Analysis and characterization of plutonium in pyrochemical salt residues

Quantitative measurement of hydrogen produced during salt-catalyzed hydroly sis of plutonium in pyrochemical salt residues show that the metal is prese nt in concentrations of 10+/-5 mass%. The analytical method is based on sto ichiometric reaction of metal with water to form plutonium monoxide monohyd ride (PuOH) and hydrogen. Results of a kinetic model developed to describe the observed time dependence of the hydrolysis rate shows that metal is pre sent predominately as particles with essentially spherical geometries and d iameters near 1 mm. The presence of smaller metallic particles cannot be ve rified or excluded. Plutonium concentrations measured for residues stored i n different configurations suggest that a sizable fraction of the metal has oxidized during storage. Application of the hydrolysis method in determini ng concentrations and dimensions of metallic plutonium in other nuclear was te forms is proposed. (C) 2000 Elsevier Science B.V. All rights reserved.