Application of Meshless Pore-Level Model to Pyrolysis and Synthesis of Nuclear Fuels

Uranium-ceramic nuclear fuels can be fabricated through pyrolysis-based materials processing technique. This technique requires lower energy compared to sintering route. During the fabrication process, the source material changes composition continuously and chemical reactions and transport phenomena vary accordingly. Therefore, to obtain such nuclear fuel materials with high uniformity of microstructure/species without crack, transport phenomena in the material processing needs to be better understood. A system-scale model has been developed to account for the pyrolysis-based uranium-ceramic nuclear material processing in our prior work. In this study, a pore-scale numerical model based on Smoothed Particle Hydrodynamics (SPH) will be described for modeling the synthesis of SiC matrix and U₃O₈. The system-level model provides thermal boundary conditions to the pore-level model. The microstructure and compositions of the produced composites will be studied. Since the control of process temperature plays an important role in the material quality, the effects of heating rate and U₃O₈ particle size and volume on species uniformity and microstructure are investigated.