ML081770470

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McGuire May Examination 05000369 and 05000370/ 2008-301 Facilities Post-Examination Comments (Part 1 of 2)
ML081770470
Person / Time
Site: McGuire, Mcguire  Duke Energy icon.png
Issue date: 06/25/2008
From:
NRC/RGN-II
To:
Duke Energy Carolinas
References
50-369/08-301, 50-370/08-301
Download: ML081770470 (32)
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Attachment 1a Common Question 53PageI of 8 After further investigation we propose that Question53be deletedduetono correct an swer.Theoriginal a s sumption w asduetothelo wering VI (InstrumentAir) pressure the S/G feedreg valveswouldfa il clo sed re sulting in increasingfeed pump di scharg e pressure to th e point wherethefeedpumpswou ldtriponhighdi scharge pressure.Whil ethefailur e mechani smfortheFRV's i s correctonalos s of air (closed), th e re sultin g Rea ctor trip occursduetolow S/G levelnotfeedpumpdi scharge pressure.Thiswas validatedonou r simulatorwithaloss ofVIrampedi noveraperiod of5to10 minutes which resulted in the reactor tripping on low S/GlevelwhenVIpress had degraded to appro x.40psig.WhileFWPdi scharge pressuredidincrease, the action oftheFWP control system to maintain th e program D IP at setpointre sulted in a decrea seinFWP speedasthe FRV's clo sed.This a ction delays the increase inFWPdi s charge pressure.tothe point where lowering S/G level willreach trip setpoint prior to increasing F WP dischargepress.In 4 different VIfailurescenarios withvarying leak sizes andramprates, the reactortr ipped du e to S/G levelpriorto FWPdischarge press reaching trip setpoint.Thefeedpumpspeedc ontrolsystemi s designed to maintain a D IP set point betweenMainSteam header pressure and Feedwater Header p ressure.This setpoint is ramped from40p sidat0%powe rto1 75 p sidat100%power.(seep age 5 ofthisatt a chment)Whena V I systemleaki s in serted , th e re sulting low ering VI header pres s c auses the FRV's to slowlyclose.As the y clo se ,FWPdischarge press increases.Thiscauses the S M/C F D IPtorapidly increaseandwas observed tobeashigha s400psid.TheFWP control systemre spond s to slowth eFWPspeedin a n attempt to maintain th e pro grammed D IP.In ev ery casee xcept a catastrophi c failur e wher e the V I header rapidly d epressurizesthisaction significantl ydelaysthe increaseinFWP dischar ge pressure.A catastrophic failure ofVIi snotconsistentwiththe conditionsestablishedinthestem of thi s question.Onefinaldat a point addedtotheend of thi s attachm ent is copyo fPIPM 87-0020 8 whi ch documentsa n actualloss of VIin1987wherethe reactor trippeddueto S/GLoLole vel afterappro x.5min.Thisisconsistent withwhat we ob served during our simulator validations.

Question53asks,"WOOTFwillb e th e FIRSTtotripthere actor".LoLo S/Gleveli snotlistedin any of the proposed answers.Basedonthe informa tion aboveandthe attacheddo c umentation

, w efeelthi s q uestion should be delete dduetohavin g no correct answer.

Tier#Group#K/A#ImportanceRating 1 1 065 AA2.08 2.9 (Abilitytodetermineandint erpret thefollowingastheyappl ytotheLossof InstrumentAir:Failure mode sofair-operated equipment)ProposedQuestion:Common53BothUnitsareat100%powerwhen

  • MNS experiencesalossofVI.*VIHeaderpressureonbothunitsis30psigand continuestodecrease.WhichONE(1)ofthefollowingwillbeFIRSTtotripthe reactoranditsbasis?

A.OTDeltaTtripduetotheMSIVsfailingclosed.B.High-HighSGleveltripbecausethe FeedwaterRegVa lvesfailopen.C.TurbineTripduetoFeedPumpTripbecausethe FeedwaterRegValvesfailclosed.D.High pzrLeveltripduetotheChargingFlowControlValvefailingopenwithLetdownisolated.

Proposed Answer: C Explanation (Optional)

A.Incorrect.IfMSIVsfailcloseditcouldcauseatriponLO-LOSGleveloronOTDTduetoTaverising.FRVsfailingwillcausethetrip significantly fasterthanMSIVfailure.Plausiblebecauseuntilarecentmod

,theMSIVs d idfailcloseonalossofVI.B.Incorrect.

Feedwaterregvalvesfailclosed,but plausible becausethisisthereactortrip mechanismiftheydidfailopen.

C.Correct.Reactortripwilloccurduetoturbinetrip.If fedwaterregvalvesfailclosed

,FeedPumpswilltriponhigh dischargepressure,whichdirectlycausesaturbinetrip

.D.Incorrect.Thiswouldcauseareactortrip,butata significantlylatertime than feedwaterregvalvefailure.Chargingflowcontrolvalvefailsopenandletdownisolatesonlossofair

,soPZRlevelwillberising TechnicalAP-22Background Reference(s)Document(p22Rev12)

AP/1/A/5500/22 Enclosure12p104106 ,Rev27 CF-CFp19Rev32 Proposed referencestobeprovidedto applicants during examination:

Learning Objective:QuestionSource

CF-CFObj4 Bank#ModifiedBank
  1. New (Note changesorattach____parent)x Question History:LastNRCExam

Question Cognitive Level:10CFRPart55 Content: Memory or Fundamental Knowledge Comprehension or Analysis55.415 55.43 x Comments:KAismatched because item evaluatesthefailuremodeofair operated equipmentthatwillcausea reactor tripRFAConcurs 4/24/08 DUKE POWER

