JERICHO, a code for computation of containment thermal-hydraulic behaviour during a severe accident in a NPP

The JERICHO code has been developed in the context of the ESCADRE system in order to analyse the evolution of thermal-hydraulic conditions in the containment over a period of several days in the event of a severe accident. These conditions are assessed by dividing the available energy between the containment atmosphere, the sump water volume and the walls. The containment can be divided into several compartments describing the gas atmosphere, the sump water and the structures. The subcompartments are assumed to be homogeneous, pressure and temperature balanced. The containment atmosphere can consist of oxygen, nitrogen, steam, hydrogen, carbon monoxide and carbon dioxide. The application of the code allows computation of the thermal-hydraulic behaviour of the containment of a nuclear power plant for a large range of severe accidents scenarios including the use of the main accident mitigation procedures. (orig./DG)