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{{#Wiki_filter:i( | {{#Wiki_filter: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.................................................. | |||
~I~P~+ | ==2.0 COLOADDEFINITION== | ||
~i' | CONSERVATISMS............................ | ||
~I~1JI1g,,1I | 2.1FSTFCONSERVATI SMS2.1.1FSTFENDCAPS................................ | ||
~rII | 2.1.2FSTFSTRUCTURAL DAMPING...................... | ||
]tI~i4VjW | 2.2LDRCONSERVATISMS...................................... | ||
~I4k, | 2.2.1HARMONICCOMPONENT AMPLIFICATION............. | ||
,2~gp'f | 2.2.2SUMMINGOFHARMONICCOMPONENTS............... | ||
~jlV~Aall~ | |||
==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== | ==28.0REFERENCES== | ||
1. | |||
~Q~f':trl<~0 | 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== | ==28.0REFERENCES== | ||
(Cont'd)9.G.E. | |||
(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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| Issue date: | 11/19/1992 |
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Text
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: