The melting process of noncombustible solid wastes seems to be one of the most promising processes for volume reduction and immobilization. This melting process needs a high temperature of around 1500° C, but the behavior of radionuclides in such a process and at such a temperature has not been fully examined. We melted small contaminated samples to examine the behavior of radionuclides. Melted products were subjected to leaching tests.

Many assorted samples were melted, and we found that the vapour pressure of the radionuclide determined the distribution between melted products and dusts. The standard free energy of oxide formation and the quantity of stable nuclide of the radionuclide determined the distribution between metal and slag products. The leaching rate of melted products was sufficiently low.