Martian Surface Reactor Group December 3 2004 Massachusetts Institute of Nuclear Engineering Technology Department Martian Surface Reactor Group Motivation for Mars We need to see and examine and touch for ourselves and create a new generation of innovators and pioneers Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 12 3 2004 Slide 2 Motivation for MSR NASA Concept Exploration and Refinement Study Surface Power Electric Power Level kWe Lunar Surface Power Options Fission Reactor Fission Reactor Solar Chemical Solar Radioisotope Solar Martian Surface Power Options Solar power becomes much less feasible Mars further from Sun 45 less power Day night cycle Dust storms Too short Lifetime for Martian missions Nuclear Power dominates curve for Martian missions Duration of use 10 15 2004 Slide 1 Bill Nadir Massachusetts Institute of bnadir mit edu Competition Sensitive Do not distribute outside of NASA Draper MIT team Nuclear Engineering Technology Department MSR Group 12 3 2004 Slide 3 Nuclear Physics Engineering 101 Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 12 3 2004 Slide 4 Nuclear Physics Engineering 101 Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 12 3 2004 Slide 5 Goals Litmus Test Works on Moon and Mars 100 kWe 5 EFPY Obeys Environmental Regulations Safe Extent To Which Test Small Mass and Size Controllable Launchable Accident Safe High Reliability and Limited Maintenance Scalability Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 12 3 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 12 3 2004 Slide 7 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 12 3 2004 Slide 8 Proposed Mission Architecture Habitat Massachusetts Institute of Nuclear Engineering Technology Department Reactor MSR Group 12 3 2004 Slide 9 CORE Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 12 3 2004 Slide 10 Core Design Concept Design criteria 100 kWe reactor on one rocket 5 EFPY Low mass Safely Launchable Maintenance Free and Reliable Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 12 3 2004 Slide 11 Core Design Choices Fast Spectrum High Temp Ceramic Fuel Uranium Nitride 33 1 w o enriched Lithium Heatpipe Coolant Tantalum Burnable Poison Hafnium Core Vessel External Control By Drums Zr3Si2 Reflector material TaB2 Control material Fuel Pin Elements in tricusp configuration Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 12 3 2004 Slide 12 Core Pin Geometry Fuel pins are the same size as the heat pipes and arranged in tricusp design Heatpipe Fuel Pin Tricusp Material Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 12 3 2004 Slide 13 Core Design Advantages UN fuel Ta poison Re Clad Structure high melting point heat transfer neutronics performance and limited corrosion Heat pipes no pumps excellent heat transfer reduce system mass Li working fluid operates at high temperatures necessary for power conversion unit 1800 K Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 12 3 2004 Slide 14 Core Reactivity Control Reflector controls neutron leakage Control drums add little mass to the system and offer high reliability due to few moving parts 88 cm Reflect or Fuel Pin 10 cm Reflector Reflector and Core Top Down View Control Drum 42 cm Fuel Core 10 cm Zr3Si2 Reflector Total Mass 2654kg Massachusetts Institute of Nuclear Engineering Technology Department Reflector Radial Reflector MSR Group 12 3 2004 Slide 15 Core Smear Composition Material 7 Li 15 N Nat Nb 181 Ta Nat Re 235 U 238 U Purpose Coolant Fuel Compound Heatpipe Poison Cladding Structure Fissile Fuel Fertile Fuel Massachusetts Institute of Nuclear Engineering Technology Department Volume Fraction 0 072759469 0 353381879 0 076032901 0 037550786 0 110216571 0 116593812 0 233464583 MSR Group 12 3 2004 Slide 16 Core Power Peaking Peaking Factor F r 1 4 1 2 F r 1 0 8 0 6 0 4 0 2 0 22 20 18 16 14 12 10 8 6 4 2 0 2 4 6 8 10 12 14 16 18 20 22 Core Radius cm RPPRDrums In 1 31 Massachusetts Institute of Nuclear Engineering Technology Department RPPFDrums Out 1 24 MSR Group 12 3 2004 Slide 17 Operation over Lifetime keff over Core Lifetime 1 20 BOL keff 0 975 1 027 1 05 EOL keff 0 989 1 044 Dkeff 1 10 0 052 0 055 keff Dkeff 1 15 1 00 0 95 0 90 0 85 0 80 0 1 2 3 4 5 Years at Full Power Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 12 3 2004 Slide 18 6 Launch Accident Analysis Worst Case Scenarios Oceanic splashdown assuming Non deformed core All heat pipes breached and flooded Dispersion of all 235U inventory in atmosphere Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 12 3 2004 Slide 19 Launch Accident Results Total dispersion of 235U inventory 104 kg will increase natural background radiation by 0 024 Inadvertent criticality will not occur in any conceivable splashdown scenario Reflectors Stowed Reflectors Detached Keff 0 97081 0 00092 Keff 0 95343 0 00109 Wet Sand Keff 0 97387 0 00095 Keff 0 96458 0 00099 Water Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 12 3 2004 Slide 20 Core Summary UN fuel Re clad structure Ta poison Hf vessel Zr 3Si2 reflector Low burn 5 EFPY at 1 MWth 100 kWe Autonomous control by rotating drums over entire lifetime Flat temperature profile at 1800K Subcritical for worst case accident scenario Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 12 3 2004 Slide 21 Future Work Investigate further the feasibility of plate fuel element design Optimize tricusp core configuration Examine long term effects of high radiation environment on chosen materials Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 12 3 2004 Slide 22 PCU Massachusetts Institute of Nuclear Engineering Technology Department MSR Group 12 3 2004 Slide 23 PCU Mission Statement Goals Remove thermal energy from the core Produce at least