1.0 INTRODUCTION

1.1 Purpose Objective#1 MCGUIRE OPERATlONSTRAININGReferenceFig

.7.1.The purpose of the Feedwater Pump Speed Control Systemisto provide a variable speed demand signaltothema in feedwater pump turbineswhichis programmed to maintain the Feedwater Regulating(FlowControl)Valvesin their opt imum throttling position.Thesystemalsooperatesthe FeedwaterPumpsinconjunctionwiththe FeedwaterControlValvestomaintainsteam generatorwaterlevelwithmaximumefficiency

.1.2 General DescriptionTheSteam GeneratorLevelControlSystemcomputesadesiredlevelthat isbasedonreactorpower

.Tomaintainthisdesiredlevel

,acontrolsignalis developed.Thesignalfunctionstopositionthe FeedwaterRegulatingValves

,andthuscontrolfeedflow

, foreachofthesteam generators

.TheMainFeedPumpSpeedControlSystemisdesignedto complementtheoperationoftheWaterLevelControlsystem

.Itcomputesadesiredpumpspeedthatisbasedon auctioneeredHINCdeltaT (reactor power).Thissignalfunctionstoregulatethesteamflowtothemainfeedpumptu rbines,controllingtheirspeed.Variationofpumpspeedinthisfashionresults in:*Reducederosionof feedwater regulat ingvalveflowcontrolsurfaces

.*Improvedfeedregulat ingvalveflowcontrol(throttling) characteristics

.Variab lespeedmainfeedpumpsarefavoredbecausetheyaremore economical inlargeplants

.ThereislesslostenergywhenthespeedismatchedwiththedesiredDifferentialPressure(DeltaPorDP)

.Steamheaderpressure iscomparedtofeedpump dischargepressuregeneratinganActualDPsignal.TheDPsignaliscomparedtoaprogrammed setpoint determined from auctioneeredHINCdeltaT(reactorpower)and generatesthespeeddemand signal.Correctionsmaybeaddedforflowimbalancebetweenthepumps

.2.0 COMPONENT DESCRIPTION 2.1 General Operation I Objective#6 IThesystemutilizesthreebasiccontrolloopstocontrolthefeedpump.The feedwater loop , the governorloop,andactuator loop.Theseloopsandtheir relationship areshownondrawing4

.1.Eachoftheseloopsisaproportionalplusintegralcontrolloop (P+I).Basicallythesearecascadingcontrolloopsinthatthe feedwatercontrolloopoutputistheinputtothe governorloopandtheoutputofthe governorloopistheinputtotheactuato rloop.Thisassumesthatthecontro lsareinauto.Theinputforthe feedwaterloopisthe feedwaterdemandsignalwhichisthe programmeddeltaPforthepowerlevelofthereactorassensedby auctioneeredhiNCloopdeltaT

.OP-MC-CF-IWEFORTRAINING PURPOSES ONL YPage9of57 REV.17 DUKE POWER MCGUIREOPERATlONSTRAINING 7.3 Feedpump ap Program w/AMSAC Avoidance (03/17/06) 205 2 00 1 95 190 18 5 1 80 175 17 0 165.1 60.155.15 0......14 5'8 1 4013 5 UJ en 130 Q.o 125 120 115 1 10.1 05 1 00 9 5 90.85 80.75 7 0 65.o 5 1 0 1 5 20 25 30 3 5 404 5 50 55 6 0 65707 5 80 85 90 95 100105 11 0 11 5 120 125%POWER OP-MC-CF-IWEFORTRAINING PURPOSES ONL Y Page49 of57 REV.17 AP/1 and 2/Al5500/022 (Loss of VI)STEP 13: PURPOSE:PrompttheoperatorstowatchS/GlevelsbecausetheCFcontrolvalvesfailclosedonalossofVI.IfS/Glevelscan

'tbecontrolled,theOperatorisdirectedtotripthereactor.

DISCUSSION:TheCFcontrolvalvesuse0-60#valveoperatingair.Dependingonthenatureoftheproblem w ithVIandconsideringlinelosses,etc

.,thesevalvescouldstartfailingat70#ormoreVIpressureasindicatedinthecontrolroom.Theoperating philosophyregardinglossofMain Feedwateratpoweristotripthereactor

.ThiswillpreventchallengingtheLa-LaS/G automaticreactortr ipandwillresultinbetterinitialconditionsatthetimeofthemanualtrip.RefertoPIP2-M-87-0208wherea automaticreactortripoccurred5minafterlossofoffsitepowerdueto lossofVItotheCFvalves.IftheCFvalvesweretogettolessthan25%open(for30secormore)on3outof4S/Gs,anAMSACcouldalsobegenerated

.Formostscenarios

,it'slikelytheoperatorwillhavemanuallytrippedthereactorpriortothisoccurring.

REFERENCES

PIP 2-M-87-0208Page15of46Rev12 MNSLOSSOFVIPAGENO.AP/1/N5500/228of120UNIT1Rev.27 A CTI ON/EX PECTEDRESPONSE 11.(Conti nued)m.ControlNC temperatureasfollows:*ThrottleNOflow.

RESP ON S E N OT OBTAI N E D NOTE*KCtoNOHxflowshouldbeclosetoflowp riortolossof VI,sinceitisnormallycontrolledbymotoroperatedvalves.*KCtoNOHXflow indicationsfailslowdur ingalossofVI.Alternate indicationsareavailableatthefollowing locations ,ifneeded:*1A:1KCFT-5670(auxbldg,733+2',wes tofcolumnMM-54)*1B:1KCFT-5680(auxbldg

,733+4',westsideofcolumnJJ

-55).*IFNC temperature isgreaterthan 200°F ,THENmaintainKCflowtoNOHx greaterthan2000GPM

.*ThrottleKCFlowtoNOHxas required.12.IFATANYTIMEVI pressure is less than70PSIG,THEN align B Train RN toSNSWPPER Enclosure 7 (Aligning B Train RN to Pond).CFControl ValveswillfailclosedonlowVIpressure

,whichmayresultinAMSACactuationandLoLo S/G level.13.Check S/G levels-AT PROGRAMMED LEVEL.IF S/G levels are going downinan uncontrolled manner, THEN perform the following:a.Tripreactor.

b.Continuewiththisprocedureastime allows.c.GOTO EP/1/N5000/E-0(ReactorT riporSafetyInjection)

.

