Liquid Metal Loop and Heat Pipe Radiator for Space Reactor Power Systems

Abstract

This paper presents four radiator configurations that could be stowed in the launch bay of the DELTA-IV Heavy vehicle and have effective areas of 69.1 to 350 m 2 . The radiator for a space reactor power system with a lithium-cooled sectored compact reactor and thermoelectric converters has an effective area of 203 m 2 and lowest specific mass. The sectored compact reactor and thermoelectric converters system generates ∼114 kWe for 7-10 years. The radiator consists of six panels, each having a forward, fixed segment and two rear, deployable segments, and rejects heat into space using rubidium heat pipes with carbon-carbon armor and fins. The D-shaped heat pipes operate below 50 % of the prevailing sonic or capillary limit. The radiator operates at a constant pressure drop of 12 kPa and inlet and exit temperatures of 780 and 755 K. Investigated are the effects on the radiator's specific mass and lithium inventory of 1) tapering and changing width of coolant channels, 2) thermal-hydraulically coupling the panel segments in parallel, and 3) using perforated dividers between inlet- and exit-channels. The radiator with perforated dividers has a wet specific mass of 6.82 kg/m 2 , a liquid-lithium inventory of 179.3 liters, and a stowed height of 8 m.