Solid-State Thermionic Nuclear Power For Megawatt ... · PDF fileSolid-State Thermionic Nuclear Power For Megawatt Propulsion, Planetary Surface And ... For Megawatt Propulsion, Planetary

ActiveProject(2013-2014)

Solid-StateThermionicNuclearPowerForMegawattPropulsion,PlanetarySurfaceAndCommercialPowerProjectCenterInnovationFund:JSCCIF(AlsoIncludesJSCIRAD)ProgramSpaceTechnologyMissionDirectorate(STMD)

AtStart:2 Current:2 AtEnd:4

1 2 3 4 5 6 7 8 9

AppliedResearch Development Demo&Test

NASA/JSCPropulsionandPowerDivision

ProjectTechnologyMaturity

ABSTRACT

Thermionic(TI)powerconversionisapromisingtechnologyfirstinvestigatedfor

powerconversioninthe1960’s,andofrenewedinterestduetomodernadvances

innanotechnology,MEMS,materialsandmanufacturing.Benefitsincludehigh

conversionefficiency(20%),staticoperationwithnomovingpartsandpotential

forhighreliability,greatlyreducedplantcomplexity,andthepotentialforreduced

developmentcosts.Thermionicemission,creditedtoEdisonin1880,formsthe

basisofvacuumtubesandmuchof20thcenturyelectronics.Heatcanbe

convertedintoelectricitywhenelectronsemittedfromahotsurfacearecollected

acrossasmallgap....Readmoreonthelastpage.

TechnologyArea: SpacePower&EnergyStorageTA03(Primary)In-SpacePropulsionTechnologiesTA02(Secondary)

ANTICIPATEDBENEFITS

ToNASAunfunded&plannedmissions:Thisprojecttargetsonethemostcriticalbarrierstohumandeepspaceexploration–the

meanstoefficientlypowerandrapidlypropelhumanmissionstoMarsandbeyond.The

projectwillexploretheimplementationofahighefficiency“Solid-State”Thermionic-based

nuclearfissionpowersystemstoserveElectricPropulsionsystemssuchasQ-thrusters,

VASIMR,Hall,orotherapproaches.ASolid-Stateapproachcenteredaroundadvanced

Thermionicpowerconverterswouldcombinethehighefficiencyoftraditionaldynamic

powerconversion(Rankine,Brayton,Stirling)withthesimplicityofastaticconverterwith

nomovingparts.Theresultingsystem...

Readmoreonthelastpage.

Printed4/4/2014 1

https://ntrs.nasa.gov/search.jsp?R=20140004416 2018-05-19T07:55:55+00:00Z

DETAILEDDESCRIPTION

Thermionic(TI)powerconversionisapromisingtechnologyfirstinvestigatedforpowerconversion

inthe1960’s,andofrenewedinterestduetomodernadvancesinnanotechnology,MEMS,

materialsandmanufacturing.Benefitsincludehighconversionefficiency(20%),staticoperation

withnomovingpartsandpotentialforhighreliability,greatlyreducedplantcomplexity,andthe

potentialforlowDesign,Development.TestandEvaluation(DDT&E)costs.Thermionicemission,

creditedtoEdisonin1880,formsthebasisofvacuumtubesandmuchof20thcenturyelectronics.

Heatcanbeconvertedintoelectricitywhenelectronsemittedfromahotsurfacearecollected

acrossasmallgap.Forexample,two“small”(6kWe)ThermionicSpaceReactorswereflownby

theUSSRin1987-88foroceanradarreconnaissance.HigherpoweredNuclear-Thermionic

powersystemsdrivingElectricPropulsion(Q-thruster,VASIMR,etc.)mayofferthebreakthrough

necessaryforhumanMarsmissionsof<1yrroundtrip.

...

