Text

Use of Lake Ontario Water in Steam Generators During Hot Shutdown.
	ML17309A190
Person / Time
Site:	Ginna
Issue date:	02/28/1981
From:	COPLEY S E, LEIBOVITZ J, PEARL W L; NWT CORP.
To:	;
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ML17309A169	List: ML17309A168; ML17309A190;
References
	NWT-167, NUDOCS 8106300308
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I1iliceÃuelzvROCHESTERGAS"h.704KANDELECTRICCORPORATIONo89EASTAVENUE,ROCHESTER,N.Y.14649JOHNE.MAIERVICEPRESIDENTJune23,1981TEt.EPHONEARE*COOE7IOi54g27000I<ll~,j=6'>'/4IDirectorofNuclearReactorRegulationAttention:Mr.DennisM.Crutchfield,ChiefOperatingReactorsBranch55U.S.NuclearRegulatoryCommissionWashington,D.C.20555

Subject:

SEPTopicsV-10.B,V-11.A,V-11.B,VI-7.C.1,VII-3,andVIII-2,R.E.GinnaNuclearPowerPlantDocketNo.50-244

References:

(1)LetterfromDennisM.Crutchfield,NRC,toJohnE.Maier,RGE,SEPTopics,V-10.B,V-ll.B,andVII-3(SafeShutdownSystemsReport),May13,1981.(2)LetterfromDennisM.Crutchfield,NRC,toJohnE.Maier,RGE,SEPTopicsV-11.A,V-11.B,andVI-7.C.1,datedApril24,1981.(3)LetterfromDennisM.Crutchfield,NRC,toJohnE.Maier,RGE,SEPTopicsVII-3andVIII-2,datedApril2,1981.

DearMr.Crutchfield:

ThisletterisinresponsetotheSEPtopicassessmentsprovidedinthethreeabove-referencedletters.Duetotheintimaterelationshipofthe"SafeShutdown"topicsV-10.B,V-ll.A,V-11.BandVII-3addressedinthesethreeletters,allofourcommentsareprovidedconcurrentlyinthethreeattachedresponses.ThisshouldaidtheinclusionofourcommentsintotheNRC's"SEPIntegratedAssessment".AttachmentsVerytrulyyours,ohnE.Maier+~aili Attachment1:RGKEresponsestoNRCAssessmentofSEPTopicsV-10.B,RHRSystemReliability,V-ll.B,RHRInterlockRequirements,andVII-3,SystemsRequiredforSafeShutdown(SafeShutdownSystemsreport),May13,1981.InRG6E'sJanuary13,1981responsetotheNRC'sNovember14,1980"SafeShutdownSystems"assessment,anumberofcommentsweremadewhichhavenotbeenincorporatedintoRevision2ofthisassessment,transmittedbyletterdatedMay13,1981.Wefeelthesecommentswerevalid,andshouldbeincorporated.Forcontinuity,thesecommentswillbelistedbelow(withtheiroriginalcommentnumbers):Onpage5,PiinSstemPassiveFailures,theNRCassumespipingsystempassivefailures"...beyondthosenormallypostulatedbythestaff,e.g.,thecatastrophicfailureofmoderateenergysystems...".Althoughitisshownthatsafeshutdownfollowingsuchaneventcouldbeachieved,itisnotconsideredthatsuchanevaluationshouldevenbemade.Asnotedbythestaff,itisclearlybeyondareasonabledesignbasis.Itisthusrecommendedthatthisparagraphbedeletedfromtheevaluation.Subsequentevaluationstothis"criterion",suchasthoserelatedtotheCCWsystemonpage22and23,shouldalsobedeleted.Inparagraphgonpage66,itisnotedthat,whenapplyingthepowerdiversityrequirementsofBTPASB10-1ineventofanSSE,nomeanstosupplyfeedtothesteamgeneratorsexists.Itwasdeterminedthatthiswasacceptable,basedonlowlikelihoodofoccurrence.Thisconclusioniscorrect;however,sinceBPTASB10-1doesnotconsideranSSEinconjunctionwiththelossofallA.C.power,thereisnoneedtoevenmaketheevaluation.ThecomparisonsintheSEPprogramshouldbetocurrentcriteria,ratherthantoarguableextrapo-lations.ReferencetolossofallA.C.powerinconjunctonwithanSSEshouldthusbedeletedfromthisparagraph.12.OnpageA-4,itisnotedthatadditionalsystemsarerequiredtoachievecoldshutdownforaPWRthanforaBWRbecauseofadifferenceinthedefinitionofcoldshutdown.Thisdoesnotappeartobeareasonablebasis.Systemrequirementsshouldbebasedonspecificsafetyreasons.TheNRCshouldbeconsistentinitsrequirementsforcoldshutdown,orprovideatechnicalbasisforanydifferences."

~f7 Staffposition1statesthat"thelicenseemustdevelopplantoperating/emergencyproceduresforconductingaplantshutdownandcooldownusingonlythesystemsandequipmentidentifiedinSection3.1oftheSEPSafeShutdownSystemsReport."RGsEdisagreeswiththeneedfortheseprocedures.WereiteratethecommentsprovidedinourJanuary13,1981responsethattheoperatorshouldperformacooldownwiththebestequipmentavailabletohimatthetime.Ifapieceofnon-safetyequipmentisavailable,andwouldbethemostbeneficialforperformingarequiredfunction,itisexpectedthatthispieceofequipmentwouldbeused.Ifitisnotavailable,theoperatorcouldfallbackontheuseofsafety-gradeequipment.ButRGGEdoesnotintendtocommitplantpersonneltouseonlysafety-relatedequipment,ifnon-safetyequipmentisavailableandmoreeffective.Wefeelthatitwouldbeimpossibletodeterminewhena"safety-grade-only"cooldownprocedurewouldeverbeimplemented.Aslongasthesafety-gradeequipmentisavailable(andthesafeshutdownassessmentconcudesthatitis),RGSEconsidersthatthenecessarysafetyrequirementsaremet.RGSEalsonotesthatnoregulatorybasisforthisrequirementisprovided.ItisadmittedinSection4.5oftheSafeShutdownreportthat"theneedforproceduresfortheseevaluationsisnot,identifiedinRegulatoryGuide1.33...".Section4.5thengoesontosaythatthebasisisfoundinBTPRSB5-1andSEPTopicVII-3.ButBTPRSB5-1merelyreferencesRG1.33,andthisistheassessmentofSEPTopicVII-3.Therefore,sincenobasisforthis"requirement"exists,andwedonotfeelthatitwouldevenbebeneficial,andsincetheSafeShutdownreportdidconcludethatthecapabilityforattainingcoldshutdownusingonlysafety-relatedequipmentexists,RG&Econcludesthatthisstaffpositionshouldbedeletedfromconsideration.Staffposition3doesnotappeartotakeintoaccounttheinformationprovidedinourMarch27,1981submittalregardingSEPTopicV-11.A.Enclosure3tothatsubmittalprovidesthevalveequipmentspecification,notingthatthe700,701,720and721MOV'saredesignedsuchthattheyphysicallyareunabletoopenagainstadifferentialpressureofgreaterthan500psi.ThisensuresthatanintersystemLOCAcausedbytheopeningoftheoutboardvalves,plusleakageoftheinboardvalves,cannotoccur,sincetheoutboardvalvescannotopen.

Evenwithoutthisprovision,itisdifficulttocomprehendhowtheGinnaarrangementcouldresultinan"EventV".Byadministrativeprocedure,theRHRvalvesarekey-lockedclosed,withpowerremoved.Further,interlocksareprovidedfortheinboardRHRvalves.Thus,foran"EventV"tooccurwouldrequirethe:1)failureoftheadministrativeprocedurerequiringpowerlock-out(atthebreaker),2)failureoftheadministrativeproceduregoverningoperationofthevalveatpower,3)failureoftheinboardisolationvalve,4)failureofthereliefvalve(RV203)whichhasacapacityof70,000lb/hratits600psigsetpoint,torelievetheleakagepasttheinboardRHRvalve.Thissetoffailuresisconsideredveryremote.WhencoupledwiththefactthattheRHRvalvedesignpreventsopeningofthevalvesagainstagreaterthan500psidifferentialpressure,itisRGEE'sconclusionthatthepossibilityofanintersystemLOCAshouldnotbeacredibledesignbasis.Noadditionalmodifications,suchasdiverseinterlocksfortheoutboardvalves,arewarranted.Staffposition5statesthat"theoperatingproceduresfortheGinnaplantshouldbemodifiedtodirecttheoperatortocooldownanddepressurizetoRHRinitiation.parameterswithin36hourswhenevertheServiceWaterSystemisusedforsteamgeneratorfeedwater..."ThispositionisbasedonthereferenceBNL-NUREG-28147,"ImpureWaterinSteamGeneratorsandIsolationCondensers."WehavehadthisreportreviewedbyNWTCorporation.NWT-167,"UseofLakeOntarioWaterinSteamGeneratorDuringHotShutdown"(attached)concludesthat,"althoughnotrecommendedfromthestandpointofmaximizingcomponentlife,andoperationforperiodsuptoseveraldaysisnotexpectedtoresultinanysignificantcrackingorindeteriorationofsteamgeneratorintegrity."RG&EthereforeconcludesthataspecificdirectivetocooldownanddepressurizetoRHRinitiationconditionsisnotwarranted,andshouldnotbeincludedinaprocedure.Thecapabilitytodothisdoesexist,however,andcouldbeusedifdeterminedtobenecessaryatthetime.

l\J"v1v~Jl Attachment2:RG&EresponsestoNRCletterofApril24,1981regardingSEPTopicsV-11.A,"IsolationofHighandLowPressureSystems",V-11.B,"RHRInterlockRequirements",andVI-7.C.1,"IndependenceofRedundantOnsitePowerSystems".1.TheSafetyEvaluationforSEPTopicV-11.A,"RequirementsforIsolationofHighandLowPressureSystems",specifiesthattheoutboardRHRvalvesshouldhavediverseinterlockstopreventopening.whentheRCSpressureisgreaterthanRHRsystemdesignpressure.RGGErationalefornotprovidingtheseadditionalinterlocksisprovidedincomment3ofAttachment1ofthistransmittal.2.ThesafetyevaluationalsorequiredthatinterlocksbeinstalledontheCVCSsuctionvalves(200A,200B,202),topreventapossibleoverpressurizationoftheCVCSletdownlineoutsidecontainment.RGEEhasnotedinourMarch27,1981letteronthisSEPTopicthatareliefvalve(RV203),withacapacitygreaterthanthecombinedcapacityofthethreeorifices,wouldrelievethepressurebuildupcausedbyclosureofthecontain'mentisolationvalve'71.NooverpressurizationoftheCVCSwouldthusbeexpected.RGGEhasalsoevaluatedthepotentialconsequencesofsuchanoverpressurizationevent,withasubsequentsmallLOCAoutsidecontainment,anddeterminedthatnounacceptableconsequenceswouldresult.ThisbreakwouldbeasmallLOCAoutsidecontainment(maximumflowof140gpm),andwouldbeterminatedbyclosureofvalves200A,200B,and202eitherbyoperatoractionorautomaticallybylowpressurizerlevel.Radiologicalconsequenceswouldbeminimal,sincenofueldamagewouldresult.Thiseventisspecificallyevalu-atedbySEPTopicXV-16,"RadiologicalConsequencesofFailureofSmallLinesCarryingPrimaryCoolantOutsideContainment."RG&EhasprovidedinformationconcerningthistopicbyletterdatedJune18,1980fromL.D.WhiteJr.toMr.DennisM.Crutchfield.TheRG&Econclusionisthat,basedontheavailabilityofRV203topreventoverpressurization,togetherwiththelackofunacceptableconsequencesduetoanoverpressurization,nointerlocksorothermodificationsarerequiredfortheCVCSsuctionvalves.3.ThesafetyevaluationfurtherstatesthatpositionindicationisrequiredontheCVCSdischargecheckvalves.AsstatedinourMarch27,1981letteronSEPTopicV-11.A,wedonotbelievethatthislineshouldbeclassifiedasalowpressure I

systemconnectedtotheRCS,sincethepipingis2500-1bpipingthroughoutitslength(tothepositivedisplacementchargingpump).RG&Ehashadnoexperiencewith'ailuresofthepositivedisplacementchargingpumppistonstoholdprimarysystempressure,norwouldanyfailuresbeanticipated.OurcontentionthatthecharginglineisnotalineofconcernisborneoutbyamemofromEdsonG.CasetoRaymondF.Fraley,"IsolationofLowPressureSystemsfromReactorCoolantSystem",datedJuly11,1977.ThatlettertransmittedanNRCstudyofthissubjecttotheACRS,andevaluatedallpotentiallinesofconcern.Thecharginglinewasnotincluded.Toverifythatthecharginglinewasnotavalid"EventV"concern,RG&EcalculatedthePWRCheckValveEventTree(Section4.4ofNASH-1400),usingthecharginglinecon-figuration(twoin-seriescheckvalvesandachargingpumppiston).Veryconservativelyassumingthatbothcheckvalveswereundetectedopen,andthattheprobabilityofthechargingpump~istonfailurewasequaltoacheckvalvefailure,theQUMcalculatedforthisconfigurationwasdeterminedtoSe1.4x10/year.Thisisalowenoughvaluetoobviouslybeofnoconcern.RG&Ethereforeconsidersthatcheckvalvepositionindi-cationisnotneededonthecharginglinecheckvalves.WithrespecttotheSEPTopicAssessmentV-11.B,nocommentsarenecessary,sincetheresolutionofoutstandingissuesisaddressedinthetopicassessmentforSEPTopicV-11.A.TheadditionalinformationrequestedforSEPTopicVI-7.C.1ispresentlybeingdeveloped.ItisanticipatedthatthisinformationcanbefurnishedtotheNRCbyJuly15,1981.

lLJ Attachment3:RGEEresponsestoNRCletterofApril2,1981,concerningSEPTopicsVII-',"Electrical,Instru-mentation,andControlFeatureofSystemsRequiredforSafeShutdown",andVIII-2,"DieselGenerators".ItappearsthatallcommentsprovidedbyRG&EinourJanuary23,1981andJanuary30,1981lettersconcerningthesetopicshavebeenproperlyincorporated.Basedontheresolutionofallopenitems,andtheremovalofdieselgeneratortestingfromSEPTopicVIII-2,RGEEconcludesthatbothofthesetopicsarecomplete,withnooutstandingissuestobecarriedintotheIntegratedAssessment.

0IHitLNIPI NWT167February1981USEOFLAKEONTARIOWATERINSTEAMGENERATORSDURINGHOTSHUTDOWNW.L.PearlS.E.CopleyJ.LeibovitzPreparedforRochesterGas&ElectricCompanyCorporation7015REALMDRIVE,SANJOSE,CALIFORNIA95119 0'I ThisdocumentwaspreparedfortheRochesterGas&ElectricCompany.NeithertheNWTCorporationnoranypersonactingonitsbehalfassumesanyresponsibilityforliabilityordamagewhichmayresultfromtheuseofanyinformationdisclosedinthisdocument.I1h'!'~,1zf'))

INTRODUCTIONThepossibilityofusingLakeOntariowaterasanemergencyPWRfeedwatersupplyformorethan36hoursduringwhichtheplantwouldbebroughttocoldshutdownisbeingconsidered.Themaximumsteamingrateduringsuchaperiodwouldbe100,000pounds/h(200gpm)atatemperatureof350'F.Asa'consequenceofsteaming,impuritiesoftheuntreatedLakeOntariowaterwillconcentrateinthesteamgenerator.Ofmajorconcernisthepossibleriskofstresscorrosioncracking(SCC)ofsteamgeneratormaterialsincontactwiththeconcentratedsolutionthusformed.Toaddressthisconcern,thechemistryvariationintheliquidphaseassteamingproceedsat350'FwasestimatedwithemphasisonpH.Then,thepossiblepotentialforSCCwasassessedonthebasisoftheseestimatesandavailableSCCdata.

pHVARIATIONAT350'F'UPONSTEAMINGLAKEONTARIOWATERA.ComputerModelingThecompositionofLakeOntariowaterasdeterminedbyRGEisgiveninTablel.TABLE1LAKEONTARIOWATERANALYSISppmCalciumMagnesiumSodiumPotassiumAluminumChlorideSulfate"358133.60.13235NitratePhosphateFluorideSilica(asSi02)DissolvedOxygenAmmonia(asNitrogen)2.50.30.150.259.50.24Estimatesofthewaterchemistryvariationuponsteamingweredevelopedusingthefollowingassumptions:1.Sincealuminumandsilicaareins'toichiometricproportioninLakeOntariowater(Table1),theyareassumedtoprecipitateasaluminumsilicate(clay)uponconcentrating'andthereforeareremovedfromsolution.2.Sincecalciumoccursinthewater(Table1)inlargeexcessoverphosphate,itisassumedtoprecipitateallthephosphateascalciumhydroxyapatite(Ca5(P04)30H)andremoveitfromthesolution.Thecalciuminsolutionisdecreasedbythecorrespondingamount.3.Fluorideandnitriteareassumedtobehaveaschloride.Potassiumisassumedtobehaveassodium.4~Sodiumandchlorideinsolutionareassumedtoremaincompletelydissociated.5.Calciumcarbonateprecipitationisneglected.DegasificationofCO~bysteamingisassumedtooccur.

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6.Theconcentrationofsodiumandcalciumchloridesisassumedlimitedbyasolubilityof5molal.7.Chemicalequilibriumexpressionsofreferences2and3apply.Onthisbasis,theliquidsolutionpHvariationuponsteamingat350'Fwasestimatedasafunctionofconcentrationfactordefinedasthemassratiooftotalwater(steam+liquid)toliquidwaterresidual.TheresultsarepresentedgraphicallyinFigure1.ItisimportanttonotethatthedefinitionofpHusedhereisthatfollowedbyMesmer4inthedeterminationofthedissociationconstantofwaterathightemperatures,viz,thenegativeofthelogarithmofthehydrogenionconcentration(notofitsactivity).Similarly,neutralpHisdefinedasthatwherethehydrogenandhydroxylionconcentrationsaree'qual.ThisneutralpHisafunctionofionicstrength.Therefore,thepHvariationoftheconcentratedsolutionsmustbeconsideredinrelationtothatofneutralpH,alsoplottedinFigure1.Forbasicsolutionsasisthecaseconsideredhere,itisimportanttobearinmindthatthehydroxylionconcentrationisexpressedintermsofpHas'follows:10pH-2NpHOH(whereNpHistheneutralpHv'alue)andthatwhentheneutralpHvariestogetherwiththeionicstrengthastheliquidsolutionisbeingconcentrateduponsteaming,thebasicityofthesolutionmaynotbeappreciatedfromthesolutionpHalone.TheequivalentNaOHconcentrationismoresuitableforthispurposeandisplottedalsoinFigure1.B.DiscussionSteamGeneratorBulkWaterBasedon-'amaximumfeedrateof200gpmtothesteamgeneratorandatotalsteamgeneratorliquidvolumeofapproximately12,000gallons,amaximumofonesteamgeneratorvolumeissteamedawayeachhour.Therefore,undermaximumsteamingconditions,theconcentrationfactorachievedinthebulksteamgeneratorwaterist+1wheretisthenumberofhoursofsteaming.

