Development and validation of the multi-physics DRACCAR code

To meet the simulation needs of its LOCA R&D program, the IRSN is developing a multi-rod computational tool named DRACCAR. In order to realistically describe the behavior of the reactor core during a Loss Of Coolant Accident (LOCA), modeling has to take into account many coupled phenomena such as thermics (heat generation, radiation, convection and conduction), hydraulics (multi dimensional 1-3 phase flow, shrinkage), mechanics (thermal dilatation, creep, embrittlement) and chemistry (oxidation, oxygen diffusion, hydriding,...). This paper presents several aspects of the DRACCAR code abilities: first to handle thermal-hydraulics during reflooding of an intact and of a partially ballooned bundle and secondly the simulation of the OECD SFP phase II experiment dealing with the instantaneous draining of a spent fuel pool.