Developing a Fundamental Basis for the Characterization, Separation, and Disposal of Plutonium and Other Actinides in High Level Radioactive Waste: The Effect of Temperature and Electrolyte Concentrations on Actinide Speciation

This research involves establishing a foundation for describing the speciation of actinides and lanthanides in the highly alkaline, concentrated electrolyte systems found in HLW. We are developing an experimentally derived thermodynamic description of Pu and actinide complexation in these systems. Initially, we are using chemical analogs for Pu; later we will conduct experiments using Pu itself. The primary matrix of interest is the Na- NO3-OH-H2O system. We are investigating complexation by OH-, acetate, oxalate, and multidentate organic ligands. In addition, we are complementing our thermodynamic measurements with spectroscopic studies to validate assumptions made concerning speciation and stoichiometry