Canada’s Bruce Power’s Bruce A generating station closed all four operating units (1-4) on 9 May for its planned vacuum building outage (VBO).
Vacuum buildings are unique to multi-unit Candu generating stations and are part of their robust safety systems, providing an additional protective barrier to the release of radioactivity to the environment. All four operating units must be shut down once every 12 years to allow for inspections and maintenance to the vacuum building.
During the VBO, Bruce Power is investing in an innovative new filtration system which will provide an extra layer of safety and protection. The new system is expected to be fully commissioned and available by the end of 2022.
“With four operating units out of service, this is not a typical outage campaign,” said Frank Payne, Vice President of Bruce A. “Years of planning and preparation goes into our VBO outages and we are ready to safely carry out our maintenance and inspection work and successfully return these units to service.”
Bruce Power works closely with the Independent Electricity System Operator (IESO) to ensure the timing of these outages can be accommodated to meet the needs of the province’s electricity grid. VBOs are scheduled during periods of the year when demand is expected to be low – usually the spring or fall. This allows Bruce Power to make sure its units will be operational for the summer peak period, providing about 30 per cent of Ontario’s electricity with zero carbon emissions at a time when reliable energy is most needed.
Before it was closed, unit 2 achieved a record run of 626 consecutive days. This eclipsed its previous post-restart record of 282 days during this run that began in August 2020. This milestone comes in the reactor’s 45th year since being put into service in 1977 and is significant as it demonstrates the value of refurbishing Ontario’s nuclear fleet, as the unit was restarted in 2012 after being laid up in 1995 by the former Ontario Hydro.
Bruce A was one of the top performing nuclear plants in the world in the early-1980s. In 2007, unit 2 made history with the first successful replacement of a steam generator in a Canadian nuclear plant. In 2012, a refurbished unit 2 was returned to service, 17 years after being mothballed. Unit 2’s gross peak capability will be raised by 39 MWe to 880 MWe, following this outage, based on system improvements made during the original unit 2 restart and subsequent maintenance outages
This work is part of Bruce Power’s Project 2030, which will see the company invest in innovative upgrades to raise its eight-unit maximum capacity to 7,000 MWe by 2030. The Bruce Power site currently has an eight-unit capability of 6,550 MWe - Bruce A (units 1-4) and Bruce B (units 5-8).
Photo: Bruce nuclear power plant (credit: Bruce Power)