Engineered barrier experiments and analytical studies on coupled thermal-hydraulic-chemical processes in bentonite buffer material

Suzuki, Hideaki; Fujisaki, Kiyoshi*; Fujita, Tomoo 

The numerical analysis model was developed that understand the coupled thermal - hydraulic - mechanical - chemical (THMC) processes in the near field of high-level radioactive waste (HLW) repository after emplacement of the engineered barrier system (EBS). This paper is focusing on measured data of the experiments and calculated results of the THC model which were carried out for the period of 830 days. It was found that the information about the geochemical reaction and the mass transfer in the buffer material was obtained; pH distribution of pore water, precipitation of the secondary mineral etc. It was also indicated that the temperature and water content in the buffer material and mineral dissolution/precipitation in a contact surface of buffer material and mortar could be represented by the developed numerical model.