ML17256A402

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Analysis of Plant Response During 820125 Steam Generator Tube Failure at Re Ginna Nuclear Power Plant.
ML17256A402
Person / Time
Site: Ginna Constellation icon.png
Issue date: 11/22/1982
From: VOLPENHEIN E C
WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP.
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3274Q:1-111782, NUDOCS 8211290429
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ATTACHMENT AANALYSISOFPOTENTIAL ENVIRONMENTAL CONSEQUENCES FOLLOWING ASTEAMGENERATOR TUBEFAILUREATR.E.GINNANUCLEARPOWERPLANTNOVEMBER1982Preparedby:K.RubinE.Volpenhein Westinghouse ElectricCorporation NuclearEnergySystemsP;0.Box355Pittsburgh, Pennsylvania 15230Preparedfor:Rochester GasandElectric89EastAvenueRochester, NewYork14649ggffg+O4PP 821122PDRADOCK05000244PPDR TABLEOFCONTENTSSectionPageABSTRACT~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~1LISTOFTABLESLISTOFFIGURES....................

~....,..ivI.INTRODUCTION

.....~1II.MASSRELEASESII.lDesignBasisAccident.II.l.lSequenceof,EventsII.1.2MethodofAnalysisII.2GinnaEvent.~~~2~~~2~~~2~~~510III.ENVIRONMENTAL CONSEQUENCES ANALYSISIII.lDesignBasisAccidentIII.2GinnaEventAnalysis.~~~~~~~27~~~~~~027~~~~~~o4DIV.SUMMARYANDCONCLUSIONS

~~~~~~o56'REFERENCES

i~~~~~~~~57 ABSTRACTThepotential radiological consequences ofasteamgenerator tubefailureeventwereevaluated fortheR.E.Ginnanuclearpowerplanttodemonstrate thatstandardlimitations oninitialcoolantactivityareacceptable.

Massreleasesfollowing adesignbasistuberupturewerecalculated forboth30minuteand60minuteoperatorresponsetimes.Thesiteboundaryandlowpopulation zoneexposures wereconservatively calculated forthesereleases.

'naddition, thestandardtechnical specification limitoninitialcoolantactivityandrealistic meteorology wereappliedto"bestestimate" mass"releaseduringtheJanuary25,1982tubefailureeventatGinna.Resultsshowthattheconservative assessment oftheenvironmental consequences arewithinacceptable limitsandthatthepotential exposurefromamorerealistic eventisminimal.

LISTOFTABLESTABLEII.1.2-1DESIGNBASISACCIDENTSEQUENCEOFEVENTSTABLEII.1.2-2.MASSRELEASESDURINGADESIGNBASISSGTR:30MINUTERECOVERYTABLEII.1.2-3MASSRELEASESDURINGADfSIGNBASISSGTR:60MINUTfRECOVERYTABLEII.2-1TABLEII.2-2GINNASEQUENCEOFEVENTSBESTESTIMATEMASSRELEASESDURINGGINNASGTREVENTTABLEIII.1-1PARAMETERS USEDINEVALUATING THERADIOLOGICAL CONSEQUENCES OFASTEAMGENERATOR TUBERUPTURETABLEIII.1-2IODINEAPPEARANCf RATESINTHEREACTORCOOLANTFORA,DESIGNBASISSGTRTABLEIII.1-3REACTORCOOLANTIODINEANDNOBLEGASACTIVITYTABLEIII.1-4SHORT-TERN ATMOSPHERE DISPERSION FACTORSANDBREATHING RATESFORACCIDENTANALYSISTABLEIII.1-5ISOTOPICDATATABLEIII.1-6RESULTSOFDESIGNBASISANALYSISTABLfIII.2-1PARAMETERS USEDINEVALUATING THERADIOLOGICAL CONSEQUENCES OFTHfGINNAEVENTTABLEIII.2-2IODINEAPPEARANCE RATESINTHEREACTORCOOLANT LISTOFTABLES(Continued)

TABLEIII.2-3SHORT-TERM ATMOSPHERIC DISPERSION FACTORSANDBREATHING RATESFORACCIDENTANALYSISTABLEIII.2-4RESULTSOFGINNAEVENTANALYSIS111 LISTOFFIGURESFIGUREII.1.2-1FAULTEDSTEAMGENERATOR WATERVOLUME~~FIGUREII.1.2-2REACTORCOOLANTSYSTEMPRESSUREFIGUREII.1.2-3FAULTEDSTEAMGENERATOR PRESSUREFIGUREII.l.2-4REACTORCOOLANTAVERAGETEMPERATURE FIGUREII.1.2-5PRESSURIZER WATERVOLUMEFIGUREII.1.2-6FAULTEDSTEAMGENERATOR STEAMFLOWFIGUREII.l.2-7PRIMARY-TO-SECONDARY LEAKAGEFIGUREII.1.2-8BREAKFLOWFLASHINGFRACTIONFIGUREII.2-1CALCULATED FAULTEDSTEAMGENERATOR WATERVOLUMEDURINGTHEGINNAEVENTFIGUREII.2-2REACTORCOOLANTSYSTEMPRESSUREDURINGTHEGINNAEVENTFIGUREII.2-3FAULTEDSTEAMGENERATOR PRESSUREDURINGTHEGINNAEVENTFIGUREII.2-4CALCULATED BREAKFLOWFLASHINGFRACTIONDURINGTHEGINNAEVENTFIGUREIII.l-lBREAKFLOWFLASHINGFRACTIONFORTHEDESIGNBASISEVENTDOSEANALYSISFIGUREIII.1-2'TTENUATION FACTORFORFLASHEDCOOLANTFORTHEDESIGNBASISEVENTDOSEANALYSIS

'ISTOFFIGURES(Continued)

FIGUREIII.1-3FAULTEDSTEAMGENERATOR PARTITION FACTORFORTHEDESIGNBASISEVENTDOSEANALYSISFIGUREIII.2-1BREAKFLOWFLASHINGFRACTIONFORTHEGINNAEVENTDOSEANALYSISFIGUREIII.2-2ATTENUATION FACTORFORFLASHED.COOLANTFORTHEGINNAEVENTDOSEANALYSISFIGUREIII.2-3FAULTEDSTEAMGENERATOR PARTITION FACTORFORTHEGINNAEVENTDOSEANALYSIS I.INTRODUCTION Potential environmental consequences ofasteamgenerator tuberuptureeventattheR.E.Ginnanuclearpowerplanthavebeenevaluated toverify.thatthestandardtechnical specification limitonprimarycoolantactivityisadeuateforGinna.Massreleaseswerecalculated usingthecomputercodeLOFTRANwithconservative assumptions ofbreaksize,condenser availability, andvariousoperatorresponsetimes.Theeffectofsteamgenerator overfillandsubsequent waterreliefthroughsecondary sidereliefvalveswasalsoaddressed.

Conservative assumptions concerning coolantactivity, meteorology, andpartitioning betweenliquidandvaporphaseswereappliedtothesemassreleasestodetermine anupperboundonsiteboundaryandlowpopulation zonedoses.BestestimatemassreleasesduringtheJanuary25,1982tubefailureeventatGinna,were alsocalculated basedonanalysespresented inreference 2.Thesereleaseswereusedtoestimatepotential doseswhichcouldhaveresulted, iftheaccidenthad.occurred withcoolantactivitylimitsestablished inthe'standard technical specifications.

II.MASSRELEASES'assreleasesduringadesignbasissteamgenerator tuberuptureeventwerecalculated usingestablished fSARmethodology assumingvariousoperatorresponsetimes.ReleasesduringtheGinnaeventwerealsoestimated.

