NSUF 23-4724: Visualizing the root cause of dislocation channel broadening through in-situ TEM experiments
While radiation hardening is considered as one major mechanistic factor for higher irradiation-assisted stress corrosion cracking (IASCC) in austenitic stainless steels (SS), our recent data comparing three forms of 316L SS suggests that excellent IASCC resistance can be obtained from the one with the highest radiation hardening, in this case an additively-manufactured (AM) 316L SS after hot isostatic pressing (HIP). The study further confirmed dislocation channel broadening is possibly the underlying mechanism by reducing the stress localization at the dislocation channel – grain boundary intercepts. We hypothetically believe that the size, density, and distribution of radiation induced defects (voids, loops, precipitates), acting as weak dispersed barriers, affect the channel behavior. This proposed RTE experiment is designed to obtain direct experimental observation to confirm this hypothesis. By correlating the dislocation movement to the defect distribution, the work directly visualizes how different defect distributions contribute to channel broadening, which will also be further compared to a channel broadening simulation. The contributions of this work to the state-of-the-knowledge are two folds: first, the study reveals the mechanistic origin of the superior IASCC resistance of HIP’ed AM 316L SS as compared to wrought counterpart. This learning is critical for AM 316L SS qualification for nuclear use; second, more importantly, the work outlines the possible conditions where the traditional belief of the radiation hardening vs. IASCC susceptibility relationship is not valid. EPRI and the utilities are considering radiation hardening as an important measure for IASCC management. The understandings from this research contribute to the overall reactor safety and maintenance for both existing light water reactors and future small-modular reactors.
Additional Info
| Field | Value |
|---|---|
| Abstract | While radiation hardening is considered as one major mechanistic factor for higher irradiation-assisted stress corrosion cracking (IASCC) in austenitic stainless steels (SS), our recent data comparing three forms of 316L SS suggests that excellent IASCC resistance can be obtained from the one with the highest radiation hardening, in this case an additively-manufactured (AM) 316L SS after hot isostatic pressing (HIP). The study further confirmed dislocation channel broadening is possibly the underlying mechanism by reducing the stress localization at the dislocation channel – grain boundary intercepts. We hypothetically believe that the size, density, and distribution of radiation induced defects (voids, loops, precipitates), acting as weak dispersed barriers, affect the channel behavior. This proposed RTE experiment is designed to obtain direct experimental observation to confirm this hypothesis. By correlating the dislocation movement to the defect distribution, the work directly visualizes how different defect distributions contribute to channel broadening, which will also be further compared to a channel broadening simulation. The contributions of this work to the state-of-the-knowledge are two folds: first, the study reveals the mechanistic origin of the superior IASCC resistance of HIP’ed AM 316L SS as compared to wrought counterpart. This learning is critical for AM 316L SS qualification for nuclear use; second, more importantly, the work outlines the possible conditions where the traditional belief of the radiation hardening vs. IASCC susceptibility relationship is not valid. EPRI and the utilities are considering radiation hardening as an important measure for IASCC management. The understandings from this research contribute to the overall reactor safety and maintenance for both existing light water reactors and future small-modular reactors. |
| Award Announced Date | 2023-06-01T09:02:02.383 |
| Awarded Institution | None |
| Facility | None |
| Facility Tech Lead | Wei-Ying Chen |
| Irradiation Facility | None |
| PI | Jingfan Yang |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | None |