(GRS 232) Modelling of Corrosion-Induced Processes in Emplacement Borehols and Drifts

There are a number of physical and chemical effects occurring in the near field of an underground repository with steel containers. Such containers tend to corrode under the influence of humidity, both in the presence and the absence of gaseous oxygen. While in clay the re-saturation of the host rock with liquid water is the normal evolution, a repository in salt is expected to remain dry, but a brine intrusion can never be completely ruled out.

Moreover, there is always some residual humidity in the salt backfill. Therefore, it should be assumed, that in all cases there is enough water available for corrosion. There are two kinds of iron corrosion. The aerobic iron corrosion process in the presence of elementary oxygen requires the presence of water without consuming it. The anaerobic iron corrosion process consumes water and produces hydrogen gas, transforming iron to magnetite.