10SolutionpHEquivalentNaOHConcentrationNeutralpH.400O300o2008lot101001000100000Time,hFigurel.VariationofSteamGeneratorpHwithSteamingat350'F(feedingLakeOntariowaterat200gpm) l-!tI, ThevariationwithtimeoftheequivalentsodiumhydroxideconcentrationinthesteamgeneratorwithsteamingofemergencyLakeOntariofeedwaterthencanbefollowedonFigurel.ItisseenthatamaximumequivalentNaOHconcentration'fabout300ppmwillbereachedinthesteamgeneratorbulkwaterwhen15to20steamgeneratorvolumeswillhavebeenconvertedto,steam,i.e.,inapproximatelytwentyhours.FurtherboilingshouldthendecreasetheequivalentNaOHconcen-trationasmagnesiumand/orcalciumhydroxidesand/orcalciumsulfateprecipitatewithincreasedconcentrating.Thedecreasereachesalimit(atabout20,000steamgeneratorvolumesconvertedtosteam,i.e.,in20,000hours)whensodiumandcalciumchloridesstarttoprecipitatealso.Thislimitisestimatedatabout100ppmequivalentNaOHforLakeOntariowatercompositionasspecifiedinTable1andwiththeassumptionsalreadystated.Theassumptionsseemreasonableand,atanyrate,canbetestedexperimentallywithasmallautoclavefromwhichknownamountsofLakeOntariowaterwouldbeboiledawayat350'Fatconstantliquidlevelintheautoclave.CrevicesTheestimatedequivalentNaOHsolutionconcentrationinsteamgeneratorcreviceswilldependupontherelativedegreeofcrevicesolutionconcentrationabovethebulkwater.Intubetotubesupportplatecrevices,theremaybeadistributionofrelativeconcentrationfactorsofunityandhigher.Thechemistryinacrevicewouldleadthatofthebulkinthesensethatthechemistryofaspecificcrevicewouldtravelthesamecurve(Figure1)asthebulkbutwouldbeatapointonthecurvesomewhataheadofthebulk.SincethecausticityofLakeOntariowaterisnotastrongfunctionofconcentration,thisdoesnotposeaproblem.'ndeeditisexpectedinthiscasethatafterashortperiodofsteaming,thecrevicechemistrywillbelessbasicthanthatofthebulk.CoolinWaterComositionTheNWTchemistrymodelingworkdiscussedhereinisbasedonthechemicalcompositionofLakeOntariowatersummarizedinTable1assuppliedbyRGE.

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Itispossiblethatseasonalchangesin-thecharacteristics'fthelakewatermay,resultfromtheinterrelationbetweensourceriverflowrates,industrialpollutionand/oracidrain.NWThasnorelevantdatatoassesssucheffects.ItmaybedesirablethatanalysesmadeofLakeOntariowaterduringdifferentseasonsandundervariousconditionsbefedintotheNWTchemistrymodel.InthismannerthesafetyoffeedingLakeOntariowater,overtherangeoflikelychemicalcompositions,canbeverified.

POTENTIALFORSCCA.CorrosionThemostaggressivesolutionexpectedbasedonthemodelingworkis300ppmNaOH,withsl0ppm02(seebelow)at350'F.Althoughlaboratorydataregardingtheseexactconditionsarenotavailable,dataareavailablewhichcanbeextrapolatedtoassessthemaximumcorrosionratesexpectedforagivenrangeofconditions.vanRooyenandKendig'iteWestinghousedataindicatingthatU-bendsofAlloy600indeaeratedlOXNaOHcrackafterseveralmonthsofexposure.Figures2and3summarizeWestinghousetests'hichshowthatatleast100daysofexposuretodeaerated10%NaOHat600'FisrequiredtoproduceadetectablecrackinstressedAlloy600.Figure4showsdatagatheredbyBergeandDonati.~ThesecurvesareforyieldstressedCringsat660'F.ExtrapolatingthecurveformillannealedAlloy600to300ppmNaOHyieldsaminimumtimeof3500-4000hourstoinducea0.5millimetercrack.ThedatapresentedabovearefordeaeratedsystemsandareconsistentwithvanRooyen'sconclusionthatAlloy600in105NaOHwouldnotcrackforseveralmonths.Inthepresenceofoxygen,thesusceptibilityofAlloy600toSCCmaybeincreased.Figure5showsstresscorrosionbehaviorin600'FhighpuritywatercontainingvaryingamountsofoxygeninthegasphaseabovethewaterandadjustedtopH10atstartupwithammonia.Astheoxygencontentofthegasphaseincreased,thepercentofthespecimensattackedandextentoftheattackincreased.AsnotedinFigure5theaveragelifeinthe18-weektestvariedfromnocrackingwith1Xoxygeninthegasphase(<2ppmoxygeninthewater)to7weekswith100Ãoxygeninthegasphase(<200ppmoxygeninthewater).<<IlreeandHichelsandlaterSedriks,etal.,"reportedlessthan20Kcrackingafter27daysforAlloy600(2commonheattreatments)inaerated,50/.NaOHat570'F.

~~(~Cresswatsg.C00eaStressIsss(s/es0ZT5/al50//50tla/IOV0/V.4NtttAhneetdThere((alt/Treats(s~ettass4stt~tstaNXIt(e(ees(reTle(~IhestFigure2.CrackDepthasaFunctionofTime,StressLevelandMaterialConditionforIDPressurizedCapsulesExposedtoDeaerated10$NaOHat600'F,O.e0.3ss5040.3~J0.2Heat5CM.A.T.T.ROT.0118901.OV~SSM.03t~T3Q.04$105HaOH310'CCwlrs051-U05yte505MIHAntsealtd.0768'01ea0.1e~~~I&t000DlssstsreTits(e1hrslTherthallyTreatedFigure3.CrackDepthasaFunctionofExposureTimeforMillAnnealedandThermallyTreatedInconelAlloy600ExposedtoDeaerated10KNaOHat600'F'

,4000CRingsStressedtoa=YsAccordingtoASTMSTP425~o3000SS0Va)IE~rlAo2000Er0)IIK01000Alloy600HT16h1300FAl1oy600MA01,000,10,000'00,000NaOHConcentration,ppmFigure4.ResistancetoStressCorrosionCrackingofAlloy600Mill-Annealed-orHeatTreatedat1300FasaFunctionofDeaeratedSodiumHydroxideConcentrationat600'F' l

~~t2l2l2XWWI20CIo~IOOOZo80~CPI:60W~cL>40.OÃQWW~~2Oill2NO.OFSPECIMENS,MILLANN.8PERCENTCRACKED0AVUFEIN18WEEKTESTS>8AV,OFMAX.CRACKDEPTHS,MIL0tIOO7525892l5500ie00I80l72I888812161818I12181818I818181818181818181818IR18478256ALLOY600HEATN278542478256478256478256100OXYGENINGASATSTART,(%).NILNIL2IBALANCEOFGAS,HYDROGENARGON'ITROGENNITROGENAIR10Figure5.StressCorrosionBehaviorinCreviceAreasinHillAnnealedInconel600DoubleU-bendSpecimensin600'FHighPurityWaterAdjustedtopH10withAmmoniaatStartup' e1 LaboratorystudiesshowthatthereisasignificanttemperaturedependenceofcausticstresscorrosioncrackingasillustratedinFigures6and7.Theseresultsare.forpressurizedcapsulesexposedto10Kand50%NaOHatvaryingstressesattemperaturesrangingfrom650to550'F.Ascanbeseen,reducingthetemperaturebelow,600'F.significantlyextendsthetimeforSCCtooccur.ThistemperaturedependenceisfurtherillustratedinFigure8wheretemperatureisplottedversusrateconstantforboth105and505NaOH.8.OxygenThelakewaterfedtothegeneratorsprobablywouldbeairsaturated(approximately10ppm02).However,at350'FtheKp(theequilibriumratiobetweensteamphaseandliquidphase)foroxygenisslightlygreaterthan5000.Eventhoughthedynamicdistributioninpracticemaynotreachtrueequilibriumconditions,theneteffectofthehighKDvalueisthatrecriculatedsteamgeneratorcoolantwillcontainoxygenconcentrationslowerthan10ppm.Thisrecirculatedcoolantwilldilutetheoxygenconcentrationofincomingfeedwaterwithanetoxygenlevelinthedowncomerof~1to10ppm,dependingontherecirculationratiounderthecontingencyconditions.C.ConclusionWiththesignificantlylowerconcentrationsofsodiumhydroxide(max300ppm),oxygenconcentration<10ppmandthelowertemperature(350'F)involved,thecontingencyoffeedingLakeOntariowatertotheGinnasteamgeneratorsshouIdresultinnomeasureabledamagetosteamgeneratorinternals.A'jthoughnotrecommendedfromthestandpointofmaximizingcomponentlife,suchoperatio~forperiodsuptoseveraldaysisnotexpectedtoresu1tinanysignificantcrackingorinadeteriorationofsteamgeneratorintegrity.

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NaOH50%10%575FII0.5to5mils5030A0)NQlL)flJ>10mils5to10mils100.5to5mils001000200030004000500060007000ExposureTime,hrsFigure6.CausticCrackingofMillAnnealedAlloy600at575'F(Linesdepictzonesofcrackdepthfrom105NaOHat600'F)12 NaOH50%10%550F70<0.5milsCl05to5milsg0.5to5mils50%NaOH650'F5040~~30A~I072010mils5to10mils100.5to5mils00100020003000400050006000ExposureTime,hrsFigure7.CausticCrackingofMi11AnnealedA11oy600at5and650'F)Linesdepictzonesofcrackdepth<<omNaOHat600'F)13 g's"a'll 200MAI-600150IVIJlQCa%40f5IO4JNc5D100500530550570590610630Temperature,FFigUre8.IndicatedVariationinRateofSCCwithTemperat14

'a."S~~PP<~p~~"':~".COMMENTSONVANROOyENANPKE!i01GSREPORT'hereferencedrepo'resbasica)]yi5abroadsummarycoveringalargevolumeofdataapplicableinparttostainlesssteelsandinparttoAlloy600.We~'gg"4"~aregenerallyinagreementwithheirninesummaryconclusions,butfindit"~is@'"8,>>'ifficulttoapply'theirbroad-brushtreatmenttothespecificsofaPWRhot~4'~gp-,'--shutdownwithlake'water'ddedtothesteamgenerators5t350'F.Theirdocumentismisleadingfors'uchanapplicationintworespects:'wC>"..;~0',$4tfkkcf1.CausticConcentrationTheirstatementthat..."ForthenurposesofSCCpredictions,ithastobeassumedthatthetimetoformdangerouslevelsofNaOH,onceimpuritieshavebeenintroduced,isshort,i.e.,onedayorless"doesnotfully,(,--s:irecognizethespecificconcentrationchemistryofthecoolingwaterinvolvednorthelowheatfluxavailableandthecutbackinsteamingrate\'uringaperiodofhotshutdown.!nthecaseoftheLakeOntariowater,forexample,themaximumNaOHconcentrationreachedis300ppm(aftersteaming~20steamgeneratorvo>umes)withadecreaseinconcentrationthereafter.I,raS',~tl2.TemperatureAllofthetestworkreferencedinthereferencedreportswasperformedinthetemperaturerangeof550to630'F.WiththesignificanttemperaturedependenceofcausticSCCasshownabove,theconcernat350Fismanytireslessthanisindicatedfromthedataquotedbytheauthors.'asedontheabovethreeconsiderations.itisourassessmentthatthegeneralizedtimelimitof36ho~rsin:hereport~isnotdirectlyapplicabletotheGinnasteamgeneratorssteam'ng"350'FwhilefedbyLakeOntariowater.15

~1~V1~v

.REFERENCES1.Harhay,A.,.1981.2.3.RochesterGas8Electric,PersonalCommunication,Februaryll,rLeibovitz,J.,andSawochka,S.G.,"ModelingtheEffectsofCondenserInleakageonPWRChemistry",presentedat41stAnnualInternationalWaterConference,Pittsburgh,Pennsylvania,October1980.Leibovi;tz,J.andSawochka,S.G.,"ModelingofCoolingWaterInleakageEffectsinPWRSteamGenerators,TopicalReport,ResearchProject404-1",ElectricPowerResearchInstitute,May1980,tobepublished.4.Mesmer,R.E.,Baes,C.F.,Jr.,andSweeton,F.M.,"BoricAcidEquilibriaandpHinPWRCoolants",Proceedings'ofthe32ndInternationalWaterCon-ference,Pittsburgh,P'ennsylvania,November1971,pp.55-65.vanRooyen,D.,andKendig,M.W.,"ImpureWaterinSteamGeneratorsandIsolationGenerators",BrookhavenNationalLaboratory,June1980(Draft-BNL-NUREG-2814?).6.Airey,G.P.,"EffectofProcessingVariablesontheCausticStressCorrosionResistanceofInconelAlloy600",presentedatNACEMeetingiMarch1979(PaperNumber101).7.8.Berge,Ph.andDonati,J.R.,"MaterialsRequirementsforSteamGeneratorTubing",presentedatInternationalConferenceonMaterialsPerformanceinNuclearSteamGenerators,St.Petersburg,Florida,October1980.Copson,H.R.andEconomy,G.,"EffectofSomeEnvironmentalConditionsonStressCorrosionBehaviorofNi-Cr-FeAlloysinPressurizedWate~".Corrosion,24,No.3,pp.55-65(March1968).9.McIlree,A.R.andMichels,H.T.,"StressCorrosionBehaviorofFe-<<->>andOtherAlloysinHighTemperatureCausticSolutions",Corrosion.33.No.2,pp.60-67(February1977).10.Sedriks,A.J.,etal.,"InconelAlloy690-ANewCorrosionResistantMaterial",-CorrosionEngineering(Japan),28,No.2,pp.82-95(1979).Burstein,S.,WEPCO,ltrtoH.R.Denton,NRC,dtdNovember23withattachments.16

'0st<Vj~f,'JI,r4 HWT167February1981USEOFLAKEONTARIOWATERIHSTEANGENERATORSOURIHGHOTSHUTDOWNW.L.PearlS.E.CopleyJ.LeibovitzPreparedFor'ochesterGas&ElectricCompanyCo%oration7015REALMORIVE,SANJOSE,CALIFORNIA95119 ThisdocumentwaspreparedfortheRochesterGas&ElectricCompany.Neitherthe%/TCorporationnoranypersonactingonitsbehalfassumesanyresponsibilityforliabilityordamagewhichmayresultfromtheuseofanyinformationdisclosedinthisdocument.

INTRODUCTIONThepossibilityofusingLakeOntariowaterasanemergencyPWRfeedwatersupplyformorethan36hoursduringwhichtheplantwouldbebroughttocoldshutdownisbeingconsidered.Themaximumsteamingrateduringsuchaperiodwouldbe100,000pounds/h(200gpm)atatemperatureof350'F.Asaconsequenceofsteaming,impuritiesoftheuntreatedLakeOntariowaterwillconcentrateinthesteamgenerator.Ofmajorconcernisthepossibleriskofstresscorrosioncracking(SCC)ofsteamgeneratormaterialsincontactwiththeconcentratedsolutionthusformed.Toaddressthisconcern,thechemistryvariationintheliquidphaseassteamingproceedsat350'FwasestimatedwithemphasisonpH.Then,thepossiblepotentialforSCCwasassessedonthebasisoftheseestimatesandavailableSCCdata.

6.Theconcentrationofsodiumandcalciumchloridesisassumedlimitedbyasolubilityof5molal.7.Chemicalequilibriumexpressionsofreferences2and3apply.Onthisbasis,theliquidsolutionpHvariationuponsteamingat350'Fwasestimatedasafunctionofconcentrationfactordefinedasthemassratiooftotalwater(steam+liquid)toliquidwaterresidual.TheresultsarepresentedgraphicallyinFigurel.ItisimportanttonotethatthedefinitionofpHusedhereisthatfollowedbyMesmer"inthedeterminationofthedissociationconstantofwaterathightemperatures,viz,thenegativeofthelogarithmofthehydrogenionconcentration(notofitsactivity).Similarly,neutralpHisdefinedasthatwherethehydrogenandhydroxylionconcentrationsareequal.ThisneutralpHisafunctionofionicstrength.Therefore,thepHvariationoftheconcentratedsolutionsmustbeconsideredinrelationtothatofneut.alpH,alsoplottedinFigure1.Forbasicsolutionsasisthecaseconsiderednere,itisimportanttobearinmindthatthehydroxylionconcentrationisexpressedintermsopHasfollows:10pH-2NpHOH(whereNpHistheneutralpHvalue)andthatwhentheneutralpHvariestogetherwiththeionicstrengthastheliquidsolutionisbeingconcentrateduponsteaming,thebasicityofthesolutionmaynotbeappreciatedfromthesolutionpHaloneTheequivalentNaOHconcentrationis.moresuitableforthispurposeandisplottedalsoinFigure1'.B.DiscussionSteamGeneratorBulkWaterBased.onamaximumf'eedrateof'00gpmtothesteamgeneratorandatotals.earngeneratorliquidvolumeof.approximately12,000gallons,amaximumofonesteamgeneratorvolumeissteamedawayeachhour.Therefore,undermaximumsteaming<<nditions,theconcentrationfactorachieved.inthebulksteam.generatorwater.,ist+1~he~etisthenumberofhoursofsteaming.

ThevariationwithtimeoftheequivalentsodiumhydroxideconcentrationinthesteamgeneratorwithsteamingofemergencyLakeOntariofeedwaterthencanbefollowedonFigure1.ItisseenthatamaximumequivalentNaOHconcentrationofabout300ppmwillbereachedinthesteamgeneratorbulkwaterwhen15to20steamgeneratorvolumeswillhavebeenconvertedtosteam,i.e.,inapproximatelytwentyhours.FurtherboilingshouldthendecreasetheequivalentNaOHconcen-trationasmagnesiumand/orcalciumhydroxidesand/orcalciumsulfateprecipitatewithincreasedconcentrating.-Thedecreasereachesalimit(atabout20,000steamgeneratorvolumesconvertedtosteam,i.e.,in20,000hours)whensodiumandcalciumchloridesstarttoprecipitatealso.Thislimitisestimatedatabout100ppmequivalentNaOHforLakeOntariowatercompositionasspecifiedinTableIandwiththeassumptionsalreadystated.Theassumptionsseemreasonableand,atanyrate,canbetestedexperimentallywithasmallautoclavefromwhichknownamountsofLakeOntariowaterwouldbeboiledawayat350'Fatconstantliquidlevelintheautoclave.Crev',cesTheesimatedequivalentNaOHsolutionconcentrationinsteamgeneratorcreviceswi11dependupontherelativedegreeofcrevicesolutionconcentrationabovethebulkwater.Intubetotubesupportplatecrevices,theremaybeadistributionofrelativeconcentrationfactorsofunityandhigher.Thechemistryinacrevicewouldleadthatofthebulkinthesensethatthechemistryofaspecificcrevicewouldtravelthesamecurve(FigureI)asthebulkbutwouIdbe:at.a-pointonthe;curve.somewhataheadof'hebulk.Since'EthecausticityofLakeOntariowaterisnota.strongfunctionofconcentration,thisdoesnotposeaproblem.Indeeditisexpectedinthiscasethatafterashortperiodofsteaming,thecrevicechemistrywillbelessbasicthanthatofthebulk.CoolinMaterComaositionTheNWTchemistrymodelingworkdiscussedhereinisbasedonthechemicalcompositionofLakeOntariowatersummarized.inTableIassuppliedbyRGE.

