Connecting atom-scale bentonite clay models to macroscale mechanical and transport models for spent nuclear fuel storage
Bentonite is a naturally occurring clay containing montmorillonite, a smectic clay mineral that has a high cation exchange capacity and swells upon contact with water. The swelling capacity of bentonite limits movement of water which makes it an attractive candidate to be used as an engineered barrier system to protect used nuclear fuel containers that are stored in deep geological repositories. The Nuclear Waste Management Organization is responsible for Canada’s implementation of the plan for the long-term care of nuclear-spent fuel produced by Canadian nuclear reactors. The nuclear-spent fuel is to be deposited in steel canisters coated with 3 mm of corrosion-resistant copper and buried underground. In theory, temporal corrosion of copper is inhibited by the presence of bentonite. However, water and various ions can potentially reach the copper layer and disrupt its corrosion-resistance. The aim of this study is to use novel combination of the atomistic and mesoscale state-of-art methods to simulate the transport properties of water and various of ions in bentonite. The developed method will enable NWMO to better understand the transport through bentonite's pore network.