Hydrogen absorption in copper as a result of corrosion reactions in sulphide and chloride containing deoxygenated water at 90 °C in simulated spent nuclear fuel repository conditions

Recently, copper corrosion in anoxic conditions in pure water has been claimed to take place by hydrogen evolution. Part of this hydrogen is expected to absorb in copper. However, the most important source of hydrogen in copper is sulphide corrosion, which is the main form of copper corrosion during the long-term deposition of spent nuclear fuel. In this study stress corrosion cracking of copper in sulphide and chloride containing deoxygenated water was studied at 90 °C at sulphide concentrations from 0.001 to 0.00001 M using a slow strain rate testing (SSRT) method up to 9% strain. Intergranular cracks were detected in specimens exposed at 0.001 M sulphide concentration. Hydrogen is generated due to sulphide corrosion reactions and therefore the hydrogen content of SCC specimens was measured. A noticeable increase of hydrogen content in the copper specimens was observed even at the lowest sulphide level in the test. The occurrence of sulphide-induced SCC of copper in deoxygenated water is discussed based on hydrogen-enhanced intergranular cracking mechanism.