Introduction, Motivation, and Outcomes from the Session

Deep space exploration missions require reliable power. Plutonium-238 is the radioisotope of choice for the US National Aeronautics and Space Administration (NASA) to provide power to deep space probes, such as rovers, in the form of radioisotope thermoelectric generators. Oak Ridge National Laboratory (ORNL) is establishing constant rate production of plutonium-238 heat source material to support future NASA deep space exploration missions. The production life cycle of plutonium-238 involves a number of radiochemical and nuclear material processing steps. These steps include purification of neptunium material, chemically transforming dissolved neptunium nitrate into oxide powder, pressing mixed neptunium oxide with aluminum powders into cermet pellets, fabricating metal-clad reactor target bodies containing the neptunium cermet pellets, irradiating the neptunium targets in a reactor with a high flux of neutrons, and radiochemically processing irradiated targets in a hot cell facility to result in a plutonium-238 oxide product stream and neptunium nitrate stream for recycling into new targets. The processing of waste produced throughout the entire production life cycle into disposal forms is also crucial. This presentation will provide an overview of radiochemical processing at ORNL for plutonium-238 production and discuss new research directions that are being explored to improve efficiency.