Corrosion behaviour of 12Cr-ODS steel in molten lead

Oxide dispersion-strengthened (ODS) steels are being studied as potential materials for future Generation IV concepts of Nuclear Fast Reactors. In particular, the use of heavy liquid metals (HLM), lead and lead bismuth eutectic alloy, is foreseen as coolant and target. However, most of the structural materials used traditionally, suffer severe damage when in contact with HLMs. Structural materials such as the austenitic 316L and the ferritic-martensitic T91 steels have been considered for operation at temperature lower than 823 K. On the other hand, for operations at elevated temperature and under severe neutron exposure environment, the ODS steels are taken into account and currently studied. In the frame of the FP7-GETMAT (Generation IV and Transmutation Materials) project, ODS steels containing 12 wt% Cr were tested in different conditions and environments, comparing experimental techniques and results. This paper reports the results of the study on the behaviour of the 12Cr-ODS steel in contact with molten lead at the temperature of 923 K. The corrosion tests were performed both in a static cell (CorAL) and in flowing conditions, in a natural convection loop (COLONRI II), in Pb, for an exposure time up to 2000 h. The microstructure analysis of the specimens was done before and after the corrosion tests. The results of the corrosion experiments in both experimental facilities are described and the characteristics of the oxides developed on the 12Cr-ODS steel are discussed.