ML17309A545
ML17309A545 | |
Person / Time | |
---|---|
Site: | Ginna |
Issue date: | 05/23/1994 |
From: | MECREDY R C ROCHESTER GAS & ELECTRIC CORP. |
To: | JOHNSON A R NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation |
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ML17263A656 | List: |
References | |
RTR-NUREG-1431 NUDOCS 9405310164 | |
Download: ML17309A545 (71) | |
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..ACCELERATED DISTRIBUTION DEMONS+ATION SYSTEMJIREGULATORY INFORMATION DISTRIBUTION SYSTEM(RIDS)ACCESSION NBR:9405310164 DOC.DATE:
94/05/23NOTARIZED:
YESDOCKETFACIL:50-244 RobertEmmetGinnaNuclearPlant,Unit1,Rochester G05000244AUTH.*NAME AUTHORAFFILIATION MECREDY,R.C.
Rochester Gas6ElectricCorp.RECIP.NAME RECIPIENT AFFILIATION JOHNSON,A.R.
ProjectDirectorate I-3+5R
SUBJECT:
Forwardsapplication foramendtolicenseDPR-18,increasing allowable RCAtoimprovedTSvalues(NUREG-1431).
IWestinghouse proprietary reptWCAP-11668 6nonproprietary reptWCAP-11678 encl.Proprietary reptWCAP-11668 withheld.
DDISTRIBUTION CODE:AP01DCOPIESRECEIVED:LTR JENCLLSIZE:/STITLE:Proprietary ReviewDistribution
-PreOperating License6Operating R/NOTES:License Expdateinaccordance with10CFR2,2.109(9/19/72).
05000244ARECIPIENT IDCODE/NAME PD1-3LAJOHNSON,A COPIESLTTRENCL1133RECIPIENT IDCODE/NAME PD1-3PDCOPIESLTTRENCL11DDINTERNAL:
AEO~DOA~GFfQEEXTERNALNRCPDR01111110OGC/HDS110DSNOTETOALL"RIDS"RECIPIENTS:
DDPLEASEHELPUSTOREDUCEWASTE!CONTACTTHEDOCUMENTCONTROLDESK,ROOMP1-37(EXT.20079)TOELIMINATE YOURNAMEFROMDISTRIBUTION LISTSFORDOCUMENTS YOUDON'TNEED!TOTALNUMBEROFCOPIESREQUIRED:
LTTR9ENCL7 Itg~0<~
/////I///////
'g//Z1//I///I/I///////////
i////I//////SKfROCHESTER GASANDELECTRICCORPORATION o89EASTAVENUE,ROCHESTER N.Y.14649-0001 ROBERTC.MECREDYVicePresident ClnnaNuclearProduction May23,1994TELEPHONE hREACODE7tB5462700U.S.NuclearRegulatory Commission DocumentControlDeskAttn:AllenR.JohnsonProjectDirectorate I-3Washington, D.C.20555
Subject:
Application forAmendment toOperating LicenseReactorCoolantActivityTechnical Specifications Rochester GasandElectricCorporation R.E.GinnaNuclearPowerPlantDocketNo.50-244Ref.(a):NRCLetter,C.RossitoA.Ladieu(WOG),"Acceptance forReferencing ofLicensing TopicalReportWCAP-10698...",
March30,1987.(b):NUREG-0916, "SafetyEvaluation ReportRelatedtotheRestartofR.E.GinnaNuclearPowerPlant",May1982.(c):RG&ELetter,R.MecredytoA.Johnson(NRC),"Emergency ResponseCapability...",
October14,1992.(d):NRCLetter,A.JohnsontoR.Mecredy(RG&E),Emergency ResponseCapability
-Conformance toRegulatory Guide1.97,revision3",February24,1993.(e):WOGLetter,L.WalshandA.EngeltoR.Jones(NRC),"Westinghouse OwnersGroupSteamGenerator TubeUncoveryIssue",March31,1992.(f):NRCLetter,R.JonestoL.Walsh(WOG),"Westinghouse OwnersGroup,SteamGenerator TubeUncoveryIssue",March10,1993.
DearMr.Johnson:
WCAP-11668 (Proprietary)/WCAP-11678 (Non-Proprietary) evaluatethepotential radiological consequences duetoasteamgenerator tuberupture(SGTR)fortheR.E.GinnaNuclearPowerPlant.Thisg'Ti4053101b4'Tl40523 PDR"ADOt"K'05000244 Thepurposeofthisapplication forAmendment toOperating LicenseistoamendAppendixAofthatLicensetoincreasetheTechnical Specification allowable primarycoolantiodine(I-131)activitylimitfrom0.2pC+igmto1.0pCi/gm; andthetotalprimarycoolantactivityfrom84/EpCi/gmtotheStandardTechnical Specification valueof100/EpCi/gm,consistent withtheImprovedTechnical Specifications (NUREG-1431).
evaluation utilizestheanalysismethodology ofWCAP-10698-P-A "SGTRAnalysisMethodology toDetermine theMargintoSteamGenerator Overfill."
RG&Ehasmettherequirements forusageofWCAP-10698 asoutlinedinNuclearRegulatory Commission letterfromC.E.Rossi(NRC)toA.E.Ladieu(WOG),(Reference a).Theletterrequiredeachutilitytoprovidefiveplantspecificinputs:1.Demonstration thatcriticaloperatoractiontimesusedintheanalysisarerealistic andconsistent withthoseobservedduringsimulator exercises.
2.AsitespecificSteamGenerator TubeRuptureradiological offsiteconsequence analysis.
3.Astructural, analysisofthemainsteam'inesdemonstrating adequacyunderwater-filled conditions.
4.Alistofsystems,components, andinstrumentation creditedforaccidentmitigation andthespecified safetygradeforeach.5.Acomparison oftheplanttothe"bounding plant"usedinWCAP-10698.
Items2and5areaddressed in.thesitespecificanalysisbeingsubmitted withthisletter,WCAP-11668 (Proprietary).
Item3wasaddressed duringthereviewoftheSteamGenerator TubeRuptureincidentatGinnaStation.Itsacceptability isdocumented inNUREG-0916, (Reference b).Item4iscontained inourpost-accidentinstrumentation submittal (Reference c)(re.Regulatory Guide1.97).NRCreviewandacceptance ofthisinformation isdocumented inreference d.Item1isdiscussed below.DuringtheweekofAugust19through23,1991simulator runsofthetwomostlimitingcasesidentified inWCAP-11668 (Proprietary)/
WCAP-11678 (Non-Proprietary),
weremadetovalidateassumedoperatorresponsetimes.Thesesimulator runsdemonstrated thatnotonlyweretheoperatorresponsetimesassumedintheWCAPsconservative withadequatemargin,butalsothatrecentrefinements intheemergency operating procedures havefurtherreducedthelikelihood ofoverfilling therupturedsteamgenerator.
Forthetwolimitingcasesidentified operatorresponseprevented overfillwithsignificant margin,andterminated breakflowinunder45minutes.Inbothcasesitwasnecessary tousetheWCAPassumedtimesforoperatoractionoutsidethecontrolroom.Thesetimeswerethelimitingfactorsinthescenarios, ascontrolroomoperators hadtowaittoproceedwithfurthermitigating actionsuntiltheseactionswereassumedtobecompleted.
Operatorcritiquefollowing thesessionsindicated thattheyfeltthesetimeswereunrealistically conservative.
We,therefore, feelthatactualmitigation timeswouldbeevenlessthanthosedemonstrated duringthesimulator exercise.
WCAP-11668/11678 assumesthetuberuptureremainscoveredthrough-ItI outtheevent.Morerecentlyithasbeensuggested that,thisassumption maynotbeconservative.
TheWestinghouse OwnersGroup(WOG)hasundertaken aprogramtoassesstheconsequences oftuberuptureuncovery.
Theresultsindicatethattheincreaseindosesisinsignificant.
Theseresultsweretransmitted tothestaff(Reference e).Thestaffhasreviewedandapprovedthistransmittal (reference f).Therefore, wefeelthisissuehasbeenadequately addressed.
ItshouldbenotedthataproposaltomodifySection3.1.4.3.a hasalreadybeensubmitted totheNRCvialetterMay13,1994.Page3.1-21ofAttachments BandCisbeingsubmitted inbothversions, sothatapprovalisnotdependent onthesequenceofproposedLicenseAmendment Requestreviews.WerequestthatuponNRCapproval, thisamendment shouldbeconsidered effective immediately andimplemented within60days.Veryrulyyours,oertc.ecryBJF/190Attachment
Enclosures:
1~One(1)submittal ofanApplication forAmendment toOperating Licenseandassociated safetyevaluation.
2~3~4~One(1)copyofanApplication forWithholding, CAW-87-123, datedDecember3,1987,accompanying Affidavit, andProprietary Information NoticeOne(1)copyofWCAP-11668, "LOFTTR2AnalysisofPotential Radiological Consequences Following aSteamGenerator TubeRuptureattheR.E.GinnaNuclearPlant",November1987(Proprietary).
One(1)copyofWCAP-11678, "LOFTTR2AnalysisofPotential Radiological Consequences Following aSteamGenerator TubeRuptureat,theR.E.GinnaNuclearPlant",November1987(Non-Proprietary).
xc>>Mr.AllenR.Johnson(MailStop14Dl)ProjectDirectorate I-3Washington, D.C.20555U.S.NuclearRegulatory Commission RegionI475Allendale RoadKingofPrussia,PA19406GinnaSeniorResidentInspector WESTINGHOUSE PROPRIETARY CLASS2WCAP"1166874>5'9QVLOFTTR2ANALYSISOFPOTENTIAL RADIOLOGICAL CONSEQUENCES FOLLOWING ASTEAMGENERATOR TUBERUPTUREATTHER.E.GINNANUCLEARPOWERPLANT0.J.MendlerK.RubinNOVEMBER1987NuclearSafetyDepartment Thisdocumentcontainsinformation proprietary toWestinghouse ElectricCorporation; itissubmitted in.confidence andistobeusedsolelyforthepurposeforwhichitisfurnished andreturneduponrequest.Thisdocumentandsuchinformation isnottobereproduced, transmitted, disclosed orusedotherwise inwholeorinpartwithoutauthorization ofWestinghouse ElectricCorporation, NuclearEnergySystems.Westinghouse ElectricCorporation NuclearEnergySystemsP.O.Box355Pittsburgh, Pennsylvania 152301987byWestinghouse ElectricCorporation 1074v:1OP/120487 IP.'\10 WESTINGHOUSE PROPRIETARY CLASS2Thisdocumentcontainsmaterialthatisproprietary totheWestinghouse ElectricCorporation.
