About this Abstract |
| Meeting |
Materials in Nuclear Energy Systems (MiNES) 2025
|
| Symposium
|
Materials in Nuclear Energy Systems (MiNES) 2025
|
| Presentation Title |
Investigation of ZrC Microstructural Evolution for High-Temperature Coated Particle Fuels |
| Author(s) |
Bryan M. Conry, Katherine Montoya, J. Wesley Jones, Ryan S. Heldt, Tyler J. Gerczak, Eddie Lopez-Honorato |
| On-Site Speaker (Planned) |
Katherine Montoya |
| Abstract Scope |
Tristructural isotropic (TRISO)–coated fuel particles have been developed as a robust nuclear fuel for use in high-temperature gas reactors (HTGRs). The TRISO architecture comprises a uranium-bearing kernel surrounded by multiple layers of pyrolytic carbon and a silicon carbide (SiC) layer; the SiC is the primary coating layer for limiting the release of fission products (FPs) not retained in the fuel kernel. The SiC microstructure (i.e., grain shape/size and grain boundary character) is known to contribute to the transport pathways facilitating this FP release. However, SiC experiences phase instability at temperatures beyond 1,800⁰C. Therefore, for high-temperature applications like space nuclear propulsion where operating temperatures exceed 2,000 ⁰C, zirconium carbide (ZrC) has been proposed as a high-temperature alternative. For deployment of this modified architecture, it is essential to understand their properties and behavior in these extreme environments. In particular, understanding how the coating microstructure evolves under these conditions is needed to predict the protective performance of the ZrC coating during high-temperature operation. Here, the microstructural evolution of two ZrC coatings with different stoichiometries was characterized after heat treatment at 1,900⁰C. Scanning electron microscopy and electron backscatter diffraction were used to characterize changes in the grain structure as a function of heat treatment time, as well as the grain boundary character, showing rapid initial grain growth and significant long-term difference as a function of Zr/C stoichiometry. These insights into ZrC microstructural stability under extreme thermal load will inform the design of next‐generation coated particle fuels with improved fission‐product retention and long‐term performance. |
| Proceedings Inclusion? |
Undecided |