Research Progress in High-level Waste Treatment and Disposal at China Institute of Atomic Energy

The treatment and disposal of high-level waste (HLW) are the main factors limiting the sustainable development of nuclear energy in China. The HLW research team at the China Institute of Atomic Energy is devoted to develope HLW treatment and disposal technologies. The main research progress of China Institute of Atomic Energy in recent years in liquid HLW vitrification, solid HLW immobilization, and HLW geological disposal presented was summarized in this paper. Regarding liquid HLW vitrification, a “two-step” cold crucible induction melter (CCIM) technology has been developed, with the establishment of processing techniques, main technological equipment, and preliminary numerical modeling, coupled with glass formulations suitable for various HLW sources. For solid HLW immobilization, a glass-ceramic immobilization route and an alloy smelting immobilization route have been developed for high-level halide waste and high-level metallic waste, respectively. In both cases, the immobilizing matrices and production conditions have been intensively investigated. In terms of HLW disposal, a series of research apparatuses for nuclide migration experiments under simulated deep geological repository conditions have been established. Together with analytical methods for measuring extremely low concentrations of nuclides in groundwater, massive data and characteristics of nuclide adsorption, dispersion, and diffusion in various scenarios have been obtained. These provide powerful support for establishing migration models to predict nuclide migration behavior over hundreds of thousands of years in deep geological environments.