The Bruce site, 18 kilometres north of the town of Kincardine in Bruce County, is home to eight operating Candu units: units 1-4 are known together as Bruce A and units 5-8 as Bruce B.
Major Component Replacement – or MCR – involves removing and replacing key reactor components including steam generators, pressure tubes, calandria tubes and feeder tubes and adding 30-35 years to the reactor’s operating life. Units 1 and 2 have already been refurbished, returning to operations in 2012. The process has already been completed at Bruce 6, which returned to commercial service in September 2023. Unit 3 was taken offline to begin its MCR outage in March 2023, while the refurbishment of Unit 4 began in February 2025. Units 5, 7 and 8 are also to be refurbished, with units in overlapping MCR outages until 2033. Ontario’s Independent Electricity System Operator (IESO) will also study the possibility of a second refurbishment of units 1 and 2 in the future.
The construction phase of the Unit 3 MCR, completed with execution partner Shoreline Power Group (SPG) – a joint venture between Aecon, AtkinsRéalis and United Engineers and Constructors – included the removal and replacement of 480 fuel channels and 960 end fittings, as well as eight steam generators. Steam generator work was completed by Steam Generator Replacement Team (SGRT), a 50/50 joint venture between Aecon and SGT (a partnership between Framatome Canada Ltd and United Canadian Operations Ltd).
“Completing the construction phase of Unit 3’s Major Component Replacement is a major step forward for Ontario’s clean energy future,” said Eric Chassard, Bruce Power’s President and Chief Executive Officer. “Thanks to the safe, high-quality and disciplined work of our people, skilled trades and partners – and the innovative tooling that’s delivering step improvements in nuclear refurbishment performance – we’re now focused on returning this renewed unit to service on budget and ahead of schedule.”
“Delivering strong performance on a project of this scale is the result of relentless focus on safety, disciplined execution, and the ability to innovate,” said Laurent Seigle, Bruce Power’s Executive Vice-President, Projects. “By applying lessons learned, investing in new tooling, and working as one team with our partners and skilled trades, we continue to raise the bar with each Major Component Replacement, improving schedule certainty, quality, and efficiency while setting the foundation for the units that follow.”
With the Unit 3 refurbishment complete, the Canadian Nuclear Safety Commission (CNSC) has now approved Bruce Power’s request to remove the first regulatory hold point (RHP-1), allowing fuel to be loaded in the Unit 3 reactor, following the Major Component Replacement outage. “Bruce Power has met all of the pre-requisites established by the CNSC to remove RHP-1,” the regulator said in a 16 February letter to Bruce Power.
“Now, the focus shifts to returning the renewed unit to service in the coming months,” Bruce Power said. “Bruce Power Operations staff will begin refuelling the unit with 5,760 fuel bundles later this month, while other lead-out activities and regulatory inspections will be completed to return it to Ontario’s electricity grid.”
“Unit 3’s Major Component Replacement is another powerful example of Ontario’s nuclear advantage in action,” said Stephen Lecce, Minister of Energy and Mines. “Ontario’s skilled trades and nuclear workforce delivered this milestone, strengthening our energy self-reliance. This investment powers 22,000 jobs, adds CAD4 billion (USD3 billion) to our economy, and ensures clean, reliable electricity for decades – a made-in-Canada success story driving Ontario’s future.”
Bruce Power said its MCR and Asset Management investments are closely co-ordinated with Project 2030, a programme that leverages innovation and new efficient technology to increase site capacity, targeting upwards of 7,000 MW net peak output in the early-2030s, once all units have completed their MCRs.
