ML17326A471

Experimental Investigation of Air Entrainment at Reactor Containment Sump Due to Break & Drain Flows.

ML17326A471
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Site:	Cook
Issue date:	12/31/1979
From:	JANIK C R, NOREIKA J F, PADMANALHAN M ALDEN RESEARCH LABORATORY
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ML17326A472	List: ML17326A471 ML17326A486
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1-80-M178PF, NUDOCS 8002010499
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EXPERIMENTAL INVESTIGATION OFAIRENTRAINMENT ATAREACTORCONTAINMENT SUMPDUETOBREAKANDDRAINFLOWSDONALDC.COOKNUCLEARPOWERSTATIONbyMahadevan Padmanabhan JohnF.NoreikaCarlR.JanikResearchSponsored byAmericanElectricPowerServiceCorporation Docket885,,+igo~>0>~mui~O<yy0fOoeumme-~

~."8.">>+-YWa(vrag~n(~ccarRye~GeorgeE.Hecker,DirectorALDENRESEARCHLABORATORY WORCESTER POLYTECHNIC INSTITUTE HOLDEN,MASSACHUSETTS December1979 ABSTRACTAmericanElectricPowerServiceCorporation (AEPSC)authorized theAldenResearchLaboratory (ARL)ofWorcester Polytechnic Institute (WPI)tocon-ductextensive hydraulic modeltestingoftheReactorContainment SumpoftheDonaldC.CookNuclearPowerPlant,Units1and2.Themodelstudieswereconducted intwophases.Aseparatereportofthefirstphaseofthemodelstudiestoinvestigate vortexing, swirl,andinletlosseswassubmitted earlier(ARLReportNo.108-78/M178PF, September 1978).Themainpurposeofthesecondphaseofthemodelstudiesreportedhereinwastoverifythatthereactorcontain-mentsumpwouldperformsatisfactorily withoutthedevelopment ofobjec-tionableair-entrainment duetobreakflowanddrainflowimpingement throughthewatersurfacenearthesump.Suchpossibleair-entrainment couldaffecttheoperation ofthepumpsintheEmergency CoreCoolingSystem(ECCS)duringtherecirculation mode.AmodelbasedonFroudesimilarity wasdesignedandconstructed toascaleof1:2.5toincludethesumpandthesurrounding areaofthecontainment buildingwithallthestruc'tures thatcouldinfluence theapproachflow.Revisions tothesumpconfiguration basedon'thevortexing andswirlstu-diesconducted earlierwereincorporated inthemodel.Possiblescaleef-fectsofmodelingairentrainment duetojetimpingement wereconsidered andasuitabletestprocedure wasdeveloped involving testingathigherthanFroudescaledjet.velocities andsuctionpipevelocities.

Testswereconducted incorporating variouspossibleflowandpumpcombinations, alongwithpossiblebreakanddrainflowsnearthesumparea,including differ-entpossiblescreenblockage.

Itwasdetermined thatredirecting oficecondenser drainpipesawayfromthesumpareawasdesirable toreduceexcessive airentrainment withinthesumpandtoeliminate airbubblesbeingcarriedtothesuctionpipesundercertainscreenblockageconditions.

Breakflowimpingement testsdidnotindicateanysignificant air-entrainment and,hence,nomodifications inthesumpgeometryitselfwasfeltnecessary.

TABLEOFCONTENTSPacaeNo.ABSTRACTTABLEOFCONTENTSINTRODUCTION PROTOTYPE DESCRIPTION ReactorBuildingTheContainment Recirculation SumpBreakFlowLocations Operating CasesforTests2234AIRENTRAINMENT DUETOJETIMPINGEMENT SIMILITUDE FroudeScalingSimilarity ofAir-Entrainment DuetoJetImpingement 910MODELDESCRIPTION ANDINSTRUMENTATION 14GeneralLayoutSupplyLoopforBreakandDrainFlowsModelingofBreakFlowsModelingofDrainFlows14141516TESTPROCEDURE 16ModelingofAir-Venting SystematTopCovers18~RESULTS18Air-Entrainment duetoDrainFlowAir-Entrainment duetoBreakFlowsSumpModifications andRetesting AirVentingatDownstream TopCover18192121CONCLUSIONS REFERENCES TABLESFIGURESPHOTOGRAPHS 2225 INTRODUCTION Thereactorcontainment buildings oftheDonaldC.CookNuclearPowerStation,Unitsland2,areprovidedwithemergency corecoolingsys-tems(ECCS)designedtocooltheshutdownreactorcoresandthecon-tainments intheeventofalossofcoolantaccident(LOCA).TheECCSinjectswatertomaintaincorecoolingand,initially, thewaterforthisisdrawnfromtherefueling waterstorage"tank(RWST).Whenthewaterlevelinthistankisdepletedtoapredetermined level,theECCSisswitchedfrominjection torecirculation mode.Atthispoint,waterisdrawnfromthe,containment recirculation sumpcontaining wa-terdrainedfromthebreak,waterfromtheicecondenser

meltdown, andwaterfromthecontainment spraysystem.Theapproachflowtothesumpisaffectedbytheequipments andappurtenant structures intheflowpath.Thewaterlevel,thepumpdischarges, andthewatertemperature couldvaryoverawiderangeduringtherecirculation mode,whichlastsforanextendedperiodoftimetoprovidesufficient heatremoval.The,breakflowanddrainflowvarywithtimeandtheyimpingeonthewatersurfaceasahighvelocityjet.Itisveryimportant thatnoadverseflowconditions causedbybreakandicedrainflowjetsexistwithinthesumporthesuctionpipesthatcouldaffectperformance ofthepumps~TheAldenResearchLaboratory (ARL)wasauthorized byAmericanElectric'ower ServiceCorporation (AEPSC)toconstruct andtestamodeloftheDonaldC.CookNuclearPowerStationcontainment recirculation sumpwiththeobjectofinvestigating freesurfacevortexformation, swirl,inletlosses,airentrainment duetoimpingement, oranyotherundesirable flowconditions thatcouldadversely affecttheperformance oftheRe-sidualHeatRemoval(RHR)andContainment SprayPumps(CTS),andSafetyInjection (SI)PumpsoftheEmergency CoreCoolingWaterSystem(ECCS)intherecirculation mode.Operating conditions involving awiderangeofvariouspossibleapproachflowdistributions, waterdepths,watertemperatures, screenblockageeffects,andpumpoperating combinations weretobetestedinthemodel.Ifpotentially undesirable flowcondi-

,-2tionsoccurred, modifications inthesumpconfiguration weretobede-veloped.Thefirstphaseofthemodelstudywastheinvestigation ofairentrainment duetovortexing, suctionofentrapped air,swirlinthesuc-tionpipes,andtheinletlossesatthesumpandthedetailsofthisphasewereincludedinaseparateARLreport(1).Thisreportpresentsthefindingsofthesecondphaseofthestudyin-volvingbreakanddrainflowimpingement andinclu'des adescription oftheprototype andmodel,andsummarizes conditions investigated, simi-litudeconsiderations, testprocedures, instrumentation, interpretation ofresults,andconclusions.

