ML18038A726

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Technical Response to SE by NRR Related to Proposed Deferment of Torus Mods, Nmp,Nmpns,Unit 1 Docket 50-220
ML18038A726
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Site: Nine Mile Point Constellation icon.png
Issue date: 11/19/1992
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i(TELEDYNEENGINEERING SERVICESADNISIONOFTELEDYNEBROWNENGINEERING 10ForbesRoadWoburn,Massachusetts 01801-2103 617-932-9000 FAX617-932-9970 TECHNICAL RESPONSETOSAFETYEVALUATION BYTHEOFFICEOFNUCLEARREACTORREGULATION RELATEDTOPROPOSEDDEFERMENT OFTORUSNODIFICATIONS NIAGARANOHAWKPOWERCORPORATION NINENILEPOINTNUCLEARSTATIONUNIT1DOCKETNO.50-220NOVENBER19,1992cy211g00182 921123PDRADQCK05000220PDR I

TECHNICAL RESPONSETODOCKETNO.50-220NOVEMBER19,1992TABLEOFCONTENSUMMARYi~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~o~~~~o~~~~~~~S1.0BACKGROUND..................................................

2.0 COLOADDEFINITION

CONSERVATISMS............................

2.1FSTFCONSERVATI SMS2.1.1FSTFENDCAPS................................

2.1.2FSTFSTRUCTURAL DAMPING......................

2.2LDRCONSERVATISMS......................................

2.2.1HARMONICCOMPONENT AMPLIFICATION.............

2.2.2SUMMINGOFHARMONICCOMPONENTS...............

3.0 TESCOLOADREDUCTION

-STRUCTURAL MODEL/SHELL ANALYSIS.....

4.0 ADDITIONAL

CONSERVATISMS....................................

5.0 APPLICABILITY

OFTHECONCLUSIONS PROVIDEDINTHEREVIEWOFTHEVALIDITYOFRANDOMPHASINGRULESASAPPLIEDTOCOTORUSLOADS..........

6.0NMP-1TORUSSHELLCMTR'S7.0RELEVANCE TOSAFETY..8.0REFERENCE...................................................

~Pae121820236TELEDYNEENGINEERING SERVICESADIVISIONOFTELEDYNEBROWNENGINEERING PI0 TECHNICAL RESPONSETODOCKETNO.50-220NOVEMBER19,1992SUMMARYTheNRCSafetyEvaluation Report(SER)discusses twomethodsofobtaining reliefintheevaluation forcondensation oscillation (CO)loads.Thefirstmethodistocombinethe31stressharmonics bytakingtheabsolutesumofthe4peakresponses andaddingtothisthesquarerootofthesumofthesquares(SRSS)oftheremaining 27harmonics.

Thismethodhasbeenpreviously acceptedbytheNRC.Thesecondmethodistoincorporate theanalytically determined COpressurereduction factorspresented inNiagaraMohawkPowerCorporation's recent,andsubjectsubmittal, reference 1.TheSERadvisesthatthereviewtheyhavedonesofarsupportsthepositionthatoneortheotherofthetwoapproaches maybeused,butnotboth.Thatis,ifcreditistakenfortherecentlydeveloped COpressurereduction, thenall31stressharmonics mustbecombinedbyabsolutesummation, ratherthanusingtherandomphasingrulespreviously approvedfortheMarkITorusProgram.TheCOpressurereduction represents newandadditional reliefanditsuseshouldnotprohibitusingthealreadyestablished reliefgainedfromtherandomphasingofthestressharmonics sincethetwoanalysesareindependent ofeachother.Theworkpresented inreference 1usestheContinuum

Dynamics, Inc.COpressurereduction resultsandcombinesthe31stressharmonics byabsolutesummingthe4peaksandaddingtothistheSRSSoftheremaining 27harmonics.

TheCOpressurereductionworkreducestheCOstressesbyapproximately 17%and36%fortheeightandfourdowncomer bays,respectively.

Absolutesummingthe4peakstressharmonics andaddingtothistheSRSSoftheremaining 27stressharmonics resultsinanestimated 33%lowerstressthanabsolutesummingalltheindividual harmonics.

Conversely ATELEDYNEENGINEERING SERVICESADIVISIONOFTELEDYNEBROWNENGINEERING e"4d',f TECHNICAL RESPONSETODOCKETNO.50-220NOVEMBER19,1992stated,absolutesummingalltheindividual stressharmonics overpredictsmeasuredstressesbyabout50%.Themethodofcombining thestressharmonics byabsolutesummingthe4peaksandaddingtothistheSRSSoftheremaining 27stressharmonics wastheresultofextensive structural analysisdonefortheoriginaltorusprogramandwasrecognized astheappropriate waytocorrelate FullScaleTestFacility(FSTF)measuredstresseswithFSTFanalytically predicted stresses.

Thismethodwasavailable forallplantstouse,notjustNineMilePointUnit1(NMP-1),anditisstillvalid.TheCOpressurereduction accountsfortheendcapeffectoftheFSTFinmakingitappearthatallbayshaveeightdowncomers andthehydrodynamics ineachbayareinphase.Thisisadifferent, andindependent, phenomenon thantheunderlying basistothemethodofcombining stressharmonics discussed inthepreceding paragraph.

