Uranium extraction from TRISO-coated fuel particles using supercritical CO2 containing tri-n-butyl phosphate

► New strategy for reprocessing of spent nuclear fuel from high temperature gas-cooled reactor was proposed. ► TRISO-coated fuel particles were crushed and heat treated to obtain U3O8 powder and SiC fragments. ► Mixture of U3O8 powder and SiC fragments was converted into mixture of uranyl nitrate and SiC fragments using liquid N2O4. ► Uranium was completely recovered from mixture of uranyl nitrate and SiC fragments using supercritical fluid.