The extent of stress corrosion cracking (SCC) of copper nuclear waste containers is being predicted on the basis of a “limited propagation” argument. In this argument, it is accepted that crack initiation may occur, but it is argued that the environmental conditions and material properties required for a through-wall crack to propagate will not be present.
In this paper, the effect of one environmental parameter, the supply of oxidant (Jox), on the crack growth rate is examined. Experiments have been conducted on two grades of Cu in NaNO2 environments using two loading techniques. The supply of oxidant has been varied either electrochemically in bulk solution using different applied current densities or by embedding the loaded test specimens in compacted buffer material containing O2 as the oxidant. Measured and theoretical crack growth rates as a function of Jox are compared with the predicted oxidant flux to the containers in a disposal vault and an estimate of the maximum crack depth on a container obtained.