ML23206A041
| ML23206A041 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 08/02/2023 |
| From: | Southern Nuclear Operating Co |
| To: | Dawnmathews Kalathiveettil NRC/NRR/DORL/LPL2-1 |
| Kalathiveettil, D | |
| References | |
| EPID L-2023-LRM-0046 | |
| Download: ML23206A041 (1) | |
Text
EdwinI.HatchNuclearPlant RequestforLimitedExtensionofRiskInformed CompletionTime(RICT)ProgramBackstop
2 Agenda
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Agenda
Purpose:
EngageNRCStaffonSouthernNuclearsproposedchangetoextendthe RiskInformedCompletionTime(RICT)backstopforselectresidualheatremoval servicewater(RHRSW)andplantservicewater(PSW)TechnicalSpecification(TS)
RequiredActions(A.1-onepumpinoperable)
- SystemDesign
- CurrentTSRequirements
- BriefHistory
- RequestedChanges
- Approach
- Questions 3
4 SystemDesign
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- Twoindependentsubsystems
- Eachsubsystemhasasuctionsource(river),two50%(i.e.,4000gpm)capacitypumps, header,valves,piping,andheatexchanger
- Pumpapproximately12,000lbs /61ftlong;Motorapproximately7,600lbs /6ftlong
- SafetyanalysesassumeRHRSWsupportscoolingofthesuppressionpoolfollowing alossofcoolantaccident(LOCA)
- Safetyanalysesassumethat,withonesubsystemwithtwopumpsoperatingat3750 gpmeachandupto5%oftubespluggedinRHRheatexchanger,thesuppressionpool temperatureandprimarycontainmentpressurearelimited211.6°F(design 281°F) and 27.8psig(maximumallowable62psig),respectively
- PRASuccessCriteriaisonepumpat4000gpmandoneheatexchanger
[ML21300A153]
SystemDesign-RHRSW
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- Twoindependentsubsystems
- Eachsubsystemhasasuctionsource(river),two8500gpmcapacitypumps,header, valves,piping,andheatexchanger
- Threepumpsrequiredfornormaloperation;onepumprequiredforsafetyanalysis
- Pumpapproximately12,000lbs /61ftlong;Motorapproximately7,600lbs /6ftlong
- Safetyanalysesassumesystemsuppliescoolingtosafetyequipmentduring emergencyconditions
- ThedieselgeneratorsandthelongtermcoolingcapabilityoftheRHR,corespray,and RHRservicewaterpumpsdependonthecoolingprovidedbythePSWsystem.Either subsystemcanprovideadequatecoolingwithonlyonepumpprovidingflow.
- PRASuccessCriteria:onepumpat2400gpmandultimateheatsink
[ML21300A153]
SystemDesign-PSW
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7 Plantservicewaterpump
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RHRSW 8
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PSW 9
10 CurrentTSRequirements
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11 CurrentTSRequirements
12 ReasonforChange
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ReasonforChange
- Pumpreplacement typically710daysbut:
- Replacementpumpfailspreservicetest
- Needdiverstoinspectsuctionarea[+1day]
- Replacewith2nd replacementpump[+7to10days]
- Additionaldiscoveriesmadeduringpumpreplacement[+11days]
- Problemduringpostmaintenancetestrequiringoffsitemotorrefurbish[+7to10days]
- Preventivemaintenance(PM)toreplaceapumpmotoris45daysbut:
- Motor/pumpalignmentissue[+1day]
- Replacementpumpmotorrequiresoffsiteservicesandreinstall[+16days]
- Difficultiesaligningdischargeheadwithdischargecheckvalveflange[+10days]
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ReasonforChange November 2019 Unit 1 RHRSW pump B was replaced and then failed during pre-service testing. SNC replaced that pump with another new pump, which also failed during pre-service testing. SNC submitted an emergency license amendment request a to allow a one-time extension to the TS 3.7.1 Required Action A.1 Completion Time from 30 days to 45 days. The license amendment request was withdrawn b after the pump was restored to operable status less than 3 days prior to the original 30-day Completion Time.
