PREPARATION OF HEXAVALENT AMERICIUM IN NITRIC-ACID SOLUTION

Fundamental investigations on preparation of Am(VI) in nitric acid sol utions of various concentrations were carried out in order to develop a partitioning method for americium from high level liquid waste gener ated from the reprocessing of spent fuel. A mixture of ammonium peroxo disulfate and silver nitrate was used as oxidizing reagent. The yields of Am(VI) were determined as a function of the concentrations of nitr ic acid (0.01-2 M) and oxidizing reagent (0.1-2 M) and temperature (55 -85 degrees C). The yield of Am(VI) decreased with increasing concentr ation of nitric acid. In 1 M nitric acid solution, increasing the conc entration of ammonium peroxodisulfate resulted in increased of Am(VI) yield. When 1.5 M ammonium peroxodisulfate and 0.01 M silver nitrate w ere used, 90% of the americium in 1 M nitric acid solution was oxidize d to the hexavalent state at 85 degrees C.