ML17209A630

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Analysis & Evaluation of St Lucie Unit 1 Natural Circulation Cooldown.
ML17209A630
Person / Time
Site: Saint Lucie NextEra Energy icon.png
Issue date: 12/31/1980
From:
INSTITUTE OF NUCLEAR POWER OPERATIONS, NUCLEAR SAFETY ANALYSIS CENTER
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ML17209A629 List:
References
INPO-2, NSAC-16, NUDOCS 8102120262
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IÃPO2%SACl6December1980AnalysisandEvaluation ofSt.L.u.cieUnit1--:.'"':-NaturalCirculation Cooldovzm e'I1s"N'1r.~'ra*4k,emf-.e,.~a"":wP'K'p'(

Ie~4Syo2y@0QtQqNucteerSefetyAnslysls Center*Institute ofNuclearPowerOperations 1

hIJJI'nalysis andEvaluation ofSt.LucieUnit1NaturalCirculation CooldownNSAC-16/)NPO-2December3980PPreparedbyInstitute ofNuclearPowerOperations Atlanta,GeorgiaandNuclearSafety-Analysis Center,PaloAlto,California

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Ig LEGALNOTICEThisreportwaspreparedbytheNuclearSafetyAnalysisCenter(HSAC)operatedbytheElectricPowerResearchInstitute, Inc.(EPRI)andbytheInstitute ofNuclearPowerOperations (INPO).NeitherNSAC,EPRI,INPO,membersofEPRIorIHPO,otherpersonscontributing toorassisting inthepreparation ofthereport,noranypersonactingonthe-behalf ofanyoftheseparties(a)makesanywarrantyorrepresentation, expressorimplied,withrespecttotheaccuracy, completeness or-"usefulness oftheinformation contained inthisreport,orthattheuseofanyinformation, apparatus, methodorprocessdisclosed inthisreportmaynotinfringeprivately ownedrights;or(b)assumesanyliabilities withrespecttotheuseof,orfordamagesresulting fromtheuseof,anyinformation, apparatus, methodorprocessdisclosed inthisreport.tf I!"k'::;;~~,;;<<i;'<<p~>~Wig'<<g<<~

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<<~<<p,,i'.<<<<<<.;0,,~~<<!~<<.<<~<<ABSTRACTAcooldownbynaturalcirculation ofthePressurized llaterReactor,St.LucieUnit1,hasbeenanalyzedbyNSACandINPO.Thisevent'occurred onJune11,1980.Keyitemsofinterestdiscussed

'inthereportinclude:'I1.unexpected formation ofasteambubbleunderthereactorvesselhead,2.initially undetected smalllossofreactorcoolantinventory, and3.additional instrumentation requiredfornaturalcirculation cooldown.

Additional itemsfortheoperators toconsiderwhenemploying naturalcirculation inaPWRarepresented.

Theseitemsshouldbeincludedinprocedures forcon-ductingnaturalcirculation coolingandpl.antcooldown..under natural.circulation.

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4v~"~"gqC$P'-0Q~'f]"

'."~<<"p<~y"'"~'"i>>J~>"'6~';e*jA,LTABLEOFCONTENTSNarrative

...............,.....A~~~Pae~~~~~~1aVE'FindingsandConclusions E-'IAppendices

~~~~~~~~~3SequenceofEvents....................SOENaturalCirculation andPlantCooldown..Radiochemistry andRadioactive Effluents

.PlantProcedures andOperation

..'....~~~RAD~~~~~~~~~OPS~~~~~~~~~T/HOperations DuringNaturalCirculation/Cooldown

.~~~~HCCReference List.........................REFGlossaryofTe'rms,Abbreviations andAcronyms..........GLOS NSAC/INP0Contributors tothisEvaluation W.BrownG.Caldwell0.Gillispie D.Kill(Baltimore Gas&Electric)

.IW.LaymanS.Rosen I

ST.LUCIEUNIT1*NATURALCIRCULATION COOLDOMNON6/11/80NARRATIVE OnJune11,1980anelectrical failurecausedacomponent, coolingwaterisolation

  • valvetoshutoffcoolingwaterflowtothesealsonallfourreactorcoolantApumps.TheSt.LucieplantoftheFloridaPowerandLightCo.wasoperating atnearlyfullpower.Thelossofcoolingwatertothereactorcoolantpumpseals-requiredtheoperators

.toshutdownthereactorinordertoallowthemtostoptheI~reactorcoolantpumps.Thisactionprotected thepumpsealsfrombeingdamagedduetooperation withoutsealcoolingwaterflow.Thereactorcoolantsystemwas~thencooleddownwithnaturalcirculation providing coolantflowtothecoreanddepressurized tothepointwherealowpressureshutdowncoolingsystemcouldbeusedforthefinalstagesofcooldown.

Unexpected behavior'ofpressurizer levelwasobservedapproximately fourhoursafternaturalcirculation wasinitiated.

Evaluations byFloridaPowerandLightCompany,Combustjon Engineering Corp.,institute ofNuclearPowerOperations, andtheNuclear"SafetyAnalysisCenterhaveagreedthattheunexpected pressurizer levelbehaviorwascausedbysteamforma-tioninthereactorvesselhead.Asthepressurizer cooleddown,steamformedinthereactorvesselhead,whichhadbecomethehottestpartofthesystem,dis-placingwaterfromthereactorcoolantsystemintothepressurizer.Theoperators hadnotemperaturereadinginthereactorvesselheadarea.Theanomalous behaviorcontinued foraboutsixhoursuntilthereactorvesselheadhadbeencooled.Evaluation ofthenaturalcirculation cooldownshowsthatdespitetheanomalous

'ressurizer levelbehaviorandthesteamformation inthereactorvesselhead,naturalcirculation continued withoutanyevidenceofperturbation untilforcedcirculation andcoolingwereestablished bytheshutdowncoolingsystem.Todate,twoofthefourreactorcoolantpumpsealshavebeendisassembled andinspected.

Nodamagehasbeenfound.Theremaining twosea'Isarescheduled forinspection.

.operation, December1976.I1h4,R Ii

  • ..I~IEI.FloridaPower.,andLightpersonnel havedetermined thattheinitiating electrical failurewascausedbyanaccumulation ofmoistureinanelectrical junctionboxcontaining aterminalboardforthecomponent coolingwatervalvesolenoid.

Themoisturecamefromasteamleakatanearbypipingflange.Thesteamleakwasrepairedandthejunctionboxwasmadelesssusceptible tomoistureintrusion.

EThreeareasofimportance highlighted bythiseventare:.*1..Unexpected formation ofasteambubbleinthereactorvessel',':2.Initially undetected lossofreactorcoolantinventory duringnaturalcirculation cooldown3.'dditional instrumentation requiredfornaturalcirculation cooldown.

~jeIEIE'I'*EIIf P$

FINDINGSANDCONCLUSIONS 1.Naturalcirculation decayheatremovalandsubsequent cooldownofthereactorcoolantsystemwereadequate.

2.Anomalous pressurizer levelbehavioroccurredafterseveralhoursintothecooldownwhenasteambubblewasformedinthereactorvesselhead.Thisresultedfromcoolingthepressurizer belowthetemperature oftheheadarea.3.Thereisnotemperature instrumentation inthereactorvesselheadarea.Suchinstrumentation couldalerttheoperatorofapproaching saturation conditions inthereactorvesselheadarea.4.Normalinstrumentation forreadingRCShotlegtemperature wasnotusableoncethesystemwascooledbelow515'F.5.Thesubcooling monitorinstrument isalsonotusablebelow515'Fsinceitrreceivesitshotlegtemperature inputfromanarrowrangeinstrument.

6.Althoughwiderangepressureindication wasavailable totheoperators, noautomatically recordedpressuretrendingwasavailable oncesystempressurewasbelow1500psi.Theoperators manuallyrecordedreactorcoolantpressures at30minuteintervals duringthecooldown.

7.AftertheshutdowncoolingsystemwasvalvedintotheRCSapproximately 10,000gallonsofreactorcoolantwasdrainedinadvertently totheRefueling WaterTankatarateofabout50gpm.8.Letdownsystemoperations continued foraperiodofaboutthreehoursafterthepressurizer levelanomalies started.9.Atthetimethesteambubblefirststartedtoformunderthereactorvesselhead,thereexistedinthereactorvesselatemperature difference ofabout200'Fbetweenthetopofthevesselflangeandthecoolantnozzles.Thiscondition isnotnormallyanalyzedaspartoftheASMESectionIIIanalysis.

10.Asinglemalfunction inthecoranonreactorcoolantpumpsealwatercoolingsystemledtotheshutdownofallfourreactorcoolantpumps.

11.Theini.tially unaccounted-for lossofreactorcoolantinventory, whichwasconcurrent withandmaskedbyabnormalpressurizer levelbehavior, mustbegivenseriousconsideration asitmayapplytoafutureeventwhereagreaterlossofinventory mayalsoinitially goundetected.

12.Formation ofasteambubbleunderthereactorvesselheadshouldbeavoidedthroughprocedural controlandoperatortraining.

However,operations duringcertainemergency conditions, e.g.,steamgenerator tuberuptureorreactorcoolantpumpsealfailure,mayleadtotheformation ofasteambubbleunderthehead.Maintenance ofsubcooling inthehotlegsisagoodindication ofadequatecoolantinventory andnaturalcirculation.