PROTOTYPE DESCRIPTION ReactorBuildinThereactorbuildingiscircularinplanwithtwoconcentric outerwalls;Jnamely,thecranewallandthecontainment wall,withinnerradiiof41.5ftand57.5ft,respectively.

Thesteamgenerators, reactorcoolantpumps,containment cleanupfilterunits,andtheconnected accessories arealllo-catedintheportionbetweenthereactorchamberandthecranewall,asseeninFigure1.Theannularportionbetweenthecraneandcontai:nment wallsaccommodated thevariouspipes,valves,airducts,andcablesforvariousoperating systems,suchasblowdown, coolingwater,ventilation, andliquidwasterecycling.

TheContainment Recirculation SumTheContainment Recirculation sumpislocatedclosetothecranewallbe-tweenthesteamgenerator number2andreactorcoolantpumpnumber2(ex-tendingfrombearing120to150degreesapproximately),

asmarkedinFi-gure1.Thesumpismoreorlessrectangular inplan,about18ftlongand10.5ftwide,withthecranewalldividingitintotwoportions.

Recirculation flowenterstheupstreamportionthroughstainless steelgratingsandscreensprovidedattheentrance, continues downandunderthecranewall,andfinallyentersthesuctionpipes.Figure2showsthesumpdetailsandillustrates thattheupstreamportionwouldhaveafreesurfacewhilethedownstream portionwouldbeunderpressure.

Thetopslabofthedownstream portionofthesumpisprovidedwithasingleairventpiperunningupwardthroughthecranewall.ThesumpfloorisatEL591ft1inch,whereasthebuildingfloorisatEL598ft9-3/8inches.Theaverageapproachvelocityupstreamofthegratingwouldbeabout0.34fpsattheminimumsubmergence (EL602ft10inches).Thetwooutletpipesare18inchesindiameter(Sch.40),andarepro-videdwithbellmouth entrances and24inchdiameterguardpipes.Thesuctionpipesrundownwardataninclination of13'34'ohorizontal, asshowninFigure2.ThecenterofthepipeentranceisatEL595ft6inches,andeachpipeisconnected toavalveatEL589ft9inches.Asindicated inFigure1,alowersump,rectangular inplan(about2ft4inchesby4ft,10inches),and7ft8-3/8inchesdeep,isprovidedadjacenttothemaincontainment sumptoallowforproperdrainageinnormalconditions.

Thissumpisconnected tothemaincontainment.

sumpbyan8inchdiameterpipe.BreakFlowLocations Thepossiblebreakflowlocations inthesumpvicinity(provided byAEPSC)arelocatedinthecross-over, highpressurepipeconnecting thereactorcoolantpumpandsteamgenerator asindicated inFigure3.Therearesixbreaklocations inthisloopwithtwoadditional breaklocations, oneeachinthe3inchand2inchpipesattachedtotheloopatthebottomstraightportion.Thehotlegjoiningthesteamgenerator tothereactorhasonebreaklocation.

Thesixbreaksinthecross-over loopandtheonebreakinthehotlegareallcircumferential typebreaks.The3inchand2inch pipebreakswillcausecircularjetsissuingvertically upordown.Thebreakarearesulting fromtheaxialdisplacement forthebreaksinthecross-over loopandhotlegisapproximately 25.0squareinches.Table1indicates therateofbreakflowfollowing aLOCA.Thefouricecondenser drainflowlocations closetothesump(fourloca-tions)areindicated inFigure4.Thedrainsarel2inchesindiameterandterminate horizontally atabout36ftfromthebuildingfloor.Thedrainsmaynotbeflowingfullformostofthetime.Thedrainflowratefollowing LOCAisgivenbythecurveshowninFigure5.Thebreakflowanddrainflowlocations willbeidentified hereafter inthisreportbythenumbersgiveninFigures3and4.0eratinCasesforTestsThedischarge andsubmergence conditions atthesumpwouldchangewiththedifferent operating sequences fromtheinstantofaLOCA.Thefol-lowingsystemoperations wereconsidered important ininvestigating thehydraulic performance ofthesump:l.9500gpmithroughonesuctionpipe-Thissimu-latestherunoutcondition ofoneECCStrainuponcompletefailureoftheothertrain.2.7700gpmpersuctionpipe,bothpipesoperating

-Thissimulates therunoutcondition ofECCSpumpswithbothtrainsoperating.

3.9500gpmthroughonepipeand3600gpmthroughtheother-,Sameascase1exceptthatthecon-tainmentspraypumpfromtheothertrainisatrunoutflowrate.

ShouldaLOCAoccurinanyofthebreaklocations described earlier,theECCSpumps,whicharealignedtotherefueling waterstoragetank(RWST),wouldinject350,000gallonsofboratedwaterintotheprimaryloopbe-foretherecirculation sumpiscompletely used.OnetrainofECCSpumpswouldbeswitchedtotherecirculation sumpwhenthewaterlevelintheRWSTreachesapredetermined lowlevel,thetimeforthisbeingabout10minutesafterthestartofECCS.ItisnotuntiltheRWSTreachesthelowestlevelthatthesecondtrainofECCSpumpswouldbeswitchedtotherecirculation sump.Atthistime,theentire350,000gallonswouldhavebeenpumpedintothesumpviatheprimaryloop.Awaterlevelof602ft,10inchesistheelevation atwhichthefirstECCStrainsuctionsupplywouldbeswitchedfromtheRefueling WaterStorageTank(RWST)tothecontainment recirculation sump.AwaterlevelofEL606ftwillbethepointatwhichthesuctionsourceofthesecondstringofECCSwouldbeswitchedfromtheRWSTtothecon-tainmentrecirculation sump.Theabovelevelsarecalculated byAPESCassumingthatthebreaksin'heprimarysystemoccurinsidethebiological boundary.

Thisassumption re-sultsinthelowestpossiblecontainment levelssinceitpostulates thatapproximately 128,000gallonsoffluidmustspillwithinthebiological barrierbeforeanyfluidspillsintotherecirculation sumpcavity.This,ofcourse,isconservative andtheabovewaterlevelsareusedformodeltestswithdrainflowsbutnobreakflowsnearthesumpportion.=

Jetimpingement modelingwithbreakflownearthesumpisbasedonabreakintheprimarysystemoccurring outsidethebiological boundary(ifitwereinside,itcouldhavenoeffectonthesump).Therefore, the128,000gal-lonswhichwasconsidered unavailable withinthebiological boundaryisnowavailable tosupplyadditional fluidinventory outsidetheboundary.

Sincethecontainment waterleveloutsidetheboundarywillriseapproximately 1ftperadditional 28,000gallonsoffluid(asperAPESC),thetotalrisewillbeapproximately 4.5ft.Thenewwaterlevelswouldthenbe607ft4inchesforfirstECCSswitchover and610ftforsecondECCSswitchover.

