ML17309A637

Forwards Addl Info Re Response to GL 96-06,as Requested in 980414 Ltr

ML17309A637
Person / Time
Site:	Ginna
Issue date:	07/21/1998
From:	MECREDY R C ROCHESTER GAS & ELECTRIC CORP.
To:	VISSING G S NRC (Affiliation Not Assigned), NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GL-96-06, GL-96-6, TAC-M96814, NUDOCS 9807290262
Download: ML17309A637 (17)

Text

CATEGORY1REGULATiINFORMATION DISTRIBUTIO YSTEM(RIDS)I'ACCESSION NBR:9807290262 DOC.DATE:

98/07/21NOTARIZED:

YESDOCKETFACIL:50-244 RobertEmmetGinnaNuclearPlant,Unit1,Rochester G05000244AUTH.NAME'UTHORAFFILIATION MECREDY,R.C.

Rochester Gas5ElectricCorp.RECIP.NAME RECIPIENT AFFILIATION VISSING,G.S.

SUBJECT:

ForwardsaddiinforeresponsetoGL96-06,asrequested in980414ltr.CDISTRIBUTION CODE:A072DCOPIESRECEIVED:LTR ENCLSIZE:TITLE:GL96-06,"Assurance ofEquipOprblty&Contain.Integ.

duringDesignT05000244ERECIPIENT IDCODE/NAME NRR/WETZEL,B.

VISSING,G.INTERN:FILECER/DSSASCSBEXTERNAL:

NOACCOPXESLTTRENCL1111111111RECIPIENT IDCODE/NAME PD1-1PDNRR/DE/EMEB NRR/DSSA/SPLB NRCPDRCOPIESLTTRENCL111111110DUNNOTETOALL"RIDS"RECIPIENTS:

PLEASEHELPUSTOREDUCEWASTE.TOHAVEYOURNAMEORORGANIZATION REMOVEDFROMDISTRIBUTION LISTSORREDUCETHENUMBEROFCOPIESRECEIVEDBYYOUORYOURORGANIZATION, CONTACTTHEDOCUMENTCONTROLDESK(DCD)ONEXTENSION 415-2083TOTALNUMBEROFCOPIESREQUIRED:

LTTR9ENCL9

.1I ROCHESTER GASANDELECTRICCORPORATION 89EASTAVENUE, ROCHESTER, NY.14649-0001 AREACOOE716-546-2700 ROBERTC.MECREDYVicePresident NvdearOperations July21,1998U.S.NuclearRegulatory Commission DocumentControlDeskAttn:GuyS.VissingProjectDirectorate I-lWashington, D.C.20555

Subject:

ResponsetoRequestforAdditional Information (RAI)RelatedtoGenericLetter96-06(TACNo.M96814)R.E.GinnaNuclearPowerPlantDocketNo.50-244Ref.(1):LetterfromGuyS.Vissing(NRC)toRobertC.Mecredy(RG&E),

SUBJECT:

REQUESTFORADDITIONAL INFORMATION RELATEDTOGENERICLETTER96-06RESPONSEFORR.E.GINNANUCLEARPOWERPLANT(TACNO.M96814),datedApril14,1998

DearMr.Vissing:

ByReference 1,theNRCstaffrequested additional information regarding theResponsetoGenericLetter96-06fortheR.E.GinnaNuclearPowerPlant.Theattachment tothisletterprovidestherequested information.

Veryyyours,RobertC.MecredyAttachment Subscribed andsworntobeforemeonthis21stdayofJuly,1998C'.u'otaryPublicMARIEC.VII.I.ENEUVE NotaryPublic,StateofNewYoiRMonroeCountyCommission ExltiresOctober31,19m'st8072'st0262

'st8072iPDRADQCK05000244PPDR

~~

~~xc:Mr.GuyS.Vissing(MailStop1482)ProjectDirectorate I-lDivisionofReactorProjects-I/IIOfficeofNuclearReactorRegulation U.S.NuclearRegulatory Commission Washington, D.C.20555RegionalAdministrator, RegionIU.S.NuclearRegulatory Commission 475Allendale RoadKingofPrussia,PA19406U.S.NRCGinnaSeniorResidentInspector RESPONSETONRCREQUESTFORADDITIONAL INFORMATION (RAI)FORRESOLUTION OFGENERICLETTER96-06ISSUESATTHER.E.GINNANUCLEARPOWERPLANTI.Ifamethodology otherthan(orinadditionto)thatdiscussed inNUREGICR-5220,

