ABSTRACT
Containment thermal hydraulics concerns itself with the flows of heat and matter into and from the containment atmosphere, and with the circulation of the gases within the containment. Containment fission product transport studies the behaviour of fission product vapours and aerosols within the containment atmosphere. The role of thermal hydraulics has been seen as assessing the threat to the containment structure, while that of fission product transport has been seen as calculating the radiological source term to the environment. In traditional containment thermal hydraulic codes a distinction is made between the condensation on the walls and the condensation in the bulk. The condensation of vapour onto aerosols induces a particularly tight coupling between aerosol behaviour and thermal hydraulics, and it involves problems both of detailed physical modelling and of the incorporation of the models within a computer code. Of all the coupling phenomena, it is the condensation of vapours in the bulk atmosphere which has attracted the most attention.
