Reactor Core Concept for an MIT Nuclear Power Station for the Moon andMars

摘要

President Bush declared his desire to pursue human exploration beyond Earth in arnspeech to NASA in January 2004. Mr. Bush challenged NASA to a rigorous schedule, replacingrnthe Space Shuttle by 2010 and returning to the Moon by 2020 to test technology for mannedrnmissions to Mars.rnTo meet the demands of human exploration on the surfaces of the Moon and Mars, a robust,rnreliable power source is required. The challenges presented by these two environments exclude thernuse of chemical, solar or radioisotope power sources in the long-term and lead inexorably to thernuse of fission reactor technology.rnThis investigation details the design of a core for a 100kWe fission reactor intended tornoperate without maintenance for at least 5 years on the Lunar or Martian surface. This systemrnwas designed around four primary considerations. It needed to be compact and lightweight tornreduce launch costs and maximize launch vehicle options. It had to have high reliability andrnredundancy to insure an uninterrupted power supply for people and equipment. The systemrnrequired a simple control scheme to allow for completely autonomous operation. Finally, it had tornexhibit excellent launch and landing safety characteristics not only to insure safety during launch,rnbut also to belay public concerns regarding the launch of nuclear reactors into space.rnThese constraints lead to the selection of a fast fission reactor using Uranium Nitride fuelrnpins in a tricusp arrangement with Lithium heat pipes. This configuration exhibits excellentrnthermal conductivity and allows the heat pipes to remove thermal energy from the core at 1800Krnwhile still maintaining large thermal margins to protect against damage during transients. Thernfuel is 33.1 w/o enriched 235U with a Tantalum (Ta) burnable poison. As the system also has arnconversion ratio higher than one, it is able to maintain uniform reactivity over life. Externalrncontrol drums provide control for the core with a Tantalum Di-Boride (TaB2) shutter materialrnplaced inside a Tri-Zirconium Di-Silicide (Zr3Si2) reflector. A Hafnium (Hf) vessel offersrnstructural support around the core, inside of the reflector and control drums, and absorbs thermalrnneutrons helping to reduce reactivity under certain launch accident scenarios.rnThis system is versatile, being able to operate on the Moon, on Mars, and in space. It isrnrobust having no single point failure modes, requiring no maintenance and it meets the challengernof providing power for long-term human exploration of extraterrestrial environments.