Investigating effect of dose rate on microstructure evolution in 800H alloy at high doses
Principal Investigator
- Name:
- Xingyu Liu
- Email:
- [email protected]
- Phone:
- (208) 526-6918
Team Members:
| Name: | Institution: | Expertise: | Status: |
|---|---|---|---|
| Xing Wang | Pennsylvania State University | APT, Radiation Damage, Rate Theory, TEM | Faculty |
| Arthur Motta | Pennsylvania State University | Amorphization, Cladding, Corrosion, Hydrides, Intermetallic, Material Characterization, Material Degradation, Radiation Damage, Synchrotron, Zirconium, Zirconium Alloys | Faculty |
Experiment Details:
- Experiment Title:
- Investigating effect of dose rate on microstructure evolution in 800H alloy at high doses)
- Hypothesis:
- Our TEM analysis found that, compared to neutron irradiated 800H, ex-situ dual ion samples showed significantly fewer cavities (5nm-15nm in diameter) at doses > 47 dpa and rare Cr-rich M23C6 precipitates from 16 dpa to 81 dpa. The hypothesis for the different microstructures is that the high dose rate prevents the formation of Cr-rich precipitates, resulting in different local chemistry for cavities and thus suppressing the cavity formation under dual-ion irradiation.
- Work Description:
- Two in-situ irradiation 800H alloy foils will be prepared by using Focused Ion Beam (FIB) technique in Pennsylvania State University. The in-situ dual ion irradiation will be conducted in IVEM by using 1 MeV Kr ion and ~ 10 KeV He ion. The first in-situ sample will be irradiated at a dose rate of 1.5E-4 dpa/s at 480°C up to 30 dpa. The second in-situ sample will be irradiated at a dose rate of 1.0E-3 dpa/s at 480°C up to 50 dpa.
Technical Abstract
The proposed Rapid Turnaround Experiment (RTE) aims at elucidating the effect of dose rate on precipitate dissolution and the effect of local chemistry on the cavity formation at high doses. The microstructure evolution observed during in-situ dual ion irradiation will bridge the knowledge gap between neutron irradiation damage and dual ion irradiation damage at high doses. By leveraging the newly established in-situ dual ion irradiation capability in Intermediate Voltage Electron Microscope (IVEM) facility at Argonne National Laboratory, we aim to unravel the interactions between radiation-induced precipitates and cavities and establish fundamental understandings of dose-rate effects on defect evolution in 800H alloys, thus enabling more accurate emulation of neutron damage using accelerated ion irradiation.
Relevance
A significant obstacle to accelerating the deployment of advanced nuclear reactors and extending the operation of existing ones is the lack of sufficient data on the performance of core structural materials at high doses. To expedite the qualification process for promising structural materials, faster irradiation methods, such as heavy ion irradiation, are essential. However, accurately emulating neutron damage with ion irradiation presents challenges due to gaps in understanding the mechanisms of microstructure evolution at various doses and high dose rates.
To address this knowledge gap, we will utilize in-situ dual-ion irradiation to characterize defect evolution in 800H alloy at different dose rates and high doses. 800H is a promising austenitic steel for both light water reactors and advanced reactors, and it serves as a benchmark material for understanding fundamental mechanisms. Our focus will be on cavities and precipitates, two key defect structures that significantly impact material performance. The in-situ irradiation will allow us to correlate the kinetics of these defects both spatially and temporally, providing insights into the coupled effects of dose rates on defect evolution.
Our research will directly support two of the DOE-NE goals:
Enable the continued operation of existing U.S. nuclear reactors.
Enable the deployment of advanced nuclear reactors.
The findings from this study will also support an ongoing NEUP IRP project that aims to emulate neutron damage using dual-ion irradiation.
To address this knowledge gap, we will utilize in-situ dual-ion irradiation to characterize defect evolution in 800H alloy at different dose rates and high doses. 800H is a promising austenitic steel for both light water reactors and advanced reactors, and it serves as a benchmark material for understanding fundamental mechanisms. Our focus will be on cavities and precipitates, two key defect structures that significantly impact material performance. The in-situ irradiation will allow us to correlate the kinetics of these defects both spatially and temporally, providing insights into the coupled effects of dose rates on defect evolution.
Our research will directly support two of the DOE-NE goals:
Enable the continued operation of existing U.S. nuclear reactors.
Enable the deployment of advanced nuclear reactors.
The findings from this study will also support an ongoing NEUP IRP project that aims to emulate neutron damage using dual-ion irradiation.
Research Report