Importance of microscopic and theoretical research on bentonite-based buffers and backfills behavior

Bentonite-based buffers and backfills are the most significant key components for high-level radioactive waste (HLW) disposal projects worldwide. This review article briefly outlines previous studies on the fundamental properties of bentonite-based buffers and backfills from a microscopic and theoretical perspective. It also describes the design of specifications for buffers and backfills from a multidimensional perspective, covering characteristics such as swelling, self-sealing, very low hydraulic conductivity, and the filtration ability of montmorillonite mineral layers against cations. Montmorillonite is a major clay mineral of bentonite. Additionally, the author presents future research directions, such as the development of quantitative evaluation methods for the transition from unsaturated to saturated states. Consequently, this study emphasizes the importance of microscopic and theoretical approaches to understanding montmorillonite and bentonite.