Contributions fromboththeintactandfaultedsteamgenerators wereevaluated aswellasflowtothecondenser andatmosphere.

Thesemassreleasesarepresented forvarioustimeperiodsduringtheaccident.

Theassumptions andmethodology whichwereusedtogeneratetheresults+redescribed inthefollowing sections.

II.lDesignBasisAccidentTheaccidentexaminedisthecompleteseverance ofasinglesteamgenerator tubeduringfullpoweroperation.

Thisisconsidered acondition IVevent,alimitingfault,andleadstoanincreaseinthecontamination ofthesecondary systemduetoleakageofradioactive coolantfromtheRCS.Discharge ofacti-vitytotheatmosphere mayoccurviathesteamgenerator safetyand/orpoweroperatedreliefvalves.Theconcentration ofcontaminants intheprimarysystemiscontinuously controlled tolimitsuchreleases.

II.1.1SequenceofEventsIfnormaloperation ofthevariousplantcontrolsystemsisassumed,thefol-lowingsequenceofeventsisinitiated byatuberupture:A.Thesteamgenerator blowdownliquidmonitorand/orthecondenser airejectorradiation monitorwillalarm,indicating asharpincreaseinradioactivity inthesecondary system.B.Pressurizer lowpressureandlowlevelalarmsareactuatedandchargingpumpflowincreases inanattempttomaintainpressurizer level.Onthesecondary sidesteamflow/feedwater flowmismatchoccursasfeedwater flowtotheaffectedsteamgenerator isreducedtocompensate forbreakflowtothatunit.

C.ThedecreaseinRCSpressureduetocontinued lossofreactorcoolantinventory leadstoareactortripsignalonlowpressurizer pressureorovertemperature delta-T.Plantcooldownfollowing reactortripleadstoarapiddecrease, inpressurizer levelandasafetyinjection signal,initi-"atedbylowpressurizer

pressure, followssoonafterreactortrip.Thesafetyinjection signalautomatically terminates normalfeedwater supplyandinitiates auxiliary feedwater addition.

D.Thereactortripautomatically tripstheturbineand,ifoffsitepowerisavailable, thesteamdumpvalvesopenpermitting steamdumptotheconden-ser.Intheeventofcoincident stationblackout, asassumedintheresultspresented, thesteamdumpvalvesautomatically closetoprotectthecondenser.

Thesteamgenerator pressurerapidlyincreases resulting insteamdischarge totheatmosphere throughthesteamgenerator safetyand/orpoweroperatedreliefvalves.E.Theauxiliary feedwater andboratedsafetyinjection flowprovideaheatsinkwhichabsorbsdecayheatandattenuates steamingfromthesteamgene-rators.F.Safetyinjection flowresultsinincreasing pressurizer watervolumeataratedependent upontheamountofauxiliary equipment operating.

RCSpressureeventually equilibrates atapressuregreaterthantheaffectedsteamgenerator pressurewheresafetyinjection flowmatchesbreakflow.Theoperatorisexpectedtodetermine thatasteamgenerator tuberupturehasoccurredandtoidentifyandisolatethefaultysteamgenerator onarestric-tedtimescalein'ordertominimizecontamination ofthesecondary systemandensuretermination ofradioactive release.totheatmosphere fromthefaultyunit.Sufficient indications andcontrolsareprovidedtoenabletheoperator.tocompleterecoveryprocedures fromwithinthecontrolroom.Highradiation indications orrapidlyincreasing waterlevelinanysteamgenerator providesymptomsofthefaultedsteamgenerator whichensureidentification beforethewaterlevelincreases abovethenarrowrange.Forsmallertubefailures,

samplingofthesteamgenerators forhighradiation mayberequiredforpositiveidentification.

However,inthatcaseadditional timewouldbeavailable beforewaterlevelincreases outofnarrowrange.Onceidentified, thefaultedsteamgenerator isisolatedfromtheintactsteamgenerators tominimizeactivityreleasesandasanecessary steptowardestab-lishingapressuredifferential betweentheintactandfaultedsteamgenera-tors.TheMai'nSteamline Isolation Valves(NSIV)providethiscapability.

IntheeventofafailureoftheMISVforthefaultedsteamgenerator, theNSIVfortheintactsteamgenerator andtheturbinestopvalveensurearedundant meansofisolation.

Auxiliary feedwater flowisterminated tothefaultedunitinanattempttocontrolsteamgenerator inventory.

Thereactorcoolanttemperature isreducedtoestablish aminimumof50Fsubcooling marginattherupturedsteamgenerator pressurebydumpingsteamfromtheintactsteamgenerator.

Thisassuresthattheprimarysystemwillremainsubcooled following depressurization tothefaultedsteamgenerator pressureinsubsequent steps.Ifthecondenser isavailable, thenormalsteamdumpsystemisusedforthiscooldown.

Isolation ofthefaultedsteamgenera-torensuresthatpressureinthatunitwillnotdecreasesignificantly.

Ifthecondenser isunavailable oriftheMSIVforthefaultedsteamgenerator fails,theatmospheric reliefvalveontheintactsteamgenerator providesanalternative meansofcoolingthereactorcoolantsystem.Theprimarypressureisreducedtoavalueequaltothefaultedsteamgenera-torpressureusingnormalpressurizer spray.Thisactionrestorespressurizer levelassafetyinjection flowinexcessofbreakflowreplacescondensed steaminthepressurizer, andmomentarily stopsprimary-to-secondary leakage.Ifnormalsprayisnotavailable, thepressurizer PORVsandauxiliary spraysystemprovideredundant meansofdepressurizing thereactorcoolantsystem.lTermination ofsafetyinjection flowisrequiredtoensurethatbreakflowisnotreinitiated.

Previousoperatoractionsaredesignedtoestablish suffi-cientindications ofadequateprimarycoolantinventory andheatremovalsothatcorecoolingwillnotbecompromised asaresultofSItermination.

Thissequenceofrecoveryactionsensuresearlytermination ofprimary-to-secondary leakagewithorwithoutoffsitepoweravailable.