Table2summarizes thesystemoperations, eachofwhich,forconvenience, willbeidentified bythecasenumberhereafter inthisreport.Thewatertemperature ofthebreakflow, whichwouldbecollected inthesump,couldbeashighasl90'F.Acontainment pressureofupto3.0psigwouldbepossible.

AIRENTRAINMENT DUETOJETIMPINGEMENT Highvelocityjetsimpinging onawatersurfaceareknowntoproducecon-siderable airentrainment.

Ifsuchacondition existsveryclosetothesump,theapproachflowwilldrawwithitalargenumberofairbubblesintothesump.Fortheparticular sumpconfiguration oftheD.C.Cookplant,allbubbleswhichhaverisevelocities lessthanthedownwardvelocityoftheflowintheupstreamportionofthesumparelikelytobecarriedunderneath thecrane'wall.Thebubblesmaygetentrained inthemainflowtowardsthesuctionpipes,andwouldbe'rawnintothepipes.Ifsufficient retention timeisavailable, thebubblescouldreachthetopcoverandgetcollected orescapethroughtheventingsystem,depending onitseffectiveness.

Bubblescollected onthetopcovermaycoalescetoformairpockets,andtheseairpocketscouldbedrawnintermittently intothesuctionpipesasslugs,orcouldhelpformair-corevortices.

Itisevidentthatevenalowairconcentration inthesuctionpipes,suchas5%,couldlowertheefficiency ofthepumpconsiderably (2).Further,air-water mixtureflowcouldgeneratepressurefluctuations ontheimpeller.

Hence,airentrainment isrecognized asapotential adversecondition tobeexamined.

SIMILITUDE Thestudyofdynamically similarfluidmotionsformsthebasisforthede-signofmodelsandtheinterpretation ofexperimental data.Thebasicconceptofdynamic,similarity maybestatedastherequirement thattwosystemswithgeometrically similarboundaries havegeometrically similarflowpatternsatcorresponding instantsoftime(3).Thus',allindivi-dualforcesactingoncorresponding fluidelementsofmassmusthavethesameratiosinthetwosystems.Thecondition requiredforcompletesimilitude maybedeveloped fromNewton'ssecondlawofmotion:F.=F+F'+F+F ipgvtwhereF.=inertiaforce,definedasmass,M,timestheiacceleration, aF=pressureforceconnected withorresulting fromthemotionF=gravitational forcegF=viscousforcevF=force'uetosurfacetensiontAdditional forcesmayberelevantunderspecialcircumstances, suchasfluidcompression, magneticorCoriolisforces,butthesehadnoinfluence onthisstudyandwere,therefore, notconsidered inthefollowing develop-ment.Equation(1)canbemadedimensionless bydividingallthetermsbyF..1Twosystemswhicharegeometrically similararedynamically similarifbothsatisfythedimensionless formoftheequationofmotion,Equation(1).WemaywriteeachoftheforcesontherightsideofEquation(1)as:

F.PFg2netpressurexarea=adpL13specificweightxvolume=ayL2F=shear,stressxarea=aphu/hyxarea=cpuLv3~3FtF.isurface.tensionxlength=aaL43222densityxvolumexacceleration

=apLu/L=apuL55wherea,a,etc.=proportionality factorsL=representative lineardimension hp=netpressure=specificweight=dynamicviscosity a=surfacetensionp=densityu=representative velocitySubstituting theabovetermsinEquation(1)andmakingitdimensionless bydividin'g theinertialforce,weobtain1-22-23-14-2-E+-F+-R+-W=1a5a505a5(2)whereE=InertiaForce=Eulernumber~PressureForceuF=-/gz,InertiaForce=Froudenumber~PressureForce uLR=-u/vInertiaForce=ReynoldsneerViscousForceW=~alps,InertiaForce=Webernumber~SurfaceTensionForceSincetheproportionality factors,n,arethesameinmodelandproto-type,completedynamicsimilarity isachievedifallthedimensionless groups,E,F,R,andW,havethesamevaluesinmodelandprototype.

Inpractice, thisisdifficult toachieve.Forexample,tohavethevaluesofFandRthesamerequires.

eithera1:1"model"orafluidofverylowkinematic viscosity inthereducedscalemodel.Hence,theacceptedapproachistoselectthepredominant forceanddesignthemodelaccording totheappropriate dimensionless group:Thein-fluenceofotherforceswouldbesecondary andare.calledscaleef-fects(3).Specialtestingprocedures maybeestablished todetermine ortoaccountforscaleeffectsapproximately butusuallyconservatively.

FroudeScalinModelsinvolving afreesurfaceareconstructed andoperatedusingFroudesimilarity sincetheflowprocessiscontrolled bygravityandinertiaforces.TheFroudenumber,representing theratioofinertiatogravi-tationalforce,F=u//gs(3)whereu=averagevelocityinthepipeg=gravitational acceleration s=submergence was,therefore, madeequalinmodeland.prototype (4) 10wherem,p,andrdenotemodel,prototype, andratiobetweenmodelandprototype, respectively.

Inmodelingofanintakesumptostudytheformation ofvortices, itisimportant toselectareasonably largegeometric scaletoachievelargeReynoldsnumbersandtoreproduce thecurvedflowpatterninthevici-nityoftheintake(4).Ageometric scaleofL=L/L.=1/2.5wasrmp'hosenforthemodel,whereLreferstolength.AthigherReynoldsnum-ber,anasymptotic behaviorofenergylosscoefficients withReynoldsnumberisusuallyobservedinsimilarflows.Hence,withF=1,therbasicFroudianscalingcriterion, theEulernumbers,E,willbeequalinmodelandprototype.

Thisimpliesthatflowpatternsandlossco-efficients areequalinmodelandprototype.

FromEquation(4),usings=L,thevelocity, discharge, andtimescaleswere:0.5rr(5)Q=Lu=L22.5rr-rr(6)0.5rrSimilarit ofAir-Entrainment DuetoJetIminementDimensional AnalysisThemajorparameters influencing therateofaerationofarectangular jetimpinging onapoolofwaterare(5):a.Thedepthoffall(H)b.Thejetvelocityatimpact(u.)c.Jetwidthbandthickness dd.Minimumimpactvelocitytocauseairentrainment, u'.e.Thejetperimeter, pf.FroudenumberF.,ReynoldsnumberR.,andWebernumberW.ofthejetj' Forlargescaleair-entrainment causedbyhighvelocityjetsofrelatively largethickness, theeffectofR.andW.arenegligible (5).Hence,there-jjlativeairconcentration (volumetric quality)g,isgivenby:HB=f(F.,-,~,~)

3du'.dj(8)Theminimumimpactvelocityforair-entrainment, u.isabout3.6fps(5),jandisconsidered aconstantindependent ofotherjetparameters.

