Fluid dynamic simulation of the non homogeneous steam-air mixture motion in the dome of MARS safety core cooling system

One of the main features of the MARS, an inherently safe nuclear reactor of the new generation, is the innovative decay heat removal system. This has a high inherent reliability thanks to the complete absence of active components. The core decay heat is removed by the vaporization of the water in an emergency reservoir; then the steam collected in the dome over the pool condenses in the air condenser and returns back to the reservoir creating a heat sink of nearly infinite capacity. The transient fluid dynamic numerical simulation of the steam-air mixture flow in the dome is presented. This allows an assessment to be made of the time required for the uncondensable gases to be evacuated. After that time the condenser works at its rated capacity. (4 figures) (Author)