Plutonium processing coordination

The discovery of nuclear fission in 1938 proved the next driver in the development of coordination chemistry. Uranium-235 and plutonium-239 both undergo fission with slow neutrons, and can support neutron chain reactions, making them suitable for weaponization in the context of the Manhattan project. This rapidly drove the development of large-scale separation chemistry, as methods were developed to separate and purify these elements. While the first recovery processes employed precipitation methods (e.g., the bismuth phosphate cycle for plutonium isolation). 

As used in the tri-n-butyl phosphate (TBP), or PUREX, process to recover uranium (U) and plutonium (Pu), the solvent is typically a blend of about 30 vol% TBP and 70 vol% of an aliphatic diluent, say C-12 to C-15 branched paraffins. Spent nuclear fueP is dissolved in nitric acid and then contacted with this TBP solvent. Actinide elements, primarily uranium and plutonium, are coextracted into the organic layer by coordination and solvation with TBP. The extraction of uranium, for example, is thought to occur by the following reaction [14-21] ... 

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