POTENTIALFORSCCA.CorrosionThemostaggressivesolutionexpectedbasedonthemodelingworkis300ppmNaOH,withs'10ppm02(seebelow)at350'F.Althoughlaboratorydataregardingtheseexactconditionsarenotavailable,dataareavailablewhichcanbeextrapolatedtoassessthemaximumcorrosionratesexpectedforagivenrangeofconditions.vanRooyenandKendig'iteWestinghousedataindicatingthatU-bendsofAlloy600indeaerated10~NaOHcrackafterseveralmonthsofexposure.Figures2and3summarizeMestinghousetests'hichshowthatatleast100daysofexposuretodeaerated10~NaOHat600'FisrequiredtoproduceadetectablecrackinstressedAlloy600.;igure4showsdatagatheredby8ergeandDonati.'hesecurvesareforyieldstressedCringsat660'F.ExtrapolatingthecurveformillannealedAlloy600to300ppmNaOHyieldsaminimumtimeof3500-4000hourstoinducea0.5millimetercrack.ThedatapresentedabovearefordeaeratedsystemsandareconsistentwithvanRooyen's'onclusionthatAlloy600in10%NaOHwouldnotcrackforseveralmonths.Inthepresenceofoxygen,thesusceptibilityofAlloy600toSCCmaybeincreased.Figure5showsstresscorrosionbehaviorin600'Fhighpuritywatercontainingvarying-amountsof'.oxygeninthe-gasphaseabovethewaterandadjustedtopH10'tstartupwithammonia.'stheoxygencontentofthegasphaseincreased,thepercentofthespecimensattackedandextentoftheattackincreased.AsnotedinFigure5theaveragelifeinthe18-weektestvariedfromnocrackingwith1~oxygeninthegasphase(<2ppmoxygeninthewater)to7weeks,with100~oxygeninthegasphase(<200ppmoxygeninthewater).~cIlreeandNichelsandlaterSedriks,etal.,'eportedlessthan20~~~~ckingafter27daysforAlloy600(2commonheattreatments)inaerated,50KNaOHat570F.7 40QOCRingsStressedtocr=YsAccordingtoASTMSTP4253000O4PCJ~~WQ>0001000A11oy600HT16h13QO'FA11oy600MA1,00010.,000100,000NaOHConcentration,ppmFigure4.ResistancetoStressCorrosionCrackingofA11oy60QMi11-Annea1edorHeatTreatedat1300'FasaFunctionofOeaeratedSodiumHydroxideConcentrationat600'F~9

~~LaboratorystudiesshowthatthereisasignificanttemperaturedependenceofcausticstresscorrosioncrackingasillustratedinFigures6and7.Theseresultsareforpressurizedcapsulesexposedto10>>and50Ž~NaOHat,varyingstressesattemperaturesrangingfrom650to550'F.Ascanbeseen,reducingthetemperaturebelow600'FsignificantlyextendsthetimeforSCCtooccur.ThistemperaturedependenceisfurtherillustratedinFigure8wheretemperatureisplottedversusrateconstantforboth10%and50~HaOH.B.OxygenThelakewaterfedtothegeneratorsprobablywouldbeairsaturated(approximately.'0ppm02).However-,at350'FtheK0(theequilibriumratiobetweensteamphaseandliquidphase)foroxygenisslightlygreaterthan5000.EventhoughthedynamicdistribUtioninpracticemaynotreachtrueequilibriumconditions,theneteffectofthehighK0valueisthatrecriculatedstamgeneratorcoolant~~illcontainoxygenconcentrationslowerthan10ppm.Thisrecirculatedcoolan='~>>l'ilutetheoxygenconcentrationofincomingfeedwaterwithanetoxygen:evelinthedowncomerof~lto10ppm,dependingontherecirculationratiounderthecontingencyconditions.CDConclusionthesignificantlylowerconcentrationsofsodiumhydroxide(max300ppm),oxygenconcentrations10ppmandthelowertemperature(350'F)involved,thecontingencyoffeedingLakeOntariowater.totheGinnasteamgeneratorsshould.resultinnomeasureabledamagetosteam-generatorinternaTs.Although:not'ecommendedfromthestandpointofmaximizingcomponentlife,suchoperationforperiodsuptoseveraldaysisnotexpectedtoresu1tinanysignificantcrackingorinadeteriorationofsteamgeneratorintegrity.11

50ZNaOH10X550'PQ<0.5mils0.5to5milsg0.5to5mils50XNaOH650'F5040NII3010mils05ro10mils100.5to5mils0010002000300Q40QO5000ExposureTime,hrs550'FFigure7'.CausticCrackingofMillAnnealed-Alloy600at55and650'F(Linesdepictzonesofcrackdepth<<omNaOHat600'F)13

~,smA~'4%44+AvwCOMMENTSONYAHROUENANPyE!;g..-".'5."-.EPORT,;v~p+W<.-:"'-Thereferencedreportsbas<ca]]v:-...broadsummarycoveringalargevolumeofdataapplicable')npartto...z::.i.sssteelsandinparttoAlloy600.Mearegenerallyinagreementwi:h:".eirninesummaryconclusions,butfindit;~I,&gdifficulttoapply'the)rbroad-br's~treatmenttothespecificsofaPMRhotshutdownwithlakewateradded:o'.'.".=searngeneratorsat350'F.Theirdocument,Ifgm'$ismisleadingforsuchanapplicatonintworespects:tt<<.~~I1.CausticConcentrationTheirstatementthat..."For..-.-;rposesofSCCpredictions,ithastobeassumedthatthetimetoc;"..:vgerouslevelsofNaOH,onceimpuritieshavebeenintroduced,isshor..:.=.,onedayorless"doesnotfullyrecognizethespecificconce"'.r'=.:;;chemistryofthecoolingwaterinvolvednorthelowheat.'!x;:;a;'ableandthecutbackins.earningra.eduringaperiodofhotshu.co<<.'::-.hecaseof.heLakeOntariowater,=orexample,themaxiaam.'4C:":;r':,",-rationreacheds300ppm(afterszeam',ng~20s.earngenera:or.:..-'.;"'.thadecreaseinconcentrationthereafter.2.TemperatureAllofthetestworkreferenced'"";hereferencedreportwasperformedinficanttempeldependenceofcausticSCCasshown.above,theconcernat350'Fismanyti"eslessthanisindicated.from<~<<'aquoted'ytheauthors.Basedontheabovethreeconside<<-ions.itisourassessment,thatthegeneralizedtimelimitof36ho""s'"=ereport'snotdirectlyapp>>ctotheGinnasteamgeneratorsstea"'n"="':350'FwhilefedbyLakeOntariowater.15

~p,RRangy(40Cy/y+w*w~'ocket,'No.50%44LS05-81-04-035UNITEOSTATESNUCL'EARREGULATORYCOMMISSIONWASHINGTON,O.C.20555April24,1981/c&~Mr.JohnE,MaierVice,PresidentElectricandSteamProductionRochesterGas&ElectricCorporation89EastAvenueRochester,NewYork14649

DearMr.Maier;SUBJECT:

SEPTOPICSV-ll.A,ISOLATIONOFHIGHANDLOWPRESSURESYSTEMS,V-ll,B,RHRINTERLOCKREQUIREMENTSANDVI-7.C.l,INDEPENDENCEOFREDUNDANTQ5SITEPOWERSYSTEMS-.R,E,GINNANUCLEARPOWERPLANTWehavereviewedyourletterofMarch27,1981andagreewithresolvingopenitemsduringtopicevaluationsratherthandeferringadecisiontotheIntegratedAssessment,Tothisend,weareenclosingarevisedsafetyevaluationofTopicV-ll.A.WehavealsoreviewedyourcommentsonthedraftTechnicalEvaluationReport(TER)SEPTopicV-ll.BdatedJanuary8,1981,Yourcommentson'EPTopicV-'1.BarecoveredbySections3.1and3.2ofoursafetyevalua-tiononSEPTopicV-ll,A.WeareenclosingarevisedTechnicalEvaluationReportonTopicV-ll.BwhichincorporatesareferencetoSection3,1and3.2ofoursafetyevaluationreportonTopicV-ll.A.WeareenclosingarequestforadditionalinformationonSEPTopicVI-7,C,lwherewedonothavesufficientinformationtoreachanindependentsafetyassessment.Sincerely,'

Enclosure:

WaSERforSEPTopicV-ll.Aguestjonsf'rSEPTopicVI-.7.C,1ccw/enclosure'eenextpageDennisM,Crutchfield,iefOperatingReactorsBranchNo,5DivisionofLicensing

SAFETYEVALUATIONTOPIC:V-ll.ARequirementsforIsolationofHighandLowPressureSystemsSeveralsystemsthathavearelativelylowdesignpressureareconnectedtothereactorcoolantpressureboundary',Thevalvesthatformtheinterfacebetweenthehighandlowpressuresystemsmusthavesufficientredundancyandinterlockstoassurethatthelowpressuresystemsarenotsubjectedtocoolantpressuresthatexceeddesignlimits.Theproblemiscomplicatedsinceundercertainoperatingmodes(e.g,,shutdowncoolingandECCSinjection)thesevalvesmustopentoassureadequatereactorsafety,AsnotedinEG&GReport1285(AppendixA),GinnahasthreesystemswithalowerdesignpressureratingthantheRCS,thataredirectlyconnectedtotheRCS.TheRHR,SIS,andCVCSsystemdonotmeetcurrentlicensingrequirementsforisolationofhighandlowpressuresystemsasspecifiedbelow.(1)TheRHRsystemisnotincompliancewiththecurrentlicensingrequire-mentsofBTPRSB5-1sincenoneoftheisolationvalveswillautomaticallycloseifRCSpressureexceedsRHRdesignpressure.Also,theoutboardisolationvalveshavenointerlockstopreventRHRoverpressurization,andtheinboardvalveinterlocksareneitherdiversenorindependent,(2)TheSISisnotincompliancewiththecurrentlicensingrequirementsofSRP6.3sincetheMOVsinthelowpressureinjectionlineshavenointerlockstopreventopeningwheretheRCSpressureandthesinglecheckv'alveineachlineisnottested.(3)TheCVCSisnotincompliancewithcurrentlicensingrequirementsforisolationofhighandlowpressuresystemscontainedinBTPEICSB-3sincethesuctionanddischargelinesolenoid-operatedvalveshavenointerlockstopreventsystemoverpressurization,andthedischargelinecheckvalveshavenopositionindicationavailableinthecontrolroom.BecauseofthesevereconsequencesofaLOCAoutsideofcontainmentandthelackofassurancethattheseisolationvalvescouldbeclosedagainstsignifi-cantflowundertheresultingenvironmentalconditions,theRHRisolationvalvesandtheCVCSsuctionvalvesshouldbemodifiedtosatisfythefunctionalrequire-mentsofBTPRSB5-1andBTPEICSB-3.Themodificationsofthisequipmentshouldmeetcurrentcriteriaforseismicandenvironmentalqualification.Thescheduleforinstallingthesemodificationswillbedeterminedduringtheintegratedassessmentportionofourreview.ThebasisforrequiringdiverseinterlocksintheRHRoutboardisolationvalvesisthat,ifanoperatoropenstheoutboardvalveandtheinboardvalveleaks,anuncontrolledLOCAoutsideofcontainment(EventV)couldpossiblyoccur. ..Thebasisfornotrequiringinterlocksin.thelowpressureinjectionsystemisthat,sincethecontractor'sreportwaspublished,acheckvalvetestprogramhasbeenestablished,andthus,thesystemnowsatisfiesthesingle.failurecriterion.ThebasisforrequiringtheinterlocksonthesuctionandpositionindicationonthedischargecheckvalvesintheCVCSsystemisthatafailureofthereliefvalvetofunctionwhenrequired.may'eadtooverpressurizationandasubsequenteventV.ThebasisfornotrequiringinterlocksontheCVCSdischargevalvesisthatthecheckvalvesinserieswiththepositivedisplacementpumpssatisfythesinglefailurecriterionaslongascheckvalvepositionisknownandthepumpcapacityisverifiedperiodically.Aspreviouslynoted,inoursystemssafetyevaluationofSEPTopicV-lO.B,itisnotnecessarytoclose-theRHRvalvesautomaticallyonincreasingreactorcoolantsystempressureduringstartupbecauseoftheoverpressurizationpro~tectionsystem.(SeealsoTopicV-3.)

.hcGIj(C~CeW+s*e+DocketNo.50-244LS05-81-02-060UNITEDSTATESNUCLEARREGULATORYCOMMISSIONWASHINGTON,D.C.20555r~r"G21ala~iMr.JohnE.MaierVicePresident.ElectricandSteamProductionRochesterGas8ElectricCorporation89EastAvenueRochester,NewYork14649

DearMr.Maier:

RE:SEPTOPICSV-II.A,ISOLATIONOFHIGHANDLOWPRESSURESYSTEMS,ANDVI-7.C.1,INDEPENDENCEOFREDUNDANTONSITEPOWERSYSTEMS-R.E.GINNANUCLEARPOWERPLANTEnclosedarefinalevaluationsofSEPTopicsV-II.AandVI-7.C.lforR.E.GinnaNuclearPowerPlant.Theseassessmentscompareyourfacility,asdescribedinDocketNo.50-244,withthecriteriacurrentlyusedbytheregulatorystaffforlicensingnewfacilities.ThesereportshavebeenrevisedtoreflectthefactualcommentsprovidedbyyourJanuary8,1981letter.Yourobservationswithregardtotheacceptabilityofalternativedesignsandtheuseofadministrativecontrolswillbeconsideredduringourpreparationoftheintegratedsafetyassessmentforyourplant.However,itmustbepointedoutthatthecurrentlyapprovedversionofRegulatoryGuide1.139isRevision0.Revision0requiresdiverseinterlocks.Theseevaluationswillbebasicinputstotheintegratedsafetyassess-mentforyourfacility.Aspreviouslystated,theseassessmentsmayberevisedinthefutureifyourfacilitydesignischangedorifNRCcriteriarelatingtothissubjectaremodifiedbeforetheintegratedassessmentiscompleted.Sincerely,,

Enclosure:

DraftSEPTopicsV-II.AandVI-7.C.1ccw/enclosure:SeenextpageDennisM.Crutchfield,iefOperatingReactorsBranch85DivisionofLicensing

.iMr.JohnE.Maierccw/enclosure:HarryH.Voigt,EsquireLeBoeuf,Lamb,LeibyandMacRae1333NewHampshireAvenue,N.M.Suite1100Washington,D.C.20036Mr.MichaelSlade12TrailwoodCircleRochester,NewYork14618RochesterCommitteefor-ScientificInformationRobertE.Lee,Ph.D.P.0.Box5236RiverCampusStationRochester,NewYork14627JeffreyCohenNewYorkStateEnergyOfficeSwanStreetBuildingCore1,SecondFloorEopireStatePlazaAlbany,NewYork'2223Director,TechnicalDevelopmentProgramsStateofNewYorkEnergyOfficeAgencyBuilding2EsquireStatePlazaAlbany,NewYork12223RochesterPublicLibrary115SouthAvenueRochester,NewYork14604SupervisoroftheTownofOntario107RidgeRoadMestOntario,NewYork14519ResidentInspectorR.E.GinnaPlant.c/oU.S.NRC1503LakeRoadOntario,NewYork14519RichardE.Schaffstall,ExecutiveDirectorforSEPOwnersGroup1747PennsylvaniaAvenue,NWWashington,D.C.20006R.E.GINNANUCLEARPOWERPLANTDOCKETNO.50-244Director,TechnicalAssessmentDivisionOfficeofRadiationPrograms(AW-459)U.S.EnvironmentalProtectionAgencyCrystalHalIf2Arlington,Virginia20460U.S-EnvironmentalProtectionAgencyRegionIIOfficeATTN:EISCOORDINATOR26FederalPlazaNewYork,NewYork10007HerbertGrossman,Esq.,ChairmanAtomicSafetyandLicensingBoardU.S.NuclearRegulatoryComnissionWashington,D.C.20555Dr.RichardF.ColeAtomicSafetyandLicensingBoardU.S.NuclearRegulatoryComissionMashington,D.C.20555Dr.EmnethA.LuebkeAtomicSafetyandLicensingBoardU-S.NuclearRegulatoryComnissionMashington,D.C.20555Hr.ThomasB.Cochran~NaturalResourcesDefenseCouncil,Inc.1725IStreet,N.M.Suite600Washington,.D.C.20006EzraI.BialikAssistantAttorneyGeneralEnvironmentalProtectionBureauNewYorkStateDepartmentofLaw2WorldTradeCenterNewYork,NewYork10047 0130JSEPTECHNICALEVALUATIONTOPICV-11.AELECTRICAl,INSTRUMENTATION,ANDCONTROLFEATURESFORISOLATIONOFHIGHAi%)LOWPRESSURESYSTEMSFINALDRAFTR.E.GINNANUCLEARSTATIONDocketNo.50-244January1981S.E.Mays1-26-81 CONTENTS

1.0INTRODUCTION

2~0CRITERIA~~~~o~~~~~~~~~~~2.1ResidualHeatRemoval(RHR)System.2.2EmergencyCoreCoolingSystem2.3OtherSystems1~2~23.0DISCUSSIONANDEVALUATION~~~~~~~~~~33.1ResidualHeatRemoval(RHR)System.3.2SafetyInjectionSystem3.3ChemicalandVolumeControlSystem.~~~~~"~~~~~~3344o0SUMMARY~~~~~~~~~~~~~~~~~~~~~~~~5>F0REFERENCES~~~~~~~~~~o~~~~~~~~~~~~~~~6 SEPTECHNICALEVALUATIONTOPICV-ll.AELECTRICAL,INSTRUMENTATION,ANDCONTROLFEATURESFORISOLATIONOFHIGHANDLOWPRESSURESYSTEMSFINALDRAFTR.E.GINNANUCLEARSTATION