DUKE POWER Objective#4',C._.P6 6 b F'B"".MCGUIRE OPERA TJONS TRAINING The conditions which will result in both main feed pumps tripping:*if all three CBPs trip*ona Safety Injection actuation*on SIG Hi-Hi-Ievel (P-14)(83%)*onHiHiDog House level in either inner or outer Dog House (12 inches)The conditions which will result in tripping the associated main feed pump:*two out of three of its suction pressure switches are low (230 psig)*two out of three of its discharge pressure switches are high (1435 psig)*manual trip*two out of three low bearing oil pressure (7 psig)*two out of three low vacuum (14 inches Hg)*overspeed*fire lockout*thrust bearing wear (0.01 inch axial movement)The status of the suction and discharge pressure switches can be determined from the"Condensate 2 of 3 Logic Panel" located in the Turbine Building basement near the BB demineralizer room across for Column1F24(refertoDrawing7.3).When A(B)CF pump is tripped, solenoid valve 1CFSV0010 (1CFSV0040) is energized which closes A(B)CF Pump piston operated discharge check valveCF1(CF4).This will prevent flow reversals through the idle pump and prevent damage to the pump and piping due to waterhammer.TheCF pump suction (CM266 and CM272)and discharge (CF2 and CF4)valves are motor operated valves whichcanbe controlled using OPEN/CLOSE push buttons fromMC-10(refertoDrawing7.4).The A(B)CF pump turbine high and low pressure stop valves can not be raised (opened)until its suction valveCM266(CM272) and its discharge valveCF2(CF5)are open, as well as the CM Booster Pump recirc valve CM250andCF System Flush ValveCF124are closed.In additionCF124can not be opened unlessACFP suction valve(CM266)and discharge valve(CF2)are openORBCFP suction valve(CM272)and discharge valve(CF5)are open , and both CF pump turbines are tripped.OP-MC-CF-CF FOR TRAINING PURPOSESONLYPage19of107 REV.32 Problem Investigation Process McGuire Nuclear Station la Action Cate 0 Problem Identification Discovered TimelDate:

10:21 09116/19 87 Occurred TimelDate:

Unit(s)Affected: Unit 2 Mode I%Powe r UnitStatus R emarks Sy stem(s)Affected: CF EPB ND VI F e edwater Sy stem 6.9KVNormAu x&RCP Swgr P ower Sys ResidualHeatRemovalSystem Instrument A ir System Affected Equipment."::::: Equipment T i;g::.EcOde::::: M;!.nuf: eturer:'r_.I 0"_Location of Problem: Bld g: Column Line: EIev: Location Remarks: Method U sed to Discover Problem: Brief Problem

Description:

APPROX.5 MIN UTESAFTERLOSSOF OFFSITE POWERTOUNITI , UNIT 2 E Detail Problem

Description:

APPROX.5 MINUTESAFTERLOSSOF OFFSITE POWERTOUNITI ,UNIT2 EXPERIENCEDAREACTORTRIPDUETO S/G-LO LO LE VEL.FEEDWATER REGULATOR VALVES FAILED CLOS EDDUETOLOSSOFSTATIONAIR (VI)Other Units/Components/Sy stemslArea s Affected(Y,N,U):

U Industrv Plants Affected(Y,N,U):

Immediate Corrective Actions: Immediate Corrective Action Documents 1 Work Orders: Problem Id entified B y: P roblem Entered B y: M-RGC M-SRG Date 0 911611987 0 911 6119 87 Screening Act ion Category:RootCause performed?051281200810

39Page1PIPNo: M-87-00208 Problem Investigation Process McGuire Nucl ear Station Significance C odes: OEPN o:OtherReportNos: M8 7-075-0 Event Codes: 88Convertoldpipdatat oNewPIPrelationaldatabase Screening Remarks: Assignments:

Responsible Groups(s)forP roblem Evaluation: Respon sibleGroupf or Present Operability: Responsible Gro upforR eport Supp ort Info: Responsible Group forReportability: Responsible G roupforOver allPIPApp roval: M-SRG M-RGC N/A M-RGC M-SRG Safet y Review Regul atory Compliance Regu latory Compliance Indiv onfile Te am RJD4373 O rou M-SRG Dat e 0911611987 Present Operability Responsible G roup: M-RGC St atus: Closed Sys/Comp Operable?(Y,N,C,E,T): Y Requ ired Mod e: Comment s: R ep ortab ility Responsible Group: lndiv M-RGC Team St atus: Closed Grou M-RGC Date Problem Reportable(Y,N,E)

Y Reportable Per: Comments: LER , N/A SiRnature T voe Indiv Team Group Date Assigned To: M-RGCDueDate: Evalu ation Assigned To: M-RGC 09116119 87 Investigation Report: OS/28/200810:39 Page 2PIPNo:M-87

-00208 Problem Investigation Process McGuire NuclearStation Respon s ible Group: ActDate: Inve stigator: Group: Due Date: 10/22/1987 Date DuetoV PorS ta.Mgr: Dat e Regulatoryo r AgencyRptD ue: Dat e Investigation ReportApproved: 10/29/I9 87 NR C Cause Code s: A3c3 A n ActionW as Perf orm ed With Insufficient Precision Report Support Info: Respon sible Group: I Signature TyPC Indiv St atus: Closed Team Group Date: Problem Evaluation I Event 1 88 188 Cause Cod e A3c3 N/ACaue Descripti on Old CauseCodea t McGuireNotApplicabl e Primary Ye s NoCauin g Group s V-UNK M-IAE Probl em Evalu ation From: Resp.Group: M-SRG OEDUComments: Stat us: Clos e d OEDBChecked: No Rem arks Comment s: Du e t otheelectronicuploadingofinformation, anymissingPIRinformationislocatedintheMaster Filea rea. Type Indiv Team Group Date Assigned To: M-SRG 09/19/1987 Due D ate: 10/16/1987 Corrective Actions No CorrectiveActionsforthi s PIP Final and Overall PIP Approval Resp onsibleGroup:M-SRG Status: C lose d Signatur e T ype Indi v Team Groun Dat e Assigned To: onfile M-SRG Appro ved B y: onfile M-SRG01/31/1990-AnySupplemental Concurrence Sign atures AboveDoNot Affect PIP Closure.OS/28/2008 10:39 Page 3 PIPN o: M-87-00208