Thetimerequiredtocompletetheseactionsareeventspecificsincesmallerbreaksmaybemoredifficult todetect.Intheseanalyses, operatoractiontimeshavebeentreatedparametrically, rangingfrom30minutestoamaximumof60minutestocompletethekeyrecoverysequence.

II.1.2MethodofAnalysisMassandenergybalancecalculations wereperformed usingLOFTRANtodetermine primary-to-secondary massleakageandtheamountofsteamventedfrom'each ofthesteamgenerators priortoterminating safetyinjection.

Inestimating themassreleasesduringrecovery, thefollowing assumptions weremade:A.Reactortripoccursautomatically asaresultoflowpressurizer pressureorovertemperature delta-T.Lossofoffsitepoweroccursatreactortrip.B.Following theinitiation ofthesafetyinjection signal,allsafetyinjec-tionpumpsareactuated.

Flowfromthenormalchargingpumpsisnotcon-sideredsinceitisautomatically terminated onasafetyinjection signal.C.Thesecondary sidepressureisassumedtobecontrolled atthesafetyvalvepressurefollowing reactortrip.Thisisconsistent withlossofoffsitepower.D.Auxiliary feedwater flowisassumedthrottled tomatchsteamflowinallsteamgenerators tocontrolsteamgenerator level.Minimumauxiliary feedwater capacityisassumed.Thisresultsinincreased steamingfromthesteamgenerators.

E.Individual operatoractionsarenotexplicitly modeledintheanalysespresented.

However,itisassumedthattheoperatorcompletes therecoverysequenceonarestricted timescale.Thistimeistreatedpara-metrically.

F.Forcaseswheresteamgenerator overfilloccurs,waterrelieffromthefaultedsteamgenerator totheatmosphere isassumedequaltoanyaddi-tionalprimary-to-secondary leakageafteroverfilloccurs.Steamline volumeisnotconsidered incalculating thetimeofsteamgenerator over-fil1.Priortoreactortripsteamisassumedtobereleasedtothecondenser fromthefaultedandintactsteamgenerators.

Steamfromallsteamgenerators isdumpedtotheatmosphere afterreactortripsincethecondenser isunavailable asaresultofstationblackout.

Extendedsteamreleasecalculations, i.e.afterbreakflowhasbeentermina-ted,reflectexpectedoperatoractionsasdescribed intheMestinghouse OwnersGroup'sEmergency ResponseGuidelines

.Following isolation ofthefaultedsteamgenerator, itisassumedthatsteamisdumpedfromtheintactsteamgenerator toreducetheRCStemperature to50'Fbelowno-loadTavg.Fromtwotoeighthoursaftertubefailure,theRCScoolanttemperature isreducedtoResidualHeatRemovalSystem(RHRS)operating conditions viaaddi-.tionalsteamingfromtheintactsteamgenerator.

Furtherplantcooldowntocoldshutdown, iscompleted withtheRHRS.Ifsteamgenerator overfilldoesnotoccur,thefaultedsteamgenerator isdepressurized byreleasing steamfromthatsteamgenerator totheatmosphere.

Analternate cooldownmethod,suchasbackfillintotheRCS,isconsidered ifthefaultedsteamgenerator fillswithwater.Inthatcaseadditional steamingoccursfromtheintactsteamgenerator.

Theextendedsteamandfeedwater flowsaredetermined fromamassandenergybalanceincluding decayheat,metalheat,energyfromoneoperating reactorcoolantpump,andsensibleenergyofthefluidintheRCSandsteamgenerators.

Thesequenceofeventsforthedesignbasisaccidentarepresented inTableII.1.2-1.Theprimary-to-secondary carryoverandsteamandfeedwater flowsassociated witheachofthesteamgenerators areprovidedinTablesII.1.2-2andII.1.2-3forrecoverytimesof30and60minutes,respectively.

Sinceindividual operatoractionswerenotmodelled, thesystemresponseisthesameforbothcases.Mith30minuteoperatoractiontoterminate breakflow, TABLEII.1.2-1DESIGNBASISACCIDENTSEQUENCEOFEVENTSEventManual(0)Time(Sec)Automatic (A)30MinRecovery60MinRecoveryTubeFailureReactorTripCondenser LostSISignalFeedwater Isolation AFWInitiation AFWThrottled toFaul.tedSGIsolation ofFaultedSGSteamDumpRCSDepressurization SGOverfillSITerminated BreakFlowTerminated RHRCooling27271271341871871800(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-TTBRK TTBRK-22-TRHRRupturedSG:-Condenser

-Atmosphere

-Feedwater 278200.0326050.0326400.00.00.00.00.02148021480IntactSG:-Condenser

-Atmosphere

-Feedwater 273800.0371700.023050133700.01446502062000.0470000487600BreakFlow33251006480.00.0TTRIP=27.0sec=TimeofreactortripTTBRK=1800,sec=Timetoterminate breakflowTRHR=28800sec=Timetoestablish RHRcooling ITABLEII.1.2-3MASSRELEASESDURINGADESIGNBASISSGTR:60MINUTERECOVERYFlow(ibm)TimePeriod0-TTRIPTTRIP-TMSEP-TSGOF-TTBRK-22-TRHRTMSEPTSGOFTTBRKRupturedSG:-Condenser 27820-Atmosphere 0.0-Feedwater 326050.0335700.00.048300.00.00.00.00.0431710.00.00.00.0IntactSG:-Condenser 27380-Atmosphere 0.0-Feedwater 371700.023370137000.0139013900.00.00.039067970501100380129600518700BreakFlow332510774248070431710.00.0TTRIP=27.0sec=TimeTMSEP=1930sec=TimeTSGOF=2810sec=TimeTTBRK=3600sec=TimeofreactortriptofillSGtomoistureseparators tofillSG(w/osteamline volume)toterminate breakflowTRHR=28800sec=Timetoestablish RHRcooling9 liquidlevelinfaultedsteamgenerator remainsbelowthebottomofthemois-tureseparator, FigureII.1.2-1.

Hence,forthiscase,partitioning betweenthevaporandliquidphaseseffectively reducesradiological releasesforthedurationoftheaccident.

Fordelayedrecovery, case2,themoisturesepara-torbeginstofloodat32minutes.Thefaultedsteamgenerator iscompletely filledby47minutes.Duringthistime,liquidentrainment withinthesteamflowwouldincreasesothattheeffectiveness ofpartitioning wouldbereduced.Beyond47minutes,i.e.steamgenerator

overfill, waterrelieffromthefaultedsteamgenerator isassumedequaltobreakflow.Thefollowing isalistoffiguresofpertinent timedependent parameters:

