Ten-yearly overhaul begins at Bruce B vacuum building

The Vacuum Building Outage (VBO) which began on 24 April is the culmination of extensive planning, resourcing and co-ordination and is being carried out in cooperation with Ontario's Independent Electricity System Operator (IESO) and electricity transmission and distribution service provider Hydro One.

Vacuum buildings are unique to multi-unit Candu generating stations. Designed to quickly and safely lower pressure inside the reactor building in the case of an accident by releasing steam and hot gases from the reactor building into the vacuum building, the vacuum building provides an additional protective barrier to prevent the release of radioactivity to the environment.

"Bringing all of the station's operating units off-line at once is a large undertaking and our team has been planning for years to ensure it is completed safely," said Bruce B Vice President Adrian London. "The Vacuum Building Outage removes about 15 per cent of the capacity available to the Independent Electricity System Operator grid, so the people of Ontario are counting on us to bring our units back online successfully to continue to provide clean, reliable power."

Bruce Power said it works closely with the IESO to ensure the timing of the outages can be accommodated to meet the needs of the electricity grid. VBOs are scheduled during periods of the year when demand is expected to be low - usually in the spring or autumn.

Bruce A's vacuum building underwent a similar outage in 2022.