About this Abstract |
| Meeting |
Materials in Nuclear Energy Systems (MiNES) 2025
|
| Symposium
|
Materials in Nuclear Energy Systems (MiNES) 2025
|
| Presentation Title |
In-Situ Investigation of Radiation-induced Cluster Evolution in Surveillance RPV Steels Under Varied Annealing Conditions |
| Author(s) |
Kun Wang, Tim Lach, Mikhail Sokolov, Xiang Chen |
| On-Site Speaker (Planned) |
Kun Wang |
| Abstract Scope |
Nanoscale solute-rich clusters or precipitates form in reactor pressure vessel (RPV) steels upon neutron irradiation during nuclear power plant operations, leading to significant hardening and embrittlement. Post-irradiation annealing (PIA) aims to dissolve or coarsen these clusters, potentially restoring mechanical properties. Traditionally, ex-situ isothermal annealing methods have been employed to investigate cluster evolution; however, these methods offer limited insight into dissolution kinetics and underlying mechanisms due to constraints on annealing conditions.
Recent advancements in specimen preparation and transmission electron microscopy (TEM) heating holders with enhanced mechanical and thermal stability now facilitate in-situ annealing experiments. This approach allows real-time observation of cluster evolution kinetics and mechanisms directly within the microscope.
In this study, we utilize an in-situ heating and gas TEM holder to perform real-time post-irradiation annealing on both base and welded RPV steels at temperatures of 340 °C and 450 °C for 24 hours. Scanning/transmission electron microscopy (S/TEM) combined with STEM-EDS mapping is employed to analyze changes in cluster size, number density, and elemental distributions at grain boundaries throughout the annealing process.
Our findings provide detailed time-related data on cluster evolution and elemental segregation at grain boundaries, enabling direct correlation with mechanical property changes, specifically hardness recovery. This in-situ approach enhances understanding of cluster dissolution and coarsening behaviors, informing strategies for mitigating embrittlement in irradiated RPV steels. |
| Proceedings Inclusion? |
Undecided |