ALMR RVACS

RVACS stands for Reactor Vessel Auxillary Cooling System. Should the primary core cooling system malfunction or be unable to adequately cool the core and if radiative heat transfer is not sufficient, the RVACS can handle the core cooling to achieve a cold shutdown of the reactor.

The RVACS consists of an air-pathway which allows outside air to circulate around and cool the outside of the containment vessel with the hot air then exiting the pathway. The most visible parts of the RVACS are the air stacks that project above the ground through which the air enters and exits the cooling pathway. There are four RVACS stacks per reactor. The beauty of the system is that it can cool the reactor without using moving parts.

The main fear of the RVACS method of heat removal is that no cooling is possible if the airways become blocked. Tests conducted on models have shown that should 75% of the airducts become blocked, that the peak fuel temperature would still be below design specifications. Even if all airways are blocked, it would take twelve hours before the design specifications would be exceeded. Generally if the air can move, the RVACS can cool the core.