Corrosion of A316L and T91 materials in liquid lead bismuth eutectic at temperatures 400-600°C

Lead bismuth eutectic (LBE) has been selected as coolant and spallation neutron source for the accelerator driven system (ADS) MYRRHA due to its good thermo hydraulic and nuclear properties. However liquid lead and especially bismuth can pose corrosion problems at elevated temperatures. The corrosion of materials exposed to liquid metals are classified in two major groups: general corrosion to which belong uniform and preferential dissolution, and oxidation and localized liquid metal corrosion comprising liquid metal embrittlement. The later may appear when material exposed to liquid metal is additionally stressed and is subject of another study. In this paper, general corrosion effects or particularly uniform dissolution and penetration and selective dissolution were investigated in stagnant liquid metal under 5%H2+Ar cover gas atmosphere in the temperature regions 400-600°C. At temperature greater than 500°C, time and temperature dependence of the corrosion process was observed. Three corrosion modes were distinguished: stable oxide mode characterized with thin protective oxide scale, transition mode featuring degradation of the initially formed oxide scale, and final dissolution corrosion mode during which both materials were subjected to intensive penetration and alloying elements dissolution. At lower temperatures (