Numerical Simulations of Particle Motion in a Two-Dimensional Pebble Bed Modular Reactor

Motions of fuel and graphite pebbles in a two-dimensional pebble bed modular reactor（PBMR） have been numerically simulated by means of particle discrete element method（PDEM）.Velocity profiles,mixing and effect of frictional coefficient of pebbles and wall on flow behavior of particles was investigated.Results indicated that both fuel pebbles and graphite pebbles move down without radial movement,and uniform motion was formed in the column regime.While particles will be accelerated,some particles will attach to the walls at the taped part of reactor due to the reduction of sectional-area.The different residence time of fuel and graphite pebbles was found.The residence time of graphite pebbles is shorter than that of fuel pebbles.With the decrease of friction coefficient of pebbles and walls,the residence time of sphere particles were increased.