Thispropr'ietary information hasbeenmarkedbymeansofbrackets.
Thebasisformarkingthematerialproprietary isidentified bymarginalnotesreferring tothestandards inSection8oftheaffidavit ofR.A.Wiesemann ofrecord"IntheHatterofAcceptance CriteriaforEmergency
.CoreCoolingSystemsforLightWaterCooledNuclearPowerReactors(DocketNo.RH-50-1)"
atteanscript pages3706through3710(February 24,1972).'Duetotheproprietary natureofthematerialcontained inthisreportwhichwasobtainedatconsiderable Westinghouse expenseandthereleaseofwhichwouldseriously affectourcompetitive
- position, werequestthisinformation tobewithheldfrompublicdisclosure inaccordance withtheRulesofPractice, 10CFR2.790,andthattheinformation presented thereinbesafeguarded inaccordance with10CFR2.903.Webelievethatwithholding thisinformation willnotadversely affectthepublicinterest.
Thisinformation isforyourinternaluseonlyandshouldnotbereleasedtopersonsororganizations outsidethedirectorate ofRegulation andtheACRSwithoutpriorapprovalofWestinghouse ElectricCorporation.
Shoulditbecome1necessary toreleasethisinformation tosuchpersonsaspartofthereviewprocedure, pleasecontactWestinghouse ElectricCorporation andtheywillmakethenecessary arrangements requiredtoprotecttheirproprietary'nterests.
1D74v:1D/7120B7 WESTINGHOUSE PROPRIETARY CLASS2TABLEOFCONTENTSPacaesI.INTRODUCTION II.THERHALHYDRAULIC ANALYSISA.B.C.D.E.F.DesignBasisAccidentConservative Assumptions OperatorActionTimesTransient Description
-Case1Transient Description
-Case2HassReleases236132434III.RADIOLOGICAL CONSEQUENCES ANALYSISIV.CONCLUSION 4358V.REFERENCES 591074v:1D/112087 00-WESTINGHOUSE PROPRIETARY CLASS2I.INTRODUCTION Anevaluation ofthepotential radiological consequences duetoasteamgenerator tuberupture(SGTR)eventhasbeenperformed fortheR.E.Ginnanuclearpowerplanttodemonstrate thattheoffsiteradiation doseswillbelessthantheallowable guidelines basedontheStandardTechnical Specification limitonprimarycoolantactivity.
Theevaluation discussed hereinassumesthat151.ofthesteamgenerator tubesareplugged.Adesignbasissteamgenerator tuberupturewasanalyzedforGinnausingthemethodology developed inMCAP-10698 (reference 1)andthesupplement toHCAP-10698 (reference 2).Twosinglefailurecaseswereconsidered todetermine whichisthemostlimitingsinglefailureforGinnawithrespecttoradiological.
consequences.
Thetwocasesexaminedwere:a,cCase1Intactsteamgenerator poweroperatedreliefvalve(PORV)failsclosedandmustbelocallyopened.Case2Rupturedsteamgenerator poweroperatedreliefvalvefailsopenandmustbelocallyisolated.
PlantresponsetotheeventwasmodeledusingtheLOFTTR2computercodewithconservative assumptions ofbreaksizeandlocation, condenser availability andinitialsecondary watermassinthefaultedsteamgenerator.
Theanalysismethodology includesthesimulation oftheoperatoractionsforrecoveryfrom'steamgenerator tuberupturebasedontheWestinghouse OwnersGroupEmergency ResponseGuidelines, whicharethebasisfortheGinnaEmergency Operating Procedures.
Themassreleaseswerecalculated withtheLOFTTR2~programfromtheinitiation oftheeventuntiltermination ofthebreakflow.Forthetimeperiodfollowing breakflowtermination, steamreleasesandfeedwater flowsfromtheintactandfaultedsteamgenerators weredetermined fromamassandenergybalanceusingthecalculated RCSandsteamgenerator conditions atthetimeofleakagetermination.
Themassreleasesforbothcaseswereusedtodetermine theradiation dosesattheexclusion areaboundaryandlowpopulation zoneassumingthattheprimarycoolantactivity'isattheStandardTechnical Specification limitpriortotheaccident.
1074v:1D/112087 MESTINGHOUSE PROPRIETARY CLASS2II.THERMALHYDRAULIC ANALYSISIntegrated massreleasestotheatmosphere andcondenser duringasteamgenerator tuberuptureeventwerecalculated forvarioustimeperiodsduringtheaccident.
Thissectionincludesthemethodsandassumptions usedtomodeltheSGTReventandcalculate themassreleases, aswellasthesequenceofeventsfortherecovery.
A.DesinBasisAccidentTheaccidentmodeledisthecompleteseverance ofasteamgenerator tubelocatedatthetubesheetonthecoldlegside.Itwasalsoassumedthatlossofoffsitepoweroccurredatthetimeofreactortrip,andtheworstrodwasassumedtobestuckatreactortrip.a,cThemostlimitingsinglefailurewithrespecttosteamgenerator overfillwasdetermined byreference 1tobeafailedclosedPORVontheintactsteamgenerator.
SinceGinnaisatwoloopplant,theintactsteamgenerator PORVmustbelocallyopenedbeforeRCScooldowncanbegin.Thisadditional timetolocallyopentheintactsteamgenerator PORVwilldelayRCSdepressurization, causinganincreaseintotalprimarytosecondary leakage.Consequently, morewaterwillaccumulate inthefaultedsteamgenerator.
Thecasewheretheintactsteamgenerator PORVfailstoopenondemandandmustbelocallyopenedwillbereferredtoasCase1.Themostlimitingsinglefailurewithrespecttooffsitedoseswasdetermined byreference 2tobeafailedopenPORVonthefaulte'dsteamgenerator.
FailureofthisPORVwillcauseanuncontrolled depressurization ofthefaultedsteamgenerator whichwillincreaseprimarytosecondary leakage.Pressureintherupturedsteamgenerator willremainbelowthatintheprimarysystemuntilthefailedPORVcanbeisolated, andrecoveryactionscompleted.
Thecasewherethefaulted'team generator PORVfailsopenandmustbelocallyisolatedwillbereferredtoasCase2.1074v:1D/112087 WESTINGHOUSE PROPRIETARY CLASS2B.Conservative AssumtionsPlantresponses andmassreleasesfromtheintactandfaultedsteamgenerator priortobreakflowtermination werecalculated usingLOFTTR2.WhilemodelingtheSGTReventthefollowing assumptions weremade:1.ReactorTrionOvertemeratureDelta-Ta,cAturbinerunbackcanbeinitiated automatically ortheoperatorcanmanuallyreducetheturbineloadtoattempttopreventareactortriponovertemperature delta-T.Althoughturbinerunbackissimulated inthisanalysis, creditis.nottakenfordelayingreactortrip.Reactortripisassumedtooccuronovertemperature delta-T.Duetotheassumedlossofoffsitepowerthecondenser isnotavailable forsteamreleasesoncethereactoristripped.Consequently, afterreactortripthesteamgenerator PORYsareusedforsteamreleases.
Thusanearliertriptimeleadstomoresteamreleasedtotheatmosphere fromthefaultedandintactsteamgenerators.
2.PoweraTheinitialsteamgenerator watermassdecreases withincreasing powerlevel.,Thus,alowerinitialpowerresultsinahigherinitialsteamgenerator secondary watermasswhichisconservative.
Onthisbasis,100%nominalpowerwasassumedfortheanalysisratherthanconsidering anoverpower factor.3.Pressurizer WaterLevelTheRCSdepressurization rateincreases afterthepressurizer empties.Ahigherpressurizer waterlevelwillincreasethetimerequiredforthepressurizer toempty.Thisresultsinmaintaining ahigherprimarytosecondary pressuredifferential andthusalargerbreakflowrateforalongertimeperiod.Therefore, itisconcluded thatmaximizing thepressurizer waterlevelisconservative.
a,c1074v:1D/112087 HESTINGHOUSE PROPRIETARY CLASS24.SteamGenerator Seoond~ar MassAhigherinitialsecondary watermassintherupturedsteamgenerator wasdetermined byReference 1tobeconservative foroverfill.
FortheCase1analysisturbinerunbackwasassumedinitiated andwassimulated byartificially increasing initialsteamgenerator watermass.Theinitialsteamgenerator totalfluidmasswasassumedtobelOAabovenominalvalueplusthedifferential massbetween100%powerand70Ãpowertosimulateturbinerunback.However,ifsteamgenerator overfilldoesnotoccur,alowerinitialmassintheruptur'ed steamgenerator resultsinaconservative prediction ofoffsitedoses..Thus,forCase2theinitialsecondary masswasassumedtocorrespond tooperation at10Kbelownominalsteamgenerator watermass.a,c5.BreakLocationThetuberuptureanalyzedisadouble-ended breakofonesteamgenerator tubelocatedatthetopofthetubesheetontheoutletsideofthesteamgenerator.
Thelocationofthebreakonthecoldsideofthesteamgenerator resultsinhigherprimarytosecondary leakagethanabreakonthehotsideofthesteamgenerator asdetermined byreference 1.Therefore, itisconcluded thatthecoldlegsidebreaklocationisconservative.
4i,C6.ReactorTriOelaAsnotedpreviously, theresultsforcaseswhichproduceanearlierreactortriparemoreconservative withrespecttotheradiological consequences fromaSGTR.Thus,aminimumdelaytimefromthereactortripsignaltoreactortripisconservative fortheanalysis.
Inaddition, asnotedabove,nocreditistakenforturbinerunbackdelayingreactortrip.a,c.1074v:10/112387 ttESTINGHOUSE PROPRIETARY CLASS27.T~tiTiD1Following areactortrip,theturbinewillbeautomatically trippedafterasuitabledelaytime.Minimizing thedelaytimebetweenreactortripandturbinetripreducestheamountofsteamflowtotheturbineandincreases the.secondary waterinventory.
