The Direct Containment Heating (DCH) issue, in Pressurized Water Reactor (PWR) plants having a direct path from the reactor cavity to the containment dome, has been investigated for low primary pressure (less than 20 bar). In the frame of a French-German collaboration between IRSN and FZK new experiments have been carried out using simulant materials and 3-dimensional high geometrically detailed mock-ups of the French P’4 plant at the linear scale 1/16. Two series of experiments have been carried out using two separate, but geometrically similar, experimental installations: 1) The “Cold” experiments focus on the corium entrainment and dispersion; 2) The “Hot” experiments give further insight of heat exchanges, and induced hydrogen combustion. Among the investigated conditions the case of an inert initial containment atmosphere has been considered and was funded by the EU Commission (LACOMERA project). Results of this test and of a series of “cold” tests are presented in the paper. Beside the experimental tests, a modeling work is being carried out using the multi-dimensional multi-phase computational fluid dynamic codes AFDM and MC3D. AFDM capabilities allow complete calculations, including combustion. Pre-tests analyses have been carried out in order to better define the tests conditions and to advance the credibility of AFDM results for future extrapolations to reactor conditions, and post-test analyses to contribute to the interpretation of the experimental results. MC3D is currently used in a different way, in order to investigate details of the fuel flow characteristics.