SYNTHESIS OF GEOPOLYMER WASTE FORM TO SOLIDIFY RADIOACTIVE WASTES FROM DECONTAMINATION OF PRIMARY SYSTEM IN NUCLEAR POWER PLANT

Old nuclear power plant (NPP) is scheduled to stop operation followed by decommissioning, decontamination, and disposing of radioactive wastes. The solidification method using waste form should be developed for radioactive wastes generated from decontamination process of nuclear facilities and NPP in the world. Here, new waste form, geopolymer was developed using industrial byproducts (red mud and fly ash) and characterized to be compatible with the disposal environment for the secondary radioactive waste sludge containing radioactive Co and Cs generated from chemical decontamination process of primary system in NPP. Because of high sulfate content used in hydrazine base reductive metal ion decontamination (HyBRID) process, general cement waste form was not valid to form stable waste form. Geopolymer was successfully synthesized using red mud and fly ash, and showed stable conditions to meet the acceptance criteria in the repository. The results of this study will be used to solidify radionuclides present in secondary waste stream generated from chemical decontamination process of the decommissioned NPPs.