Towards effective management of radioactive waste
The ever growing needs on energy supply, particularly on cleaner energies, have brought new imposing demands on nuclear energy. Hence, this alternative form of energy unrelated to any carbon dioxide emissions provided on a massive scale is expected to account for large amounts of electricity produced. Although nuclear plants are currently taking increased measures in order to safeguard radioactive waste disposal, research is ongoing particularly for the longer-lived radioactive wastes. Thereby, the field of partitioning related to chemical separation techniques and transmutation associated in radio-nuclide conversion methods, is being continuously investigated. Within this area, PARTNEW project is working on new solvent extraction processes for minor actinides. Elements such as americium and curium are included in the highly active acidic raffinates (HARs) and concentrates (HACs) coming from the reprocessing of spent nuclear fuels. The work involves the development of key extractants, such as the diamides, nitrogen polydendate ligands, and acidic sulphur-bearing ligands that will be prepared through combinatorial synthesis procedures. Basic research and process studies showed the increased potential of the DIAMEX-SANEX processes in terms of their sensitivity related to the concentration of the HARs. In addition, preliminary test results were encouraging for future exploitation of the DIAMEX-HACs. Until now, it was very difficult to separate these minor actinides from fission products, in particular the trivalent lanthanides, contained within acidic effluents. The novel partitioning methods may lead to the successful removal of the minor actinides that may be further destroyed by transmutation techniques. Therefore, the successful PARTNEW project work will be part of the FP6 EUROPART Integrated project concerning partitioning of the actinides contained in the nuclear wastes issuing the reprocessing of nuclear spent fuels.