,"Diagnosis ofCondensation-Induced Waterhammer",

wasusedinevaluating theeffectsofwaterhainmer, describethisalternate methodology indetaiLAlso,explainwhythismethodology isapplicable andgivesconservative resultsfortheGinnaplant(typically acco>nplished throughrigorousplant-speci Jtcmodeling, testing,andanalysis).

Response

Rochester GasandElectricCorporation's (RG&E's)analyseswhichwerethebasesoforiginalresponsetoGL96-06evaluated thatseverewaterhammer hasaverylowprobability ofoccuringattheSWwaterpipingupstreamanddownstream oftheContainment Recirculation FanCoolers(CRFC's)duetothepresenceofheatedwaterthatactsasabufferbetweencoldwatersectionsandsteamthatformedattheCRFC'sduringfancoastdown.

Theanalysesalsoconsidered averyconservative situation thatwhenwaterhammer doesoccuratCRFCtubesandSWpiping,usingpredictive methodssimilartoNUREG/CR-5220, thestructural integrity oftheSWpressureboundarywillnotfailinthehoopdirection whichhasthedominantstressfield.Furthermore, RG&E'spreliminary evaluation ofeffectsofthefluid/structure interaction oftheefectsofatraveling pressurepulseassociated withasteamvoidcollapsedownstream oftheCRFCshasindicated thattheSWpipingwillbeprotected fromlossofstructural integrity bytheexistingseismicpipesupportsintheSWpiping.-Thisevaluation utilizedmorerealistic valuesfortheacousticparameters thanthosepresented inNUREG/CR-5220.

Specifically, theacousticvelocityusedinEquation5.5ofNUREG/CR-5220 tocalculate thepressurepulsefromasteamvoidcollapsewasobtainedfromNUREG/CR-6519, "Screening ReactorSteam/Water PipingSystemsforWaterHammer".Additionally, thewaterslugvelocityusedinEquation5.5wasbaseduponthemaximumSWvolumetric flowassociated withtheoperation oftwoSWpumpsfollowing aLOOPcondition.

Assoonasprojectscopeandcostarefinalized byEPRI,RG&Ewillmakeafinaldecisiontoparticipate inacombinedIndustry/NEI/EPRI Collaborative Projecttodevelopatechnical basisdocumenttoaddresswaterhammer issuesofGL96-06,delineated inaJune5,1998letter(Reference 1)fromMr.DavidJ.Modeen(NEI)toMr.LedyardB.Marsh(NRC).RG&Eplanstorefinethewaterhammer analysisoftheCRFC/SWsysteminatimeframeconsistent withthecompletion ofthiscollaborative project.

RAIResponseGL'96-06'age22.Forboththewaterhanuner andtwo-phase flowanalyses, providethefollowing information:

a.Identifyanycomputercodesthatwereusedinthewaterhammer andtwo-phase floanalysesanddescribethemethodsusedtobenchmarkthecodesforthespecificloadingconditions involved(seeStandardReviewPlanSection3.9.1).Response:

Duringanalysesoftwo-phase flowissues,RG&Ehasutilizedtheresultsofacomputercode,KYPIPE,"Computer AnalysisofFlowinPipeNetworksIncluding ExtendedPeriodSimulations",

Rev.2.13whichwasdeveloped byDr.D.J.Wood,Department ofCivilEngineering, University ofKentucky.

ThiscodehasbeenverifiedandtestedperRG&EProcedure QE330(Reference 3).Duringtestsofthenewlyinstalled CRFCsA,B,C,&Din1993,KYPIPEwasutilizedtocheckflowdistributions foroneandtwoservicewater(SW)pumpoperations (Reference 4).Goodagreement betweentestandanalytical resultswereobtained.

AlthoughKYPIPEmodelsliquidsystems,additional two-phase flowresistances wereinputtocalculate theflowreductions withflashing.