Thus,aminimumdelaytimebetweenreactortripandturbinetripisconservative fortheSGTRanalysis.
a,c8.SteamGenerator ReliefValvePressureSetointHithalossofoffsitepower,thesecondary pressurewillincreasefollowing reactorandturbinetrip,andsteamwillberelievedthroughthesteamgenerator PORVsandsafetyvalves.Alowersteamgenerator reliefvalvepressuresetpointleadstoahigherprimarytosecondary pressuredifferential andthushigherprimarytosecondary leakage.Thus,theuseofthelowestsetpointforthesteamgenerator.
reliefvalvesisconservative fortheanalysis.
SincethePORVsetpointislowerthan.thesafetyvalvesetpoints, theuseofthePORVsetpointof1050psigforsteamreliefismoreconservative, 9.Pressurizer PressureforSIInitiation Theuseofthemaximumpressurizer pressuresetpointforSIinitiation resultsinearlieractuation oftheSIsystem.Thisleadstothemaintenance ofahigherprimarytosecondary pressuredifferential andconsequently ahigherbreakflowrateforalongertimeperiod.Thus,theuseofthemaximumpressurizer pressuresetpointforSIinitiation
.intheanalysisisconservative.
a,c10.LeakaeafterOverfilla,cOverfillisassumedtooccuriftherupturedsteamgenerator becomeswatersolid.Nocreditistakenforsteamlinevolume.1074v:10/1 12087 WESTINGHOUSE PROPRIETARY CLASS211.FlashinFractiona,cWhencalculating theamountofbreakflowthatflashestosteam,100percentofthebreakflowisassumedtocomefromthehotlegsideofthebreak.Sincethetuberuptureflowactuallyconsistsofflowfromthehotlegandcoldlegsidesofthesteamgenerator, thetemperature ofthecombinedflowwillbelessthanthehotlegtemperature andtheflashingfractionwillbecorrespondingly lower.Thustheassumption that100percentofthebreakflowcomesfromthehotlegisconservative foraSGTRanalysis.
C.eratorActionTimesIntheeventofanSGTR,theoperatorisrequiredtotakeactionstostabilize theplantandterminate theprimarytosecondary leakage.Anevaluation hasbeenperformed (reference 1)toestablish theoperatoractiontimesfor'useintheanalysisofadesignbasisSGTRevent.TheoperatoractionswhicharerequiredforrecoveryfromanSGTRandtheavailable dataonthetimestoperformtheseactionshaveb'eenreviewed.
Theavailable dataonoperatoractiontimesforanSGTRincludesinformation whichhasbeenobtainedfromreactorplantsimulator studiesaswellasplantdatafromfiveactualSGTRevents.Usingthisdata,operator-actiontimeshavebeenestablished.
whichareconsidered tobeappropriate foradesignbasisSGTRevent.TheseoperatoractiontimeswerebeusedasinputfortheanalysisofthedesignbasisSGTRevent.ThemajoroperatoractionsforSGTRrecoverywhichareincludedintheE-3guideline oftheWestinghouse OwnersGroupEmergency ResponseGuidelines wereexplicitly modeledintheanalysis.
Theoperatoractionsmodeledincludeidentification andisolation oftherupturedsteamgenerator, cooldownanddepressurization oftheRCStorestoreinventory, andtermination ofSItostopprimarytosecondary leakage.Theseoperatoractionsaredescribed below.1074v:1D/112087 MESTINGHOUSE PROPRIETARY CLASS21.I.dentify therupturedsteamgenerator (step2).Highsecondary sideactivity, asindicated bythesteamgenerator blowdownlineradiation monitororairejectorradiation monitor,typically willprovidethefirstindication ofanSBTRevent.Therupturedsteamgenerator canbeidentified byhighactivityinthecorresponding steamgenerator blowdownline,mainsteamline, orwatersample.ForanSBTRthatresultsinahighpowerreactortrip,thesteamgenerator waterlevelwilldecreaseoff-scale onthenarrowrangeforbothsteamgenerators.
Theauxiliary feedwater (AFM)flowwillbegintorefillthesteamgenerators, typically distributing approximately equalflowtobothsteamgenerators.
Sinceprimarytosecondary leakageaddsadditional inventory whichaccumulates intherupturedsteamgenerator, levelwillreturntothenarrowrangeinthatsteamgenerator significantly earlierandwillcontinuetoincreasemorerapidly.Thisresponseprovidesconfirmation of.anSGTReventandalsoidentifies therupturedsteamgenerator.
2.Isolatetherupturedsteamgenerator fromtheintactsteamgenerator andisolatefeedwater totherupturedsteamgenerator.(steps 3and4).Onceatuberupturehasbeenidentified, recoveryactionsbeginbyisolating steamflowfromandstoppingfeedwater flowtotherupturedsteamgenerator.
Inadditiontominimizing radiological
- releases, thisalsoreducesthepossibility offillingtherupturedsteamgenerator withwaterby1)minimizing theaccumulation offeedwater flowand2)enablingtheoperatortoestablish apressuredifferential betweentherupturedandintactsteamgenerators asanecessary steptowardterminating primarytosecondary leakage.Intheguideline forsteamgenerator tuberupturerecoveryintheERGs,theoperatorisdirectedtomaintainthelevelintherupturedsteamgenerator betweenjustonspanand50%onthenarrowrangeinstrument.
Reference 1assumedthattherupturedsteamgenerator wouldbeisolatedwhenlevelinthesteamgenerator reached[midwaybetweenthesepoints]'074v:1D/112487 WESTINGHOUSE PROPRIETARY CLASS2[(33%narrowrangelevel).]'orGinnaitwasalsoconservative touse[33percent]'flevelforisolation.
Therupturedsteamgenerator wasassumedtobeisolatedat[33percentnarrowrangelevelorat10minutes,whichever waslonger.]'.CooldowntheReactorCoolantSystem(RCS)usingtheintactsteamgenerator (step14).Afterisolation oftherupturedsteamgenerator, theRCSiscooledasrapidlyaspossibletolessthansaturation temperature corresponding totherupturedsteamgenerator pressurebydumpingsteamfromonlytheintactsteamgenerator
.Thisensuresadequatesubcooling inthe.RCSafterdepressurization totherupturedsteamgenerator pressureinsubsequent actions.,
Withoffsitepoweravailable, thenormalsteamdumpsystemtothecondenser willprovidesufficient capacitytoperformthiscooldownrapidly'.
Ifoffsitepowerislost,theRCSiscooledusingthepower-operated reliefvalve(PORV)ontheintactsteamgenerator sinceneitherthesteamdumpvalvesnorthecondenser wouldbeavailable.
ItisnotedthatRCSpressurewilldecreaseduringthecooldownasshrinkage ofthereactorcoolantexpandsthesteambubbleinthepressurizer.
4.Depressurize theRCStorestorereactorcoolantinventory (steps17or18).Whenthecooldowniscompleted, SIflowwillincreaseRCSpressureuntilbreakflowmatchesSIflow.Consequently, SI'flowmustbeterminated tostopprimarytosecondary leakage.However,adequatereactorcoolantinventory mustfirstbeassured.Thisincludesbothsufficient reactorcoolantsubcooling andpressurizer inventory tomaintainareliablepressurizer levelindication afterSIflowisstopped.SinceleakagefromtheprimarysidewillcontinueafterSIflowisstoppeduntilRCSandrupturedsteamgenerator pressures
- equalize, an"excess"amountofinventory isneededtoensure1074v:10/112487 WESTINGHOUSE PROPRIETARY CLASS2pressurizer levelremainsonspan.The"excess"amountrequireddependsonRCSpressureandreducestozerowhenRCSpressureequalsthepressureintherupturedsteamgenerator.
Toreducebreakflowandestablish sufficient pressurizer level,RCSpressureisdecreased byopeningthepressurizer PORV.5.Terminate SItostopprimarytosecondary leakage(steps21-23).Thepreviousactionswillhaveestablished adequateRCSsubcooling, secondary sideheatsink;andreactorcoolantinventory following anSGTRtoensurethatSIflowisnolongerneeded.Whentheseactionshavebeencompleted, SIflowmustbestoppedtoprevent'epressurization oftheRCSandtoterminate primarytosecondary leakage.Primarytosecondary leakagewillcontinueafterSIflowisstoppeduntilRCSpressureandrupturedsteamgenerator pressures equalize.
Chargingflow,letdown,andpressurizer heaterswillthenbecontrolled topreventrepressurization oftheRCS'ndreinitiation ofleakageintotherupturedsteam.generator.
