Nuclear Reactors for The Moon and Mars Tyler Ellis Michael Short Martian Surface Reactor Group November 14 2004 Massachusetts Institute of Nuclear Engineering Technology Department Martian Surface Reactor Group MSR Motivation Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 11 14 2004 Slide 2 Nuclear Physics Engineering 101 Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 11 14 2004 Slide 3 Nuclear Physics Engineering 101 Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 11 14 2004 Slide 4 Proposed Mission Architecture Habitat Massachusetts Institute of Nuclear Engineering Technology Department Reactor MSR Group 11 14 2004 Slide 5 MSR Mission Nuclear Power for the Martian Surface Test on Lunar Surface Design characteristics of MSR Safe and Reliable Light and Compact Launchable and Accident Resistant Environmentally Friendly Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 11 14 2004 Slide 6 MSR Components Core Nuclear Components Heat Power Conversion Unit Electricity Heat Exchange Radiator Waste Heat Rejection Shielding Radiation Protection Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 11 14 2004 Slide 7 CORE Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 11 14 2004 Slide 8 Core Design Concept Develop a 100 kWe reactor with a 5 full power year lifetime Evaluation of options were based on design criteria Low mass Launchability Safety High Reliability Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 11 14 2004 Slide 9 Core Design Choices Fast Spectrum Ceramic Fuel Uranium Nitride 35 w o enriched Tantalum Burnable Poison Liquid Lithium Heatpipe Coolant Fuel Pin Elements in tricusp configuration External control using drums Zr3Si2 Reflector material TaB2 Control material Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 11 14 2004 Slide 10 Core Design Specifications UN fuel and Ta poison were chosen for heat transfer neutronics performance and limited corrosion Heatpipes eliminate the need for pumps have excellent heat transfer and reduce system mass Li working fluid operates at high temperatures necessary for power conversion unit 1800K Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 11 14 2004 Slide 11 Core Design Specifications 2 Fuel pins are the same size as heatpipes and arranged in tricusp design Heatpipe Fuel Pin Tricusp Material Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 11 14 2004 Slide 12 Core Design Specifications 3 Reflector controls neutron leakage Control drums add little mass to the system and offer high reliability due to few moving parts 99cm Reflector and Core Top Down View Reflector Reflector Control Drum 37 cm Core 10cm Fuel Zr3Si2 Reflector Total Mass 1892kg Massachusetts Institute of Nuclear Engineering Technology Department Fuel Pin Radial Reflector MSR Group 11 14 2004 Slide 13 Core Future Work Perform U235 enrichment versus system mass analysis Investigate further the feasibility of plate fuel element design Develop comprehensive safety analysis for launch accidents Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 11 14 2004 Slide 14 PCU Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 11 14 2004 Slide 15 PCU Design Concept Goals Remove thermal energy from the core Produce at least 100kWe Deliver remaining thermal energy to the radiator Components Heat Removal from Core Power Conversion System Power Transmission System Heat Exchanger Interface with Radiator Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 11 14 2004 Slide 16 PCU Design Choices Heat Transfer from Core Heat Pipes Power Conversion System Cesium Thermionics Power Transmission DC to AC conversion OOOO gauge Cu wire transmission Heat Exchanger to Radiator Annular Heat Pipes Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 11 14 2004 Slide 17 PCU Design Specifications Heat Pipes from Core 1 meter long 1 cm diameter 100 heat pipes Molybdenum Pipes Lithium Fluid Boiling point STP 1615K Pressurized to boil 1800K Massachusetts Institute of Nuclear Engineering Technology Department CORE MSR Group 11 14 2004 Slide 18 PCU Design Specifications 2 Thermionic Power Conversion Unit Mass 250 kg Efficiency 10 1MWt 100kWe Power density 10W cm2 Surface area per heat pipe 100 cm2 Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 11 14 2004 Slide 19 PCU Design Specifications 3 Power Transmission D to A converter 20 x 5000VA units 300kg total Small Transmission Lines AC transmission OOOO gauge Cu wire 1kg m Massachusetts Institute of Nuclear Engineering Technology Department Reactor MSR Group 11 14 2004 Slide 20 PCU Decision Specifications 4 Heat Pipe Heat Exchanger Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 11 14 2004 Slide 21 PCU Future Work Improving Thermionic Efficiency Material behavior in high radiation environment Heat pipe failure analysis Scalability to 200kWe Using ISRU as thermal heat sink Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 11 14 2004 Slide 22 Radiator Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 11 14 2004 Slide 23 Radiator Design Concept Need a radiator to dissipate excess heat from a nuclear power plant located on the surface of the Moon or Mars Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 11 14 2004 Slide 24 Radiator Design Choices Evolved from previous designs for space fission systems SNAP 2 10A SAFE 400 SP 100 Transfers heat from PCU to heat pipes Radiates thermal energy into space via large panels Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 11 14 2004 Slide 25 Radiator Design Choices 2 Heat pipes send heat to large radiator panels through vaporization of fluid Heat conducted to panels at the condensing end of the heat pipes High emissivity panels use radiation to reject heat to space Q Radiated Power AT 4 t Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 11 14 2004 Slide 26 Radiator Design Specifications Nb Zr heat pipes with carbon radiator panels Panels folded vertically next to reactor during transit For operation panels lay