Basedonexperimental data,reference (6)gives0.446u.B=K(-)(-)(1-~)pduwhereKisafunctionofF.,butmoreorlessindependent ofF.ifF.isjjgreaterthan10.Hence,b0.4468=-=(-)(d)mrgpprdru.(1-~)3(10)assumingF.isgreaterthan10formodelandprototype.

jIfthebreakareaismodeledtochosengeometric scalewithanassumedbreakwidthandthickness andthebreaklocations arealsocorrectly mo-deledtothegeometric scale,thenb/pandH/d"valuesareconceivably thesameinmodelandprototype.

However,inthisstudy,onlythebreakareaandheight,H,areknownbeforehand whereasthevalues'of b,p,anddareassumedmakingsurethattheirinfluence ontheproblemofconcernisnotoverlooked.

FromEquation(10),if(b/p)and(H/d)areequaltounity,()willberrrequaltounityonlyifthejetimpactvelocityismadeequalinthemodelandprototype, u'.beingaconstant.

However,thisispossibleonlyifthejchosenmodelislargeenough.Also,ifthevaluesofH,p,anddaretoosmall,scaleeffects>suchasduetotheinfluence ofsurfacetension,mayresult.Inthepresent.study,thescaleof1:2.5isconsidered sufficient bylarge.

12B.BubbleRiseVelocities Highvelocityjetsofwaterimpinging onastagnantwatersurfaceproduceaswarmofbubbles,theinteraction betweenthebubblescausingareducedrisevelocitycomparedtothatforsinglebubbles(7).Theentrained aircouldbeintheformofbubblesofvaryingsizes.Within,awiderangeofdownfalljetvelocities, thecorresponding bubblesizerangeshavebeenobservedtodifferverylittle(8).Thismeansthatthemodelandproto-typearelikelytohavemoreorlessthesamerangeofbubblesizes,evenwhenthejetvelocities andheightsoffallaremodeledusingtheFroudelawofsimilarity.

Therisevelocityofbubblesaredependent ontheirsizesandtheairconcentration, B(7),andhencetherisevelocities arenotsimulated toFroudevelocityscalewhenamodelisoperatedonFroudelaw.Air-entrainment measurements inamodeloperatedonFroudelawdonotpredicttheairconcentrations intherealsituation, asevidentfromEquation(10).Infact,theprototype islikelytohavehigheraircon-centrations duetohigherjetvelocities.

Asthebubblerisevelocities arehigherwithlowerairconcentrations forsamebubblesizeranges,themodelmayhavehigherrisevelocities thantheprototype, whereasscaledflowvelocities arelowerinthemodel.ThissuggeststhatthemodelcannotbeoperatedonFroudelawalonetoobtainanymeaningful resultsonairentrainment andonairbeingdrawnintothesuctionpipes.C.Entrainment ofBubblesintoSuctionPipesAsdiscussed intheabovesections, thesamebubblerisevelocities andrelativeairconcentrations couldbeexpectedinthemodelduetojetimpingement, providedthejetimpingement velocityinthemodelisthesameasthatintheprototype andallthelinearjetdimensions aremo-deledtothegeometric scale.Thequestionofhowtoscalethemodelflowsthroughthesuctionpipes(whichalsogovernsapproachvelocities) mustalsobeaddressed.

13Referring toFigure6,letusconsiderabubbleatalocationxftfromPthesumpentranceandyftbelowwatersurfaceintheprototype.

LetP(u.)bethebubblerisevelocityandlet(u)betheapproachvelocitypaptothesump.Thedownwardvelocityofwaterinthesumpformaximumflowoperating conditions couldbeashighas0.75fps,whichismuchhigherthantherisevelocities ofmostofthesmallsizebubbles(lessthan1cm).Hence,itisreasonable toassumethatanysmallbubblethatcouldreachthesumpwillbecarrieddownthesumptothedownstream sideofthewall,withareasonably goodchanceofbeingdrawntothesuctionpipes.Therequirement forabubbletoreachthesumpis(u)-,(u)PPSimilarly forthemodel,ymxm(u)-(u)mm(12)Ifthemodelproducesthesamebubblesizerangeasintheprototype andthesameairconcentrations duetojetimpingement, then(u.)willbeamthesameas(u.).Ifthemodeljetimpingement locations andwater>Pdepthsarefixedtothegeometric scaleL,wegetr'myxm-=LxrP(13)BasedonEquations (ll)to(13)forsimilarity ofbubblemotion,itisessential tohave(u)=(u)pm(14) 14Thismeanstheapproachvelocities inthemodelandprototype shouldbethesame.This,bycoincidence, isthesameasthe"equalvelocityrule"usedinthemodeltestsforinvestigating vortexseverities.

Theflowpatternsinthesumpportiondownstream ofthecranewalltothesuctionpipescanbeconsidered similarbetweenthemodelandprototype, beingclosedconduitflowatsufficiently highReynoldsnumbers.MODELDESCRIPTION ANDINSTRUMENTATION GeneralLaoutAphysicalmodelof,thecontainment sumpandaportionofthereactorbuild-ingformingtheapproachtothesumpwereconstructed toageometric scaleofapproximately 1:2.5onanelevatedplatform, asshowninPhotograph l.Detailsofthemodelconstruction, dimensions, andgeneralpipingarrange-mentareincludedinanearlierARLreport(1).Su1LooforBreakandDrainFlowsFigure7andPhotograph 2showthearrangement ofsupplypipesforbreakanddrainflows.A75HPhighheadpump(300ft)wasusedtorecirculate thewaterfromthemodel(takingsuctionfromalocationbehindtheflowdistributors) throughthebreakanddrainflowpipes.Theseparatesupplypipesconnected tobreakanddrainlocations, eachcontained acalibrated orificemeterandabypasslineforflowmeasurement andadjustment.

Thesupplypipeforbreakflowendedinaflexiblehosewhich,inturn,wasattachedtoanozzleoracircumferential pipering(depending uponthetypeofbreaktobemodeled)atthedesiredlocation.

Thepiperingwasessentially acircumferential ringof2inchdiameterpipefastenedaroundthebreakpipeattheappropriate locationandwasprovidedwith 15slots1/8inchwideand1'inchlongandatabout1inchspacingforhalfthecircumference atadesiredangle,asshowninPhotograph 3.Theopenareaoftheslotswaskeptasthescaledareafromtheassumedprototype breakarea.Onlyhalfthecircumference wasprovidedwithslotstomaketheflowdirectedtowardsthesump,asaconservative assumption.

Theringwassetsoastomaketheslotsfacingthesump-andtheslotswerecutatabout60'othehorizontal soastodirecttheflowrightatthesumpentranceontothewatersurface.Thissimulated rectangular jetsfromcircumferential breaks.Anozzleofsuitablediameter(givingthesameflowareaatthebreak)wasusedwhenacircularjetwassimulated.

Thesupplypipefordrainflowendedatthemodeleddrainlocations, withaflexiblehoseincorporated suchthatthepipeendcouldbedirectedatadesiredlocation.

Thepipesizesscaledtheprototype draindiameters.

