Release of Radionuclides into the Gas Phase from a LiCl–Li2O Salt Melt in the Step of the “Metallization” of Oxidized Spent Nuclear Fuel

The release of radionuclides into the gas phase from a LiCl–Li₂O salt melt in the “metallization” operations in the course of pyrochemical reprocessing of spent nuclear fuel was studied. The experiments were performed at three temperatures characterizing the normal operation and violation of the normal conditions: 650, 750, and 850°С. Alkali and alkaline-earth elements showed the highest rate of the release into the gas phase, of the order of 10²–10³ g/(m² h), whereas the target components (uranium, plutonium, and minor actinides) quantitatively remained in the form of insoluble oxides in the salt melt. The major fraction of the radionuclides released into the gas phase was adsorbed on the walls of the pumping system. In the case of violation of the normal operation conditions, cesium and strontium make the major contribution to the gas phase activity.