Mid-year report: IPC liaison and chemistry of thermal reconstitution

A program of investigation into the chemistry of alkaline Hanford Site tank waste is being conducted. The investigations have two main subtasks: liaison with the Institute of Physical Chemistry of the Russian Academy of Sciences and further laboratory testing of the chemistry of thermal reconstitution of Hanford Site tank waste. Progress to date includes: (1) a technical dialogue has been established with the Institute scientists; (2) editing of a technical literature review on the chemistry of the transuranic elements and technetium in alkaline media written by researchers at the Institute is complete; (3) four tasks from the Institute have been selected for support by the US Department of Energy; (4) technical information has been supplied to the Institute describing the composition of Hanford Site tank waste; (5) tests, using genuine waste from tank 104-S (a REDOX Process sludge), comparing the performance of thermal reconstitution with enhanced sludge washing show markedly improved dissolution of aluminum achieved by the thermal treatment; (6) a reduction/coprecipitation method was tested and shown to remove plutonium, solubilized by thermal treatment, rapidly and efficiently from solution; (7) technical chemistry support was provided to calciner kinetics tests at the University of Idaho; (8) tests to determine the speciation of plutonium and neptunium solubilized by thermal treatment show dissolved Pu(V) and Np(V) hydroxide complexes are produced, a Np(V) peroxide complex also was identified; (9) recently published data on Pu(IV) carbonate complexation in moderately alkaline (pH 12 to 13) solution led to reexamination of previous investigations of plutonium complexation in highly alkaline (3 to 5 molar NaOH) solutions