ML17256A402

Analysis of Plant Response During 820125 Steam Generator Tube Failure at Re Ginna Nuclear Power Plant.

ML17256A402
Person / Time
Site:	Ginna
Issue date:	11/22/1982
From:	VOLPENHEIN E C WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP.
To:
Shared Package
ML17256A400	List: ML17256A399 ML17256A401 ML17256A402 ML17256A403 ML17256A404 ML17256A405
References
3274Q:1-111782, NUDOCS 8211290429
Download: ML17256A402 (91)

Text

ATTACHMENTAANALYSISOFPOTENTIALENVIRONMENTALCONSEQUENCESFOLLOWINGASTEAMGENERATORTUBEFAILUREATR.E.GINNANUCLEARPOWERPLANTNOVEMBER1982Preparedby:K.RubinE.VolpenheinWestinghouseElectricCorporationNuclearEnergySystemsP;0.Box355Pittsburgh,Pennsylvania15230Preparedfor:RochesterGasandElectric89EastAvenueRochester,NewYork14649ggffg+O4PP821122PDRADOCK05000244PPDR TABLEOFCONTENTSSectionPageABSTRACT~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~1LISTOFTABLESLISTOFFIGURES....................~....,..ivI.INTRODUCTION.....~1II.MASSRELEASESII.lDesignBasisAccident.II.l.lSequenceof,EventsII.1.2MethodofAnalysisII.2GinnaEvent.~~~2~~~2~~~2~~~510III.ENVIRONMENTALCONSEQUENCESANALYSISIII.lDesignBasisAccidentIII.2GinnaEventAnalysis.~~~~~~~27~~~~~~027~~~~~~o4DIV.SUMMARYANDCONCLUSIONS~~~~~~o56'REFERENCESi~~~~~~~~57 ABSTRACTThepotentialradiologicalconsequencesofasteamgeneratortubefailureeventwereevaluatedfortheR.E.Ginnanuclearpowerplanttodemonstratethatstandardlimitationsoninitialcoolantactivityareacceptable.Massreleasesfollowingadesignbasistuberupturewerecalculatedforboth30minuteand60minuteoperatorresponsetimes.Thesiteboundaryandlowpopulationzoneexposureswereconservativelycalculatedforthesereleases.'naddition,thestandardtechnicalspecificationlimitoninitialcoolantactivityandrealisticmeteorologywereappliedto"bestestimate"mass"releaseduringtheJanuary25,1982tubefailureeventatGinna.Resultsshowthattheconservativeassessmentoftheenvironmentalconsequencesarewithinacceptablelimitsandthatthepotentialexposurefromamorerealisticeventisminimal.

LISTOFTABLESTABLEII.1.2-1DESIGNBASISACCIDENTSEQUENCEOFEVENTSTABLEII.1.2-2.MASSRELEASESDURINGADESIGNBASISSGTR:30MINUTERECOVERYTABLEII.1.2-3MASSRELEASESDURINGADfSIGNBASISSGTR:60MINUTfRECOVERYTABLEII.2-1TABLEII.2-2GINNASEQUENCEOFEVENTSBESTESTIMATEMASSRELEASESDURINGGINNASGTREVENTTABLEIII.1-1PARAMETERSUSEDINEVALUATINGTHERADIOLOGICALCONSEQUENCESOFASTEAMGENERATORTUBERUPTURETABLEIII.1-2IODINEAPPEARANCfRATESINTHEREACTORCOOLANTFORA,DESIGNBASISSGTRTABLEIII.1-3REACTORCOOLANTIODINEANDNOBLEGASACTIVITYTABLEIII.1-4SHORT-TERNATMOSPHEREDISPERSIONFACTORSANDBREATHINGRATESFORACCIDENTANALYSISTABLEIII.1-5ISOTOPICDATATABLEIII.1-6RESULTSOFDESIGNBASISANALYSISTABLfIII.2-1PARAMETERSUSEDINEVALUATINGTHERADIOLOGICALCONSEQUENCESOFTHfGINNAEVENTTABLEIII.2-2IODINEAPPEARANCERATESINTHEREACTORCOOLANT LISTOFTABLES(Continued)TABLEIII.2-3SHORT-TERMATMOSPHERICDISPERSIONFACTORSANDBREATHINGRATESFORACCIDENTANALYSISTABLEIII.2-4RESULTSOFGINNAEVENTANALYSIS111 LISTOFFIGURESFIGUREII.1.2-1FAULTEDSTEAMGENERATORWATERVOLUME~~FIGUREII.1.2-2REACTORCOOLANTSYSTEMPRESSUREFIGUREII.1.2-3FAULTEDSTEAMGENERATORPRESSUREFIGUREII.l.2-4REACTORCOOLANTAVERAGETEMPERATUREFIGUREII.1.2-5PRESSURIZERWATERVOLUMEFIGUREII.1.2-6FAULTEDSTEAMGENERATORSTEAMFLOWFIGUREII.l.2-7PRIMARY-TO-SECONDARYLEAKAGEFIGUREII.1.2-8BREAKFLOWFLASHINGFRACTIONFIGUREII.2-1CALCULATEDFAULTEDSTEAMGENERATORWATERVOLUMEDURINGTHEGINNAEVENTFIGUREII.2-2REACTORCOOLANTSYSTEMPRESSUREDURINGTHEGINNAEVENTFIGUREII.2-3FAULTEDSTEAMGENERATORPRESSUREDURINGTHEGINNAEVENTFIGUREII.2-4CALCULATEDBREAKFLOWFLASHINGFRACTIONDURINGTHEGINNAEVENTFIGUREIII.l-lBREAKFLOWFLASHINGFRACTIONFORTHEDESIGNBASISEVENTDOSEANALYSISFIGUREIII.1-2'TTENUATIONFACTORFORFLASHEDCOOLANTFORTHEDESIGNBASISEVENTDOSEANALYSIS

'ISTOFFIGURES(Continued)FIGUREIII.1-3FAULTEDSTEAMGENERATORPARTITIONFACTORFORTHEDESIGNBASISEVENTDOSEANALYSISFIGUREIII.2-1BREAKFLOWFLASHINGFRACTIONFORTHEGINNAEVENTDOSEANALYSISFIGUREIII.2-2ATTENUATIONFACTORFORFLASHED.COOLANTFORTHEGINNAEVENTDOSEANALYSISFIGUREIII.2-3FAULTEDSTEAMGENERATORPARTITIONFACTORFORTHEGINNAEVENTDOSEANALYSIS I.INTRODUCTIONPotentialenvironmentalconsequencesofasteamgeneratortuberuptureeventattheR.E.Ginnanuclearpowerplanthavebeenevaluatedtoverify.thatthestandardtechnicalspecificationlimitonprimarycoolantactivityisadeuateforGinna.MassreleaseswerecalculatedusingthecomputercodeLOFTRANwithconservativeassumptionsofbreaksize,condenseravailability,andvariousoperatorresponsetimes.Theeffectofsteamgeneratoroverfillandsubsequentwaterreliefthroughsecondarysidereliefvalveswasalsoaddressed.Conservativeassumptionsconcerningcoolantactivity,meteorology,andpartitioningbetweenliquidandvaporphaseswereappliedtothesemassreleasestodetermineanupperboundonsiteboundaryandlowpopulationzonedoses.BestestimatemassreleasesduringtheJanuary25,1982tubefailureeventatGinna,werealsocalculatedbasedonanalysespresentedinreference2.Thesereleaseswereusedtoestimatepotentialdoseswhichcouldhaveresulted,iftheaccidenthad.occurredwithcoolantactivitylimitsestablishedinthe'standardtechnicalspecifications.