SincethesemajorrecoveryactionswillbemodelledintheSGTRanalysis, itisnecessary toestablish thetimesrequiredtoperformtheseactions.Althoughtheintermediate stepsbetweenthemajoractionswillnotbeexplicitly
- modelled, itisalsonecessary toaccountforthetimerequiredtoperformthesteps,Itisnotedthatthetotaltimerequiredtocompletetherecovery-operations consistsofbothoperatoractiontimeandsystem,orplant,responsetime;Forinstance, thetimeforeachofthemajorrecoveryoperations (i.e.,RCScooldown, RCSdepressurization,'tc.)
isprimarily duetothetimerequiredforthesystemresponse, whereastheoperatoractiontimeisreflected bythetimerequiredfortheoperatortoperformtheintermediate actionsteps.'TheoperatoractiontimestoinitiateRCScooldown, RCSdepressurization andsafetyinjection termination weredeveloped inreference 1andarelistedinTableII.1.Inadditiontotheoperatoractiontimesdeveloped inreference 1,Rochester GasandElectricsuppliedtheoperatoraction1074v:1D/112087 MESTINGHOUSE PROPRIETARY CLASS2timesassociated withrecovering fromthesinglefailures(Reference 3).[Theseoperator'actions, whichwouldoccuroutsidethecontrolroom,includelocallyopeningtheintactsteamgenerator PORV,locallyclosingtheintactsteamgenerator PORVblockvalveandlocallyclosingthefaultedsteamgenerator PORVblockvalve.]'hetimesassociated withperforming theseoperatoractionsarelistedinTableII.2.[Itisnotedthatthe20minutestoopentheintactsteamgenerator PORVconsistsof10minutestoidentifyandlocatethevalveand10minutestolinearlyopenthePORV.Duetolimitations ofLOFTTR2,theoperatoractiontoopentheintactsteamgenerator PORVwassimulated asastepopeningaftera15minutedelay,whichresultsinanequivalent integrated steamflowthroughthePORVattheendofthe20minuteperiod.]'074v:io/11208710 MESTINGHOUSE PROPRIETARY CLASS2TABLEII.1OPERATORACTIONTIMESFORDESIGNBASISSGTRANALYSISActionTimeminIdentifyandisolaterupturedSGHaximumof10minorcalculated timetoreach334narrowrangelevelintherupturedSGOperatoractiontimetoinitiatecooldownCooldownCalculated timeforRCScooldownOperatoractiontimetoinitiatedepressurization Depressurization Calculated timeforRCSdepressurization OperatoractiontimetoinitiateSItermination SItermination andpressureequalization Calculated timeforSItermination andequalization ofRCSandrupturedSGpressures 1074v:1D/112087 WESTINGHOUSE PROPRIETARY CLASS2TABLEII.2ActionGINNASPECIFICOPERATORACTIONTIMESTimeminQ,CFaultedSteamGenerator PORVBlockValveClosing-Local Action15IntactSteamGenerator PORVOpening-Local Action20IntactSteamGenerator PORVBlockValveClosing-Local Action1074v:1D/112087 12 II'ESTINGHOUSE PROPRIETARY CLASS2D.Transient Descrition-Case1[Case1addresses aSGTRinwhichthesinglefailureassumedisthattheintactsteamgenerator PORVfailstoopenondemandandmustbelocallyopened.]'hesequence, ofeventsforCase1ispresented inTableII.3.Following thetuberupture,reactorcoolantflowsfromtheprimaryintothesecondary sideoftherupturedsteamgenerator sincetheprimarypressureisgreaterthanthesteamgenerator pressure.
Inresponsetothislossofreactorcoolant,pressurizer leveldecreases asshowninFigureII.1.TheRCSpressurealsodecreases asshowninFigureII.2asthesteambubbleinthepressurizer expands.AstheRCSpressuredecreases duetothecontinued primarytosecondary leakage,automatic reactortripoccursonanovertemperature delta-Ttripsignal.Afterreactortrip,corepowerrapidlydecreases todecayheatlevels.Theturbinestopvalvescloseandsteamflowtotheturbineisterminated.
Thesteamdumpsystemisdesignedtoactuatefollowing reactortriptolimittheincreaseinsecondary
- pressure, butthesteamdumpvalvesremainclosedduetothelossofcondenser vacuumresulting fromtheassumedlossofoffsitepoweratthetimeofreactortrip.Thus,theenergytransferfromtheprimarysystemcausesthesecondary sidepressuretoincreaserapidlyafter'reactortripuntilthesteamgenerator.
PORVslifttodissipate theenergy,asshowninFigureII.3.TheRCSpressuredecreases morerapidlyafterreactortripasenergytransfertothesecondary shrinksthereactorcoolantandtheleakflowcontinues todepleteprimaryinventory.
ThedecreaseinRCSinventory resultsinalowpressurizer pressureSIsignal.Pressurizer levelalsodecreases morerapidlyfollowing reactortripandthepressurizer eventually emptiesasshowninFigureII.1.Afterthepressurizer empties,theRCSpressurerapidlydecreases asshowninFigureII.2.1074v:10/120487 13 WESTINGHOUSE PROPRIETARY CLASS2Sinceoffsitepowerisassumedlostatreactor-trip, theRCPstripandagradualtransition tonaturalcirculation flowoccurs.Immediately following reactortripthetemperature riseacrossthecoredecreases ascorepowerdecays(seeFigure11.4),however,thetemperature risesubsequently increases asnaturalcirculation flowdevelops.
Thecoldlegtemperatures trendtowardthesteamgenerator temperature asthefluidresidence timeinthetuberegionincreases.
TheRCStemperatures continuetoslowlydecreaseduetothecontinued additionoftheauxiliary feedwater tothesteamgenerators untiloperatoractionsareinitiated tocooldowntheRCS.majorOperatorActions1.IdentifyandIsolatetheRupturedSteamGenerator Onceatuberupturehasbeenidentified, recoveryactionsbeginbyisolating steamflowfromtherupturedsteamgenerator and.throttling theauxiliary feedwater flowtotherupturedsteamgenerator.
Asindicated previously, therupturedsteamgenerator isassumedtobeidentified andisolatedwhenthenarrowrangelevelreaches[33%]'ntherupturedsteamgenerator orat[10]'inutesafter.initiation oftheSGTR,whichever islonger.ForGinna,thetimetoreach[33%]'slessthan[10]'inutes,thustherupturedsteamgenerator isassumedtobeisolatedat[10]'inutes.2.CooldowntheRCStoEstablish Subcooling MarginAfterisolation oftherupturedsteamgenerator, thereisa[5]'inuteoperator.
actiontimeimposedpriortoinitiating thecooldown.
Theactualdelaytimeusedintheanalysisis4secondslongerbecauseofthecomputerprogramrequirements forsimulating theoperatoractions.Afterthistime,actionsaretakentocooltheRCSasrapidlyaspossiblebydumpingsteamfromtheintactsteamgenerators.
Sinceoffsitepowerislost,theRCSiscooledbydumpingsteamtotheatmosphere usingthePORVontheintactsteamgenerator.
[ForCase1,aspreviously noted,theintactsteamgenerator]
'074v:1D/112487 14 MESTINGHOUSE PROPRIETARY CLASS2[PORVfailstoopen.Fortheanalysis, itwasassumedthatthevalvewasfullyopenedafteranadditional periodof15minutes(seepg.10).Thusat1804secondstheintactsteamgenerator PORVisopenedforRCScooldown.]
'hecooldowniscontinued unti1RCSsubcooling attherupturedsteamgenerator pressureis20'Fplusanallowance of17'Fforsubcooling uncertainty.
[Whentheseconditions aresatisfied itisassumedthatittakestheoperatorfiveminutestoclosetheintactsteamgenerator PORVblockvalve.]'tisnotedthatoverfilloftherupturedsteamgenerator occursduringthistimeperiodat'[2372]'econds,asshowninFigureII.6.Thiscooldownensuresthattherewillbeadequatesubcooling intheRCSafterthesubsequent depressurization oftheRCStotherupturedsteamgenerator pressure.
Thereduction intheintactsteamgenerator pressurerequiredtoaccomplish thecooldownisshowninFigureII.3,andtheeffectofthecooldownontheRCStemperature isshowninFigureII.4.TheRCSpressurealsodecreases duringthiscooldownprocessduetoshrinkage ofthereactorcoolantasshowninFigureII.2.3,Depressurize RCStoRestoreInventory AftertheRCScooldown, a[2]'inuteoperatoractiontimeisincludedpriortodepressurization.
TheRCSisdepressurized at2688secondstoassureadequatecoolantinventory priortoterminating SIflow.MiththeRCPsstopped,normalpressurizer'pray isnotavailable andthustheRCSisdepressurized byopeningapressurizer PORV.Thedepressurization iscontinued untilanyofthefollowing conditions aresatisfied:
RCSpressureislessthantherupturedsteamgenerator pressureandpressurizer levelisgreaterthan0%plusanallowance of3%forpressurizer leveluncertainty, orpressurizer, levelisgreaterthan80%minusanallowance of3%forpressurizer leveluncertainty, orRCSsubcooling islessthanthe17'Fallowance forsubcooling uncertainty.
TheRCSdepressurization reducesthebreakflowasshowninFigureII.5andincreases SIflowtorefillthepressurizer, asshowninFigureII.1.1074v:10/112487 15 WESTINGHOUSE PROPRIETARY CLASS24.Terminate SItoStopPrimarytoSecondary LeakageThepreviousactionsshouldhaveestablished adequateRCSsubcooling, verifiedasecondary sideheatsink,andrestoredthereactorcoolantinventory following aSGTRtoensurethatSIflowisnolongerneeded.Whentheseactionshavebeencompleted, theSIflowmustbestoppedtopreventrepressurization oftheRCSandtoterminate "primarytosecondary leakage.TheSIflowisterminated whentheRCSpressureincreases,,minimum AFWflowisavailable andatleastoneintactsteamgenerator levelisinthenarrowrange,RCSsubcooling isgreaterthanthe17'Fallowance forsubcooling uncertainty, andthepressurizer levelisgreaterthanthe3Xallowance forpressurizer leveluncertainty.
ToassurethattheRCSpressureisincreasing, SIwasnotterminated intheanalysisuntiltheRCSpressureincreased to50psiabovetherupturedsteamgenerator pressure.
Afterdepressurization iscompleted, anoperatoractiontimeof[1]'inuteisimposedpriortoSItermination.
Theprimarytosecondary leakagecontinues aftertheSIflowisterminated untiltheRCSandrupturedsteamgenerators equalize.
Thisoccurswhen'theintactsteamgenerator PORVislocallyopenedtocooldowntheRCSsothatsubcooling maybemaintained.
WhenthePORVisopenedtheincreased energytransferfromprimarytosecondary depressurizes theRCStotheruptured.steamgenerator pressure.
1074v:10/112087 16 MESTINGHOUSE PROPRIETARY CLASS2TABLEII.3SEQUENCEOFEVENTSEVENTCASE1Timesecd.,CReactorTrip50Ruptured.
