NSUF 25-5315: Investigating helium and hydrogen behavior in beryllium carbide at high temperature using in-situ ion irradiations
Graphite, a candidate moderator for advanced reactors, exhibits several problematic qualities. Extended radiation damage eventually leads to failure due to swelling and fracturing. Alongside this, fission products like hydrogen and helium produced during reactor operations further affect the swelling unpredictably. Alternative moderators like beryllium carbide (Be2C) may address the limited lifespan and efficiency observed in current materials. The antifluorite crystal structure is potentially more resistant to radiation damage compared to graphite. Be2C is a methanide and has been shown to chemically react with hydrogen to form methane. This trait suggests it may bond with tritium to form CH4 and control the level of diffusion in the reactor. The University of Michigan has the capability for handling and irradiating beryllium-based samples. A tandem ion accelerator and transmission electron microscope (TEM) are proposed to conduct in-situ TEM ion irradiations. In-situ TEM ion irradiations are ideal as they provide direct observation of nucleation and migration of bubbles throughout the experiment. The main outcome of this proposal will demonstrate the retention of hydrogen and helium in Be2C and understand the fundamental mechanism(s) around radiation damage as a moderator in advanced reactors. This technique will use pre-irradiated FIB milling to produce “lift-outs” of samples that will be mounted on a TEM grid. Two experiments will implant either helium or hydrogen with 450 appm and 1000 appm respectively at 500 ˚C. Defects will be tracked using the Theiascope™ machine learning automated detection system for the full duration of each experiment with a handful of frames counted manually to confirm the accuracy of the program. Post irradiation examination will be conducted on each sample with a focus on chemical mapping in several regions of the lift-out. Completion of the experiments will impact the material selection for moderators and aid the development and deployment of advance reactors.
Additional Info
| Field | Value |
|---|---|
| Awarded Institution | University of Michigan |
| DOI | 10.46936/NSUF/60015362 |
| Embargo End Date | 2027-09-03 |
| Facility Tech Lead | Kevin Field |
| Irradiation Facilities | Michigan Ion Beam Laboratory |
| NSUF Call | FY 2025 RTE 2nd Call |
| PI | Diego Muzquiz |
| PIE Facilities | Michigan Ion Beam Laboratory, Michigan Center for Materials Characterization |
| Prep Facilities | Michigan Ion Beam Laboratory |
| Project Member | Dr. Kevin Field, Associate Professor - University of Michigan (https://orcid.org/0000-0002-3105-076X) |
| Project Member | Dr. Stephen Raiman, R&D Associate - Corrosion Science - Oak Ridge National Laboratory (https://orcid.org/0000-0002-4801-5098) |
| Project Member | Mr Diego Muzquiz, Student - University of Michigan (https://orcid.org/0009-0001-4533-4130) |
| Project Type | RTE |