Bruce Power reconnects refurbished Candu reactor unit 3 to Ontario grid

Bruce Power synced refurbished Unit 3 to Ontario’s electricity grid at 1:34 a.m. on June 4, putting another Candu reactor back into service after a major overhaul that began in March 2023 and reached construction completion on February 18, 2026. The Canadian Nuclear Safety Commission removed the final regulatory hold point for the unit on June 2, clearing the way for the restart sequence.

The reactor is not back in routine commercial operation yet. Bruce Power said Unit 3 will continue power ascension and still has remaining testing and approvals to finish before it is cleared for full service. That distinction matters in nuclear work: a unit can be synchronized to the grid and still need weeks of checks, inspections, and commissioning before operators let it climb through higher power levels.

Bruce Power said fuel loading for Unit 3 began in February 2026, with operations staff refuelling 480 fuel channels with 5,760 fuel bundles over the coming weeks. The company said the unit’s major component replacement remains on budget and ahead of schedule. That gives Bruce another clean data point for a refurbishment model Canada is increasingly leaning on, where keeping large reactors running can be faster and cheaper than waiting on new build capacity to replace them.

Unit 3 is the latest test case in Bruce’s six-unit refurbishment program, which the company says began with Unit 6 in January 2020 and then Unit 3 in March 2023. Unit 6 returned to service in 2023, giving Bruce a working template for the current sequence. Unit 4 entered its major component replacement outage in February 2025 and sits at the midpoint of the project, while Units 1 and 2 were refurbished earlier and returned to service in 2012.

Each refurbished unit is expected to add about 30 to 35 years of operating life. Bruce Power says the full six-unit program is intended to extend the Bruce site’s operational life to 2064, a long runway for one of North America’s most important nuclear stations. The company and industry groups have also tied the life-extension effort to roughly 22,000 jobs annually and about C$4 billion a year in Ontario economic activity, while Bruce says its broader operations and life-extension program sustain about 27,000 direct and indirect jobs and keep 95% of spending in Canada.

Ontario’s Independent Electricity System Operator has projected electricity demand could rise by as much as 75% by 2050, which is why every successful Bruce restart lands as more than a technical milestone. It is another argument, backed by a synchronized unit at 1:34 a.m., that the province’s cheapest clean capacity may be the reactors it already has.