II.MASSRELEASES'assreleasesduringadesignbasissteamgeneratortuberuptureeventwerecalculatedusingestablishedfSARmethodologyassumingvariousoperatorresponsetimes.ReleasesduringtheGinnaeventwerealsoestimated.Contributionsfromboththeintactandfaultedsteamgeneratorswereevaluatedaswellasflowtothecondenserandatmosphere.Thesemassreleasesarepresentedforvarioustimeperiodsduringtheaccident.Theassumptionsandmethodologywhichwereusedtogeneratetheresults+redescribedinthefollowingsections.II.lDesignBasisAccidentTheaccidentexaminedisthecompleteseveranceofasinglesteamgeneratortubeduringfullpoweroperation.ThisisconsideredaconditionIVevent,alimitingfault,andleadstoanincreaseinthecontaminationofthesecondarysystemduetoleakageofradioactivecoolantfromtheRCS.Dischargeofacti-vitytotheatmospheremayoccurviathesteamgeneratorsafetyand/orpoweroperatedreliefvalves.Theconcentrationofcontaminantsintheprimarysystemiscontinuouslycontrolledtolimitsuchreleases.II.1.1SequenceofEventsIfnormaloperationofthevariousplantcontrolsystemsisassumed,thefol-lowingsequenceofeventsisinitiatedbyatuberupture:A.Thesteamgeneratorblowdownliquidmonitorand/orthecondenserairejectorradiationmonitorwillalarm,indicatingasharpincreaseinradioactivityinthesecondarysystem.B.Pressurizerlowpressureandlowlevelalarmsareactuatedandchargingpumpflowincreasesinanattempttomaintainpressurizerlevel.Onthesecondarysidesteamflow/feedwaterflowmismatchoccursasfeedwaterflowtotheaffectedsteamgeneratorisreducedtocompensateforbreakflowtothatunit.

C.ThedecreaseinRCSpressureduetocontinuedlossofreactorcoolantinventoryleadstoareactortripsignalonlowpressurizerpressureorovertemperaturedelta-T.Plantcooldownfollowingreactortripleadstoarapiddecrease,inpressurizerlevelandasafetyinjectionsignal,initi-"atedbylowpressurizerpressure,followssoonafterreactortrip.Thesafetyinjectionsignalautomaticallyterminatesnormalfeedwatersupplyandinitiatesauxiliaryfeedwateraddition.D.Thereactortripautomaticallytripstheturbineand,ifoffsitepowerisavailable,thesteamdumpvalvesopenpermittingsteamdumptotheconden-ser.Intheeventofcoincidentstationblackout,asassumedintheresultspresented,thesteamdumpvalvesautomaticallyclosetoprotectthecondenser.Thesteamgeneratorpressurerapidlyincreasesresultinginsteamdischargetotheatmospherethroughthesteamgeneratorsafetyand/orpoweroperatedreliefvalves.E.Theauxiliaryfeedwaterandboratedsafetyinjectionflowprovideaheatsinkwhichabsorbsdecayheatandattenuatessteamingfromthesteamgene-rators.F.Safetyinjectionflowresultsinincreasingpressurizerwatervolumeataratedependentupontheamountofauxiliaryequipmentoperating.RCSpressureeventuallyequilibratesatapressuregreaterthantheaffectedsteamgeneratorpressurewheresafetyinjectionflowmatchesbreakflow.Theoperatorisexpectedtodeterminethatasteamgeneratortuberupturehasoccurredandtoidentifyandisolatethefaultysteamgeneratoronarestric-tedtimescalein'ordertominimizecontaminationofthesecondarysystemandensureterminationofradioactiverelease.totheatmospherefromthefaultyunit.Sufficientindicationsandcontrolsareprovidedtoenabletheoperator.tocompleterecoveryproceduresfromwithinthecontrolroom.Highradiationindicationsorrapidlyincreasingwaterlevelinanysteamgeneratorprovidesymptomsofthefaultedsteamgeneratorwhichensureidentificationbeforethewaterlevelincreasesabovethenarrowrange.Forsmallertubefailures,

samplingofthesteamgeneratorsforhighradiationmayberequiredforpositiveidentification.However,inthatcaseadditionaltimewouldbeavailablebeforewaterlevelincreasesoutofnarrowrange.Onceidentified,thefaultedsteamgeneratorisisolatedfromtheintactsteamgeneratorstominimizeactivityreleasesandasanecessarysteptowardestab-lishingapressuredifferentialbetweentheintactandfaultedsteamgenera-tors.TheMai'nSteamlineIsolationValves(NSIV)providethiscapability.IntheeventofafailureoftheMISVforthefaultedsteamgenerator,theNSIVfortheintactsteamgeneratorandtheturbinestopvalveensurearedundantmeansofisolation.Auxiliaryfeedwaterflowisterminatedtothefaultedunitinanattempttocontrolsteamgeneratorinventory.Thereactorcoolanttemperatureisreducedtoestablishaminimumof50Fsubcoolingmarginattherupturedsteamgeneratorpressurebydumpingsteamfromtheintactsteamgenerator.Thisassuresthattheprimarysystemwillremainsubcooledfollowingdepressurizationtothefaultedsteamgeneratorpressureinsubsequentsteps.Ifthecondenserisavailable,thenormalsteamdumpsystemisusedforthiscooldown.Isolationofthefaultedsteamgenera-torensuresthatpressureinthatunitwillnotdecreasesignificantly.IfthecondenserisunavailableoriftheMSIVforthefaultedsteamgeneratorfails,theatmosphericreliefvalveontheintactsteamgeneratorprovidesanalternativemeansofcoolingthereactorcoolantsystem.Theprimarypressureisreducedtoavalueequaltothefaultedsteamgenera-torpressureusingnormalpressurizerspray.Thisactionrestorespressurizerlevelassafetyinjectionflowinexcessofbreakflowreplacescondensedsteaminthepressurizer,andmomentarilystopsprimary-to-secondaryleakage.Ifnormalsprayisnotavailable,thepressurizerPORVsandauxiliaryspraysystemprovideredundantmeansofdepressurizingthereactorcoolantsystem.lTerminationofsafetyinjectionflowisrequiredtoensurethatbreakflowisnotreinitiated.Previousoperatoractionsaredesignedtoestablishsuffi-cientindicationsofadequateprimarycoolantinventoryandheatremovalsothatcorecoolingwillnotbecompromisedasaresultofSItermination.

