ColdlegPiperuptureloadswerenotconsidered.Nofaultedstresseswerecalculatedforcurrentdesign.(2)LoadcombinationsareshowninTablel.a(3)Loss-of-loadovertemperaturetransienteffectsareincluded.
TABLE5COMBINEDLOADSFORLOOPPIPINGLEAK-BEFORE-BREAK(BasedonKAVGLoadCombinationAxialForcekisBendingMomentin-kisCombinedAxialStressksiNormalSSE1939251Normal+SSE21901676028201958016.88(calculated)2.54(calculated)19.42(calculated)1800Normal+SSE45600(2)32.4(allowable){SeeNote2)Notes:{1)AllowablebasedonWCAP-9558,Rev.l.(2)Umbrellabendingmoment,inNRCGenericLetter84-04is42,000in-kips.
TABLE6RCSPRIMARYEQUIPMENTSUPPORTSSTRESSMARGINSUMMARY(StressMargin=Allowable/Actual)(BasedonKAVG)ServiceLevelNormalUpsetEmergencySSEFaultedLoadCombinationDW+TNDW+TA+OBEDW+TN+DBPBDW+TN+SSEDW+Q+[(SSE+PIBK)]SGUpperSupportsBumpersSeeNote3SnubbersSeeNote32.533.173.24(ACC)2.416.26(ACC)2.251.79(FW)1.11(FW)SGLowerSupportsLateralSeeNote31.67Columns3.511.651.57(SURG)1.773.11(ACC)3.291.21(SURG)2.19(MS)ReactorCoolantPumpsLateralSeeNote3Columns.5.154.551.8718.12(ACC)8.102.76(ACC)1.877.46(ACC)1.87(ACC)ReactorVesselLateralSeeNote3Vertical3.054.331.291.31(ACC)5.942.09(ACC)4.531.41(ACC)3.45(ACC)Notes:1)TheloadsymbolsaredefinedinTable2.2)PIBKincludesDBPBandMS/FWbreaks3)Undernormalconditionsnosignificantloadsareimposedontheselateralsupportelements.
TABLE7STEAMGENERATORUPPERSUPPORTSSEISMICLOADMARGINS(BasedonKAVG)LOOPNO.lABUMPERIDSN"1123SEISMICLOADS(DW+TN+SSE)(kips)EXISTINGREDESIGNEDSGUS(1)SGUS582'410.4582.0335.4582.6410.5582.6410.5SGUSCAPACITY(Kips)10641640164016401064106410641064"30-42-30"30/CHANGEEXISTINGREDESIGNED1.831.831.831.832.594.893.993.99SEISMICLOADMARGIN(Allowable/Actual)EXISTINGREDESIGNED1BSN-24567514.2470.0448.0312.2287.2472.3453.3386.5309.9340.0-8-4-14-1+18.41064106410645325321064164016408208202.072.262.371.701'52.253.614.242.642.41(1)SeeNoteAttached.
NOTETOTABLE7Theoriginalseismicsupportloadcalculationsincludedanadditionalcontributionwhichisnotrequiredintherevisedsupportloadcalculations.Intheoriginalcase,thetotalseismicsupport~planeloadattheuppersupportwasfirstcalculatedbydynamicanalysisinglobalcoordinatesandthenrotatedtothelocalcoordinatesofthesupportmembers.Intherevisedcase,theindividualsupportmembersweremodeleddirectlyinthedynamicmodelsothatarotationfromsupportplaneloadstomemberloadswerenotrequired.Therotationofcoordinatesmustbedoneconservatively,sincetherearenosignsassociatedwiththetotalseismicforcecomponentsinglobalcoordinates.Therefore,theoriginaldesignloadsaremoreconservativelycalculatedthanthereviseddesignloads.
