Confidence in Safety - South Bruce Site - 2023 Update

The key components of the repository are: the waste form (i.e., used nuclear fuel); the engineered barrier systems, notably the used fuel container and clay seals; the host rock; the underground repository facilities, notably the shafts, main services area, and the placement rooms connected by access tunnels; and the main surface facilities, where fuel is received, packaged, and transfer. [...] This confidence is built on our understanding of the following aspects: the characteristics of the geology of the South Bruce Site that provide containment and isolation; the long-term stability of the geosphere; the low risk of future human intrusion into the repository; the site is amenable to characterization; the robustness of the multiple barrier system; the repository can be cons. [...] The mineralogy of the rock, and the geochemical composition of the groundwater and rock porewater at repository depth should not adversely impact the expected performance of the repository multiple-barrier system. [...] The difference in depth to the top of the Cobourg Formation is a function of the varying surface topography and the gentle west-southwest inclination of the sedimentary layers at the site scale. [...] The overall thickness of the Ordovician aged rocks encountered in the boreholes beneath the site, and the drilled depth to the top of the Cobourg Formation, are within metres of the predictions based on the regional model of Carter et al.