ModelingofBreakFlowsBreakflowlocations 1and2(Figure3)weremodeledasasinglelocation, aswere4and5,asthesetwolocations areveryclosetoeachother.Cross-over breaklocations 3and8,location9inthehotleg,andloca-tions,6and7inthe3inchand2inchpipes,respectively, weremodeledseparately.

Theareaofthecircumferential breaksinthemodelwasscaledfromthegiven(assumed) prototype areaof25squareinches.Arectangu-larjetformedbyslotsdescribed earlieralonghalfthecircumference ofthepipefacingthesumpwasmodeledandtestedatall,locations inthecross-over loopandhotleg.The3inchand2inchpipebreaksweremo-deledonlyascircularjetssimilartothosepossibleintheprototype.

Photograph 4showstheslottedcircumferential pipeatlocation2andthebreakflowissuingoutofitdirectedatthesump.Thejetvelocityofimpactatthewatersurfacewascalculated fortheprototype breaksusingthebreakflowandareaandheightoffallas,(15) 16whereu.istheexitvelocitygivenbyQ/A,theratioofbreakflowtojeareaandHistheheightoffall.Themodelbreakflowrequiredtogivethesamevalueofu.wasthencalculated asthebreakareaandheightoffallinthemodelareknown.Thisvaluewassetinthemodel.ModelinofDrainFlowsIcecondenser drainflowlocations 1and2(Figure4)weremodeledbeingveryclosetothesump.Locations 3and4wereconsidered unimportant asthedrainflowjetatlocation3wouldmostlybeintercepted bythesteamgenerator anditssupportsandthejetatlocation4wasconsidered toofartherawayfromthesump.Inmodelingthedrainflows,itwasconsider-edimportant tosimulatethedrainpipediameterandheightofthedraintothegeometric scale.Thepointofimpingement ofthedrainflowjetonwatersurfacewaslocatedfortheFroudescaledflowthroughthedrain,asthepathofdrainflowessentially wasgravitycontrolled.

Oncethisimpactpointwaslocated,theflowwasincreased togiveprototype impinge-mentvelocity, atthesametimeadjusting theflexiblehoseendofthemodeldrainsuitablytokeeptheimpingement regionthesame.Theproto-typevelocityofimpingement wascalculated usingEquation(15).TESTPROCEDURE Teststoinvestigate air-entrainment inthesumpareaduetotheimpinge-mentofhighvelocitybreakanddrainflowsonthewatersurfacewereconsidered necessary forbreaklocations ordrainlocations closetothesumpsothatimpingement couldtakeplaceintheimmediate vicinityofthesump.Itwasrealizedthataircouldbedrawnintothesuctionpipeseitherdirectlyfromtheimpinging jetorafterasufficient quantityofsmallbubblescollected onthetopcoverofthesump.Theobjectionable limitofairentrainment wasconsidered todependonthepump,andthislimitwasnot,known.Ingeneral,anyairentrainment oflargebubblesin-tothesuctionpipeswasdeemedobjectionable.

Asdiscussed inearliersectionsofthereport,sincebubblesizesandbubblerisevelocities" donotscaleinaFroudemodel,specialtestpro-cedureswereusedtoapproximate theprototype conditions.

Thetest'rocedure followedisdescribed below.a.Thebreakflowordrainflowareasandtheirlocations weremo-deledbasedonthegeometric scaleofthemodel.Breakflow types,whethercircumferential orcircular, wereusedinde-cidingthejetdimensions togivetheproperscaledarea.b.Onlyonebreakwasconsidered possibleatatime.Aworstpos-sibledirection ofthejettowardsthesumpentrancewasassum-ed.Fordrainflowjets,animpactpointwasdetermined byscalingthecorrectwaterlevelandFroudescaledflowforeachlocationofdrainflow.

c.Thejetflowwasincreased togiveprototype impactvelocities ofthejet,andthejetdirection wasadjustedtokeepthesameimpactlocationdecidedfromstepb.Toaccomplish thereorientation, adjustable connections tothebreaknozzles(orslottedring)ordrainpipeendswereprovided.

d.Themodelwasrunsothatprototype velocities wereobtainedinthepumpsuctionpipescorresponding topossibleprototype flowcombination.

Thesubmergences (ordepthofwaterinthemodel)corresponded togeometrically scaledvalues.e.Air-entrainment inthesumpareaandinthepumpsuctionpipeswasascertained byobserving anyaircollected onthetopcoversofthesumporbeingdrawnintopipes.Photographic documentation asrequiredwasobtained.

f.Ifobjectionable conditions werenoted,modifications suchasaddingbaffleplates,deflectors, airvents,etc.,wereimple-mented.Majorsumplocationorconfiguration changeswereconsidered onlyifabsolutely essential.

18g.Theabovestepswererepeatedforeachwaterlevelandflow.condition andforeachbreakordrainflowlocations.

Also,theeffectsofscreenblockages (upto50%),usingthesameworstblockageschemesderivedfromvortexing tests,wereinvestigated.

~h.Whileperforming thetests,anyincreased vortexactivityduetomodifications wereobserved.

Ifobjectionable air-pulling vorticeswerepresent,alternative modifications weretried.ModelinofAir-Ventin SstematToCoversTheearlierARLstudy(1)onthevortexing behaviorofthesumphadindi-catedthenecessity ofimproving theair-venting atthetopcoversbothupstreamanddownstream ofthecranewall.Fortheupstreamtopcover,itwasrecommended thatonerowof1/2inchdiameterholesbeprovidedatabout18inchesc/c,andtheseholesweremodeledtoscale.Forthedownstream topcover,slopingroofplatesangleduptowardsasingleventpipewasproposedbyAEPSC,asshowninFigure8.Thisvent-ingsystemwasbuilttoscaleinthemodel.Thehorizontal slababovetheslopingplateswas'notmodeled,beingunnecessary.

RESULTSAir-Entrainment duetoDrainFlowDrainflowatthemodeledlocations couldexistforacasewhenthere-circulation modeisinitiated atEL602ft10inches(operating caselaorlbonly)whereasthebreakflowatthelocations inthecross-over leginthevicinityofthesumpmodelhavetobeconsidered onlyforacasewhentherecirculation modeisinitiated atEL607ft4inches.Hence,drainflowjetimpacttestswereconducted firstforonepipeoperation cases(laandlbofTable2).Inthiscase,thesumpentrancewasnot 19submerged, thetopcoverbeingatEL604ft11-3/8inches.Considerable air-entrainment wasgenerated attheimpactlocationasseeninPhoto-graph5.Mostofthebubbles,beinglarge(ofsizesgreaterthan5mm),werenotdrawn,downintothesumpunderthecranewall.However,smallquantities ofrelatively smallerbubbleswerepulleddowntheupstreamsumpportionintothedownstream area,andmostofthesecollected atthetopcoverinthedownstream portion.Theair-ventsystemofsingleventpipeandslopingplates(Figure8)wasnotefficient enoughtoventallthebubblescollected.

Thiscausedaccumulation ofbubblesandoc-casionalpullingofslugsofairintothesuctionpipe(moresowitha50%blockageofsumpscreens).