SGIsolated600IntactSGPORVOpened1804OverfillRupturedSG2372IntactSGPORVIsolatedPRZRPORVOpenedPRZRPORVClosed256826882738SITerminated 2798IntactPORVOpened3288BreakFlowTerminated 34281074v:1D/112087 17 WESTINGHOUSE PROPRIETARY CLASS2GINNASTEAMGENERATOR TUBERUPTUREANALYSIS15PERCENTTUBEPLUGGINGCASE1188.88~78.68.4J68.t448.38.18~8.8..1Ei84.2E+84TINE(SEC).3Ei84.4E~84FigureII.1Pressurizer Level-Case11074v:1D/112087 18 MESTINGHOUSE PROPRIETARY CLASS2GINNASTEAMGENERATOR TUBERUPTUREANALYSIS15PERCENTTUBEPLUGGINGCASEI.25E+84.225Ei84.2E84.175E'84.15E+84Ld~,12SE~84LJOf~o.1E84Of758.588.258..IE~84.2E84.3E~84TIME(SEC).4E84FigureII.2RCSPressure-Case11074v:10/112087 19 MESTINGHOUSE PROPRIETARY CLASS2GINNASTEAMGENERATOR TUBERUPTUREANALYSISISPERCENTTUBEPLUGGINGCASEI.I4E84.12Ei84RUPTUREDLOOP.1E~84888.INTACTLOOPOCC)ill688.488.288.8..IE~84.2E84.3E~84.4E~84TINE(SEC)FigureII.3Secondary Pressure-Case11074v:1D/11208l 20 MESTINGHOUSE PROPRIETARY CLASS2GINNASTEAi1GENERATOR TUBERUPTUREANALYSISPERCENTTUBEPLUGGINGCASE1658.688.~558.4JCD588.~458.IX488.C)358.CDCD~388.258~288'..1E~84..2E~84TI11E(SEC).3E~84~4E~84FigureII.4IntactLoopHotandColdLegRCSTemperatures
-Case11074v:10/112087 21 MESTINGHOUSE PROPRIETARY CLASS2GINNASTEAI1GENERATOR TUBERUPTUREANALYSIS15PERCENTTUBEPLUGGINGCASE1168.I48.128'SSUEUlKlD88.C)68~hCEZIIJm48.28.-28...IE~84.2E~84TIt1EISEC).3E84.4E+84FigureII.5PrimarytoSecondary Leakage-Case11074v:1D/112087 22 MESTINGHOUSE PROPRIETARY CLASS2GINNASTEAI1GENERATOR TUBERUPTUREANALYSIS15PERCENTTUBEPLUGGINGCASE1.6E84.SE84~.4E~84~.3'40.2Ei84.1E84.lE.84.2E~B4.3E~84.4E~84TlNEtSEC)FigureII.SRupturedSGRaterVolume-Case11074v:1D/112081 23 WESTINGHOUSE PROPRIETARY CLASS2E.Transient Descrition-Case2[Case2addresses aSGTRinwhichthesinglefailureassumedisthatthefaultedsteamgenerator PORVfailsopenatthetimethefaultedsteamgenerator isisolated.]
'hus,theCase2transient issimilartotheCase1transient untilthattime..ThesequenceofeventsforCase2isIpresented inTableII.4.Following thetuberupturetheRCSpressuredecreases asshowninFigure11.7duetotheprimarytosecondary leakage.Inresponsetothisdepressurization, thereactortripsonovertemperature delta-T.Afterreactortrip,corepowerrapidlydecreases todecayheatlevelsandtheRCSdepressurization becomesmorerapid.Thesteamdumpsystemisinoperable duetotheassumedlossofoffsitepower,whichresultsinthesecondary pressurerisingtothesteamgenerator PORVsetpointasshowninFigure11.8.Thedecreasing pressurizer pressureleadstoanautomatic SIsignalonlowpressurizer pressure.
Pressurizer levelalsodecreases morerapidlyfollowing reactortripuntiliteventually empties,asshowninFigure11.9.majorOperatorActions1.IdentifyandIsolatetheRupturedSteamGenerator Therupturedsteamgenerator isassumedtobeidentified andisolatedat[10minutesaftertheinitiation oftheSGTRorwhenthenarrowrangelevelreaches33%,whichever timeisgreater.]
'orthiscase,thetimetoreach[33/]'arrowrangelevelis[652]'econds,andthus,itwasassumedthattherupturedsteamgenerator isisolatedatthattime.[Therupturedsteamgenerator PORVisalsoassumedtofailopenatthistime.]'hefailurecausesthesteamgenerator torapidlydepressurize, whichresultsinanincreaseinprimarytosecondary leakage.Thedepressu'rization oftherupturedsteamgenerator increases'he breakflowandenergytransferfromprimarytosecondary whichresultsinRCSpressureandtemperature decreasing morerapidlythaninCase1.Therupturedsteamgenerator 1074v:10/120487 24 MESTINGHOUSE PROPRIETARY CLASS2depressurization causesacooldownintheintactsteamgenerator loop.Asthe'ntact steamgenerator hotlegtemperature decreases belowthesteamgenerator watertemperature reverseheattransfertakesplaceasshowninFigureII.10.[Itisassumedthatthetimerequiredfortheoperatortoidentifythattherupturedsteamgenerator PORVisopenandtoclosetheassociated blockvalveis15minutes.Thus,at1558secondsthedepressurization ofrupturedsteamgenerator isterminated.]
',c2.CoolDowntheRCStoestablish Subcooling Margin[Aftertherupturedsteamgenerator PORVblockvalveisclosed,'here isa5minuteoperatoractiontimeimposedpriortoinitiation ofcooldown.]
'hedepressurization oftherupturedsteamgenerator affectstheRCScooldowntargettemperature sincethetemperature isdependent uponthepressureintherupturedsteamgenerator.
Since'ffsitepowerislosttheRCSiscooledbydumpingsteamtotheatmosphere usingtheintactsteamgenerator PORV.Thecooldowniscontinued untilRCSsubcooling attherupturedsteamgenerator pressureis20'Fplusanallowance of17'Fforinstrument uncertainty.
Hecauseofthelowerpressureintherupturedsteamgenerator theassociated temperature theRCSmustbecooledtoisalsolower,whichhastheneteffectofextending thetimeforcooldown.
ForCase2cooldownbeginsat[1858]'econds'andiscompleted at[2852]'econds.Thereduction intheintactsteamgenerator pressurerequiredtoaccomplish thecooldownisshowninFigureII.8,andtheeffectofthecooldownontheRCStemperature isshowninFigureII.10.TheRCSpressurealsodecreases duringthiscooldownprocessduetoshrinkage ofthereactorcoolantasshowninFigureII.7.3.Depressurize toRestoreInventory AftertheRCScooldown, a[2]'inuteoperatoractiontimeisincludedpriortodepressurization.
TheRCSisdepressurized at[2974]'econdstoassureadequatecoolantinventory priorto1074v:10/112487 25 HESTINGHOUSE PROPRIETARY CLASS2terminating SIflow,-HiththeRCPsstopped,normalpressurizer sprayisnotavailable andthustheRCSisdepressurized byopeningapressurizer PORV.Thedepressurization iscontinued untilanyofthefollowing conditions aresatisfied:
RCSpressureislessthantherupturedsteamgenerator pressureandpressurizer levelisgreaterthan0%plusanallowance of3%forpressurizer leveluncertainty, orpressurizer levelisgreaterthan80%minusanallowance of3%forpressurizer leveluncertainty, orRCSsubcooling islessthanthe17'Fallowance forsubcooling uncertainty.
TheRCSdepressurization reducesthebreakflowasshowninFigureII.11andincreases SIflowtorefillthepressurizer, asshowninFigure11.9.4.Terminate SItoStopPrimarytoSecondary Leakage,Thepreviousactionsshouldhaveestablished adequateRCSsubcooling, verifiedasecondary sideheatsink,andrestoredthereactorcoolantinventory following anSGTRtoensurethatSIflowisnolongerneeded.Nhentheseactionshavebeencompleted, theSIflowmustbestoppedtopreventrepressurization oftheRCSandtoterminate primarytosecondary leakage.TheSIflowisterminated whentheRCSpressureincreases,'minimum AFHflowisavailable andatleastoneintactsteamgenerator levelisinthenarrowrange,RCSsubcooling isgreaterthanthe17'Fallowance forsubcooling uncertainty, andthepressurizer levelisgreaterthanthe3%allowance forpressurizer leveluncertainty.
ToassurethattheRCSpressureisincreasing, SIwasnotterminated untiltheRCSpressureincreased to50psiabovetherupturedsteamgenerator pressure.
Afterdepressurization iscompleted, anoperatoractiontimeof[1]'inuteisimposedpriortoSItermination.
FigureII.11showsthattheprimarytosecondary leakagecontinues aftertheSIflowisstoppeduntiltheRCSandrupturedsteamgenerator pressureequalize.
TherupturedsteamwatervolumeisshowninFigureII.12.ForCase2,therupturedsteamgenerator doesnotoverfill.
1074v:1D/112487 MESTINGHOUSE PROPRIETARY CLASS2TABLEII.4SEQUENCEOFEVENTSCASE2EVENTTIMEsecReactorTrip49.4RupturedSGIsolatedRupturedSGPORVFailsOpena.cRupturedSGBlockValveClosed1558IntactSGPORVOpenedIntactSGPORVClosed18582852PRZRPORVOpenedPRZRPORVClosed29743006SITerminated 3066BreakFlowTerminated 34381D74v:1O/112087 27 WESTINGHOUSE PROPRIETARY CLASS2GINNASTEAt1GENERATOR TUBERUPTURE4NAL'/SIS 15PERCENTTUBEPLUGGING2588.2258.CASE2-2888.CCl758.1588.~1258.cnI888.758.588.258.8.8.588.1888.l588.2888'588.5888.5588."4888.TIME(SEC)
FigureII.7RCSPressure-Case21074v:10/112087 28 HESTINGHOUSE PROPRIETARY CLASS21488.GINNASTEAMGENERATOR TUBERUPTUREANALYSIS15PERCENTTUBEPLUGGINGCASE21288.-l888.w888.688.w488,RUPTUREDLOOPINTACTLOOP288,8.588.1888.:l588.
