Plateau facility in support to ASTRID and the SFR program : an overview of the first mock-up of the ASTRID upper plenum , MICAS

International audience; The CEA and several industrial partners are involved in the development of a 4th generation reactor cooled by sodium. This sodium fast neutron reactor called ASTRID (Advanced Sodium Technological Reactor for Industrial Demonstration) is a 600 MWe. It is a pool reactor type and integers cutting edge technologies.Developments are in progress especially for the vessel and the apparatus. Experiments are needed for both validation of numerical codes and specific studies. In this way, a thermal-hydraulic loop, the PLATEAU facility, has been developed and built at the CEA Cadarache. Different mock-ups can be connected to this loop to study the different issues at various reactor conditions. Currently, 4 mock-ups have been identified: the internal vessel, the entire pool reactor, the link between the external and the internal vessel, a part of the internal vessel at a higher scale to study specific issues.The MICAS mock-up is dedicated to study the flow regime of the internal vessel (hot plenum), both for code validation and also engineering design development.It has been designed at a reduced scale and integers as hydraulic obstacles all the apparatus immersed in the internal vessel. This mock-up has been built in transparent polymer to carry out some optical measurements as laser velocimetry. Numerical studies with StarCCM+ has been engaged to determine the general flow pattern in a way to identify the area of interest for detailed phenomenological studies in order to define optimised instrumentation mapping.This article is dedicated to present PLATEAU facility and the experimental program on the MICAS mock-up. In the first part, the ASTRID reactor concept is briefly presented. Then the PLATEAU experimental facility is descripted in detail. The issues of the internal vessel are summed-up and the MICAS mock-up is presented. Then some numerical calculation results are showed to illustrate the flow in the internal vessel.