ML23355A194

Kairos Power LLC, Changes to Preliminary Safety Analysis Report (PSAR) Chapter 3 and Chapter 5

ML23355A194
Person / Time
Site:	Hermes  File:Kairos Power icon.png
Issue date:	12/21/2023
From:	Kairos Power
To:	Office of Nuclear Reactor Regulation
Shared Package
ML23355A192	List: ML23355A193 ML23355A194
References
KP-NRC-2312-003
Download: ML23355A194 (1)

Text

KP-NRC-2312-003 Changes to PSAR Chapter 3 and Chapter 5 (Non-Proprietary)

PreliminarySafetyAnalysisReport

DesignofStructures,Systems,andComponents

KairosPowerHermes2,Units1and2 35 Revision0 Table3.12:PrincipalDesignCriteria PrincipalDesignCriteria SARSection PDC1,QualityStandardsandRecords 3.5,4.3,6.3,7.3,7.4,7.5 PDC2,Designbasesforprotectionagainstnaturalphenomena 3.5,4.2.2,4.3,4.7,5.1,5.2,6.3,7.3,7.4, 7.5,8.2,8.3,9.1.1,9.1.2,9.1.3,9.1.4, 9.1.5,9.2,9.3,9.4,9.7,9.8.2,9.8.4, 9.8.5,11.2 PDC3,FireProtection 6.3,7.3,7.5,9.3,9.4 PDC4,Environmentalanddynamiceffectsdesignbases 4.2.2,4.3,4.7,6.3,7.3,9.1.1,9.1.2, 9.1.4,9.3,9.7,9.8.2,9.8.4,9.9 PDC5,Sharingofstructures,systems,andcomponents 3.1.1 PDC10,ReactorDesign 4.2.1,4.3,4.5,4.6,5.1,6.3,7.3 PDC11,ReactorInherentProtection 4.5 PDC12,Suppressionofreactorpoweroscillations 4.5,4.6,5.1 PDC13,InstrumentationandControl 7.2,7.3,7.5,9.1.3 PDC14,ReactorCoolantBoundary 4.3 PDC15,Reactorcoolantsystemdesign 7.3 PDC16,Containmentdesign 4.2.1,5.1 PDC17,ElectricPowersystems 8.2,8.3 PDC18,Inspectionandtestingofelectricpowersystems 8.2,8.3 PDC19,Controlroom 7.4 PDC20,Protectionsystemfunctions 7.3 PDC21,Protectionsystemreliabilityandtestability 7.3,7.5 PDC22,ProtectionSystemIndependence 7.3,7.5 PDC23,Protectionsystemfailuremodes 4.2.2,7.3 PDC24,Separationofprotectionandcontrolsystems 7.3,7.5 PDC25,Protectionsystemrequirementsforreactivitycontrol malfunctions 7.3

PreliminarySafetyAnalysisReport

DesignofStructures,Systems,andComponents

KairosPowerHermes2,Units1and2 36 Revision0 PrincipalDesignCriteria SARSection PDC26,Reactivitycontrolsystems 4.2.2,4.5 PDC28,Reactivitylimits 4.2.2,7.3 PDC29,Protectionagainstanticipatedoperationoccurrences 4.2.2,7.3,7.5 PDC30,Qualityofreactorcoolantboundary 4.3 PDC31,Fracturepreventionofreactorcoolantboundary 4.3 PDC32,Inspectionofreactorcoolantboundary 4.3 PDC33,Reactorcoolantinventorymaintenance 4.3,5.1,9.1.4,9.3 PDC34,Residualheatremoval 4.3,4.6,6.3 PDC35,Passiveresidualheatremoval 4.3,4.6,6.3 PDC36,Inspectionofpassiveresidualheatremovalsystem 4.3,6.3 PDC37,Testingofpassiveresidualheatremovalsystem 4.3,6.3 PDC44,Structuralandequipmentcooling 9.1.5,9.7 PDC45,Inspectionofstructuralandequipmentcoolingsystems 9.1.5,9.7 PDC46,Testingofstructuralandequipmentcoolingsystems 9.1.5,9.7 PDC60,Controlofreleasesofradioactivematerialstothe environment 5.1,5.2,9.1.3,9.2,9.9.1,9.9.3,11.2 PDC61,Fuelstorageandhandlingandradioactivitycontrol 9.3 PDC62,Preventionofcriticalityinfuelstorageandhandling 9.3 PDC63,Monitoringfuelandwastestorage 9.3,11.2 PDC64,Monitoringradioactivityreleases 5.2,9.1.2,9.1.3,9.2,9.9.1,9.9.3 PDC70,Reactorcoolantpuritycontrol 5.1,9.1.1,9.1.4 PDC71,Reactorcoolantheatingsystems 9.1.5 PDC73,Reactorcoolantsysteminterfaces 5.2

