New actinides extractants for the nuclear fuels reprocessing

Other extractants of actinides than TBP will be surveyed and evaluation of their potentiality to replace TBP will be given. As wastes minimization appears one of the goal of the research and development, it is necessary to limit the amounts of wastes of nuclear fuels reprocessing. The nature of the organic solvents plays an important role. The complete extractant incinerability and regeneration process avoiding the use of saline solutions must be searched for. First we will consider the N,N-dialkylamides of carboxylic acids as alternative to TBP in PUREX type processes. The basic chemistry of actinide extraction by several N,N dialkylamides will be discussed as well as their hydrolytic or radiolytic behavior. Results of counter current separations will be presented and the up-to-date evaluation of N,N-dialkylamides as industrial extractant will be given. The second part will be devoted to the problem of extracting trivalent actinides from acidic aqueous solutions. We will compare the behavior of N,N'-tetraalkyl-malonamides and N,N' pentaalkyles propanediamides to the organophosphorus bidentate extractants described in the literature. Original data for the actinides and fission products chemistry of extraction will be presented. The practical interest of diamides will be discussed through the up to date knowledge of their radiolytic or hydrolytic behavior. Results of counter-current chemical separations will be reported and the amount of research and development still necessary to make diamides industrial useful extractant will be evaluated