Containment System

The primary system, the reactor coolant pressure boundary, and important ancillary systems are enclosed in the primary containment, a cylindrical concrete structure with an embedded steel liner. The primary containment is of pressure-suppression type with two major compartments: a dry-well and wet-well. The dry-well includes the volume that surrounds the reactor pressure vessel and the second shutdown system rooms.

A partition floor and cylindrical wall separate the dry-well from the wet-well. The lower part of wet-well volume is filled with water that works as the condensation pool, and the upper part is a gas compression chamber.

In the event of LOCA, the dry-well will be pressurised with the steam and its atmosphere will be pushed into the condensation pool via tube vents. Non-condensable gases will be collected in the gas compression chamber whereas the steam will condense in the pool water. The pressure inside the containment is kept below the maximum design value of 5 bar, without any external action. The tube vents have been designed with horizontal discharge to reduce the dynamic load on the containment structure.