Thermal Insulation Design of Portable Radioisotope Electrical Generators

Abstract

Radioisotope generators can provide power for several decades without the need of any further energy input, such as solar or chemical energy. A portable radioisotope generator can foresee many applications in future military and civilian uses that require minimum access and maintenance, such as to power sensors in a polar region, on a floating buoy, or undersea. In this work, we report the design, simulation, and measurement results of the thermal insulation of a miniaturized radioisotope system. We tested a prototype powered by an electrical heater with the same size as a plutonium fuel pellet. We tested the material compatibilities and showed the designs suitable for generators using thermoelectric and thermophotovoltaic converters respectively. In addition, we proposed a new insulation that uses a layered dielectric's omni-directional reflectivity as a futuristic insulation mechanism to shield radiation heat for micro to meso-scale thermal systems.