Plutonium-238 recovery from irradiated neptunium targets using solvent extraction

Full text: Plutonium-238 is utilized in radioisotope thermoelectric generators, a method of providing electricity for space applications. Necessary separation steps for producing and recovering Pu-238 include initial purification of neptunium-237 from the protactinium-233 daughter to facilitate glove box target fabrication, as well as separation of Pu and Np from cladding and fission products, and separation of Pu from Np after target irradiation. The baseline process for completing these separations involve ion exchange methods using anion and/or cation exchange resins, which result in significant waste generation. An alternative approach is to use solvent extraction methods to perform these separations. The use of solvent extraction methods is anticipated to reduce waste volumes and improve separation efficiency. By utilizing centrifugal contactors with short phase contact times, solvent damage from Pu-238 alpha decay will be minimized. Results showing the separation efficiencies for Pa from Np as well as Pu from Np and fission products will be shown