Radionuclide transport behavior during melting and ingot making of ferrous waste

The development of technologies to recycle low-level radioactive waste from decommissioned nuclear facilities is a key issue from the view point of reducing waste and the recovering natural resources. Radionuclide transport behavior during melting is an important factor in the safety of radioactive metal (scrap) recycling. We obtained data on radionuclide transport from basic melting tests conducted in JAERI, and analyzed the data by using a statistical analysis method. As a result, it is found that the transport of Mn, Zn and Sr is mainly dominated by oxydation-reduction reaction between slag and molten metal and is explained on the basis of oxygen concentration in slag. On the other hand, the transport behavior of Cs is not explained by oxydation-reduction reaction. It is assumed that the partitioning of Cs to the off-gas is affected by its evaporation and restraint in silicic acid network structure. (author)