1、,22.033 Final Design Presentation,Vasek Dostal Knut Gezelius Jack Horng John Koser Joe Palaia Eugene Shwageraus And Pete Yarsky With the Help of Kalina Galabova Nilchiani Roshanak Dr. Kadak,June 16th, 2003,22.033, Mission to Mars Design Course,Outline,Mission plan Space power system Surface power sy
2、stem Conclusions Future Work,June 16th, 2003,22.033, Mission to Mars Design Course,Mission Design Goals,Reduce costs Minimize initial launch masses. Make use of re-usable, scalable and evolvable systems. Increase science yield Increase surface stay times. Provide power rich environments. Leverage ad
3、vantages of nuclear energy to achieve these goals.,June 16th, 2003,22.033, Mission to Mars Design Course,Mission Plan Summary,Nuclear Powered Telecommunication Satellite in Mars orbit Demo space reactor & Electric Propulsion system Sample Return Demo surface reactor & ISRU plant Manned Exploration 2
4、 distinct transfer types Cargo Missions Crew Transfer Missions,June 16th, 2003,22.033, Mission to Mars Design Course,Cargo Missions,Large cargo mass to transfer. Efficient transfer desirable to reduce propellant mass. Transit time not critical (1+ year ok). Reusable Mars Transfer System (MTS) Ideal
5、application for Electric Propulsion technology. High Isp (high efficiency) Low thrust (long transit is tolerable),June 16th, 2003,22.033, Mission to Mars Design Course,Cargo Missions,June 16th, 2003,22.033, Mission to Mars Design Course,Electric Propulsion Options,Cargo missionsArray of advanced Ion
6、 / Hall thrusters,June 16th, 2003,22.033, Mission to Mars Design Course,Crew Transfer Missions,Fast transit required Reduces crew exposure to zero-gravity & radiation. Increases surface stay time. Requires high thrust to achievePropulsion Options VASIMR (only viable EP technology) NTR (Nuclear Therm
7、al Rocket) Chemical Rocket,June 16th, 2003,22.033, Mission to Mars Design Course,Crew Transfer Missions,3 Reactor Systems3 VASIMR EnginesHydrogen FuelTransfer Habitat,June 16th, 2003,22.033, Mission to Mars Design Course,Electric Propulsion (Manned Mission),Variable Specific Impulse Magnetoplasma Ro
8、cket VASIMR,10 MW of power,June 16th, 2003,22.033, Mission to Mars Design Course,Space Power System,June 16th, 2003,22.033, Mission to Mars Design Course,Nuclear Space Power System,Ultra-compact high power density reactor Fast Spectrum Pu Fuel Molten salt or Li coolant High temperature, low pressure
9、 coolant Good heat transport medium Thermo Photo Voltaic (TPV) cells High efficiency power conversion (up to 40%) No moving parts,June 16th, 2003,22.033, Mission to Mars Design Course,Space Power System Goals,Design for multiple round trips three 180 day round trips at full power Low mass 3 kg/kWe S
10、calable 200 kWe - Precursor 4000 kWe - Manned Simple and reliable No moving parts,June 16th, 2003,22.033, Mission to Mars Design Course,Reusable System Strategy,Cargo missions (Mars Transfer System) 1 new tank of propellant per transfer 1 new reactor core after 3 transfersCrew transfer (VASIMR Syste
11、m) 1 new tank of propellant per transfer 3 new reactor cores after 3 transfers,June 16th, 2003,22.033, Mission to Mars Design Course,Pu as a Fuel,Most reactive fuel in fast spectrum Small core size and mass Critical mass is independent of isotopic composition Proliferation resistant Reactor Grade Pu
12、 can be used Compact core High leakage, allows ex-core control Small shield Widely available Reduced cost (238Pu for Cassini mission was imported),June 16th, 2003,22.033, Mission to Mars Design Course,Molten Salt Fast Reactor: Reference Core Design,Power 11 MWth Dimensions 202020cm Total mass 185 kg
13、 - (50 kg Pu) Reflector thickness 6 cm (Zr3Si2) Coolant - molten salt (NaF-ZrF4) - High Boiling Temp Fuel - Reactor Grade Pu carbide,honeycomb plates keff BOL = 1.1 Core lifetime 540 FPD,Honeycomb Fuel,MSFR Core Layout,June 16th, 2003,22.033, Mission to Mars Design Course,MSFR Technology Challenges,
14、Fuel performance (El-Genk et al. 1984)Coated particle dispersed alternative fuel form Fuel Cladding Coolant compatibility Li as alternative to corrosive Molten Salt High temperature structural materials,June 16th, 2003,22.033, Mission to Mars Design Course,MSFR Technology Challenges (cont.),Pu fuel
15、environmental concernsWater submersion accident Launch in robust capsule,June 16th, 2003,22.033, Mission to Mars Design Course,Space Power Conversion Cycle Reference Concept,Coolant transfers the heat from the core to the internal radiator All power is radiated towards TPV collector TEM self powered
16、 pumps circulate the molten salt coolant TPV collectors generate DC from thermal radiation Residual heat is radiated into outer space,reactor,shield,pump,TPV array,Internal Radiator,External radiator,June 16th, 2003,22.033, Mission to Mars Design Course,TPV Technology Challenges,Relatively low opera