TheBrookhaven attachment totheSERagreesthattheendcapeffectisanFSTFconservatism.

Theattachment doesnotquantifytheconservatism.

NRC-acceptance of-thereduced-CO.loading addressed hereingains-NMP-1areliefof573psiintheeightdowncomer bays,and1565psiinthefourdowncomer bays.Toseethatthisstressreduction isnominal,thesevaluesaretobecomparedtoatotalcombinedstressfromallsourcesontheorderof16,025psi.ATELEDYNEENGINEERING SERVICESADIVISIONOFTELEDYNEBROWNENGINEERING C

I\

TECHNICAL RESPONSETODOCKETNO.50-220NOVEMBER19,19921.0BACKGROUND TheMarkIProgramGeneralElectric(GE)determined themagnitude oftheCondensation Oscillation (CO)loadingbasedonthetestresultsfromtheFullScaleTestFacility(FSTF).TheFSTFfacilitywasonebaywithendcapstocontainthefluid,andasaresultofthecompromises intestfacilitydesign,theseendcapscausedconservative COshellpressures tobemeasured.

TheCOloaddefinition, basedonthesemeasuredpressures, wasconservative ontheorderof15to30percentandthiswasrecognized atthattime.TheMarkIOwners'roup determined itwouldnotbecosteffective tofundtheanalysisanddocumentation effortnecessary toachievefurtherreduction intheCOloaddefinition sincemostoftheMarkIplantshadadequatemarginonCodestressallowables fortheCOfrequency domaineventcombination loading.However,theNineMilePointUnit1(NHP-1)torushasathinshell(0.460in.)comparedwithmostofHarkIplants,andasaresult,thepostulated eventcombination whichincludesDesignBreak/Accident (DBA)pressureandCO(eventcombination 20)controlsthemarginontorusshellthickness.

TeledyneEngineering Services(TES)andNiagaraMohawkPowerCorporation (NHPC)recognized thisproblemasbeingcriticalearlyintheHarkIprogram,andjointlytookthenecessary stepstomitigateloadsfromthiseventcombination.

First,TESrefinedtheTorusAnalysisforDBApressureandCOincluding thepostprocessing ofresults.Then,TESandNMPCinitiated aseriesofthinshellmeetingsatGEforNHP-1andOysterCreek.Thesemeetingsidentified areasofconservatism intheloaddefinition tobefurtherexploredbyGE.The,reduction inNHP-1DBApressureresulting fromthesemeetingswasessential tothesuccessful compliance ofNMP-1totheHarkIProgramStructural Acceptance CriteriafortheCOeventcombination.

TheDBApressure, ratherthantheCOloadingconservatisms, wereaddressed basedoncostandtimeconsiderations.

ATELEDYNEENGINEERING SERVICESADIVISIONOFTELEDYNEBROWNENGINEERING

~I~P~+ TECHNICAL RESPONSETODOCKETNO.50-220NOVEMBER19,19922.0COLOADDEFINITION CONSERVATISMS TheloadsonwhichtheTESstructural analysisisbasedarepresented primarily inG.E.ReportNED0-21888, MarkIContainment ProgramLoadDefinition Report(LDR),datedNovember1981(Reference 3).Theseloadsweredeveloped fromtheFSTFduringtheHarkIProgramandhaveinherentconservatisms.

2.1FSTFCONSERVATISHS Therearetwomajorconservatisms inherenttothegeometryoftheFSTF,theyaretheFSTFbayendcapsandthestructural dampingassociated withthelowlevelofstressintheFSTFshell.2.1.1FSTFENDCAPSIn1979,Continuum

Dynamics, Inc.(CDI)wasaskedbytheMarkIownersgroup,throughG.E.,toassesstheconservatism intheCondensation Oscillation torusloadsmeasuredduringtheFSTFblowdowntests.Thiseffortconfirmed generally acceptedconservatism inthetestswithregardtotestinitialcondition thermodynamics, andidentified asignificant conservatism whichwasnotidentified duringtestdesign.Thisconservatism wasintroduced bythegeometryofthetestfacility, one-sixteenth sectorwhichisequivalently a22-1/2'egment oftheMarkIPressureSuppression PoolTorus.Thetestfacility, althoughfull-scale incrosssection,attempted tosimulateatfull-scale thecondensation phenomenon inonebayonly.Endcapswererequiredtocontainthepoolwaterandtheairspaceabovethepoolinthebay.Theanalysis, whichanalyzesthehydrodynamic consequences oftheseendcaps,waspresented totheHarkIownersin1980.Toexpeditecompletion ofthisissue,theMarkIownersdecidednottopursuereducingthisconservatism atthattime.Thisworkisrevisited forthiseffortanddeveloped specifically forNineMilePointUnitl.ATELEDYNEENGINEERING SERVICESADIVISIONOFTELEDYNEBROWNENGINEERING P0l>> TECHNICAL RESPONSETODOCKETNO.50-220NOVEMBER19,1992ThejointTESandCDIeffortpresented inReferences 1810andsummarized hereinconsistsofananalytical reduction intheHarkITorusProgramCondensation Oscillation LoadDefinition.