FIGUREII.1.2-1FAULTEDSGWATERVOLUMEFIGUREII;1.2-2REACTORCOOLANTSYSTEMPRESSUREFIGUREII.1.2-3FAULTEDSGPRESSUREFIGUREII.1.2-4REACTORCOOLANTSYSTEMTEMPERATURE FIGUREII.1.2-5PRESSURIZER WATER.VOLUMEFIGUREII.1.2-6FAULTEDSGSTEAMFLOWFIGUREII.l.2-7BREAKFLOWFIGUREII.1.2-8BREAKFLOWFLASHINGFRACTIONII.2GINNAEVENTAdetailedthermal-hydraulic analysisoftheGinnaeventisdescribed inreference 2.Theresultsofthatanalysisformthebasisforthecalculation ofthepotential environmental consequences.

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)lERATOR HATERVOLU)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.

FAULTEDSTEAHGENERATOR PRESSURE.

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.

PRESSURIZER HATERVOLUtlE.15

0.20000.17500.1500OQ0.12500.1000CD0.0750CD0.05000.02500.0CICDCD8CDCDmTIME(HIM)CDCDCDCDlACDCDCDCOFIGUREII.1.2-6.

FAULTEDSTEANGENERATOR STEANFLOW.16 150.00125.00100.00l5.000~50.00025.0000.0CDCDCDCDAJCDmTIME(MIN)CDCDCDCDCDIClCD0EDFIGUREII.l.2-7.PRIl1ARY-TQ-SECONDARY LEANGE.17

0.20000.17500.15000.1250I-0.10000.05000.0250'0.0CDCDCDCDflJCDmTIME(MIN)CDCDCDCDCDVlCDCDCD\FIGUREII.1-2-8.

BREAKFLOllFLASHINGFRACTION.

18 Jt TABLEII.2-1GINNASE()UENCE OFEVENTSEventManual(0)Automatic (A)ActualTime(sec)SimulatedTubeFailureReactorTripCondenser Lost'ISignalFeedwater Isolation AFWInitiated AFWThrottled toFaultedSGIsolation ofFaultedSGSteamDumpRCSDepressurization SGOverfillSITerminated BreakFlowTerminated RHRCoolingAAA00000.000182450019019222041089077027004310108007758001824500198198..2394105305302700313043101080077580includessteamline volume19

eventdescribed insectionII.l.l.Breakflowinexcessofnormalcharging-flowdepletedreactorcoolantinventory andeventually resultedinreactortriponlowpressurizer pressure.

Asafetyinjection signalfollowedsoonaftertrip.Normalfeedwater flowwasautomatically terminated onthesafetyinjection signalandauxiliary feedwater flowwasinitiated.

Thesteamdumpsystemoperatedtocontrolsteamgene-ratorpressurebelowthesafetyvalvesetpointandestablish no-loadreactorcoolanttemperature.

Auxiliary feedwater and'afety injection flowsabsorbeddecayheatandtemporarily stoppedsteamreleasesfromthesteamgenerators.

Emergency recoveryactionswerequicklyinitiated tomitigatetheconsequences oftheaccident.

Pre-tripsymptomsofthefaultedsteamgenerator, including steamflow/feed flowmismatchandsteamgenerator leveldeviation alarms,providedtentative indications ofthefaultedsteamgenerator whichwerecon-firmedsoonafterreactortripbyrapidlyincreasing steamgenerator levelandhighradiation indications.

Auxiliary feedwater flowwasreducedtothefaultedunitinanattempttocontrolinventory.

Isolation ofthefaultedsteamgenerator wascompleted within15minutesoftubefailurebyclosingtheassociated MSIV.Continued auxiliary feedwater flowtotheintactsteamgene-ratoreffectively reducedtheprimarysystemtemperature toestablish 50Fsubcooling margin.Normalspraywasunavailable sincereactorcoolantpumpsweremanuallytrippedsoonafterreactortripasdirectedbyemergency proce-dures.Consequently, onepressurizer PORVwasusedasanalternative meansofdepressurizing theprimarysystemtorestorepressurizer levelandreducebreakflow.Thiswascompleted within45minutes.Safetyinjection flowwassubsequently terminated after72minutes.Continued chargingflowandreini-tiationofsafetyinjection flowresultedinadditional primary-to-secondary leakageuntilapproximately 3hrsaftertubefailure.MassreleasesduringtheGinnaeventarepresented inTableII.2-2.LOFTRANresultsindicatethatthefaultedsteamgenerator andsteamline filledwithwaterafterapproximately 52minutes,FigureII.2-1.Beyondthistimewaterrelieffromthefaultedsteamgenerator wasassumedequaltoanyadditional primary-to-secondary leakage.Themeasuredprimaryandfaultedsteamgenera-torpressures andcalculated breakflowflashingfractionduringtheaccident20

TABLEII.2-2BESTESTIMATEMASSRELEASESDURINGGINNASGTREVENTFlow(ibm)TimePeriod0-TTRIPTTRIP-TMSEP-TSGOF*-22-TTBRKTTBRK-TMSEPTSGOF*TRHRFaultedSG:-Condenser 162100-Atmosphere 0-Feedwater 16340016900046800013044200105684,0~0IntactSG:-Condenser 160100-Atmosphere

.0-Feedwater 1717002880025200145000.02387052300089700054743530080978387983292BreakFlow103005433099170130442105684TTRIP=182.0sec=TimeofreactortripTMSEP=1335sec=TimetofillSGtomoistureseparator TSGOF=2192sec=TimetofillSGTSGOF*=3131sec=TimetofillSGandsteamline TTBRK=10200sec=Timetoterminate breakflowTRHR=77580sec=Timetoestablish RHRcooling21 7000.06000.0S.G.ANDSTEAr>LINE VOLUWE5000.0S.G.VOLUtlEF000.0I~)3000.0I2000.01000.00.0CDCDCDCDIAAJCDCDCDCDCDi/IPeaCDCDCDTlHE<HlN)CDCDV1AJCDCD"tAOOG)D~~AO(QFIGUREII.2-1.CALCULATED FAULTEDSTEAHGENERATOR MATERVOLUt1EDURINGTHEGINNAEVENT.22 2300.02250.02000.01750.01500.0C1250.0GGGG1000.0,0.GGG750.00500.00300.00CIEDCDItlAJC)EDIAClDOO~~If)Q(oTlME(MlN)FIGUREII22REACTORCOOLANTSYSTEi~'1 PRESSUREDURIHGTHEGIHHAEYEHT.23 1200.01000.0cc800.00~600.00~F00.00CL200.000.0ClClClClCllAAJClCDClClCDClCII/ITIME(MIN)ClCDCDClCDClIllAJCDClIClOOOO~~IOOFIGUREII.2-3.FAULTEDSTEAhGENERATOR PRESSUREDURINGTHEGINNAEVENT.

0.20000i)50005000.025000CITENTtNttllFIGUREII.2-4.CALCULATED BREAKFLOliFLASHI(HG FRACTIONDURINGT)lEGIN(iAEVEiPT.25 arepresented inFiguresII.2-2thruII.2-4.Theseresultsshowthatapproxi-mately236,000ibmofmasswerereleasedafterthefaultedsteamgenerator andsteamline wascalculated tofillwithwater.Approximately 130,000ibmofthiswerereleasedinthefirst2hrs.Steamflowtocondenser wasterminated atapproximately 75minutes.Massreleaseswereterminated whentheRHRSwasplacedinserviceafter21.5hrs.\26