Noothercomputercodeshavebeenusedintheanalysesofthoseeffects.b.Describeandjustifyallassumptions andinputparameters (including those<<sedinanycomputercodes)suchasamplification duetofluidstructure interaction, cushioning, speedofsound,forcereductions, andmeshsizes,andexplainwhythevaluesselectedgiveconservative results.Also,providejustiflcation foromittinganyeffectsthatmayberelevanttotheanalysis(e.g.,fluidstructure interaction, flowinducedvibration, erosion).

WhiletheJanuary30,submittal wasnotexpectedtobecompleteinthisregard,examplesofinformation thatiscontained intheJanuary30,submittal thathasnotbeenadequately justified include:.assumption thatthecontainment recirculation fancoolers(CRFCs)willcoastdownoveraperiodof30seconds; RAIResponseGL'96-06'age3Response:

TheCRFCfancoastdown timewasobtainedbaseduponactualcoastdown testingoftheGinnafansatambientconditions toquantifythefan/motor inertialresistance.

Thisinertialresistance wasthenusedinacomputermodeltocalculate thefan/motor coastdown underaccidentconditions.

Thecomputermodelwasverifiedbycomparing modelpredictions forfanstart-upunderambientandIntegrated LeakRateTest(ILRT)conditions toactualfanstart-uptestdatatakenduringtheseconditions.

ItshouldbenotedthattheILRTtestconditions closelymatchtheexpectedpostaccidentconditions.

Thecomputermodelcloselymatchedthisdata.Thecomputermodelpredicted afancoastdown of22seconds.RG&Echoosedtouse30secondsintheanalysesforconservatism.

applicability andvalidityofEPRIinterimanddraftreports(references 3.7and3.8oftheJanuary30,submittal;

Response

Theconclusions oftheEPRIreportsreferenced inRG&E'sJanuary30,1997submittal havebeensupported byevaluations performed byRG&EoftheCRFCsteamboilingandsteamgrowthtransient usingGinnaspecificconditions.

TheRG&Eevaluations concluded thatappreciable boilingofsteamintheCRFCswouldoccurfollowing aLOOPcondition.

Additionally, consistent withtheEPRIreports,theRG&Eevaluations concluded thattheresulting steamvoidwouldmigratetotheSWinletandoutletpiping.DuetotheUbendconfiguration oftheGinnaSWinletandoutletpipingdescribed intheJanuary30,1997submittal, thesteamgrowthwouldcausesignificant heatingofthewatercontained intheSWpipingsimilartothatdescribed bytheEPRIreports.othersectionsoftheCRFCswillresisttheeffectsofwaterhammer peakpressure;

Response

AsstatedinRG&E'sJanuary30,1997submittal, thenon-tubesectionsofthenewCRFCsweremanufactured withenhancedstructural capabilities.

TheCRFCdesignoftheplenumboxesincludestheuseofpassribsandspacerswhichareheldtogetherbymultipleboltsthatcanabsorbasubstantial amountofstrainenergy.Thisincombination withtheattenuation duetoplenumentrance/exit affectsofwaterhammer pressurepulsesgenerated intheCRFCtubesorSWpipinghasbeenevaluated tobesufficient tomaintainthestructural functionality oftheplenumboxes.

RAIResponseGL'96-06Page4theamountofsteamformedandextentofthesteaInenvelopethatisformedwithintheservicewaterpiping(i.e.,whereisthesteamlwater interface andwhatisthebasisforwatertemperature assumptions);

andResponse:

Preliminary evaluations oftheextentofthesteambubbleformedduetotheSWpumpandCRFCfancoastdown andstart-uptransients following aLOOP,havedetermined thatthesteamenvelopeonthedischarge sideoftheCRFCcouldextendintothe8"and14"SWpipingintheIntermediate Building.