Solid-StateThermionicNuclearPowerForMegawattPropulsion,PlanetarySurfaceAndCommercialPowerProject

MANAGEMENT

ProgramExecutive:JohnFalker

ProgramManager:RonaldGClaytonProjectManager:JeffreyGeorge

Printed4/4/2014 2

U.S.stateswithwork

Leadcenter:JohnsonSpaceCenter

Supportingcenters:GlennResearchCenter,MarshallSpaceFlightCenter,NASAHeadquarters


DETAILEDDESCRIPTION(CONT'D)

Thisprojecttargetsonethemostcriticalbarrierstohumandeepspaceexploration–themeanstoefficientlypower

andrapidlypropelhumanmissionstoMarsandbeyond.Theprojectwillexploretheimplementationofahigh

efficiency“Solid-State”Thermionic-basednuclearfissionpowersystemstoserveElectricPropulsionsystemssuch

asQ-thrusters,VASIMR,Hall,orotherapproaches.ASolid-StateapproachcenteredaroundadvancedThermionic

powerconverterswouldcombinethehighefficiencyoftraditionaldynamicpowerconversion(Rankine,Brayton,

Stirling)withthesimplicityofastaticconverterwithnomovingparts.TheresultingsystemcouldenableHuman

Marsmissionsof<1yearroundtripbyaffordingasystemofmegawattpower,lowspecificmass(<10kg/kWe),

greatlyreducedplantcomplexity,andassociatedsavingsindevelopmentcost.

Thisprojectprovidestheinitialfoundationandconfidenceforhighefficiencysolid-statepowerconverters,andearly

definitionofenabledhumanexplorationsystemsandmissions(ex.MegawattElectricPropulsion,Moon/Mars

SurfacePower).Subsequentconverterdevelopmentwillimprovereadinessandlifetime,leadingto“flightready”

articles.AnintermediateNASAinfusionstepwoulddemonstratekilowatt-classnuclearpowersystemsapplicableto

MoonorMarssurface.HumanvehiclesystemdevelopmentwouldthenintegratetheseconverterswithDOE

nuclearreactortechnology,NASAbalanceofplant(ex.radiators,PMAD),andelectricpropulsion(ex.Q-thrusters,

VASIMR,Hallthrusters)todevelopan“ultimate”NASAapplicationofaHumanMarsMegawatt-classNuclear

ElectricPropulsionvehicleandmission.Terrestrialapplicationswouldbeinformed/infusedresultinginhigh

efficiencypowersystemswithgreatlyreducedcomplexityandcost.

Printed4/4/2014 3


TECHNOLOGYDETAILS

AtStart:2 Current:2 AtEnd:4

1 2 3 4 5 6 7 8 9

AppliedResearch

Development Demo&Test

Solid-StateThermionic

NuclearPowerfor

MegawattPropulsion,

PlanetarySurfaceand

CommercialPower

TechnologyMaturity

ProjectDevelopmentPhases(3Years)

YearOne:Concepts,Missions,NanomaterialsEmission,LabConverterDemo.

Multi-MegawattNEPsystem&Marsmissionconcepts,modelsandanalysis.

Research&designofpracticalThermionicConverters.

Fabricatenanostructuredthermionicemittersofvarioussurfacesize&features.

Test&characterizethermionicemissionforvariousnanomaterials.

Examples:Tungsten,BaOcoated,alignedcarbonnanotubes,

nanocrystallinediamond

Demonstratethermionicpowerconversioninalaboratoryconfiguration.

Assess“modern”potentialtoincreaseefficiency,reduceoperationalemission

temperature,increasepowerdensity.

ExploreapplicabilitytosmallerpowersystemsfordeepspaceorMoon/Mars

surface,aswellaspotentialforsimpler,morecosteffectiveterrestrialnuclear

powerplants.

YearTwo:BreadboardConverterDDT&E.

YearThree:BrassboardConverterDDT&E

Thistechnologyiscategorizedasahardwaresystemformannedspaceflight

TechnologyArea

TA03SpacePower&Energy...

PerformanceMetrics

Metric Unit Quantity

PowerConversionEfficiency(atMaturity) % 20

Printed4/4/2014 4


TECHNOLOGYDETAILS

TECHNOLOGYDESCRIPTION(CONT'D)Storage(Primary)

TA02In-SpacePropulsionTechnologies(Secondary)

CAPABILITIESPROVIDEDThermionicconvertershaveaveryhighpotentialforDualUse.Commercialpowerplants,nuclearorotherwise,

wouldbenefitfromhighefficiencypowerconversionwithreducedplantcomplexity,maintenanceandcapitalcosts.

