The IRIS integral reactor is on the path towards licensing. The paper deals with the study, design and set up of the experimental facility for the performance of the Integral Effect Tests (IET). IRIS owns specific layout, i.e. the integral configuration, and enhanced safety features, obtained also by exploiting a coupled dynamic behaviour during the accident sequences among the primary vessel and its components, the steel spherical containment and the passive safety systems. These design choices, very positive for the safety point of view, however require that the scaled simulator of the reactor must be able to simulate the dynamic behaviour of all the systems, containment included. The PIRT (Phenomena Identification and Ranking Table) analysis and the H2TS (Hierarchical, Two-Tired Scaling Analysis) process were adopted, leading to a 1:1 scaling in height, 1:100 in volume and power and with the fluid in prototypical conditions. A brief description of the facility is reported and a preliminary Text Matrix is presented as well.