ML22230D065
| ML22230D065 | |
| Person / Time | |
|---|---|
| Site: | Hermes File:Kairos Power icon.png |
| Issue date: | 08/18/2022 |
| From: | Kairos Power |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML22230D063 | List: |
| References | |
| KP-NRC-2208-004 | |
| Download: ML22230D065 (3) | |
Text
KPNRC2208004
ChangestoPSARChapter4 (NonProprietary)
PreliminarySafetyAnalysisReport
ReactorDescription
KairosPowerHermesReactor
Revision0 443 Condition1,theshutdownandcontrolelementsprovideameanstoensurethatSARRDLsarenot exceeded,andthatsafeshutdownisachievedandmaintainedduringnormaloperation.Condition1is metassumingthehighestworthshutdownorcontrolelementisfullywithdrawn.Incompliancewith Condition2ofPDC26,thecontrolelementsbythemselvesprovidethecapabilitytocontrolreactivity changesduringplannednormalpowerchangessuchthattheSARRDLsarenotexceeded.Thecontrol elementsprovideameansthatisindependentanddiversefromtheshutdownelementsbecausethey arelocatedindifferentlocations,receivedifferentsignalstotrip,andeachofthemhavetwo independentanddiversereleasemechanisms.IncompliancewithCondition3ofPDC26,theshutdown andcontrolelementsprovideameansofinsertingreactivityatasufficientrateandamount,toensure thatthecapabilitytocoolthecoreismaintainedandameansforshuttingdownthereactorand maintainingitatsafeshutdownfollowingapostulatedevent.Condition3ismetassumingthatthemost reactivecontrolorshutdownelementisfullywithdrawn.IncompliancewithCondition4ofPDC26,the shutdownandcontrolelementsprovideameansformaintainingthereactorshutdowntoallowfor interventionssuchasfuelloading,inspection,andrepair.CompliancewithPDC26issummarizedin Table4.56.
NuclearStability Theinherentnuclearcharacteristicsofthereactoraresuchthatuncontrolledpoweroscillationsarenot possible.Thereactorissmallinsizeandisneutronicallyconnectedduetothelongdiffusionlengthof neutronsinthecore.Asaresult,thereactorisinherentlystablewithregardtobothaxialandradial poweroscillations.IncompliancewithPDC12,thereactorisnotsusceptibletonuclearinstability.
4.5.3.2 NuclearDesignAnalysisInputstoOtherSections VesselIrradiation Thefastneutronfluencereceivedbythereactorvesselfromthereactorcoreandpebbleinsertionand extractionlinesisattenuatedbythecorebarrel,thereflector,andbythereactorcoolant.Fluenceand depletioncalculationsareperformedtoconfirmthatthevesselisnotadverselyaffectedbythisneutron fluence.Themethodologyforcalculatingbestestimatevesselfluenceandheliumproductionassociated transmutationproductsisdescribedinReference1.Thesecalculatedvaluesareevaluatedusing conservativeuncertainties.
Thecalculationofassociateddpaonthevesselusesthefluenceasinput.Thepreliminarybestestimate dpaplusuncertaintyiswithin30%ofthelowlevelirradiationvaluediscussedinReference2.
NuclearTransientAnalysis Valuesforneutrongenerationtimeanddelayedneutronfractionareshownduringstartupand equilibriumoperationinTable4.57.Inaddition,conservativevaluesforpowerdistribution,reactivity coefficients,andshutdownmarginareprovidedfortheinitialconditionsforeachofthepostulated reactivitytransienteventsanalyzedinChapter13.
Themostcredibleinadvertentinsertionofexcessreactivitydoesnotdisturbthecoreanddoesnot adverselyimpactthecapabilitytocoolthecoreinaccordancewithPDC28asdescribedinChapter13.
4.5.4 CoreDesignLimits 4.5.4.1 NuclearCoreDesignLimits Thereactorcoredesignisperformedsuchthatthedesignparametersduringnormaloperationare withinthefuelqualificationenvelopedescribedinSection4.2.1forpeakparticlepower,burnup,peak fluence,andpeakfueltemperature.
PreliminarySafetyAnalysisReport
ReactorDescription
KairosPowerHermesReactor
Revision0 444 4.5.4.2 TestingandMonitoring Neutronfluxandburnuparemonitoredduringoperationtoensurethatthecoreisperformingwithin design.
Thefollowingcorenucleardesignparametersareanticipatedtobeincludedinthetechnical specifications:
ShutdownMargin CoolantOutletTemperature Moderatorpebbletofuelpebbleratio Therewillalsobeatechnicalspecificationcontrollingthefuelenrichmenttolessthan20wt%U235.
ThetechnicalspecificationsaredescribedinChapter14.
4.5.5 References
- 1. KairosPowerLLC,KPFHRCoreDesignandAnalysisMethodology,KPTR017P,September2021.
- 2. KairosPower,LLC,MetallicMaterialsQualificationfortheKairosPowerFluorideSaltCooledHigh TemperatureReactor,KPTR013P,Revision3.