Powder fluidization dynamics in uranium dioxide production

The fluidization bed technique is a widely used method to produce U O2 powder from chemical conversion of AUC (Ammonium Uranyl Carbonate). The process consists in a countercurrent particle-gas flow, where the powder falls by sedimentation against a superheated water steam upflow. The uranium compounds undergoes a series of chemical reactions until it reaches the U O2 state. In this paper a study of the fluid dynamic features of the sedimentation-reaction process is presented. The particle-gas flow is mathematically described with a two-phase drift-flux model modified to simulate changes in the particle properties during the reaction. (author)