Theanalysisshowsthattheeightdowncomer bayshavebayaveragedCOloadswhichareconservative byatleast19%atfrequencies otherthan5-6Hzandforfourdowncomer bays,thebayaveragedCOloadsareconservative byatleast38%atfrequencies otherthan5-6Hz.Theloadconservatisms inthe5-6Hzfrequency bandare6%and28%fortheeightandfourdowncomer bays,respectively.

Takingallfrequency bands(0to31Hz)intoaccountresultsinanetCOloaddefinition conservatism of17.1%and36.1%fortheeightdowncomer (non-vent) andfourdowncomer (vent)bays,respectively.

2.1.2FSTFSTRUCTURAL DAMPINGDampingequalto2percentwasusedintheevaluations performed todevelopthephasingrules.Theassumption of2percentdamping,whichisappropriate fordesignresponses fromcombinedloadsnearone-halfyieldstress,maybetoohighforthelowlevelFSTFresponse.

Ifthedampingusedwereonly1.5percent,the-harmonic, responseamplitudes usedtodevelopthephasingruleswouldbesignificantly largersuchthatthecombinedcalculated responseusingtheabsolutesumofthe4peakresponses andaddingtothistheSRSSoftheremainder, wouldbeconservative comparedtothemeasuredresponse.

Inotherwords,usingtheabsolutesumoflessthanthe4peakresponses, perhapsthe3peakresponses, plustheSRSSoftheremainder, mayhaveboundedthemeasuredresponse.

Inourjudgement, dampingontheorderof1.5percentwouldbemoreappropriate forFSTFresponselevelsthan2percent.Itmustbeemphasized thatdampingof2percentismoreappropriate fordesignanalysesinwhichstresslevelsofone-halfyieldareallowable.

O'TELEDYNE ENGINEERING SERVICESADIVISIONOFTELEDYNEBROWNENGINEERING J~I1

~i'ECHNICAL RESPONSETODOCKETNO.50-220NOVEMBER19,19922.2LDRCONSERVATISMS Therearetwoconservatisms associated withthedevelopment oftheLDR,G.E.ReportNEDO-21888 (Reference 3).Thefirstconservatism isrelatedtotheamplification oftheindividual harmoniccomponents beforecombining thecomponents andthesecondconservatism isrelatedtothemethodusedtocombineorsumtheindividual harmonicstresscomponents.

2.2.1HARMONICCOMPONENT AMPLIFICATION ForFSTFtheresponseamplification factorsateach0.914Hzfrequency intervalwereusedinlieuoftheresponseamplification factorsatthestructural naturalfrequencies ineach1-Hzwindow(References 4,758).Thephasingrulesweredeveloped withthisreducedresponse.

Suchanapproachdoesnotintroduce theconservatism inresponsecalculation whichisobtainedwhenaccounting fortheresponseamplification factorsatthestructural naturalfrequencies ineach1-Hzwindow.Nocreditisgivenforthelatterapproach.

2.2.2SUMMINGOFHARMONICCOMPONENTS TheLDR(Reference 3)statesthatthecombination of'individual harmonicstresscomponents shallbesummed.Threeacceptable methodsareavailable:

1.Absolutesumofallharmoniccomponents.

2.Absolutesumofthe3highestpeaksaddedtotheSRSSoftheremaining components andapplya1.15factor.3.Absolutesumofthe4highestpeaksaddedtotheSRSSoftheremaining components, providedthereportedshellstressesarenotwithinafewpercentoftheallowables.

iTELEDYNEENGINEERING SERVICESADIVISIONOFTELEDYNEBROWNENGINEERING

~I~1JI1g,,1I TECHNICAL RESPONSETODOCKETNO.50-220NOVEHBER19,1992Theconservatisms associated withthesemethodsarebasedontheboundingofthemeasuredFSTFtestshellstressresults(TestNo'sH-8,H-llBandH-12).Hethods1and2boundallthreetests,whilemethod3fallsjustshortofboundingtestH-lR.IITELEDYNEENGINEERING SERVICESADIVISIONOFTELEDYNEBROWNENGINEERING

~rII TECHNICAL RESPONSETODOCKETNO.50-220NOVEMBER19,19923.0TESCOLOADREDUCTION

-STRUCTURAL MODELSHELLANALYSISOscillating loadsonthesubmerged portionofthetorusshellduringtheCOphenomenon arecausedbyperiodicoscillations superimposed ontheprevailing localstaticpressures.

PlantuniqueloadsarederivedfromFSTFdata.FlexiblewallloadsweremeasureddirectlyintheFSTFwhichisprototypical ofMarkIplantconfigurations withtheexception oftherigidendcaps.Pressuremeasurements obtainedfromvariouslocations onthetorusshellshowthatthelongitudinal pressureoscillation amplitude distribution alongthetorusbottomcenterlineisessentially uniformfortheFSTF.Specification ofabaselinerigidwallloadisgivenaspressureoscillation amplitude asafunctionoffrequency.

