Thermal Insulation Design of Portable Radioisotope Electrical Generators

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.