The design of High-Level radioactive Waste (HLW) repository in deep geological media shows that the highly compacted bentonite is a kind of ideal buffer material. Buffer materials between waste tank and the surrounding geological body is the last artificial barrier neighboring waste. The coupled Thermo-Hydro-Mechanical (THM) behaviors of the compacted bentonite are of importance for the HLW repository when operation and closed. This mock-up test was carried out to investigate the properties under THM coupled conditions, which will be helpful for the future design of engineered barrier system of China-mock-up. The characterization of compacted GaoMiaoZi (GMZ) bentonite related to swelling pressure, relative humidity and temperature are presented and interpreted.
The deep geological disposal for High-Level radioactive Waste (HLW) has been considered as an urgent worldwide environment issue. China pays more and more attentions to nuclear waste with the development of great economical growth. The long-term and reliable insulation from the human environment has raised worldwide attention for the countries who build nuclear power stations. Safe disposal of high level radioactive waste is a challenging task facing the scientific and technological world (Wang et al. 2006a). In order to safely dispose of the high-level radioactive waste generated from the nuclear power plants and other nuclear facilities, a number of disposal concepts have been developed in many countries, and results show that the deep geological disposal of High-Level radioactive Waste (HLW) is considered worldwide as the most safe and feasible method to protect human being and environment for tens of thousands years (Zhang et al. 2006). The behavior of HLW repository is determined, to a large extent, by the characteristics of the design and construction of the engineered barriers and especially by the changes that may occur in the mechanical, hydraulic, and geochemical properties as a result of the combined effects of heat generated by the radioactive decay and of the water and solutes supplied the surrounding rock (Villar et al. 2012). The concept design of repository in different geological formations generally relies on a multi-barrier system, which typically comprises the natural geological barriers provided by the repository host rock and an engineered barrier system (Liu & Wen 2003; Wang 2010).