ThisloadhasbeenderivedfromthemeasuredFSTFflexiblewallloadbyanalysiswithacoupledfluid-structural dynamicmodeloftheFSTFtorus.Thederivation ofthebaselinerigidwallloadisdescribed below:a.Afiniteelementcoupledfluid-structural dynamicmodeloftheFSTFtoruswasexcitedatvaryingfrequencies withaunitamplitude pressuresourceattheventexits.Thetorusshellpressureamplitudes relativetothesourcepressure(amplification factors)weredetermined asafunctionoffrequency.

b.Usingtheserelativeamplitudes (amplification factors),

theFSTFventexitsourcepressures werederivedfromthemeasuredtorusshellpressures atthevariousfrequencies.

c.ThebaselinerigidwallloadwasderivedfromthecomputedFSTFventexitsourcepressures byhydrodynamic analysis.

IIITELEDYNEENGINEERING SERVICESADIVISIONOFTELEDYNEBROWNENGINEERING 1~I4,l TECHNICAL RESPONSETODOCKETNO.50-220NOVEMBER19,1992TheCOshellloadisspecified asadistribution ofharmonicpressureamplitudes in1Hzbands(Reference 3).Theanalysisforthisloadwasperformed byconsidering theeffectofunitloadsateachloadfrequency (harmonic analysis) andthenscalingandcombining theindividual frequency effectstodetermine totalstressatthecriticalelement.Thethreevariations intheCOspectrum(Reference 3)wereevaluated byrescaling theresultsoftheunitloadanalysis.

100%ofwatermasswasusedforallCOanalysis.

Thereduction factorspresented inTable1ofReference 10wereappliedtotheindividual harmonicpressures.

Thecombination ofindividual harmonicstressesintototalelementstresswasdonebyconsidering frequency contributions at31Hzandbelow.Theactualcombination wasdonebyaddingtheabsolutevalueofthefourhighestharmoniccontributors totheSRSScombination oftheothersforshellstress.Thiscombination methodanduseofthe31Hzcutoffaretheresultofextensive structural evaluation offullscaletestdata,whichisreportedanddiscussed inReferences 4and7.Including thefrequency contribution outto50HzwouldincreasetheCOstressbyabout20psi,orlessthan1/2%.Themethodofcombining thestressharmonics bytheabsolutesumofthe4peaksplustheSRSSoftheremainder wastheresultofextensive structural analysisdonefortheoriginaltorusprogramandwasrecognized astheappropriate waytocorrelate FSTFmeasuredstresseswithFSTFanalytically predicted stressesusingtheloaddefinition.

Touseabsolutesumofallthecomponents wouldbetoignorethephasingbetweenfrequency dependent pressurecomponents andbetweenfrequency dependent structural responses, andtoassumephasingbetweentheharmoniccomponents toproducethehighestpossiblestressresponse.

Themethodofcombining thestressharmonics bytheabsolutesumofthe4peaksplustheSRSSoftheremainder wasavailable forallplantstouse,notjustNMP-1,andtodayremainsvalid.ATELEDYNEENGINEERING SERVICESADIVISIONOFTELEDYNEBROWNENGINEERING l~'I,,~)I TECHNICAL RESPONSETODOCKETNO.50-220NOVENBER19,1992Thepresentanalysis(References 1510)investigates theconservatism ofthehydrodynamic torusCOloaddefinition derivedfromdatatakenintheHarkIFSTF.ItisshownthatduringCO,thecondensation eventsatthedowncomer exitsare,asafunctionoffrequency, randominphaseformostharmoniccomponents.

Asaconsequence ofthisobservation, andthegeometrical constraints builtintotheFSTF,theCOloadsdefinition appliedtoNHP-Iisconservative fortworeasons.~Alternate downcomer baysinNHP-Ihavefour-eight-four-eight, etc.,downcomers perbay.TheFSTFfacility, byconstruction, assumesthatallbayshaveeightdowncomers perbay.TheFSTFmodeleda22I/2'ector ofaprototypical HarkIsuppression chamber.Thewaterwascontained inthesectorbytwoveryrigidendcapswhichwouldnotexistinafullsuppression chamber.Theseendcapshydrodynamically actasmirrors.Thisresultsinameasuredload,asifallbaysinafulltorushadcondensation phenomenon identical inphaseandamplitude, totheinstrumented FSTFbay.TheanalysisshowsthatforNHP-I:~Eightdowncomer bayshavebayaveragedCOloadswhichareconservative byatleast19%atfrequencies otherthan5-6Hz.~Fourdowncomer bayshavebayaveragedCOloadswhichareconservative byatleast38%atfrequencies otherthan5-6Hz.Thepresentwork(Reference 1)accountsforboththerandomphasingofthestressharmonics andthereduction inFSTFmeasuredpressures, twoindependent phenomena.

