The resistance of pure copper to stress corrosion cracking in repository environments

The risk for stress corrosion cracking (SCC) of the copper canister in the final repository for high-level radioactive waste in Sweden is low. However, it is a desire to try to elucidate and if possible quantify this minor risk. Available information from others and own work is discussed together with possible methods to estimate the resistance of pure copper to SCC in repository environments. An attempt to rationalise available crack growth rate data is made. Electrochemically controlled slow strain rate testing of pure copper was performed in a sodium nitrite solution, known to give SCC, and in a synthetic groundwater of pH 9. For reasons of comparison, testing was also performed in air. Whereas the occurrence of SCC as expected was clear in the sodium nitrite solution, it cannot be claimed that SCC has occurred in the synthetic groundwater