Thissequenceofrecoveryactionsensuresearlyterminationofprimary-to-secondaryleakagewithorwithoutoffsitepoweravailable.Thetimerequiredtocompletetheseactionsareeventspecificsincesmallerbreaksmaybemoredifficulttodetect.Intheseanalyses,operatoractiontimeshavebeentreatedparametrically,rangingfrom30minutestoamaximumof60minutestocompletethekeyrecoverysequence.II.1.2MethodofAnalysisMassandenergybalancecalculationswereperformedusingLOFTRANtodetermineprimary-to-secondarymassleakageandtheamountofsteamventedfrom'eachofthesteamgeneratorspriortoterminatingsafetyinjection.Inestimatingthemassreleasesduringrecovery,thefollowingassumptionsweremade:A.Reactortripoccursautomaticallyasaresultoflowpressurizerpressureorovertemperaturedelta-T.Lossofoffsitepoweroccursatreactortrip.B.Followingtheinitiationofthesafetyinjectionsignal,allsafetyinjec-tionpumpsareactuated.Flowfromthenormalchargingpumpsisnotcon-sideredsinceitisautomaticallyterminatedonasafetyinjectionsignal.C.Thesecondarysidepressureisassumedtobecontrolledatthesafetyvalvepressurefollowingreactortrip.Thisisconsistentwithlossofoffsitepower.D.Auxiliaryfeedwaterflowisassumedthrottledtomatchsteamflowinallsteamgeneratorstocontrolsteamgeneratorlevel.Minimumauxiliaryfeedwatercapacityisassumed.Thisresultsinincreasedsteamingfromthesteamgenerators.E.Individualoperatoractionsarenotexplicitlymodeledintheanalysespresented.However,itisassumedthattheoperatorcompletestherecoverysequenceonarestrictedtimescale.Thistimeistreatedpara-metrically.

F.Forcaseswheresteamgeneratoroverfilloccurs,waterrelieffromthefaultedsteamgeneratortotheatmosphereisassumedequaltoanyaddi-tionalprimary-to-secondaryleakageafteroverfilloccurs.Steamlinevolumeisnotconsideredincalculatingthetimeofsteamgeneratorover-fil1.Priortoreactortripsteamisassumedtobereleasedtothecondenserfromthefaultedandintactsteamgenerators.Steamfromallsteamgeneratorsisdumpedtotheatmosphereafterreactortripsincethecondenserisunavailableasaresultofstationblackout.Extendedsteamreleasecalculations,i.e.afterbreakflowhasbeentermina-ted,reflectexpectedoperatoractionsasdescribedintheMestinghouseOwnersGroup'sEmergencyResponseGuidelines.Followingisolationofthefaultedsteamgenerator,itisassumedthatsteamisdumpedfromtheintactsteamgeneratortoreducetheRCStemperatureto50'Fbelowno-loadTavg.Fromtwotoeighthoursaftertubefailure,theRCScoolanttemperatureisreducedtoResidualHeatRemovalSystem(RHRS)operatingconditionsviaaddi-.tionalsteamingfromtheintactsteamgenerator.Furtherplantcooldowntocoldshutdown,iscompletedwiththeRHRS.Ifsteamgeneratoroverfilldoesnotoccur,thefaultedsteamgeneratorisdepressurizedbyreleasingsteamfromthatsteamgeneratortotheatmosphere.Analternatecooldownmethod,suchasbackfillintotheRCS,isconsideredifthefaultedsteamgeneratorfillswithwater.Inthatcaseadditionalsteamingoccursfromtheintactsteamgenerator.Theextendedsteamandfeedwaterflowsaredeterminedfromamassandenergybalanceincludingdecayheat,metalheat,energyfromoneoperatingreactorcoolantpump,andsensibleenergyofthefluidintheRCSandsteamgenerators.ThesequenceofeventsforthedesignbasisaccidentarepresentedinTableII.1.2-1.Theprimary-to-secondarycarryoverandsteamandfeedwaterflowsassociatedwitheachofthesteamgeneratorsareprovidedinTablesII.1.2-2andII.1.2-3forrecoverytimesof30and60minutes,respectively.Sinceindividualoperatoractionswerenotmodelled,thesystemresponseisthesameforbothcases.Mith30minuteoperatoractiontoterminatebreakflow, TABLEII.1.2-1DESIGNBASISACCIDENTSEQUENCEOFEVENTSEventManual(0)Time(Sec)Automatic(A)30MinRecovery60MinRecoveryTubeFailureReactorTripCondenserLostSISignalFeedwaterIsolationAFWInitiationAFWThrottledtoFaul.tedSGIsolationofFaultedSGSteamDumpRCSDepressurizationSGOverfillSITerminatedBreakFlowTerminatedRHRCooling27271271341871871800(1)lsoo(1).1800(1)1SOO<<)1800(1)28800272712713418718736oo(1)3600(1)3600(l)2S103600(1)3600(1)28800\(1)Theseeventsarenotactuallymodeledbutareassumedtooccurwithinthetimeindicated.

TABLEII.1.2-2MASSRELEASESDURINGADESIGNBASISSGTR:30MINUTERECOVERYFlow(ibm)0-TTRIPTimePeriodTTRIP-TTBRKTTBRK-22-TRHRRupturedSG:-Condenser-Atmosphere-Feedwater278200.0326050.0326400.00.00.00.00.02148021480IntactSG:-Condenser-Atmosphere-Feedwater273800.0371700.023050133700.01446502062000.0470000487600BreakFlow33251006480.00.0TTRIP=27.0sec=TimeofreactortripTTBRK=1800,sec=TimetoterminatebreakflowTRHR=28800sec=TimetoestablishRHRcooling ITABLEII.1.2-3MASSRELEASESDURINGADESIGNBASISSGTR:60MINUTERECOVERYFlow(ibm)TimePeriod0-TTRIPTTRIP-TMSEP-TSGOF-TTBRK-22-TRHRTMSEPTSGOFTTBRKRupturedSG:-Condenser27820-Atmosphere0.0-Feedwater326050.0335700.00.048300.00.00.00.00.0431710.00.00.00.0IntactSG:-Condenser27380-Atmosphere0.0-Feedwater371700.023370137000.0139013900.00.00.039067970501100380129600518700BreakFlow332510774248070431710.00.0TTRIP=27.0sec=TimeTMSEP=1930sec=TimeTSGOF=2810sec=TimeTTBRK=3600sec=TimeofreactortriptofillSGtomoistureseparatorstofillSG(w/osteamlinevolume)toterminatebreakflowTRHR=28800sec=TimetoestablishRHRcooling9 liquidlevelinfaultedsteamgeneratorremainsbelowthebottomofthemois-tureseparator,FigureII.1.2-1.Hence,forthiscase,partitioningbetweenthevaporandliquidphaseseffectivelyreducesradiologicalreleasesforthedurationoftheaccident.Fordelayedrecovery,case2,themoisturesepara-torbeginstofloodat32minutes.Thefaultedsteamgeneratoriscompletelyfilledby47minutes.Duringthistime,liquidentrainmentwithinthesteamflowwouldincreasesothattheeffectivenessofpartitioningwouldbereduced.Beyond47minutes,i.e.steamgeneratoroverfill,waterrelieffromthefaultedsteamgeneratorisassumedequaltobreakflow.Thefollowingisalistoffiguresofpertinenttimedependentparameters:FIGUREII.1.2-1FAULTEDSGWATERVOLUMEFIGUREII;1.2-2REACTORCOOLANTSYSTEMPRESSUREFIGUREII.1.2-3FAULTEDSGPRESSUREFIGUREII.1.2-4REACTORCOOLANTSYSTEMTEMPERATUREFIGUREII.1.2-5PRESSURIZERWATER.VOLUMEFIGUREII.1.2-6FAULTEDSGSTEAMFLOWFIGUREII.l.2-7BREAKFLOWFIGUREII.1.2-8BREAKFLOWFLASHINGFRACTIONII.2GINNAEVENTAdetailedthermal-hydraulicanalysisoftheGinnaeventisdescribedinreference2.Theresultsofthatanalysisformthebasisforthecalculationofthepotentialenvironmentalconsequences.ThegeneralsequenceofeventsduringtheGinnaaccident,TableII.2-1,wassimilartothedesignbasis10 7000.06000.05000.0S.G.VOLUf1E~i000.0I~~3000.0I2000.01000.00.0ClCDEDCDC)EDCDCDEVTINK(MIN)CDCDC7C)C)CDCDCDCDCD40IFIGUREII.1.2-1.FAULTEDSTEANGE)lERATORHATERVOLU)1E.11

