Thermal-hydraulic studies of a transmutation advanced device for sustainable energy applications

The Transmutation Advanced Device for Sustainable Energy Applications (TADSEA) is a pebble-bed Accelerator Driven System (ADS) with a graphite-gas configuration, designed for nuclear waste transmutation and obtaining heat at very high temperatures to produce hydrogen. In previous thermal-hydraulic studies of the TADSEA using a Computational Fluid Dynamics (CFD) code, the pebble-bed reactor core was considered as a porous medium. In this paper, the heat transfer from the fuel elements to the coolant was analysed for three core states during normal operation. The heat transfer inside the spherical fuel elements was also studied. Three critical fuel elements groups were defined regarding their position inside the core. Results were compared with a realistic CFD model of the critical fuel elements groups. During the steady state, no critical elements reached the limit temperature of this type of fuel. Two transients were also studied with reduced coolant mass flow and loss of forced reactor cooling without sh...