Shouldlossofsubcooling inthehotlegsoccurasaresultofcondensation ofthesteambubbleorthroughsimultaneous lossofcoolantinventory, thepost-TMItrainingandprocedures shouldensurethattheoperators willtakecorrective actionbyinitiating theemergency corecoolingsystems,restoring subcooling andcoolantinventory.

Naturalcirculation shouldnotbeimpairedasrestorations ofsubcooling willpreventvoidsfromaccumulating inthecoolantloops.

Eq'E4 APPENDIXSOESEQUENCEOFEVENTS*h1t.h0I.'IhlI1.1IEtI

SequenceofEventsSt.LucieJune11,1980J'Vg~Jr>~~"II-JPlantStatusPriortotheEvent:St.Luciewasoperating at99.6Xreactorpowerwithallthecontrolelementassemblies

'(CEA's)fullywithdrawn.

Fourreactorcoolantpumps(RCPs)wereoperating.

Theletdownandchargingsystemswereinservice.ReactorCoolantSystempressurewasapproximately 2250psiandaveragetemperature was563.4'F.Asteamleakinthepenetration roomjustoutsideofthecontainment buildingcausedafaultinasolenoidonapilotactuatedpneumatically operatedvalve.At2:26am,theplantexperienced thefailure(failedclosed)ofasingleComponent CoolingMater(CCW)returnheaderisolation valve.Thefailurecausedalossofcoolingcapability toallRCPs,soareactorpowerlevelreduction wasinitiated andthefollowing sequenceofeventsensued.(Ref.50,16,6,9,49)

J*CJM"JJ'ljV'JJ*.J~I'~-ILP&Time2:33am2:34am2:35am2:38amEventReactortripTurbine/Generator tripAuxilaryFeedwater pumpsAand8onSteamGenerator lAand1BlowlevelalarmsFeedwater pump18offFeedwater pump1AoffFeedwater pump18onReactorcoolantpump1B1offRCPs1A1,182and1A2offRCP181onRemarksandReferences Theoperatortrippedthereactor.'ystem responses werenormal.(Ref.6,8,7,16).'ctions weretakentocontrolsteamgenerator waterl,.evels.

ThestoppingoftheRCPsindicated thatactionswereunderwaytoplacethereactorcoolantsystem(RCS)innaturalcirculation.

Naturalcirculation isusedtoremovedecayheatfromthecorewhenRCPsareunavailable (Ref.6,16).Theseactionsalongwithbleedingsteamfromthesteamgenerators removeddecayheatfromtheRCSusingnaturalcirculation (Ref.6,16).Thecontinued rateofincreaseintheRCShot-legt'emperature promptedactionbytheoperatortoforceJ'Ir.SOE-1.

S Time2:39amRCP1B1offEventRemarksandReferences coolantwaterthroughthereactorcoretoremovedecayheat(Ref.6,13,14,15).ReturnedtocoolingoftheRCSusingnaturalcirculation (Ref.6,13,14,15).2:45am2:50am(approx.)

3:00am(approx.)

Vl3:12am3:50am3:54am4:00am4:35am4:45am4.45amFeedwater pump1BoffIndicated pressurizer levelreturnedtothecontrolsetpointlevelNaturalcirculation cooldowncomnenced Auxiliary feedpump1ConTheCCWflowpathwasrestoredtoallRCPs.Auxiliary feedpump1Coff.Commenced borationofRCSPressurizer lowpressuresafetyinjection actuation pretripsignalreceived.

Completed borationofRCSCoaeenced loweringsteamgenerator 1Blevelfrom63Kto20$Steamgenerator waterlevelswerecontrolled fromthistimeonbyusingAuxi'liary Feedwater pumps1Aand18(Ref.6,64,16).Changesinlooptemperatures, RCSpressure, andpressurizer levelfollowing theinitialtransient hadsteadied(Ref.63,55,57).Adecreasing trendinlooptemperatures withapproximately 20to25'FhTindicates thatacooldownoftheRCSusingnaturalcirculation wastakingplace(Ref.AppendixTH,55,57,16).Ref.6Ref.49,50Ref.-'6Ref.49,52RCSPressurehaddecreased toapproximately 1700psi.Thecoldlegtemperature wasindicating approximately 400'F.CooldownoftheRCSusingnaturalcirculation appearedtobenormal(Ref.6,57,1,55).Shut<(own boronconcentrations wereestablished intheRCS(Ref.49,52).Thisactionwastakenbytheoperators tomakeroominthesteamgenerators fortheadditionofacoldslugofSOE-2 XN TimeEventRemarksandReferences waterduringthelaterstagesofthecooldownprocess.Theadditionofcoldwateratthatpointisusedtospeedthecooldownprocesswhentheamountofsteamproducedbythe.heattransferfromtheRCStothesteamgenerators hasbeenreducedtolowvalues.Theselowvaluesslowthecooldownprocesswhenthetemperatures andpressures intheRCSareslightlyabovetheoperating temperature andpressurerequiredforshiftingcoolingfromthesteamgenerators toshutdowncoolingusingtheLPSIsystem(Ref.64).PlantStatusatAroximatel 4:55amThereactorwasshutdown.

Reactorcoolantpumpsintheloopswerestopped.Theindicated coldlegtemperature (380'F)andincoretemperatures (412-415'F) wereindicating acoolingtrend.RCSpressurewasapproximately 1450psi.Bothsteamgenerator waterlevelswerebeingmaintained atlevelstosupportanaturalcirculation cooldown.

Pressureinbothsteamgenerators indicated approximately 200psi.CCWhadbeenrestoredtothereactorcoolantpumps.5:00am(approx.)

5:40am(approx.)

6:00am6:13-6:15am(approx.)

Commenced loweringsteamgenerator 1ALevelfrom65to20$SteamGenerator 1BLevelreached20$Hainsteamisolation valves(MSIVs)closedMaincondenser vacuumbreakeropenRCSpressureindicates 1140psiIncoretemperatures indicateintherangeof349-352'F LoopTHindicated approximately 349fLoopTcindicated approximately 325'fPressurizer levelincreasing LoopTHindicates 346'FLoopTcindicates 320'FRefdrence 4:45amEntry.WiththeMSIVsclosedandvacuumbroken(pressure atatmospheric valuesinthecondenser),

heattransferfromthesteamgenerators tothemaincondenser wasstopped.Pressureinbothgenerators indicated approximately 100psi.Steamdischarge fromthesteamgenerators wasdir'ected tothe'tmosphere throughtheatmospheric dumpvalves.(Ref.6,16,48,64).Indications atthistimeshowthatcooldownusingnaturalcirculation wasproceeding asanticipated (Ref.1,16,57,55).Auxiliary sprayintothepressurizer wasusedtodecreasetheRCSpressure(1140to690psi)from06:00through06:30.Thisactioncausedtheformation ofasteambubbleSOE-3 jJC4II1,(

-TimeEventRemarksandReferences 6:20am(approx.)

6:35am6:40am7.00am8:45am(approx.)

9:40am(approx.)

10:00am(approx.)

Incoretemperatures indicateintherangeof342'Fto344'FSteamGenerator 1Alevelreached20$LPSIpumps1Aand1BonPressurizer levelincreased significantly LoopTHindicates 325'FLoopTcindicates 305'FPressurizer pressureindicates 500psiIncoretemperatures indicateintherangeof325'Fto327'FSteamGenerator 1Aand1Blevelsincreasing SteamGenerator lAand1Blevelsreach65%Letdownisolatedunderthereactorvesselhead,andresultedinanunexpected pressurizer levelincrease(Ref.63,1,16,55,57).AppendixTHRefertothe05:00and05:40entries(Ref.64).LPSIpumpswereplacedinrecirculation towarmuptheShutdownCoolingSystempipinginpreparation forshutdowncoolingusingtheLPSIsystem(Ref.54,6).Thelevelchange(465to965)andtherateoflevelincreasechangedsignificantly fromapproximately 06:40through7:05am(Ref.63).Plantparameters indicatethatcooldownusingnaturalcirculation wascontinuing, uninterrupted bythesteambubbleinthereactorvesselhead(Ref.6,55,57,16,1).Indicated levelsinthe1Aand1Bsteamgenerators wereapproximately 27Koftheoperating range.Indicated pressureipsteamgenerator 1Aand1Bwas<75psi.Fillingthegenerat'ors withcoldfeedwater aidsincoolingdowntheprimarysystemtoatemperature compatible withinitiating shutdowncoolingusingtheLowPressureSafetyInjection System.(Refertothe5:00amand5:40amentries.Ref.64,48).'.'ef.64jAnomalies inpressurizer levelresponsewerecontinuing.

Itwasreportedthatlevelroserapidlywhenauxiliary sprayfromthechargingpumpswasdirectedtothepressurizer followedbyarapiddecreaseinlevelwhenchargingwasdirectedtotheloops.Theletdownsystemwasisolatedbytheoperators topreventdrainingofreactorSOE-4 Time10:06amEventLPSIpumps1Aand18offRemarksandReferences coolantfromthereactorcoolantsystem.Althoughthiswasthefirstloggedisolation, theoperators.

reportedthatletdownwasshutoffbetween8:15amand8:55am.(Ref.69,16,63,9).MarmupoftheLPSIsystemwascomplete.

Valvealignment wasstartedtoaligntheLPSIsystemforshutdowncooling(Ref.6,59).10:10amAuxiliary.

Feedwater pump1Aoff10:28amLPSIsystemlined-uptotheRCS(approx.)

