Abstract :
NuclearreactorpowersystemscouldrevolutionizespaceexplorationandsupporthumanoutpostonthemoonandMars.Thispaperreviewsvariousenergyconversiontechnologiesforuseinspacereactorpowersystemsandprovidesestimatesofthesystemʹsnetefficiencyandspecificpower,andthespecificareaoftheradiator.Thesuitablecombinationsoftheenergyconversiontechnologiesandthenuclearreactors,classifiedbasedonthecoolanttypeandcoolingmethod,forbestsystemperformanceandhighestspecificpower,arealsodiscussed.Inaddition,anumberofpowersystemconceptswithbothstaticanddynamicenergyconversion,butwithnosinglepointfailuresinreactorcooling,energyconversionandheatrejection,andfornominalelectricalpowersupto110kWe,arepresented.Thefirsttwopowersystemsemployreactorscooledwithlithiumandsodiumheatpipes,SiGethermoelectric(TE)andalkali-metalthermal-to-electricconversion(AMTEC),andpotassiumheatpipesradiators.Thereactorsheatpipesoperateatafractionoftheprevailingcapillaryorsoniclimit,andinthecaseofamultipleheatpipesfailure,thoseintheadjacentmodulesremovetheadditionalheatload,thusmaintainingthereactoradequatelycooledandthepowersystemoperatingatareducedpower.ThethirdpowersystememploysSiGeTEconvertersandaliquidmetalcooledreactorwithadividedcoreintosixsectorsthatareneuroticallyandthermallycoupled,buthydraulicallydecoupled.Eachsectorhasaseparateenergyconversionloop,aheatrejectionloop,andarubidiumheatpipesradiatorpanel.Whenacoresectorexperiencesaloss-of-coolant,thefissionpowerofthereactorisreduced,andthatgeneratedinthesectorinquestionisremovedbythecirculatingcoolantintheadjacentsectors.Thefourthpowersystememploysagascooledreactorwithacoredividedintothreeidenticalsectors,andeachsectoriscoupledtoaseparateClosedBraytonCycle(CBC)loopwithHe–Xebinarymixture(40g/mol)workingfluid,asecondaryloopwithcirculatingliquidNak-78,andtwowaterheatpipesradiatorpanels.
