About this Abstract |
| Meeting |
Materials in Nuclear Energy Systems (MiNES) 2025
|
| Symposium
|
Materials in Nuclear Energy Systems (MiNES) 2025
|
| Presentation Title |
Dual-Beam Ion-Irradiation and Larger Heat Properties of Ni-Base Alloys for MSR/FHR Applications |
| Author(s) |
Ryan Thier, Jaimie Tiley, Ryan Gordon, Justin Hamil, Kumar Sridharan, Steven Zinkle |
| On-Site Speaker (Planned) |
Steven Zinkle |
| Abstract Scope |
Due to Hastelloy® N’s limited strength above 600°C, higher-creep-strength nickel alloys with adequate corrosion resistance are desirable to increase MSR/FHR concept upper operating temperatures and achieve improved thermodynamic efficiency and capital-cost reductions. Additionally, production of transmutant helium is expected to contribute to high-temperature embrittlement unless the gas atoms are successfully trapped at microstructural sinks. Vacuum-melted heats of two novel high-creep-strength precipitate-hardened Ni-Mo-7%Cr alloys have been industrially fabricated in several heat sizes up to 300 lb. The alloys are strengthened by carbide and gamma prime precipitates, respectively. Dual-ion irradiations have been performed with 8 MeV Ni+++ and 3.42 MeV He++ ions at 600°C to a nominal midrange damage level of 30 DPA. The Michigan Ion Beam Laboratory foil degrader system was utilized to provide a uniform He++ ion deposition throughout the region of interest, with two helium ratios: 3.5 appm He / DPA and 24 appm He / DPA to replicate typical fast and thermal spectrum reactor conditions. Differences in thermo-mechanical treatment and bulk mechanical properties between the heat sizes are briefly discussed. Post-irradiation strength changes are assessed using nanoindentation and Nix-Gao analysis. Microstructural changes in size and number density of second phases as well as He bubble density and morphology are examined with S/TEM-EDS techniques in the midrange safe analysis region. The helium interaction with pre-existing microstructural features and overall radiation resistance of the alloys will be discussed, along with recommendations for next steps towards deployment of these alloys. |
| Proceedings Inclusion? |
Undecided |