ATELEDYNEENGINEERING SERVICESADIVISIONOFTELEDYNEBROWNENGINEERING rll~A v,TECHNICAL RESPONSETODOCKETNO.50-220NOVEMBER19,1992Inclusion ofthereducedCOloadingaddressed hereingainsNHP-Iareliefof573psiintheeightdowncomer bays,and1565psiinthefourdowncomer bays.Thesevaluesaretobecomparedtoatotalcombinedstressfromallsourcesontheorderof16,025psi.TheCOloadreduction accountsfortheendcapeffectoftheFSTFinmakingitappearthatallbayshaveeightdowncomers andthehydrodynamics ineachbayisinphasewithadjoining bays.IntheBrookhaven attachment totheSER(Reference 15)itisstatedthattheendcapsintroduce anFSTFconservatism.

made:Onpage3oftheBrookhaven attachment, thefollowing pointsareTheFSTFdatasupportthenotionthattheCOprocessisrandomovermostofthefrequency spectrumconsidered intheloadmethods.Becauseofthegeometric differences, particularly the4-8-4downcomer arrangement, thepressureloadsduringCOblowdownwilltendtobegreaterintheFSTFrelativetotheNHPtorusforthesamehydrodynamic flowconditions.

~Theprocedure usedtoquantifytheseeffectsrepresents astraightforwardapplication ofaconventional hydrodynamic method.Theresultsarereasonable andprobablyconservative becauseofthehighsoundspeedusedinthenumerics.

Wealsoconsidertheassumption thatacorrelation existsbetweenbaystobeasignificant conservatism.

ATELEDYNEENGINEERING SERVICESADIVISIONOFTELEDYNEBROWNENGINEERING 0'i~ TECHNICAL RESPONSETODOCKETNO.50-220NOVEMBER19,1992Theattachment itselfdoesnotquantifytheseconservatisms.

However,GeorgeBienkowski's reviewoftheRandomPhasingRules,datedAugust25,1983(Reference 14),alsoincludessomequantification oftheseeffects.Thisisdiscussed inSection5.0herein.IIITELEDYNEENGINEERING SERVICESADIVISIONOFTELEDYNEBROWNENGINEERING It.JI TECHNICAL RESPONSETODOCKETNO.50-220NOVEMBER19,19924.0ADDITIONAL CONSERVATISHS Thefollowing isadelineation ofadditional conservatisms forwhichnocredithasbeentaken.1.Uniformcorrosion oftheshellwouldcausethefrequencies todropandtheresponsetoCOloadtodecrease.

Ifthefrequencies drop1Hz,thenitisestimated thatNMP-1wouldgainabout600psireliefinshellstress.2.Theanalysishasbeenperformed using2%damping.Itisestimated thatincreasing thedampingto4%,toaccountforwater/structure damping,wouldgainNHP-1morethan900psirelief.Even4%dampingmaybelowforathinshelledwaterfilledstructure.

3.Thehighsoundspeedusedinthedetermination oftheCOloadreduction factorsisconservative asisshowninReference 10.4.Curvature effectsofthetorus.5.TheASHECodeallowsauniform10%reduction inwallthickness forClassMCComponents, 1990Addenda,SectionXI,Paragraph IWE-3519.3.

Thisisthesameasallowinga10%increaseinthematerialallowables.

6.TheASMECode,SectionIII,Paragraph Nf-3213.10,permitsuptoI/16inchlocalcorrosion asisexplained inTESTechnical ReportTR-6801-2 (Reference ll).7.Class1allowables forthismaterialaregreaterthanClassHCallowables by21%,Sm=20ksiforClass1vs.Sm=16.5ksiforClassHC.HTELEDYNEENGINEERING SERVICESADIVISIONOFTELEDYNEBROWNENGINEERING

]tI~i4VjW TECHNICAL RESPONSETODOCKETNO.50-220NOVEHBER19$19928.Certified HaterialTestReports(CHTR's)fortheNHP-1shellmaterialindicatehigherallowables thanthoseusedintheHarkIProgramAnalysis, 17.6ksivs.16.5ksi(seeSection6.0).Ifitbecomesnecessary tousetheCHTR's,hardnesstestscouldbeperformed onthetorusshelltoincreaseconfidence inthematerialCHTR's.9.Thereisinherentconservatism inthefactorofsafety(FS)associated withthecode,FS=1/(1.lxl/4)=3.64onultimatematerialstrength.

ItTELEDYNEENGINEERING SERVICESADIVISIONOFTELEDYNEBROWNENGINEERING

~I4k, TECHNICAL RESPONSETODOCKETNO.50-220NOVEMBER19,19925.0APPLICABILITY OFTHECONCLUSIONS PROVIDEDINTHEREVIEWOFTHEVALIDIYOFRANDOMPHASINGRULESASAPPLIEDTOCOTORUSLOADSGeorgeBienkowski issuedtheresultsofhisreviewoftheValidityofRandomPhasingRulesasAppliedtoCOTorusLoads,onAugust25,1983(Reference 14).Thereviewconcluded thefollowing:

l.A/E'scouldeliminate the1.15responsefactoronshellstressesiftheyuse4harmonics summedabsolutely addedtotheremaining summedSRSS(inlieuof1.15factoron3harmonics summedabsolutely addedtotheremaining summedSRSS),providedthereportedshellstressesarenotwithinafewpercentoftheallowables, otherwise theissueshouldberevisited.

Theadditionof1harmonic, tobesummedabsolutely, providesonlyabouta10%increaseintheresponses ratherthanthe15%neededtoboundtheFSTFmeasurements.

