Stress corrosion of alloy 600: influence of the mechanical load

In the PWR type reactors the steam generators formed of tubes in alloy 600 are very sensitive to stress intergranular corrosion in primary coolant circuits (lithium hydroxide and boric acid). The mechanical parameter traditionally used to describe the stress corrosion is the stress. The mechanical studies of the corrosion suggest that the deformation speed should be a determinant parameter. Moreover there is no correlation between macroscopic cold flow and stress corrosion. The two studies are made: stress corrosion and intergranular localised cold flow, the result of which is that the cold flow is localised at the grain joint, and the behaviour in cold flow might be modified by the atmosphere presence. 2 refs., 2 tabs