III.ENVIRONMENTAL CONSEQUENCES ANALYSISIntroduc.ti onFortheevaluation oftheradiological consequences ofasteamgenerator tuberupture,itisassumedthatthereactorhasbeenopertingwithasmallpercentofdefective fuelforsufficient timetoestablish equilibrium concentrations ofradionuclides inthereactorcoolant.Hence,radionuclides fromthe'rimarycoolantenterthesteamgenerator, viatherupturedtube,andarereleasedtotheatmosphere throughthesteamgenerator safetyorpoweroperatedreliefvalves.Theradioactivity releasedtotheenvironment, duetoaSGTR,dependsuponprimaryandsecondary coolantactivity, iodinespikingeffects,primarytosecondary breakflow,timedependent breakflowflashingfractions, timedependent scrubbing offlashedactivity, partitioning oftheactivityfromthenonflashedfractionofthebre'akflowbetweenthesteamgenerator liquidandsteamandthemassoffluiddischarged totheenvironment.

Alloftheseparameters wereconservatively evaluated foradesignbasistubefailure,i.e.doubleendedruptureofasingletube,asdescribed inSectionII.1.ThemassreleasesduringtheGinnaeventwerealsoestimated inSectionII.2.Theenvironmental consequences attheseeventswerecalculated andarediscussed inthefollowing sections.

III.lDESIGNBASESANALYTICAL ASSUMPTIONS Themajorassumptions andparameters usedintheanalysisareitemizedinTableII.l-landaresummarized below.27

SourceTermCalculations Theconcentrations ofnuclidesintheprimaryandsecondary system,priortotheaccidentaredetermined asfollows:a.Theiodineconcentrations inthereactorcoolantwillbebaseduponpreaccident andaccidentinitiated iodinespikes.i.Preaccident Spike-Areactortransient hasoccuredpriortotheSGTRandhasraisedtheprimarycoolantiodineconcentration to60pCi/gramofDoseEquivalent I-131.ii.AccidentInitiated Spike-Thereactortriporprimarysystemdepressurization associated withtheSGTRcreatesaniodinespikeintheprimarysystemwhichincreases theiodinereleaseratefromthefueltotheprimarycoolanttoavalue500timesgreaterthanthereleaseratecorresponding tothemaximumequilibrium primarysystemiodineconcentration oflpCi/gram ofDoseEquivalent (D.E.)I-131.Thedurationofthespikeisassumedtobe4hours.Iodineappearance ratesinthereactorcoolantarepresented inTableIII.1-2.Dosesarecalculated forbothcasesofspiking.b.Thenoblegasactivityinthereactorcoolantisbasedon1percentfueldefects,asprovidedinTableIII.1-3.Theassumption of1percentfueldefectsforthecalculation ofnoblegasactivity, isconservative, sincelpCi/gram D.E.I-131and1percentdefectscannotexistsimultaneously.

Iodineactivitybasedon1percentdefectswouldbegreaterthantwicetheStandardTechnical Specification limit.c.Thesecondary coolantactivityisbasedontheO.E.of0.1pCi/gramofI-131.d.Iodineattherupturepointisassumedtoconsistof99.9percentelemental and0.1percentorganiciodine.28

'IDoseCalculations Thefollowing assumptions andparameters areusedtocalculate theactivityreleasedandtheoffsitedosesfollowing aSGTR.a.Themassofreactorcoolantdischarged intothesecondary systemthroughtheruptureandthemassofsteamand/orwaterreleasedfromtheintactandfaultedsteamgenerators, totheenvironment ispresented inTablesII.1.2-2and3.b.Thetimedependent fractionofrupture'flow thatflashestosteamandisimmediately releasedtotheenvironment isshowninFigureIII-l-l.c.Thetimedependent elemental iodineattenuation factorforretention ofatomizedprimarydropletsbythemoistureseparators anddryersandforscrubbing ofsteambubblesastheyrisefromtheleaksitetothewatersurfaceispresented inFigureIII.1-2.Retention bymoistureseparators andscrubbing areeffectedbydifferential pressure(aP)acrosstherupturedtubeandwaterlevel.,Specifically forthefirst4minutesdPisassumedtobe.high(>1000psi)andwaterlevellow(justabovetopoftubebundle).Forthisperiod,neitherretention norscrubbing isassumedandtheoverallfactoris1.0.Fortimesgreaterthan4minutes,theaPdecreases toapproximately 300psiandremainsconstant.

fortimesgreaterthan4butlessthan32minutes,retention bytheseparators isconstantandatamaximum.At32minutestheseparators begintofloodandat47minutesthegenerator isfilled.Retention bytheseparators decreases fromthemaximumat32minutestozeroat47minutes.Scrubbing increases withrisingwaterlevel.d-The1gpmprimarytosecondary leakisassumedtobesplitevenlybetweenthesteamgenerators.

29

e.Allnoblegasactivityin.thereactorcoolantwhichistransported tothesecondary systemviathetuberuptureandtheprimary-to-secondary leakageisassumedtobeimmediately releasedtotheenvironment.

f.CaseIassumes30minuteoperatoractiontoteminatebreakflow.TheliquidlevelinthefaultedSGremainsbelowthemoistureseparator.

Case2assumes60minuteoperatoraction.Themoistureseparator beginstofloodat32minutesandthegenerator isfilledat47minutes.g.Theelemental iodinepartition factorbetweentheliquidandsteamoftheintactSGisassumedtobe100.Thetimedependent partition factorforthefaultedSGispresented inFigureIII.1-3.h.Offsitepowerislostfollowing reactortrip.i..Eighthoursafter.theaccident, theRHRsystemisassumedtobeinopera'tion

'tocooldowntheplant.Thus,noadditional steamreleaseisassumed.j.Neitherradioactive decay,duringreleaseandtransport, norground~~~~~~~~deposition ofactivitywasconsidered.

k.Short-term atmospheric dispersion factors(x/g's)foraccidentanalysisandbreathing ratesareprovidedinTableIII.1-4.1.Decayconstants, averagebetaandgammaenergiesandthyroiddoseconversion factorsarepresented inTableIII.1-5.30

OFFSITETHYROIDDOSECALCULATION MODELOffsitethyroiddosesarecalculated usingtheequationwhereTh(IAR)integrated activityofisotopeireleased*