1.0INTRODUCTION

Thepurposeofthisreviewistodetermineiftheelectrical,instrumentation,andcontrol(EI&C)featuresusedtoisolatesystemswithalowerpressureratingthanthereactorcoolantprimarysystemareincompliancewithcurrentlicensingrequirementsasoutlinedinSEPTopicV-llA.Cuzrentguidanceforisolationofhighandlowpres-suresystemsiscontainedinBxanchTechnicalPosition(BTP)EICSB-3,BTPRSB-5-1,andtheStandardReviewPlant(SRP),Section6.3.2.0CRITERIA2.1ResidualHeatRemoval(RHR)Sstems.'solationrequirementsforRHRsystemscontainedinBTPRSB"5-1axe:1.Thesuctionsidemustbeprovidedwiththefollowingisolationfeatures:a.Twopower-operatedvalvesinserieswithposi-tionindicatedinthecontrolroom.b.Thevalvesmusthaveindependentanddiverseinterlockstopreventopeningif'hereactorcoolantsystem-(RCS)pressuxeisabovethedesignpressureoftheRHRsystem.C~ThevalvesmusthaveindependentanddiverseinterlockstoensureatleastonevalveclosesuponanincreaseinRCSpressureabovethedesignpressureoftheRHRsystem.2.Thedischargesidemustbeprovidedwithoneofthefollowingfeatures:a.Thevalves,positionindicators,andinterlocksdesczioedin(1)(a)'hxough(1)(c)above.

boOneormorecheckvalvesinserieswithanormally-closedpower-operatedvalvewhicnhasitspositionindicatedinthecontrolroom.IfthisvalveisusedforanEmergencyCoreCoolingSystem(ECCS)function,thevalvemustopenuponreceiptofasafetyinjectionsignal(SIS)whenRCSpressurehasdecreasedbelowRHRsystemdesignpressure.c.Threecheckvalvesinseries.d.Twocheckvalvesinseries,providedthatbothmaybeperiodicallycheckedforleaktightness----andarecheckedatleastannually.2.2EmerencCoreCoolinSstem.IsolationrequirementsforECCSarecontainedinSRP6.3.Isola'tionofECCStopreventoverpres-surizationmustmeetoneofthefollowingfeatures:l.Oneormorecheckvalvesinserieswithanormally<<closedmotor>>operatedvalve(MOV)whichistobeopeneduponreceiptofaSISwhenRCSpressureislessthantheECCSdesignpressure2.Threecheckvalvesinseries3..Twocheckvalvesinseries,providedthatbothmaybeperiodicallycheckedforleaktightnessandarecheckedatleastannually.J*withtheRCSmustmeettnefollowingisolationrequirementsfromBTPEICSB-3:AtleasttwovalvesinseriesmustbeprovidedtoisolatethesystemwhenRCSpressureisabovethesystemdesignpressureandvalvepositionshouldbeprovidedinthecontrolroom2.ForsystemswithtwoNOVs,eachNOVshouldhaveindependentanddiverseinterlockstopreventopeninguntilRCSpressureisbelowthesystemdesignpressureandshouldautomaticallyclosewhenRCSpressureincreasesabovesystemdesignpressure3.ForsystemswitnonecheckvalveandaMOV,theMOVshouldoeinterlockedtopreventopeningifRCS pressureisabovesystemdesignpressureandshouldautomaticallyclosewheneverRCSpressureexceedssystemdesignpressure.3.0DISCUSSIONANDEVALUATIONTherearethreesystemsatR.E.GinnaNuclearStationwhichhaveadirectinterfacewiththeRCSpressureboundaryandhaveadesignpressureratingofallorpartofthesystemwhichislessthanthatoftheRCS.ThesesystemsaretheChemicalandVolumeControlSystem(CVCS),theSafetyInjectionSystem(SIS),andtheResidualHeatRemoval(RHR)systern.3.1ResidualHeatRemovalSstem.TheRHRsystemtakesasuctionontheRCSloopAhotleg,circulatesthewaterthroughtheRHRsystemheatexchanger,anddischargestotheRCSloopBcoldleg.Twomotor-operatedvalvesinseriesprovideisolationcapabilitiesinboththesuctionanddiscnargelines.EachoftheseNOVshaspositionindica-tioninthecontrolroom.Theinboard(closesttotheRCS)valvesareinterlockedtopreventopeningifRCSpressureisaboveRHRsystemdesignpressure.However,bothvalvesusethesamepressureswitchandrelaytoprovidethisinterlock.Theoutboardvalveshavenopressureinterlocks.NoneofthevalveswillautomaticallycloseifRCSpres-suzeincreasesaboveRHRsystemdesignpressureduringRHRsystemoperation.TheRHRsystemisnotincompliancewiththecurrentlicensingrequirementsofBTPRSB-5"1sincenoneoftheisolationvalveswillautomaticallycloseifRCSpressureexceedsRHRdesignpressure.Also,theoutboardisolationvalvesnavenointerlockstopreventRHRoverpressurization,andtheinboardvalveinterlocksareneitherdiversenorindependent.3.2SazetIn'ectionSstem.OneSISsubsystemconsistsoftwoaccumulatorspressurizedwithnitrogenwitheachaccumulatorisolatedrzomtheRCSbyapairofcheckvalves.Thereareconnectionsupstreamozeacncneckvalvethatcanallowthemtobetested.Anormally-open motor-operatedisolationvalveupstreamofthecheckvalvesforeachaccumulatorhaspositionindicationinthecontrolroom.EachMOVisopenedautomatically,i.fclosed,uponreceiptofasafetyinjectionsignal.ThesecondSISsubsystemconsistsoftwoloops,eachsuppliedbyasafetyinjectionpump.EachpumpdischargestothehotandcoldlegsofoneRCSloop.Isolationisprovidedbytwocheckvalvesinseriesforeachbranchofthesafetyinjectionloop.Thecoldlegcheckvalvesaretestable.ThecheckvalvesinthelinessupplyingtheRCShotlegforeachSISlooparenottestable.However,theMOVineachhotlegislockedshutwithpowerremovedandisnotrequiredforaccidentmitigation.Amotor-operatedisolationvalvewithpositionindicationinthecontrolroomisprovidedineachbranchofthecoldleg.dischargelines.Thesevalvesopenuponreceiptofasafetyinjectionsignal,buthavenointerlockspreventingopeningwhenRCSpressureisaboveSISdesignpressure.ThethirdSISsubsystemusestheRHRsystemtoprovidelowpres-surewaterfromtherefuelingwaterstoragetanktothereactorvesselhead(coredeluge).IsolationisprovidedbyaMOVcheckvalveineachoftwobranches.TheMOVsopeninserieswithauponreceiptofasafetyinjectionsignalbuthavenointerlockstopreventopeningwhenRCSpressureisaboveSISdesignpressure.TheSISisnotincompliancewiththecurrentlicensingrequire-mentsofSRP6.3sincetheMOVsforthelowpressureinjectionlineshavenointerlockstopreventopeningwhenRCSpressureexceedsSISdesignpressure.3.3ChemicalandVolumeControlSstem.TheCVCStakeswaterfromtheRCSandpassesitthrougharegenerativeheatexchanger,anorificetoreduceitspressure,andanonregenerativeheatexchangerbeforereducingitspressure'furtherbytheuseofapressurecontrolvalve.Afterfilteri.ngandcleanup,thewatermaybereturnedtotheRCSbytheuseofthecnargingpumps,whichincrease.thewaterpressure

andpassitthrougntheregenerativeheatexchangertoeitnerthehotorcoldlegsoftheRCSortothepressurizerauxiliarysprayline.TheCVCSsuctionlineisolationisprovidedbyamanually-operatedsolenoidvalveinserieswiththreeparallelsolenoid-operatedvalves.Eachofthesevalvesisoperatedfromthecontrolroomandhasvalvepositionindicated.Noneofthevalveshaveinterlockstopreventopeningortoautomaticallycloseifthepressureexceedsthedesignratingofthelowpressureportionsofthesystem.TheCVCSdischargelineisolationisprovidedbyacommondis-chargelinecheckvalveandabranchcheckvalveineachofthethreebranchesdownstream,ofthecommoncheckvalve.Drainfittingsonthedischargelineupstreamofeachcheckvalvecanallowthevalvestobetested.Thereisnopositionindicationavailableinthecontrolroomforthecheckvalves.Therearesolenoidisolationvalvesineachdiscnargelinebranchwhichhavepositionindicationinthecontrolroom,butthesevalveshavenointerlockstopreventsystemoverpressurization.TheCVCSisnotincompliancewithcurrentlicensingrequirementsforisolationofhighandlowpressuresystemscontainedinBTPEZCSB-3sincethesuctionlinesolenoid-operatedvalveshavenointerlockstopreventsystemoverpressurization,andthedischargelinecheckvalveshavenopositionindicationavailableinthecontrolroom.4.0SUaiRYTheR.'.GinnaNuclearStationhasthreesystemswithalowerdesignpressureratin'gthantheRCS,whicharedirectlyconnectedtotheRCS.TheCVCS,SIS,andRHRsystemdonotmeetcurrentlicensingrequirementsforisolationofhighandlowpressuresystemsasspeci-fiedbelow.

~I~~1.TheCVCSsolenoid-operatedvalveshavenopressure-relatedinterlocks,andthedischargelinecheckvalveshavenopositionindicationavailableinthecontrolroomasrequiredbyBTPEICSB-32.TheMOVsinthelowpressureSISlineshavenopressure-relatedinterlocksrequiredbySRP6.33.NoneoftheRHRsystemisolationvalvesautomati-callycloseifRCSpressureincreasesaboveRHRsystemdesignpressureduringRHRsystemoperation,andtheoutboardisolationvalveshavenopressure-relatedinterlocksasrequiredbyBTPRSB-5-1.Theinterlocksfortheinboardisolationvalvesareneitherdiversenorindependent.50REFERENCES1.NUREG-075/087,BranchTechnicalPositionsEICSB-3,RSB-5-1;StandardReviewPlano.3.2.UpdatedFinalFacilityDescriptionandSafetyAnalysisReport,GinnaNuclearPowerPlant,UnitNo.1.3.RG&Edrawings33013-422,-424'257426'27'28'32'33'434,-435,and-436.4.RGGEdrawings10905-280,-285,-287,-295,-296,-300,and-301.

TOPICY-11,8(SYSTH'8)SEETOPICV-'lO.A gy,RRfgyc<~oCy'A+~~O+**++Docket'No.50-244LS05-81-04-035UNITEDSTATESNUCL'EARREGULATORYCOMMISSIONWASHINGTON,D.C.20555April24,1981gj/Mr.John.E.MaterVicePresidentElectricandSteamProductionRochesterGas8ElectricCorporation89EastAvenueRochester,NewYork14649

DearMr.Maier;SUBJECT:

SEPTOPICSV-ll.A,ISOLATIONOFHIGHANDLOWPRESSURESYSTEMS,V-ll,B,RHRINTERLOCKREQUIREMENTSANDVI-7.C.l,INDEPENDENCEOFREDUNDANTVISITEPOWERSYSTEMS-R.E.GINNANUCLEARPOWERPLANTWehavereviewedyourletterofMarch27,1981andagreewithresolvingopenitemsduringtopicevaluationsratherthandeferringadecisiontotheIntegratedAssessment,Tothisend,weareenclosingarevisedsafetyevaluationofTopicV-ll.A.Wehavealsoreviewedyourcomments-onthedraftTechnicalEvaluationReport(TER)SEPTopicV-ll.BdatedJanuary8,1981,YourcommentsonSEPTopicV-ll.BarecoveredbySections3.1and3.2ofoursafetyevalua-tiononSEPTopicV-ll,A.WeareenclosingarevisedTechnicalEvaluationReportonTopicV-ll.BwhichincorporatesareferencetoSection3,1and3.2ofoursafetyevaluationreportonTopicV-ll.A.WeareenclosingarequestforadditionalinformationonSEPTopicVI-7,C,1wherewedonothavesufficientinformationtoreachanindependentsafetyassessment.Sincerely,'nclosure:SERforSEPTopicV-ll.AQuestionsforSEPTopicVI-.7.C.lccw/enclosure:SeenextpageDennisM,Crutchfield,iefOperatingReactorsBranchNo,5DivisionofLicensing

Hr.JohnE.MaierCCHariyH.Voigt,EsquireLeBoeuf,Lamb,LeibyandNacRae1333Ne~(HampshireAvenue,N.W.Suite1100Washington,D.C.20036t<r.MichaelSlade12TrailwoodCircleRochester,NewYork14618EzraBialikAssistantAttorneyGeneralEnvironmentalProtectionBureauNewYorkStateDepartmentofLaw2WorldTradeCenterNewYork,NewYork10047JeffreyCohenNewYorkStateEnergyOfficeSwanStreetBuilding,Core1,SecondFloorEmpireStatePlazaAlbany,NewYork12223Director,TechnicalDevelopmentProgramsStateofNewYorkEnergyOfficeAgencyBuilding2EmpireStatePlazaAlbany,NewYork12223RochesterPublicLibrary115SouthAvenueRochester,NewYork14604SupervisoroftheTownofOntario107RidgeRoadWestOntario,NewYork14519ResidentInspectorR.E.GinnaPlantc/oU.S.NRC1503LakeRoadOntario,NewYork14519Director,CriteriaandStandardsDivisionOfficeofRadiationPrograms(ANR-460}U.S.EnvironmentalProtectionAgencyWashington,D.C.20460U.S.Environmenta1.ProtectionAgencyRegionIIOfficeATTN'ISCOORDINATOR26Federal,PlazaNewYork,NewYork10007HerbertGrossman,Esq.,ChairmanAtomicSafetyandLicensingBoardU.S.NuclearRegulatoryCommissionWashington,D.C.20555Dr.RichardF.ColeAtomicSafetyandLicensingBoardU.S.NuclearRegulatoryComnissionMashington,D.C.20555Dr.EmethA.LuebkeAtomicSafetyandLicensingBoardU.S.NuclearRegulatoryCowrissionMashington,D.C.20555Hr.ThomasB.CochranNaturalResourcesDefenseCouncil,Inc.1725IStreet,N.M.Suite600Washington,D.C.20006EzraI.BialikAssistantAttorneyGeneralEnvironmentalProtectionBureauNewYorkStateDepartmentofLaw2WorldTradeCenterNewYork,NewYork10047 4~<~w-'~-.~mEnergyMeasurementsGroup,EGG1183-415421April1981SYSTFMAT/CEVALUATIONPROGRAMRFVIEVfQFNRCSAFETYTOPICV-II.BASSOCIATEDWITHTHEELECTRICAL,IHSii-UiYiKNTATIQN,Ai~'DCONTROLPQRTIOF~SQFTHERESIDUALHEATRED"<OVAL.SYSTEMFORTHEGINNANUCLEARPQVZERPIARTSANRAMONOPERATIONS29C".GLG<<rCWC~NYC4PC9cN84MCQ,CAglsGANIA9(<99 EGG1183-4]S4SYSTEMATICEVALUATIONPROGRAMREYIDVQFNRCSAFETYTOPICV-31.BASSOCIATEDVflTHTHEELECTRICAL,INSTRUMENTATION'NDCONTROLPORTIONSOFTHERESIDUALHEATREMOVALSYSTEMFORTHEGINNANUCLEARPOWERPLANT ABSTRACTThisreportdocumentsthetechnicalevaluation'ndreviewofNRCsafetytopicY-,li.B,associatedwiththeelec.rical,instrumentation,andcontrolpor.ionsoftheresidualheatremoval(RHR)systemfortheGinnanuclearpowerplant.Currentlicensingcriteriaareusedtoevaluate.theoverpressureprotectionandincependenceoftheRHRsys.em.

FQREMCROThisrepor.issupp1iedaspartoftheSystematicEvaluationProgrambeingconductedfortheU.S.NuclearRegulatoryCommissionbyLawrenceLivermoreNationalLaboratory.Theworkwasperformedby.EGEG,EnergyMeasurementsGroup,SanRamonOperationsforLawrenceLivermoreNationalLaboratoryunderU.S.OepartmentofEnergycontractnumberOE-AC08-75NV01183.

TABLEOFCONTENTSPage1.INTRODUCTION............12.C'URREHTLICEHSIHGCRITERIA~~oe~~~'o~33~REYIFhGUIDE'NES-~-..'~....~54.SYST"-t1DESCRIPTiON...........75.EVALUATIONANDCONCLUSIONS.......~.96.SUM~VRY~~~~llR=".=ERENCES~~~o13'PPENDIXAHRCSAFETYTOPICSRELATEDTOTHiSREPORT...A-1

SYSTEMATICEVALUATIONPROGRAMREVIEMOFNRCSAFETYTOPICV-11.BASSOCIATEDWITHTHEELECTRICAL,INSTRUMENTATION,ANDCONTROLPORTIONS.OFTHERES'IDUALHEATREMOVALSYSTEMFORTHEGINNANUCLEARPOMERPLANT1.INTROOUCTIQNAnumberofplantshaveresidualheatremoval(RHR)sysemsin0whichthedesignpressureratingislowerthanthereactorcoolantsystem(RCS)pressure,boundarytowhichthesystemisconnected.TheRHRsystemnormallyislocatedoutsideofprimarycontainmentandhasmotor-operaedvalves(MOVs),whichisolateitfromtheRCS.Thereis,therefore,apo-tentialthatthesesystemswouldbesub'ctedtopressurestressesinexcessoftheirdesignratingiftheisolationMOVswereopenedinadvert-entlywhiletheRCSwasabovetheRHRsystemdesignpressurerating.ThiscouldresultinaLOCAou-sidecontairmentandalossofrefloodcapabilitysince'hecoolantinventorycould.belost.Generally,interlocksareprovidedtopreventisolationMOVsfrcmopeningunderhighRCSpressureconditions.Itisimportantoincorporatefeaturesintothesystemdesign.whichwillpreventoverpressurizingthelowpressure-ratedRHRsystemswhichinterfacewiththereactorcoolantpressureboundary.Thecurrentlicensingcriteriarequiresredundant,diverseinterlockstopreventopeningoftheisolationMOVswhenRCSpressureexceedsRHRpressuredesign

limits.ThecurrentlicensingcriteriaalsorequiresautomaticclosureoftheisolationNOYswhenRCSexceedsRHRpressuredesignlimits.Theobjectiveofthisreviewistoensurethattheplanthasadequatemeasurestoprotectalowpressure-ratedRHRsystemthatinter-faceswith.heRCSfromfailuresduetoexcessivepressureandthatsuchprotectionissuitablyredundantanddiverse.Thisreviewappliestotheinterlocksassocia.edwiththeisola-tionNOYsoftheRHRsystem.Otherprotectionschemessuchasdouble-testablechekvalvesarediscussed'nreportsonotherNRCSafetyTopics.'