2300.02250.02000.01750.01500.0a.1250.01000.0CL750.00500.00300.00ClClClClAJClmTIN'E(MlN)CDClClCDClCDI@1CDCDCDClCOFIGUREII.1.2-2.REACTORCOOLAilTSYSTEhPRESSURE.12 1200.01000.0800.00-600F00~<u0.00200.000.0C7CDCDCDAJCDClmTIHE(HIM>CDCDCDC7CDCDC)CDI/ICDCDCDFIGUREII.1.2-3.FAULTEDSTEAHGENERATORPRESSURE.13

700.00500.00F00.00Cl~300.00I~200.00100.000.0C)CDCDCDCDC4CDCDT1ME(M1H)CDCDCDCDCDCDCDlPICDCDCDcoFIGUREII.l.2-4.REACTORCOOLANTAVERAGETEi1PERATURE.

800.00?00.00500.00auF00.00XF00.00100.000;0CICICICICICICIAJCImTlNE(MlN)CICIFIGUREII.1.2-5.PRESSURIZERHATERVOLUtlE.15

0.20000.17500.1500OQ0.12500.1000CD0.0750CD0.05000.02500.0CICDCD8CDCDmTIME(HIM)CDCDCDCDlACDCDCDCOFIGUREII.1.2-6.FAULTEDSTEANGENERATORSTEANFLOW.16 150.00125.00100.00l5.000~50.00025.0000.0CDCDCDCDAJCDmTIME(MIN)CDCDCDCDCDIClCD0EDFIGUREII.l.2-7.PRIl1ARY-TQ-SECONDARYLEANGE.17

0.20000.17500.15000.1250I-0.10000.05000.0250'0.0CDCDCDCDflJCDmTIME(MIN)CDCDCDCDCDVlCDCDCD\FIGUREII.1-2-8.BREAKFLOllFLASHINGFRACTION.18 Jt TABLEII.2-1GINNASE()UENCEOFEVENTSEventManual(0)Automatic(A)ActualTime(sec)SimulatedTubeFailureReactorTripCondenserLost'ISignalFeedwaterIsolationAFWInitiatedAFWThrottledtoFaultedSGIsolationofFaultedSGSteamDumpRCSDepressurizationSGOverfillSITerminatedBreakFlowTerminatedRHRCoolingAAA00000.000182450019019222041089077027004310108007758001824500198198..2394105305302700313043101080077580includessteamlinevolume19

eventdescribedinsectionII.l.l.Breakflowinexcessofnormalcharging-flowdepletedreactorcoolantinventoryandeventuallyresultedinreactortriponlowpressurizerpressure.Asafetyinjectionsignalfollowedsoonaftertrip.Normalfeedwaterflowwasautomaticallyterminatedonthesafetyinjectionsignalandauxiliaryfeedwaterflowwasinitiated.Thesteamdumpsystemoperatedtocontrolsteamgene-ratorpressurebelowthesafetyvalvesetpointandestablishno-loadreactorcoolanttemperature.Auxiliaryfeedwaterand'afetyinjectionflowsabsorbeddecayheatandtemporarilystoppedsteamreleasesfromthesteamgenerators.Emergencyrecoveryactionswerequicklyinitiatedtomitigatetheconsequencesoftheaccident.Pre-tripsymptomsofthefaultedsteamgenerator,includingsteamflow/feedflowmismatchandsteamgeneratorleveldeviationalarms,providedtentativeindicationsofthefaultedsteamgeneratorwhichwerecon-firmedsoonafterreactortripbyrapidlyincreasingsteamgeneratorlevelandhighradiationindications.Auxiliaryfeedwaterflowwasreducedtothefaultedunitinanattempttocontrolinventory.Isolationofthefaultedsteamgeneratorwascompletedwithin15minutesoftubefailurebyclosingtheassociatedMSIV.Continuedauxiliaryfeedwaterflowtotheintactsteamgene-ratoreffectivelyreducedtheprimarysystemtemperaturetoestablish50Fsubcoolingmargin.Normalspraywasunavailablesincereactorcoolantpumpsweremanuallytrippedsoonafterreactortripasdirectedbyemergencyproce-dures.Consequently,onepressurizerPORVwasusedasanalternativemeansofdepressurizingtheprimarysystemtorestorepressurizerlevelandreducebreakflow.Thiswascompletedwithin45minutes.Safetyinjectionflowwassubsequentlyterminatedafter72minutes.Continuedchargingflowandreini-tiationofsafetyinjectionflowresultedinadditionalprimary-to-secondaryleakageuntilapproximately3hrsaftertubefailure.MassreleasesduringtheGinnaeventarepresentedinTableII.2-2.LOFTRANresultsindicatethatthefaultedsteamgeneratorandsteamlinefilledwithwaterafterapproximately52minutes,FigureII.2-1.Beyondthistimewaterrelieffromthefaultedsteamgeneratorwasassumedequaltoanyadditionalprimary-to-secondaryleakage.Themeasuredprimaryandfaultedsteamgenera-torpressuresandcalculatedbreakflowflashingfractionduringtheaccident20

