Glass-ceramic composite wasteform to immobilize and stabilize a uranium-bearing waste generated from treatment of a spent uranium catalyst

Abstract A disposal method for radioactive waste should be carefully chosen on a case-by-case basis, taking into consideration, chemical and radiological properties of the waste, acceptance criteria required for disposal site, and circumstance of the country where the waste is generated. A large volume of uranium-bearing waste (UO 2 -Sb 2 O 3 -Fe 2 O 3 -SiO 2 mixture oxide) from to be finally disposed will be generated from a process to treat spent uranium catalyst in South Korea. This worked studied a glass-ceramic composite wasteform tailor-made for the final uranium-bearing generated from the process. The physicochemical properties of the prepared glass-ceramic wasteform were evaluated to ensure that the waste acceptance criteria for a disposal site in South Korea could be met. The mechanism of forming the glass-ceramic matrix and its final structure were investigated by using TG-DSC, SEM-EDS and XRD. The optimal sintering temperature and content of B 2 O 3 to be added were 1100 °C and approximately 2–3 wt % in the total uranium-bearing waste, respectively. The SiO 2 , Fe 2 O 3 and Sb 2 O 3 in the target uranium-bearing waste formed a glass phase with help of B 2 O 3 , and SbFeO 4 oxide phase, respectively. Both UO 2 and Al 2 O 3 , which exhibit high melting points, remained as refractory phases in the sintered body. Conversion of the uranium-bearing waste into a glass-ceramic composite matrix wasteform was confirmed to be an effective way to deal with the uranium-bearing waste in terms of volume reduction of the waste and waste acceptance criteria for the disposal site in Korea.