2888.2588.3888.3588.4888.TIME(SEC)
FigureII.8Secondary Pressure-Case21074v:10/112087 29 WESTINGHOUSE PROPRIETARY CLASS2G1NNASTEANGENERATOR TUBERUPTUREANALYS1515PERCENTTUBEPLUGGING188.CASE298.e8.78.LJw68.'58.48~38.028.18.8.8.588.1888.1588.2888'588.3888.3588.4888.TINE(SEC)FigureII.9Pressurizer Level-Case.21074v:10/1 1ZOST30 MESTINGHOUSE PROPRIETARY CLASS2GINNASTEAMGENERATOR TUBERUPTUREANALVSIS15PERCENTTUBEPLUGGING658.CASE2688.~558.O588.~z.458.o488.xIo358,388.TCOLDTHOTTHOT,TCOLDTHOTTCOLD258'88.8.588.1888.1588.2888.2588.3888.3588.4888.TIME(SEC)FigureII.10IntactLoopHotandColdLegRCSTemperatures
-Case21074v:1D/1 1208731 MESTINGHOUSE PROPRIETARY CLASS2GINNASTEAMGENERATOR TUBERUPTUREANALVSIS15PERCENTTUBEPLUGGINGCASE278.w68~58.o48.38.oc28.I8,-18.-288.588.1888.1588.2888.2588.3888.3588.4888.TIME(SEC)
FigureII.11PrimarytoSecondary Leakage-Case21074v:1D/112087 32 MESTINGHOUSE PROPRIETARY CLASS26888.GINNASTEAMGENERATOR TUBERUPTUREANALYSIS15PERCENTTUBEPLUGGING'ASE2H)I~5888.Ko4888.~5888.~g2888~I888.8.588.1888.1588.2888.2588.5888.5588.4888.,TIME(SEC)Figure11,12RupturedSGMaterVolume-Case21074v:1D/112087 33 WESTINGHOUSE PROPRIETARY CLASS2F.MassReleasesThemassreleasesweredetermined foreachofthesinglefailurecasesforuseinevaluating theexclusion areaboundaryandlowpopulation zoneradiation exposure.
Thesteamreleasesfromtherupturedandintactsteamgenerators, thefeedwater flowstotherupturedandintactsteamgenerators, andprimarytosecondary breakflowintotherupturedsteamgenerator weredetermined fortheperiodfromaccidentinitiation until2hoursaftertheaccidentandfrom2to8hoursaftertheaccident.
Thereleasesfor0-2.hoursareusedtocalculate theradiation dosesattheexclusion areaboundaryfora2hourexposure, andthereleasesfor0-8hoursareusedtocalculate theradiation dosesatthelowpopulation zoneforthedurationoftheaccident.
IntheLOFTTR2analyses, theSGTRrecoveryactionsintheE-3guideline weresimulated untilthetermination ofprimarytosecondary leakage.Aftertheprimarytosecondary leakageisterminated, theoperators willcontinuetheSGTRrecoveryactionsintheE-3guideline topreparetheplantforcooldowntocoldshutdownconditions.
Theseactionsincludeestablishing normalChemicalandVolumeControlSystem(CVCS)operation toprovidereactorcoolantinventory controlandaborationpath;restarting areac'torcoolantpump(RCP),ifnonearerunning,toensurehomogeneous RCSconditions andtoprovidenormalpressurizer spray;orstoppingoneRCP,ifbotharerunning,tominimizetheheatinput'uring thesubsequent cooldown; andtheactionsnecessary to'inimize thespreadofcontamination onthesecondary side.Whentheinstructions providedinE-3arecompleted, theplantshouldbecooledanddepressurized tocoldshutdownconditions.
Therearethreealternate meansofperforming thepost-SGTR cooldownprovidedintheWOGEmergency ResponseGuidelines.
Theguidelines are:ES-3.1,POST-SGTR COOLDOWNUSINGBACKFILL; ES-3.2,POST-SGTR COOLDOWNUSINGBLOWDOWN; andES-3.3,POST-SGTR COOLDOWNUSINGSTEAMDUMP.Thepreferred methodsareusingbackfillorblowdownsincethesemethodsminimizetheradioactivity releasedtotheatmosphere.
TheES-3.3guideline usingsteamdumpprovidesthefastestmethodfor1074v:1D/112087 34 WESTINGHOUSE PROPRIETARY CLASS2depressurizing theRCSandrupturedsteamgenerator.
Thismethodalsoresultsintheworstradiological
- releases, especially ifsteamdumptothecondenser isunavailable.
Therefore, themethodusingsteamdumpwasselectedforevaluation ofthelong-term massreleasessincethisproducesconservative resultsfortheoffsitedoseevaluation.
Itisnotedthattheuseofthesteamdumpmethodwouldnotbepermitted ifsteamgenerator overfilloccursandwaterentersthemainsteamlines.
ThehighlevelactionsfortheES-3.3guideline arediscussed below,1.PrepareforCooldowntoColdShutdownTheinitialstepstoprepareforcooldowntocoldshutdownareperformed intheE-3guideline following SItermination, andthesestepswillbecontinued inES-3.3iftheyhavenotalreadybeencompleted.
Afewadditional stepsarealsoperformed inES-3.3prior.toinitiating cooldown.
Theseincludeisolating thecoldleg.SIaccumulators topreventunnecessary injection, energizing pressurizer heatersasnecessary tosaturatethepressurizer waterandtoprovideforbetterpressurecontrol,andassuringadequateshutdownmarginintheeventofpotential borondilutionduetoin-leakage fromthe'ruptured steamgenerator.
2.CooldownRCStoResidualHeatRemoval(RHR)SystemTemperature TheRCSiscooledbysteamingandfeedingtheintactsteamgenerator similartoanormalcooldown.
Sinceallimmediate safetyconcernshavebeenresolved, thecooldownrateshouldbemaintained lessthanthemaximumallowable rateof100'F/hr.
Thepreferred meansforcoolingtheRCSissteamdumptothecondenser sincethisminimizes theradiological releasesandconserves feedwater supply.ThePORVfortheintactsteamgenerator canalsobeusedifsteamdumptothecondenser isunavailable.
WhentheRHRsystemoperating temperature isreached,thecooldownisstoppeduntilRCSpressurecanalsobedecreased.
Thisensuresthatpressure/temperature limitswillnotbeexceeded.
1074v:1D/112087 35 WESTINGHOUSE PROPRIETARY CLASS23.Depressurize RCStoRHRSystemPressureWhenthecooldowntoRHRsystemtemperature iscompleted, thepressureintherupturedsteamgenerator isdecreased byreleasing steamfromtherupturedsteamgenerator.
Steamreleasetothecondenser ispreferred sincethisminimizes radiological releases.
However,steamcanalsobereleasedtotheatmosphere usingthePORVontherupturedsteamgenerator.
Anevaluation ofthepotential radiological consequences shouldbeperformed beforereleasing steamfromtherupturedsteamgenerator totheatmosphere.
Astherupturedsteamgenerator pressureisreduced,theRCSpressureismaintained equaltothepressureintherupturedsteamgenerator inordertopreventin-leakage ofsecondary sidewateroradditional primarytosecondary leakage.Normalpressurizer sprayisthepreferred meansofRCSpressurecontrolsincethisconserves coolantinventory.
Ifpressurizer sprayisnotavailable, apressurizer PORVorauxiliary spraycanbeusedtocontrolRCSpressure.
Whenoverfilloftherupturedsteamgenerator occurs,aswithCase1,guideline ES-3.1POST-SGTR COOLDOWNUSINGBACKFILLisassumedtobeused.ThehighlevelactionsforES-3.1aresimilartoES-3.3.However,themethodbywhichES-3.1instructs theoperatortodepressurize therupturedsteamgenerator differsfromES-3.3.InGuideline ES-3.1theRCSisdepressurized topromotebackflowthroughthefailedtubewhichdepressurizes therupturedsteamgenerator withoutsteamreleasestotheatmosphere.
4.CooldowntoColdShutdownWhenRCStemperature andpressurehavebeenreducedtotheRHRsystemin-service values,RHRsystemcoolingisinitiated tocompletethecooldowntocoldshutdown.
Whencoldshutdownconditions areachieved, thepressurizer canbecooledtoterminate theevent.1074v:1O/112087 36 WESTINGHOUSE PROPRIETARY CLASS2F.1Methodology forCalculation ofMassReleasesTheoperatoractionsfortheSGTRrecoveryuptothetermination ofprimarytosecondary leakagearesimulated intheLOFTTR2analyses.
Thus,thesteamreleasesfromtherupturedandintactsteamgenerators, thefeedwater flowstotherupturedandintactsteamgenerators, andtheprimarytosecondary leakageintotherupturedsteamgenerator weredetermined fromtheLOFTTR2resultsfortheperiodfromtheinitiation oftheaccidentuntiltheleakageisterminated.
L2,CFollowing thetermination ofleakage,theoperators areassumedtocompletethestepsintheE-3andES-3.3orES-3.1guidelines toprepareforcooldowntocoldshutdown.
Thetimefromleakagetermination untiltheinitiation ofcooldownwasassumedtobe20minutes(seeReference 2).Theassumedtimeof20minutestoinitiatethecooldownisconsidered tobeconservative, sincetheactualtimeisexpectedtobelongerforanactualeventbecauseanevaluation ofthepotential offsiteradiation doseswouldberequiredpriortousingthesteamdumpmethodforthepost-SGTR cooldown.
ItwasassumedthattheRCSandintactsteamgenerator conditions aremaintained stableduringthe20minuteperioduntilthecooldownisinitiated.
ThePORVfortheintactsteamgenerator wasthenassumedtobeusedtocooldowntheRCStotheRHRsystemoperating temperature of332'F,atthemaximumallowable cooldownrateof100'F/hr..
TheRCSandtheintactsteamgenerator temperatures at2hourswerethendetermined usingtheRCSandintactsteamgenerator parameters atthetimeofleakagetermination andtheRCScooldownrate.'hesteamreleasesandthefeedwater flowsfortheintactsteamgenerator fortheperiodfromleakagetermination until2hoursweredetermined fromamassandenergybalanceusingthecalculated RCSandintactsteamgenerator conditions atthetimeofleakagetermination andat2hours.Thecoredecayheatandtheheataddedfromtheoperation ofoneRCPwereincludedintheenergybalanceforthistimeperiod.Sincetherupturedsteamgenerator isisolated, nochangeintherupturedsteamgenerator conditions isassumedtooccuruntilsubsequent depressurization.