AnuclearplantbaseduponThermionicconversionmaybewellsuitedtomeetingDepartmentofEnergy(DOE)

goalsforitsnext-generationSmallModularReactorprogram.Atsmallerscales,successfulloweringoftheelectron

emissionthresholdwouldalsoallowThermionicconverterstoperformpowerscavengingorbottomingfrom

otherwise“wasteheat”.ThermionicswoulddoubletheefficiencyandrecoveryofThermoelectric“tailpipe”

convertersbeingdevelopedtoharnessautomotiveexhaustenergy,replacingelectricalalternatorsandeliminating

theirparasiticdragontheengine.

POTENTIALAPPLICATIONS1.SpaceNuclearPowerSystems

2.SpaceSolarPowerSystems

3.TerrestrialCommercialNuclearPowerPlants

4.TerrestrialCommercialFossilFuelPowerPlants

5.TerrestrialSolarPowerPlants

6.AutomobileWasteHeat"Scavenging"

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IMAGEGALLERY

NASA/JSCPropulsionandPowerDivision

Printed4/4/2014 6


ABSTRACT(CONTINUEDFROMPAGE1)

Forexample,two“small”(6kWe)ThermionicSpaceReactorswereflownbytheUSSRin1987-88foroceanradar

reconnaissance.HigherpoweredNuclear-ThermionicpowersystemsdrivingElectricPropulsion(Q-thruster,

VASIMR,etc.)mayofferthebreakthroughnecessaryforhumanMarsmissionsof<1yrroundtrip.Power

generationonEarthcouldbenefitfromsimpler,moeeconomicalnuclearplants,and"topping"ofmorefueland

emissionefficientfossil-fuelplants.

Printed4/4/2014 7


ANTICIPATEDBENEFITS

ToNASAunfunded&plannedmissions:(CONT'D)couldenableHumanMarsmissionsof<1yearroundtripbyaffordingasystemofmegawattpower,lowspecific

mass(<10kg/kWe),greatlyreducedplantcomplexity,andassociatedsavingsindevelopmentcost.

AdvancedNuclear-ThermionicpowersystemsdrivingElectricPropulsion(Q-thruster,VASIMR,Hall,Ion,MPD,etc.)

mayofferthebreakthroughnecessaryforhumanMarsmissionsof<1yearroundtrip,resultinginsignificant

improvementtocrewhealthandsafety,largereductionsinconsumablesmass,massofsparesandredundancy,

andreduced"window"forcatastrophichardwarefailureorsolarflareevents.

Toothergovernmentagencies:TheDepartmentofEnergy(DOE)SmallModularReactor(SMR)Programmaybenefitfromthisworkintheareaof

efficientandeconomicalcommercialnuclearpowerplantswithfewerparts,fluidloops,andwasteproducts.

Tothenation:Terrestrialapplicationswouldbeinformedandinfusedresultinginhighefficiencypowersystemswithgreatly

reducedcomplexityandcost.Benefitsincludehighconversionefficiency(20%),staticoperationwithnomoving

partsandpotentialforhighreliability,greatlyreducedplantcomplexity,andpotentialforlowerDesign,

Development,TestandEvaluation(DDT&E)costs.Thiscouldleadtomoreefficientandeconomicalnuclearpower

plants,oralternativelyserveasa"topping"cycleinfossilfuelplantstoreducefuelconsumption,emissionsand

cost.Solarpowerplantsmaybecomeamorecompetitiveoption.Automobilesandbusesmayconsumelessfuel

andproducelasswastegasbyscavengingwasteheatfromengineblocksandexhaust.

Printed4/4/2014 8

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Solid-State Thermionic Nuclear Power For Megawatt ... · PDF fileSolid-State Thermionic Nuclear Power For Megawatt Propulsion, Planetary Surface And ... For Megawatt Propulsion, Planetary