2.CURRENTL'ICENSINGCRiTERIABranchTechnicalPositionICSB-3[Ref.13,entitled"IsolationofLowPressureSystemsfromtheHighPressureRCS,"statesthat:TheisolationMOYsshouldhaveindependentanddiverseinterlockstopreventopeningunlesstheprimarysystempressureisbelowthesubsystemdesignpressure.Also,theisola.ionNOYoperatorsshouldreceiveasignaltoclosethevalvesautomaticallywhentheprimarysysempressureex-ceedsthesubsystemdesignpressure.BranchTechnicalPositionRSBS-IiRef.2j,entitled"OesignRe-qu'.rementsfortheResidual'~eatRemovalSystem,"statesthat:Isolationshal1beprovidedbyat1esttwopower-operatedvalves.inseries,andthevalvessnailhaveindependentdiverseinterlockstopreventthevalvesfrombeingopenedunlesstheRCSpressureisbelowtheRHRsystemdesignpres-sure.Thevalvesshallhaveindependent,diverseinterlockstoprotectagainstoneorbothvalvesbeingopenduringanincreaseaboveRHRsystemdesign'pressure.IftheRHRsystemdischargelineisusedforanemergencycorecoolingsysem(ECCS)function,thepower-operatedvalveistobeopeneduponreceiptofasafetyinjecionsignaloncethereactorcoolantpressurehasdecreasedbelowtheECCSdesignpressure.

3.REVIEWGUIDELINESTheNRCguidelinesusedinthisreviewareasfollows:t(1)IdentifythevalveswhichisolatetheRHRsystemfranthereactorcoolantpressureboundry:(RefertoNRCmemorandumfromB.L.Siegel,RSB,toP.A.OiBenedetto,SEP;whichisenclosure3ofaletterfromCrutchfieldNRC,SEPB,toDittmore,LLNL,dated6'-10-80[Ref.3]).(2)(3)Evaluate(hedesignfeatureswhichprovideprotec-tion=-gainsttheoverpressurizationcftneRHRsystem.Identifytherelatedtopicreviewsinanappendixuthisreport.(4)CompilealistofthemajorEISCsystemsthatarenecessaryforOBEandforsafeshutdownoftheplant.SubmitthecompilationofnecessaryitemsforsafeshutdownasanappendixtoNRCSafetyTopicYII-3,entitled"SystemsRequiredforSafeShutdown."(5)Ifpowerislocked-outtotheRHRisolationMOYs,revie~todetermineifanyfunctionsoftheinter-locksorperm..'ssivesareadverselyaffec.ed.(ThereportonNRCSafetyTopicYi-7.C,amongothers,sta.eswhichvalueshavepowerlockedout).

4.SYSTEMDESCRIPTIONTheRHRloopconsis.softwopumps,twoheatexchanoers,andthenecessaryvalves,piping,andinstrumen;ation.Duringplantcooldown,coolantflowsfrcmtheRCStotheRHRpumps,throughthetubesideoftheRHRheaexchangersandbacktotheRCS.ThesingleinletlinetotheRHRloopcommencesathehotlegofractorcoolantloopA,throughtwore-dundan.pumps.'ndthei,rassociatedheatexchangers,andbacktothecoldlegofreactorcoolantloop8viaasingleheader.rTheRHRpumpsandhea.exchangersservedualfunct',cns.Al:houghthenormaldu".yof.heRHRpumpsandheatexchangersisperformedduringperiodsofreac.orshutdown,thisequipmentisalignedduringtheinjectionphaseafteraloss-of-coolant-accident(LOCA)toperformthelow-headsafetyinjection'(LPSI)function.Inaddition,duringtherecirculetonphaseofaLOCAthecapabilitymaybedividedbetweenthe.core-coolingfunctionandthecortainment-coolingfunctionasapartofthecontainmentspraysystem.

5.EVALUATIONANDCONC'SIONSThesuctionlineoftheRHRsystemisisolatedfromtheloopAhotlegoftheRCSbyMOV-700andMOV-701inseries.ThedischargelineoftheRHRsystemisisolatedfrcmtheloopBcoldlegoftheRCSbyMOV-720andMOV-721inseries.I:Ref.4,drawing33013-436-A].Allpermissiveinterlocksassociatedwi.htheRHRsysemisola-tionMOYsaredesignedtoopenthevalves;therearenopermissiveintr-locksassociatedwithisola.ionMOYclosure.Sec.ion4.1of..theSEPreviewoSafeShudownSyste.,s[Ref;5jstatesthatthepermissiveinterlocksrequiredtoopenthefourRHRsys.emisola.ionvalvesareaslistedbelow:MOV-700....RCSpressuremustbelessthan410psig.RHRsuctionvalvesMOV-850AandMOY-850Bfranthecontainmentsumpmustbeclosed.MOY-701....Thevalve.isoperatedbyakeyswitch.RHRsue.ionvalvesMOV-850AandMOY-8508from.hecontainmentsumpmustbeclosed.MOV-720....Noin;erlocksexist;valveoperatedbykeyswltch~1MOV-721....RCSpressuremustbelessthan410psig.TheRHRsystemdischargelineisnotusedforanECCSfunctionthatwouldrequireMOY-720orMOY-721.oopen;however,abranchof.heRHRdischargelineprovideslowpressuresaetyinjecton(LPSI)tothereac.orvesselviaparal1ellines.isolationbetweenheRHRsystemandLPSinjecioninto.hereactorve'sselisprovidedbytwoseparatepathsfromtheRHRdischargeline,~itheachpathcontaininganMOYandcheckvalve,MOY-852Aandcheckvalve853Aprovideisolationinonepath,whileMOY-852Bandcheckvalve8538provideisolaionintheotherpathI:Ref.4,drawing 33013-436-A;Ref.6,drawing33013-432-A].TheLPSIisolationMOYsopenonaSIsignalregardlessofRCSpressure;.herearenointerlocksassociated~ithclosureofthe'LPS'IisolationMOYs,althoughkeyswi.chclosurecap-abilityisprovided.Section-".1oftheSEPreviewofSafeShutdownSystem[Ref.53statesinpartthat:AbranchoftheRHRdischargelineprovideslowpressuresafetyinjection(LPSI)tothereactorvesselviaparallellineswithonenormallyclosedmoor-operatedvalve(NOV)andonecheckvalveineachline.TheMOYpositionindi-cationisprovidedinthecortrolroomancthesevalves.eceiveanopensignalcoincident,withthesafetyinjection(S;)signal.TheMOVsintheLPSIlinesopen,onanSIsignalbeforeRCSpressuredropsbe'owRHRdesignpressure.TheRequirements"thefol1owiag:(2)(3)plantccmpliestoallEIECaspec.softhe"RHRInterlockreviewcriterialistedinSection2ofthisreportexceptforTheplantRHRsystemdoesnotsatisfyBTPICSB3[Ref.13andBTPRSB5-1[Ref.23becausetheRHRdischargeandsuctionisolationMOYsdonothaveindependentdiverseinterlockstopreventopeningthevalvesuntilRCSpressureisbelow4'0psig.OnlytheinboardvalvesMGY-7GOandMGY-721havethisirterlock.TheoutboardvalvesMOY-701andMOY-720aremanuallycontrolledwithkey-lockedswit"hes.Byprocedure,MOV-701andMOY-720arenotopenedun.ilRCSpressureislessthan410psig.TheplanRHRsystemdoesnotsatisfyBTPICSB3[Ref.1jandBTPRSB5-1[Ref.23becauseallRHRisolationMOYslackanin.erlockfeaturetoclosethemwhenRCSpressureincreasesabovetheRHRdesignpressure.TheplantRHRsys.emdoesnotsatisyBTPICSB3[Ref.ljandBTPRSB5-1I.Ref.2]becausetheisolationMOVsintheLPSIlines(MOY-852AandMOY-852B)ooen.onanSIsignalbeforeRCSpressuredropsbelowRHRdesignpressure.

6.SUMMARYTheplantRHRinterlocksystemfailstosatisfycurrent.licensingcriteriaforthefollowingreasons:TheRHRsuctionanddischargeisolationMOVsdonothaveindependentdiverseinterlockstopreventopeningtheisolationMOYsuntilRCSpressureisbelow410pslgo(2)AllRHRisolationMOYslackaninterlockfeaturetoclosethemwhenRCSpressureincreasesaboveRHRdesignpressure.(3)TheisolationMOYsintheLPSIlinesopenonanSIsignalregardlessofRCSpressure.Theresolutionofitems1,2and3arepresentedinSections3.1and3.2ofSEPTopicV-ll.A.

REFERENCES1.U.S.NuclearRegulatoryCommission,BranchTechnicalPositionICSB3,"IsolationofLowPressureSystemsfromtheHighPressureReactorCoolantSystem."2.3.6.U.S.NuclearRegulatoryCommission,BrancnTechnical.PositionRSB5-1,"DesignRequirementsoftheResidualHeatRemovalSystem."NRC(0.M.Crutchfield)lettertoLLNL(M.H.Ditmore),datedJune10,1980.'Ginnadrawing,33013-436-A,"AuxiliarvCoolantSystem".~~SEPReviewofSafeShu.downSystemsfortheR.E.GinnaNuclearPowerPlant,Revision1,qnda~ed.Ginnadrawing,33013-432-A,"SafetyinjectionSystem."

APPENDIXANRCSAFETYTOPICSRELATEDTOTHISRPORT1III-1,"Classifica.ionofStructures,SystemsandComponents."2.III-10.A"ThermalOverloadofMOVs."3.Y-10-.B,"RHRSystemReliability."V-11.A,"RequirementsforIsolationofHighandLowPressureSystems."'.6.Y1-?.C"ECCSSingleFailureCriterionandRequiremen.sforLockingOutPowertoValvesIncludingIndependenceofInterlocksonECCSValves.."YIV.-3,"SvstemsRequiredforSa,eShutdown"?.XVI,"TechnicalSpecifications".

TOPICV-12,ASEETOPICII-4.E

TOPICV-0SEETOPICII-2.8

'~,A.HNENT=,~fg+je~~P'/ggROCHESTERCPSPHDELECTRICCORPORPTIOH:X~S9EASTAVEHUE,ROCHESTER,N.Y.I46<9~lollV<~'RiSI"EN7June23,1981DirectorofNuclearReactorRegulationAttention:Mr.DennisM.Crutchfield,ChiefOperatingReactorsBranch55U.S.NuclearRegulatoryCommissionwashington,D.C.20555c'~+oiciiciooc-io6'62OO~~l)1'ubject:SEPTopicsV-10.B,V-ll.A,V-11.B,VZ-7.C.1,VZZ-3,andVIIZ-2,R.E.pGinnaNuclearPowerPlantDocketNo.50-244

References:

(1)LetterfromDennisM.Crutchfield,NRC,toJohnE.Maier,RGE,SEPTopics,V-10.B,V-ll.B,andVZZ-3(SafeShutdownSystemsReport),May13,1981.(2)LetterfromDennisM.Crutchfield,NRC,toJohnE.Maier,RGE,SEPoicsV-11.A,V-11.B,andVZ-7.C.1,datedApril24,1981.(3)LetterfromDennisM.Crutchfield,NRC,toJohnE.Maier,RGE,SEPTopicsVIZ-3andVIII-2,datedApril2,1981.

DearMr.Crutchfield:

ThisletterisinresponsetotheSEPtopicassessmentsprovidedinthethreeabove-referencedletters.Duetotheintimaterelationshipofthe"SafeShutdown"topicsV-10.B,V-11.A,V-11.BandVZI-3addressedinthesethreeletters,allofourcommentsareprovidedconcurrentlyinthethreeattached'esponses.ThisshouldaidtheinclusionofourcommentsintotheNRC's"SEPIntegratedAssessment".rVerytrulyyours,ohnE.MaierAttachmentsr Attachment1:RG&EresponsestoNRCAssessment,ofSEPTopicsV-10.B,RHRSystemReliability,V-ll.B,RHRInterlockRequirements,andVII-3,SystemsRequiredforSafeShutdown(SafeShutdownSystemsreport),May13,1981.1.InRG&E'sJanuary13,1981responsetotheNRC'sNovember14,1980"SafeShutdownSystems"assessment,anumberofcommentsweremadewhichhavenotbeenincorporated.intoRevision2ofthisassessment,transmittedbyletterdatedMay13,1981.Wefeelthesecommentswerevalid,andshouldbeincorporated.Forcontinuity,thesecommentswillbelistedbelow(withtheiroriginalcommentnumbezs):assumespipingsystempassivefailures"...beyondthosenormallypostulatedbythestaff,e.g.,thecatastrophicfailureofmoderateenergysystems...".Althoughitisshownthatsafeshutdownfollowingsuchaneventcouldbeachieved,itisnotconsideredthatsuchanevaluationshouldevenbemade.Asnotedbythestaff,.itisclearlybeyondareasonabledesignbasis.Itisthusrecommendedthatthisparagraphbedeletedfromtheevaluation.Subsequentevaluationstothis"criterion",suchasthoserelatedtotheCCWsystemonpage22and23,shouldalsobedeleted.ll.Inparagraphgonpage66,itisnotedthat,wnena.plyingthepowerdiversityrequirementsofBT?ASB10-1'evento=anSSE,nomeanstosup}yfeedtothesteamgeneratorsexists.Itwascetezminedthatthiswasacceptable,basedonlowlikelihoodofoccurrence.Thisconclusioniscorrect;however,sinceBPTASB10-1doesnotconsideranSSEinconjunctionwiththelossofallA.C.power,thereisnoneedtoevenmaketheevaluation.ThecomparisonsintheSEPprogramshouldbetocurrentcriteria,ratherthantoarguableextrapo-lations.ReferencetolossofallA.C.powerinconjunctonwithanSSEshouldthusbedeletedfromthisparagraph.12.OnpageA-4,itisnotedthatadditionalsystemsarerequiredtoachievecoldshutdownforaPWRthanforaBWRbecauseofadifferenceinthedefinitionofcoldshutdown.Thisdoesnotappeartobeareasonablebasis.Systemrequirementsshouldbebasedonspecificsafetyreasons.TheNRCshouldbeconsistentin.itsrequirementsforcoldshutdown,ozprovideatechnicalbasisforanydifferences."

Staffposition1statesthat"thelicenseemustdevelopplantoperating/emergencyproceduresforconductingaplantshutdownandcooldownusingonlythesystemsandequipmentidentifiedinSection3.1oftheSEPSafeShutdownSystemsReport."RG&Edisagreeswiththeneedfortheseprocedures.WereiteratethecommentsprovidedinourJanuary13,1981responsethattheoperatorshouldperformacooldownwiththebestequipmentavailabletohimatthetime.Ifapieceofnon-safetyequipmentisavailable,andwouldbethemostbeneficialforperformingarequiredfunction,itisexpectedthatthispieceofequipmentwouldbeused.Ifitisnotavailable,theoperatorcouldfallbackontheuseofsafety-gradeequipment.ButRG&Edoesnotintendtocommitplantpersonneltouseonlysafety-relatedequipment,ifnon-safetyequipmentisavailableandmoreeffective.Wefeelthatitwouldbeimpossibletodeterminewhena"safety-grade-only"cooldownprocedurewouldeverbeimplemented.Aslongasthesafety-gradeequipmentisavailable(andthesafeshutdownassessmentconcudesthatitis),RG&Econsidersthatthenecessarysafetyrequirementsaremet.RG&Ealsonotesthatnoregulatorybasisforthisrequirementisprovided.ItisadmittedinSection4.5oftheSafeShutdownreportthat"theneedforproceduresfortheseevaluationsisnotidentifiedinRegulatoryGuide1.33..."~Section4.5thengoesontosaythatthebasisisfoundinBTPRSB5-1andSEPTopicVII-3.ButBTPRSB5-1merelyreferencesRG1.33,andthisistheassessmentofSEPTop'cVII-3.Therefore,sincenobasisforthis"requirement"exists,andwedonotfeelthatitwouldevenbebeneficial,andsincetheSafeShutdownreportdidconcludethatthecapabilityforattainingcoldshutdownusingonlysafety-relatedequipmentexists,RG&Econcludesthatthisstaffpositionshouldbedeletedfromconsideration.Staffposition3doesnotappeartotakeintoaccounttheinformationprovidedinourMarch27,1981submittalregardingSEPTopicV-ll.A.Enclosure3tothatsubmittalprovides'hevalveequipmentspecification,notingthatthe700,701,720and721NOV'saredesignedsuchthatthey'physicallyareunabletoopenagainstadifferentialpressureofgreaterthan500psi.ThisensuresthatanintersystemLOCAcausedbytheopeningoftheoutboardvalves,plusleakageoftheinboardvalves,cannotoccur,sincetheoutboardvalvescannotopen.

3Evenwithoutthisprovision,itisdifficulttocomprehendhowtheGinnaarrangementcouldresultinan"EventV".Byadministrativeprocedure,theRHRvalvesarekey-lockedclosed,withpowerremoved.Further,interlocksareprovidedfortheinboardRHRvalves.Thus,foran"EventV"tooccurwouldrequirethe:1)failureoftheadministrativeprocedurerequiringpowerlock-out(atthebreaker),2)failureoftheadministrativeproceduregoverningoperationofthevalveatpower,3)failureoftheinboardisolationvalve,4)failureofthereliefvalve(RV203)whichhasacapacityof70,000lb/hratits600psigsetpoint,torelievetheleakagepasttheinboardRHRvalve.Thissetoffailuresisconsideredveryremote.WhencoupledwiththefactthattheRHRvalvedesignpreventsopeningofthevalvesagainstagreaterthan500psidifferentialpressure,itisRG6E'sconclusionthatthepossibilityofanintersystemLOCAshouldnotbeacredibledesignbasis.Noadditionalmodifications,suchasdiverseinterlocks'fortheoutboardvalves,arewarranted.Staffposition5statesthat"theoperatingproceduresfortheGinnaplantshoulabemodifiedtodirecttheoperatortocooldownanddepressurizetoRHRinitiationparameterswithin36.hourswhenevertheServiceWaterSystemisusedforsteamgeneratorfeedwater..."ThispositionisbasedonthereferenceBNL-NUREG-28147,"ImpureWaterinSteamGeneratorsandIsolationCondensers."WehavehadthisreportreviewedbyNWTCorporation.NWT-167,"UseofLakeOntarioWaterinSteamGeneratorDuringHotShutdown"(attached)concludesthat,"althoughnotrecommendedfromthe-standpointofmaximizingcomponentlife,andoperationforperiodsuptoseveraldaysisnotexpectedtoresultinanysignificantcrackingorindeteriorationofsteamgenerator,integrity."tRG&EthereforeconcludesthataspecificdirectivetocooldownanddepressurizetoRHRinitiationconditionsisnot,.warranted,andshouldnotbeincludedinaprocedure.Thecapabilitytodothisdoesexist,however,andcouldbeusedifdeterminedtobenecessaryatthetime.