Oneofthetworunningauxiliary feedwater pumps(1A&1B)wasstopped.Capacitytomeetsteamgenerator levelrequirements wasmaintained withonepump(Ref.6).LPSIsystempressureindicated 235psiwhileRCSpressureindicated 235psi.LoopTHindicated 290'FwhileLoopTcindicated 275'F.(Ref.59,55,57,1).10:33am10:34am10:37am10:51amll:00am(approx.)

ll:07am(approx.)

LPSIpump1BonLPSIpump1BoffPressur'izer pressure-230psiHotLegTemperature

-289'FColdLegTemperature

-273'FLPSIpump1BonFlowindicated intheLPSIsystemShutdowncoolingestablished usingtheLPSIsystemLPSIpumpdischarge pressurespikedtoavalueinexcessof400psi.Itwasreportedthatthedischarge reliefvalveliftedresulting inthesubsequent stoppingoftheLPSIpump1B(Ref.59,6,16,54,69).Reference 10:33entry(Ref.6).The'parameters listedweremanuallyrecordedinthecontrolroomlog.(Ref.49).Toestablish shutdowncoolingofthereactorcoolantsystemusingtheLPSIsystem(Ref.54,59,6).Ref.59,54.Ref.49SOE-5 Time11:27amEventAuxiliary Feedwater pump18stoppedRemarksandReferences AsheatremovaloftheRCShadbeenestablished usingtheLPSIsystem,heatremovalthroughthesteamgenerators was'olongerrequired(Ref.6,8).I/'+11:35am-12:23pm(approx.)

Indicated LPSIsystempressuredecreasing LPSIsystempressurewassteadilydecreasing fromthepressureindicated atstart-up(255psi)toanindicated lowvalueof150psiat12:26pm.Anomalous pressurizer levelresponsewascontinuing inresponsetoshiftingthechargingwaterentrypointintotheRCS.(Referto10:00amentry).Subsequent analysisofpressurizer levelresponses duringthisperiodfrom10:28amindicatealossofRCSwaterinventory.

Temperatures throughthisperiodremainedrelatively constant.

Incoretemperatures indicated 281'F,LoopT>indicated

~276'FwiththeLoopTcindicating 275'F(Ref.59,63,16,55,57).F("\~II-TJ12:26pm12:27p01','-,.'12:23pmTI'JlLPSIpumplAonLPSIpumplAoffLPSIpump1AonLPSIpump1BoffAmarkedincreaseinLPSIsystemflowandpressureindicated theadditionofinventory totheRCSfromtheRefueling MaterTank(Ref.54,59,6)AppendixRAD.Ref.6,54,59.Pressurizer levelresponseindicated thattheRCSsysteminventory wasbeingreplaced(Ref.6,59;54).F12:30pm12:34pmSubcooled conditions werereachedinthepressurizer LPSIpump18onRef.1TShutdowncoolingusingtheLPSIsystemwasre-established.

PressureintheLPSIsystemwasincreased to260psiwiththetwoLPSIpumpsrunning,1ALPSIpumphadsuppliedtheinventory andpressureneededintheRCSwhile",.the1BLPSIpumpandheatexchangers providedcoolingintheRCS.(Ref.54,59,16,6,55,57,1).FSOE-6

Time12:34pm(approx.)

EventRecordedpressurizer levelindication wentoffscaleonthehighend.Ref.63.RemarksandReferences foalI1:30pm1:57pm2:50pm(approx.)

3:45pm(approx.)

4:20pmSaturated conditons wererestoredinthepressurizer LPSIpumplAoffRecordedPressurizer Levelindication returnedtotheindicating rangedisplaying adownwardtrendThedownwardtrendindicated onthe.recordedpressurizer levelinstrumentation wasstoppedatanindicated levelof581RCSdegasification procedure wascommenced Thewaterinthepressurizer hadbeenheatedtosaturated conditions throughtheuseofpressurizer heaters.(Ref.1).Thefollowing plantconditions were*recorded:

PressureintheLPSIsystemwasindicating 385psiataflowrateof3300gpm.LoopTHwasindicating 220'F,LoopTcwas<<205'F,withincoretemperature of<<225'F.Pressurizer pressurewasrecordedat260psiatatemperature of410'Fwhichrepresent saturated conditions inthepressurizer (Ref.6,1,59,54,55,57,16).LedownfromtheRCShadbeenestablished ataflowrategreaterthantheflowrateofthechargingpumps.Thisactionwastakentogetpressurizer levelinitsnormalrecordedrange.(Ref.63,16).ChargingintotheRCSloopsusingtwochargingpumpswasinitiated.

Pressurizer levelindication responded withanupwardtrend.Thistrendisanticipated whentheRCSisfullofwaterwithabubbleintheupperportionofthepressurizer.

Priortothistime,chargingintotheloopsbroughtadecreas'ing pressurizer levelindication signaling thatsteamexistedatsomeotherlocationintheRCSinadditiontothesteaminthepressurizer.

(Ref.63,11).Ref.50Plantstatus:TheplanthadbeenshutdownandwasbeingcooledusingtheLPSIsystemintheshutdowncoolingmodeofoperation..

SOE-7 l.V4I(Q APPENDIXT/KNATURALCIRCULATION ANDPLANTCOOLDOWN 1lpl 0APPENDIXT/HNATURALCIRCULATION ANDPLANTCOOLDOWNThereactorwasmanuallytrippedat2:33am.Allreactorcoolantpumpsweretrippedby2:35am.The181reactorcoolantpumpwasrestarted at2:38am,and.wasrunforaboutoneminute,thenstopped.Allreactorcoolantpumpsremainedstoppedtoeliminate anyriskofpumpsealfailurefromoperation withoutsealwatercooling.Pumpoperation wasnotresumedevenaftercoolingwaterhadbeenrestored, aboutl-l/2hoursafterithadbeenlost.-Thereactorcoolantpumpsweremanufactured byByronJacksonandhaveathreestagemechanical sealplusavaporseal.Sealwaterissuppliedonlyfromthereactorcoolantsystem,thewaterfirstbeingcooledbyaheatexchanger integralwiththepumps.Itwasreportedthatthesealsdidnotexperience greatly.increased leakageduringtheplantcooldown.

However,intermittent RCPsealalarmsrecurredthroughout thecooldown.

NaturalCirculation Naturalcirculation ofreactorcoolantandcontinued heattransferfromthereactorsystemtothesteamgenerators occursasaconsequence ofthehigher~~elevation ofthesteamgenerator relativetothereactor.Atemperature differential betweenthehotlegsandcoldlegsofthesystemisrequiredtosustainnaturalcirculation.

Thecoolantflowcanbeestimated bycomparing themeasuredtemperature differential tothefullpowertemperature differential, knowingthedecayheatatanygiventimeaftertrip.Naturalcirculation coolingworkedwellthroughout thecooldownusingthesteamgenerators.

Temperature differentials betweenThotandTcoldrangedfrom20-40'F(FiguresT/H-Iand2),comparedwith44'Fduringpoweroperation.

Withcorepowerinthe1-2Xrange,thetemperature differential corresponded toareactorcoolantflowrateof2-3goffullflow.Thehighercoolantflowrateundernaturalcirculation occurredsoonafterreactortrip,corresponding tothehigherdecayheatproduction.

Atabout7:00am,duringthetimethatevidenceofthefirstdrawingofthesteambubbleunderthereactorheadappeared, thetemperature difference betweenThotandTcoldwasabout20'F.Withdecayheatjustunder1$,thecoolantflowrateisestimated tohavebeenT/H-IAPPENDIXT/H near2Xoffullflow.Throughout thetimethatthesteamgenerators wereusedtocooltheunitwithasteambubbleunderthehead,thecoolanttemperatures indicated thatabout2Xofratedflowwasbeingmaintained.

Aftershutdowncoolingwasinitiated atabout11:00am,thesteamgenerators con-tinuedtobefunctional forafewhours,assisting intheremovalofheatfromthereactorcoolantsystem.Fromthetimeofreactortripuntilinitiation ofshutdowncooling(2:33am-11:00am),thecoo'antsubcooling rangedfrom67'Fatthemomentoftriptoashighas225'Fat5:30am,basedonthehighestcoreexitthermocouple readingorThotinstrumentation locatedinthehotlegs.TheThotinstrumentation reachedthelowendofitsrange(515'F)at3:20amandwasnotusefulforabout2-1/2hours,untilithadbeenre-ranged byanISCtechnician.

Below515'F,thecoreexit.thermocouples wereusedtoindicatetheamountofcoolantsubcooling.

From5:30am,coolantsubcooling fellslowly,reachingalowof55'Fat12:23pm,justpriortoraisingcoolantinventory andpressurethroughoperation ofLowPressureSafetyVInjection (LPSI)pump1Ainthesafetyinjection mode.AtnotimedidtheThotinstrumentation indicateatransferofhotwaterfromthereactorvesselheadregionintothehotlegsasthesteambubbleformed.However,flowfromtheuppervesselandheadregionintothehotlegseachtimethesteambubbleformedwasalwaysasmallfractionofcoolantflowthoughthecoreandloops.Betweenll:05amandll:25amhotwaterflowingfromthepressurizer duringarelatively lowwaterleveldipwasindicated bytheThotinstrumentation whichbythattimewasbeingrecorded(Ref.55).SteamFormation durinCooldownCooldownonnaturalcirculation, byfeedingthesteamgenerators anddumpingsteamtothecondenser, beganatabout3:00am.Naturalcirculation ofreactorcoolanthadbeenwe'lestablished bythetimethecooldownstarted.Thecooldownpro-gressedatanaverage60'Fperhouruntilabout6:00am.Shortlyafterthat,anattemptwasmadetocoolthepressurizer andreducepressurethroughtheuseofauxiliary sprayfromthechargingpumps.Between6:15amand7:15amthewaterlevelinthepressurizer roseunexpectedly, muchmorethancouldbeexplained bythevolumeofwaterbeingpumpedintothereactorcoolant=system (FigureT/H-3).Thepressureat6:15am,whenthesteambubbleapparently firststartedtoformundertheheadofthereactorvessel,wassomewhere between1140and690psig,theAT/H-2APPfNOIXT/H

'l~pressurelogentriesat6:00amand6:30amrespectively (FigureT/H-4).Satura-tiontemperature at6:15am.corresponding tothemeanpressurebetween6:00amand6:30amwas535'F,likelyverynearlythetemperature ofthereactorvesselhead~anditscontentsatthebeginning ofbubbleformation.