PreliminarySafetyAnalysisReport

DesignofStructures,Systems,andComponents

KairosPowerHermes2,Units1and2 337 Revision0 SSCName Safety Classification SeismicDesign QualityProgram SARSection PlantArea IntermediateHeatExchanger Nonsafetyrelated LocalBuilding Code NotQualityRelated 5.1.1 SRarea PrimaryLoopPipingSystem Nonsafetyrelated LocalBuilding Code NotQualityRelated 5.1.1 SRarea PrimaryLoopThermal Management Nonsafetyrelated LocalBuilding Code NotQualityRelated 5.1.1 SRarea ReactorCoolant Safetyrelated N/A QualityRelated 5.1.1 SRarea AntiSiphonFeature Safetyrelated SDC3 QualityRelated 5.1.1 SRarea IntermediateHeatTransportSystem IntermediateSaltPumps Nonsafetyrelated LocalBuilding Code NotQualityRelated 5.2 NSRarea IntermediatePipingSystem Nonsafetyrelated LocalBuilding Code NotQualityRelated 5.2 SRandNSRarea Superheater Nonsafetyrelated LocalBuilding Code NotQualityRelated 5.2 NSRarea IntermediateLoopAuxiliary HeatingSubsystem Nonsafetyrelated LocalBuilding Code NotQualityRelated 5.2 SRandNSRarea IntermediateInertGas Subsystem Nonsafetyrelated LocalBuilding Code NotQualityRelated 5.2 SRandNSRarea IntermediateCoolant InventoryManagement Subsystem Nonsafetyrelated LocalBuilding Code NotQualityRelated 5.2 SRandNSRarea IntermediateCoolant, ChemistryControlSubsystem Nonsafetyrelated LocalBuilding Code NotQualityRelated 5.2 SRandNSRarea IntermediateCoolant Nonsafetyrelated N/A NotQualityRelated 5.2 SRandNSRarea

Preliminary Safety Analysis Report Heat Transport Systems Kairos Power Hermes 2 Unit 1 and 2 5-9 Revision 0 5.2 INTERMEDIATE HEAT TRANSPORT SYSTEM 5.2.1 Description The Intermediate Heat Transport System (IHTS) transfers heat from the PHTS (Section 5.1) by circulating intermediate coolant between the cooling side of the IHX and the power generation systems (Section 9.9) during normal plant operation. The IHTS includes intermediate salt pumps (ISPs), intermediate salt vessels (ISVs), a superheater, and associated piping. The IHTS transports tritium from the IHX to the tritium management system (TMS) in the cover gas portion of the ISVs. The TMS is described in Section 9.1.3. The IHTS also provides for fill/draining control of the IHTS piping, IHX, and superheater tube side.

The information presented in this section is applicable to both Unit 1 and Unit 2. Each unit has its own IHTS and there are no shared IHTS components between units. A process flow diagram of the IHTS showing both units is provided in Figure 5.1-1. The key design parameters for the IHTS are provided in Table 5.2-1.

The primary system functions of the IHTS are non-safety related and include the following:

Transport heat from the PHTS to the steam system.

Manage thermal transients (overall thermal balance) occurring as part of normal operations.

Maintain intermediate coolant pressure below primary coolant pressure within the IHX.

Facilitate tritium transfer from the intermediate coolant to the TMS to capture tritium permeating into the IHTS.

There is one safety-related function associated with the IHTS:

Relieve IHTS pressure in the event of a superheater tube leak or rupture event.

The design of the IHTS allows for on-line monitoring, in-service inspection, maintenance, and coolant replacement activities. The primary components of the IHTS are described in the following subsections.

