ML24122C615

LLC, Response to NRC Request for Additional Information No. 005 (RAI-10089-R1) on the NuScale Standard Design Approval Application

ML24122C615
Person / Time
Site:	05200050, 99902078
Issue date:	05/01/2024
From:	Shaver M NuScale
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
RAIO-157505
Download: ML24122C615 (1)

Text

RAIO-157505

May 01, 2024 Docket No.52-050

U.S. Nuclear Regulatory Commission ATTN: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852-2738

SUBJECT:

NuScale Power, LLC Response to NRC Request for Additional Information No. 005 (RAI-10089-R1) on the NuScale Standard Design Approval Application

REFERENCE:

NRC Letter to NuScale, Request for Additional Information No. 005 (RAI-10089-R1), dated October 18, 2023

The purpose of this letter is to provide the NuScale Power, LLC (NuScale) response to the referenced NRC Request for Additional Information (RAI).

The enclosure to this letter contains the NuScale responses to the following RAI questions from NRC RAI-10089:

9.2.2-1 9.2.3-1

This letter makes no regulatory commitments and no revisions to any existing regulatory commitments.

If you have any questions, please contact Jim Osborn at 541-360-0693 or at josborn@nuscalepower.com.

I declare under penalty of perjury that the foregoing is true and correct. Executed on May 01, 2024.

Sincerely,

Mark W. Shaver Director, Regulatory Affairs NuScale Power, LLC

Distribution: Mahmoud Jardaneh, NRC Getachew Tesfaye, NRC Greg Cranston, NRC

NuScale Response to NRC Request for Additional Information RAI-10089, nonproprietary

NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvallis, Oregon 97330 Office 541.360.0500 Fax 541.207.3928 www.nuscalepower.com RAIO-157505

NuScale Response to NRC Request for Additional Information RAI-10089, nonproprietary

NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvallis, Oregon 97330 Office 541.360.0500 Fax 541.207.3928 www.nuscalepower.com NuScaleNonproprietary

ResponsetoRequestforAdditionalInformation Docket:052000050

RAINo.:10089 DateofRAIIssue:10/18/2023

NRCQuestionNo.:9.2.2-1

REGULATORYREQUIREMENT ContentofApplication;TechnicalInformation,10CFR52.137(a)(2)states,inpart,with regardstothesystems,structures,andcomponents(SSCs),thatthedescriptionshallbe sufficienttopermitunderstandingofthesystemdesignandtheirrelationshiptothesafety evaluation.

ISSUE ThestaffreviewedtheinformationprovidedintheFSARinPart2,Section9.2.2,Reactor ComponentCoolingWaterSystem,(RCCWS)anddeterminedthatitdoesnotfullysatisfythe regulatoryrequirementbecauseitdoesnotcontainsufficientinformationnecessarytoobtainan understandingofthefunctionalsystemdesignandoperation,nordoesitcontainanyschematic ordrawingsthatshowthefunctionalarrangement.Specifically,Section9.2.2doesnotcontain sufficientinformationonthesystemdesign,configuration,andoperationtoallowthestaffto concludethatsystemfailurewillnotadverselyaffectplantsafetyorradiologicalreleasefromthe plantduringnormaloperation.

Additionally,theFSARhasincludednoinformationonthesystemoperatingparameters(i.e.,

flows,temperatures,andpressures)duringnormaloperation,ortheabilitytoisolatethesystem ifthereisafailureinpartofthesystem,eitherspecifictoonemoduleorcommontoallmodules.

TherelevantrequirementsoftheCommissionsregulationsforthisareaofreview,andthe associatedacceptancecriteria,aregiveninStandardReviewPlan(SRP)Section9.2.2, Revision4,ReactorAuxiliaryCoolingWaterSystem,issuedMarch2007.Therequirements includethefollowing:

• GeneralDesignCriterion(GDC)2,Designbasesforprotectionagainstnaturalphenomena, asitrelatestothecapabilityofstructureshousingthesystemandthesystemitselftowithstand theeffectsofnaturalphenomenasuchasearthquakes,tornadoes,hurricanes,floods,tsunami, andseicheswithoutalossofsafety-relatedfunctions.