duringthetimeintervaljinCiandbreathing rateduringtimeintervaljinmeter/secondoffsiteatmospheric dispersion factorduringtimeintervaljinsecond/meter (DCF).thyroiddoseconversion factorviainhalation forisotopeiinrem/Cithyroiddoseviainhalation inremsOFFSITETOTAL-BODY DOSECALCULATIONAL MODELAssumingasemi-infinite cloudofbetaandgammaemitters, offsitetotal-body dosesarecalculated usingtheequation:

DTB025Z5;g(IAR);.(XID).ij31 whereIntegrated activityofisotopeireleased*

duringthejtimeintervalinCiandoffsiteatmospheric dispersion factorduringtimeintervaljinsecond/meter E-conservatively assumedtobethesumofthebetaandgammaenergyfortheiisotopeinmev/dis.'TBtotal-body doseinrems*Nocreditistakenforclouddepletion bygrounddeposition.

andradioactive decayduringtransport totheexclusion areaboundaryortotheouterboundaryofthelow-.population zone.ResultsThyroidandTotal-Body dosesattheSiteBoundaryandLowPopulation Zonearepresented inTableIII.1-6.Alldosesarewithintheguidelines of10CFR100.

32 I

TABLEIII.1-1PARAMETERS USEDINEVALUATING THERADIOLOGICAL CONSEQUENCES OFASTEANGENERATOR TUBERUPTURE(SGTR)SourceDataa.Corepowerlevel,MWtb.Steamgenerator tubeleakage,gpmc.Reactor-coolantiodineactivity:152011..Accident Initiated SpikeInitialactivityequaltothedoseequivalent of1.0pCi/gmofI-131withanassumediodinespikethatincreases therateofiodinereleaseintothereactorcoolantbyafactorof500.SeeTablesIII.1-2and3.2.Pre-Accident SpikeAnassumedpre-accident iodinespike,whichhasresultedinthedoseequivalent of60pCi/gmofI-131inthereactorcoolant.d.Reactorcoolantnoblegasactivity, bothcasesBasedon1-percent failedIfuelasprovidedinTableIII.1-3.33 TABLEIII.1-1[Sheet2)e.Secondary systeminitialactivityDoseequivalent ofO.lpCi/gmofI-131f.Reactorcoolantmass,gramsg.Steamgenerator mass(each),grams1.27x103.39x10h.OffsitepowerLosti.Primary-to-secondary

!1eakagedurationj.Speciesofiodine99.9percentelemental 0.1percentorganicCase1-30minCase2-60minII.Atmospheric Dispersion FactorsIII.ActivigReleaseDataSeeTableIII.1-4a.Faultedsteamgenerator 1.Reactorcoolantdischarged tosteamgenerator, lbs.SeeTableIII.1.2-2 or32.Flashedreactorcoolant,fractionSeeFigureIII.1-13.Iodineattenuation factorforflashedfractionofreactorcoolantSeeFigureIII.1-2I34 TABLEIII.1-1(Sheet3)4.Totalsteamrelease,lbsSeeTableIII.1.2-2 or35.IodinepartitionfactorforthenonflashedfractionofreactorcoolantthatmixeswiththeinitialiodineactivityinthesteamgeneratorSeeFigureIII.1-3t6.LocationoftuberuptureTopofBundleb.Intactsteamgenerator 1.Primary-to-secondary 1ca/age,1bs/hr1802.Flashedreactor.coolant,fraction3.Totalsteamrelease,lbsSeeTableIII.1.2-2 or34.Iodinepartition factor1005.Isolation time,hrs35 TABLEIII.1-2IODINEAPPEARANCE RATESINTHEREACTORCOOLANT{CURIES/SECOND)

FORADESIGNBASISSGTRI-131I-132I-133I-134I-135EquilibriumAppearance RatesduetoTechnical Specification Fueldefects1.88x104.44x103.48x106.14x104.68x10Appearance RatesduetoanIodineSpike-500X equilibriumrates0.942.221.743.072.34 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*Secondary coolantiodineactivityisbasedon0.1pCi/gramofDoseEquivalent I-131andistherefore 10percentofthesevalues.37 TABLEIII.1-4'HORT-TERN ATt10SPHERIC DISPERSION FACTORSANDBREATHING RATESFORACCIDENTANALYSISTimeSiteBoundary~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-880.1580.00000735 0.5470.2480.160.00230.793,2.210.250.2511.330.2539

TABLE111.1-6RESULTSOFDESIGNBASISANALYSISDoses(Rem)Case1Case21.AccidentInitiated IodineSpikeSiteboundary0-2hr.)ThyroidTota1-body2.90.3191.50.5LowPopulation Zone(0-8hr)ThyroidTota1-body0.190.025.70.032.Pre-Accident IodineSikeSiteboundary(0-2hr)ThyroidTota1-body22.30.312730.5LowPopulation Zone(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)ATTENUATION FACTORFORFLASHEOREACTORCOOLANT42 l0050O40a30020l0NORMALLEVEL3047TOBOTTOMS.G.OFMOISTUREFILLEDSEP.TIME(MINUTES)

FAULTEDS.G.PARTITION FACTORFORNONFLASHEDREACTORCOOLANT43

III.2BestEstimateAnalytical Assumptions Themajorassumptions andparameters usedintheanalysisareitemizedinfaoleIII.2-1andaresummarized below.SourceTermCalculations

)heconcentrations ofnuclidesintheprimaryandsecondary system,priortotheaccidentaredetermined asfollows:a.Theiodineconcentrations inthereactorcoolantwillbebaseduponpreaccident andaccidentinitiated iodinespikes.L~i.Preaccident Spike-Areactortransient hasoccurredpriortotheSGTRandhasraisedtheprimarycoolantiodineconcentration to8pCi/gramofDoseEquivalent I-131.(Thebasisforthespikingfactorsispresented inRef.9.)ii.AccidentInitiated Spike-Thereactortriporprimarysystemdepressurization associated withtheSGTRcreatesaniodinespikeintheprimarysystemwhichincreases theiodinereleaseratefromthetueltotheprimarycoolanttoavalue30L~timesgreaterthanthereleaseratecorresponding tothemaximumequilibrium primarysystemiodine.concentration oflpCi/gram ofDoseEquivalent (O.E.)1-13l.Thedurationoftnespikeisassumedtobe4hours.Iodineappearance ratesinthereactorcoolantarepresented inTable2.Dosesarecalculated forbothcasesofspiking.b.Thenoblegasactivityinthereactorcoolantisbasedon1-percent fueldefects,asprovidedinTable3ofPartIII.l.c.Tnesecondary coolantactivityisbasedontheO.E.ofO.luCi/gramofI-131.d.Iodineattherupturepointisassumedtoconsistof100percentelemental iodine.

Theassumption of1-percent fueldefectsforthecalculation ofnoblegasactivityisconservative sincelgCi/gram D.E.I-131andIpercentdefectscannotexistsimultaneously.