Attachment2:RG&EresponsestoNRCletterofApril24,1981regardingSEPTopicsV-11.A,"IsolationofHighandLowPressureSystems",V-11.B,"RHRInterlockRequirements",andVI-7.C.1,"IndependenceofRedundantOnsitePowerSystems".TheSafetyEvaluationforSEPTopicV-11.A,"Requirements,forIsolationofHighandLowPressureSystems",specifiesthattheoutboardRHRvalvesshouldhavediverseinterlockstopreventopeningwhentheRCSpressureisgreaterthanRHRsystemdesignpressure.2..RG&Erationalefornotprovidingtheseadditionalinterlocksisprovidedincomment3ofAttachment1ofthistransmittal.ThesafetyevaluationalsorequiredthatinterlocksbeinstalledontheCVCSsuctionvalves(200A,200B,202),topreventapossibleoverpressurizationoftheCVCSletdownlineoutsidecontainment.RG&EhasnotedinourMarch27,1981letteronthisSEPTopicthatareliefvalve(RV203),withacapacitygreaterthanthecombinedcapacityofthethreeorifices,wouldrelievethepressurebuildupcausedbyclosureofthecontainmentisolationvalve371.NooverpressurizationoftheCVCSwouldthusbeexpected.RG&Ehasalsoevaluatedthepotentialconsequencesofsuchanoverpressurizationevent,withasubsequentsmallLOCAoutsidecontainment,anddeterminedtha"nounacceptableconsequenceswouldresult.Thisbreak.wouldbeasmallLCCAoutsidecontainment(maximumflowof,140gpm),andwouldbeterminatedbyclosureofvalves200A,20GB,and202eitherbyoperatoractionorautomaticallybylowpressurizerlevel.Radiologicalconsequenceswouldbeminimal,sincenofueldamagewouldresult.Thiseventisspecificallyevalu-atedbySEPTopicXV-16,"RadiologicalConsequencesofFailureofSmallLinesCarryingPrimaryCoolantOutsideContainment."RG&EhasprovidedinformationconcerningthistopicbyletterdatedJune18,1980fromL.D.WhiteJr.toMr.DennisM.Crutchfield.TheRG&Econclusionisthat,basedonthe..availabilityofRV203topreventoverpressurization,togetherwiththelackofunacceptableconsequencesduetoanoverpressurization,nointerlocksorothermodificationsarerequiredfortheCVCSsuctionvalves.3.ThesafetyevaluationfurtherstatesthatpositionindicationisrequiredontheCVCSdischargecheckvalves.AsstatedinourMarch27,,1981letteronSEPTopicV-ll.A,wedonotbelievethatthislineshouldbeclassifiedasalowpressure systemconnectedtotheRCS,sincethepipingis2500-1bpipingthroughoutitslength(tothepositivedisplacementchargingpump).RG&Ehashadnoexperiencewithfailuresofthepositivedisplacementchargingpumppistonstoholdprimarysystempressure,norwouldanyfailuresbeanticipated.OurcontentionthatthecharginglineisnotalineofconcernisborneoutbyamemofromEdsonG.CasetoRaymond.F.Fraley,"IsolationofLowPressureSystemsfromReactorCoolantSystem",datedJuly11,1977.ThatlettertransmittedanNRCstudyofthissubjecttotheACRS,andevaluatedallpotentiallinesofconcern.Thecharginglinewasnotincluded.Toverifythatthecharginglinewasnotavalid"EventV"concern,RG&EcalculatedthePNRCneckValveEventTree(Section4.4ofWASH-1400),usingthecharginglinecon-figuration(twoin-seriescheckvalvesandachargingpumppiston).Veryconservativelyassumingthatbothcheckvalveswereundet'ectedopen,andthattheprobabilityofthechargingpump~istonfailurewasequaltoacheckvalvefailure,theQU>calculatedforthisconfigurationwasdeterminedto5e1.4x10/year.Thisisalowenoughvaluetoobviouslybeofnoconcern.RG&Ethereforeconsidersthatcheckvalvepositionindi-cationisnotneededonthecharginglinecheckvalves.iithrespecttotheS=P.opicAssessmentV-11.3,nocommentsarenecessary,sincetheresolutionofoutstandi..gissuesisaddressedinthetopicassessmen""orSEPŽpicV-3.3..A.TheadditionalinformationrequestedforSEPTopicVI-7.C.1ispresentlybeingdeveloped.ItisanticipatedthatthisinformationcanbefurnishedtotheNRCbyJuly15,1981.

Attachment3:RG&EresponsestoNRCletterofApril2,1981,concerningSEPTopicsVZI-3,"Electrical,Instru-mentation,andControlFeatureofSystemsRequiredforSafeShutdown",andVIII-2,"DieselGenerators".ZtappearsthatallcommentsprovidedbyRG&EinourJanuary23,1981andJanuary30,1981lettersconcerningthesetopicshavebeenproperlyincorporated.Basedontheresolutionofallopenitems,andtheremovalofdieselgeneratortestingfromSEPTopicVIII-2,RG&Econcludesthatbothofthesetopicsarecomplete,withnooutstandingissuestobecarriedintotheIntegratedAssessment.

NWT167February1981USEOFLAKEONTARIOWATERINSTEANGENERATORSDURINGHOTSHUTDOWNW.L.PearlS.E.CopieyJ~LelboVlKZPreparedfor'ochesterGas&E1ectricCompanyCorporation7015REALMDRIVE,SANJOSE,CALIFORNIA951198106800~

ThisdocumentwaspreparedfortheRochesterGas6ElectricCompany.NeithertheNWTCorporationnoranypersonactingonitsbehalfassumesanyresponsibilityforliabilityordamagewhichmayre'suitfromtheuseofanyinformationdisclosedinthisdocument.

INTRODUCTIONThepossibilityofusingLakeOntariowaterasanemergencyPWRfeedwatersupplyformorethan36hoursduringwhichtheplantwouldbebroughttocoldshutdownisbeingconsidered.Themaximumsteamingrateduringsuchaperiodwouldbe100,000pounds/h(200gpm)atatemperatureof350'F.Asaconsequenceofsteaming,impuritiesoftheuntreatedLakeOntariowaterwillconcentrateinthesteamgenerator.Ofmajorconcernisthepossibleriskofstresscorrosioncracking(SCC)ofsteamgeneratormaterialsincontactwiththeconcentratedsolutionthusformed.Toaddressthisconcern,thechemistryvariationintheliquidphaseassteamingproceedsat350'FwasestimatedwithemphasisonpH.Then,thepossiblepotentialforSCCwasassessedonthebasisoftheseestimatesandavailableSCCdata.

pHVARIATIONAT350'F'UPONSTEAMINGLAKEONTARIOWATERA.ComputerModelingThecompositionofLakeOntariowaterasdeterminedbyRGEisgiveninTable1.'ABLE1LAKEONTARIOWATERANALYSISppmCalciumtlagnesiumSodiumPotassiumAluminumChlorideSulfate358133.60~13235NitratePhosphateFluorideSi1ica(asSi02)DissolvedOxygenAmmonia(asNitrogen)2.50.30.150.259.50.24Estimatesofthewaterchemistryvariationuponsteamingweredevelopedusingthefollowingassumptions:1.SincealuminumandsilicaareinstoichiometricproportioninLakeOntariowater(Table1),theyareassumedtoprecipitateasaluminumsilicate(clay)uponconcentrating'andthereforeareremovedfromsolution.2.Sincecalciumoccursinthewater(Table1)inlargeexcessoverphosphate,itisassumedtoprecipitateallthephosphateascalciumhydroxyapatite(Ca5(P04)30H)andremoveitfromthesolution.Thecalciuminsolutionisdecreasedbythecorrespondingamount.3.Fluorideandnitriteareassumedtobehaveaschloride.Potassiumisassumedtobehaveassodium.4.Sodiumandchlorideinsolutionareassumedtoremaincompletely.dissociated.5=Calciumcarbonateprecipitationisneglected.DegasificationofCO~bysteamingisassumedtooccur.

6.Theconcentrationofsodiumandcalciumchloridesisassumedlimitedbyasolubilityof5molal.7.Chemicalequilibriumexpressionsofreferences2and3apply.Onthisbasis,theliquidsolutionpHvariationuponsteamingat350'Fwasestimatedasafunctionofconcentrationfactordefinedasthemassratiooftotalwater(steam+liquid)toliquidwaterresidual.TheresultsarepresentedgraphicallyinFigure1.Itisimportanttonote'thatthedefinitionofpHusedhereisthatfollowedbyMesmer"inthedeterminationofthedissociationconstantofwaterathightemperatures,viz,thenegativeofthelogarithmofthehydrogenionconcentration(notofitsactivity).Similarly,neutralpHisdefinedasthatwherethehydrogenandhydroxylionconcentrationsareequal.ThisneutralpHisafunctionofionicstrength.Therefore,thepHvariationoftheconcentratedsolutionsmustbeconsideredinrelationtothatofneutralpH,alsoplottedinFigure1.Forbasicsolutionsasisthecaseconsideredhere,itisimportanttobearinmindthat.hehydroxylionconcentrationisexpressedintermsopHasfollows:=10pH2NpHOH(whereNpHistheneutralpHvalue)andthatwhentheneutralpHvariestogetherwiththeionicstrengthastheliquidsolutionisbeingconcentrateduponsteaming,thebasicityofthesolutionmaynotbeappreciatedfromthesolutionpHalone.TheequivalentNaOHconcentrationismoresuitableforthispurposeandisplottedalsoinFigurel.B.DiscussionSteamGeneratorBulkWaterBased.onamaximumfeedrateof200gpmtothesteamgeneratorandatotalsteamgeneratorliquid'nlumeofapproximately12,000gallons,amaximumofonesteamgeneratorvolumeissteamedawayeachhour.Therefore,undermaximumsteaming-~onditions,theconcentrationfactorachievedinthebulksteamgeneratorwaterist+1wheretisthenumberofhoursofsteaming.

SolutionpH00IIEquivalentNaOHConcentrationNeutralpH~400o)Ozoo05Ptft0200810010100100010000Time~ll3Figure1.VariationofSteamGeneratorpHwitHSteamingat350'F(feedingLakeOntariowaterat200gpm)

ThevariationwithtimeoftheequivalentsodiumhydroxideconcentrationinthesteamgeneratorwithsteamingofemergencyLakeOntariofeedwaterthencanbefollowedonFigure1.ItisseenthatamaximumequivalentNaOHconcentrationofabout300ppmwillbereachedinthesteamgeneratorbulkwaterwhen15to20steamgeneratorvolumeswillhavebeenconvertedtosteam,i.e.,inapproximatelytwentyhours.FurtherboilingshouldthendecreasetheequivalentNaOHconcen-trationasmagnesiumand/orcalciumhydroxidesand/orcalciumsulfateprecipitatewithincreasedconcentrating.Thedecreasereachesalimit(atabout20,000steamgeneratorvolumesconvertedtosteam,i.e.,in20,000hours)whensodiumandcalciumchloridesstarttoprecipitatealso.Thislimitisestimatedatabout100ppmequivalentNaOHforLake)OntariowatercompositionasspecifiedinTable1andwiththeassumptionsalreadystated.Theassumptionsseemreasonableand,atanyrate,canbetestedexperimentallywithasmallautoclavefromwhichknownamountsofLakeOntariowaterwouldbeboiledawayat350'Fatconstantliquidlevelinthyautoclave.CrevicesTheestimatedequivalentNaOHsolutionconcentrationinsteamgeneratorcreviceswilldependupontherelativedegreeofcrevicesolutionconcentrationabovethebulkwater.Intubetotubesupportplatecrevices,theremaybeadistributionofrelativeconcentrationfactorsofunityandhigher.Thechemistryinacrevicewouldleadthatofthebulkinthesensethatthechemistryofaspecificcrevicewouldtravelthesamecurve(Figure1)asthebulkbutwouldbeatapointonthe.curvesomewhataheadofthebulk.Since1thecausticityofLakeOntariowaterisnotastrongfunctionofconcentration,thisdoesnotposeaproblem.Indeeditisexpectedinthiscasethatafterashortperiodofsteaming,thecrevicechemistrywillbe'essbasicthanthatofthebulk.CoolinWaterComositionTheNWTchemistrymodelingworkdiscussedhereinisbasedonthechemicalcompositionofLakeOntariowatersummarizedinTable1assuppliedbyRGE.

Itispossiblethatseasonalchangesinthecharacteristics'fthelakewatermayresultfromtheinterrelationbetweensourceriverflowrates,industrialpollutionand/oracidrain.NWThasnorelevantdatatoassesssucheffects.ItmaybedesirablethatanalysesmadeofLakeOntariowaterduringdifferentseasonsandundervariousconditionsbefedintotheNWTchemistrymodel.InthismannerthesafetyoffeedingLakeOntariowater,overtherangeoflikelychemicalcompositions,canbeverified.6 POTENTIALFORSCCA.CorrosionThemostaggressivesolutionexpectedbasedonthemodelingworkis300ppmNaOH,withslOppm02(seebelow)at350'F.Althoughlaboratorydataregardingtheseexactconditionsarenotavailable,dataareavailablewhichcanbeextrapolatedtoassessthemaximumcorrosionratesexpectedforagivenrangeofconditions.vanRooyenandKendig~citeWestinghousedataindicatingthatU-bendsofAlloy600indeaerated10~NaOHcrackafterseveralmonthsofexposure.Figures2and'3summarizeWestinghousetests'hichshowthatatleast100daysofexposuretodeaerated10%NaOHat600'FisrequiredtoproduceadetectablecrackinstressedAlloy600.Figure4showsdatagatheredbvBerceandOonat',.'hesecurvesareforyieldstressedCringsat660'F.extrapolatingthe.curveformillannealedAlloy600to300ppmNaOHyieldsaminimumtimeof3500-4000hourstoinduce5millimetercrack.ThedatapresentedabovearefordeaeratedsystemsandareconsistentwithvanRooyen's'onclusionthatAlloy600in10%NaOHwouldnotcrackforseveralmonths.Inthepresenceofoxygen,thesusceptibilityofAlloy600toSCCmaybeincreased.Figure5showsstresscorrosionbehaviorin600'Fhighpuritywatercontainingvaryingamountsofoxygeninthegas'phaseabovethewaterandadjustedtopH10atstartupwithammonia.As'theoxygencontentofthegasphaseincreased,thepercentofthespecimensattackedandextentof'heattackincreased.AsnotedinFigure5theaveragelifeinthe18-weektestvariedfromnocrackingwith15oxygeninthegasphase(<2ppmoxygeninthewater)to7weekswith100~oxygeninthegasphase(<200ppmoxygeninthewater).McIlreeandMichelsandlaterSedriks,etal.,'eportedlessthan.20Kcrackingafter27daysforAlloy600(2commonheattreatments)inaerated,50<NaOHat570'F.7~

Cg.aa.I00Wrslasnm<aTgrlXIUIIIIIXIIV.AJaalTheeeenranneeieglraaaea~~0itg'Rnse01XCO41SIcKnKCOCsoesureTleeIhrssFigure2.CrackDepthasaFunctionofTime,StressLevelandMaterialConditionforIDPressurized,CapsulesExposedtoDeaerated10~NaOHat600'FL56LAea0.3LTHeat'%CMATT9COT.0111901.OTT150.03l7343.OQ310CC&nTs11500yleMIMIIIAnnealed.01ae0'eg.01aaO.ITTIarinallytCOTTsponsreTlaie1nrsl~eeesTreetssl'Figure3.CrackOepthasaFunctionofgxlIosureTimeforMillAnnealedandThermallyTreatedInconelAlloy600ExposedtoDeaerated10KNaOHat600'F' 4000CRingsStressedtoa=YsAccordingtoASTMSTP42530002000Al1oy600HT16h1300'F1000Al1oy600MA01,00010,000100,000NaOHConcentration,ppmFigure4.Resistanceto-StressCorrosionCrackingofAlloy600Mi11-AnnealedorHeatTreatedat1300'FasaFunctionofDeaeratedSodiumHydroxideConcentrationat600'F~

