A 3D MULTI-PHYSICS MODELLING OF THE TRIGA MARK II REACTOR

The TRIGA Mark II reactor of the University of Pavia is a research reactor that can be operatedup to 250 kW in steady state. It reached its first criticality in 1965 and thereafter was used for many scientific and technical applications. In the last years, different simulations tools were developed for a complete and accurate characterization of the reactor, analyzing in detail neutronics, burnup and thermal-hydraulics. They were studied separately, without considering the mutual interaction of the different physics phenomena in a same simulation environment. For this reason, a three dimensional Multi-Physics Modelling (MPM) approach is developed in this paper, by using Comsol Multi-Physics. In neutronics, a time dependent multi-group diffusion solver is implemented. The neutronics solver is verified by a code-to-code comparision with a Serpent Monte Carlo model, that is used for cross sections at criticality conditions of different power levels. In thermal-hydraulics, Reynolds Averaged Navier-Stokes (RANS) equations with k−ω turbulence model are employed for fluid dynamics. After these verifications, the coupling is implemented by changing the power generation term and by obtaining a databaseof cross sections at different temperature.