      • <I Problem Investigation Process McGuire Nuclear Statio" Microfilm RollI F rame: I Closure Document Tvpe Closure Document No Attachments Generi c Applicability Responsible Gr oup: G-OEAGOPIPNo: Statu s: Closed ks t l{A issessmen e rna r: Siznutur e TyDC Indiv Team Group Dale Assigned To: G-OEADueD ate: 0113111990 Approved By: G-OEA 09/23/199 3 Failure Prevention InvestigationNoFPIRecords for thisPIP.RemarksNoRemark sforthisPIP.

Maintenance Rule N o Maintenance Rul e RecordsforthisPIP.End oftheDocumentforPIPNo:Thest atu softhi s PIP i s:ThedurationofthisPIPwas: M-87-208 Closed868days[Duration=StatusDate(0 1/3 1/l 990)-Discov eryDate(09116/l987

)](Note:AllCorrecti v e Actionswereprinted inthisrep ort.)OS/28/200810

39 Pa ge 4 PIP No: M-8 7-00208 Attachment 1 b Common Que stion 53 Page I of I.........The Post-e xam Item Analysis indicated that 7 of 12 applicants missed this question.*4 cho se"A"-clearl y wrongbecauset he MS IY sdonotfai l c lose d onloss ofYI*1 cho se"B"-clear l y wrongbecause theF RVs failed C L OSE D , not O PE N onloss of V I*2 chose" D"-plausible because thec harging flowvalve will fai l open and PZR level would eve ntua lly reachtherea ctor tr ip setpoin t.This distracteriswrong because the reactor will alreadybe tripped du e t oLoLo S/G levels pr ior to the PZR level reaching trip setpoint.N o applicant askedfor clarificationonthis ques t ion while takin g th e exa m.How did thi s question get through Validation?

Question53was revisedt o itsc urrent state around 2-26-08."C" distracter was validated onthe onthesimu lator where a loss of VId id r e sultinaF WP trip , turbinetrip, then r ea ctor tri p.Howe verwesimula tedacatastrophicbr eak on V I , where thepres sure dropped rapidly.Asa resulto f ourp o st-exam item analysis ,weranthes lowe r VIleakonthesimulator to more c loselyr e sembl e t he conditionsd e scri bed inth e question stem.That'swhen we realized thatt he FW P willn ot trip as describedonpa ge 1.During validation,six individuals took this vers ion of the que stion.*1 picked A*1 picked B*4 picked D Thevalidators admittedmemory decayon thefail ure mode ofva lves.Th er efore , we di d n'tqu e stion if"C" w as i n dee d c o rrec t.W e ha ve captur ed thi s le sson learned to ensure we validate written question scenariosonthesimulatorto more closely r e semble plant condition s in the question stem.

i----I'<'""NM'<tC C C C OJ OJ OJ OJ C/)C/)C/)C/).0.0.0.0 I!I o 0-0 M CI)>CI)...J I-0 0 I/)-N C'a I-CI)t: CI)o E 0 C'a 0 CI)N-(J)Q)E i=0 I/)......o o......o I/)o'<t o M o N o'<'"" o oI 2.9 065 AA2.08 1 1 Common 53 Tier#Group#KIA#Importance RatingRev.1tothe package (Ab ilitytodeterm ine and interpretthefollow ing a stheyapplytotheLossof Instrument A ir: Fa iluremodesofa ir-operated equipment)ProposedQuestion:BothUnitsareat100%

power when:*MNS experiencesalossofVI.*VI Headerpressureonbothunitsis30psigand continuestodecrease.WhichONE(1)ofthefollowingwillbeFIRSTtotripthe reactoranditsbasis?

A.OTDeltaTtripduetotheMSIVsfailingclosed.B.High-HighSGleveltripbecausethe FeedwaterRegValvesfailopen.C.TurbineTripduetoFeedPumpTripbecausethe FeedwaterRegValvesfailclosed.D.HighPzrLeveltripduetotheChargingFlowControlValvefailingopenwithLetdownisolated.ProposedAnswer:C Explanation (Optional):

A.Incorrect.IfMSIVsfailcloseditcouldcauseatriponLO-LOSGleveloronOTDTduetoTaverising

.FRVsfailingwillcausethetrip significantly fasterthanMSIVfailure.Plausiblebecauseuntilarecentmod

,theMSIVsdidfailcloseonalossofVI.

'".B.Incorrect.

Feedwaterregvalvesfailclosed,butplausiblebecausethisisthereactortrip mechanismiftheydidfailopen.

C.Correct.Reactortripwill occurduetoturbinetrip.If fedwaterregvalvesfailclosed,FeedPumpswilltriponhigh dischargepressure,wh ich directlycausesaturbinetrip.