Thecoldlegtemperature was320'Fatthistime,soatemperature differential ofabout200'Fexistedinthereactorvesselbetweenthetopoftheflangeandthecoolantnozzles.Fromtheobservedlevelriseinthepressurizer, thecoolantshrinkage fromcooling,andestimated chargingandletdown,thesizeofthefirststeambubbleexpansion isestimated tohavebeensomewhatlargerthantheheadvolumedowntotheclosureflange,butwellshortofthehotlegnozzle(FigureT/H-5).IItisnotpossibletoestimatereliablytheinventory ofreactorcoolantduringthecooldownsincethechargingflowindicator wasoutofservice,startingandstoppingofthechargingpumpsmaynothavebeennotedalways,(theoperator's writtenlogshadnoentriesonchargingpumpoperation) andtheletdownflowwasvariableandnotrecorded.

However,fromthehourlylogentries,itappearstheletdownflow,inresponsetotherapidlyrisingpressurizer level,mayhavebeenslightlyhigherthanchargingflow(auxiliary spray)duringthedrawingoftheinitialsteambubble.Aslowlossofinventory apparently continued inresponsetohigherthandesiredpressurizer leveluntil8:15am,whenletdownwasreported~~tohavebeenstoppedfor40minutes.Asmanyas3chargingpumpsmayhavebeenoperatedforseveralminutesduringthisinterval, affording anincreaseincoolantinventory.

At9:00am,chargingwasevidently backtotheflowofonepump(about44gpm),andletdownflowwas30gpm.Thechargingflowappearedtohavecontinued at44gpmpast3:00pmLetdownflowwasstoppedshortlyafter10:00am,remaining offuntilsometimebetween2:00pmand3:00pm,whenitwasre-initiated atabout80gpm.'Between9:00amand12:30pmthechargingflowwas;alternated severaltimesbetweenthereactorloopsandpressurizer auxiliary spray,causingrapidpressurizer leveltransients, asthesteambubblesinthepressurizer andthereactorheadalternately swelledandshrankinoppositedirections.

(Fig.T/H-3)CoolantFlowtoRefuelinWaterTankAt10:28amtheisolation valvesbetweenthereactorcoolantsystemandtheshut-downcoolingloop18(LPSI-18) wereopened,inordertostartshutdowncooling.Pressurizer pressurewasindicating 235psi.Itwasreportedthatthesuctionreliefvalveontheshutdowncoolingloopliftedatthistime,andthedischarge reliefvalveliftedat10:33amuponstartingtheLowPressureSafetyInjection T/H-3APPENDIXT/H2~

gjjP+~gQa+~

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-,4ikp.i4>~'ci$4~<<'~~@+~~w+s wt,>'>wbtky'8+~+0'i pi;j'py'~~'gy++ie4q'o'Wb'0 e>e<ieq$~;aij(g+Lgjk~~je~~i~.

gj4b)i,gk+i)'LPSI)pump1B.TheLPSIpump1Bwasthenstopped,andinitiation ofshutdowncoolingdelayeduntilsystempressuredecayedanother20psi.:j)~II"t[ILe)Uponopeningthevalvestotheshutdowncoolingloopat10:28am,thepressurizer leveltransient, whichwasthentrendingdown,exhibited adistinctly different responsethanthepreviousdownwardmovements (FigureT/M-3).Whereasthepre-vioustwodownwardlegsofthepressurizer leveltransient indicated anexponen-tialdecayofthesteambubbleunderthehead,oncetheshutdowncoolingloopisolation valveswereopened,steeplyfallinglevelswereexperienced eachtimethechargingflowwasswitchedfrompressurizer spraytoreactorloopinjection.

Sinceletdownhadbeenshutoffshortlyafter10:00am,andreactorcoolantaver-agetemperature wasnearlyconstantfrom9:30amuntilnoon,asteadilyrisingreactorinventory resulting fromthechargingflowwouldhavebeenexpected.

However,agenerally downwardpressurizer waterleveltrendwasexperienced.

Analysisofthepressurizer levelandsysteminventory indicatethatareactorrcoolantleakwasinprogress.

FurtherevidenceofthisleakappearedontheRefueling WaterTanklevelstripchartrecording (Reference 26).FromtheRWTstripchart,theleakappearstohavebeenabout5000;gal-:upto12:23pm;.Averagedoverthetimeperiodfrom10:28amto12:23pm,theleakratewouldhavebeenabout45gpm.Howevercalculation ofcoolantinventory overthattimeperiodbasedonpressurizer levelresponse, assumingletdownshutoff,chargingin-flowfromonepump(44gpm)and'reactor coolantpumpsealout-flowof4gpm,givesanestimated leakflowofabout60gpm.ThenetlossfromtheReactorCoolantSystemwassomewhere intherangeof5-20gpm..Evidently thetransferofreactorcoolanttotheRefueling WaterTankoccurredthroughapartially openvalveintherecir-culationlinefromLPSIpump1B.Theorificeinthislineisratedat50gpmat..pumpshutoffhead(200psi).LeakageofreactorcoolanttotheRefueling.

WaterTankisdiscussed furtherinAppendixRAD.Ae<f~~Soq~)~~vr~~Notingthatpressurizer pressurehaddecreased to115psiandpressurizer water,<<'evelhadrepeatedly droppedbelowthereference value,LowPressureSafetyInjection Pump1A,whichhadbeenalignedforsafetyinjection, wasstartedat12:23pminordertoincreasepressure.

LPSIpump1Bwasturnedoffforseveralminuteswhilepump1Awasinjecting, loweringthepressureinthecommonLPSIpumpdischarge header,thuspermitting LPSIpump1Atoraisereactorpressuretothepumpshutoffhead,about200psi.About5000gallonsofrefueling waterwaspumpedintothereactorsystembetween12:23pmand12:34pm,atwhichtimeLPSIpump1Bwasre-started, raisingthedischarge headerpressurewellabovetheshutoffheadofthelApump.T/H-4APPENDIXT/H

~~r-mmAt12:23pm,justpriortostartingLPSIpumpIAtoinjectwate~intothereactor,thesteambubbleundertheheadhadbeenallowedtodecaytoasmall,butunknownsize,whilewaterflowedfromthepressurizer toreplacethedecayingbubble.From"tough coolantinventory calculations, thesteambubbleisestimated tohavebeennolargerthanafewhundredcubicfeetatthattime.Operation ofLPSIpumplA,injecting waterandraisingpressurewouldhavereducedthebubblesizebyhalf.Completecollapseofthesteambubble.inthereactorvesselheadisesti-matedtohaveoccurredwithinminutesoftherepressurization..

I*rm;,'.-.Oncethepressurizer waterlevel(FigureT/H-3)hadbeenraisedabove1001.(indi-cated)onthehotcalibrated levelrecorderat12:34pm(above67',corrected for,temperature),

thepressurizer steamspacewascompressed, andthewaterinthepressurizer wasthensubcooled.

Thepressurizer heaterswereenergized toraisethewatertemperature, sothatthepressurizer couldbeusedtomaintainpressureabove200psi.Theheatershadraisedthetemperature ofthewatertosaturation at175psi.by1:15pmandcontinued toraisepressure, reaching260psiby2:00pm.Pressurewasthenmaintained near260psiforseveralhours,preventing anyreappearance ofasteambubbleunderthereactorvesselhead.'tX*mAfterthereactorinventory andpressurehadbeenincreased throughoperation ofrLPSIpumplAat12:34pm,andshutdowncoolinghadresumedusingLPSIpump1B,thelApumpcontinued tooperateintheinjection mode.The1Apumpwasmerelyrecir-culatingwaterbacktotheRefueling WaterTankthroughitsminiflowrecirculation line,'asthepressureinthedischarge headerwastoohightopermitfurtherinjection tothereactorcoolantsystem.LeakagefromtheshutdowncoolingsystemtotheRefueling WaterTankcontinued until1:57pmatwhichtimethelApumpwasstoppedandtherecirculation linesfrombothpumpswereisolatedfromtheRefueling WaterTank.From12:34paluntil1:57pm,itisestimated thatapproxi-~mately5000gallonsofreactorcoolantleakedtotheRefueling WaterTank.Duringthistimeperiodtheletdownwassecured,andmostlikelyonechargingpumpwasoperatedcontinuously.

Thenetrateoflossfromthereactorsystemisestimated tohavebeen20gpm.rrBy2:00pmthepressurizer hadbeenheatedsufficiently torestorethereactorcoolantpressureto260psi,andtheslowcoolantleakhadbeenstopped.The'oolantinventory wasnowslowlyincreasing fromcontinuous chargingflow.Itwasmreportedthatat2:32pmletdownflowwasre-initiated atabout'twice thechargingflowrate.Thepressurizer steamspaceexpandedslowly,bringingthewaterlevelrT/H-5,,APPENDIXT/Hr

'aindication backonscaleontherecorder(hotcalibrated channe'l, FigureT/H-3)by2:50pm.Atabout3:45pmchargingwasincreased toahigherflowratethanlet-down,andthepressurizer waterlevelexhibited anormalslowriseinresponseovera45minuteperiod.Conditions hadbeenrestoredtonormal.4The1977NaturalCirculation CooldownilDuring1977,theSt.Lucieplantconducted acooldownundernaturalcirculation conditions..

