Investigating the effect of bentonite compaction density and environmental conditions on the corrosion of copper materials

The proposed long-term management plan for used nuclear fuel is to isolate it within a multiple-barrier system underground in deep geological repository (DGR). In the Canadian design, bundles will be sealed copper-coated carbon steel containers, encased blocks of bentonite clay, emplaced approximately 500–800 m below ground, and surrounded by gapfill material. A laboratory experimental campaign has been undertaken demonstrate integrity system. DGR-relevant copper materials were embedded compacted various densities, into hermetic pressure vessel pressurized with demineralized water. Experiments explored influence compaction range 1100–1600 kg/m3 on corrosion over durations 1–18 months. Postexposure analysis coupons showed nonhomogeneous corrosion, products composed Cu2O, some Cu2S. average rates decreased as function time increasing density. general, we observed that higher density suppressed copper.