TABLEII.2-2BESTESTIMATEMASSRELEASESDURINGGINNASGTREVENTFlow(ibm)TimePeriod0-TTRIPTTRIP-TMSEP-TSGOF*-22-TTBRKTTBRK-TMSEPTSGOF*TRHRFaultedSG:-Condenser162100-Atmosphere0-Feedwater16340016900046800013044200105684,0~0IntactSG:-Condenser160100-Atmosphere.0-Feedwater1717002880025200145000.02387052300089700054743530080978387983292BreakFlow103005433099170130442105684TTRIP=182.0sec=TimeofreactortripTMSEP=1335sec=TimetofillSGtomoistureseparatorTSGOF=2192sec=TimetofillSGTSGOF*=3131sec=TimetofillSGandsteamlineTTBRK=10200sec=TimetoterminatebreakflowTRHR=77580sec=TimetoestablishRHRcooling21 7000.06000.0S.G.ANDSTEAr>LINEVOLUWE5000.0S.G.VOLUtlEF000.0I~)3000.0I2000.01000.00.0CDCDCDCDIAAJCDCDCDCDCDi/IPeaCDCDCDTlHE<HlN)CDCDV1AJCDCD"tAOOG)D~~AO(QFIGUREII.2-1.CALCULATEDFAULTEDSTEAHGENERATORMATERVOLUt1EDURINGTHEGINNAEVENT.22 2300.02250.02000.01750.01500.0C1250.0GGGG1000.0,0.GGG750.00500.00300.00CIEDCDItlAJC)EDIAClDOO~~If)Q(oTlME(MlN)FIGUREII22REACTORCOOLANTSYSTEi~'1PRESSUREDURIHGTHEGIHHAEYEHT.23 1200.01000.0cc800.00~600.00~F00.00CL200.000.0ClClClClCllAAJClCDClClCDClCII/ITIME(MIN)ClCDCDClCDClIllAJCDClIClOOOO~~IOOFIGUREII.2-3.FAULTEDSTEAhGENERATORPRESSUREDURINGTHEGINNAEVENT.

0.20000i)50005000.025000CITENTtNttllFIGUREII.2-4.CALCULATEDBREAKFLOliFLASHI(HGFRACTIONDURINGT)lEGIN(iAEVEiPT.25 arepresentedinFiguresII.2-2thruII.2-4.Theseresultsshowthatapproxi-mately236,000ibmofmasswerereleasedafterthefaultedsteamgeneratorandsteamlinewascalculatedtofillwithwater.Approximately130,000ibmofthiswerereleasedinthefirst2hrs.Steamflowtocondenserwasterminatedatapproximately75minutes.MassreleaseswereterminatedwhentheRHRSwasplacedinserviceafter21.5hrs.\26

III.ENVIRONMENTALCONSEQUENCESANALYSISIntroduc.tionFortheevaluationoftheradiologicalconsequencesofasteamgeneratortuberupture,itisassumedthatthereactorhasbeenopertingwithasmallpercentofdefectivefuelforsufficienttimetoestablishequilibriumconcentrationsofradionuclidesinthereactorcoolant.Hence,radionuclidesfromthe'rimarycoolantenterthesteamgenerator,viatherupturedtube,andarereleasedtotheatmospherethroughthesteamgeneratorsafetyorpoweroperatedreliefvalves.Theradioactivityreleasedtotheenvironment,duetoaSGTR,dependsuponprimaryandsecondarycoolantactivity,iodinespikingeffects,primarytosecondarybreakflow,timedependentbreakflowflashingfractions,timedependentscrubbingofflashedactivity,partitioningoftheactivityfromthenonflashedfractionofthebre'akflowbetweenthesteamgeneratorliquidandsteamandthemassoffluiddischargedtotheenvironment.Alloftheseparameterswereconservativelyevaluatedforadesignbasistubefailure,i.e.doubleendedruptureofasingletube,asdescribedinSectionII.1.ThemassreleasesduringtheGinnaeventwerealsoestimatedinSectionII.2.Theenvironmentalconsequencesattheseeventswerecalculatedandarediscussedinthefollowingsections.III.lDESIGNBASESANALYTICALASSUMPTIONSThemajorassumptionsandparametersusedintheanalysisareitemizedinTableII.l-landaresummarizedbelow.27

SourceTermCalculationsTheconcentrationsofnuclidesintheprimaryandsecondarysystem,priortotheaccidentaredeterminedasfollows:a.Theiodineconcentrationsinthereactorcoolantwillbebaseduponpreaccidentandaccidentinitiatediodinespikes.i.PreaccidentSpike-AreactortransienthasoccuredpriortotheSGTRandhasraisedtheprimarycoolantiodineconcentrationto60pCi/gramofDoseEquivalentI-131.ii.AccidentInitiatedSpike-ThereactortriporprimarysystemdepressurizationassociatedwiththeSGTRcreatesaniodinespikeintheprimarysystemwhichincreasestheiodinereleaseratefromthefueltotheprimarycoolanttoavalue500timesgreaterthanthereleaseratecorrespondingtothemaximumequilibriumprimarysystemiodineconcentrationoflpCi/gramofDoseEquivalent(D.E.)I-131.Thedurationofthespikeisassumedtobe4hours.IodineappearanceratesinthereactorcoolantarepresentedinTableIII.1-2.Dosesarecalculatedforbothcasesofspiking.b.Thenoblegasactivityinthereactorcoolantisbasedon1percentfueldefects,asprovidedinTableIII.1-3.Theassumptionof1percentfueldefectsforthecalculationofnoblegasactivity,isconservative,sincelpCi/gramD.E.I-131and1percentdefectscannotexistsimultaneously.Iodineactivitybasedon1percentdefectswouldbegreaterthantwicetheStandardTechnicalSpecificationlimit.c.ThesecondarycoolantactivityisbasedontheO.E.of0.1pCi/gramofI-131.d.Iodineattherupturepointisassumedtoconsistof99.9percentelementaland0.1percentorganiciodine.28

'IDoseCalculationsThefollowingassumptionsandparametersareusedtocalculatetheactivityreleasedandtheoffsitedosesfollowingaSGTR.a.Themassofreactorcoolantdischargedintothesecondarysystemthroughtheruptureandthemassofsteamand/orwaterreleasedfromtheintactandfaultedsteamgenerators,totheenvironmentispresentedinTablesII.1.2-2and3.b.Thetimedependentfractionofrupture'flowthatflashestosteamandisimmediatelyreleasedtotheenvironmentisshowninFigureIII-l-l.c.ThetimedependentelementaliodineattenuationfactorforretentionofatomizedprimarydropletsbythemoistureseparatorsanddryersandforscrubbingofsteambubblesastheyrisefromtheleaksitetothewatersurfaceispresentedinFigureIII.1-2.Retentionbymoistureseparatorsandscrubbingareeffectedbydifferentialpressure(aP)acrosstherupturedtubeandwaterlevel.,Specificallyforthefirst4minutesdPisassumedtobe.high(>1000psi)andwaterlevellow(justabovetopoftubebundle).Forthisperiod,neitherretentionnorscrubbingisassumedandtheoverallfactoris1.0.Fortimesgreaterthan4minutes,theaPdecreasestoapproximately300psiandremainsconstant.fortimesgreaterthan4butlessthan32minutes,retentionbytheseparatorsisconstantandatamaximum.At32minutestheseparatorsbegintofloodandat47minutesthegeneratorisfilled.Retentionbytheseparatorsdecreasesfromthemaximumat32minutestozeroat47minutes.Scrubbingincreaseswithrisingwaterlevel.d-The1gpmprimarytosecondaryleakisassumedtobesplitevenlybetweenthesteamgenerators.29

e.Allnoblegasactivityin.thereactorcoolantwhichistransportedtothesecondarysystemviathetuberuptureandtheprimary-to-secondaryleakageisassumedtobeimmediatelyreleasedtotheenvironment.f.CaseIassumes30minuteoperatoractiontoteminatebreakflow.TheliquidlevelinthefaultedSGremainsbelowthemoistureseparator.Case2assumes60minuteoperatoraction.Themoistureseparatorbeginstofloodat32minutesandthegeneratorisfilledat47minutes.g.TheelementaliodinepartitionfactorbetweentheliquidandsteamoftheintactSGisassumedtobe100.ThetimedependentpartitionfactorforthefaultedSGispresentedinFigureIII.1-3.h.Offsitepowerislostfollowingreactortrip.i..Eighthoursafter.theaccident,theRHRsystemisassumedtobeinopera'tion'tocooldowntheplant.Thus,noadditionalsteamreleaseisassumed.j.Neitherradioactivedecay,duringreleaseandtransport,norground~~~~~~~~depositionofactivitywasconsidered.k.Short-termatmosphericdispersionfactors(x/g's)foraccidentanalysisandbreathingratesareprovidedinTableIII.1-4.1.Decayconstants,averagebetaandgammaenergiesandthyroiddoseconversionfactorsarepresentedinTableIII.1-5.30

