Dissolution of uranium, neptunium, plutonium and americium oxides in tri-n-butyl phosphate saturated with nitric acid

Uranium dioxide and its solid solutions with neptunium, plutonium and americium dioxides can be efficiently and quantitatively dissolved using tri-n-butyl phosphate (TBP) saturated with nitric acid. Individual NpO₂ and PuO₂ do not dissolve under these conditions. On the treatment of a mechanical mixture of UO₂ with PuO₂ and NpO₂ with TBP–HNO₃, a complex of uramiun completely dissolved, whereas Np and Pu remained in the residue.