17、ting temperature needed for high efficiency,June 16th, 2003,22.033, Mission to Mars Design Course,TPV Technology Challenges: Potential Solutions,Deployable radiator Liquid Droplet Radiator,June 16th, 2003,22.033, Mission to Mars Design Course,MSFR Scalability,June 16th, 2003,22.033, Mission to Mars
18、Design Course,Shielding MSFR,Neutron Attenuation: LiH Gamma Attenuation: W,June 16th, 2003,22.033, Mission to Mars Design Course,Shield Design Issues,Structural Design Radiation induced LiH expansion Thermal Design 6Li (n,) reaction 7Li enrichment Proximity to the reactor core Operating in temperatu
19、re range 600-650 K,June 16th, 2003,22.033, Mission to Mars Design Course,Surface Power System,June 16th, 2003,22.033, Mission to Mars Design Course,Surface Power System Goals,Sufficient power for all surface applications (i.e. ISRU, habitat etc.) Satisfy NASA DRM.200 kWeDevelop long lasting Mars sur
20、face infrastructure Lifetime of 25 EFPY,June 16th, 2003,22.033, Mission to Mars Design Course,Surface Nuclear Power System,Cooled by Martian atmosphere (CO2) Insensitive to leaks or ingress Shielded by Martian soil and rocks Low mass Hexagonal block type core Slow thermal transient (large thermal in
21、ertia) Epithermal spectrum Slow reactivity transient Low reactivity swing,June 16th, 2003,22.033, Mission to Mars Design Course,CECR Core Design,Power 1 MWth Dimensions L=160 cm, D=40 cm 37 hexagonal blocks Total mass 3800 kg Reflector thickness 30 cm (BeO) Coolant Martian atmosphere (CO2) Fuel 20%
22、enriched UO2 dispersed in BeO keff BOL = 1.14 Core lifetime 25 EFPY,CECR Core Layout,Fuel Pins,Control Drums,June 16th, 2003,22.033, Mission to Mars Design Course,CECR Thermal Hydraulics (fix it),System pressure 480 kPa Core inlet temperature 486 C Core outlet temperature 600 C Core mass flow rate 7
23、.47 kg/s Channel diameter 30 mm Block flat-to-flat 63 mm Film temperature difference 2.5 C Pressure drop 25 kPa,June 16th, 2003,22.033, Mission to Mars Design Course,CECR,Two Martian atmosphere Brayton cycle options investigated: Open cycle - intake from and discharge to the atmosphere Closed cycle
24、- intake from the atmosphere through a Martian atmosphere storage tank Pressurized CO2 from atmosphere cools the core Open cycle - 100 kPa Closed cycle - 500 kPABoth options are capable of achieving 20% efficiency,CO2 Cooled Epithermal Conversion Reactor,June 16th, 2003,22.033, Mission to Mars Desig
25、n Course,CECR,CO2 Cooled Epithermal Conversion Reactor,OPEN CYCLE,CLOSED CYCLE,CO2 storage tank,June 16th, 2003,22.033, Mission to Mars Design Course,Acceptable efficiency (20% achievable) Open cycle Simple Requires pressure ratio of 18 Closed cycle heat rejection is the weakest point of the design
26、massive pre-cooler or a fan is required precooler increases the overall mass of the system fan reduces the efficiency to 20% The design requires further optimization,CECR,Power Conversion Cycle,June 16th, 2003,22.033, Mission to Mars Design Course,Surface Reactor Shield,Martian soil,Core,Place for s
27、hutters,June 16th, 2003,22.033, Mission to Mars Design Course,Conclusions,Mission plan Technology demonstration Reliability assurance before people are committed Long term, reusability strategy Reduces recurring costs to future missions,June 16th, 2003,22.033, Mission to Mars Design Course,Conclusio
28、ns,MSFR Space Reactor Features: Very high temperature, low pressure Thermo Photo Voltaic energy conversion Potential for High efficiency Ultra compact core Fast spectrum, RG Pu fueled Potentially reduced shield mass,June 16th, 2003,22.033, Mission to Mars Design Course,Conclusions,CECR Surface React
29、or Innovations Epithermal spectrum Slow kinetics (maintains large and eff) Enhanced conversion Compromise between advantages of fast and thermal systems CO2 coolant Local resource Resistant to leaks or ingress Martian soil shield,June 16th, 2003,22.033, Mission to Mars Design Course,Future Work,Furt
30、her Development of conceptual designs Molten Salt Fast Reactor Space System Fuel performance and materials compatibility issues with different coolants TPV & Radiator Technology Criticality with water submersion CO2 Cooled Epithermal Converter Further Open Cycle & Closed Cycle Investigation Developm
31、ent of low pressure and high pressure ratio turbomachinery Surface Reactor Heat Rejection Reactor startup & remote control strategy Mission & Systems Integration,June 16th, 2003,22.033, Mission to Mars Design Course,This surface reactor concept has been adapted for use with the Mars Homestead Project. For More Information, see: www.MarsHome.org,