Itwasdecidedtoextendthedrainflowpipesfartherfromthesumparea,"alongthecranewall,toallowthemtodischarge atasubmerged locationawayfromthesumpentrancearea,therebytotallyeliminating thedrainflowjetimpactinfrontofthesump.Withthischange,furthertestingwascarriedoutwithoutdrainflowmodeling.

Air-Entrainment duetoBreakFlowsA.Unsubmerged BreakLocations Ahighvelocityjetimpactatthewatersurfaceoccurredformodeledbreaklocations 1(or2)and4(or5)(Figure3),whichwerenotsubmerged forthelowestwaterelevation ofEL607ft4inches,atwhichoperating case"laorbwaspossible.

Thesebreaklocations weretestedoneatatime.Eventhoughtheyproducedconsiderable airentrainment, noairbubblesofreadilyvisiblesizeswereseentobedrawnintothesumpdownthecranewall.Thisisbecausethesumpentrancewascompletely submerged withitstopcoverbelowthewatersurface(about1ftinmodelor2.5ftinproto-type)andmostoftheair-entrainment wasinthetopfewinches.Photo-graphs6and7showtheairentrainment atthesurfaceinthesumpareaforbreaklocations 1and4.Thesurfaceairentrainment, althoughcon-siderably, wasrestricted toasmalldepthandnoairbubblesofany 20significant sizeweredrawndeepintothesump.Novisiblequantityofbubblesweredrawnintothepipes,asindicated byobservations throughwindowsinthepipe.Hence,thesumpperformance wasconsidered satis-factorywithregardtoairentrainment duetounsubmerged breakjets.B.Submerged BreakLocations Eventhoughsubmerged breaklocations arenotlikelytoproduceair-en-trainment, particular breakflow orientation couldaugmentanyborder-linevortexactivitybyaddingmoretoanyexistingcirculation.

Withthisinmind,allthesubmerged breaklocations; namely3,6;7',and8,iweretested(Figure3)foralloperating cases.Breaklocations 6and7werecorresponding tobreaksinthe3inchand2inchlinesjoiningthecross-over pipeandwereconsidered asverticalupwardordownwardcircularjets.Thesesubmerged verticaljetsdidnotproduceanysigni-ficantvortexactivitynordidtheycauseanyairentrainment problem's.

Averticalupwardjetwasobservedtoemergeoutofthewatersurface;butwasbrokenintoaspraybyhittingobjectsandwasofnoconcern.Breakflowlocation8wasseentohavelittleinfluence onvortexing andnoproblemsofconcernwerenoticed.Breaklocation3inthebendportionofthepipewhenproperlyoriented, togetherwitha50%blockage[blockage schemes3and5ofARLreportonvortexing (1)]didaddconsiderable circulation toanotherwise weaksur-facedimple,frequently producing astrongvortexwithanaircoreex-tendingafewinchesbelowwater(Photograph 8).Thisvortex'was veryunstableandunsteady, andmovedfromapositioninthecenterofthesumpentrancetoapositionclosetothebreakflowjet,whichcausedadispersion oftheaircoretoastreamofbubblesdirectedtowardsthesump.Thesebubbleswerelargeenoughandhadenoughbuoyancynottobedrawnunderthecranewallintothedownstream portionofthesump.Thistypeofvortexoccurredforbothoperating cases1and2(waterlevels607ft4inchesto610ft0inches).

21SumModifications andRetestinThevortexing described intheearlierparagraph wasoutsidethesump,andthesumpscreensandgratingspresumably actedasvortexsuppressois asnovortexcorewasseenextending intothesump.Ifitisdesiredtoreducethisvortexing, apossiblemethodwouldbetoinstallaverticalstandardfloorgrating,infrontofthehorizontal crossoverpipe,extending overalengthandheighttoobstructthebreakflowjetsfromlocations 3or8,asshowninFigure9.Itwasobservedinthemodelthatagratingof1inchdeepbearingbarsservedtodispersethejetsoastoreduceitscontribu-Ctiontorotational flowfield.Theadditionofthegratingshowedadecreaseinvortexstrengthandfre-fluencyatthelowerwaterlevelfortheonepipeoperation (Photograph 9a).Infrequently, aweaksurfacedimplevortexmovedtowardsthebreakflowjetwhichdispersed fewlargebubblestowardsthesump,however,noneofthesebubblesenteredthedownstream sumpregion.Forbothpipesoperat-ingatawaterlevelofEL610ft,thevortexintensity wasreducedbytheextragratingtoasurfaceswirlandnosignificant activitywaspresent(Photograph 9b).AirVentinat,Downstream ToCoverIngeneral,therightsideofthesumproofdownstream ofthecranewallwasfoundlessefficient inair-venting comparedtotheleftside,wherethesingleair-ventpipeislocated.Sincenoobjectionable rateofairaccumulation andwithdrawal throughthesuctionpipeswerenotedforanyofthetestconditions, thereappearslittleneedforanymodification orredesignofthetopcover.However,someadditional effortsweremadetoevolveadesigntoimprovetheair-venting, incaseitisdesired.Theslopingplatesattachedtotheoriginalhorizontal slabbottomweremodeledalongwiththeventpipe(Figure8).However,thehorizontal slabitselfwasnotincludedinthemodel,beingunnecessary forsimu-latingtheairventingsystem,whichessentially consisted oftheslop-ingplatesandventpipe.Toimprovetheperformance ofthisventsys-22tern,itwasdecidedtoprovideafew1/2inchdiameterholesat5inchesc/cinthemodelalongtheportionsofslopingcoverplateontherightsideofthesumpawayfromthemainventpipe.Asthehorizontal slabwasnotmodeled,theholeswereallconnected toacommonmanifoldlocatedap-proximately atthesameelevation corresponding tothebottomofthehori-zontalslababovetheplate.Thecommonmanifold, inturn,wasconnected toanadditional verticalventpipe.Suchanarrangement wasseentoim-provetheventingsystem,reducingtheaccumulation ofbubblesundertheslopingplate.Thebubbles.continuously escapedthroughtheholesandwereeventually flushedthroughtheadditional ventpipe.CONCLUSIONS Drainflowjetsimpinging infrontofthesumpproducedconsider-ableair-entrainment.

Forlowerwaterlevels(atoraboutEL602ft10inches),thesumpentrancewasnot,submerged (freesurfacepresentinsidesump)andsmallquantities ofsmallersizeairbubblesweredrawnwiththeflowtotheportionofthesumpdown-streamofthecranewall.Inspiteoftheair-venting system,someof-thebubbleswerecollected underthetopcoverandwereoccasionally drawnintothesuctionpipe.Toavoidthis,itisrecommended toredirectthedrainflowatlocations 1and2(Fi-gure4)awayfromthesumpareabyextending thedrainpipesalongthecranewallandpreferably discharging thedrainflowclosetoorbeneaththewatersurfaceinthesump.2.Breaklocations 1,2,4,5,and9(Figure3)couldcauseunsub-mergedhighvelocityjetsimpinging onthewatersurfacenearthesumpentranceforarangeofwaterlevelsbelowthecorres-pondingbreaklocations.