D.Incorrect.Thiswouldcausea reactor trip ,butata significantlylatertime than feedwaterregvalvefailure.Chargingflowcontrolvalvefailsopenandletdownisolatesonlossofair,soPZRlevelwillberising TechnicalAP-22Background Reference(s)

Document(p22Rev12)

AP/1/A/5500/22 Enclosure12p104106,Rev27CF-CFp19Rev32 Proposed referencestobeprovidedto applicants during examination

LearningObjective
CF-CFObj4(Notechangesorattach parent)----Bank#ModifiedBank
  1. New X----QuestionSource
QuestionHistory:LastNRCExam

QuestionCognitive Level: Memory or Fundamental Knowledge ComprehensionorAnalysis X10CFRPart55 Content: 55.41 5 55.43 Comments:KAismatchedbecauseitem evaluatesthefailuremodeofairoperated equipmentthatw illcausea reactor tripRFA Concurs 4/24/08 Attachment la Common Question 53Page1 of8Afterfurther investigationweproposethatQuestion53bedeletedduetonocorrect answer.TheoriginalassumptionwasduetotheloweringVI(InstrumentAir)pressurethe S/Gfeedregvalveswouldfailclosedresultingin increasingfeedpumpdischargepressuretothepointwherethefeedpumpswouldtriponhighdischargepressure.Whilethefailure mechanismforthe FRV'siscorrectonaloss ofair(closed)

, the resultingReactortripoccursduetolow S/Glevelnotfeedpumpdischargepressure.Thiswasvalidatedonour simulatorwithaloss ofVIrampedinoveraperiod of5to10minuteswhichresultedinthereactortrippingonlow S/GlevelwhenVIpresshaddegradedtoapprox.40psig.WhileFWPdischarge pressuredidincrease,theaction oftheFWPcontrolsystemtomaintaintheprogram D IPatsetpointresultedinadecreaseinFWPspeedasthe FRV'sclosed.ThisactiondelaystheincreaseinFWPdischargepressure.tothepointwhere lowering S/GlevelwillreachtripsetpointpriortoincreasingFWPdischargepress.In4differentVIfailurescenarioswithvaryingleaksizesandramprates,thereactortrippeddueto S/GlevelpriortoFWPdischargepressreachingtripsetpoint.Thefeedpumpspeedcontrolsystemisdesignedto maintain a D IPsetpointbetweenMainSteamheaderpressureand FeedwaterHeaderpressure.Thissetpointisrampedfrom40psidat0%powerto175psidat100%power.(seepage5 ofthisattachment)WhenaVIsystemleakisinserted,the resultingloweringVI headerpresscausesthe FRV'stoslowlyclose.Astheyclose,FWPdischargepressincreases.Thiscausesthe SM/CF D IPtorapidlyincreaseandwasobservedtobeashighas400psid

.TheFWPcontrolsystemrespondstoslowtheFWPspeedinanattemptto maintain the programmed DIP.Ineverycaseexcepta catastrophicfailurewheretheVIheaderrapidly depressurizesthisaction significantlydelaystheincreaseinFWP dischargepressure.A catastrophic failure ofVIisnot consistentwiththeconditions establishedinthestem ofthisquestion

.Onefinaldatapointaddedtotheend ofthisattachmentiscopy ofPIPM87-00208whichdocumentsanactualloss ofVIin1987wherethereactortrippeddueto S/G LoLolevelafterapprox.5min

.Thisis consistentwithwhatweobservedduringour simulator validations.Question53asks,"WOOTFwillbetheFIRSTtotripthereactor".LoLo S/Glevelisnotlistedinany of the proposedanswers.Basedonthe informationaboveandthe attached documentation,wefeelthisquestionshouldbedeleteddueto havingnocorrect answer.

Attachment1b Common Question 53Page1 of 1 The Post-exam Item Analysis indicated that7of12 applicants missed this question.*4 chose"A"-clearl y wrong becausetheMSIVsdonotfailclosedonloss of VI*1chose"8"-clearlywrong becausetheFRVsfailedCLOSED

,notOPENonloss of VI*2chose"D"-plausible because th e charging flow valvewillfailopenandPZRlevelwoulde ventuallyreachthereactortripsetpoint.This distracteriswrongbecausethereactorwillalreadybetrippedduetoLoLoS

/OlevelspriortothePZRlevelreachingtripsetpoint.Noapplicantaskedfor clarificationonthisquestionwhiletakingtheexam

.How did this question get through Validation?Question53wasrevisedtoitscurrentstatearound2-26-08."C" distracter was validatedontheonthe simulatorwherealoss ofVIdidresultinaFWPtrip

,turbinetrip,thenreactortrip.Howeverwe simulated a catastrophicbreakonVI ,wherethepressuredroppedrapid ly.Asaresult of our post-examitemanalysis

,werantheslowerVIleakonthe simulator tomoreclosely resembletheconditionsdescribedinthequestionstem.

That'swhenwerealizedthattheFWPwillnottripa sdescribedonpage1.

During validation, six individuals took this version of the question.*1 picked A*1 picked 8*4 picked DThevalidatorsadmitted memorydecayonthefailuremode of valves.Therefore , we didn't question if"C"wasindeedcorrect.

We have capturedthislesson learned to ensure we validate written question scenarios on the simulator to more closely resemble plant conditions in the question stem.

Documentation of Post Exam Simulator Data for Common Question#53 The simulatorwasset up with a standard 100%MOC snap.A malfunction was inserted consisting of ramped 75%break of the Service Building VI (Instrument Air)header.Over the first30sec,VI pressure falls fairly rapidlytoa value of approximately 65 PSIG.At this point the FRV demand begins to increase indicating that the actual valve position is closing due to the lower VI header pressure.The result of the FRV's going closed shows that the FW header/Main Steam header DIP begins to increase due to the resulting increase in FWP discharge pressure.This resultsina control action by the FWPT Speed control system lower FWPT speed in an attempt to control the DIP at setpoint.These values are shown on the attached graph.At approx.65 psig the rateofVI pressure decrease slows which would be consistent with the automatic response of the standby VI compressors starting/loading attempting to restore VI pressure.Over the next 3 minutes, VI pressure continues to lower resulting in further closure of the FRV's thereby further reducingfeedflowto the S/G's.FWP discharge pressure continues to increase as the FRV's close but the FWPT control system is continuing to decrease the FWPT speed which dampens and slows this effect the to the point where the reductionoffeedflowto the S/G's resultsinalowlevel trip of the Reactor at 17%level approximately 4.5 minutes into the failure with VI pressure indicating about 30PSIG.Just prior to the trip, FWP discharge pressure peaks at approx.1400 PSIG whichiswell below the trip setpointof1435 PSIG.BelowI have pasted Excel Spreadsheet trends converted from the Simulator Data Recorder depicting the behavior of S/G level, FWP Discharge pressure, and VI Header pressure during the malfunction described above.TheXAxisis showing the Time in seconds.I have also attached anExcelfileto this communication with the raw data of the selected parameters and additional trends created from this data.

