Particles growth by steam nucleation in a containment. The PITEAS experiment

One of the major issues of the fission products inventory in the containment of a nuclear power plant during the few hours following the initiating phase of a severe accident (involving core degradation and fission products release from the fuel) is the physical behaviour of the aerosols suspended in the containment atmosphere. The aerosol mass concentration versus time is controlled by agglomeration, sedimentation, deposition on walls and steam nucleation phenomena. In order to assess the Nuclear Safety codes dealing with such phenomena, analytical experiments are necessary. PITEAS is an analytical experiment, on the behaviour of soluble aerosols in humid atmosphere. The PITEAS program covers three topics: diffusiophoresis, agglomeration and particle growth by steam nucleation. In the present work, we analyse the results of the tests devoted to the soluble particle growth and how such results are used to assess the IPSN code AEROSOL-B2 code, part of the System of codes ESCADRE. (author)