Large-Eddy simulation of the TRIGA Mark II Reactor Core

Complex industrial applications still handle turbulence modelling using Reynolds Averaged Navier Stokes (RANS) models. Based on local-averaged quantities, this approach reduces the required computational effort with respect to more accurate modelling strategies for turbulence, such as Large-Eddy Simulation (LES). Despite its limitations, RANS is still the most popular approach in use for CFD analysis in the nuclear field. However, in recent years the safety requirements for nuclear installations have become even more restrictive, and accurate fluid-dynamics simulation for safety-related purposes must take into account the impact that turbulence can have on the diffusion of momentum and energy and any local phenomena that may contribute to instabilities. RANS modelling cannot provide the required level of accuracy and rigour in the treatment of turbulence, and reactor modelling using LES approaches is an ongoing field of research. This work further explores this field by proposing a full LES analysis of the reactor core of the TRIGA Mark II reactor at the University of Pavia, also providing some best practices for LES simulations. Preliminary results of the proposed model are presented and compared with RANS ones previously obtained.