Corrosion mechanisms of potential container materials for the deep geological disposal of high-level radioactive waste (Corrosion mechanisms of potential container materials for the deep geological disposal of high-level radioactive waste)

A suitable site is being sought in Germany for the final disposal of high-level radioactive waste, such as spent fuel elements from nuclear power plants. Internationally, deep geological disposal is considered the preferred solution. This concept is based on a multi-barrier system designed to ensure the safe confinement of waste for up to a million years. The technical barriers include the container and a surrounding buffer medium. Possible container materials under discussion include copper, ductile iron and stainless steel; possible buffer media include swellable clay (bentonite) and cement. In addition to the technical components, geological conditions such as local hydrogeology and host rock also play a key role.
The Mineralogy Working Group is investigating the corrosion behaviour of potential container materials and their interaction with the buffer medium as part of its research into final storage. The experiments are carried out under application-oriented conditions in specially developed test setups. Comprehensive pre- and post-characterisation using complementary methods enables changes in the materials to be tracked in detail. The methods used include X-ray diffractometry, scanning electron microscopy, Raman spectroscopy, µ-X-ray fluorescence analysis and light microscopy.