Evaluation of anion exchange resins for pre-analysis separation of actinides

Anion exchange is the technique usually employed to separate plutonium and neptunium from actinides and other sample constituents prior to radiochemical determinations of the actinides. For plutonium-neptunium separations, neptunium(IV) is sorbed on an anion exchanger and the plutonium(III) allowed to pass with the effluent and wash streams from a 5M HNO/sub 3/-0.66M Al(NO/sub 3/)/sub 3/-0.2M Fe(SO/sub 3/NH/sub 2/)/sub 2/ feed solution. Plutonium is separated from plutonium-uranium solutions by sorbing plutonium(IV) on the resin from a 7M HNO/sub 3/ feed and permitting the uranium(VI) to follow the effluent and wash streams. In both cases, plutonium and neptunium are eluted from the resins with dilute nitric acid. For the actinide separations, pellicular, macroreticular, and microreticular (gel-type) anion exchange resins were compared. The pellicular and macroreticular (porous gel) resins showed faster elution and washing properties for the nonsorbable ions than the microreticular resins. However, the actinide breakthrough capacities of the pellicular and macroreticular resins were less than the microreticular resins but the breakthrough capacities for the macroreticular resins were dependent on actinide feed concentrations.