Thepossibility thatasteamvoidhadbeenformedunderthereactor,'.-',<'.-.,"','-,'",-

vesselheadduringthateventhadnotbeenrecognized.

Thepressurizer water'eveltransient duringthatcooldownhasnowbeenexamined(FigureT/H-5),andanomalous behaviorsimilartotherecenttransient hasbeenconfirmed.

Thecool-downpriortothetimeofthefirstriseinpressurizer levelwasabout2hourslongerin1977thanin1980.Additional trainingand.understanding, whichcameasaresultoftheTHIaccident, enabledoperations personnel torec'ognize thesignificance ofthepressurizer lev'elbehaviorin1980.The1977transient pressurizer waterlevelresponse.

did.notexhibitanyevidenceofalossofcoolantinventory duringtheevent.Shutdowncoolingwasnotiniti-ateduntilapproximately 7-1/2hoursafterthefirstsharprisein,pressurizer level,comparedwith4hourstoinitiation ofshutdowncoolingin1980.Delayingthereduction ofreactorsystempressuretopermitinitiation ofshutdowncoolinggavethereactorvesselheadanditscontentsmoretimetocool,lessening thetendencytoformalargesteambubble.InventorControlProcedure Ananalysisofplantbehaviorduringthetimeperiodbetween8:00amand9:00amsuggestsaprocedure thatcouldbeusedtodetermine inventory ofreactorcoolantifalternate drawingofavesselbubbleandcollapsing ofitisdetermined tobeanacceptable operating methodforcoolingthereactorvesselheadarea.duringanaturalcirculation cooldown.

Duringthisperiodoftimechargingflowwasdirectedtothereactorcoolantloopandthepressurizer levelfell.By8:30amthesteambubbleintheheadhadvirtually collapsed, asevidenced bypressurizer levelwhichhadbottomedout,turnedaround,andwasrisingatarateconsistent withchargingandletdownflows.Atthistime(Fig.T/H-3)pressurizer levelproperlycompensated fortemperature, wouldhavebeenagoodindicator ofcoolantinventory.

Notehowtheroundedoffcharacter ofpressurizer levelturningaroundandstartingtorisewasdifferent fromtherestofthecurve,wheretheheadbubblewasnotfullycollapsed andtheturnaround oflevelindication waschar-3avT/H>>6,-'.;-'..;-';-'",.APPENDIX T/H,.-.~,.r.v.~..-,;"'-".Qc",>.!

acteristically asharpsawtoothshape.Theselaterwaterlevelturnarounds (causedbysprayingthepressurizer) exhibited ratesoflevelrisemuchfasterthanthatconsistent withchargingandletdownflows.'rom8:30amuntil9am,pressurizer levelwasagoodindicator ofcoolantinventory.

Pressurizer leveldidnotproperlyindicatecoolantinventory againuntilshortlyafter12:34pm,whenitisestimated thatthereactorvesselsteambubblefinallycollapsed.

Itwouldbepractical foroperators conducting anaturalcirculation cooldowntorepeatperiodically theprocedure whichwasusedbytheSt.Lucieoperators atabout8:30am,inordertoobtaincorrectindication ofcoolantinventory.

Theessential ruletofollowtoprovideproperindication istocausethepressurizer waterleveltransient tobottomoutandstarttoriseslowlywhilecontinuing tochargetothecoolantloop.T/H-7APPENDIXT/H

h~Et,,*~iJk'J"~Tnpat0233ThotandTcotdnaturalcirculation St.Lucia,6-11~4I-ReactorcoolanThottpumpoperatedThotlflstfument offscaleg520lTripat0233Tcotd0510'15202530354045505560TimeAfterTrip(minutes) 2:432:533:033:133:233:33TimeofDay(a.m.)FigureT/H-1.ReactorCoolantTemperatures FirstHourAfterTrip Naturalcirculation cooldownatSt.Lucie6-11-804$-350aE~300~T><<(fromcoreexitthermocouples) 250TcoidLoopBLoopA~5671011TimeAtterTnp(hours)3:334:335:336:337:33;8:339:3310:3311:33~12:331:33TimeofDaya.m.Ip.m.FigureT/H-2.ReactoroolantTemperatures DuringCoofdown 10070401004a.m.6a.m.8a.m.10a.m.12p.m.2p.m.FigureT/H-3.Pressurizer Level(hotcalibrated)

St.Lucio6-11-80' 0-22002100IIIIOperating rangepressurerecorder, reference 62II17001600~1500~1400g1300~1200c'100o10000900ca800700IIIIllimitofpILowerIIIIylIIIIIIIIressureIrecorderIIIIReference 1shutdownlog,widerangepressureindicator I<I'LIIBetween12:00noonand12:30,reactorpressure,.estimated fromshutdown.

coolingsystempressure-recorder IIII10000123456789101112TimeAfterTrip(hours)2:333:334:33,5:336:33?:338:339:3310:3311:33I12:331:332:33TimeofDaya.m.Ip.m.FigureT/HA.ReactorPressure rCEDMnozzleInstrumentation

~nozzleSteamvoid4Ifp~OutletnozzleUpperguidestructure Inletnozzle"ActivecorelengthFuelassemblyFigureT/H%.Estimated SizeofinitialSteamBubble 706030201000123456-'8910111213TimeAfterTrip(hours)FigureT/H4.Pressurizer Level,1977St.LucieNaturalCirculation Cootdown L

4APPENDIXRADKID'h-I'.*.~I'IIIRADIOCHEMISTRY ANDRADIOACTIVE EFFLUENTS FIIIp44"I4IT1'lI4FK44"44IIFkDF'IIF4IFlfII-I"IllIfpKK APPENDIXRADRADIOCHEMISTRY ANDRADIOACTIVE EFFLUENTS At-10:28amon6/ll/80,afterpreviously heatingupthewaterintheshutdowncoolinglines,shutdowncoolingloop1Bisolation valvestothereactorcoolantsystemwereopenedinpreparation forinitiating shutdowncoolingusingthe1Blowpressuresafetyinjection (LPSI)pump.AgradualincreaseintheRefueling WaterTank(RWT)levelbeganatthistime.Themostprobablepathwaythatreactorcool-anttooktoreachtherefueling watertankwasthroughthe1BLPSIpumpmini-flow recirculation valve(V-3205)whichmayhavebeenatleastpartially openwhilethesystemwasoperating intheshutdowncoolingmode.(SeeFigureRAD-1).Thisallowedthetransferofapproximately 5000gallonsofreactorcoolanttotherefueling watertankbetween10:28amand12:23pmatwhichtimethe1ALPSIpumpwasturnedontofillthereactorcoolantsystemandrepressurize backto200psi.About5000gallonsofrefueling waterwastranferred backtothereactorcoolantsystematthistime.The1BLPSIpumpwasturnedoffat12:27pmandrestarted at12:34pmandleftonthereafter intheshutdowncoolingmode.The1BLPSIpumpmini-flow recirculation valve(V-3205)r'emained open'uring thistimeallowingthecontinued transferofanadditional 5600gallonsofreactorcoolanttotherefueling watertankuntil1:57pmwhenallmini-flow wasisolatedusingthemotoroperatedvalvesontheLPSIpumpsmini-flow headeroutletline(V-3659andV-3660).Althoughthe1ALPSIpumpremainedinoperation until1:57pm,itsheadwassufficient topumpwaterfromtherefueling waterstoragetanktothereactorcoolantsystemonlywhenthepressureinthepumpdischarge linewasbelow200psi.Oncereactorpressurehadbeenrestoredto200psi(-12:30pm)andthe1BLPSIpumprestarted (12:34pm),pressureinthecommondischarge linewastoohightopermitfurtherreturnofcoolantfromtherefueling watertanktothereactor.Samplesofthereactorcoolanttakeninthisperiod(1:45pmon6/11/80)contained specificactivitylevelsofapproximately 10x102microcuries/ml.

Thetransferofatotalof10,000gallonsofreactorcoolantcontaining specificactivityof10x10microcuries/ml totherefueling watertankrepresents theinadvertent transferofapproximately 3.8curiesofactivityfromthereactorcoolantsystemtotherefueling watertank.Plantventgaseous,particulate andiodineactivitylevelsremainedsteadybeforeandthroughout thetransient withplantventgaseousactivitymaintaining approxi-RAD-1APPENDIXRAD mately200-300countsperminute.Subsequent to6/11/80,FloridaPower&Lightconducted acontainment purgeandthreereleasesfromthegasdecaytanksalsowithoutanyabnormalreleasesofactivity.

Theremayhavebeenasmalloff-sitereleaseofgaseousradioactive materialfromtherefueling watertankexternalventduetothetransferofreactorcoolanttotherefueling watertank.Areactorcoolantsampletakenat1pmon6/ll/80contained noblegaseousactivityof1.35x10microcuries/ml.

Isotopicanalysisofthissampleshowedthisgaseousactivitytobecomposedofgreaterthan9(CXe-.133,8$Xe-135withtheremainder (lessthan2X)Kr-85.Ifasmuchas10,000gallonsofreactorcoolanthadbeentransferred totherefueling watertankthiswouldhaveresultedinthetransferof0.51curiesofnoblegasactivity.

