Separations science for radioactive materials: some perspectives

Separation of actinides, fission products and other radioisotopes at various concentration levels continues to demand the development of innovative procedures. This includes development of new separation systems, based on solvent extraction, ion exchange, membrane separation, etc. The issues to be addressed by development are based on the targeted application. The challenges for macro level extraction include the phenomenon of third phase formation, in many extraction systems. Choice of the extractant should also be based on overall evaluation taking into account related aspects such as wastes generated by the process, impact of the extractant and diluent used on environment, ease of synthesis, radiation and chemical stability, recyclability, etc. For applications related to analysis and for other separations at small scale, including tracer scale separations, many such restrictions may not apply, and a host of new procedures including ion imprinted polymers, chelating ion exchangers etc. can be envisaged. In more recent times, the emphasis on 'green chemistry' has made it attractive to develop environment friendly extraction systems. The impetus on room temperature ionic liquids has further diversified the design of extraction systems. This presentation deals with the challenges related to the design of the separations systems and particularly the solvent extraction systems. (author)