The Effect of Proton Irradiation on the Corrosion Behaviors of Ferritic/Martensitic Steel in Liquid Metal Environment

Ferritic-martensitic steel (FMS), which contains 9-12 wt.% of chromium, is being considered as an attractive candidate material for a fuel cladding of a sodium-cooled fast reactor (SFR) due to their high thermal conductivity, low thermal expansion coefficient, and excellent irradiation resistances to void swelling compared to austenitic stainless steels. Gr. 92 steel (9Cr-0.5Mo-1.8W-VNb) is the one of advanced versions of high chromium steels that was developed in the early 1990s. It has a higher creep-rupture strength than predecessors, 9Cr-1Mo steel and Gr. 91 steel (9Cr-1Mo-VNb). Thus, it is suitable for high temperature applications in advanced reactors since it can be used even above 650°C. While nuclear reactor is under operation, structural materials of cladding have been irradiated by neutron as well as various types of ion beams which can induce some damage on the material. Proton irradiation has been used for the past few decades to simulate neutron damages, because protons have a higher scattering cross-section than fast neutrons and it can form displacements This study is aimed at investigating the irradiation effects on corrosion behavior of FMS using accelerated technique, the proton irradiation, to understand irradiation situation of cladding materials during its life time inside of the core. The non-irradiated and irradiated FMS materials were used for corrosion and dissolution experiments. Through the experiments, it was observed that the irradiated materials exhibit worse corrosion and dissolution compared to the non-irradiated one. (author)