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• GDC4,Environmentalanddynamiceffectsdesignbases,asitrelatestothecapabilityofthe systemandthestructurehousingthesystemtowithstandtheeffectsofmissilesinsideand outsideofcontainment,theeffectsofpipewhipandjets,environmentalconditionsfromhigh-andmoderate-energylinebreaks,andthedynamiceffectsofflowinstabilitiesandloads(e.g.,

waterhammer)duringnormalplantoperationandupsetoraccidentconditions.

• GDC60,ControlofReleasesofRadioactiveMaterialstotheEnvironment,asitrelatestothe turbineglandsealingsystemdesignforthecontrolofreleasesofradioactivematerialstothe environment.

• GDC64,MonitoringRadioactivityReleases,asitrelatestotheturbineglandsealing systemdesignformonitoringreleasesofradioactivematerialstotheenvironmentduring normaloperation,includinganticipatedoperationaloccurrences.

• 10CFR20.1406,MinimizationofContamination,asitrelatestothedesignfeaturesthat willfacilitateeventualdecommissioningandminimize,totheextentpracticable,the contaminationofthefacilityandtheenvironmentandthegenerationofradioactivewaste.

Also,GDC26requiresReactivitycontrolsystemredundancyandcapability.Specifically,two independentreactivitycontrolsystemsofdifferentdesignprinciplesshallbeprovided.Oneof thesystemsshallusecontrolrods,preferablyincludingapositivemeansforinsertingtherods, andshallbecapableofreliablycontrollingreactivitychangestoassurethat,underconditionsof normaloperation,includinganticipatedoperationaloccurrences(AOOs),andwithappropriate marginformalfunctionssuchasstuckrods,specifiedacceptablefueldesignlimitsarenot exceeded.Therefore,althoughthenon-safetyrelatedRCCWSisnotrequiredforsafe shutdown,itsoperationisnecessarytoassurethatthecontrolroddrivesystemmeetsthe requirementsofGDC26forreliablycontrollingreactivitychangesunderconditionsofnormal operation,includingAOOs.

ForthestafftoperformthereviewoftheRCCWS,itisnecessarythatthesystemlocation, generalconfiguration,andperformanceanddesignparametersbeincludedinthedesign description.Inorderforthestafftounderstandthesystemdesignanditsrelationshiptoplant safety,FSARSection9.2.2mustprovideadescriptionofthesystemconfigurationincluding applicableschematicdiagramsthatidentifysystemboundariesandinterfaces,alongwith designandperformancedata,thatidentifiesthenormaloperatingparametersforthesystem includingflow,pressure,temperature,etc.Theabilitytoisolatethesystemorportionsofthe systemintheeventthatintersystemleakageisdetectedorifthereisabreakinaRCCWSpipe insidethereactorcontainmentorthereactorbuildingshouldalsobediscussedintheFSAR.

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FSARSection9.2.2doesnotcontainsufficientinformationonthesystemdesign,configuration, andoperationtoallowthestafftoconcludethatsystemfailurewillnotadverselyaffectplant safetyorradiologicalreleasefromtheplantduringnormaloperation.

REQUESTEDINFORMATION ThestaffrequeststhatNuScaleprovideandincludeinSection9.2oftheFSARthefollowing information:

1.ARCCWSschematicthatwillallowthestafftoreviewanddetermine,inaccordancewith GDCs2and4,thatfailureofRCCWSSSCsinthereactorbuildingorwhichpassthrough containmentwillnotdamageotherSSCsimportantsafetyduetopipewhip,flooding,orother effects.AsimilarschematicwasincludedinFSARSection9.2.2ofthedesigncertification FSAR.

