Lunar Surface Reactor Shielding Study
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)
- Sandia National Laboratories, Albuquerque, NM 87185 (United States)
A nuclear reactor system could provide power to support long term human exploration of the moon. Such a system would require shielding to protect astronauts from its emitted radiations. Shielding studies have been performed for a Gas Cooled Reactor system because it is considered to be the most suitable nuclear reactor system available for lunar exploration, based on its tolerance of oxidizing lunar regolith and its good conversion efficiency. The goals of the shielding studies were to determine a material shielding configuration that reduces the dose (rem) to the required level in order to protect astronauts, and to estimate the mass of regolith that would provide an equivalent protective effect if it were used as the shielding material. All calculations were performed using MCNPX, a Monte Carlo transport code. Lithium hydride must be kept between 600 K and 700 K to prevent excessive swelling from large amounts of gamma or neutron irradiation. The issue is that radiation damage causes separation of the lithium and the hydrogen, resulting in lithium metal and hydrogen gas. The proposed design uses a layer of B4C to reduce the combined neutron and gamma dose to below 0.5Grads before the LiH is introduced. Below 0.5Grads the swelling in LiH is small (less than about 1%) for all temperatures. This approach causes the shield to be heavier than if the B4C were replaced by LiH, but it makes the shield much more robust and reliable.
- OSTI ID:
- 20798012
- Journal Information:
- AIP Conference Proceedings, Vol. 813, Issue 1; Conference: 10. conference on thermophysics applications in microgravity; 23. symposium on space nuclear power and propulsion; 4. conference on human/robotic technology and the national vision for space exploration; 4. symposium on space colonization; 3. symposium on new frontiers and future concepts, Albuquerque, NM (United States), 12-16 Feb 2006; Other Information: DOI: 10.1063/1.2169252; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
DESIGN
EFFICIENCY
ENERGY CONVERSION
GAS COOLED REACTORS
HYDROGEN
IRRADIATION
LITHIUM
LITHIUM HYDRIDES
MONTE CARLO METHOD
MOON
NEUTRONS
RADIATION DOSES
RADIATION PROTECTION
REACTOR MATERIALS
SHIELDING
SHIELDING MATERIALS
SHIELDS
SURFACES
SWELLING
TOLERANCE