Theassumptions ofareasonably shortpreparation timeforcooldownandthemaximumcooldownrateresultinminimumRCSandsteamgenerator temperatures at2hours,andtherefore, aconservative estimateofthesteamreleasedtotheatmosphere duringthefirst2hours.1074v:1D/112087 37 HESTINGHOUSE PROPRIETARY CLASS2a,c'TheRCScooldownwasassumedtobecontinued after2hoursuntiltheRHRsystemin-service temperature of332'Fisreached.Depressurization oftherupturedsteamgenerator wasthenassumedtobeperformed immediately following thecompletion oftheRCScooldown.
Therupturedsteamgenerator wasassumedtobedepressurized totheRHRin-service pressureof343psiaviasteamreleasefromtherupturedsteamgenerator PORV,sincethismaximizes thesteamreleasefromrupturedsteamgenerator totheatmosphere whichisconservative fortheevaluation oftheoffsiteradiation doses.TheRCSpressureisalsoassumedtobereducedconcurrently astherupturedsteamgenerator isdepressurized tominimizeflowbetweentheRCSandtherupturedsteamgenerator.
Itisassumedthatthecontinuation oftheRCScooldownanddepressurization toRHRoperating conditions arecompleted within8hoursaftertheaccidentsincethereisampletimetocompletetheoperations duringthistimeperiod.Thesteamreleasesandfeedwater flowsfrom2to8hoursweredetermined fortheintactsteamgenerator fromamassandenergybalanceusingtheRCSandsteamgenerator conditions at2hoursandattheRHRsystemin-service conditions.
Thecoredecayheatandtheheatadditionduetotheoperation ofoneRCPwerealsoincludedintheenergybalanceforthistimeinterval.
Thesteamreleasedfromtherupturedsteamgenerator from2to8hourswasdetermined.
based'namassandenergybalancefortherupturedsteamgenerator usingtheconditions atthetimeofleakagetermination andsaturated conditions attheRHRin-service pressure.
After8hours,itisassumedthatfurtherplantcooldowntocoldshutdownaswellaslong-term coolingisprovidedbytheRHRsystem.Therefore, thesteam~releasestotheatmosphere areterminated afterRHRin-service conditions areassumedtobe.reachedat8hours.F.2HassReleaseResultsThemassreleasecalculations wereperformed forbothsinglefailurecasesusingthemethodology discussed above.Forthetimeperiodfrominitiation oftheaccidentuntilleakagetermination, thereleasesweredetermined fromtheLOFTTR2resultsfortwoseparateperiodsforuseinthedosecalculations.
Thefirsttimeperiodconsidered isfromaccidentinitiation untilreactortrip.Sincethecondenser isinserviceuntilreactortrip,anyradioactivity 1074v:1D/112087 38 WESTINGHOUSE PROPRIETARY CLASS2releasedtotheatmosphere priortoreactortripwillbethrough'he condenser airejector.Afterreactortrip,'hereleasestotheatmosphere areassumedtobeviathesteamgenerator PORVs.Themassreleasescalculated fromthetimeofleakagetermination until2hoursandfrom2-8hoursarealsoassumedtobereleasedtotheatmosphere viathesteamgenerator PORVs.ThemassreleasesfortheSGTRevent[assuming delayeduseoftheintactsteamgenerator PORV]'Case1)arepresented inTableII.5.Theresultsindicatethatapproximately
[21,990]'bmofsteamand[23,710]'bmofwaterisreleasedfromtherupturedsteamgenerator totheatmosphere inthefirst2hours.Atotalof[129,300]
'bmofprimarywateristransferred tothesecondary sideoftherupturedsteam.generator beforethebreakflowisterminated.
ThemassreleasesfortheSGTReventassuming[failureandisolation oftherupturedsteamgenerator PORV]'Case2)arepresented inTableII.6.Theresultsindicatethatapproximately
[62,480]'bmofsteamisreleasedtotheatmosphere fromtherupturedsteamgenerator withinthefirst2hours.After2hours[33,300]'bmisreleasedtotheatmosphere fromtherupturedsteamgenerator.
Atotalof[172,800]
'bmofprimarywateristransferred tothesecondary sideoftherupturedsteamgenerator beforebreakflowisterminated.
1074v:1D/112087 39 MESTINGHOUSE PROPRIETARY CLASS2TABLEII.5CASE1MASSRELEASES0-TRIPTOTALMASSFLOW(POUNDS)TIMEPERIODTRIPTMSEP-OVFILL-TTBRK-T2HRSTMSEPOVFILLTTBRKT2HRS'RHRFaultedSGCondenser Atmosphere Feedwater 47,80000015,450654043,60030,50000023,710*'00PICIntactSGCondenser Atmosphere 47,150Feedwater47,1500000014,73032,95013,450151,870505,50046,04029,61017,900158,700513,500BreakFlow421647,57453,71023,800TRIPTMSEPOVFILLTTBRKT2HRSTRHR=Timeofreactortrip=[50]'ec.=Timewhenwaterreachesthemoistureseparators
=[1086]'ec.=Timewhensteamgenerator overfills
=[2372]'ec.=Timewhenbreakflowisterminated
=[3428]'ec.=Timeat2hours=7200sec.=TimetoreachRHRin-service conditions, 8hours=28,800sec.*Ha'ter1074v:1D/1120Sl 40 MESTINGHOUSE PROPRIETARY CLASS2TABLEII.6CASE2MASSRELEASES~TOTALMASSFLOM(POUNDS)TIMEPERIOD0-TRIPTRIPTMSEP"TTBRK-T2HRSTMSEPTTBRKT2HRSTRHRFaultedSGCondenser Atmosphere Feedwater 46,8800062,09039042,74033,260033,300CL,CIntactSGCondenser Atmosphere Feedwater 46,220000035,43018,450153,920457,00046,22097,78019,700160,300457,700BreakFlow4134132,66636,00000TRIP=TimeTMSEP=TimeTTBRK=TimeT2HRS=TimeTRHR=Timeofreactortrip=[49.4]'ec.whenwaterreachesthemoistureseparators
=[2372]'ec.whenbreakflowisterminated
=[3438]'ec.at2hours=7200sec.toreachRHRin-service conditions, 8hours=28,800sec.1074v:1D/112087 41 MESTINGHOUSE PROPRIETARY CLASS2TABLEII.7SUMMARIZED MASSRELEASESTOTALMASSFLOM(POUNDS)CASE1CASE2FaultedSG0-TTBRKTTBRK-2HRS-2HRS8HRS0-TTBRK-2HRSTTBRK2HRS8HRSCondenser 47,82046,880Atmosphere 45,700*62,48033,300Feedwater 74,10076,000IntactSGCondenser 47,15046,2200Atmosphere 61,130151,870505,500Feedwater 122,800158,700513,50053,880153,920457,000163,700160,300.457,700BreakFlow129,3000172,800023,710ibmofthisiswater.1074v:10/1120S7 42 WESTINGHOUSE PROPRIETARY CLASS2III.RADIOLOGICAL CONSEQUENCES ANALYSISTheevaluation oftheradiological consequences ofasteamgenerator tuberupture,assumesthatthereactorhasbeenoperating attheproposedTechnical Specification limitforprimarycoolantactivityandattheexistingTechnical Specification limitforprimarytosecondary leakageforsufficient timetoestablish equilibrium concentrations ofradionuclides inthereactorcoolantandinthesecondary coolant.Radionuclides fromtheprimarycoolantenterthesteamgenerator, viatherupturedtube,andarereleasedtotheatmosphere throughthesteamgenerator safetyorpoweroperatedreliefvalvesandviathe4condenser airejector,exhaust.Thequantityofradioactivity releasedtotheenvironment, duetoaSGTR,dependsuponprimaryandsecondary coolantactivity, iodinespikingeffects,primarytosecondary breakflow,breakflowflashingfractions, attenuation ofiodinecarriedbytheflashedportionofthebreakflow,partitioning ofiodinebetweentheliquidandsteamphases,themassoffluidreleasedfromthegenerator andliquid-vapor partitioning intheturbinecondenser hotwell.Alloftheseparameters wereconservatively evaluated foradesignbasisdoubleendedruptureofasingletube.A.'esinBasisAnalticalAssumtionsThemajor'assumptions andparameters usedintheanalysisareitemizedinTable111.1.Thefollowing isadiscussion ofthesourceterm.SourceTermCalculations Theradionuclide concentrations intheprimaryandsecondary system,priortoandfollowing theSGTRaredetermined asfollows:a.Theiodineconcentrations inthereactorcoolantwillbebaseduponpreaccident andaccidentinitiated iodinespikes.1074v:1D/112087 43 MESTINGHOUSE PROPRIETARY CLASS2AccidentInitiated Spike-Theinitialprimarycoolantiodineconcentration is1yCi/gmofDoseEquivalent (D.E.)I-131.Following theprimarysystemdepressurization associated withtheSGTR,aniodinespikeisinitiated intheprimarysystemwhichincreases theiodinereleaseratefromthefueltothecoolanttoavalue500timesgreaterthanthereleaseratecorresponding totheinitialprimarysystemiodineconcentration.
Thedurationofthespike,[3.31'ours,issufficient toincreasetheinitialRCSI-131inventory byafactorof[100]'ii.Preaccident Spike-Areactortransient hasoccuredpriortotheSGTRandhasraisedtheprimarycoolantiodineconcentration from1to60yCi/gramofD.E.I-131.b.Theinitialsecondary coolantiodineconcentration is0.1yCi/gramofD.E.I-131.c.Thechemicalformofiodineintheprimaryandsecondary coolantisassumedtobeelemental.
4DoseCalculations Thefollowing assumptions andparameters wereusedtocalculate theactivityreleasedtotheatmosphere andtheoffsitedosesfollowing aSGTR.1.Themassofreactorcoolantdischarged intothesecondary systemthroughtheruptureandthemassofsteamreleasedfromtheintactandrupturedsteamgenerators totheatmosphere arepresented inTableII.5andII.G.2.Thetimedependent fractionofruptureflowthatflashestosteamandisimmediately releasedtotheenvironment ispresented inFigureIII.1.3.Thetimedependent iodineremovalefficiency forscrubbing ofsteambubblesas'heyrisefromtheleaksite[(assumed tobeatthetopofthetubebundle)]'othewatersurfacewasalsodetermined foreach,1074v:10/112087 MESTINGHOUSE PROPRIETARY CLASS2case.,Theiodineremovalefficiency isdetermined bythe.methodsuggested byPostmaandTam(Ref.6).Theiodineremovalefficiencies areshowninFigureIII.2.4.The0.2gpmprimarytosecondary leakisassumedtobesplitevenlybetweenthesteamgenerators.
