Pore flow analysis of sweep gas in tritium breeder pebble bed

Solid breeding blanket is an important type of breeding blanket for fusion reactor or fusion-fission hybrid reactor. It is helpful for the study of tritium sweeping and the optimization of solid breeding blanket structure when one has a good knowledge of the sweep gas pore flow in the pebble bed. In this paper, the packing and porosity distribution in the tritium breeder pebble bed are obtained with the discrete element code PFC3D, and three different sizes of control cells are obtained at randomly distributed positions. With the Boolean operation, the ball volume is subtracted from the cell to get the three-dimensional calculating domain of pore flow. And then this domain is meshed and a computational fluid dynamics (CFD) solver is used to solve the flow equations and get the velocity distribution and pressure drop per length. The results indicate that the velocity magnitude distribution obeys the Gamma distribution. CFD solver is proven to be a reliable tool for sweep gas pore flow when the control cell is properly chosen. This study is helpful for further research of tritium releasing and sweeping.