Consequently, forthepreliminary fluid/structural interactions discussed inresponsetoQuestion1,RGkEevaluated theexpectedpressurepulsefromavoidcollapseinboththe8"and14"SWdischarge piping.SincethewaterslugintheSWdischarge pipingbeingdrivenbythestart-upoftheSWPumphasbeenheatedbytheCRFCs,theactualtemperature ofthewaterslugdoesnotaffectthepressurepulsegenerated bythecollapseofthesteamvoid.Thewaterslugvelocityiscontrolled bythevolumetric flowoftheSWpumpswhicharepushingthewaterslugthroughtheSWpipingandcollapsing thesteamvoidgenerated duetoboilingintheCRFCspriortotherestartoftheSWPumps.Consequently, thepreliminary evaluation ofthefluid/structural interaction discussed inQuestion1arebaseduponawaterslugvelocityintheCRFCpipingduetothestart-upoftwoSWPumpsfollowing aLOOP.waterte)nperature assumption usedforevaluation ofwaterhammer intheservicewatersystemdischarge piping.Response:

TominimizethetimetoboilingintheCRFCsandtomaximizethevolume'of thesteamvoidcreatedbyboilingintheCRFCs,alloftheRG&Eevaluations havebeenperformed withamaximumSWinlettemperature of85'F.Sinceanysteamvoidcollapseisexpectedtobelimitedbythevelocityofthewaterslugbeingdrivenbytheoperating SWPumps,theSWtemperature isexpectedtohavelittleeffectonthepressurepulsegenerated byasteamvoidcollapse.

RAIResponseGL'6-06Page5c.Provideadetaileddescription ofthe"worstcase"scenarios forwaterhaminer andtwo-phase flow,takingintoconsideration thecompleterangeofeventpossibilities, systemconfigurations, andpara>neters.

Forexample,allwaterhammer typesandwaterslugscenarios shouldbeconsidered, aswellastemperatures, pressures, flowrates,loadcombinations, andpotential component failures.

Additional examplesinclude:theeffectsofvoidfractiononflowbalanceandheattransfer; theconsequences ofsteamforInation, transport, andaccumulation; cavitation, resonance, andfatigueeffects;anderosionconsiderations.

Licensees mayflndNUREGiCR-6031, "Cavitation Guide'orControlValves,"helpfulinaddressing someaspectsofthetwo-phase flowanalysesResponse:

c.1:Itemsrelatedtowaterhammer issuesintheaboveRAIwillbedeferreduntilafterdevelopment ofthewaterhammer technical basisdocument(References 1,2).Itemsrelatedtotwo-phase flowareprovidedbelow.c.2:Two-Phase FlowIssuesTheCRFCsystemforGinnaconsistsoffourCRFCunits,eachunitincludesthemotorfan,coolingcoils,moistureseparators, highefficiency particulate airfilter,ductdistribution system,andinstrumentation andcontrol.DuringthepostaccidentperiodtwooftheCRFCunitsarerequiredfordepressurization oftheContainment (Reference 5).Thecoolingwaterrequirements ofthefourCRFCunitsaresuppliedbyaservicewater(SW)systemwhichprovidesaheatsinkforremovalofheatduringnormaloraccidentconditions.

TheSWsystemconsistsofasingleloopheadersuppliedbytwoseparate, 100%capacity, safetyrelatedpumptrains(seeAttachment 1Schematic).

EachtrainispoweredfromaseparateClass1Eelectrical busandconsistsoftwo100%capacitypumpsandassociated checkandisolation valves.Duetoredundancy considerations, theSWsystemisdesignedsuchthatoneSWpumpcansupplythecoolingwaterrequirements ofthefourCRFCunitsduringdesignbasistransients/accidents.

Eachofthetwoemergency dieselspowersaSWpumpwhichautomatically startsaspartoftheemergency RAIResponseGL'96-06Page6bus-loading sequenceonlossofnormalacpowercoincident witharequirement forengineered safetyfeaturesoperation (SIsignal).Duringpostaccidentcondition, eachofthefourCRFCunitswillprovideaminimumheatremovalcapacityof54.6MBtu/hrwithContainment condition of74.7psiaand286F(Ref.5).WealsonotethatonlytwooftheCRFCunitsarerequiredfordepressurization oftheContainment duringpostaccidentconditions.

RGB'asevaluated thefollowing "worstcase"scenarios asboundingcasesforconsideration oftwo-phase floweffectsintheCRFC/SWsystems.ScenarioNo.1:Consideration ofone100%capacitySWpump,twoavailable CRFCunits,SWinletwatertemperature of85F,andadesignfoulingfactorof0.001hr-sqft-oF/Btu (Reference 5).ThemaximumfoulinglimitsheattransfercapacityattheCRFCunits,whilethemaximuminletSWtemperature optimizes temperature distribution attheSWpipingmakingtwo-phase formation ahighpossibility duringaoneSWpumpmodeofoperation.

