Investigation on boron carbide oxidation for nuclear reactor safety: Experiments in highly oxidising conditions

The oxidation kinetics of boron carbide pellets were investigated in steam/argon mixtures in the temperature range 1200–1800 °C for steam partial pressures between 0.2 and 0.8 bar and total flows (steam + argon) between 2.5 and 10 g/min resulting in gas velocities from 1.01 to 5.34 m/s. A kinetic model for boron carbide pellet oxidation depending on temperature, steam partial pressure and flow velocity is obtained. The activation energy of the oxidation process was determined to be 163 ± 8 kJ/mol. The strong influence of temperature and steam partial pressure on the boron carbide oxidation kinetics is confirmed. The obtained data suggest the coexistence of two kinetic regimes, one at 1200 °C and the other at 1400–1800 °C, with different dependence on steam partial pressure.