New solutions to the problem of handling long-lived radionuclides

When spent nuclear fuel is recycled, particularly dangerous long-lived radionuclides are contained in the gaseous emissions. Until recently the problem of handling long-lived radionuclides was reduced to obtaining solidified waste material and its long-term storage or burial in geological formations. Promising research work is directed toward improving these methods and creating methods which, in principle, are novel. Specific developments have proceeded along the following lines: fractionation of long-lived radionuclides; improvements of the solidification techniques; nuclear transmutation of long-lived radionuclides; and removal of radioactive waste into the cosmic space. The authors define the fractionation of radioactive waste material (1) as the separation of a radioactive material from salts present in high-activity waste material and (2) as the separation of radionuclides with their isolation in chemically pure form or in groups in dependence upon the planned overall scheme of waste material handling. Technical and economical investigations show that only the first problem should be solved. Separation of the salts ensurse a sharp decrease in the mass of the solidified high-activity waste materials and a reduction of the expenses for preliminary storage to reduce heat liberation and for subsequent burial