TABLE8STEAMGENERATORUPPERSUPPORTSSEISMICLOADMARGINS(UsingKandK/K.)avgmaxminSEISMICLOADS(DW+TN+SSE)(kips)SGUSCAPACITY(Kips)SEISMICLOADMARGIN(Allowable/Actual)LOOPNO.BUMPERID~KavKmax/Kmin$CHANGEREDESIGNEDK~avKmax/KminlASN-1123410.4335.4410.5410.5533.5436.0533.7533.7+30+30+30+3010641640164016402.594.893.993.991.993.763.073.071BSN-245-67472.3453=3386.5309.9340.0614.0589.3502.5402.9442.0+3Q+30+30+3Q+301064164016408208202.253.614.242.642.41-1.732.783.262.031.86 APPENDIXACOMBINATIONOFSEISMICMODALRESPONSESForSeismicCategoryIcomponentswithintheNSSSscope,themethodusedtocombinemodalresponsesisdescribedbelow.Thetotalunidirec-tionalseismicresponseforNSSSequipmentisobtainedbycombiningtheindividualmodalresponsesusingtheSRSSmethod.Forsystemshavingmodeswithcloselyspacedfr'equencies,thismethodismodifiedtoincludethepossibleeffectofthesemodes.Thegroupsofcloselyspacedmodesarechosensuchthatthedifferencebetweenthefrequenciesofthefirst,modeandthelastmodeinthegroupdoesnotexceed10percentofthelowerfrequency.CombinedtotalresponseforsystemswhichhavesuchcloselyspacedmodalfrequenciesisobtainedbyaddingtotheSRSSofallmodestheproductoftheresponsesofthemodesineachgroupofcloselyspacedmodesandacouplingfactor,c.Thiscanberepresentedmathematicallyas:NSNj-1NjRi+2ZZZRkR~ok(EquationA-1)i=1'=1k=MjK=k+1where:R=TotalunidirectionalresponseR.=AbsolutevalueofresponseofmodeiiN=Totalnumberof.modesconsideredS=NumberofgroupsofcloselyspacedmodesMj=Lowestmodalnumberassociatedwith"groupjofcloselyspacedmodesN.=Highestmodalnumberassociatedwithgroupjofcloselyspacedmodesckt=Couplingfactordefinedasfollows:kkkand, where:e=FrequencyofcloselyspacedmodeKpk=FractionofcriticaldampingincloselyspacedmodeKtd=DurationoftheearthquakeForexample,assumethatthepredominantcontributingmodeshavefrequenciesasgivenbelow:Mode12345678Frequency5.08.08.38.611.015.516.020Therearetwogroupsofcloselyspacedmodes,namelymodes2,3,4and6,7.Therefore:IS=2,NumberofgroupsofcloselyspacedmodesM=2,Lowestmodalnumber"associatedwithgroup11N=4,Highest,modalnumberassociatedwithgroup11M=6,Lowestmodalnumberassociatedwithgroup22N=7,Highestmodalnumberassociatedwithgroup22N=8,TotalnumberofmodesconsideredThetotalresponseforthissystemis,asderivedfromtheexpansionofEquationA-1:[R+R+R+....+R81+2R2R3~23+2R2R4~2422222123+2R3R4c34+2R6R7867ThefirstterminbracketsrepresentstheSRSSsummationofeachoftheeightexamplemodes.Thenextthreetermsaccountfortheadditionaleffectsduetointeractionbetweenexamplemodes2,3and4.Thefinaltermsimilarlyaccountsforinteractioneffectsbetweenexamplemodes6and7.A-2
<4'1I~gV~~'-~it4~+-IMI-.<~,,.IgiQPo~~~Wal~L<~AI.)Qfl~~aa~,Mri+i~i5l-~~r~Ifr PLAN8ELEVATION227'-9>)4"EXiST(HGBUILT-UPSTRUCTURALRINGGIRDER(REF::6'N6'P.52I-050)g.GAC<dtCAVLlYSG)Agv.SG1BthlFMl5T<tlGTVRALCiUIQE.S(TyPiCAL-P0tqg/C'S)QI3UMP6RLOCA'ftOA22~P.M>~532KIPCAPACITYHYDRAULICSNUBBERE'<<~~<<@(ANKER-HOLTH)(2pea5/c)<0-<</ttlgc.+8-I-8G4'-lS87Fi6.lJ@E2.l"INN'TeAMCEMERATORsNUSVMs-sTmcTUa4LMoÃric<Tiow MA.le@STBAnASTCAVOUTLCTIIOZZI.CQOISTUACSCPASATO1ilAIIWAT~IIOAQAlWATC1LCVCI.SCCOWATC1IIIOCTSNIIII.VAIICIIOISTU15SCSASAT01~~FicOUPAfCRQIAZC,ANTIVISSATIOII~A15LIFAuafRuuAZCOuS(z)TUSESUPPORTS~ActoRQoQLAQTHohgt.t-t.oM%R.SUPPoRTj3RAcKE7s(4)PlLIIIIIAV(2)STEAMGENERATORjA,/)EI(~~p>c.r~g b~CL~+ToPHUTlil)IIInI0+~5Cbd,~p'4'6>IP8SHRF7fvfoUhlgigl5R&<YS1{swing>ec)g8'IQfoRc.6gCow~Cg6~pggav)Nnu,(s~s-cgF'l&UR84hhOU~INGPga,cVE'f(Fj41Sprig)(T+vicA<pt.AAviE,tu)
SG233223SGUpperSupportRCP219SG133277273269263RCPSupport259242131203400RV1294289VesselSupports24922209SGLowSupport253Loop18283101500194103189109North123Loop1A119SGLowerSupportSGUpperSupportRCP143149159177173169163RCPSupport153FIGURE$!RGEGINNAREACTORCOOLANTLOOPSlAklBANALYTICALMODEL(SEISHICANDSTATIC)JGMIo-I<-&7 gP