Gravity Scaling of a Power Reactor Water Shield
- NASA Marshall Space Flight Center, Huntsville, AL 35812 (United States)
Water based reactor shielding is being considered as an affordable option for potential use on initial lunar surface reactor power systems. Heat dissipation in the shield from nuclear sources must be rejected by an auxillary thermal hydraulic cooling system. The mechanism for transferring heat through the shield is natural convection between the core surface and an array of thermosyphon radiator elements. Natural convection in a 100 kWt lunar surface reactor shield design has been previously evaluated at lower power levels (Pearson, 2006). The current baseline assumes that 5.5 kW are dissipated in the water shield, the preponderance on the core surface, but with some volumetric heating in the naturally circulating water as well. This power is rejected by a radiator located above the shield with a surface temperature of 370 K. A similarity analysis on a water-based reactor shield is presented examining the effect of gravity on free convection between a radiation shield inner vessel and a radiation shield outer vessel boundaries. Two approaches established similarity: 1) direct scaling of Rayleigh number equates gravity-surface heat flux products, 2) temperature difference between the wall and thermal boundary layer held constant on Earth and the Moon. Nussult number for natural convection (laminar and turbulent) is assumed of form Nu = CRa{sup n}. These combined results estimate similarity conditions under Earth and Lunar gravities. The influence of reduced gravity on the performance of thermosyphon heat pipes is also examined.
- OSTI ID:
- 21043566
- Journal Information:
- AIP Conference Proceedings, Vol. 969, Issue 1; Conference: Space Technology and Applications International Forum-STAIF 2008: 12. conference on thermophysics applications in microgravity; 1. symposium on space resource utilization; 25. symposium on space nuclear power and propulsion; 6. conference on human/robotic technology and the vision for space exploration; 6. symposium on space colonization; 5. symposium on new frontiers and future concept, Albuquerque, NM (United States), 10-14 Feb 2008; Other Information: DOI: 10.1063/1.2844983; (c) 2008 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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