IodineactivitybasedonIpercentdefectswouldbegreaterthantwicetheTechnical Specification limit.DoseCalculations Thefollowing assumptions andparameters areusedtocalculate theactivityreleasedandtheoffsitedosesfollowing aSGTR.a.Themassofreactorcoolantdischarged intothesecondary systemthroughtheruptureandthemassofsteamand/orwaterreleasedfromtheintactandfaultedsteamgenerators, totheenvironment ispresented inTableIII.2-2.b.Thetimedependent fractionofruptureflowthatflashestosteamandisimmediately releasedtotheenvironment isshowninFigureIII.2-1.c.Thetimedependent elemental iodineattenuation factorforretention ofatomizedprimarydropletsbythemoistureseparators anddryersandforscrubbing ofsteambubblesastheyrisefromtheleaksitetothewatersurfaceispresented inFigureIII.2-2.Retention bymoistureseparators andscrubbung areeffectedbydifferential pressure(aP)acrosstherupturedtubeandwaterlevel.Specifically forthefirst5minutessPisassumedtobehigh(550psi)andwaterlevellow(topoftubebundle).Forthisperiod,retention andscrubbing areassumedandtheoverallfactoris1.45.Fortimesgreaterthan5minutestheaPdecreases toapproximately 450psiandisassumedconstantforthedurationoftheflashingperiod.fortimesgreaterthan5butlessthan22minutes,retention bytheseparators isassumedconstantandatamaximum.At22minutestheseparators begintofloodandat52minutesthegenerator andsteamlinearefilled.Retention bytheseparators decreases fromthemaximumat5minutesto.zeroat36minutes.Scruobing increases withrisingwaterlevel..

d.TheIgpmprimarytosecondary leakisassumedtobesplitevenlybetweenthesteamgenerators.

e.Allnoblegasactivityinthereactorcoolantwhichis"transported tothesecondary systemviathetuberuptureandtheprimary-to-secondary leakageisassumedtobeimmediately releasedtotheenvironment.

f.Themoistureseparator beginstofloodat22minutesandthegenerator andsteamlinearefilledat52minutes.g.Theelemental iodinepartition factorbetweentheliquidandsteamoftheintactSGisassumedtobe5000.Thetimedependent partition factorforthefaultedSGispresented inFigureIII.2-3.h.Offsitepowerisavailable.

i.21.5hoursaftertheaccident, theRHRsystemisassumedtobeinopera-tiontocooldowntheplant.Thus,noadditional steamreleaseisassumed.~~~~~~j.Neitherradioactive decay,duringreleaseandtransport, norgrounddeposition ofactivitywasconsidered.

k.Short-term atmospheric dispersion factors(X/g's)foraccidentanalysisandbreathing ratesareprovidedinTableIII.2-3.l.Decayconstants, averagebetaandgammaenergiesandthyroiddoseconver-sionfactorsarepresented inTable5ofPartIII.1.OffsiteThyroidandTotal-8ody DoseCalculational ModelsSeePartIII.1ResultsThyroidandtotal-body dosesatthesiteboundaryandlowpopulation zonearepresented inTableIII.2-4.Alldosesarewithintheguidelines of10CFR100.

46

TABLEIII.2-1PARAMETERS USEDINTHEBESTESTIMATEEVALUATION THERADIOLOGICAL CONSEQUENCES OFTHEGINNAEVENTI.SourceDataa.Corepower1evel,MNtb.Steamgenerator tube1eakage,gpmc.Reactorcoolantiodineactivity:152011.AccidentInitiated SpikeInitialactivityequaltothedoseequivalent of1.0pCi/gmofI-131withanassumediodinespikethatincreases therateofiodinereleaseintothereactorcoolantbyafactorof30.SeeTablesIII.2-2,III.1-3.2.Pre-AccidentSpikeAnassumedpre-accident iodinespike,whichhasresultedinthedoseequivalent of8pCi/gmofI-131inthereactorcoolant.d.ReactorcoolantnoblegasactiviBasedon1-percent failedfuelAsprovidedinTableIII.1-3ofSectionIII.1e.Secondary systeminitialactivityf.Reactorcoolantmass,gramsg.Steamgenerator mass(each)gramsh.OffsitepowerDoseequivalent of0.1pCi/gmofI-131.1.27x1083.39x10Available 47 TABLEIII.2-1(Continued)

Primary-to-secondary leakagedurationj.Speciesofiodine185min100percentelemental II.Atmospheric Dispersion FactorsSeeTableIII.2-3III.ActivityReleaseDataa.Faultedsteamgenerator 1.Reactorcoolantdis-chargedtosteamgenerator, lbs.SeeTableII.2-22.Flashedreactorcoolant,fraction3.Iodineattenuation factorforflashedfractionofreactorcoolant4.Steamandwaterreleases, lbs5.Iodinepartition factorforthenonflashedfractionofreactorcoolantthatmixeswiththeinitialiodineactiviginthesteamgenerator 6.LocationoftuberuptureSeeFigureIII.2-1SeeFigureIII.2-2SeeTableII.2-2SeeFigureIII.2-34inchesabovetubesheetb.Intactsteamgenerator 1.Primary-to-secondary leakage,lbs/hr180

TABLEIII.2-1(Continued) 2.Flashedreactorcoolant3.4~fractionTotalsteamrelease,lbsIodinepartition factorIsolationtime,hrsSeeTableII.2-2500021.55c.Condenser 1.Iodinepartition factor500049

TABLEIII.2-2IODINEAPPEARANCE RATESINTHEREACTORCOOLANT(CURIES/SECOND)

I-131I-133I-134I-135EquilibriumAppearance RatesduetoTechnical Specification fuelDefects1.88x104.44x103.48x106.14x104.68x10Appearance RatesduetoanIodineSpike-30X equilibriumrates5.64x101.33x101.04x101.84x101.4x10 TABLEIII.2-3SHORT-TERM ATMOSPHERIC DISPERSION FACTORSAND8REATHINGRATESFORACCIDEWTANALYSESTime(hours)SiteBoundaryx/q(Sec/m)LowPopulationZonex/g(Sec/m)Breathing Rate(m/sec)0-24.8x103.47x100-83x103.47x108-243x101.75x10Note:x/g'sare10percentoftheR.G.1.145values.51

TABLEIII.2-4RESULTSOFGINNAEVENTANALYSES1.AccidentInitiated IodineSpikeDoses(Rem)Siteboundary(0-2hr)ThyroidTota1-body2.90.5LowPopulation Zone(0-8hr)ThyroidTotal-body1.40.0482.PreAccidentSikeSiteboundary(0-2hr)ThyroidTota1-body8.50.5LowPopulation Zone(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)30ATTENUATION FACTORFORFLASHEDREACTORCOOLANTFORTHEGlNNAEVENT54

5000a:1000OfOf-.F-100IIIIIIIIIIIIIIIIIIIIIIIII10ZO3060TIMEIMlNUTES)FAULTEDS.G.PARTIT10N FACTORFOR'HEGINNAEVENT,I55

IV.SUMMARYANDCONCLUSIONS Thepotential environmental consequences ofasteamgenerator tubefailureattheR.E.Ginnanuclearpowerplantwereevaluated inordertodemonstrate