September 2021 Challenges encountered during repair and replacement activities to restore operability to Unit 1 PSW pump C led to the need for an emergency license amendment request c (and RAI response d). The approved emergency license amendment e allowed, with compensatory measures established, a one-time extension of the TS 3.7.2 Required Action A.1 Completion Time from 30 days to 45 days.
April 2022 Challenges encountered during repair and replacement activities to restore operability to Unit 1 PSW pump A led to SNC submitting an emergency license amendment request f to, with compensatory measures established, extend the TS 3.7.2 Required Action A.1 Completion Time from 30 days to 45 days. The license amendment request was withdrawn g after HNP personnel restored the pump to operable condition less than 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> prior to the 30-day Completion Time.
- a. ML19333B967
- b. ML19336B596
- c. ML21264A003
- d. ML21266A004
- e. ML21264A644
- f. ML22120A087
- g. ML22123A159 14
15 RequestedChanges
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16 RequestedChanges
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17 RequestedChanges
18 Approach
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Approach-Justification(Technical/RiskBasis)
- Thecurrent30dayRICTbackstopisadministrativelimit
>> ProposedextensionislimitedtoCTswhereneedhasbeendemonstrated(TS3.7.1andTS3.7.2 RAA.1)
- TheRICTprogramprovidesassurancethattheplantismaintainedatanacceptablerisk level:
>> ConfigurationspecificCompletionTimes(willnotautomaticallyget45days)
>> RiskManagementActions
>> RICTBudgetandSNCproceduresencouragestayingwithinthefrontstopwhenpossible
- Safetyanalysisrequires:
>> OnePSWpumprequiredtosupplyforsafeshutdown,includingRHRshutdowncoolingsystem requirements
>> TwoRHRSWpumpsrequiredtoprovideadequateheatremovalcapacityfollowingadesignbasis LOCA.
- Wouldprecludeneedforanemergencyamendment maintainplantfocusonrestoring operability
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Approach-Justification(Precedence)
- CompletionTimesgreaterthan30daysarenotuncommon
>> SomePlantTechnicalSpecificationsExamples:
- HatchUnit1andUnit2TS3.7.4MainControlRoomEnvironmentalControl(MCREC)SystemRequired ActionB.3hasa90daycompletiontime.
- LimerickUnit1andUnit2TS3.7.1.2EmergencyServiceWaterSystem-CommonSystemActiona.1 allows45daystorestoreoperabilitywhenonepumpisinoperable.
- VogtleUnits1and2TS3.7.9UltimateHeatSink(UHS)RequiredActionD.2(restoreoperabilityto transferpump)hasa46dayCompletionTime.
- LaSalleUnits1and2TS3.7.3UltimateHeatSink(UHS)RequiredActionA.1(restoreoperabilitytocore standbycoolingsystempond)hasa90dayCompletionTime.
- ConsistentwithNUREG1433,CurrentHatchTS3.7.1andTS3.7.2allowcalculationofa RICTforonepumpinoperableineachsubsystem
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Approach Format
- SubmittalwillfollowpostTSTF505Adoption[ML20324A070]andNEI0602
- Attachmentstobeprovided:
1.
DescriptionandAssessment 2.
ProposedTechnicalSpecificationChanges(MarkUp) 3.
ProposedTechnicalSpecificationChanges(CleanTyped) 4.
ProposedTechnicalSpecificationBasesChanges(MarkUp)- ForInformationOnly
- Enclosuresintendedtobeprovided:
1.
ListofRequiredActionstoCorrespondingPRAFunctions 2.
InformationSupportingConsistencywithRegulatoryGuide1.200,Revision2 4.
InformationSupportingJustificationofExcludingSourcesofRiskNotAddressedbythePRAModels 5.
BaselineCDFandLERF 9.
KeyAssumptionsandSourcesofUncertainty
- 12. RiskManagementActionExamples
- Enclosuresnotintendedtobeprovided:
3.
InformationSupportingTechnicalAdequacyofPRAModelsWithoutPRAStandardsEndorsedbyRegulatoryGuide1.200,Revision2 6.
JustificationofApplicationofAtPowerPRAModestoShutdownModes 7.
PRAModelUpdateProcess 8.
AttributesoftheRealTimeModel
- 10. ProgramImplementation
- 11. MonitoringProgram
22 Questions