CFD analysis of the flow in the MICAS experimental facility, a water model of the hot pool of a sodium cooled fast reactor

Abstract Sodium Cooled Fast Reactors (SFRs) have been developed in France for about 50 years including the research reactors Rapsodie and Phenix as well as the Superphenix plant. In the framework of Generation IV reactor deployment, the development the Advanced Sodium Technological Reactor for Industrial Demonstration (ASTRID) was started in 2006 under the leadership of CEA. Current activities on the use of Computational Fluid Dynamics (CFD) in the ASTRID project are focused on the validation of computational tools to predict the thermal–hydraulic behavior of sodium in the reactor vessel. As thermal hydraulics is recognized as key scientific subject in the development of SFRs, new experiments are realized for both qualification of design options and validation of code calculations. Large scale tests are conducted in water models such as the MICAS facility, which represents the hot pool of the ASTRID reactor in 1/6 scale including all internals. The facility is built in transparent polymer for accurate optical measurements of the flow field under various flow conditions. The flow in the MICAS facility is analyzed with the CEA in-house code TrioCFD, the reference CFD code of the Nuclear Reactor Division of the CEA. The use of HPC (High Performance Computing) allows the access to flow fields in complex geometrical structures with a high resolution in time and space. The validation of the modelling approach is shown on the example of the MICAS experiment by comparing calculation results (velocity fields) to LDV measurements. Detailed information is given on the test facility, the used modelling approach and the comparison between experiment and calculation. Although the calculation is globally in accordance to the experiment, differences exist locally due to the complexity of the flow topology in the hot pool.