II'20NO.OFSPECIMENS,MILLANN.8PERCENTCRACKEO0AVLIFEINIBWEEKTESTSIBAVOFMAX.CRACKDEPTHS,MIL00IB'0'201801258172ll29?I550l2IOO,752oo~IOOO'Z80I-i:60Zgro+)40.CI'"20j80ieieisisieieieieisieisisIlOlOlAIIPIAIAIRtIAAieI18isi8IRi88Ii2'l2OXYGENINGASATSTART,(%)NILALLOY600HEATN27B542NIL47B25647B256478256476256IOO21BALANCEOFGAS,HYOROGENARGOhkNITROGENNITROGENAIRFigure5.StressCorrosionBehaviorinCreviceAreasinMillAnnealedEnconel600OoubleU-bendSpecimensin600'FHighPurityWaterAdjustedtopH10withAmmoniaatStartup'0 LaboratorystudiesshowthatthereisasignificanttemperaturedependenceofcausticstresscorrosioncrackingasillustratedinFigures6and7.Theseresultsareforpressurizedcapsulesexposedto105and50%NaOHatvaryingstressesattemperaturesrangingfrom650to550'F.Ascanbeseen,reducingthetemperaturebelow600'FsignificantlyextendsthetimeforSCCtooccur.ThistemperaturedependenceisfurtherillustratedinFigure8wheretemperatureisplottedversusrateconstantforboth10Kand505NaOH.8.OxygenThelakewaterfedtothegeneratorsprobablywouldbeairsaturated(approximateiy'.0opm0>).However-,at350'FtheKO(theequilibriumratiobetweensteamphaseandliquidphase)foroxygenisslightlygreaterthan5000.Eventhoughthedynamicdistributioninpracticemaynotreachtrueequilibriumconditions,theneteffectofthehighKOvalueisthatrecriculatedsteamgeneratorcoolant~Iillcontainoxygenconcentrationslowerthan10ppm.Thisrecirculatedcoolantwil':dilutetheoxygenconcentrationofincomingfeedwatrwithanetoxygenlevelinthedowncomerof~1to10ppm,dependingontlerecirculationratiounderthecontingencyconditions.C.Conclusion~Withthesignificantlylowerconcentrationsofsodiumhydroxide(max30oppm),oxygenconcentration<10ppmandthelowertemperature(350'F)involved,tIie~o~tingencyoffeedingLakeOntariowatertotheGinnasteamgeneratorsshouldresultinnomeasureabledamagetosteamgeneratorinternals.Although'otrecommendedfromthestandpointofmaximizingcomponentlife,suchoperat~o~forperiodsuptoseveraldaysisnotexpectedtoresu1tinanysignificant.crackingorinadeteriorationofsteamgeneratorintegrity.11 NaOH50X10X575'Fg0.5to5mils504030>10mils')05to10mils100.5to5mils01000200030004000500060007000ExposureTime,hrsFigure6-.CausticCrackingofHillAnnealedAlloy600at575'F(LinesdepictzonesofcrackdepthfromlOXNaOHat600F)12 NaOH50Z10X550'70<0.5mils0.5to5milsg0.5to5mils50XNaOH650p504030nm20>10mils5to10mils00100.5to5mils0100020003000400050006000ExposureTime,hrsFigure7.CausticCrackingofMillAnnealedAlloy600at55and650'F]Linesdepictzonesofcrackdepth<<omNaOHat600'F)13 200~IMAI-600150CKIV4JtC)Ct0ZsIU0)CI100500530550570590610630Temperature,FFigure8.IndicatedVariationinRateofSCCwithTemperature14

~~~i'r.:.L.IEEICOMMENTSONYANROQ'fENANOyE!;0:O'5REPORT'Thereferencedreportsbasica11v:-.ibroadsummarycoveringalargevolumeofdataapplicable,inpartto..~:rl.sssteelsandinparttoAlloy600.get>$Earegene~allyinagreementwith.'.e'rninesummaryconclusions,butfinditdifficulttoapplytheirbroad-br>qntreatmenttothespecificsofapMRhotshutdownwithlakewateraddedto..hesteamgeneratorsat350'F.TheirdocumentEEE~~fismisleadingforsuchanapplicationintworespects:LE~~\E1.CausticConcentrationTheirstatementthat..."For.".,-;rposesofSCCpredictions,ithastobeassumedthatthetimeto.'c."..:ngerouslevelsofNaOH,onceimpuritieshavebeenintroduced,isshor:.:.=.,onedayorless"doesnotfullyrecognizethespecificconcen.r'.:.nchemistryofthecoolingwaterinvolvednorthelowheat'.lux::;'.i'ableandthecutbackinsteamingrateduringaperiodofhotshutcown.'"thecaseoftheLakeOntariowaterforexample,themaximumNaCH...""-=.".-raw'.onreachedis300ppm(aftersteaming~20steamgenerator-"-';withadecreaseinconcentrationthereafter.2.TemperatureEAllofthetestworkreferencedin-hereferencedreport~wasperformedir.thetemperaturerangeof550to=-:G=F.WiththesignificanttemperaturedependenceofcausticSCCasshownabove,theconcernat350Fismanyti~slessthanisindicatedfnmthe,dataquotedbytheauthors.Basedontheabovethreeconsiderations.itisourassessmentthatthegeneralizedtimelimitof36hoursi,=.'"ereport~isnotdirectlyapplicabletotheGinnasteamgeneratorssteamin.at350'FwhilefedbyLakeOntariowater.15~rtE

.REFERENCESHarhay,A.,RochesterGas8Electric,personalCommunication,Februaryll,.1981.2.3.5.Leibovitz,J.,andSawochka,S.G.,"ModelingtheEffectsofCondenserInleakageonPWRChemistry",presentedat41stAnnualInternationalMaterConference,Pittsburgh,Pennsylvania,October1980.Leibovi;tz,J.andSawochka,S.G.,"ModelingofCoolingWaterInleakageEffectsinPWRSteamGenerators,TopicalReport,ResearchProject404-1",Elec'tricPowerResearchInstitute,May1980,tobepublished.Mesmer,R.E.,Baes,C.F.,Jr.,andSweeton,F.M.,"BoricAcidEquilibriaandpHinPWRCoolants',Proceedingsofthe32ndInternationalMaterCon-ference,Pittsburgh,P~nnsylvania,November1971,pp.55-65.vanRooyen,D.,andKesdig,M.W.,"ImpureWaterinSteamGeneratorsandIsolationGenerators",BrookhavenNationalLaboratory,June1980(Draft-BNL-NUREG-28147).7.8.9.10.Airey,G.P.,"EffectofProcessingVariablesontheCausticStressCorrosionResistanceofInconelAlloy600",presentedatNACEMeeting~March1979(PaperNumber101).Berge,Ph.andDonati,J.R.,"MaterialsRequirementsforSteamGeneratorTubing",presentedatInternationalConferenceonMaterialsperformanceinNuclearSteamGenerators,St.Petersburg,Florida,October1980.Copson,H.R.andEconomy,G.,"EffectofSomeEnvironmentalConditionsonStressCorrosionBehaviorofNi-Cr-FeAlloysinPressurizedWater'Corrosion,24,No.3,pp.55-65(March1968).McIlree,A.R.andMichels,H.T.,"StressCorrosionBehaviorofFe"<<->>andOtherAlloysinHighTemperatureCausticSolutions",.Corr'osion.33.No;2,pp.60-67(February1977).Sedriks,A.J.,etal.,"InconelAlloy690-ANewCorrosionResistantMaterial",'CorrosionEngineering(Japan),28,No.2,pp.82-95(1979).4Burstein,.S.,WEPCO,ltrtoH.R.Denton,NRC,dtdNovembe~23~withattachments.

.,ACHMENT'P%rtROCHESTERGASANDELECTRICCORPORATION'.Z~89EASTAVENUE,ROCHESTER,N.Y.14649June23,1981DirectorofNuclearReactorRegulationAttention:Mr.Dennis.M.Crutchfield,ChiefOperatingReactorsBranch55U.S.NuclearRegulatoryCommissionNashington,D.C.20555C!>>O'ICi~NiOaC-io,5-'9-2~OO-1(p

Subject:

SEPTopicsV-10.B,V-ll.A,V-ll.B,VI-7.C.lgVZX-3,andVIII-2,R.E.GinnaNuclearPowerPlantDocketNo.50-244

References:

(1)LetterfromDennishi.Crutchfield,NRC,toJohnE.Maier,RGE,SEPTopics,V-10.B,V-ll.B,andVII-3(SafeShutdownSystemsReport),May13,1981.(2)Lette"fromDennisM.Crutchfield,NRC,toJohnE.Maier,RG"gSEPopicsV-ll.A,V-ll.B,ancVX-7.C.lfdatedApril24,1981.(3)LetterfromDennisM.Crutchfield,NRC,toJohnE.Maier,RGE,SEPTopicsVII-3andVIII-2,datedApril2,1981.

DearMr.Crutchfield:

ThisletterisinresponsetotheSEPtopicassessmentsprovidedinthethreeabove-referencedletters.Duetotheintimaterelationshipofthe"SafeShutdown"topicsV-10.B,V-ll.A,V-ll.BandVII-3addressedinthesethreeletters,allofourcommentsareprovidedconcurrentlyinthethreeattached'espon'ses.ThisshouldaidtheinclusionofourcommentsintotheNRC's"SEPXntegratedAssessment".AttachmentsVerytrulyyours,ohnE.Maier+~sI/i8106300'3M Attachment1:RGSEresponsestoNRCAssessmentofSEPTopicsV-10.B,RHRSystemReliability,V-11.B,RHRInterlockRequirements,andVII-3,SystemsRequiredforSafeShutdown(SafeShutdownSystemsreport),May13,1981.1.InRG&E'sJanuary13,1981responsetotheNRC'sNovember14,1980"SafeShutdownSystems"assessment,anumberofcommentsweremadewhichhavenotbeenincorporatedintoRevision2ofthisassessment,transmittedbyletterdatedMay13,1981.Wefeelthesecommentswerevalid,andshouldbeincorporated.Forcontinuity,thesecommentswillbelistedbelow(withtheiroriginalcommentnumbers):Onpage5,PiinSstemPassiveFailures,theNRCassumespipingsystempassivefailures"...beyondthosenormallypostulatedbythestaff,e.g.,thecatastrophicfailureofmoderateenergysystems...".Althoughitisshownthatsafeshutdownfollowingsuchaneventcouldbeachieved,itisnotconsideredthatsuchanevaluationshouldevenbemade.Asnotedbythestaff,itisclearlybeyondareasonabledesignbasis.Itisthusrecommendedthatthisparagraphbedeletedfromtheevaluation.Subsequentevaluationstothis"criterion",suchasthoserelatedtotheCCWsystemonpage22and23,shouldalsobedeleted.1nparagraphgonpage66,itisnotedthat,wnenaplvingthepowerdiversityrequirementsofBT?ASB10-1ineventofanSSE,nomeanstosuplyfeedtothesteamgeneratorsexists.Itwasdeterminedthatthiswasacceptable,basedonlowlikelihoodofoccurrence.12'.Thisconclusioniscorrect;however,sinceBPTASB10-1doesnotconsideranSSEinconjunctionwiththelossofallA.C.power,thereisnoneedtoevenmaketheevaluation.ThecomparisonsintheSEPprogramshouldbetocurrentcriteria,ratherthantoarguableextrapo-lations.ReferencetolossofallA.C.powerinconjunctonwithanSSEshouldthusbedeletedfromthisparagraph.OnpageA-4,itisnotedthatadditionalsystemsarerequiredtoachievecoldshutdownforaPWRthanforaBWRbecauseofadifferenceinthedefinitionofcoldshutdown.Thisdoesnotappeartobeareasonablebasis.Systemrequirementsshouldbebasedonspecificsafetyreasons.TheNRCshouldbeconsistentin.itsrequirementsforcoldshutdown,orprovideatechnicalbasisforanydifferences."

Staffposition1statesthat"thelicenseemustdevelopplantoperating/emergencyproceduresforconductingaplantshutdownandcooldownusingonlythesystemsandequipmentidentifiedinSection3.1oftheSEPSafeShutdownSystemsReport."RG&Edisagreeswiththeneedfortheseprocedures.WereiteratethecommentsprovidedinourJanuary13,1981responsethattheoperatorshouldperformacooldownwiththebestequipmentavailabletohimatthetime.Ifapieceofnon-safetyequipmentisavailable,andwouldbethemostbeneficialforperformingarequiredfunction,itisexpectedthatthispieceofequipmentwouldbeused.Ifitisnotavailable,theoperatorcouldfallbackontheuseofsafety-gradeequipment.ButRG&Edoesnotintendtocommitplantpersonneltouseonlysafety-relatedequipment,ifnon-safetyequipmentisavailableandmoreeffective.Wefeelthatitwouldbeimpossibletodeterminewhena"safety-grade-only"cooldownprocedurewouldeverbeimplemented.Aslongasthesafety-gradeequipmentisavailable(andthesafeshutdownassessmentconcudesthatitis),RG&Econsidersthatthenecessarysafetyrequirementsaremet.RG&Ealsonotesthatnoregulatorybasisforthisrequirementisprovided.ItisadmittedinSection4.5oftheSafeShutdownreportthat"theneedforproceduresfortheseevaluationsisnotidentifiedinRegulatoryGuide1.33...".Section4.5thengoesontosaythatthebasisisfoundinBTPRSB5-1andSEPTopicVII-3.ButBTPRSB5-1merelyreferencesRG1.33,andthisistheassessmentofSEPop'cVII-3.Therefore,sincenobasisforthis"requirement"exists,andwedonotfeelthatitwouldevenbebeneficial,andsincetheSafeShutdownreportdidconcludethatthecapabilityforattainingcoldshutdownusingonlysafety-relatedequipmentexists,RG&Econcludesthatthisstaffpositionshouldbedeletedfromconsideration.Staffposition3doesnotappeartotakeintoaccounttheinformationprovidedinourMarch27,1981submittalregardingSEPTopicV-11.A.Enclosure3tothatsubmittalprovides'hevalveequipmentspecification,notingthatthe700,701,720and721MOV'saredesignedsuchthatthey:physicallyareunabletoopenagainstadifferentialpressureofgreaterthan500psi.ThisensuresthatanintersystemLOCAcausedbytheopeningoftheoutboardvalves,plusleakageoftheinboardvalves,cannotoccur,sincetheoutboardvalvescannot,open.

~~Evenwithoutthisprovision,itisdifficulttocomprehendhowtheGinnaarrangementcouldresultinan"EventV".Byadministrativeprocedure,theRHRvalvesarekey-lockedclosed,withpowerremoved.Further,interlocksareprovidedfortheinboardRHRvalves.Thus,foran"EventV"tooccurwouldrequirethe:1)failureoftheadministrativeprocedurerequiringpowerlock-out(atthebreaker),2)failureoftheadministrativeproceduregoverningoperationofthevalveatpower,3)failureoftheinboardisolationvalve,4)failureofthereliefvalve(RV203)whichhasacapacityof70,000lb/hratits600psigsetpoint,torelievetheleakagepasttheinboardRHRvalve.Thissetoffailuresisconsideredveryremote.WhencoupledwiththefactthattheRHRvalvedesignpreventsopeningofthevalvesagainstagreaterthan500psidifferentialpressure,itisRG&E'sconclusionthatthepossibilityofanintersystemLOCAshouldnotbeacredibledesignbasis.Noadditionalmodifications,suchasdiverseinterlocksfortheoutboardvalves,arewarranted.Staffposition5statesthat"theoperatingproceduresfortneGinnaplantshouldbemodifiedtodirecttheoperatortocooldownanddepressurizetoRHRinitiationparameterswithin36hourswhenevertheServiceWaterSystemisusedforsteamgeneratorfeedwater..."ThispositionisbasedonthereferenceBNL-NUREG-28147,"ImpureWaterinSteamGeneratorsandIsolationCondensers."WehavehadthisreportreviewedbyNWTCorporation.NWT-167,"UseofLakeOntarioWaterinSteamGeneratorDuringHotShutdown"(attached)concludesthat,"althoughnotrecommendedfromthestandpointofmaximizingcomponentlife,andoperationforperiodsuptoseveraldaysisnotexpectedtoresultinanysignificantcrackingorindeteriorationofsteamgenerator.integrity."RG&EthereforeconcludesthataspecificdirectivetocooldownanddepressurizetoRHRinitiationconditionsisnot,.warranted,andshouldnotbeincludedinaprocedure.Thecapabilitytodothisdoesexist,however,andcouldbeusedifdeterminedtobenecessaryatthetime.

Attachment2:RG&EresponsestoNRCletterofApril24,1981regardingSEPTopicsV-ll.A,"IsolationofHighandLowPressureSystems",V-11.B,"RHRInterlockRequirements",andVI-7.C.1,"IndependenceofRedundantOnsitePowerSystems".TheSafetyEvaluationforSEPTopicV-11.A,"RequirementsforIsolationofHighandLowPressureSystems",specifiesthattheoutboardRHRvalvesshouldhavediverseinterlockstopreventopeningwhentheRCSpressureisgreaterthanRHRsystemdesignpressure.RG&Erationalefornotprovidingtheseadditionalinterlocksisprovidedincomment3ofAttachment1ofthistransmittal.2.ThesafetyevaluationalsorequiredthatinterlocksbeinstalledontheCVCSsuctionvalves(200A,200B,202),topreventapossibleoverpressurizationoftheCVCSletdownlineoutsidecontainment.RG&EhasnotedinourMarch27,1981letteronthisSEPTopicthatareliefvalve(RV203),withacapacitygreaterthanthecombinedcapacityofthethreeorifices,wouldrelievethepressurebuildupcausedbyclosureofthecontainmentisolationvalve371.NooverpressurizationoftheCVCSwouldthusbeexpected.RG&Ehasalsoevaluatedthepotentialconsequencesofsuchanoverpressurizationevent,withasubsequentsmallLOCAoutsidecpntainment,anddeterminedtha"nounacceptableconsequenceswouldresult.ThisbreakwouldbeasmallLCCAousideconta'ment(maximumlowof,140gpm),andwouldbeterminatedbyclosureofvalves200A,20GB,and202eitherbyoperatoractionorautomaticallybylowpressurizerlevel.Radiologicalconsequenceswouldbeminimal,sincenofueldamagewouldresult.Thiseventisspecificallyevalu-atedbySEPTopicXV-16,"RadiologicalConsequencesofFailureofSmallLinesCarryingPrimaryCoolantOutsideContainment."RG&EhasprovidedinformationconcerningthistopicbyletterdatedJune18,1980fromL.D.whiteJr.toMr.DennisM.Crutchfield.TheRG&Econclusionisthat,basedonthe..availabilityofRV203topreventoverpressurization,togetherwiththelackofunacceptableconsequencesduetoanoverpressurization,nointerlocksorothermodificationsarerequiredfortheCVCSsuctionvalves.3.ThesafetyevaluationfurtherstatesthatpositionindicationisrequiredontheCVCSdischargecheckvalves.AsstatedinourMarch27,1981letteronSEPTopicV-11.A,wedonotbelievethatthislineshouldbeclassifiedasalowpressure systemconnectedtotheRCS,sincethepipingis2500-1bpipingthroughoutitslength(tothepositivedisplacementchargingpump).RG&Ehashadnoexperiencewithfailuresofthepositivedisplacementchargingpumppistonstoholdprimarysystempressure,norwouldanyfailuresbeanticipated.OurcontentionthatthecharginglineisnotalineofconcernisborneoutbyamemofromEdsonG.CasetoRaymondF.Fraley,"IsolationofLowPressureSystemsfromReactorCoolantSystem",datedJuly11,1977.ThatlettertransmittedanNRCstudyofthissubjectto'heACRS,andevaluated"allpotentiallinesofconcern.Thecharginglinewasnotincluded.Toverifythatthecharginglinewasnotavalid"EventV"concern,RG&EcalculatedthePWRCheckValveEventTree(Section4.4ofWASH-1400),usingthecharginglinecon-figuration(twoin-seriescheckvalvesandachargingpumppiston).Veryconservativelyassumingthatbothcheckvalveswereundetectedopen,andthattheprobabilityofthechargingpump~istonfailurewasequaltoacheckvalvefailure,theQU>calculatedforthisconfigurationwasdeterminedto5e1.4x10/year.Thisisalowenough,valuetoobviouslybeoznoconcern.RG&Ethereforeconsidersthatcheckvalvepositionindi-cationisnotneededonthecharginglinecheckvalves.~;ithrespecttotne="=P.opicAssessmentV-11.3,nccommen"sarenecessary,sincetheresolutionofoutstanci..gissuesisaddressedintietopicassessr..en"orSEPepicV-ll.A.TheadditionalinformationrequestedforSEPTopicVI-7.C.1ispresentlybeingdeveloped.ItisanticipatedthatthisinformationcanbefurnishedtotheNRCbyJuly15,1981.

Attachment3:RG&EresponsestoNRCletterofApril2,1981,concerningSEPTopicsVII-3,"Electrical,Instru-mentation,andControlFeatureofSystemsRequiredforSafeShutdown",andVIII-2,"DieselGenerators".ItappearsthatallcommentsprovidedbyRGSEinourJanuary23,1981andJanuary30,1981lettersconcerningthesetopicshavebeenproperlyincorporated.Basedontheresolutionofallopenitems,andtheremovalofdieselgeneratortestingfromSEPTopicVIII-2,RG6Econcludesthatbothofthesetopicsarecomplete,withnooutstandingissuestobecarriedintotheIntegratedAssessment.

NWT167February1981tUSEOFLAKEONTARIOWATERINSTEAMGENERATORSDURINGHOTSHUTDOWNW.L.PearlS.E.CopleyJ.LeibovitzPreparedfoiRochesterGas&ElectricCompanyCorporation7015REALMORIVE.SANJOSE,CALIFORNIA95119 ThisdocumentwaspreparedfortheRochesterGas&ElectricCompany.Neitherthe%/TCorporationnoranypersonactingonitsbehalfassumesanyresponsibilityforliabilityordamagewhichmayresultfromtheuseofanyinformationdisclosedinthisdocument.

INTRODUCTIONThepossibilityofusingLakeOntariowaterasanemergencyPWRfeedwatersupplyformorethan36hoursduringwhichtheplantwouldbebroughttocoldshutdownisbeingconsidered.Themaximumsteamingrateduringsuchaperiodwouldbe100,000pounds/h(200gpm)atatemperatureof350'F.Asaconsequenceofsteaming,impuritiesoftheuntreatedLakeOntariowaterwillconcentrateinthesteamgenerator.Ofmajorconcernisthepossibleriskofstresscorrosioncracking(SCC)ofsteamgeneratormaterialsincontactwiththeconcentratedsolutionthusformed.Toaddressthisconcern,thechemistryvariationi'ntheliquidphaseassteamingproceedsat3k'FwasestimatedwithemphasisonpH.Then,thepossiblepotentialforSCCwasassessedonthebasisoftheseestimatesandavailableSCCdata.

.pHVARIATIONAT350'FUPONSTEAMINGLAKEONTARIOWATER,A.ComputerModelingThecompositionofLakeOntariowaterasdeterminedbyRGEisgiveninTablel.'ABLE1LAKEONTARIOWATERANALYSISppm~IIII'alciumMagnesiumSodiumPotassiumAluminumChlorideSulfate35133.60.13235NitratePhosphateFluorideSilica(asSi02)DissolvedOxygenAmmonia(asNitrogen)2.50.30.150.259.50.24Estimatesofthewaterchemistryvariationuponsteamingweredevelopedusingthefollowingassumptions:1.SincealuminumandsilicaareinstoichiometricproportioninLakeOntariowater(Table1),theyareassumedtoprecipitateasaluminumsilicate(clay)uponconcentrating'andthereforeareremovedfromsolution.2.Sincecalciumoccursinthewater(Table1)inlargeexcessoverphosphate,itisassumedtoprecipitateallthephosphateascalciumhydroxyapatite(Ca5(P04)30H)andremoveitfromthesolution.Thecalciuminsolutionisdecreasedbythecorrespondingamount.3.Fluorideandnitriteareassumedtobehaveaschloride.Potassiumisassumedtobehaveassodium.4'.Sodiumandchlorideinsolutionareassumedtoremaincompletely.dissociated.5=Calciumcarbonateprecipitationisneglected.DegasificationofCO~bysteamingisassumedtooccur.

6.Theconcentrationofsodiumandcalciumchloridesisassumedlimitedbyasolubilityof5molal.7.Chemicalequilibriumexpressionsofreferences2and3apply.Onthisbasis,theliquidsolutionpHvariationuponsteamingat350'Fwasestimatedasafunctionofconcentrationfactordefinedasthemassratiooftotalwater(steam+liquid)toliquidwaterresidual.TheresultsarepresentedgraphicallyinFigurel.ItisimportanttonotethatthedefinitionofpHusedhereisthatfollowedbyMesmer"inthedeterminationofthedissociationconstantofwaterathightemperatures,viz,thenegativeofthelogarithmofthehydrogenionconcentration(notofitsactivity).Similarly,neutralpHisdefinedasthatwherethehydrogenandhydroxylionconcentrationsareequal.ThisneutralpHisafunctionofionicstrength.Therefore,thepHvariationoftheconcentratedsolutionsmustbeconsideredinrelationtothatofneutralpH,alsoplottedinFigure1.Forbasicsolutionsasisthecaseconsideredhere,itisimportanttcbearinmindthat.hehydroxylionconcentrationisexpressedintermsopHasfollows:10pH-2NpHOH(whereNpHistheneutralpHvalue)andthatwhentheneutralpHvariestogetherwiththeionicstrengthastheliquidsolutionisbeingconcentrateduponsteaming,thebasicityofthesolutionmaynotbeappreciatedfromthesolutionpHalone.TheequivalentNaOHconcentrationismoresuitableforthispurposeandisplottedalsoinFigurel.B.DiscussionSteamGeneratorBulkWaterBasedonamaximumfeedrateof200gpmtothesteamgeneratorandatotalsteamgeneratorliquidMlumeofapproximately12,000gallons,amaximumofonesteamgeneratorvolumeissteamedawayeachhour.Therefore,undermaximumsteamingconditions,theconcentrationfactorachievedinthebulksteamgeneratorwaterist+1wheretisthenumberofhoursofsteaming.

SolutionpH30OPl63IIEquivalentNaOHConcentrationNeutralpH~400p)rt300n200100101001000100000'l'9me,hFigure1.VariationofSteamGeneratorpHwltliSteamingat350'F(feedingLakeOntariowaterat200gpm)

ThevariationwithtimeoftheequivalentsodiumhydroxideconcentrationinthesteamgeneratorwithsteamingofemergencyLakeOntariofeedwaterthencanbefollowedonFigure1.ItisseenthatamaximumequivalentNaOHconcentrationofabout300ppmwillbereachedinthesteamgeneratorbulkwaterwhen15to20steamgeneratorvolumeswillhavebeenconvertedtosteam,i.e.,inapproximatelytwentyhours.FurtherboilingshouldthendecreasetheequivalentNaOHconcen-trationasmagnesiumand/orcalciumhydroxidesand/orcalciumsulfateprecipitatewithincreasedconcentrating.Thedecreasereachesalimit(atabout20,000steamgeneratorvolumesconvertedtosteam,i.e.,in20,000hours)whensodiumandcalciumchloridesstarttoprecipitatealso.Thislimitisestimatedatabout100ppmequivalentNaOHforLakeOntariowatercompositionasspecifiedinTable1andwiththeassumptionsalreadystated.Theassumptionsseemreasonableand;atanyrate,canbetestedexperimentallywithasmallautoclavefromwhichknownamountsofLakeOntariowaterwouldbeboiledawayat350'Fatconstantliquidlevelintheautoclave.CrevicesTheestimatedequivalentNaOHsolutionconcentrationinsteamgeneratorcreviceswilldependupontherelativedegreeofcrevicesolutionconcentrationabovethebulkwater.Intubetotubesupportplatecrevices,theremaybeadistributionofrelativeconcentrationfactorsofunityandhigher.Thechemistryinacrevicewouldleadthatofthebulkinthesensethatthechemistryofaspecificcrevicewouldtravelthesamecurve(Figure1)asthebulkbutwouldbeatapointonthecurvesomewhataheadof'hebulk.Sincesthecausticity,ofLakeOntariowaterisnotastrongfunctionofconcentration,thisdoesnotposeaproblem.Indeeditisexpectedinthiscasethatafterashortperiodofsteaming,thecrevicechemistrywillbe'essbasicthanthatofthebulk.CoolinWaterComositionTheNWTchemistrymodelingworkdiscussedhereinisbasedonthechemicalcompositionofLakeOntariowatersuamarizedinTable1assuppliedbyRGE.

Itispossiblethatseasonalchangesinthecharacteristics'fthelakewatermayresultfromtheinterrelationbetweensourceriverflowrates,industrialpollutionand/oracidrain.NMThasnorelevantdatatoassesssucheffects-ItmaybedesirablethatanalysesmadeofLakeOntariowaterduringdifferentseasonsandundervariousconditionsbefedintotheNMTchemistrymodel.InthismannerthesafetyoffeedingLakeOntariowater,overtherangeoflikelychemicalcompositions,canbeverified.

POTENTIALFORSCC~A.CorrosionThemostaggressivesolutionexpectedbasedonthemodelingworkis300ppmNaOH,withslOppm02(see.below)at350'F.Althoughlaboratorydataregardingtheseexactconditionsarenotavailable,dataareavailablewhichcanbeextrapolatedtoassessthemaximumcorrosionratesexpectedforagivenrangeofconditions.vanRooyenandKendig~citeWestinghousedataindicatingthatU-bendsofAlloy600indeaerated10NaOHcrackafterseveralmonthsofexposure.Figures,2and'3summarizeWestinghousetests'hichshowthatatleast100daysofexposuretodeaerated10%NaOHat600'FisrequiredtoproduceadetectablecrackinstressedAlloy600.Figure4showsdatagatheredbvSergeandOonati.'hesecurvesareforyieldstressedCringsat660'F.ExtrapolatingthecurveformillannealedAlloy600to300ppmNaOHyieldsaminimumtimeof3500-4000hourstoinducea0.5millimetercrack.ThedatapresentedabovearefordeaeratedsystemsandareconsistentwithvanRooyen'sconclusionthatAlloy600in10%NaOHwouldnotcrackforseveralmonths.Inthepresenceofoxygen,thesusceptibilityofAlloy600toSCCmaybeincreased.Figure5showsstresscorrosionbehaviorin600'Fhighpuritywatercontainingvarying.amountsofoxygeninthegas'haseabovethewaterandadjustedtopH10atstartupwithammonia.Astheoxygencontentofthegasphaseincreased,thepercentofthespecimensattackedandextentof'theattackincreased.AsnotedinFigure5theaveragelifeinthe18-weektestvariedfromnocrackingwith1%oxygeninthegasphase(<2ppmoxygeninthewater)to7weekswith1005oxygen-inthegasphase(<200ppmoxygeninthewater).<<IlreeandMichelsandlaterSedriks,etal.,'eportedlessthan.20Ãcrackingafter27daysforAlloy600(2commonheattreatments)inaerated,50KNaOHat570'F.7 Inseuus<<sn9.OOT.OIOQressIhtpsISsOTI$14l%11ÃIUllggUOITI.OSsiilTheresIIIAnneaiegTrasseg4404saXCO41OlOXIOXOTspasuselieslhrsiFigure2.CrackDepthasaFunctionofTime,StressLevelandMaterialConditionforIDPressurizedCapsulesExposedtoDeaerated10<NaOHat600'FL5BLOeaL3LZHeel%CM.A.T.T.gC03.OllSTOT.OZT35$.03lT34Z.04OleRsOTI31VCC&isggT-UOSylel41~emOI~~e~HeMillAnnealedThefinsllyTreated.OZBCIM.01saOCOOfspossifoTTsie1hfgl'Figure3.CrackOepthasaFunctionofExposureTimeforMillAnnealedandThermallyTreatedInconelAlloy600ExposedtoDeaeratedlOXNaOHat600F' 4000CRingsStressedtoa=YsAccordingtoASTMSTP4253000S-S-O47'r4i2000'r<J1000Alloy600HT16h1300FAlloy600MA01,00010,000100,000NaOHConcentration,ppmFigure4.ResistancetoStressCorrosionCrackingofAlloy600Mill-AnnealedorHeatTreatedat1300'FasaFunctionofDeaeratedSodiumHydroxideConcentrationat600'F~9 (VlV,IIIIIIJ'.ZI20NO.OFSPECIMENS,MII.LANN.BPERCENTCRACKED0AVI.IFEINIBWEEKTESTSIBAV.OFMAX.CRACKDEPTHS,MII00IB"0'20IB0I25BIT2ll292I550f2IOOT52~1OoIOOZ80I-I:604IZg4-')40.~,OX'<<'1~ZO1I50.IALLOY600HEATNqOXYGENINGASATSTART.('/4)8IIe4IeIe1I8l28418I8ISISI14'4I4ISISISISISIeI8IS14I4141414~14te141414278542NILNIL478256I4782564782564782562IIOOBALANCEOFGAS,HYDROGENARGON;NITROGENNITROGENAIRFigure5.StressCorrosionBehaviorinCreviceAreasinMillAnnealedlnconel600DoubleU-bendSpecimensin600'FHighPurityWaterAdjustedtopM10withAmmoniaatStartup'0 LaboratorystudiesshowthatthereisasignificanttemperaturedependenceofcausticstresscorrosioncrackingasillustratedinFigures6and7.Theseresultsareforpressurizedcapsulesexposedto105and50KNaOHatvaryingstressesattemperaturesrangingfrom650to550'F.Ascanbeseen,reducingthetemperaturebelow600'FsignificantlyextendsthetimeforSCCtooccur.ThistemperaturedependenceisfurtherillustratedinFigure8wheretemperatureisplottedversusrateconstantforboth10$and50>NaOH.B.OxygenThelakewaterfedtothegeneratorsprobablywouldbeairsaturated(approximately'0ppm02).However-,at350'FtheKO(theequilibriumratiobetweensteamphaseandliquidphase)foroxygenisslightlygreaterthan5000.Eventhoughthedynamicdistributioninpracticemaynotreachtrueequilibriumconditions,theneteffectofthehighKOvalueisthatrecriculatedsteamgeneratorcoolant'iillcontainoxygenconcentrationslowerthan10ppm.Thisrecirculatedcoolantwilldilutetheoxygenconcentrationofincomingfeedwaterwithanetoxygen'evelinthedowncomerof~lto10ppm,dependingontherecirculationratiounderthecontingencyconditions.C.ConclusionWiththesignificantlylowerconcentrationsofsodiumhydroxide(max30oppm),oxygenconcentration<10ppmandthelowertemperature(350'F)involved,thecontingencyoffeedingLakeOntariowatertotheGinnasteamgeneratorsshouldresultinnomeasureabledamagetosteamgeneratorinternals.Althoughn<<recommendedfromthestandpointofmaximizingcomponentlife,suchoperatio~forperiodsuptoseveraldaysisnotexpectedtoresu1tinanysignificantcrackingorinadeteriorationofsteamgeneratorintegrity.

NaOH50X10X575FgQ.5to5mils504030>10mils105tolpmils100.5to5mils00100020003000400pExposureTime,hrs500060007000Figure6-.CausticCrackingofNi11Annea1edA1loy600at575F(LinesdepictzonesofcrackdepthfromlOXNaOHat600'F)12