Steam Generator Level 70 60 50;;40->'"..J.9 e'" 30 c'" o E'"20 10 ,'I 50 100 150 200 2SO 300 3 a-10 TimeFWPTDischargePressure

-bsgnwl(1)

.bsgnwl(2)bsgnwl(3),-_.bsgnwl(4)ieoo I 1400 , , 1200 til 1000 til e c, s: (,)800-til 0 f-c,u, 600 400 200 a a50100150 Time200250300350 I-pet 5080**...pcf 5090 Inst.AirHdr.Press 120__.....-............, 100 iii 80 Ul e ll.Ql"0 co Ql J: 60 I-pvi 5060<1: '" E 2 10 40 E: 20 350 300 250 200 150 100 50 O!.----------------...,..--------l o Time Attachment 2 SRO Question 77 DuringthePostExamItemAnalysi swehave determined that Question77hastwo correctan swerswithDi st racter"C"beinga subset of the Correct Answer"0".Dueto thi s determin ation w e proposethatboth"C"and'0" be accept ed a s correct.Inthisquestion the candid ate is asked to determin ealeakratefromtheK C (Component Cooling)System.The operatorisgi ven KC surgetanklevelsforT=OandT-+5min alongwitha copy oftheKCSurgetanklevelcurv efromtheData Book.Correctly performed ,theleakrateis determinedtobe approximately100GPM.Alsointhestem of the question the operato r is advised t hat"Operato rshavebeen dispatched to initiateYM makeuptoth e KC surge t ank",butarenottoldthatthis makeup has actually been established.Theinitialle velinthe surgetank is6.5ft.The candidateisthen askedto d etermine"the required actionand procedure use r equiredinAP/2l , Loss ofKCorK C SystemLeakage".Per paragraph 7 of Appendix E of N UREG-I0 21page2 of 6 which is part of the briefing givenpr iortotheexam, the candidate saregiventhe following instructions,"When answeringaque stion,donotmake assumptions regarding conditionsthatarenot specifiedinthe question unless they occurasacon sequence of other conditionsthatare statedinth e question.Similarly,you shouldassumethatno operator action s have been taken , unless the stem oftheque stionorthean swer choices sp ecificallystate otherwise.Finally, answerallque stionsbasedon actual plant operation , procedure sorthe answer choices specifically stated otherwise".Withthi s d i rectioninm ind the candid ate can corr ectly assumethatYM makeupisnot initially align ed but within a reason able period oftimeitwillbe

.(Per the Time Critical Actions for our plant this should occur within10min of dispatch)Accordingtothe background documentforAP-21pg10 of23 ,"Per engineering

, YM makeup should be sufficienttokeepupwiththe FSAR design basi s l eak of50GPM".After d eterminin gthata100 GPMleakexists, even withYMmakeup aligned the candidate would r ea sonablycometoth e conclu sionthatKCsurget ank levelwould continue to decrea se.Procedurallyw e would alignthe Nuclear Service Wat er as sured makeup ifYM wasnot sufficientt okeepup withtheleakbutthe candidatesaretoldtonota ssume an y operator act ions not stated,ther eforeitisrea sonableforthe candidate to assumethat thishasnot andwillnot happen unle ss otherwise stated.Procedural guidanceperAP-21 direct sthatonceithasbeen determined that aleakexists operator s b e di sp atched earlyto initiateYMmak eupperStep 11.The procedure then checks surget ank le vel greaterthan3 ftwhichforthe scenario givenit shouldbefo r the fir st passthruth is step.The operator is t hen dire cted to check the"sum ofbothtrains'KCsurget ank le vel drop s LESS THANOREQ UALTO0.10 FT/MIN".If true,which fortheleakrate calculat ed, it wouldbe,thecre w i s directedtoSt ep 20 which will Isolat e "A" K C train f rom" B" K C tr ain.Thisactionisconsistent withtheactions statedinth e Correct answer" D" makingita validcorrectanswer.Onceagai n , a s sumin g n o operator actionha s taken place , thesurgetan klevelswill continuetod ecreaseuntilthey reach a l evel of 2 ft.Atthisp oint the"foldout" page would direct th e operatortoisolate the affectedtra inPEREne.2.Thisactio n i s statedinDi stracter"C" and sinc e thestemdoes n ot refer t o the"First" o r"Next" actiontaken, this action i s actually a subset o f" 0" and therefore a CO ITec t a nswer.Basedonthediscussion aboveandtheattachedreferences,werecommendth at both"C" and" 0" beaccepted as correctanswers.

.ES-401 A-+1 Hhrnl'r'ltPa ,j v 3SampleWrittenExaminationFormES-401-5 Question WorksheetExaminationOutline reference: Level RO SROProposedQuestion:SRO77 Tier#1----Group#1 KIA#(026)G2.1.25ImportanceRating 4.2----Page197 of271RevFinal

--..ES-401 Initial conditions:

Time=0 minutes Sample Written Examination Question Worksheet P OJ<'-'i Form ES-401-5*Unit1isat 100%power.*"A" Train KG pumps are running.*Operators have been dispatched to initiate YM makeuptotheKG Surge Tank.*"A"KG Surge Tanklevelis6.5 ft.*"B" KG Surge Tanklevelis6.5 ft.Current conditions:

Time=5 minutes*"A" KG Surge Tanklevelis5.6 feet*"B"KG Surge Tanklevelis6.4feet.

