NSUF 16-625: Understanding the effects of irradiation dose rate and particle type in Ferritic/Martensitic alloys
The objective of this project is to understand the microstructural effects of irradiation across three dose rates, achieved by using three different irradiating particles, in ferritic/martensitic alloys. Ferritic/Martensitic (F/M) alloys offer high strength and dimensional stability upon irradiation, which make them leading candidates for structural and fuel cladding applications for advanced nuclear reactor designs. Proton and self-ion irradiations are increasingly being used to emulate neutron damage in these materials, in order to examine high irradiation doses in relatively short amounts of time and for lower cost. Worldwide, significant ongoing efforts seek to compare the effects of irradiation in F/M alloys between neutron and proton or between neutron and self-ion irradiation. However, to our awareness, there have been no studies that directly compare the irradiation response of identical heats of F/M alloys between all three irradiating particle types – neutrons, protons, and self-ions – at an otherwise fixed temperature and dose.This project will focus on commercial F/M alloys HCM12A and HT9, which have been irradiated to 3 displacements per atom (dpa) at 500°C using either 2.0 MeV protons, 5.0 MeV Fe++ self-ions, or a fast neutron spectrum. Previous NSUF rapid turnaround experiments have supported the microstructural characterization of the neutron- and proton-irradiated specimens. Differences in the morphology of irradiation-induced nanoclusters of Si, Mn, Ni, Cu, and Cr-rich as measured by atom probe tomography (APT) have been observed. Proton irradiation produced coarser nanoclusters that were on average ~3 times larger, but with a number density ~10 times lower, than did neutron irradiation. Additionally, neutron irradiation produced Cr-rich clustering, while proton irradiation did not show any evidence of Cr-rich clustering. Meanwhile, the evolution of dislocation loops and voids were comparable between proton and neutron irradiations.The proposed project will focus on specimens of HCM12A and HT9 alloys that have been irradiated to the following conditions: (1) 5.0 MeV Fe++ ions, 3 dpa, 500°C (2) 5.0 MeV Fe++ ions, 100 dpa, 500°CHaving the same alloy heats irradiated with three different particles, but to otherwise identical conditions, is a rare and unique opportunity offered by this project, and it can potentially provide tremendous insight into the mechanistic differences between irradiation damage caused by neutrons, protons, and self-ions. However, since 3 dpa is much lower than the hundreds of dpa that F/M components in advanced reactors are likely to receive, irradiation #2 will provide us with insight into the long-term stability and evolution of the irradiated microstructure.This project presents a significant opportunity to compare neutron, proton, and self-ion irradiation effects in identical heats of F/M alloys at identical irradiation temperatures and doses. The results of this project will help us gain a deeper understanding of the mechanisms of Si-Ni-Mn, Cu, and Cr clustering, and will be relevant to all F/M and other nanocrystalline alloys based on the b.c.c, Fe-Cr matrix, which are of growing interest to the Department of Energy Office of Nuclear Energy, due to their enhanced radiation resistance.
Additional Info
| Field | Value |
|---|---|
| Abstract | The objective of this project is to understand the microstructural effects of irradiation across three dose rates, achieved by using three different irradiating particles, in ferritic/martensitic alloys. Ferritic/Martensitic (F/M) alloys offer high strength and dimensional stability upon irradiation, which make them leading candidates for structural and fuel cladding applications for advanced nuclear reactor designs. Proton and self-ion irradiations are increasingly being used to emulate neutron damage in these materials, in order to examine high irradiation doses in relatively short amounts of time and for lower cost. Worldwide, significant ongoing efforts seek to compare the effects of irradiation in F/M alloys between neutron and proton or between neutron and self-ion irradiation. However, to our awareness, there have been no studies that directly compare the irradiation response of identical heats of F/M alloys between all three irradiating particle types – neutrons, protons, and self-ions – at an otherwise fixed temperature and dose.This project will focus on commercial F/M alloys HCM12A and HT9, which have been irradiated to 3 displacements per atom (dpa) at 500°C using either 2.0 MeV protons, 5.0 MeV Fe++ self-ions, or a fast neutron spectrum. Previous NSUF rapid turnaround experiments have supported the microstructural characterization of the neutron- and proton-irradiated specimens. Differences in the morphology of irradiation-induced nanoclusters of Si, Mn, Ni, Cu, and Cr-rich as measured by atom probe tomography (APT) have been observed. Proton irradiation produced coarser nanoclusters that were on average ~3 times larger, but with a number density ~10 times lower, than did neutron irradiation. Additionally, neutron irradiation produced Cr-rich clustering, while proton irradiation did not show any evidence of Cr-rich clustering. Meanwhile, the evolution of dislocation loops and voids were comparable between proton and neutron irradiations.The proposed project will focus on specimens of HCM12A and HT9 alloys that have been irradiated to the following conditions: (1) 5.0 MeV Fe++ ions, 3 dpa, 500°C (2) 5.0 MeV Fe++ ions, 100 dpa, 500°CHaving the same alloy heats irradiated with three different particles, but to otherwise identical conditions, is a rare and unique opportunity offered by this project, and it can potentially provide tremendous insight into the mechanistic differences between irradiation damage caused by neutrons, protons, and self-ions. However, since 3 dpa is much lower than the hundreds of dpa that F/M components in advanced reactors are likely to receive, irradiation #2 will provide us with insight into the long-term stability and evolution of the irradiated microstructure.This project presents a significant opportunity to compare neutron, proton, and self-ion irradiation effects in identical heats of F/M alloys at identical irradiation temperatures and doses. The results of this project will help us gain a deeper understanding of the mechanisms of Si-Ni-Mn, Cu, and Cr clustering, and will be relevant to all F/M and other nanocrystalline alloys based on the b.c.c, Fe-Cr matrix, which are of growing interest to the Department of Energy Office of Nuclear Energy, due to their enhanced radiation resistance. |
| Award Announced Date | 2015-12-16T00:00:00 |
| Awarded Institution | Center for Advanced Energy Studies |
| Facility | Microscopy and Characterization Suite |
| Facility Tech Lead | Yaqiao Wu |
| Irradiation Facility | None |
| PI | Matthew Wrong Swenson |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | 625 |