Modeling of the space-dependentdynamics of FLUBER has been performed. The model consists of coupled neutronics, heat transfer as well asfluid dynamics/fluidization. A computational scheme for the neutronics comprises a second order even-parityfinite element method for solving the Boltzman transport equation, while for the the fluid dynamics a nonlinearPetrov-Galerkin method is used for discretizing the momentum equation of the two-fluid model (or Eulerian-Eulerian model). The solid phase rheology is described with the kinetic theory of granular flows to obtainclosure equations for the solid phase viscosity and pressure as a function of the random fluctuating particlevelocity. Simulation to the dynamics of the reactor has been performed for an uranium inventory of 120 kg andcoolant inlet velocities of 120 cm/s and 180 cm/s. The results shows that the fission power is highly fluctuativebut the mean gas temperature is modest. The magnitude of the generated fission power depends on the flow rateof fluidizing gas. When the gas flow rate is high enough so that the bed height lies in the overmoderated region,the fission power is maintained only by neutron sources.Keywords: Space-dependent dynamics, Fluidized Bed Nuclear Reactor, even-parity transport equation, finiteelement methods. Alexander AgungNuclear Engineering Program, Department of Engineering PhysicsUniversitas Gadjah Mada, Yogyakarta, Indonesia, E-mail: a_agung@ugm.ac.id