2.A/E'scouldneglecttheharmoniccomponents above30Hertzforstructures withsimilarnaturalfrequency contenttotheFSTForOysterCreekifspecificjustification intheformoftorusresponsefrequency characteristic ispresented.

3.A/E'scoulduseanyvariation thatproducesatleastashigharatioofresponsetothatproduced, byabsolutesumasthehighestobservedintheFSTFandOysterCreekanalyses(63%).TherefinedshellanalysisoftheNMP-1torusshell,performed byTES,usingthereducedCOloaddefinition includesthefollowing:

1.TheCOloadreduction resulting fromtheFSTFendcaps,17.1%and36.1%fornon-ventandventbays,respectively.

ATELEDYNEENGINEERING SERVICESADIVISIONOFTELEDYNEBROWNENGINEERING v.r,jl4 TECHNICAL RESPONSETODOCKETNO.50-220NOVEMBER19,19922.Thecombination ofindividual harmonicstressesintototalelementstresswasdonebyconsidering frequency contributions at31Hzandbelow.Theactualcombination wasdonebyaddingtheabsolutevalueofthefourhighestharmoniccontributors totheSRSScombination oftheothersforshellstress.Thiscombination methodanduseofthe31Hzcutoffaretheresultofextensive numerical evaluation offullscaletestdata.Including thefrequency contribution outto50HzwouldincreasetheCOstressbyabout20psi,orlessthanI/2%.GeorgeBienkowski's reviewoftheRandomPhasingRulesalsoaddressed the,impactoftheendcapsonproducing conservatively measuredCOloads.Thisdiscussion beginsatthebottomofpage3ofthereview.Here,thereviewreferstoanunreferenced communication inReportsSMA12101.04-R002D (Reference 7)andSMA12101.04-R003D (Reference 8),fromDr.AlanBilanin,thatthepresenceofthebulkheads introduces afactorofconservatism ofatleast1.33tothemeasuredCOloadingandresponses fromwhichtheLDRamplitudes

-werederived.Thisisseparatefromthephasingrulesgoverning thesummation ofstressharmonics.

Inaddition, an"Appendix A"ismentioned whereinthiseffectisexamined.

This"Appendix A"isassumedtobeanappendixtoGeorgeBienkowski's reviewandithasnotbeenreviewedbyTESorCDI.ItisstatedthattheAppendixconcludes thatforfrequencies thatarenotcorrelated betweenbays,theFSTFshouldproduce32%to35%higherloadsthanwouldexistinarealfacilityandthatonlythefundamental frequency near6Hzshowsanycorrelation betweendowncomers.

Thereviewfurtherstatesthatifoneassumescorrelation betweenbaysatthatfrequency andrandomphasing(thisisnottherandomphasingofresponsestressharmonics) atallotherfrequencies, theoverallconservatism forIITELEDYNEENGlNEERlNG SERVICESADIVISIONOFTELEDYNEBROWNENGINEERING 1~ck TECHNICAL RESPONSETODOCKETNO.50-220NOVEMBER19,1992theaveragepressure~abeaslowas17%(notethereviewsays"may"),whileattheresponseleveltheFSTFconservatism willrangefrom18%forhoopstressto38%fortheaxialstress.Theseindependent Brookhaven generated resultsarenotunlikethosethatNNPCiscurrently presenting.

RobertKennedy,inhisreportSMA12101.04-R003D (Reference 8),usesthisadditional 33%conservatism, advancedbyDr.AlanBilanin,toaccountfortheuncertainty ofusingonlythethreepeakresponses fromFSTFtestsH-8,H-llBandM-12.Ontheotherhand,GeorgeBienkowski arguesthatthisuncertainty estimateisprobablyexcessively conservative andthat7%ratherthan33%uncertainty wouldprovideahighconfidence levelofnon-exceedance.

UsingtheabovenumbersfromGeorgeBienkowski's work,wehaveasaminimumthatthemeasuredstressesareconservative byatleast:(1-[(1-.18)(1+.07)])100

=(1-,88)100

=12%Also,nomentionhasbeenmadeinGeorgeBienkowski's reviewregarding theeffectofthe4-8-4downcomer configuration.

ThejointTES/CDIwork(Reference 1)evaluates thiseffectaswell.Sowearelookingfor17%reliefinthe8downcomer baysandtheBrookhaven workshowsatleast12%relief.Thedifference maybeattributed tothe4downcomer baystoeithersideofthe8downcomer bay.Inaddition, the36%reduction thatwehaveevaluated forthe4downcomer baysalsoincludesthefactthatonlyhalfasmanydowncomers arepresentasareintheFSTF,aneffectnotmentioned inGeorgeBienkowski's review.ATELEDYNEENGINEERING SERVICESADIVISIONOFTELEDYNEBROWNENGINEERING

,2~gp'f TECHNICAL RESPONSETODOCKETNO.50-220NOVEMBER19,1992Theconservatisms relatedtotheendcapeffectdiscussed hereinwerenotincludedinGeorgeBienkowski's conclusions regarding thephasingrules.Oncetheendcapeffectisincluded, thereisnoreasonwhytheresulting responseshouldboundFSTFdata.Indeed,byitsverynature,itshouldnotboundFSTFdata.ATELEDYNEENGINEERING SERVICESADIVISIONOFTELEDYNEBROWNENGINEERING r1V~wg/ TECHNICAL RESPONSETODOCKETNO.50-220NOVEMBER19,19926.0NAP-ITORUSSHELLCNTR'SCertified MaterialTestReortReviewforTorusShell(Reference 11)TEShasreviewedtheTorusShellCertified HaterialTestReports(A201GrBFBX).Astatistical analysiswasperformed usingthis(large)sampledatatodetermine the.99confidence intervalestimateofthemeanyieldandultimatestrengthofthismaterial.