2.Designinformationonsafetyandseismicdesigncategorization,inaccordancewithGDC2, fortheSSCsthatpenetratethecontainmentandareincloseproximitytothereactor(RCCWS supplyandreturntoandfromthecontrolroddrivemechanisms(CRDMs)).

3.InformationontheRCCWSheatremovalcapacityanddemandrequirements,suchasforthe CRDMs,duringnormaloperation(notethatGDC26requirescontrolroddrivestobeoperable duringAOOs).

4.Inaccordancewith10CFR20.1406,informationonhowthesystemprovidesadequate radiationmonitoringtoindicatein-leakagetothesystemfromacontaminatedsystemthatit interfaceswith,howthesystemisdesignedsothatleakagefromthesystemcanbedetected, andhowappropriatesystemisolationcanbeinitiated.

5.Systemdesigninformationonleakagedetectionfromthesystemandhowitprovidesfor isolationtocomplywiththerequirementsofGDC60and64astheyrelatetocontrolofreleases ofradioactivematerialstotheenvironmentandmonitoringradioactivityreleases.

NuScaleResponse:

ContentofApplication;TechnicalInformation,10CFR52.137(a)(2)requires,

A descriptionandanalysisoftheSSCsofthefacility,withemphasisuponperformance requirements,thebases,withtechnicaljustification,uponwhichtherequirementshavebeen established,andtheevaluationsrequiredtoshowthatsafetyfunctionswillbeaccomplished.It isexpectedthatthestandardplantwillreflectthroughitsdesign,construction,andoperationan extremelylowprobabilityforaccidentsthatcouldresultinthereleaseofsignificantquantitiesof radioactivefissionproducts.Thedescriptionshallbesufficienttopermitunderstandingof

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thesystemdesignsandtheirrelationshiptothesafetyevaluations.Itemssuchasthe reactorcore,reactorcoolantsystem,instrumentationandcontrolsystems,electricalsystems, containmentsystem,otherengineeredsafetyfeatures,auxiliaryandemergencysystems,power conversionsystems,radioactivewastehandlingsystems,andfuelhandlingsystemsshallbe discussedinsofarastheyarepertinent.

Thereactorcomponentcoolingwatersystem(RCCWS)doesnotperformsafetyrelatedorrisk significantfunctions.Inaccordancewith10CFR52.137(a)(2),NuScalespositionisthatthereis sufficientdescriptionforunderstandingofthesystemdesignandtherelationshiptothesafety evaluation.Furthermore,thepertinentregulationsfortheRCCWSaresufficientlydescribedin SDAAFSARsection9.2.2,orothersections,asdescribedbelow.

Citingasub-partof10CFR52.137(a)(2)astheregulatoryrequirementforanRAIisnon-specificanddoesnotprovideanunderstandingofthespecificinformationmissinginthe application.ThedescriptionprovidedintheIssuesectionoftheRAIisspecific,providesan adequatebasisforunderstandingtheNRCissue,andNuScalehasprovidedresponsestothe individualconcernslistedbelow:

1.AsystemschematicdoesnotprovideinformationrelatedtoGDC2orGDC4.TheRCCWSis locatedintheReactorBuilding,whichisaSeismicCategoryIstructuredesignedtoprotect componentsfromextremewindsandmissilesthatmayresultfromnaturalphenomenasuchas earthquakes,tornadoes,andhurricanes.TheReactorBuildingalsoprotectscomponentsfrom theeffectsofexternalflooding,asdescribedinSection3.4.SDATable9.2.2-1:Classificationof Structures,Systems,andComponentsprovidestheseismicclassificationoftheRCCWS structures,systemsandcomponents(SSC).Table9.2.2-1,Note4andSection9.2.2.3explain thatcomponentsoftheRCCWSthatcouldadverselyaffectSeismicCategoryISSCare categorizedasSeismicCategoryII.Section3.6,ProtectionagainstDynamicEffectsAssociated withPostulatedRuptureofPiping,containsinformationaboutpipewhipandfloodingwith respecttoRCCWS,includingcompliancewithGDC4.Thereactorcomponentcoolingwater system(RCCWS)supplyandreturnlinesarepartofthecontrolroddrivesystem(CRDS)inside thecontainment.TheRCCWSsupplyandreturnlinesaremoderateenergy.Theeffectsof leakagecracksinthemoderate-energyRCCWSlinesareboundedbybreaksinhigh-energy lines.Therefore,RCCWSdoesnotchallengeGDC2orGDC4.