OFFSITETHYROIDDOSECALCULATIONMODELOffsitethyroiddosesarecalculatedusingtheequationwhereTh(IAR)integratedactivityofisotopeireleased*duringthetimeintervaljinCiandbreathingrateduringtimeintervaljinmeter/secondoffsiteatmosphericdispersionfactorduringtimeintervaljinsecond/meter(DCF).thyroiddoseconversionfactorviainhalationforisotopeiinrem/CithyroiddoseviainhalationinremsOFFSITETOTAL-BODYDOSECALCULATIONALMODELAssumingasemi-infinitecloudofbetaandgammaemitters,offsitetotal-bodydosesarecalculatedusingtheequation:DTB025Z5;g(IAR);.(XID).ij31 whereIntegratedactivityofisotopeireleased*duringthejtimeintervalinCiandoffsiteatmosphericdispersionfactorduringtimeintervaljinsecond/meterE-conservativelyassumedtobethesumofthebetaandgammaenergyfortheiisotopeinmev/dis.'TBtotal-bodydoseinrems*Nocreditistakenforclouddepletionbygrounddeposition.andradioactivedecayduringtransporttotheexclusionareaboundaryortotheouterboundaryofthelow-.populationzone.ResultsThyroidandTotal-BodydosesattheSiteBoundaryandLowPopulationZonearepresentedinTableIII.1-6.Alldosesarewithintheguidelinesof10CFR100.32 I

TABLEIII.1-1PARAMETERSUSEDINEVALUATINGTHERADIOLOGICALCONSEQUENCESOFASTEANGENERATORTUBERUPTURE(SGTR)SourceDataa.Corepowerlevel,MWtb.Steamgeneratortubeleakage,gpmc.Reactor-coolantiodineactivity:152011..AccidentInitiatedSpikeInitialactivityequaltothedoseequivalentof1.0pCi/gmofI-131withanassumediodinespikethatincreasestherateofiodinereleaseintothereactorcoolantbyafactorof500.SeeTablesIII.1-2and3.2.Pre-AccidentSpikeAnassumedpre-accidentiodinespike,whichhasresultedinthedoseequivalentof60pCi/gmofI-131inthereactorcoolant.d.Reactorcoolantnoblegasactivity,bothcasesBasedon1-percentfailedIfuelasprovidedinTableIII.1-3.33 TABLEIII.1-1[Sheet2)e.SecondarysysteminitialactivityDoseequivalentofO.lpCi/gmofI-131f.Reactorcoolantmass,gramsg.Steamgeneratormass(each),grams1.27x103.39x10h.OffsitepowerLosti.Primary-to-secondary!1eakagedurationj.Speciesofiodine99.9percentelemental0.1percentorganicCase1-30minCase2-60minII.AtmosphericDispersionFactorsIII.ActivigReleaseDataSeeTableIII.1-4a.Faultedsteamgenerator1.Reactorcoolantdischargedtosteamgenerator,lbs.SeeTableIII.1.2-2or32.Flashedreactorcoolant,fractionSeeFigureIII.1-13.IodineattenuationfactorforflashedfractionofreactorcoolantSeeFigureIII.1-2I34 TABLEIII.1-1(Sheet3)4.Totalsteamrelease,lbsSeeTableIII.1.2-2or35.IodinepartitionfactorforthenonflashedfractionofreactorcoolantthatmixeswiththeinitialiodineactivityinthesteamgeneratorSeeFigureIII.1-3t6.LocationoftuberuptureTopofBundleb.Intactsteamgenerator1.Primary-to-secondary1ca/age,1bs/hr1802.Flashedreactor.coolant,fraction3.Totalsteamrelease,lbsSeeTableIII.1.2-2or34.Iodinepartitionfactor1005.Isolationtime,hrs35 TABLEIII.1-2IODINEAPPEARANCERATESINTHEREACTORCOOLANT{CURIES/SECOND)FORADESIGNBASISSGTRI-131I-132I-133I-134I-135EquilibriumAppearanceRatesduetoTechnicalSpecificationFueldefects1.88x104.44x103.48x106.14x104.68x10AppearanceRatesduetoanIodineSpike-500Xequilibriumrates0.942.221.743.072.34 TABLEIII.1-3.REACTORCOOLANTIODINEANDNOBLEGASACTIVITYNuclide*IodineActivitybasedon1pCi/gramofDoseEquiv.I-131I-131I-132I-133I-134I-1350.785pCi/gram0.3441.010.2040.787NobleGasActivityBasedon1percentFuelDefectsXe-131mXe-133mXe-133Xe-135mXe-135Xe-138Kr-85mKr-85Kr-87Kr-881.8pCi/gram152400.417.980.4542.046.91.183.58*Secondarycoolantiodineactivityisbasedon0.1pCi/gramofDoseEquivalentI-131andistherefore10percentofthesevalues.37 TABLEIII.1-4'HORT-TERNATt10SPHERICDISPERSIONFACTORSANDBREATHINGRATESFORACCIDENTANALYSISTimeSiteBoundary~j(hours)x/g(Sec/m)LowPopulation~jZonex/g(Sec/m)3Breathing~jRate(m/Sec)0-20-848x1043x10~3.47x1043.47x1038 TASLEIII.1-5ISOTOPICDATADecayConstant~Isotoe(UHr)EY(Mev/dis)E~(Mev/dis)DCF~8j(R/ci)I-131I-132I-133I-134I-1350.003590.3010.0330.8000.1031.49(6)1.43(4)2.69(5)3.73(3)5.60(4)Xe-131mXe-133m0.002450.01280.00290.0200.1650.212Xe-1330.005480.030.153Xe-135mXG-135Xe-1382.670.07532.450.430.251.20.0990.320.66Kr-85mKr-85Kr-87Kr-880.1580.000007350.5470.2480.160.00230.793,2.210.250.2511.330.2539

