Influence of coupled THM phenomena on the safety of a spent fuel repository; A Near-field study

Nguyen, T. S.*; Brgesson, L.*; Chijimatsu, Masakazu*; Fujita, Tomoo ; Hernelind, J.*; Jussila, P.*; Rutqvist, J.*; Jing, L.*

In order to demonstrate the feasibility of geological disposal of spent CANDU fuel in Canada, a safety assessment was performed for a hypothetical repository in the Canadian Shield. The assessment shows that such repository would meet international criteria for dose rate; however, uncertainties in the assumed evolution of the repository were identified. Such uncertainties could be resolved by the consideration of coupled Thermal-Hydro-Mechanical-Chemical (THMC) processes. In Task A of the DECOVALEX-THMC project, THM models will be refined and used to perform near-field simulations of the evolution of the repository in order to address the above uncertainties. This paper presents the definition and rationale of Task A and the preliminary results.