2.TheRCCWScontainmentisolationvalvesarepartofthecontainmentsystems.Section6.2, ContainmentSystems,describescontainmentisolationvalvesandcompliancewithGDC2.

Table6.2-5documentsafailuremodesandeffectsanalysisofthecontainmentsystemsthat

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includesRCCWSpenetrationsintoandoutofthecontainment.Table6.2-7contains classificationsofsomeoftheRCCWScomponentsthatpenetratethecontainment.Consistent withGDC2,RCCWScomponentswhosefailurecouldadverselyimpactSeismicCategoryI componentsaredesignedtoSeismicCategoryIIstandards.Duetoitsproximitytothe containmentvessel,theRCCWSpipingfromtheNPMdisconnectflangetothemodulebaywall isdesignedtoSeismicCategoryIIstandards.TheRCCWScomponentsbeyondthepipegallery wallaredesignedtoSeismicCategoryIIIstandards.CompliancewithGDC2isnotchallenged (Section9.2.2.3andTable9.2.2-1).

3.Whilethecontrolroddrivemechanisms(CRDMs)aresafety-relatedduetotheirfunctionof safeshutdownofthereactor,theelectromagneticdrivecoilsandrodpositionindicationthatare cooledbyRCCWSdonotimpacttheabilitytosafelyshutdownthereactor.Whilecontinued coolingoftheCRDMsisnotrequiredforsafeshutdown,thereactorcomponentcoolingwater systemmaintainstheCRDMwindingtemperaturebelowthemaximumdesigntemperatureof 392degreesFahrenheit.Therefore,theRCCWSsystemdoesnotaffectCRDMcompliancewith GDC26.FurtherdetailabouttheCRDMsiscontainedinSection3.9MechanicalSystemsand Components.Table9.2.2-1:ClassificationofStructures,Systems,andComponents,contains thesafetyandseismicclassificationsforRCCWS,includinginterfaceswithCRDM.

4.TheRCCWSdesignmeetsGDC60andGDC64astheyrelatetothecontrolofradiological effluentsandmonitoringofreleases.Table12.3-31:RegulatoryGuide4.21DesignFeaturesfor ReactorComponentCoolingWaterSystem,andTable12.3-35:RegulatoryGuide4.21Design FeaturesforRadioactiveWasteDrainSystem,inSection12.3,RadiationProtectionDesign Features,containinformationabouthowtheRCCWSsystemcomplieswith10CFR20.1406 andGDCs60and64.BothTablesdiscussleakageminimizationanddetectionintheRCCWS anditsdrainsystemandthus,demonstratecompliancewithGDC60.

TheRCCWScoolscomponentsthatcontainfluidthathasthepotentialtocontaminatethe RCCWSwithradioactivity.Forthesepotentiallycontaminatedloads,radiationmonitorsare locatedintheRCCWSpipingdownstreamofthecooledcomponentstoalertthecontrolroomif thereisaradioactivefluidleakintotheRCCWS.Coolersandcondenserscontainmanual isolationvalvestoisolateleaks.Table11.5-1describesRCCWSmonitoringcapabilitiesto demonstratecompliancewithGDC64.

ImpactonUS460SDA:

TherearenoimpactstoUS460SDAasaresultofthisresponse.

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