Plutonium Partitioning Methods in Power Reactor Fuel Reprocessing

The bismuth phosphate process, developed and used during World War II for the isolation and purification of plutonium, did not provide for the recovery of uranium. Furthermore, this was inherently a batch process and thus not amenable to improvements in chemical processing which can be obtained with continuous operation. In the immediate postwar period, attention was devoted to solvent extraction methods which promised to overcome the shortcomings of the bismuth phosphate process. The Redox process, employing methyl isobutyl ketone (hexone) as the organic solvent and aluminum nitrate as the "salting agent" to promote the extraction of uranium and plutonium, was developed at the Argonne National Laboratory. Pilot-plant testing of the Redox process was done at the Oak Ridge National Laboratory (ORNL) in 1948 and 1949 and its large-scale use started at Hanford in 1952. In the Purex process, tributyl phosphate (TBP) in a hydrocarbon diluent is the organic solvent, while