CFD analysis in support to the experimental activity on the mixing processes in the downcomer and lower plenum of IRIS reactor

................................................................................................................................... 2 1. FACILITY AND SCALING ANALYSIS.................................................................................. 4 1.1 Facility description................................................................................................................4 1.2 Scaling approaches................................................................................................................8 2. FLUENT simulations ................................................................................................................ 12 2.1 Geometrical domains for IRIS and for the facility..............................................................12 2.2 Operative and boundary conditions.....................................................................................17 3. OBTAINED RESULTS ............................................................................................................ 26 3.1 Mixing flows analysis in the IRIS downcomer and in the facility......................................26 3.2 The importance of the assumption made for the scaling analysis.......................................44 3.3 DVI length influence on the temperature field....................................................................53 CONCLUSIONS........................................................................................................................... 60