ScenarioNo.2:Consideration ofone100%capacitySWpump,twoavailable CRFCunits,SWinlettemperature of85F,andcompletely cleantubes,(i.e.,foulingfactorof0.000hr-sqft-F/Btu).CleantubesandaSWinlettemperature of85Foptimizes thetemperature fieldattheSWpiping,makingtwo-phase flow'formation ahighpossibility especially atoutletpipingdownstream oftheCRFCs,foraoneSWpumpoperation.

ScenarioNo.3:Consideration ofone100%capacitySWpump,fourCRFCunits,SWinlettemperature of85F,andcompletely cleantubes(i.e.,foulingfactorof0.000hr-sqft-F/Btu).ThisscenarioprovidesmoreflowpathsfortheSWflowdistribution system,andconsequently minimizes theSWpressurefieldattheinletandoutletpipingoftheCRFCunits.CleantubesandthemaximumSWtemperature optimizes thetemperature fieldattheSWsystem,especially attheCRFCoutletpiping,makingtwo-phase flowformation ahighpossibility duringaonepumpoperation.

RAIResponseGL'96-06'age7Evaluation ofthese"worstcase"scenarios aredocumented inReferences 6,7,and8.Incaseswheretwo-phase flowcanform,RGB'nvestigated theeffectsofvoidfractiononflowbalanceandheattransferconsidering theconsequence ofsteamformation, transport, andaccumulation oftwo-phase inventory.

Utilizing Reference 9,RG8cEalsoevaluated theeffectsoftwo-phase flowfieldintheerosion,cavitation, resonance, andfatigueofthepipingpressureboundary.

Theseeffectsarenegligible sincethereisnoviolentcollapseofthetwo-phase flowandthedurationisshortterm.Resultsoftheevaluation aresummarize below.1.Forscenarios 1,2Ec3two-phase flowwillnotformattheCRFCcoils.2.Forscenarios 1,2and3,twophaseflowcanoccurattheSWdischarge pipingdownstream oftheCRFCsandoutsideofContainment.

Effectsofthiscondition onflowbalanceandheattransferwerefurtherinvestigated andfoundthateachCRFCcanstillprovidetheminimumheatremovalcapacity(References 6,7,8)toperformitsdesign-basis functionasrequiredintheaccidentanalysisforGinna(Reference 13).d.Confirmthattheanalysesincludedacompletefailuremodesandeffectsanalysis(FMEA)forallcomponents (including electrical andpneumatic failures) thatcouldimpactperformance ofthecoolingwatersystemandconPrmthattheFMEAisdocumented andavailable forreview,orexplainwhyacompleteandfullydocumented FMEAwasnotperformed.

Response

Theanalysesthatwereundertaken byRG&EtorespondtotheoriginalGL96-06requirements andthecurrentRAItookintoconsideration resultsofFMEAanalysis(Reference 11)andthesingleactivefailureanalysisoftheGinnaServiceWatersystem(Reference 10).Theseanalysesarewelldocumented andareavailable forreview.

RAIResponseGL'6-06'age8e.Explainandjustifyallusesof"engineering judgment".

Response

Tolimittheextentoftheanalysesneededtobeperformed forassessing theconsequences oftwo-phase flowintheSWdischarge pipingonCRFCheatremovalcapability, RGAEusedengineering judgement toestablish boundingcasesthatwouldbeanalyzed.

Forexample,theheatremovalcapability oftheCRFCwasanalyzedforthetwoboundingCRFCfoulingconditions ofnofouling(cleanCRFCs)anddesignfouling.Theseresultsareexpectedtoenvelopetheresultsobtainedforanyotherfoulingcondition.

Consequently, baseduponthisengineering judgement, detailedtwo-phase flowanalyseswereonlyperformed forthesetwocases.Enginering judgement wasalsousedtoidentifyconservative two-phasefrictional resistances forSWSystempipingandcomponents.