5.2.1.1 Intermediate Coolant Inventory Management Subsystem The intermediate coolant inventory management subsystem maintains the total intermediate coolant inventory in the IHTS above a minimum volume and manages the volume of intermediate coolant within the various components of the IHTS. The ISVs within the intermediate coolant inventory management subsystem store surplus intermediate coolant inventory and support system filling and draining during startup and normal shutdown conditions. The ISVs accommodate thermal expansion of the intermediate coolant.

The intermediate coolant inventory management subsystem includes the functionality to melt new intermediate coolant for addition via the ISVs, and to solidify used intermediate coolant after removal from the ISVs.

5.2.1.2 Intermediate Inert Gas Subsystem The IHTS design includes an intermediate inert gas subsystem to control intermediate coolant chemistry, to minimize corrosion, and to control and recover tritium. Inert gas within the ISVs is circulated through the TMS to capture tritium in the gas (see Section 9.1.3). Gas composition and impurities within the ISVs inert gas are controlled to maintain conditions which facilitate tritium capture. The intermediate inert gas subsystem is designed to support keeping the intermediate coolant pressure in the heat exchangers lower than the pressure in the PHTS.

Preliminary Safety Analysis Report Heat Transport Systems Kairos Power Hermes 2 Unit 1 and 2 5-10 Revision 0 The IHTS is equipped with safety-related rupture disks located in the intermediate inert gas subsystem, made of austenitic stainless steel, which prevents overpressure in the IHTS during a postulated superheater tube leak or rupture event.

5.2.1.3 Intermediate Coolant The intermediate coolant is a eutectic mixture of sodium fluoride and beryllium fluoride (57mol%NaF-43mol%BeF2, referred to as BeNaF). BeNaF has similar characteristics to Flibe in that it is thermodynamically stable, is compatible with structural materials, and has analogous chemical properties to the primary Flibe coolant.

5.2.1.4 Intermediate Coolant Chemistry Control Subsystem The intermediate coolant chemistry control subsystem supports monitoring and control of intermediate coolant chemistry. The intermediate coolant inventory management subsystem may be used to remove and replace a sufficient amount of intermediate coolant to control intermediate coolant chemistry.

5.2.1.5 Intermediate Salt Pumps The ISPs provide the motive force for the circulation of intermediate coolant between the IHX and the superheater, and provide the needed pressure and flow rate in the IHTS. The intermediate coolant is circulated through the superheater where heat is transferred to saturated steam to produce superheated steam in the power generation systems (see Section 9.9).

The IHTS is equipped with safety-related rupture disks located in the intermediate inert gas system, made of austenitic stainless steel, which prevents overpressure in the IHTS during a postulated superheater tube leak or rupture event.

5.2.1.6 Intermediate Piping The intermediate piping serves as the flow conduit within the IHTS. The design of the piping accommodates continuous operation at full thermal power and operates under partial load conditions at reduced flow rate.

The design of the IHTS piping includes provisions for filling, draining, and high point venting, and accommodates thermal expansion between the ISPs, the ISVs, and the superheater.

5.2.1.7 Intermediate Loop Auxiliary Heating Subsystem The IHTS contains an auxiliary heating subsystem to provide non-nuclear heating as needed for plant startup, shutdown, and supplemental heating during normal operation. The auxiliary heating maintains the IHTS piping at or above the trace heating setpoint temperature. The source of the heat depends on the subsystem or component requiring the heat. The selected heat source will be described in the application for an Operating License.

5.2.2 Design Basis Consistent with PDC 2, the safety-related SSCs located near the IHTS are protected from the adverse effects of postulated IHTS failures during a design basis earthquake.

Consistent with PDC 60, the IHTS includes features that support the control of radioactive materials during normal reactor operation.

Consistent with PDC 64, the IHTS is designed to monitor radioactive releases.

PreliminarySafetyAnalysisReport

HeatTransportSystems

KairosPowerHermes2Unit1and2 511 Revision0 ConsistentwithPDC73,theIHTSincludesapassivebarrier(IHX)forthereactorcoolantsystemthatis chemicallycompatiblewiththeIHTScoolantandIHTSfeaturesthatsupportthecontrolofradioactive materialsduringnormalreactoroperation.TheIHTSprovidestwopassivebarriers(IHXandsuperheater) betweenFlibeinthePHTSandsteaminthesteamsystem.