Theallowable environmental limitforunplanned oruncontrolled releaseofnoblegasisapproximately tentimesthisamount.Asmallfractionofthe0.51curiesofnoblegasactuallytransferred totherefueling watertankwouldbeexpectedtohaveoutgassed fromtherelatively coolrefueling watertankpriortothedecayofthexenonfractioninthetanktonon-volatilecesium.RAD-2APPENDIXRAD RWT4IV3659MMostprobablereactor~coolant)eakpathLoop1ALoop1B"A"LPSIpumpShutdowncoolinglinesV.3204~IA44Miniflowrecirculator V-3205fl4B4~Miniflowrecirculator AirsupplyV.3484LOOP1A2Loop1A1"8"LPSlpumpFigureRAO-1.V-3400Loop1BlLoop1B2 S,

APPENDIXOPSPLANTPROCEDURES ANDOPERATION

APPENDIXOPSPLANTPROCEDURES ANDOPERATION

1.0 Objective

'elevantplantprocedures ineffectatthetimeofthecooldownwerereviewedto.,iascert'ain iftheywereadequateandproperlyappliedinplacingtheplantina.shutdown andcooledcondition.

Procedure revisions madeafterthecooldownwerealsoreviewed.

P~',IJ2.0~ScoeThescopeofthisreviewcoveredthefollowing:

Emergency operating procedures, Off-normal operating procedures, sequenceofevents,operator-logs,relateddrawings, anddiscussions withvariousFPSLpersonnel.

30Discussion FPBLhadthreemajorprocedures thatwerewillbecoranented oninthisappendix:

1.Off-normal Operating Procedure-

  • ".2.Emergency Operating Procedure 3.Operating Procedure appliedduring"'this transient andthat'eactor CoolantPumpLossofReactorCoolantPumpFlow/Natural Circulation Reactor.PlantCooldown-Hot StandbytoColdShutdown.

Off-normal 0eratinProcedure

-ReactorCoolantPumTheapplicable sectionofthisprocedure

'addresses theactiontotakeifthealarm"ReactorCoolantPumpLowCoolingWaterFlow"occursonallReactorCoolantPumpsatthesametime.Itstatesthatifcomponent coolingwatercannotbeestablished within10minutes,tripthereactor,turbine,andallfourreactorcoolantpumps.Also,itdiscusses amethodforreopening thesupplyandreturnheadervalvestothereactorcoolantpumps,ifanyofthesehavefailed.Inthisevent,oneofthereturnheadervalves(HCV-14-6) failedclosed.(SeeFigureOPS-1).Reopening ofthisfailedvalvetookapproximately 11/2hours.Theprocedure wasfollowedwhichtrippedthereactor,turbine'andallfourreactorcoolantpumps.Plantresponses tothiseventindicatethatoperators tookactionseilOPS-I;;,"",';"*'PPENDIX'PS

~,

/*l'r'lprescribed bytheprocedure, andtheprocedure wasadequateforplacingtheplantintoahotstandbycondition.

Sincethe6/28/80cooldown, FP&Lhasprovidedquickconnectfittingstothesefourvalvesandanitrogensupplywhichwouldallowthemtobereopenedmorequicklyintheeventofanelectrical orpneumatic failure.Thosedesignchangeshavebeenreflected inarevisedreactorcoolantpumpoff-normal operating procedure.

rIEmerenc0eratinProcedure

-LossofReactorCoolantPumFlow/Natural Circulation.

'Theprocedure hadanintroductory discussion ofnaturalcirculation including var-ioussourcesthatcanbeusedtodetermine subcooling margin.Itspecifies appro-priatesteamgenerator levels(65$),operation ofthesteamdumps,anadministra-tivecooldownrate(max.75'/hr),subcooling margin(>20'F),maintenance ofplantpressure, loophT(<fullpower)andTHandTcresponse.

Italsoreferences aprocedure tocontinueplantcooldowntocoldshutdownifthereactorcoolantpumpscannotberestarted withinafewminutes.Astepinthisnaturalcirculation procedure specifies thatanI&Ctechnician willinstallwiderangeThotforaDigitalDataProcessing System(DDPS)displayonthecontrolpaneltoallowcontinued monitoring ofTH.Thencrmalindicator/recorder rforTHisnarrowrangeanddoesnotreadbelow515'F.Also,thesameThotnarrowrangetemperature transmitter inputsthesubcooling meter,resulting inaninvalidreadingfromthesubcooling monitorwhenThotisbelow515'F.Consequently, theoperatormustconsultthesteamtableswhenTHisbelow515'Ftodetermine sub-coolingmargin.Plantresponses indicated thattheprocedure wasfollowedandwasadequatetoestablish andmaintainnaturalcirculation whileinahotstandbycon-dition.t)',//,~+..'r,"'-5'"gr/r,",~,g~.l~.'ll;'tg~,]ll/~r"/"r~/l0eratinProcedure

-ReactorPlantCooldownHotStandbtoColdShutdownThisprocedure providesinstructions forthecooldownoftheReactorCoolantSystem(RCS)fromahotstandbytoacoldshutdowncondition.

Theseinstructions includecooldownratesfortheRCS((75'/hr.)

andpressurizer (c190'/hr.).

Temperature differential limitsareprovidedbetweenpressurizer waterphasetem-peratureandpressurizer spraywatertemperature (350'F).TheRCStemperature andcorresponding allowable pressurerelationships aredetermined throughtheuseofafigure.Theprocedure alsodirectstheoperators inplacingvarioussafetyandRCSsupportsystemsinashutdownorstandbycondition.

Additionally theseproce-r.'lOPS-2.',.;.APPENDIXOPS1l"Il!r'p/V~,+r//~/-g,~p-~,rr~rr r~p

,~.i'"$$+g~~wQo'.'

'.g+.p('g~fp;

~lpga<<,M~l p."0',,~>~<<Ip'...~-',te.I'Iduresdetailactionstotakewhensequentially stoppingReactorCoolantPumps(RCPs).Finally,instructions areprovidedforplacingtheLowPressureSafetyInjection System(LPSI)inoperation foruseintheshutdowncoolingmode.Inthisevent,cooldownwasstartedapproximately halfanhourafterthereactorshutdown.

Cooldownusingnaturalcirculation proceeded smoothlyforaboutanhouranda,halfatwhichtimecomponent coolingwaterwasrestoredtotheReactorCoolantPumps.Thedecisionwasmadenot'torestarttheRCPs.Itwasreported-'-,':.-';.';.

thatthreefactorsledtothisdetermination:

..)TherewasconcernthattheRCPrestartcouldcauseasealfailure2.)Aprevioussuccessful naturalcirculation cooldownhadbeen,;.'.accomplished in1977.3.)AtthetimethecoolingwatertotheRCPswasrestored, (approximately l-l/2hoursaftereventinitiation),

cooldownusing,.'atural circulation wasprogressing smoothly.

Thecooldownlimitsprescribed bytheprocedure werenotexceeded.inthisevent.However,useoftheprocedure producedvoidinginthereactorvesselheadareaindicating thattheprocedure neededtobechanged.ComonentCoolinMaterThecomponent coolingwatersystemprovidescoolingtonumerouscomponents bothessential andnon-essential.

Thefourreactorcoolantpumplubeoilandsealcoolersareconsidered non-essential loadssuppliedthroughacommonheaderandreturnline(seeFigureOPS-1).Thesupplyheaderandreturnlinespenetrate containment.

Therefore, thesupplyvalves(HCV-14-1, f4-7)andreturnlinevalves(HCV-14-2, 14-6)areessential tocontainment isolation.

AtSt.Lucie1anelectrical shortfrommoistureremovedpowerfromthesolenoidonthereturnlineisolation valve(HCV-14-6) causingittoclose.Thisstoppedcomponent coolantwaterflowthroughthereactorcoolantpumpsealcoolers.AtSt,Lucie1,alossofcomponent coolantwatertothereactorcoolantpumpnecessitates stoppingtheaffectedreactorcoolantpumpwithin10minutestominimizeriskofsealdamage.FPBLhasprovidedatemporary fixtoallowthefourisolation valvestobere>>openedquicklyintheeventofanelectrical orpneumatic failure.Thisincludesanitrogenheadertoreplacetheairandquickconnectfittingstoallowbypassing

-'.;-'-*',--",.'.':.'.:'"'""""

'-'",.'-:.:

'OPS-3'-."'-.",-,i

.;;..j.-'~'-,'APPENDIX OPS thepilotvalve.Longtermmodifications arebeingconsidered thatwillprovideanadditional coolingwaterheaderfromthecontainment coolerssupplyasabackuptothenormalsupplyofcomponent coolingwatertothereactorcoolantpumps.OPS-4APPENDIXOPS 1I AirsupplyAirsupplyAirsupplyAirsupplySealcoolerSealcoolerSealcoolerSealcooler1B21B1AirsupplyReactorBuildinghrI;r"I.C~~CCWsupplyIIIIIIIII~AirsupplyCCWreturn)HCV14%IHCV14-2L~~~JHCV14-7HCV14-1FigureOPS-l.

f4I~'

APPENDIXNCCOPERATIONS DURINGNATURALCIRCULATION/COOLDOWN

ylAPPENOIXNCCOPERATIONS DURINGNATURALCIRCULATION/COOLDOWN Thisappendixidentifies conditions thatmayexistduringnaturalcirculation

-whicharedifferent fromthoseexistingduringforcedcirculation byReactorCoolantPumps(RCPs).Theseconditions areconsidered intwoplantevolutions:

1.Hotstandbyusingnaturalcirculation E/2.Plantcooldownusingnaturalcirculation Thisappendixcouldbeusedinthereviewofcurrentprocedures orthedevelopment ofnewprocedures.

