NSUF 23-4747: Characterization of Manganese-Nickel Rich Precipitates and Their Interaction with Dislocations in Irradiated Reactor Pressure Vessel Steels
Major concerns for light water reactor life extensions involve neutron irradiation induced hardening and embrittlement in reactor pressure vessel (RPV) steels. At high fluence Mn-NI rich precipitates (MNPs) form at dislocation lines causing hardening and embrittlement in RPV steels. In this project we propose to analyze MNPs with different fluences and temperatures using transmission electron microscopy (TEM). The data from this experiment will show the evolution of dislocation structures under irradiation and behavior of unpinned and MNP pinned dislocations. Recent studies have shown that MNP precipitation change dislocation segments and causes local hardening. Coupling nanoindentation and TEM, the hardening and ductile-brittle-temperature-transition (DBTT) contributions due to the interaction between MNPs and dislocation segments will be characterized. By having this necessary data, a high fluence embrittlement prediction model can be implemented in order to analyze the lifespan of RPV steels. To provide insight on the evolution of dislocations and MNPs under irradiation, four RPV samples that were irradiated to varying fluences at different temperatures as part of UCSB ATR-2 irradiation campaign. These specimens will allow examination of dislocations and sizes of MNPs at different temperatures. The completion of this project will produce a model capable of predicting RPV behavior at extended life fluences (˃1x10^20 n/cm^2).
Additional Info
| Field | Value |
|---|---|
| Abstract | Major concerns for light water reactor life extensions involve neutron irradiation induced hardening and embrittlement in reactor pressure vessel (RPV) steels. At high fluence Mn-NI rich precipitates (MNPs) form at dislocation lines causing hardening and embrittlement in RPV steels. In this project we propose to analyze MNPs with different fluences and temperatures using transmission electron microscopy (TEM). The data from this experiment will show the evolution of dislocation structures under irradiation and behavior of unpinned and MNP pinned dislocations. Recent studies have shown that MNP precipitation change dislocation segments and causes local hardening. Coupling nanoindentation and TEM, the hardening and ductile-brittle-temperature-transition (DBTT) contributions due to the interaction between MNPs and dislocation segments will be characterized. By having this necessary data, a high fluence embrittlement prediction model can be implemented in order to analyze the lifespan of RPV steels. To provide insight on the evolution of dislocations and MNPs under irradiation, four RPV samples that were irradiated to varying fluences at different temperatures as part of UCSB ATR-2 irradiation campaign. These specimens will allow examination of dislocations and sizes of MNPs at different temperatures. The completion of this project will produce a model capable of predicting RPV behavior at extended life fluences (˃1x10^20 n/cm^2). |
| Award Announced Date | 2023-09-14T13:42:13.443 |
| Awarded Institution | None |
| Facility | None |
| Facility Tech Lead | Kory Linton, Yong Yang |
| Irradiation Facility | None |
| PI | Brandon Bohanon |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | None |