| About this Abstract |
| Meeting |
2025 TMS Annual Meeting & Exhibition
|
| Symposium
|
Steels in Extreme Environments
|
| Presentation Title |
CO2 Oxidation and Carburisation Evolution in Fe9Cr1Mo Steels for Advanced Gas-Cooled Reactors |
| Author(s) |
Peter James Thomas, Mariia Zimina, Lawrence Coghlan, Aya Shin, Jonathan Pearson, Peter E J Flewitt, Tomas Martin |
| On-Site Speaker (Planned) |
Peter James Thomas |
| Abstract Scope |
CO2 oxidation and carburisation are critical degradation mechanisms affecting the integrity of Fe9Cr1Mo steels in Advanced Gas-Cooled Reactors . This study explores the microstructural changes in these steels after prolonged exposure to high-temperature CO2 environments, focusing on the oxidation/carburisation front and breakaway oxidation behavior. Experimental studies were conducted under simulated reactor conditions and autoclave environments, utilizing techniques such as optical and electron microscopy, focused ion beam, and atom probe tomography. These methods revealed morphological changes, carbide precipitation, elemental segregation, and oxide scale growth. Notably, some specimens exhibited a "tube wall delay" (TWD) phenomenon, where oxidation rates slowed or arrested, contradicting existing literature. Proposed mechanisms driving the multi-stage CO2 oxidation and carburisation process are presented, with insights into potential new stages observed in TWD specimens. These findings aim to enhance the understanding and mitigation of degradation in reactor components. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Iron and Steel, Nuclear Materials, High-Temperature Materials |