CANDU Vacuum Building

Vacuum Building

The Vacuum Building System is used in the CANDU plant design. Typically, a single Vacuum Building is used for each site. Bruce 1-4, Bruce 5-8, Pickering 1-8, Point Lepreau, and Gentilly have 1.

Model of Vacuum Building	Eight Pickering units with Vacuum Building at left

Photos by J.A. Gonyeau

In the photo on the left, the model shows the structure within the Vacuum Building. This building is maintained at a vacuum relative to the pressure in any of the reactor containments. If a large release of radioactive steam occurs in any of the containments, valves open to direct the high pressure steam to the vacuum building which includes a spray system to reduce the pressure both within the affected reactor containment and the vacuum building. Cool water sprays from sprinkler type units in the upper parts of the building to condense the steam.

The photo on the right shows the Vacuum Building as seen from the outside by the Pickering units.