Abstract

Progress in development of glass formulas for vitrifying ZrO2- and MoO3-bearing high level liquid waste

Progress in development of glass formulas for vitrifying ZrO2- and MoO3-bearing high level liquid waste

Shengheng Tan*1, Jiong Chang 1, Jiateng Wang 1, Cheng, He 1, Hua Zhang 1

1 Department of Radiochemistry, China Institute of Atomic Energy, 1 Sanqiang Road, Xinzhen, Fangshan, Beijing, China.

On the development of cold crucible induction melter (CCIM) technology for high level liquid waste (HLLW) vitrification in China, a full scale research prototype of CCIM has recently been established by China Institute of Atomic Energy. The major systems, including an induction melter, a rotary kiln and a simplified off-gas treatment system, have been successfully tested for a 240-hour continuous operation in September 2022. About 6 t glass wasteforms at a targeted HLLW loading of 20 wt% were produced at a production rate of 25 kg/h, equivalent to a ~90 L/h of HLLW treatment capacity. The processing arts of melter starting-up, HLLW calcining, calcine feeding, glass melting, melt stirring, periodic pouring and system re-start have been validated during the test and the properties of the glass products are proven to have met the requirements for geological disposal. The glasses have shown excellent chemical durability and thermal stability; especially, the abundant elements in HLLW, such as Mo, Zr and Ln, are not prone to crystallize from glass melts during the heat treatment. Following the success of the test, a full scale engineering prototype of CCIM is under establishment and is scheduled for a longer-term (2000 h) continuous operation in 2023.