Additionally, baseduponengineering judgement itwasdecidedthatminimumlakelevelelevation andmaximumlaketemperature wouldprovideconservative resultsfortheoverallCRFCheatremovalcapability inthetwo-phase flowanalysesthatwereperformed.

Engineering judgement wasalsousedwithinthetwo-phase flowdesignanalysesformodelingofthosecomponents andparameters thatarenotexpectedhaveasignificant impactonthefinaltwo-phase flowresults.3.Determine theuncertainty inthewaterhammerandtwo-phase flowanalyses, explainhowtheuncertainty wasdetermined, andhowitwasaccounted forintheanalysestoassureconservative resultsfortheGinnaplant.Response:

RG8~Eaddressed uncertainties inthetwo-phase flowanalysesbyusingconservative inputsandassumptions asdescribed beloworbyperforming sensitivity studieswhenitwasnotcertainoftheconservative natureofaninputorassumption.

Forexample,duringthedetermination of"worstcase"scenarios forinvestigating effectsoftwo-phaseflow,thefollowing conservative caseswereconsidered:

a.TwoandfourCRFCunitoperations werestudiedseparately.

b.Servicewaterinlettemperature of85Fwasused,althoughthemaximumsystemdesigntemperature is80F(Reference 5).c.OnlyoneoffourSWpumpsisconsidered available.

RAIResponseGL96-06'age 9d.Consideration ofboundingcasesofcompletely cleanandcompletely fouledtubesperdesignrequirements.

Confirmthatthewaterhammerandtwo-phase flowloading'conditions donotexceedanydesignspecifications orrecommended serviceconditions forthepipingsystemandcomponents, including thosestatedbyequipment vendors;andconfiI7nthatthesystemwillcontinuetoperformitsdesign-basis functions asassumedinthesafetyanalysisreportforthefaciltity.

Response

Utilizing theassumptions asdescribed intheresponsetoquestion1,RG&Eevaluated theimpactofwaterhammer andtwo-phase flowonthepipingsystem,components andsupports.

Structural integrity oftheSWsystempressureboundary(piping,components, andsupports) willbemaintained.

RG&Ewillperformmoredetailedanalysesofthepotential waterhammer effectsbasedupontheresultsoffutureEPRIresearcheffortsasdescribed inquestion1response.

Intheevaluation of"worstcase"scenarios foreffectsoftwo-phase flow,itwasconfirmed thatminimumheattransfercapacityofeachCRFCunitisstillmaintained at54.6MBtu/hr.Consequently, theCRFCandSWsystemswillcontinuetoperformitsdesignbasisfunctionasconsidered inGinnaaccidentanalysis(Reference 13).5.ProvideasimpltJied diagramofthesystem,showingmajorcomponents, activecomponents, relativeelevations, lengthofpipingruns,andthelocationofanyortJicesandflowrestrictions.

Response

Simplified diagramsofGinnaCRFC/SWsystemsshowingthoseitemsrequested intheRAIareattached.

Attachment 1:Schematic DiagramShowingSWSystemSupplyTrainstoCRFC's.Attachment 2:Simplified PipingLayoutShowingSWPathsToandFromCRFC's.

RAIResponseGL'6-06'age 10RKliX<RKNCENIII~4663IsUg4133IIyTohronSafcORelatedLoads(Qultcrs) 86464IITTp99ELAP18414'4~/3385I,/PPA8--4114~826F323E28258T'fPICALOUILETPIPINGFROr/'ICFRC'STDDISCHARGE CANAL~88+'~FIANCESSeTYPICAL585.I-P311E28758Tpd)168EL25858,)5618'IS24E.U)3PUUI525,UP251,'Ur.I'5.8')PUI//4)~)68682'8,A63~SS8'46684g5erl8'Itr668~443rd958,e.P328/EL258258IP312EI2565erj'!'r9783)$6'56~4Tleh%53"4INLETSTYP3"28,/Tr,)5gb249Wn214T't'FTCAL

.'NiETPIPINlCFROMS'P/PUMIPS,TOCFrC'S2313'662ATACHMIENT RESPONSETOGENERICL.rTER-'7---S6RAISlMPLiiIEDA'(0JTOFCRFC/S7,89'YSTEM7