Ontario Power Generation (OPG) announced on March 27 that construction is complete on Darlington Nuclear Generating Station’s Unit 2 reactor.

The unit will now begin the restart process before being connected to the electricity grid, subject to regulatory approvals from the Canadian Nuclear Safety Commission—and OPG’s ability to do so safely given the current COVID-19 crisis.

“On behalf of all OPG employees, project partners and vendors, I want to thank our refurbishment team on completing the final steps of construction on Unit 2 under unprecedented and extraordinary circumstances,” said Ken Hartwick, OPG’s President and CEO. “The project team continued to work safely and diligently while managing changes required as a result of the COVID-19 pandemic.”

Construction work on the reactor began more than three years ago. The project is part of a four-unit rehabilitation at the facility which is scheduled for completion in 2026, and will extend the life of the station by an additional 30 years. Construction was performed by a joint venture between Aecon Group and SNC-Lavalin Nuclear, and was valued at $2.75 billion.

Reconnecting the reactor may prove to be a challenge, given the COVID-19 pandemic. During the last stages of construction, the project team adopted stringent health and safety measures to ensure worker health and safety.

For the time being, OPG has said it will continue operating the Darlington Nuclear Generating Station’s Unit 3 reactor. This change has the knock-on effect of delaying the planned start of the Unit 3 refurbishment, which was scheduled to begin in May.

"In the coming weeks, the Darlington Unit 3 project team will determine the best time to restart the project, ensuring the required critical resources and materials are available,” said OPG. “Critical initiatives, such as completion of Darlington Unit 2's refurbishment and preparations for the spring continue as planned."

Refurbishment of Darlington 1 is scheduled to begin in 2021; work on Unit 4 is scheduled to begin in 2023.

In addition to providing almost half of Ontario’s electricity, OPG also supplies one of the most valuable medical isotopes, Cobalt-60. Currently, almost half of the world’s Cobalt-60 is supplied by Ontario’s nuclear reactors to irradiate and sterilize about 40 percent of the world’s single-use medical devices such as syringes, gloves, implants and surgical instruments.