After nearly four years of work, the Darlington Nuclear Generating Station's Unit 2 reactor has been reconnected to Ontario's electricity grid.

Ontario Power Generation (OPG) made the announcement on June 4.

"This is a truly historic moment for Ontario. I want to thank our refurbishment team, project partners, vendors and construction building trades workers for more than 24 million hours worked safely and for returning Darlington's Unit 2 reactor to the grid at a time of unprecedented circumstances," said OPG president and CEO Ken Hartwick.

The refurbishment of Unit 2 is the first of a four-phase project at the Darlington station—worth more than $13 billion. The project was led by a consortium that included SNC-Lavalin with involvement from such firms as Aecon and Black and McDonald.

Over the construction period, which began in 2016, more than 2,300 workers logged more than eight million hours of work. The teams replaced 480 fuel channels, installed more than 27 kilometres of pipe, made nearly 4,000 radiographic welds, and installed more than 300,000 fasteners, nuts, bolts, screws and washers.

“Congratulations to Ontario Power Generation and all your employees on the hard work that contributed to this important milestone that is the return to service of Darlington’s Unit 2,” said Sandy Taylor, President, Nuclear, SNC-Lavalin. “Thousands of individuals and hundreds of vendors came together to collaborate and brought their best, showcasing Ontario’s nuclear advantage. The best practices and application of new tools will be a legacy for other life extensions to come.” 

The next stage of the project, work on the Unit 3 refurbishment, was due to begin last month. That work was postponed due to the COVID-19 pandemic, however. OPG hopes to begin prerequisite activities on this project phase later this month. That phase is expected to be completed in 2023, with work on units 1 and 4 scheduled for completion in 2024 and 2026.

The Darlington Refurbishment Project is one of Canada’s largest clean-energy projects. The 10-year undertaking will extend the lifetime of the four-unit station for at least another 30 years. In so doing, facility operations are estimated to remove the annual equivalent in greenhouse gas emissions of two million cars from Ontario’s roads.

The refurbishment project, which is expected to generate a total of nearly $90 billion in economic benefits for Ontario and increase employment by an average of 14,200 jobs annually across the province, also plays a significant role in Ontario's fight against climate change.

“A big thanks to SNC-Lavalin’s nuclear team and our CanAtom joint venture partner Aecon for completing and maintaining the high quality and standards for the retube and feeder replacement of 480 fuel channels,” said Bill Fox, Executive Vice-President, Nuclear at SNC-Lavalin. “The team worked diligently for three-and-a-half-years to safely execute the refurbishment activities on the unit ahead of the revised schedule.”