High temperature performance of austenitic stainless steels in impure Helium environment

Historical evidence highlights the significant impact of impurities, such as H2, CO, and H2O, on the degradation of structural materials exposed to high-temperature helium environments. Stainless steels and Alloy 800H are expected to serve as structural materials in High-Temperature Gas Reactors (HTGR). This degradation, influenced by impurities, subsequently affects the mechanical properties of HTGR structural components. Additionally, surface treatment plays a crucial role in material degradation for these structural materials. However, limited research on impure helium environments has resulted in a scarcity of materials data. This PhD research delves into the effects of impurities and surface finishes under impure helium conditions, exploring their impact on HTGR structural material degradation behavior and mechanical properties