An Alternative Solvent Extraction Flowsheet for Separating 237Np from 238Pu for Space Power Applications

ABSTRACT The production of 238Pu from 237Np, to the specifications required for space flight, requires the separation of plutonium from neptunium and a range of fission products. The valuable neptunium is then recycled into targets for further irradiation. At Oak Ridge National Laboratory (ORNL), a solvent extraction process has been developed to separate neptunium and plutonium that uses sodium nitrite to control the neptunium oxidation. This results in a neptunium product contaminated with sodium, which needs to be removed prior to recycling. We have developed a separation process that results in a sodium-free neptunium product with very low levels of plutonium contamination, there by reducing the number of purification steps and thus simplifying the process.