DEVELOPMENT OF NEW MATRICES FOR CONDITIONING SEPARATED RADIONUCLIDES

摘要

Legislation passed in December 1991 has spurred research in France on enhanced separation of long-lived radionuclides for transmutation or conditioning. The investigation of new conditioning matrices addresses the containment of long-lived fission products such as iodine or cesium in addition to the actinides. Several matrices are currently being developed, including zirconolite ceramics and glass ceramics, apatite ceramics for conditioning actinides, hollandite glass ceramics or apatite ceramics for conditioning cesium, apatite ceramics for conditioning iodine. The material selection is based on three major criteria: the radionuclide loading capacity of the mineral structure, the long-term containment performance (self-irradiation resistance and chemical durability from the standpoint of interim storage or ultimate disposal), and the fabrication process (melting or sintering) at laboratory and industrial scale with radioactive materials. Development work on these matrices is currently focused on the formulation of suitable compositions, fabrication at laboratory scale using high-temperature cold-crucible melting and natural or hot-press sintering processes, characterization and initiation of leach-testing behavior assessments.