TheCoderequiresthattheminimumyieldandminimumultimatestrengthofthematerialbeusedtodetermine theallowable stressintensity (SgC)asfollows:SgCat70'Fisthelessorof1'15SYor1.11SUTherefore, TEShasassumedthattheminimumyieldandultimatestrengths ofthematerialareboundedbyusingtwosamplestandarddeviations fromthestatistically estimated minimummeanvalues.Basedonthecalculations usingtheabovestatedcriteria, theCodeallowable stressintensity wouldbeestimated at:SNC=17600at70'FUseofthisestimated allowable stressintensity willprovideanadditional 1100psireliefascomparedtothepresentCodeallowable of16500psiwhichwasusedduringtheHarkIContainment ProgramanalysisforATELEDYNEENGINEERING SERVICESADIVISIONOFTELEDYNEBROWNENGINEERING S',fI TECHNICAL RESPONSETODOCKETNO.50-220NOVEHBER19,1992thetorusshellmaterialforthefullrangeofanticipated eventtemperatures from70to350'F.Intermsofreliefontheshellthickness requirements, theincreased allowable willprovidejustunder1/32inchesor6/.additional margin.ATELEDYNEENGINEERING SERVICESADIVISIONOFTELEDYNEBROWNENGINEERING qXmy<~),+LC TECHNICAL RESPONSETODOCKETNO.50-220NOVEHBER19,19927.0RELEVANCE TOSAFETYWedonotviewthisissueasadversely affecting safety.Itcanberegardedastheeffortundertaken toremoveknownconservatisms throughrefinement ofthepostulated appliedCOloads.Inaddition, resolution ofCodeissuespertaining totheallowable materialstrengthandallowable nominalcorrosion, delineated inSection4.0,"Additional Conservatisms",

ifintroduced, wouldprovideforaddedmarginforthetorusshellstresses.

Also,themanyotherconservatisms discussed throughout thisresponse, ifaccounted for,wouldfurtherreducetheshellstress.TorusCorrosion Rate(>)NiagaraHohawkundertook anewcorrosion monitoring programinAugust,1989.Underthisprogram1'3'ridsonall40midbaybottomplateswereUTinspected.

HPRAssociates, Inc.ReportHPR-1152delineates theresultsofthisinspection.

Thesemeasurements didnotshowanysignificant lossduetocorrosion orpittingevenatthenormalwaterlevelregion;andtherewerenowallthickness measurements thatwouldrequireapplication ofthemethodsdescribed inTeledyneReportTR-6801-2, reference 11.HPRquantified theshellthickness loss,over20years,bycomparing themeasuredshellthickness valuestothecalculated originalplatethickness.

Thirtyfourshellplates,traceable totheoriginalmilcertifications, wereusedinthiscomparison.

Originalplatethicknesses werecalculated usingplatedimensions, weightanddensityofthesteel.Thesethicknesses werecomparedtotheUTthickness obtainedinAugust,1989,onthesame34plates.Theresultsindicated anaveragecorrosion lossof0.8milsperyear.Thisratetranslates toatotallossof32milsoraboutI/32"overtheoriginalprojected 40yearplantlife;andcomparescloselytotheratepredicted byRadiological 8ChemicalTechnology, Inc.(RCT),basedonanalysisofsludgesamplesin1979.Duetovariations in(1)Thisinformation providedbyNHPC.ATELEDYNEENGlNEERlNG SERVlCESADIVISIONOFTELEDYNEBROWNENGINEERING Vrl-k TECHNICAL RESPONSETODOCKETNO.50-220NOVENBER19,1992theoriginalplatedimensions andweights,andmeasurements, onestandarddeviation wasaddedtothe0.8milsperyear.Thisresultedinaconservative prediction of1.26milsperyearcorrosion rate.Additionally, NiagaraMohawkPowerCorporation committed toperformUTmeasurements onasixmonthbasisandprovidetheNRCwiththeresults(Ref.November22,1989,letterC.TerrytoNRC).Sincebaselineestablishment ofthenewcorrosion programof1989,six(6)six-month measurements havebeenconducted, themostrecentofwhichwerejusttakeninSeptember, 1992.Furtheranalysisandtrendingofthesemeasurements indicatethataconservative corrosion rateof1mi-l/yrincluding onestandarddeviation isamorerealistic corrosion ratethanthebaselineestimateof1.26mils/yr.Themostprobableprediction ofcorrosion rateisstill0.8mils/yr,butthelaterresultshavereducedthestandarddeviation to+0.2mils/yr.Thelatest(September, 1992)UTmeasurements, onthethinnesttorusplatesindicates theaveragethickness oftheworstplateis0.453inches.Thisthickness represents anaverageof63individual measurements (calibration adjusted) ona1'3'ridonthatworstplate.Worstcaseindividual measurements onthisorotherplateshavebeenaslowas0.445inches(calibration adjusted).