WhichONE(1)ofthe following describes(1)the approximate KC system netleakrate ,and(2)the required action and procedure use requiredinAP/21, LossofKGorKG System Leakage?(Reference Provided)A.B.G.D.(1)(2)(1)(2)(1)(2)(1)(2)50 GPM Isolate KC Non-Essential Headers in accordance with Enclosure 2.50GPM Isolate"A"KGtrainfrom"B"KCtrain.

100 GPM Isolate KG Non-Essential Headers in accordance with Enclosure 2.100 GPM Isolate"A"KGtrainfrom"B"KGtrain.

Proposed Answer: 0 Explanation (Optional):Page19 8 of271 Rev Final ES-401Sample Written Examination Question Worksheet PC\5 c 5 Form ES-401-5Dis correct per conditions.

Applicant must interpretcurveand determine theleakrate indicationsbasedonlevel decreases A incorrect becauseleakrateiswrong (1/2ofactual,as interpreted by curve.)Also , action is incorrect , as procedurewilld irect splittingtrainsfor indication shown B incorrect becauseleakrateis incorrect.

Plausible because action is correct C incorrect because procedure use i s incorrect.

Approximately 0.1 feet/minute

, performstep20tosplittrainsAP/21Step20Rev9 Technical Reference(s):(Attachifnot previously provided)-----------AP/21Basis DocumentRev3 Proposed referencestobe provided to applicants during examination:

OP/1lA/5100/22 Enclosure4.3Curve 7.31 Learning Objective:

Question Source: NoneBank#Modified Bank#New x (Note changesorattach parent)Question History: Question Cognitive Level:LastNRCExam Modified from 2007NRCexam 78 Memory or Fundamental Knowledge Comprehension or Analysis x10CFRPart5555.41 Content:55.435---Comments: KA matched becauseuseofacurveisrequiredand interpretation of that curve i s required to determineKC(CCW)leakrate

.SROlevel because assessment of Page 199of271 Rev Final

,.ES-401SampleWritten Examination Question WorksheetFormES-401-5 conditionsbasedon available indications,andselectionof procedures (attachments)isrequired RFA Concurs 4/17/08Page200 of271RevFinal 3.Foraninitialexamination

,thenominaltimelimitforcompletingtheexaminationis6hoursfortheROexam

3hoursforthe25-question

,SRO-onlyexam;8hoursforthecomb inedRO/SROexam;and4hoursfortheSROexamlimitedtofuelhandling.Notifytheproctorifyouneedmoretime.Forarequalificationexamination,thetimelim itforcomplet ingbothsect ionsoftheexaminationis3hours.Ifbothsectionsareadministeredinthesimulatorduringasingle3-hourperiod,youmayreturntoasectionoftheexaminationthatyoualreadycompletedorretainbothsectionsoftheexaminationuntiltheallottedtimehasexpired.

4.Youmaybringpens

,pencils,andcalculatorsintotheexaminationroom

however , programablememoriesmust be erased.Useblackinktoensure legible copies;darkpencilshouldbeusedonly ifnecessarytofacilitatemachinegrading

.5.Printyournameintheblankprovidedontheexaminationcoversheet andtheanswersheet.Youmaybeaskedtoprovidetheexaminerwithsomeformofpos itive identification.

6.Markyouranswersontheanswersheet provided ,anddonotleaveanyquestion blank.Useonlythepaperprovided.anddonotwriteonthebacksideofthepages

.Ifyouareusinginkanddecidetochangeyouroriginalanswer,drawasinglelinethroughtheerror,enterthedesiredanswer,and initialthechange.Ifyouare recording youranswersona machine-gradableformthatoffersmorethanfouranswerchoices(e.g.,"a"through"e"),becarefultomarkthecorrectcolumn.

7.Ifyouhaveanyquest ions concern ingtheintentortheinitialconditionsofaquestion

, do nothesitatetoaskthembeforeansweringthequestion.Notethatquestionsaskedduringtheexaminationaretakenintoconsiderationduringthegrad ing processandwhenreviewingapplicantappeals

.AskquestionsoftheNRCexaminerorthedesignatedfacility instructor only.Adictionaryisava ilableifyouneedit.Whenansweringaquestion,do notmakeassumptionsregardingconditionsthatarenotspecified inthequestionunlesstheyoccurasa consequenceofotherconditionsthatarestatedinthequestion

.Forexample

,youshouldnotassumethatanyalarmhasactivatedunlessthequest ionsostatesorthealarmisexpectedtoactivateasaresultoftheconditionsthatarestatedinthequestion

.Similarly,youshouldassumethatno operatoractionshave beentaken,unlessthestemofth e questionortheanswerchoicesspecificallystateotherwise

.Finally,answerallquestionsbasedonactualplantoperation,procedures,andreferences.Ifyoubelievethattheanswerwouldbe differentbasedonsimulatoroperationortrainingreferences,youshouldanswe rthequestionbasedonthe actual plant.8.Restroomtripsarepermitted,butonlyoneapplicantatatimewillbeallowedtoleave

.Avoidallcontactwithanyoneoutsidetheexaminationroomtoeliminateeventheappearanceor possibilityofcheating.AppendixE ,Page2of6 Information Only f+ttc.chml'/"\t

)..Paj G g Time Critical Operator Actions Information Only 17.Initiating makeup to the KC surge tank or isolate KC header leak Expectation

Operatorlocallyinitiatesmakeupwithin10 minutes of dispatch using eitherYMorRN,orgetsleak isolated prior to emptyingsurgetankfor designbasisleak of 50gpm.Follow-up planned: None.

