Innovative technologies for immobilizing the sodium primary coolant of fast neutron reactors and processing liquid radioactive waste generated during reactor operation

The paper considers the issues of processing spent alkaline liquid metal coolant of BN reactors. Methods used in the BR-10 research reactor for processing coolant and its residues are described in detail. The main parameters of solidified products including mechanical strength and cesium-137 leaching rate are provided. The obtained data are compared with the indicators of cement compounds immobilizing an alkaline solution obtained by dissolving radioactive sodium in 10% alkali. The efficiency of purifying high-salt concentrates of liquid radioactive waste generated during reactor decommissioning is provided for three options of modified clinoptilolite. An approach to processing liquid radioactive waste concentrates is briefly described. The current state of the BN-350 reactor is considered indicating the need for processing accumulated radioactive waste for further decommissioning.