~~~V50XNaOH10X550'F1't':0<0.5mils0.5to5milsg0.5to5mils50XNaOH650F504030A'hljLa(Q20>10mils5to10mils100.5to5mils00100020003000400050006000ExposureTime,hrsFigure7.CausticCrackingofMillAnnealedA1]oy600at550Fand650F(Linesdepictzonesofcrackdepthfrom10'aOHat600F)13 200MAI-600150XIUN)Cc5ZIU100500530550570590610630Temperature,'F"igure8.IndicatedVariationinRateofSCCwithTemperature14 iI~~~~~~~~~I~~~~~~i',.rif'p~<!i.c.%I'i'4$P.COMMENTSONYANRpp>ENNDKE!iD!O'5"EppRTThereferencedreportsbas<callv;-broadsummarycoveringalargevolumeit>N4ofdataapplicableinpartto.ta::l;sssteelsandinparttoAlloy6pp.Meic>b:aregenerallyinagreementwith:hrrninesummaryconclusions,butfinditdif<<culttoapplytheirbroad-bri~ntreatmenttothespecificsofapMRhot444cH~,~shutdownwithlakewateraddedtohesteamgeneratorsat350'F.Theirdocumentg~<<f1a~'Cismisleadingforsuchanapplicationintworespects:~~~*rra'I1.CausticConcentrationv.<+eTheirstatementthat..."For.-;;";rposesofSCCpredictions,ithastobeassumedthatthetimeto.'c.:ngerouslevelsofNapH,onceimpuritieshavebeenintroduced,isshor-..:.=.,onedayorless"doesnotfullyrecognizethespecificconcen.'.:nchemistryofthecoolingwaterinvo1vednorthelowheatE':.ibleandthecutbackinsteamingrateduringaperiodofhotshutco'~>n:.hecaseoftheLakeOntariowater,forexample,themaximum.laCH=,"=.ntrationreachedis300ppm(aftersteaming~20steamgeneraoru..'s;".<ithadecreaseinconcentrationthereafter.2-TemperatureAllofthetestworkreferencedin-;hereferencedreport'asperformedinthetemperaturerangeof550to=.G=F-Withthesignificanttemperaturedependenceofcaustic-SCCasshownabove,theconcernat350'Fismanytimeslessthanisindicatedlcmthedataquotedbytheauthors.rHasedontheabovethreeconsiderations,itisourassessmentthatthegeneralizedtimelimitof36hoursin=hereport'snotdirectlyapplicabletotheGinnasteamgeneratorssteami"qt350'FwhilefedbyLakepntariowater.15

.REFERENCES1.Harhay,A.,RochesterGasInElectric,PersonalCommunication,Februaryll,.1981.2.3.4.5.6.7.9.10.Leibovitz,J.,andSawochka,S.G.,"ModelingtheEffectsofCondenserInleakageonPWRChemistry",presentedat41stAnnualInternationalMaterConference,Pittsburgh,Pennsylvania,October1980.Leibovitz,J.andSawochka,S.G.,"ModelingofCoolingWaterInleakageEffectsinPWRSteamGenerators,TopicalReport,ResearchProject404-1",ElectricPowerResearchInstitute,May1980,tobepublished.Mesmer,R.E.,Baes,C.F.,Jr.,andSwekton,F.M.,"BoricAcidEquilibriaandpHinPWRCoolarrts',Proceedingsof'the32ndInternationalWaterCon-ference,Pittsburgh,Pt.nnsylvania,November1971,pp.55-65.vanRooyen,D.,andKeadig,M.W.,"ImpureWaterinSteamGeneratorsandIsolationGenerators",BrookhavenNationalLaboratory,June1980(Draft-BNL-NUREG-28147).Airey,G.P.,"EffectofProcessing'lariablesontheCausticStressCorrosionResistanceofInconelAlloy600",presentedatNACEMeeting%March1979(PaperNumber101).Berge,Ph.andDonati,J.R.,"MaterialsRequirementsforSteamGeneratorTubing",=presentedatInternationalConferenceonMaterialsPerformanceinNuclearSteamGenerators,St.Petersburg,Florida,October1980.Copson,H.R.andEconomy,G.,"EffectofSomeEnvironmentalConditionsonStressCorrosionBehaviorofNi-Cr-FeAlloysinPressurizedWater'Corrosion,24,No.3,pp.55-65(March1968).McIlree,A.R.andMichels,H.T.,"StressCorrosionBehaviorof'Fe-Cr>>andOtherAlloysinHighTemperatureCausticSolutions",.Corrosion.33No.2,pp.60-67(February1977).Sedriks,A.J.,etal.,"InconelAlloy690-ANewCorrosionResistantMaterial","CorrosionEngineering(Japan),28,No.2,pp.82-95(1979}.4Bursteln,S,WEPCO,ltrtoH.R.Denton,NRC,dtdNovember23,1979,withattachments.16 If"'AgeI~Ig

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