The Nuclear Waste Management Organization (NWMO) was established in 2002 under the Nuclear Fuel Waste Act (NFWA) to investigate approaches for managing Canada's used nuclear fuel. Currently, nuclear power plants are operating or undergoing decommissioning in Ontario, Quebec, and New Brunswick. Canada's CANDU reactors generate used fuel with small amounts of fissile nuclides compared to other types of nuclear reactors, owing to the use of unenriched uranium as a fuel source; used nuclear fuel is currently planned for disposal without reuse/reprocessing. The present approach, shown in Figure 1, envisions the conceptual long term storage of radioactive fuel bundles in specially designed canisters. The canisters would be emplaced in the rock of a suitable geological formation at a minimum of 500 m of depth, for an intended lifespan of more than 100,000 years (i.e., indefinite storage). The Canadian spent fuel canister consists of an inner container of steel strong enough to withstand geological pressures, including glaciations scenarios, and an outer shell of copper for corrosion resistance.