DIAMIDES AS ACTINIDE EXTRACTANTS FOR VARIOUS WASTE TREATMENTS

Substituted propanediamides were studied at Fontenay-aux-Roses for the declassification of nuclear liquid wastes by extraction of all the actinides. Their synthesis has been improved. By optimization of the formula, it is possible to use aliphatic diluents without third-phase formation in contact with nitric acid at 20-degrees-C. Addition of oxalic acid allows separation of iron and zirconium from americium and plutonium. In selected conditions, it appears that americium extraction is faster than iron extraction, which could lead to practical applications. Recent studies have shown that diamides can be used to remove the actinides from waste solutions in chloride medium coming from defense facilities. The current knowledge and the projects for using diamides as actinide extractants will be reviewed.