About this Abstract |
| Meeting |
Materials in Nuclear Energy Systems (MiNES) 2025
|
| Symposium
|
Materials in Nuclear Energy Systems (MiNES) 2025
|
| Presentation Title |
Multiscale, Mechanistic Modeling of Ag and Cs Fission Product Transport in TRISO |
| Author(s) |
Pierre-Clement A. Simon, Jia-Hong Ke, Chao Jiang, Larry Aagesen, Wen Jiang, Jacob Hirschhorn, Stephen Novascone |
| On-Site Speaker (Planned) |
Pierre-Clement A. Simon |
| Abstract Scope |
TRistructural ISOtropic (TRISO) fuel offers key fuel performance qualities that make it a robust, reliable, and attractive fuel option for advanced reactors. One of the main goals of a TRISO particle is to retain the fission products it produces. However, some release has been observed from intact particles. This presentation offers a multiscale, mechanistic model to elucidate the transport mechanisms of cesium (Cs) and silver (Ag) fission products in TRISO fuel particles, with an emphasis on microstructure effects and temperature-dependent diffusion regimes in the silicon carbide (SiC) layer – the main retention barrier. Our model integrates atomistic simulations and phase field modeling to quantify the impact of temperature and grain size on Cs and Ag diffusivity. We identify a transition from bulk-dominated diffusivity at high temperatures to grain boundary (GB)-dominated diffusivity at lower temperatures for Cs, and a significant dependence of both Cs and Ag diffusion on the size of SiC grains. Additionally, we account for irradiation-enhanced Ag diffusivity, expanding the model's accuracy across a broader range of advanced reactor conditions. The effective diffusion coefficients derived from our mesoscale approach are implemented in the fuel performance code BISON, improving its predictive capability for fission product release. Our model is validated against diffusion measurements and post-irradiation data from the Advanced Gas Reactor Fuel Development and Qualification Program (AGR-1 and AGR-2). This work advances the understanding of fission product transport in SiC, with significant implications for the safety and efficiency of high-temperature nuclear reactors. |
| Proceedings Inclusion? |
Undecided |