Reducing Pu(IV) to Pu(III) with hydroxylamine in nitric acid solutions

Los Alamos National Laboratory (LANL) has evaluated different techniques to concentrate and remove plutonium from solutions stored at the Rocky Flats Environmental Technology Site (RFETS). Pu(III) oxalate precipitation was chosen to treat nitric acid solutions because it is a simple and efficient technique for removing plutonium. Reducing Pu(IV) to Pu(III) is a key process step which affects the rest of the processing sequence. Because of differences in the literature1 over the kinetics of the reaction, additional data was obtained and compared with existing data to examine the kinetic relationship, and determine an appropriate relationship for future engineering evaluations. The results and conclusions of this work, along with new experimental data, are presented.