Kinetic modeling of IG-110 oxidation in inert atmosphere with low oxygen concentration for innovative high-temperature gas-cooled reactor applications.

The oxidation behavior of IG-110, a graphite core component, was investigated at temperatures ranging from 400 to 1000°C in a 10 ppm Ar/O₂ flow to simulate the oxidation process between the graphite core component and helium coolant with low O₂ concentrations employed in advanced High-Temperature Gas-cooled Reactors (HTGRs). The results reveal that IG-110 undergoes significant mass loss at temperatures above 700°C, resulting in total mass changes of −1.5%, −5.3%, and −9.0% at 700, 800, and 1000°C, respectively, during a 10-hour oxidation period. No significant mass loss is observed below 600°C. To understand the oxidation mechanism of IG-110 under low O₂ concentrations, we propose a kinetic model as the current chemical kinetic-controlled model does not fully explain the oxidation behavior observed in our research. Our analysis shows lower estimated reaction rates compared to studies at higher O₂ concentrations; the activation energy values exhibit good agreement. The proposed kinetic model sheds light on the oxidation mechanism of IG-110 under 10 ppm Ar/O₂ flow. This study provides new insights into the oxidation behavior of graphite core components in HTGRs and highlights the importance of controlling the O₂ concentration in the helium coolant to prevent severe degradation of SiC-matrix fuel compacts. [ABSTRACT FROM AUTHOR]