Numerical study of uranium hexafluoride desublimation process based on Eulerian two-phase model

Abstract

This paper presents a numerical study on the condensation process of uranium hexafluoride (UF6) in the supply and extraction system of a uranium enrichment plant. The numerical study was conducted using a standard UF6 receiving container with a nominal diameter of 127 mm and a volume of 8L under constant temperature boundary conditions. A phase change heat and mass transfer model for the desublimation process of uranium hexafluoride gas was established, and this model was combined with the Euler two fluid model to predict the distribution of key parameters such as temperature, pressure, and volume fraction of each phase during the UF6 cooling process, as well as the gas flow characteristics inside the container. In addition, this study also investigated the influence of various factors on the cooling rate. The research results indicated that UF6 gas initially condensed on the container wall and gradually diffused inward, with the highest solid density observed on the wall. Furthermore, increasing the inlet gas temperature, inlet mass flow rate, and reducing the cooling temperature, initial pressure inside the container could all enhance the desublimation rate to various degrees. The optimization plan proposed based on the above influencing factors could increase the yield of UF6 solid by 64.20% in 2 h, compared to the basic operating conditions.