SIMULATION OF SEVERE ACCIDENTS WITH DETAILED THERMAL-HYDRAULIC MODELS

Thermal hydraulic phenomena play a decisive role for the course of sev ere accidents in light water reactors. Therefore, the simulation of th ese accidents with computer codes requires comprehensive and detailed modelling of these processes. The cone ATHLET-CD is being developed fo r realistic simulation of accidents with cole degradation and for eval uation of accident management measures. It makes use of the detailed a nd validated models of the thermal hydraulic code ATHLET in efficient coupling with models for core melting and fission product behavior The capabilities of the coupled code are demonstrated by a calculation of the TMI-2 accident.