5.Theiodinepartition factorbetweentheliquidandsteamoftherupturedandintactsteamgenerators isassumedtobe1DO.6.Nocredit'as takenforradioactive decayduringreleaseandtransport, orforclouddepletion bygrounddeposition duringtransport tothesiteboundaryorouterboundaryofthelowpopulation zone.7.Short-term atmospheric dispersion factors(x/gs)foraccidentanalysisandbreathing ratesareprovidedinTableIII.4.Thebreathing rateswereobtainedfromNRCRegulatory Guide1.4,(Ref.4).OffsiteThroidDoseCalculation ModelOffsitethyroiddosesarecalculated usingthe~uation:ThgtDCF,.g(IAR);.(BR).(x/()).]1Jwhere(IAR)..=integrated activityofisotopeireleasedduring'the 1Jtimeintervalj'nCi>>F*Nocreditistakenforclouddepletion bygrounddeposition orbyradioactive decayduringtransport totheexclusion areaboundaryortotheouterboundaryofthelow-population zone.1074v:1D/112087 45 WESTINGHOUSE PROPRIETARY CLASS2(BR)~breathing rateduringtimeinterval' inmeter/second(TableIII.4)(x/Q)=atmospheric dispersion factorduringtimeintervaljJinsecond/meter (TableIII.4)(DCF).=thyroiddoseconversion factorviainhalation for1isotopeiinrem/Ci(TableIII.5)thyroiddoseviainhalation inremResultsThyroiddosesattheExclusion AreaBoundaryandLowPopulation Zonearepresented inTableIII.6.Alldosesarewellwithintheallowable guidelines asspecified byStandardReviewPlan15.6e3and10CFR100.
1074v:1D/112487 46 WESTINGHOUSE PROPRIETARY CLASS2TABLEIII.1PARAMETERS USEDINEVALUATING THERADIOLOGICAL CONSEQUENCES OFASTEAMGENERATOR TUBERUPTUREI.SourceDataA.Corepowerlevel,MWt1520B.Totalsteamgenerator tubeleakage,priortoaccident, gpm0.2C.Reactorcoolantiodineactivity:
1.AccidentInitiated SpikeTheinitialRCiodineactivities basedon1I>Ci/gramofD.E.I-131arepresented inTableIII.3.Theiodineappearance ratesassumedfortheaccidentinitiated spikearepresented inTableIII.2.2,Pre-Accident SpikePrimarycoolantiodineactivities basedon60gCi/gramofD.E.I-131arepresented inTableIII.3.,D.Secondary systeminitialactivityDoseequivalent of0.1yCi/gmofI-131,presented inTableIII.3.1074v:1D/112087 47 HESTINGHOUSE PROPRIETARY CLASS2TABLEIII.l(Sheet2)E.Reactorcoolantmass,gramsF.Steamgenerator mass(each),grams1.27x103.39x10G.Offsitepow'erLostattimeofreactortripH.Primary-to-secondary leakagedurationforintactSG,hrs.I.Speciesofiodine100percentelemental II.ActivityReleaseDataA.Faultedsteamgenerator 1.Ruptureflow2.RuptureflowflashingfractionSeeTableII.5orII.GSeeFigureIII.13.Iodinescrubbing plusmoistureseparator removalefficiency SeeFigureIII.24.Totalsteamrelease,lbsSeeTableII.5orII.G5.Iodinepartition factora.Priortooverfillb.Afteroverfill100-1.0-SeeFigureIII.36.Locationoftuberupture[TopofBundle]'074v:10/1120S748 MESTINGHOUSE.PROPRIETARY CLASS2TABLEIII.1(Sheet3)B.Intactsteamgenerator 1.Primary-to-secondary leakage,gpm0.12.Totalsteamrelease,lbsSeeTable11.5or11.63.Iodinepartition factor100C.Condenser 1.Iodinepartition factor100D.Atmospheric Oispersion FactorsSeeTableIII,41074v:lo/112087 49 MESTINGHOUSE PROPRIETARY CLASS2TABLEIII.2IODINESPIKEAPPEARANCE RATES(CURIES/SECOND) 1-1323-133I"1340.942.221.743.071074v:1D/112087 50 MESTINGHOUSE PROPRIETARY CLASS2TABLEIII.3IODINESPECIFICACTIVITIES IN(yCi/gm)THEPRIMARYANDSECONDARY COOLANTBASEDON1,60AND0.1yCi/gramOFD.E.I-131Nuclide~Pit11~luCD/m60uCi/cDmSecondarCoolant0,1wCi/(1m0.7947.10.079I-1320.3520.70.0351.0160.70.1010.2012.20.020I-1350.7947.10.0791074v:1D/1 1208751 MESTINGHOUSE PROPRIETARY CLASS2TABLEIII.4ATMOSPHERIC DISPERSION FACTORSANDBREATHING RATESTimeExclusion AreaBoundaryLowPopulation (hours)x/Q(Sec/m)3Zonex/Q(Sec/m)3Breathing Rate(m/Sec)[4]0-22-84.8x103x103x103.47x103.47x101074v:1D/112087 52 WESTINGHOUSE PROPRIETARY CLASS2TABLEIII.5THYROIDDOSECONVERSION FACTORS(Rem/Curie)
[51Nuclide~I-131I-1341.49x101.43x102.69x103.73x105.60x101074v:1D/112087 53 NESTINGHOUSE PROPRIETARY CLASS2TABLEIII.6RESULTSOosesRemAllowable Case1Case2Guideline Valuel.AccidentInitiated IodineSikeExclusion AreaBoundary(0-2hr.)Thyroid26.43.830LowPopulation Zone(0-8hr.)Thyroid1.70.3302.Pre-Accident IodineSikeExclusion AreaBoundary(0-2hr.)Thyroid102.122.1300,LowPopulation Zone(0-8hr.)Thyroid6.41.4300~1074v:1D/112487 54 WESTINGHOUSE PROPRIETARY CLASS2GINN4SGTRIS%TUBEPLUGGING-C4SER4OIOLOGIC4L CONSEOUENCES EV4LU4TION BREAKFLOWFL4SNINGFR4CTION~ISCase1e.~It~Si,tt&~tt~S4,lt~SiTIICItttlGINN4SGTRISZTUBEPLUGGINGCASE2R4OIGLOOICALCONSEOUENCES EVALUATIONBREAKFLOWFLASHINGFR4CTION~ISCase2~ItH,tt14~StSI,ateiTletItttIFigureIII.1BreakFlowFlashingFraction1074v:1D/112087 55 HESTINGHOUSE PROPRIETARY CLASS2GL,GCASE1o5~2081eeeTINE(SECONDS) 1588288~5CASE24Z.(~2VM'I01088TINEISECONDSI 1508288FigureIII.2SrubbingEfficiency 1074v:1D/112087 WESTINGHOUSE PROPRIETARY CLASS2IE+2CASE11E+120~aC<LE+8ZIHE(HOURS)1.5JE+2CASE21E+120CC+IE+8TIHE(HOURS)FigureIII.3FaultedSGIodinePartition Factors1074v:1D/112087 57 WESTINGHOUSE PROPRIETARY CLASS2IV.CONCLUSION Thepotential radiological consequences ofasteamgenerator tubefailurewereevaluated fortheR.E.Ginnanuclearpowerplanttodemonstrate thattheuseoftheStandardTechnical Specification (STS)primarycoolantactivitylimitof1yCi/gramofdoseequivalent I-131willresult.inoffsitedosesthatarewithintheappropriate guidelines, Themassreleasesforadesignbasisdoubleendedruptureofasingletubewithalossofoffsitepowerwereconservatively calculated usingthecomputercodeLOFTTR2.Twocaseswereconsidered:
[1)intactsteamgenerator PORVfailsclosedandmustbelocally1opened,and2)rupturedsteamgenerator PORVfailsopenandmustbelocallyisolated.]
'heanalysisexplicitly modeledthetimeneededforthe'perators toperformtherecoverystepsoutlinedinguideline E-3ofRevision1oftheWestinghouse OwnersGroupEmergency ResponseGuidelines.
Theresulting dosesattheexclusion areaboundaryandlowpopulation zonearewithintheallowable guidelines asspecified byStandardReviewPlan15.6.3andlOCFR100.
Consequently, theSTSprimarycoolantactivitylimitissufficiently lowtoensurethattheradiological consequences ofasteamgenerator tuberuptureattheR.E,Ginnaplantwillbewithintheguidelines.
1074v:1D/112087 58 HESTINGHOUSE PROPRIETARY CLASS2V.REFERENCES 1.Lewis,Huang,Behnke,Fittante, Gelman,"SGTRAnalysisMethodology toDetermine theMargintoSteamGenerator Overfill,"
HCAP-10698-P-A, August1987.[PROPRIETARY'.
Lewis,Huang,Rubin,"Evaluation ofOffsiteRadiation DosesforaSteamGenerator TubeRuptureAccident,"
Supplement 1toHCAP-10698-P-A, March1986.[PROPRIETARY]
3.R.Elaisz,LetterfromRGEtoHestinghouse concerning GinnaspecificoperatoractiontimesforSGTRanalysis, February7,1985.4.NRCRegulatory Guide1.4,Rev.2,"Assumptions UsedforEvaluating thePotential Radiological Consequences ofaLOCAforPressurized HaterReactors",
Jun'e1974.5.NRCRegulatory Guide1.109,Rev.1,"Calculation ofAnnualDosestoManFromRoutine,ReleasesofReactorEffluents forthePurposeofEvaluating Compliance with10CFRPart50AppendixI",October1977.6.Postma,A.K.,Tam,P.S.,"IodineBehaviorinaPHRCoolingSystemFollowing aPostulated SteamGenerator TubeRupture",
1074v:1D/120487 59 IraV0;Jih