I-7. The ice condenser containment (Fig. I-3) system in pressurized water reactors uses a concept for the pressure suppression system in which the high pressure steam-air mixture resulting from an accident conditions pipe rupture is directed through vent doors into chambers containing baskets filled with ice. The steam condenses onto the surface of the ice in the baskets.

I-8. The containment is formed by a cylindrical structure divided into three isolated compartments: the lower area, which contains all the major components of the reactor coolant system, the ice condenser chambers and the main upper containment volume. Non-condensable gases (including noble gas fission products), which are forced into the ice condenser chambers, are vented through doors into the main upper containment volume.

I-9. An active spray system is used in the lower containment volume to reduce pressures and temperatures and to remove airborne radioiodine from the containment volume. The initial source of water for this system is a water storage tank.

I-10. After exhaustion of this water supply, a recirculation mode is initiated wherein the water is pumped from the building sump through a heat exchanger and then returned to the spray headers.

FIG. I-3. Schematic diagram of an ice condenser containment system for a pressurized water reactor; 1, containment; 2, upper containment volume; 3, ice condenser; 4, lower containment volume; 5, lower containment spray system; 6, filtered air discharge system; 7, liner.