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

That report has been issued in the frame of the second research programme of ENEA-MSE agreement and it is one of the deliverables of the task F 'CFD analyses of the dowcomer in support of the design' of the work-programme 2 'Evolutionary INTD reactors' of the research theme on 'Nuovo Nucleare da Fissione'. The reports deals with the design of an experimental facility planned to provide data relevant for the mixing phenomena in the downcomer and lower plenum of the IRIS reactor when a DVI line break accident (SBLOCA) occurs and for CFD codes validation. The thermal-hydraulic behaviour of the facility has been simulated by using the FLUENT code. The boundary conditions related to the postulated accident scenarios to be used in the CFD calculations were drawn from previous information coming from system code simulations.