References:

FSAR 9.2.4.3 PIP M98-3618 PIP M99-3778 AP/1/A/5500/21 (Loss ofKCorKCSystem Leakage)Comments: The FSAR requiredtimeto isolateaKCleakis30 minutes to prevent emptyingKCsurgetankfora50gpmleak.Ifmakeupcan stabilizesurgetanklevel, operation can continue with header in service until individual componentcanbeisolated.A10minutelocaltasktoinitiatemakeupis basedon:1)Timeto dispatch an operatorinAP/21,and2)

Ensuremarginto prevent reaching 2 ftinsurgetank(for50gpmleak).At2ft , AP/21 requires isolatingKCauxbldg non-essential header.This action has been validatedandtimes canbemet.18.Isolate letdown for a letdown header break: Expectation:

The FSAR assumes isolation of NY letdown within 30 minutes of a complete severance of a letdown headerintheauxbldg.

Operations expectationisthatleakwillbe isolatedassoonasitis identified.

Follow-up planned: None.

References:

FSAR 15.6.2.2 AP/1/A/5500/10 (NC System LeakageWithinthe Capacity of BothNYPumps)Comments: The limitingcasein FSARisa complete severance, at rated power conditions, ofthe3inch letdown line just outside containment, betweenNY-7Bandthe letdown heat exchanger.Page19 of 40

d..'iAP/1and2/Al5500/021 (Loss of KC or KC System Leakage)IfKCsurgetanklevel i s greaterthan3ft ,timeisgivenforthe operators to attempttoinitiatemakeupandcheckresultstoseeifthesurgetanklevelcanbe maintained.

Perengineering,YMmakeup shouldbe sufficienttokeepupwith the F SARdesignbasisleakof50G PM.Operatorsshouldbeabletoinitiatemakeuppriortoreaching2ftinthesurgetanks(assumingmakeupisinitiatedwhenKC 10levelalarmsat4.5ft).Ifthetrainsarecross-tied, allowingleavingthe cross-ties open doublesthevolume(andtime)toinitiatemakeup.Notethatforlargerleaks

,oriflevelreaches2ft,thecross-tieswillbeclosedto protecttheothertrain.Ifmakeupisinitiatedandlevelstabilizes, operatoractionsare greatly simplified.STEP16NOTES:

PURPOSE: Give operator information for determiningleakrate.DISCUSSION

0.1ft/minleveldropis equivalenttothedesignbasisleak(50gpm)thatYMmakeupshouldbeabletokeepupwith

.STEP16: PURPOSE:Procedureflowpathcontrollingstep.

DISCUSSION:Ifleakis greaterthandesignbasisleak, operatorsneedtofindtheleakandisolateit.Page10of23Rev3 A-\irY\('r,;)..P G5 c.I 0AP/1and 2/Al5500/021 (Loss of KC or KC System Leakage)INTRODUCTIONThisproceduregives guidanceontheactionsrequiredintheeventofalossofKG,orleakageontheKGSystem.

OVERVIEWOFAP-21AP-21iswrittenfor scenariosinvolvingalossofKG(likeKGpumptrips,etc.)andfor scenariosinvolvingKGleakage.For eithercase,theAPfirst addresses some immediateconcerns,likeisolatingletdownifnoKGpumps,makingplantpage,and securinganydilution.

For scenariosinvolvingalossofKGnotduetoleakage,theAP quickly attemptsstartingthestandbyKGtrain(Step9).ItistimecriticaltorestoreKGcoolingtoNGpumps (approx 10minutes).Ifcoolingisnotrestored,NGpumpsanda reactortripwillberequired.TheAPnext addresses scenariosinvolvingKGleakage.If KG leakage issmall(withindesign basis of50gpm)whenmakeupisinitiated,itshouldkeepupwiththeleakandavoid the processof header iso lations.Iftheleakistoobigformakeup

,thentheAPgoesthroughaprocessof header isolationsinapreferredord er.Inanycase,theAPendsupwithanessential headerinoperation,andintactnon-essheadersinservice.

ENTRY CONDITIONSThisprocedurecanbeenteredanytimethelisted symptoms are encountered.Page2of23Rev3 po I C c/"\,Ie MNSLOSSOFKCORKCSYSTEMLEAKAGEPAGENO.AP/1/A/5500/21Enclosure1-Page1of128of78 UNIT 1 Foldout Rev.91.KC header isolation criteria:*IFKCsurgetank levelgoesbelow 2 ft duetoKCsystemleak,THEN imme diatelyisolateaffectedtrainPEREnclosure2(Isolationof K C Non-essential Headers).2.NC pump trip criteria:*IFNCpumpmotorbearing temperaturereaches195°F,THENperformthefollowing

a.Tripthereactor

.b.WHENreactoristripped,THENtripallNCpumps.c.GOTOEP/1/A/5000/E-O (ReactorTriporSafetyInjection),whilecontinuinginthisprocedureastimeandconditionsallow

.3.ND pump trip and flow isolation criteria (Applies if ND aligned for RHR):*IFKCcoolinglosttoeitherNOtrain'sHX,ANDNC temperature is greaterthan150°F,THENperformthefollowingontrainofNOthatlostKCflowtoitsNOHX:

a.StopassociatedNOpump

.b.IF1ANOHXlostKCflow,THENclose:*1NO-33(ANOHxBypass)*1NO-32(ANOHxToLetdownHx).c.IF1BNOHXlostKCflow,THENclose:*1NO-18(BNOHxBypass)*1NO-17(BNOHxToLetdownHx)

.d.IFbothNOpumpsoffTHENREFERTO AP/1/A/5500/19(LossofNOorNOSystemLeak).4.KC pump trip criteria:*IFKCsurgetanklevelgoesbelow.5 ftandvalid,THEN:

a.Tripaffectedpumps

.b.IsolateaffectedtrainPEREnclosure2(IsolationofKC Non-essential Headers).5.VCT high temperature:*IF"VCTHITEMP"alarm(1AO-7

, 0-1)isreceived,THENREFERTOEnclosure6(VCTHigh Temperature Actions).

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