Computational fluid dynamics simulation of gas-solid flow behavior in mini spouted bed reactor for TRISO fuel particle coating process

Indonesia has set a target of achieving net-zero emissions (NZE) by 2060, with nuclear power projected to play a significant role, including the deployment of High Temperature Gas-cooled Reactors (HTGR) using TRISO-coated fuel particles. A critical challenge in TRISO fuel fabrication lies in achieving uniform particle coating, which strongly depends on the hydrodynamics within spouted bed reactors. In this study, a three-dimensional Euler–Euler computational fluid dynamics (CFD) model was adopted to investigate gas–solid flow behavior in a mini spouted bed chemical vapor deposition reactor, where zirconia kernels were used as surrogate materials. The simulations examined the effects of key design and operating parameters, including gas inlet velocity (7–16 m/s), inlet diameter (3, 5, and 7 mm), static bed height, and bed angle (30°, 60°, 90°, 120°) as well as a hemispherical bottom inspired by previous reactor designs. The results showed that stable spouting was achieved at optimal inlet velocities of 13 m/s, with the smallest inlet diameter (3 mm) providing the best gas–solid contact efficiency. An intermediate static bed height was found to balance spouting stability and particle circulation, while the hemispherical bottom design yielded superior hydrodynamics compared to conical beds, due to smoother gas redistribution and reduced dead zones These results provide valuable insights for optimizing TRISO particle coating processes, and future work should focus on experimental validation and scale-up studies to further confirm these findings.