HotStandbUsinNaturalCirculation Thenaturalcirculation capability oftheplantprovidesameansofdecayheatremovalwhentheRCPsareunavailable.

Naturalcirculation flowratesaregoverned.

bytheamount.ofdecayheat,component elevations; primarytosecondary heattransfer, loopflowresistance andvoiding.Theconditions discussed inthissectionrelatetomaintaining adequateprimarytosecondary heattransferandthepotential effectsontheprimarysystemofvolumesofhotfluidwhichdonottakepartinnaturalcirculation.

Whileinnaturalcirculation, adequateheattransferandcoolantflowaredepen-dentonadequateinventory inboththeprimaryandsecondary systems.Thenumberofsteamgenerators requiredtosupportprimarytosecondary heattransferandcoolantflowislessthanthenumberofsteamgenerators providedwitheachplant.However,whenconditions callfortheuseofnaturalcirculation

'forextendedperiods,heatremovalshouldbeaccomplished throughtheuseofallEavailable steamgenerators.

Theuseofallsteamgenerators undernaturalcircu-lationconditions willprovideamoreevenheatremovalintheoverallplantandeliminate additional pocketswherehighertemperature fluidscanexist.Volumesoffluidwhichdonottakepartinnaturalcirculation maybesubjecttovoidingduringdepressurization.

Furthermore, non-flowing volumesdonotmixwhenboratingforshutdown, andthelaterdilutionmustbeconsidered.

NCC-1

eThesteamgenerator waterlevelrequiredtosupportheattransfervarieswitheach'-typeofsteamgenerator installed.

Maintaining waterlevelabovethetubesonthesecondary sideofthe"U"tubesteamgenerator andhighonthetubesoftheoncethroughsteamgenerator canaidincondensing voidsandcontinuing naturalcircu-lationintheprimarysystemshoulddepressurization orlossofinventory take'lace.Therefore, maintaining thewaterlevelabovethetubesor'ighonthetubesshouldbeconsidered.

Overcooling transients aremoreafunctionoffeedratethantheyareofsteamgenerator waterlevel.Theratethatsteamgenerator

.secondary waterlevelisincreased shouldbelimitedtopreventexceeding the,.',"",,'-.'-;-'-"='maximum cooldownrateallowedfortheplant.Whilemakinglevelchangesinlowmounted,oncethroughsteamgenerator s,theresulting RCStemperature changemaymomentarily interrupt thenaturalcirculation flowrate.

Ifthewaterinventory isadequateontheprimaryandsecondary sidesofthesteamgenerators, naturalcirculation willresume.~'Voidingintheprimarysystemisdependent onthetemperature andpressureofthe.coolantandtheamountofcoolantinventory inthesystem.Regionswherenaturalcirculation isnotoccurring (idlesteamgenerators, orreactorvesseljiead)canbecomehotspots,thatreachsaturation conditions whensystempressureisreducedduringcooldown.

Mostplantsdo,notmeasuretemperature intheregionsmostlikelytoreachsaturation.

Increasing pressure; additions ofchargingwater,'nd maintaining levelsinthesteamgenerators aspreviously described combinetoreduceoreliminate voidswhichmaybeformedinadvertently.

Lossofsubcooling andincreaseinLTwouldwarnofanimpending lossofflow.Thotwouldprovidethefirstindication ofalossofsubcooling resulting fromtherapidexpansion ofhotwaterintotheflowingloopsfromthereactorvesselheadregion.Coreexitthermocouples wouldnotseethischange.Confirmation offlowwhileinnaturalcirculation isaccomplished throughtheuseoftemperature indications.

Thoseindications areTcold(Tc)andLoop~T(Th-Tc).Tcshouldattainavaluewhichisafewdegreeshigherthanthesaturation temperature ofthesecondary inventory.

TheloophTshouldattainavaluewhichislessthanthefullpower.AT.ExamplesofthevaluesforATatSt.LucieareshowninFiguresT/H-Iand2.ThevalueforaTmaydecreaseslightlywithtimeduringasubsequent cooldownasthevaluesofdecayheatandsystemtemperatures fall(FigureT/H-Iand2).WhenTcandLoophTattainthevaluesdescribed above,flowandheattransferhavebeenachieved.

ThandTcaretwoparameters whichneedtobeindicated overthefullrangewhileinnaturalcirculation orcooldownusingnaturalcirculation becauseoftheinputstheyprovidetoLoopATandthesubcooling monitor.'Further, Thprovidesthefirstindication ofalossofsubcooling andpotential voidingintheflowstreamatthehighestelevation intheloops.CoolDownUsinNaturalCirculation Inadditiontotheconsiderations discussed undernaturalcirculation, thefollowing itemsimpactplantstatusduringcooldownmorethanathotstandbyconditions:

1.Boration2.Cooldownrate3.Reactorcoolantinventory control4.Ventingthereactorvesselhead5.Safetysystemoperations 6.Condensate

-inventory requirements.

BorationLowcoolantflowratesandstagnantregionsofcoolantimpairtheabilitytoachieveequilibrium boronconditions throughout theReactorCoolantSystem(RCS}.Thereducedflowrates experienced duringnaturalcirculation increasethetimeittakestoachieveboronequilibrium throughout thesystem.Reactivity changeswhichoccuruponshutdownandcooldown, par-ticularily xenonandtemperature, shouldbeanticipated inadvancethroughearlyboration.

Anynon-flowing regions,suchasthecoolantinthereactorvesselabovethenozzles,shouldbeconsidered intermsofthedilutionwhichwilloccurwhentheseregionseventually mixwiththepreviously boratedflowingregions.Idlesteamgenerators aswellasthereactorvesselheadcancontainvolumesofwaterwithboronconcentrations thatwereusedduringat-powerconditions.

Theconditions discussed aboveshouldbeconsidered inthecoolantsamplingpractices usedduringnaturalcirculation.

Untilfinalmixingofallregionshastakenplace,samplingfromallflowingregionsoftheNCC-3

'kI~I reactorcoolantsystemshouldgiveahigherthanexpectedboroncontent.Samplesourcelocations andfrequency shouldbeincreased overthoseusedduringforcedcoolantcirculation.

CooldownrateUnderforcedcirculation, cooldownofthereactorcoolantsystemisrelatively eventhroughout.

Thecooldownrateislimitedbyconsideration ofthetransient temperature differential acrossthewallofthereactorvessel.Cooldownundernaturalcirculation causesanadditional transient temperature differential intheverticaldirection inthereactorvesselwallbetweenthetopofthevesselflangeandthecoolantnozzles.Con-sideration oftheincreased thermalstressesproducedbythenaturalcirculation cooldownmayresultinsettingaslowerrateofcooldownthanallowedunderforcedcirculation.

Inaddition, amaximumtemperature differential betweenthetopofthevesselandthecoldlegmaybeimposed.PriortoformingasteambubbleunderthereactorvesselheadatSt.Lucie,thecooldownoftheheadregionwasmuchslowerthantherestofthereactorcoolantsystem.Hostlikelyatleastsomeamountofcoolantatthetemperature Thot,585'F,remainedunderthereactorvesselheadafterthetrip,asthecontinued operation ofthereactorcoolantpumpsaftertriplastedbutafewminutes.At6:15amitappearedthatthesteambubbleundertheheadfirststartedtoform.Thepressureatthattimewas900psia,corresponding toasaturation temperature of532'F.Bythismethodthecooldownrateoftheupperheadregionoverthefirst3.7hoursaftertripisestimated tohavebeen14'F/hr.Otherassumptions ontheinitialtemperature oftheheadregionandthetimeofinitialbubbleformation maybemade,whichyieldestimates oftheheadregioncooldownraterangingfrom10to20F/hr.AtSt.Lucie,thesystempressureshouldbereducedtoabout200psigbeforebringingtheshutdowncoolingloopintooperation.

Consequently theheadregionwouldneedtobelowerthan387'Ftopreventformingasteambubble.Ifinfacta14'F/hr.cooldownoftheheadregionwouldoccurwithouttheformation ofasteambubble,thenabout14hoursofcooldownusingsteamgenerators wouldberequiredpriortoinitiating shutdowncooling.Shouldthesystemcooldownrateand/orthetemperature differential allowedbetweenthevesselflangeandnozzlesbereducedfrom

,Co theSt.Lucieevent,thencooldownoftheheadregionwouldrequiremoretimethantheexampleabove.Reactorcoolantinventory controlShouldasteambubbleforminthereactorcoolantsystemwhilereducingpressure, ariseinpressurizer levelwouldresult.Ifchargingand/orletdownweretoremainunderautomatic control,coolantinventory wouldbereduced'asthecontrolsystemattempted tocorrecttherisinglevel.Con-sequently, manualcontrolofchargingandletdownshouldbeused.Generally, chargingshouldexceedletdownbyanamountequaltothecoolantshrinkage rate.Theplantoperators shouldkeeptrackofinven-toryneeds,additions, andsubtractions throughout thecooldown.