Thesumproofandentrancewouldbesub-mergedforallthepossibleoperating conditions, thesumptopcoverbeingbelowtheminimumwaterlevelofEL607ft4inches.Themodeltestresultsindicated thattheunsubmerged jetscaus-edconsiderable air-entrainment atandneartheimpactregion.However,nonoticeable movementofbubblestothesumpportion downstream ofthecranewallwasobservedfortheabovebreaklocations.

Thiscouldbeduetosufficiently highwaterdepthsandlowapproachvelocities, whichallowbubblereleasetosur-face,andalsoduetothefactthatthesumpentrancewaswellsubmerged (morethan2ft)belowthewatersurface.Hence,noadverseair-entrainment problemswereencountered forunsubmerged breakflow jets.3.Nosubmerged breakflowtestedcausedanyair-entrainment.

How-ever,itwasimportant toassesstheprobablecontributions ofsubmerged breakflowsinaugmenting vortexing toanyobjection-ableextent,asnotedbelow.a.Breaklocations 6and7generated verticalcirculaijetsinthecorresponding 2inchor3inchpipe.Thesejetsweresubmerged foralloperating conditions, andwereseentocausenovortexing problemsevenwith'0%screen'lockages.

b.Breaklocations 4and5(circumferential breaks)weresubmerged forwaterlevelshigherthantheirlocations.

Atthesewaterlevels,modeltestsindicated nosignifi-cantvortexing

problems, evenwith50%screenblockages.

c.Breaklocations 3and8weresubmerged foralloperating conditions.

nBreakflow atlocation8didnotcauseanyobjectionable vortexing problems.

However,breakflowatlocation3wasobservedtostrengthen aweakdye-coretypevortexwhichexistedevenwithoutbreakflows (seeref.1)outsidethesumpscreenbetweentheverticallegsofthecross-over line.Thisvortexwasunstableandintermittent andwasseentohaveanaircoreex-tendingtoafewinchesbelowthewatersurfacewhentestedwith50%screenblockage.

Whensuchanaircoreformed,andthevortexmovedtowardsthebreak,the 24breakflowjetwasseentobreakthecoreintobubbles.Someofthesebubblesenteredthesumparea,butwerelargeenoughtoescapetothesurfaceandwerenotdrawntotheportionofthesumpdownstream ofthecranewall(andhencenotdrawnintosuctionpipes).Asanoption,thisvortexseveritycouldbereducedconsiderably byplacingastandardfloorgrating(2-1/2inchdeepbars)asindicated inFigure9.4.Thereappearslittleneedforanyredesignormodifications of,thesumptopcovers,asnoobjectionable rateofbubbleaccumu-latioqunderneath thesecoverswerenotedforthetestconditions withthedrainflowsredirected.

Therateofairventinginthedownstream slopingtopcoverplatecouldbefurtherimprovedifanadditional ventpipeweretobeprovidedintherightportionofthesumpcover(lookingdownstream) andafewrowsofl-l/4inchdiameterholesatabout.12inchesc/caredrilledonthisportionoftheplate.

25REFERENCES 1.Padmanabhan, M.,"Hydraulic ModelInvestigation of'ortexing andSwirlWithinaReactorContainment Recirculation Sump-DonaldC.CookNuclearPowerStaton,"ARLReportNo.108-78/M178PF, September 1978.2.Murakami, M.,etal.,"FlowofEntrained AirinCentrifugal Pumps,"13thIAHRCongress, Japan,August31toSeptember 5,1969,Vol.2,p.71-0.'.Rouse,H.,HandbookofHdraulics, JohnWiley6Sons,1950.4.Anwar,H.O.,"Prevention ofVorticesatIntakes,"

WaterPower,October1968,p.393.5.Ervine,D.A.,andElsawy,E.M.,"TheEffectofaFallingNappeonRiverAeration,"

IAHR16thCongress, SanPaulo,Brazil,1975,Vol.3,p.390-397.6.Elsawy,E.M.,andMcKeogh,E.J.,"StudyofSelf-Aerated FlowwithRegardtoModelingCriteria,"

IAHR17thCongress, 1977,Vol.1,p.475-482.7.Govier,G.W.,andAziz,K.,FlowofComlexMixturesinPies,VanNostrandReinhold, 1972.8.Chanishvilli, A.G.,"AirEntrainment andVerticalDownwardMotionofAeratedFlows,"IAHR8thCongress,

Montreal, Canada,1959.

TABLES

TABLE1BreakFlows*1.Breaklocations inthecross-over andhotlegs(circumferential breaks)BreakArea=25sq.inches.Maximumflowof540lb/secoccurring at15minutesafterLOCA.2.Breaklocationin3inchSch.160line.TimefromLOCA,secsMassFlowrate(lb/sec)7501000125015001750200025003000116.3114~0ill.3109.0108.5106.0105.0100.03.Breaklocationin2inchSch.160line.TimefromLOCA,secsMassFlowrate(lb/sec)20003000400050006000700080009000444236.533.7532.25313028.75*DetailssuppliedbyAEPSC.

TABLE2Operating CasesTestedOperating CaseNo.Flow/Pipe cg>mRangeofWaterSurfaceElevation Remarksla9500602'10"-606'0"607'4"-610'0"*Runoutcondition ofoneECCStrainuponcompletefailureofother.Leftpipeoperational.

lb9500602'10"-606'0"607'4"-610'0"*Runoutcondition ofoneECCStrainuponcompletefailureofother.Rightpipeoperational.

3a77001x95001x3600606'0"-612'0"610'0"-612'0"*606'0"-612'0"610'0"-612'0"*Runoutcondition ofECCSpumpswithbothtrainsoperating.

Runoutcondition ofoneECCStrain(left);con-tainmentspraypumpfromother,.train atrunoutflow(right).3b1x36001x'9500606sOi612i0'10s0n612s0nRunoutcondition ofoneECCStrain(right);con-tainmentspraypumpfromothertrainatrunoutflow(left).*Applicable forbreakflowtests.

