Sensitive THM coupled analysis of buffer-rock barriers for nuclear waste storage. In Unsaturated Soil Mechanics from Theory to Practice

The buffer-rock barriers system is widely proved to be one of the most promising options forisolating high-level radioactive waste from the human environment. To certify the efficiency and provide theadditional development regarding design and assessment of this barriers system, it is essential to understandthe complex Thermo-Hydro-Mechanical (THM) behavior of confining buffer under a variety of environmentalconditions. To this end, a case of buffer-rock barriers system is studied using a THM finite element approach.The contributions of different processes, including the vapor diffusion process, the water saturation dependentthermal conductivity and specific heat capacity as well as the temperature dependent water properties, involvedin the TH couplings are investigated in details. Based on all the simulation results, the key factors of design andassessment of buffer-rock barriers system are also analyzed