Pressurizer levelanomalies resulting fromsteamformation hindertheoperators'bility todetectleakageoralossofcoolantfromthesystem.Oncesystemdepressurization hasbegun,andtheautomatic initiation ofsafetyinjection hasbeenblocked,pressurizer levelandlossofsubcooling aretheprimaryparameters 1'eft-:to theoperators todetectalossofcoolant.Sincelevelanomalies can.occurduringthecooldownundernaturalcirculation, itisimportant thatsubcooling rela-tivetoThotandcoreexitthermocouples bemonitored.

Shouldasteambubbleformundertheheadwhilesprayingthepressurizer, sprayshouldbediscontinued, directing chargingtotheloops.Chargingtotheloopsshouldbecontinued atleastuntilthefallingpressurizer waterlevelstopsorreverses.

Onlyatthatpointcantheoperators usepressurizer waterlevelasanindicator ofsysteminventory.

Fallingpressurizer waterlevelshouldnotbereversedbysprayingthepressurizer.

Inordertominimizetherateofdepressurization, andtherebyminimizethesizeofpotential coolantlosswhichcouldbemaskedbyanomalous pressurizer waterlevelchange,theauxiliary sprayrateusedshouldgenerally benomorethanthedesignminimumchargingflowforthesystem.Inaddition, auxiliary sprayshouldusuallybeheatedbyletdownflowinordertomeetthemaximumtemperature differential allowedbetwenthepressurizer andthesprayflow(atleastinsystemswhichincludearegenerative heatexchanger).

Shouldinventory controldictatestoppingtheletdownflowtoconservereactorcoolantsysteminventory, thenpressurizer sprayshouldbetemporarily discontinued aswelltostopthe depressurization andallowthepressurizer waterleveltogiveamorereliableindication ofsysteminventory.

VentingthereactorvesselheadPlantswhichhaveaventinstalled fromthereactorvesselheadtothepressurizer shouldopentheventwhilereducingsystempressure.

Thehigherwaterlevelofthepressurizer willpushsteamgenerated under.thereactorvesselheadintothepressurizer, whereitmaybecondensed byI.auxiliary spray.Coolingofthereactorvesselheadregionwillresult-;..;.from thegeneration anddrawingoffofsteam.Bycoordinating thesystemdepressurization withthesystemcooldown, thevesselheadregionmaybecooledsimultaneously, speedinguptheoverallcooldownevolution.

Safetysystemoperations Incooldowns usingforcedcirculation,.safety systemsaretakenoutofoperation basedoncoolanttemperature andpressure.

Innaturalcirculation cooldowntheoperatormaynotknowthetemperature ofthehottestpointinthesystem(underthereactorvesselhead).Considera-tionshouldbegiventotakingsafetysystemsoutofoperation atlower-indicated temperatures thanthoseusedduringnormalforcedcirculation cooldown.

Condensate inventory requirements Theamountofcondensate inventory requiredtosupportacooldownusingnaturalcirculation canincreasesignificantly overtheamountrequiredtosupportanormalcooldown.

Theeventwhich'edtothenaturalcirculation condition mayalsorenderthenormalheatsinkandtheinventory replace-mentsystemunavailable (e.g.,lossofoff-sitepower).Therefore, theuseoftheatmospheric steamdumpsystemmaybecometheonlymethodofheatremovalandwilldepleteavailable inventory.

Condensate avail-.abilitymaylimittheamountoftimethataplantcanmaintainhotshutdownconditions beforestartinganaturalcirculation cooldown.

Thetimethattheplantremainsatahotshutdowncondition beforestartingthecooldownusingnaturalcirculation andthelongercooldowntimesuggestthatareviewbemadetoensurethatexistingcondensate storagecapacityissufficient fornaturalcirculation cooldown.

Aslongastwentyhoursofcooldownwhiledumpingsteammayberequiredto.coolfromhotstandbytohotshutdown~heretheshutdowncoolingsystemmaybeused.NCC-6f

REFERENCE LIST~~.4'4~4~'4I*

REFERENCE LISTI.OPERATING LOGSReference 0Title1~4~5.9.10.29.30.49.50.72.AppendixAtoOperating Procedure No.0030127Rev.19-Pressurizer Temperatures andPressures 3:30am-3:00pm.Chemistry LogsfortheRCSandRWT6/1/80-6/30/80.Pressurizer/Heatup/Cooldown Curve-6/11/80PlottedcooldowncurveforRCSandpressurizer.

ShutdownCoolingLogSheet-6/ll/8012:00pm-11:00pm.LogSheetforPowerOperation 6/11/80VCT,Charging, letdown-12:00am-ll:00am.NCCOLogSheet0'2forPowerOperation

'6/11/80Pressurizer

pressure, SteamGenerator LevelsandPressures

-12:00am-ll:00am.N.O.(NuclearOperator)

LogSheetg4(3pages)Miscei.laneous temperatures andpressures forvari<uscoolersandpumps-12:00am-10:00pm.H.O.(NuclearOperator)

LogSheetfl-4&6(5pages)Plantsupportsystemsincluding CCW12:00am-10:00pm.N.O.(NuclearOperator)

LogSheet81-$86(5pages)PlantSupportSystemsincluding CCWandRWTlevelsfor6/12/80-12:00am-10:00pm.ControlRoomOperator's Log-6/ll/80(2pages).WatchEngineer's Log-6/11/80(2pages).H.O.LogSheet-6/11/80-6/13/80 (2pages).II.COMPUTERPRINT-OUTS 6.SequenceofEvents10:49pm-6/10/80through16:37pm-6/11/80.16.DigitalDataProcessing System(DDPS)02:00-16:00,6/ll/80-Calorimetric points,Incoredetectors, IncoreThermocouples andmajorequipment startsandstops.III.PLANTPROCEDURES 22.Emergency Operating Procedure 0120040Rev.4LossofReactorCoolantPumpFlow/Natural Circulation.

REF-1 23.24.71.73.74.75.Emergency Operating Procedure

-120040Rev.5LossofReactorCoolantPumpFlow/Natural Circulation.

Off-Normal Operating Procedure 0120034Rev.7ReactorCoolantPump-Off-Normal Operation.

Operating Procedure

-0120021Rev.5ReactorCoolantSystemDraining.

Operating Procedure

-0030127Rev.19ReactorPlantCooldown-HotStandbytoColdShutdown.

Off-Normal Operating Procedure 0120034Rev.6ReactorCoolantPump-Off-Normal Operation.

Off-Normal Operating Procedure 0310030Rev.10Component CoolingWater-OffNormalOperation

'IV.SYSTEMDESCRIPTIONS ANDPAIDSystemDescriptions:

34.35.36.37.SystemPAID39.40.41.42.43.44'5.46.ReactorInternalStructures 83(CalvertCliffs).ReactorCoolantSystemg5(CalvertCliffs).gChemicalVolumeandControlSystemg6(CalvertCliffs).SafetyInjection Systemf7(CalvertCliffs).ISt.Lucie:ChemicalandVolumeControlSystemFigure9.3-3.ChemicalandVolumeControlSystemFigure9.3-5.ChemicalandVolumeControlSystemFigure9.3-4.ReactorCoolantPump-Figure5.5-7.SafetyInjection SystemFigure6.3-1.SafetyInjection SystemFigure6.3-2.Component Cool'ingWaterFigure9.2-2.ReactorCoolantSystemFigure5.1-3.REF-2 I

47.65.Containment SprayandRefueling WaterSystemFigure6.2-28.ShutdownCoolingFlowOperational ModeDiagramFigure9.3-6.V.SYSTEMSTRIPCHARTRECORDINGS 19.20.26.ReactorMakeupWater(RMW)FlowShutdownCoolingHeatExchanger InletTemperature SILowPressureHeaderTemperature.

Refueling WaterTank(RWT)Level28.Activity1.2.)3.LevelsPlantventparticulate PlantventgaseousPlantventiodineContainment gaseous.31.32.48.51.52.53.54."8"Auxiliary Feedwater Flow"A"Auxiliary Feedwater FlowSteamGenerator IAand18Pressure/Turbine InletPressure.

BoricAcidFlowBoronConcentration WideRangeLogNuclearInstrumentation LPSIFlow55.56.57.58.59.60.61.62.63.64.66.Loop"A"and"B"HotLegTemperature.

TaveandTrefTemperatures (RRS82)Loop"A"and"B"ColdLegTemperature TaveandTrefTemperatures (RRS81)LPSIPumpDischarge PressureProcessRadiation Monitor(GrossCoolantActivity)

FlowratefromReactorCavity.Pressurizer PressurePressurizer LevelSteamGenerator 1Aand18LevelFeedwater andSteamFlowforSteamGenerator 1AREF-3 k

67.Pressurizer Level(1977Transient)

VI.MISCELLANEOUS REFERENCE MATERIAL17.18.38.68.69.70.DDPSCalorimetric LogInstrument PointDefinition Sheet.DDPSCalorimetric LogInstrument Identification Log.Containment Penetration PipeI.D.Plan.Recordedpressurizer leveltemperature compensation curves.St.Lucie-PlantTransient Report.Photograph

-RepairedFlange.jf4REF-4

('i GLOSSARYOFTERMS,ABBREVIATIOHS ANDACRONYMS GLOSSARYOFTERMSCEACCWFP&L9pmHCVIf.",LPSIMicrocuries/ML MSIVPSIRCPRCSControlElementAssemblies Component CoolingHaterFloridaPowerandLightGallonsperminuteControlValveLowPressureSafetyInjection Microcuries permi'lliliter MainSteamIsolation ValvePounds'persquareinchReactorCoolantPumpReactorCoolantSystemWtTH-Tc0THorTHOTTC'"TCOLOHotLegTemperature ColdLegTemprature

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