Corrosion studies on non-metallic inorganic materials for HLW packaging design

Within the framework of our studies to find out suitable materials for developing HLW packaging with a barrier function in a salt repository the corrosion behavior was investigated of non-metallic inorganic materials under specified hypothetical accident conditions. Moreover glass solders to be used as connecting materials between canister and lid as an alternative closing technique have been tested for their corrosion behavior. The corrosion studies on ceramic materials and glass solders are performed in a quinary salt brine (Q-brine) at temperatures between 80 and 2000C and a pressure of 130 bar. The investigations have confirmed that some materials show a high corrosion resistance. The highest corrosion resistance was exhibited by the Al2O3 material. It decisively depends on the purity, the structure and the surface finish of the material. The glasses investigated at 2000C showed that the chemically resistant glass 8330 (19 μm/a at 2000C) and an HLW model glass with adapted dilatation coefficient (86 μm/a) exhibit a good resistance to corrosion. The results obtained so far have shown that development of HLW packaging with a barrier function in the repository can be generally achieved with the use of ceramic materials. (orig./RB)