NSUF 18-1210: Irradiation-induced solute clustering behavior in ferritic/martensitic alloy T91
The objective of this project is to evaluate the mechanism of irradiation-induced solute clustering in the ferritic-martensitic alloy T91 and confirm experimental temperature shift estimates when using charged-particles to emulate neutron irradiation. Ferritic/martensitic (F/M) alloys are leading candidates for structural and fuel cladding applications for advanced nuclear reactor designs due to their high strength and thermal conductivity. Furthermore, their high sink strengths provide resistance to irradiation-induced swelling and embrittlement. As such, it is critical to have a clear understanding of how the microstructures of these alloys will evolve with long-term irradiation. To date, studies evaluating nanocluster evolution in the commercial F/M alloys HCM12A and HT9 have exhibited variable nanocluster evolution of Cu-rich, Si-Mn-Ni-rich and Cr-rich nanoclusters after irradiation with protons, Fe2+ ions, or neutrons to otherwise common conditions of ~3dpa at 500°C.
A calculation method is developed to predict evolution of nanocluster radius over irradiation time based on the theory of Nelson, Hudson, and Mazey. It has been demonstrated mathematically that this calculation model may be used to isolate the clustering behavior for each solute species. Previous solute calculations (for HCM12A and HT9) have shown a strong correlation between solute dissolution efficiency and known literature values of displacement energy for various solutes. With this experiment, we will be able to test the capability of the NHM-based model as a predictive tool for solute cluster evolution, informing future F/M and nanofeatured alloy development. Additionally, the NHM-based model has enabled evaluation of the temperature shift requirements for higher dose irradiations through study of temperature sensitivity on the clustering evolution of several species of solutes upon various irradiation conditions. This experiment enables evaluation if temperature shift requirements on an additional alloy to inform future charged particle irradiation experiments for fast neutron emulation.
This project focuses on the commercial F/M alloy T91, irradiated separately to the following conditions: a) 2 MeV protons to 2.4 dpa at 500°C, b) 5 MeV Fe2+ ions to 3 dpa at 500°C, and c) 5 MeV Fe2+ ions to 100 dpa at 500°C. Characterization of samples irradiated to ~3 dpa enables direct comparison with previously analyzed specimens irradiated with fast neutrons (RTE 13-419) at the same dose and temperature. Subsequent calculations using the NHM model will validate the solute cluster evolution model and confirm the predicted temperature shift requirements to emulate nanocluster evolution in F/M alloys using higher dose rate irradiations. Finally, characterization of the specimen irradiated to 100 dpa (Fe2+ ions) will verify if solute redistribution at high dose is consistent across multiple F/M alloys with common solute species.
The project will accomplish two major goals: a) validation of our solute specific model of cluster evolution in irradiated b.c.c. Fe-based alloys, and b) confirm the temperature shift requirements for using higher dose irradiations. Each will provide valuable information for nanofeatured alloy development and charged particle irradiation experimentation, both of which are of growing interest to the Department of Energy Office of Nuclear Energy.
Additional Info
| Field | Value |
|---|---|
| Abstract | The objective of this project is to evaluate the mechanism of irradiation-induced solute clustering in the ferritic-martensitic alloy T91 and confirm experimental temperature shift estimates when using charged-particles to emulate neutron irradiation. Ferritic/martensitic (F/M) alloys are leading candidates for structural and fuel cladding applications for advanced nuclear reactor designs due to their high strength and thermal conductivity. Furthermore, their high sink strengths provide resistance to irradiation-induced swelling and embrittlement. As such, it is critical to have a clear understanding of how the microstructures of these alloys will evolve with long-term irradiation. To date, studies evaluating nanocluster evolution in the commercial F/M alloys HCM12A and HT9 have exhibited variable nanocluster evolution of Cu-rich, Si-Mn-Ni-rich and Cr-rich nanoclusters after irradiation with protons, Fe2+ ions, or neutrons to otherwise common conditions of ~3dpa at 500°C. A calculation method is developed to predict evolution of nanocluster radius over irradiation time based on the theory of Nelson, Hudson, and Mazey. It has been demonstrated mathematically that this calculation model may be used to isolate the clustering behavior for each solute species. Previous solute calculations (for HCM12A and HT9) have shown a strong correlation between solute dissolution efficiency and known literature values of displacement energy for various solutes. With this experiment, we will be able to test the capability of the NHM-based model as a predictive tool for solute cluster evolution, informing future F/M and nanofeatured alloy development. Additionally, the NHM-based model has enabled evaluation of the temperature shift requirements for higher dose irradiations through study of temperature sensitivity on the clustering evolution of several species of solutes upon various irradiation conditions. This experiment enables evaluation if temperature shift requirements on an additional alloy to inform future charged particle irradiation experiments for fast neutron emulation. This project focuses on the commercial F/M alloy T91, irradiated separately to the following conditions: a) 2 MeV protons to 2.4 dpa at 500°C, b) 5 MeV Fe2+ ions to 3 dpa at 500°C, and c) 5 MeV Fe2+ ions to 100 dpa at 500°C. Characterization of samples irradiated to ~3 dpa enables direct comparison with previously analyzed specimens irradiated with fast neutrons (RTE 13-419) at the same dose and temperature. Subsequent calculations using the NHM model will validate the solute cluster evolution model and confirm the predicted temperature shift requirements to emulate nanocluster evolution in F/M alloys using higher dose rate irradiations. Finally, characterization of the specimen irradiated to 100 dpa (Fe2+ ions) will verify if solute redistribution at high dose is consistent across multiple F/M alloys with common solute species. The project will accomplish two major goals: a) validation of our solute specific model of cluster evolution in irradiated b.c.c. Fe-based alloys, and b) confirm the temperature shift requirements for using higher dose irradiations. Each will provide valuable information for nanofeatured alloy development and charged particle irradiation experimentation, both of which are of growing interest to the Department of Energy Office of Nuclear Energy. |
| Award Announced Date | 2018-02-01T14:15:26.233 |
| Awarded Institution | None |
| Facility | None |
| Facility Tech Lead | Yaqiao Wu |
| Irradiation Facility | None |
| PI | Matthew Swenson |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | 1210 |