Abstract
AISI 316H stainless steel, utilized in UK’s Advanced Gas-cooled Reactors (AGR), operates under conditions where creep, oxidation, and carburisation may occur, potentially leading to environmentally assisted cracking. It is important that such degradation mechanisms can be accounted for in both the design and lifetime management of affected plants. Previous studies have demonstrated the formation of cracks associated with carburisation and creep when the material is exposed to a simulated AGR gas at 550°C. This study investigates the effects under the same environmental conditions, focusing on the process zone ahead of the crack tip using samples pre-notched with a 130 µm diamond wire saw and subjected to creep in a simulated AGR gas environment. The results infer a cyclic process, driven by the interaction of creep cavitation and oxidation, and possibly further assisted by carburisation, which results in intergranular crack initiation and deep intergranular fractures that penetrate multiple grain boundaries. The results also highlighted enhanced oxidation of grain boundaries ahead of the notch tip, likely due to cavitation or void formation under creep
conditions.
conditions.
| Original language | English |
|---|---|
| Title of host publication | 22nd International Conference on Environmental Degradation of Materials in Nuclear Power Systems |
| Publication status | Accepted/In press - 6 Aug 2025 |
Keywords
- AISI 316H stainless steel
- creep
- oxidation
- carburisation
- environmentally assisted cracking