~~~~~~~thattheStandardTechnical Specifications limitonprimarycoolantactivityisacceptable.

Themassreleasesduringadesignbasisevent,i.e.adoubleendedruptureofasingletube,wereconservatively calculated usingthecom-putercodeLOFTRAN.Fortheseanalyses, thesequenceofrecoveryactionsinitiated bythetubefailurewereassumedtobecompleted onarestricted timescale.Twocaseswereconsidered:

a)30minuterecovery, andb)60min'uterecovery.

Theeffectofsteamgenerator overfil1onradiological

'eleaseswasalsoconsidered.

Massreleasesduringthedesignbasiseventwereusedwithconservative assumptions ofcoolantactivity, meteorology, andattenuation toestimateanupperboundofsiteboundaryandlowpopulation zoneexposures.

ThemassreleasesfromtheJanuary25,1982steamgenerator tubefailureatGinnawerealsocalculated fromresultspresented inreference 2.ThesereleaseswereusedwiththeStandardTechnical Specification limitoninitialcoolantactivityandamorerealistic meteorology toevaluatepotential dosesonamorerealistic basis.Resultsofthedesignbasisanalysesindicatethattheconservative siteboundaryandlowpopulation zoneexposures fromasteamgenerator tubefailurearewithin10CFR100limitations withtheStandardTechnical Specification limitoninitialcoolantactivity.

Estimates ofthepotential radiological releasesfromamorerealistic eventwiththesameinitialcoolantactivitydemonstrate thatthedesignbasisanalysisisveryconservative.

Conse-quently,theStandardTechnical Specification limitoncoolantactivityaresufficient toensurethattheenvironmental consequences ofasteamgenerator tubefailureattheR.E.Ginnaplantwillbewithinacceptable limits.56 REFERENCES 1.L.A.Campbell, "LOFTRANCODEDESCRIPTION",

WCAP-7878 Rev.3,January(1977).2.E.C.Volpenhein, "ANALYSIS OFPLANTRESPONSEDURINGJANUARY26,1982STEANGENERATOR TUBEFAILUREATTHER.E.GINNANUCLEARPOWERPLANT",Westinghouse ElectricCo.,October(1982).3.WESTINGHOUSE OWNERSGROUPEMERGENCY RESPONSEGUIDELINES

SElfINAR, September 1981.4.NRCStandardReviewPlan15.6-3,Rev.2,"Radiological Consequences ofaSteamGenerator TubeFailure",

Ju'ly,1981.5.NRCNUREG-0409, "IodineBehaviorinaPWRCoolingSystemFollowing aPostulated SteamGenerator TubeRuptureAccident",

Postma,A.K.,Tam,P.S.,Jan.1978.6-NRCRegulatory Guide1.145,"Atmospheric Dispersion ModelsforPotential

.AccidentConsequence Assessments atNuclearPowerPlants",August,1979.7.-NRC.Regulatory-Guide 1.4,Rev.2,"Assumptions UsedforEvaluating thePotential Radiological Consequences ofaLOCAforPressurized MaterReactors",

June1974.8.NRCRegulatory Guide1.109,Rev.1,"Calculation ofAnnualDosestoManFromRoutineReleasesofReactorEffluents forthePurposeofEvaluating Compliance with10CFRPart50AppendixI",Oct.1977.9.Lutz,R.J.,"IodineandCesionSpikingSourceTermsforAccidentAnalysis,"

MCAP-9964, Rev.1,July1981.57

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