Consistentwith10CFR20.1406,theIHTSisdesigned,totheextentpracticable,tominimize contaminationofthefacilityandtheenvironment,andtofacilitateeventualdecommissioning.

5.2.3 SystemEvaluation ThedesignoftheIHTSissuchthatafailureofcomponentsoftheIHTSdoesnotaffecttheperformance ofsafetyrelatedSSCsduetoadesignbasisearthquake.ThosesafetyrelatedSSCswillbeprotected fromseismicallyinducedfailuresoftheIHTSbyeitherseismicallymountingtheapplicablecomponents, confirmingsufficientphysicalseparation,orbytheerectionofbarrierstoprecludeadverseinteractions.

Also,theIHTSislocatedinsafetyrelatedandnonsafetyrelatedportionsoftheReactorBuilding.Asa result,portionsoftheIHTSmaycrosstheisolationmoatdiscussedinSection3.5.SSCsthatcrossthe baseisolationmoatmayexperiencedifferentialdisplacementsasaresultofseismicevents.TheIHTSis designedsothatpostulatedfailuresofSSCsinthesystemfromdifferentialdisplacementsdonot precludesafetyrelatedSSCsfromperformingtheirsafetyfunction.Designfeaturesaddressing differentialdisplacementarediscussedinSection3.5.ThissatisfiestherequirementsofPDC2forthe IHTS.

Tritiumwillbepresentintheintermediatecoolantaspartofnormaloperationsoftheplant.Control measureswillbetakentominimizethereleaseofradioactivematerialandensurethatitisalsobelow allowablelimits.TritiumwhichpermeatesthroughtheIHXheattransfersurfaceisexpectedtoenterthe intermediatecoolantinthechemicalformofHTorT2.AsdescribedinSection9.1.3,anhydrous hydrogenfluoridewillbeaddedtotheintermediateinertgassystemtoconvertthetritiumtoatritium fluoridethatwillmoveintothegasspaceoftheISVs.TheTMSwillcapturetritiumfromthegasmixture.

RemovaloftritiumfromtheISVgasspacesreducestritiuminventorythatisavailableforrelease,as describedinSection9.1.3.PostulatedfailuresoftheIHTScouldcauseintermediatecoolantorcovergas toleakintothereactorbuilding.SucheventsareevaluatedinSection13.1.Thesefeaturesdemonstrate conformancewiththerequirementsinPDC60.

RadiationmonitoringisprovidedintheISVcovergasspacefortheevaluationofradioactivitylevelsin thegas.Thismonitoringsupportstheevaluationoftheradioactivematerialreleasesthatmightoccuras aresultofasystemfailure.Thisdesignfeature,inpart,satisfiesPDC64.

TheIHTScoolanthasthepotentialtobecontaminatedwithFlibeduetoapostulatedleakoftheIHX,as theFlibeismaintainedatahigherpressurethantheintermediatecoolant.However,thetwofluidsare chemicallycompatible.Flibeisseparatedfromthewaterinthepowergenerationsystembytwopassive barriers,theIHXandsuperheaterboundaries.TheIHTSisprovidedwithsafetyrelatedrupturedisksto mitigatetheeffectsofapostulatedsuperheatertubeleakortuberuptureevent.Thesefeatures demonstrateconformancewiththerequirementsinPDC73.

TheIHTSpipingisdesignedtotheASMEB31.3Code.ThesuperheaterisdesignedtoASMEBPVCSection VIII.TheISVsaredesignedtoASMEBPVCSectionVIII.TheIHTScoolanthasthepotentialtobe contaminatedwithtritiumorotherradioactivematerialsinapostulatedleakfromthePHTSintothe IHTS,viatheIHX.Assuch,theIHTSincludesfeaturesthatsupportmonitoringradioactivematerial releasesfrombreaksandleaksinthepipingsystemorviapressurereliefequipment.Therefore,the designofthesystemminimizescontaminationandsupportseventualdecommissioning,consistentwith therequirementsof10CFR20.1406,asdescribedinChapter11.