PHOTOGRAPHS

~p5i~t7~1'77'7~(.'.im7A(~A.77)I~jg'y,.'L7151Photograph 1OverallViewofSumpModel(1:2.5Scale) fPJI~DRAINFLOWiS/r~>>i)p'yIgp,',II.",-*'5t:+Ij."rBREAKFLOW Photograph 2ModelSimulation ofBreakandDrainFlows4~I,1$'p/Photograph 3Simulation ofCircumferential BreakArea Photograph 4TypicalCircumferential BreakFlowO;ff.!Photograph 5DrainNowImpingement; WaterLevelEL602'10" lP;tI'llPhotograph 6BreakFlowImpingement; BreakLocation1;WaterLevelEL607'4";Operating Case1~~I'Ill555III*I5IItI,l-5.-'},151'*Photograph 7BreakFlowImpingement; BreakLocation4;WaterLevelEL607'4";Operating Case1 Photograph 8aSubmerged BreakFlow;BreakLocation3;WaterLevelEL607'4";Operating Case1l~~I1(tltPhotograph 8bSubmerged BreakFlow;BreakLocation3;WaterLevelEL610'0";Operating Case2 Photograph 9aSubmerged BreakFlow;BreakLocation3;WaterLevelEL607'4";Operating Case1;WithVerticalGratingforJetInterception (c;Q=mtry%i)1IJPhotograph 9bSubmerged BreakFlow;BreakLocation3;WaterLevelEL610'0";Operating Case2;WithVerticalGratingforJetInterception FIGURES 103o27MODELBOUNDARYHOTLEGR.C.PUMPNO.2~'5xSTEAMGENERATOR NO.20+~+4'12o42'ODELBOUNDARY125o-44'30 24140.30'3151-04"23"0CONTAINMENT VESSEL2f15052215321'.57"0FIGURE1LOCATIONOFSUMPWITHINCONTAINMENT BUILDING GRATINGSCREENEL599'A3/8" OEL591'-1".O.:4.0':i.:i"W'44-Vi~-'4."."Ot.':;..OOj~0~o..%~EL593'-9.3/4"

r49oo'.~4C40

"~'.u:..CRANEWALL'o.u'~'O,'4~oot44EL598'-9-3/8" EL596'-9.1/4"

'r4.~t10'412'-7"9t+tt5t+t~9tt2t9ttSECTIONB-BMINIMUMW.S.E..EL607'4"EL604'-11-3/8" 6oVENT:d.d~~)Odq'~4.'d~O'lt.od~,.'RANEWALL3t+t3t+ttcI-SUMPQ3t+tt3t6ttEL598'-93/8"GRATINGC.44...EL598'-9-3/8" EL596'-9-1/4"

.o.'td'.Orqd0)Od0d.,t..d.q.d<4O~0d.0"ot.0/8tr~C7/pP/a/~88~13o34EL591'-1"'g~"eV'fr~""~!d"':!.t."d:4'~.~4/I+I+Jr'4"DIA.SECTIONA-AEL596'9-1/4" EL595'4"EL591'-1"SECTIONG-CFIGURE2DETAILSOFORIGINALSUMP EL614'-0"STEAMGENERATOR 1EL615'-8.3/4" NOTE:BREAKELEVATION 615'-11"615'.8.3/4" 604'-11-1/2" 608'-2-1/4" 608'.5"HOTLEG5I7II3'5~R.C.PUMP-EL608'-2-1/4" I86-7-M6EL603'-8-1/4" CROSSOVERPIPEEVENTSWITCHOVER OFFIRSTECCSTRAIN(BREAKOUTSIDEBIOLOGICAL BOUNDARY)

SWITCHOVER OFSECONDECCSTRAINWATERLEVEL(CONSIDERING PARTIALICECONDENSER MELTDOWN)

ATSWITCHOVER OFSECONDECCSTRAINSWITCHOVER OFFIRSTECCSTRAIN(BREAKINSIDEBIOLOGICAL BOUNDARY)

WATERLEVELINSUMP607'-4"'10'0"612'0"602'-10"'BASED ONNOICECONDENSER MELTFROMICECONDENSER FIGURE3POSTULATED BREAKLOCATIONS 90180z"IIICECONDENSER DRAINS)(/X/'y;1..'j4F"j5pP'ONTAINMENT SUMP.".i':,'.;.";:)j

//'tlag..23NOTE:a)ICECONDENSER FLOOREL642'.0"b)DRAINCENTERLINE ELEVATION ATEXITEL634'-6"c)ALLDRAINSAREOF12"DIA.PIPEFIGURE4DRAINLOCATIONS 250200150CJCl0100~ONERHRPUMPONRECIRC.II)~TWORHRPUMPSONRECIR.I001020TIME(MIN)406070FIGURE5POSTLOCAFLOWRATEOFEACHICECONDENSER FLOORDRAIN SUCTIONPIPE=::4::'RANEWALLSUMP~~\v~~~o~~~~~~~i~.i~I~'oooo"~o:ouboYu'~~0~~~~BREAKFLOWJETAIRBUBBLE(ARBITRARY)

HWATERLEVEL,'I+%Pi,'I~Jr'".i:,

p$$ub'BUBBLE RISEVELOCITYu:SUMPAPPROACHVELOCITYuI'JETIMPINGEMENT VELOCITYFIGURE6DEFINITION SKETCHFORBUBBLEMOTIONTOWARDSSUMP ICEDRAINS(2PIPES)rrrrrrNOZZLEENDFLEXIBLETUBEORIFICEMETER4"PIPEDRAINFLOWSUMPENTRANCEMODELTANKFLEXIBLEHOSEBREAKLOCATIONORIFICEMETER6"PIPEBYPASSLINEBREAKFLOWOUTLETPIPESPUMPSUCTIONCENTRIFUGAL PUMP(75HP)FIGURE7SCHEMATIC DIAGRAMOFBREAKANDDRAINFLOWSUPPLYPIPINGIN'MODEL 0I-oI-3~O.4.OO"OO~i.3.OaO3o.33~.':.o,t/'fj~ta'.j:tt.o:Pjo.3I.'o'3oto0,o.c'O3o".By2'tt2tt2'~gt~3lt."'"0o6IQtt'4.B1/4"CLITYP.)7tQtt3t6tt2'-7-1/2" 7tPtt1/4"THICKSTAINLESS STEELPLATE15/16"DIA.HOLEFOR3/4"DIA.SELF-DRILLING ANCHORAT1'0"O.C.14'-0"PLAN-SUMPPITROOFIL6"DIA.VENTPIPESTAINLESS STEELBAR1"1"1/4"THICKSTAINLESS STEELPLATESECTIONC-CEL596'-7"~033otEL596'-9-1/4"

'P~1/4"THICKSTAINLESS STEELPLATESECTIONA-AEL596'-9-1/4" 1CALE5/8IN.>3FT.EL596'-7"BOTTOMOFSTAINLESS~

""."ILATLOWPOINT3'3"~7'4"~3'4"I%24"DIAIL24"DIASECTIONB-Bi..'.no'.ts.,~EL596'-9-1/4"

';.~...44~1/4"THICKSTAINLESS STEELPLATESTAINLESS BARFIGURE8IMPROVEDAIRVENTINGATTOPCOVER STEAMGENERATOR EL615'-8.3/4" 6I2IIPROPOSEDVERTICALGRATINGR.C.5PUMP4EL608'-2-1/4" MIN.WATERLEVELEL607'4"FLOOREL598'-9.3/8" 86EL601'-2-3/8" glpllglPll18'-0"NOTE:2-1/2"STANDARDFLOORGRATINGTOBEPLACEDCLOSETOTHEPIPE.FIGURE9POSITIONOFSUGGESTED VERTICALGRATING(OPTIONAL MODIFICATION)