TABLE111.1-6RESULTSOFDESIGNBASISANALYSISDoses(Rem)Case1Case21.AccidentInitiatedIodineSpikeSiteboundary0-2hr.)ThyroidTota1-body2.90.3191.50.5LowPopulationZone(0-8hr)ThyroidTota1-body0.190.025.70.032.Pre-AccidentIodineSikeSiteboundary(0-2hr)ThyroidTota1-body22.30.312730.5LowPopulationZone(0-8hr)ThyroidTota1-body1.40.0217.10.0340 FIGURE:III.1-1O.)0000.08000.0600OI-'K4.0.0400ID.O.ozooTIMEINTERVALIMINUTES)0IS)5-3D30-505D-60)60FRACTION0.0550.020'0.0I0.0030.00.000000000000000P)00000000IA00000000000IflTIME(MIN)BREAKFLOWFLASHINGFRACTION

FIGURE:l~1>2ZO30AO5060TIMEtMINUTES)ATTENUATIONFACTORFORFLASHEOREACTORCOOLANT42 l0050O40a30020l0NORMALLEVEL3047TOBOTTOMS.G.OFMOISTUREFILLEDSEP.TIME(MINUTES)FAULTEDS.G.PARTITIONFACTORFORNONFLASHEDREACTORCOOLANT43

III.2BestEstimateAnalyticalAssumptionsThemajorassumptionsandparametersusedintheanalysisareitemizedinfaoleIII.2-1andaresummarizedbelow.SourceTermCalculations)heconcentrationsofnuclidesintheprimaryandsecondarysystem,priortotheaccidentaredeterminedasfollows:a.Theiodineconcentrationsinthereactorcoolantwillbebaseduponpreaccidentandaccidentinitiatediodinespikes.L~i.PreaccidentSpike-AreactortransienthasoccurredpriortotheSGTRandhasraisedtheprimarycoolantiodineconcentrationto8pCi/gramofDoseEquivalentI-131.(ThebasisforthespikingfactorsispresentedinRef.9.)ii.AccidentInitiatedSpike-ThereactortriporprimarysystemdepressurizationassociatedwiththeSGTRcreatesaniodinespikeintheprimarysystemwhichincreasestheiodinereleaseratefromthetueltotheprimarycoolanttoavalue30L~timesgreaterthanthereleaseratecorrespondingtothemaximumequilibriumprimarysystemiodine.concentrationoflpCi/gramofDoseEquivalent(O.E.)1-13l.Thedurationoftnespikeisassumedtobe4hours.IodineappearanceratesinthereactorcoolantarepresentedinTable2.Dosesarecalculatedforbothcasesofspiking.b.Thenoblegasactivityinthereactorcoolantisbasedon1-percentfueldefects,asprovidedinTable3ofPartIII.l.c.TnesecondarycoolantactivityisbasedontheO.E.ofO.luCi/gramofI-131.d.Iodineattherupturepointisassumedtoconsistof100percentelementaliodine.

Theassumptionof1-percentfueldefectsforthecalculationofnoblegasactivityisconservativesincelgCi/gramD.E.I-131andIpercentdefectscannotexistsimultaneously.IodineactivitybasedonIpercentdefectswouldbegreaterthantwicetheTechnicalSpecificationlimit.DoseCalculationsThefollowingassumptionsandparametersareusedtocalculatetheactivityreleasedandtheoffsitedosesfollowingaSGTR.a.Themassofreactorcoolantdischargedintothesecondarysystemthroughtheruptureandthemassofsteamand/orwaterreleasedfromtheintactandfaultedsteamgenerators,totheenvironmentispresentedinTableIII.2-2.b.ThetimedependentfractionofruptureflowthatflashestosteamandisimmediatelyreleasedtotheenvironmentisshowninFigureIII.2-1.c.ThetimedependentelementaliodineattenuationfactorforretentionofatomizedprimarydropletsbythemoistureseparatorsanddryersandforscrubbingofsteambubblesastheyrisefromtheleaksitetothewatersurfaceispresentedinFigureIII.2-2.Retentionbymoistureseparatorsandscrubbungareeffectedbydifferentialpressure(aP)acrosstherupturedtubeandwaterlevel.Specificallyforthefirst5minutessPisassumedtobehigh(550psi)andwaterlevellow(topoftubebundle).Forthisperiod,retentionandscrubbingareassumedandtheoverallfactoris1.45.Fortimesgreaterthan5minutestheaPdecreasestoapproximately450psiandisassumedconstantforthedurationoftheflashingperiod.fortimesgreaterthan5butlessthan22minutes,retentionbytheseparatorsisassumedconstantandatamaximum.At22minutestheseparatorsbegintofloodandat52minutesthegeneratorandsteamlinearefilled.Retentionbytheseparatorsdecreasesfromthemaximumat5minutesto.zeroat36minutes.Scruobingincreaseswithrisingwaterlevel..

d.TheIgpmprimarytosecondaryleakisassumedtobesplitevenlybetweenthesteamgenerators.e.Allnoblegasactivityinthereactorcoolantwhichis"transportedtothesecondarysystemviathetuberuptureandtheprimary-to-secondaryleakageisassumedtobeimmediatelyreleasedtotheenvironment.f.Themoistureseparatorbeginstofloodat22minutesandthegeneratorandsteamlinearefilledat52minutes.g.TheelementaliodinepartitionfactorbetweentheliquidandsteamoftheintactSGisassumedtobe5000.ThetimedependentpartitionfactorforthefaultedSGispresentedinFigureIII.2-3.h.Offsitepowerisavailable.i.21.5hoursaftertheaccident,theRHRsystemisassumedtobeinopera-tiontocooldowntheplant.Thus,noadditionalsteamreleaseisassumed.~~~~~~j.Neitherradioactivedecay,duringreleaseandtransport,norgrounddepositionofactivitywasconsidered.k.Short-termatmosphericdispersionfactors(X/g's)foraccidentanalysisandbreathingratesareprovidedinTableIII.2-3.l.Decayconstants,averagebetaandgammaenergiesandthyroiddoseconver-sionfactorsarepresentedinTable5ofPartIII.1.OffsiteThyroidandTotal-8odyDoseCalculationalModelsSeePartIII.1ResultsThyroidandtotal-bodydosesatthesiteboundaryandlowpopulationzonearepresentedinTableIII.2-4.Alldosesarewithintheguidelinesof10CFR100.46