Overthenextyear,theprojected worstcaselossofthickness wouldbeonemilor0.001".Thiswouldtheoretically reducetheworstgridtoa0.452"averagethickness andtheworstindividual pointto0.444".Theaveragethickness wouldcomplywithminimumthickness allowedbyTeledyneReportTR-6801-2, reference 2,andtheoretically provideforaboutanother5yearsofoperation beforereachingthecurrentminimumthickness allowed.However,the0.444"individual pointwouldhavetobeanalyzedforcompliance toTR-6801-2 bythemethodsoutlinedtherein.Theanalysissubmitted underNHPC'sMay14,1991coverletter(Reference 1),totheNRCsupportsanyaveragethickness orindividual 6TELEDYNEENGINEERING SERVICESADIVISIONOFTELEDYNEBROWNENGINEERING TECHNICAL RESPONSETODOCKETNO.50-220NOVEMBER19i1992pointdownto0.431".Inaddition, themanyotherconservatisms discussed herein,forwhichnocredithasbeenrequested ortakenintoaccount,wouldsupportreductions inexcessofthis.Therefore, lossofthickness occurring duetoprojected corrosion overthenextyearwouldbewithinlimitsofsupporting analyses.

ATELEDYNEENGINEERING SERVICESADIVISIONOFTELEDYNEBROWNENGINEERING

~jlV~Aall~ TECHNICAL RESPONSETODOCKETNO.50-220NOVEMBER19,199

28.0REFERENCES

1.TESTechnical ReportTR-7353-1, Revision2,"NineMilePointUnit1,Reduction inHarkITorusProgramCondensation Oscillation LoadDefinition andResulting EffectonMinimumShellThickness Requirements,"

datedJanuary14,1992.2.-TESReportTR-5320-1, Rev.1,"HarkIContainment Program,Plant-Unique AnalysisReportoftheTorusSuppression ChamberforNineMilePointUnit1NuclearGenerating Station,"

datedSeptember 21,1984.3.G.E.ReportNED0-21888, Rev.2,"MarkIContainment ProgramLoadDefinition Report,"datedNovember1981.4.G.E.ReportNEDE-24840, "HarkIContainment Program-Evaluation ofHarmonicPhasingforMarkITorusShellCondensation Oscilla-tionLoads,"datedOctober1980.5.G.E.ReportNED0-24574, Rev.1,"HarkIContainment Program-Plant-Unique

.LoadDefinition

-NineMilePoint1NuclearGen-eratingPlant,"datedJuly1981.6.ASMEB&PVCode,SectionIII,Division1throughSummer1977.7.Structural Mechanics Associates ReportSHA-12101.04-R002D, "Response FactorsAppropriate forUsewithCOHarmonicResponseCombination DesignRules,"datedMarch1982.8.Structural Mechanics Associates ReportSHA-12101.04-R003D, "AStatistical BasisforLoadFactorsAppropriate fo}UsewithCOHarmonicResponseCombination DesignRules,"datedMarch1982.ATELEDYNEENGINEERING SERVICESADIVISIONOFTELEDYNEBROWNENGINEERING

~Q~f':trl<~0 TECHNICAL RESPONSETODOCKETNO.50-220NOVEMBER19,199

28.0REFERENCES

(Cont'd)9.G.E.Supplementary SupportEffort(SSE)ResponseNumber310,datedFebruary8,1982.10.Continuum DynamicsTechnical NoteNo.90-11,"Reduction ofTorusShellCondensation Oscillation Hydrodynamic LoadsforNineMilePointUnit1,"datedNovember1990.ll.TESTechnical ReportTR-6801-2, "MarkITorusShellandVentSystemThickness Requirements,"

NineMilePointUnit1NuclearStation,January29,1988,Rev.l.12.HarkIContainment Program,Structural Acceptance

Criteria, PlantUniqueAnalysisApplication Guide,NED0-24583-1, October1979.13.TESCalculation Package7353-1,Revision2,"NineNilePointUnit1,Reduction inHarkITorusProgramCondensation Oscillation LoadDefinition andResulting EffectonMinimumShellThickness Requirements,"

datedJanuary14,1992.14."ReviewoftheValidityofRandomPhasingRulesasAppliedtoCOTorusLoads,"byGeorgeBienkowski, datedAugust25,1983,Containment SystemsGroup,Department ofNuclearEnergy,Brookhaven NationalLaboratory.

15.UnitedStatesNuclearRegulatory Commission, "SafetyEvaluation bytheOfficeofNuclearReactorRegulation RelatedtoProposedDeferment ofTorusModifications, NiagaraMohawkPowerCorporation, NineMilePointNuclearStationUnit1,DocketNo.50-220,"datedAugust25,1992.IIITELEDYNEENGINEERING SERVICESADIVISIONOFTELEDYNEBROWNENGINEERING gg~g>.g4:

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