TABLEIII.2-1PARAMETERSUSEDINTHEBESTESTIMATEEVALUATIONTHERADIOLOGICALCONSEQUENCESOFTHEGINNAEVENTI.SourceDataa.Corepower1evel,MNtb.Steamgeneratortube1eakage,gpmc.Reactorcoolantiodineactivity:152011.AccidentInitiatedSpikeInitialactivityequaltothedoseequivalentof1.0pCi/gmofI-131withanassumediodinespikethatincreasestherateofiodinereleaseintothereactorcoolantbyafactorof30.SeeTablesIII.2-2,III.1-3.2.Pre-AccidentSpikeAnassumedpre-accidentiodinespike,whichhasresultedinthedoseequivalentof8pCi/gmofI-131inthereactorcoolant.d.ReactorcoolantnoblegasactiviBasedon1-percentfailedfuelAsprovidedinTableIII.1-3ofSectionIII.1e.Secondarysysteminitialactivityf.Reactorcoolantmass,gramsg.Steamgeneratormass(each)gramsh.OffsitepowerDoseequivalentof0.1pCi/gmofI-131.1.27x1083.39x10Available47 TABLEIII.2-1(Continued)Primary-to-secondaryleakagedurationj.Speciesofiodine185min100percentelementalII.AtmosphericDispersionFactorsSeeTableIII.2-3III.ActivityReleaseDataa.Faultedsteamgenerator1.Reactorcoolantdis-chargedtosteamgenerator,lbs.SeeTableII.2-22.Flashedreactorcoolant,fraction3.Iodineattenuationfactorforflashedfractionofreactorcoolant4.Steamandwaterreleases,lbs5.Iodinepartitionfactorforthenonflashedfractionofreactorcoolantthatmixeswiththeinitialiodineactiviginthesteamgenerator6.LocationoftuberuptureSeeFigureIII.2-1SeeFigureIII.2-2SeeTableII.2-2SeeFigureIII.2-34inchesabovetubesheetb.Intactsteamgenerator1.Primary-to-secondaryleakage,lbs/hr180

TABLEIII.2-1(Continued)2.Flashedreactorcoolant3.4~fractionTotalsteamrelease,lbsIodinepartitionfactorIsolationtime,hrsSeeTableII.2-2500021.55c.Condenser1.Iodinepartitionfactor500049

TABLEIII.2-2IODINEAPPEARANCERATESINTHEREACTORCOOLANT(CURIES/SECOND)I-131I-133I-134I-135EquilibriumAppearanceRatesduetoTechnicalSpecificationfuelDefects1.88x104.44x103.48x106.14x104.68x10AppearanceRatesduetoanIodineSpike-30Xequilibriumrates5.64x101.33x101.04x101.84x101.4x10 TABLEIII.2-3SHORT-TERMATMOSPHERICDISPERSIONFACTORSAND8REATHINGRATESFORACCIDEWTANALYSESTime(hours)SiteBoundaryx/q(Sec/m)LowPopulationZonex/g(Sec/m)BreathingRate(m/sec)0-24.8x103.47x100-83x103.47x108-243x101.75x10Note:x/g'sare10percentoftheR.G.1.145values.51

TABLEIII.2-4RESULTSOFGINNAEVENTANALYSES1.AccidentInitiatedIodineSpikeDoses(Rem)Siteboundary(0-2hr)ThyroidTota1-body2.90.5LowPopulationZone(0-8hr)ThyroidTotal-body1.40.0482.PreAccidentSikeSiteboundary(0-2hr)ThyroidTota1-body8.50.5LowPopulationZone(0-8hr)ThyroidTota1-body1.50..04852 P

FIGuRE:III21O.ZOOOO.l750O.l500O.IZ50OO.IOOOCDK0.07504xCA0.05004.O.OZ50IIIIITIMEINTERVAL(MINUTES)06Sl70'7FRACTION0.!60.0280.00.0OlAEV0OlAolA0OtAAl0OlA0olAO~rCOTIME(MIN)BREAKFLOWFLASHINGFRACTIONFORTHEGINNAEVENT53 1098IOI520Tll4EIMlNUTES)30ATTENUATIONFACTORFORFLASHEDREACTORCOOLANTFORTHEGlNNAEVENT54

5000a:1000OfOf-.F-100IIIIIIIIIIIIIIIIIIIIIIIII10ZO3060TIMEIMlNUTES)FAULTEDS.G.PARTIT10NFACTORFOR'HEGINNAEVENT,I55

IV.SUMMARYANDCONCLUSIONSThepotentialenvironmentalconsequencesofasteamgeneratortubefailureattheR.E.Ginnanuclearpowerplantwereevaluatedinordertodemonstrate~~~~~~~thattheStandardTechnicalSpecificationslimitonprimarycoolantactivityisacceptable.Themassreleasesduringadesignbasisevent,i.e.adoubleendedruptureofasingletube,wereconservativelycalculatedusingthecom-putercodeLOFTRAN.Fortheseanalyses,thesequenceofrecoveryactionsinitiatedbythetubefailurewereassumedtobecompletedonarestrictedtimescale.Twocaseswereconsidered:a)30minuterecovery,andb)60min'uterecovery.Theeffectofsteamgeneratoroverfil1onradiological'eleaseswasalsoconsidered.Massreleasesduringthedesignbasiseventwereusedwithconservativeassumptionsofcoolantactivity,meteorology,andattenuationtoestimateanupperboundofsiteboundaryandlowpopulationzoneexposures.ThemassreleasesfromtheJanuary25,1982steamgeneratortubefailureatGinnawerealsocalculatedfromresultspresentedinreference2.ThesereleaseswereusedwiththeStandardTechnicalSpecificationlimitoninitialcoolantactivityandamorerealisticmeteorologytoevaluatepotentialdosesonamorerealisticbasis.Resultsofthedesignbasisanalysesindicatethattheconservativesiteboundaryandlowpopulationzoneexposuresfromasteamgeneratortubefailurearewithin10CFR100limitationswiththeStandardTechnicalSpecificationlimitoninitialcoolantactivity.Estimatesofthepotentialradiologicalreleasesfromamorerealisticeventwiththesameinitialcoolantactivitydemonstratethatthedesignbasisanalysisisveryconservative.Conse-quently,theStandardTechnicalSpecificationlimitoncoolantactivityaresufficienttoensurethattheenvironmentalconsequencesofasteamgeneratortubefailureattheR.E.Ginnaplantwillbewithinacceptablelimits.56 REFERENCES1.L.A.Campbell,"LOFTRANCODEDESCRIPTION",WCAP-7878Rev.3,January(1977).2.E.C.Volpenhein,"ANALYSISOFPLANTRESPONSEDURINGJANUARY26,1982STEANGENERATORTUBEFAILUREATTHER.E.GINNANUCLEARPOWERPLANT",WestinghouseElectricCo.,October(1982).3.WESTINGHOUSEOWNERSGROUPEMERGENCYRESPONSEGUIDELINESSElfINAR,September1981.4.NRCStandardReviewPlan15.6-3,Rev.2,"RadiologicalConsequencesofaSteamGeneratorTubeFailure",Ju'ly,1981.5.NRCNUREG-0409,"IodineBehaviorinaPWRCoolingSystemFollowingaPostulatedSteamGeneratorTubeRuptureAccident",Postma,A.K.,Tam,P.S.,Jan.1978.6-NRCRegulatoryGuide1.145,"AtmosphericDispersionModelsforPotential.AccidentConsequenceAssessmentsatNuclearPowerPlants",August,1979.7.-NRC.Regulatory-Guide1.4,Rev.2,"AssumptionsUsedforEvaluatingthePotentialRadiologicalConsequencesofaLOCAforPressurizedMaterReactors",June1974.8.NRCRegulatoryGuide1.109,Rev.1,"CalculationofAnnualDosestoManFromRoutineReleasesofReactorEffluentsforthePurposeofEvaluatingCompliancewith10CFRPart50AppendixI",Oct.1977.9.Lutz,R.J.,"IodineandCesionSpikingSourceTermsforAccidentAnalysis,"MCAP-9964,Rev.1,July1981.57