September 25, 2026
Ontario Power Generation (OPG) is advancing the Pickering Nuclear Generating Station refurbishment, a major infrastructure program that will refurbish Units 5 through 8 and extend their operating lives for decades.
Preparatory construction and training activities are underway at the Pickering site, while the main reactor refurbishment execution phase remains subject to authorization from the Canadian Nuclear Safety Commission (CNSC). The CNSC is considering OPG’s refurbishment and licence applications through a two-part public hearing, with the second portion scheduled for October 6–9, 2026. OPG’s current project schedule anticipates the execution phase beginning in January 2027, pending regulatory approval.
The project will refurbish Pickering B’s four CANDU reactors—Units 5 through 8. OPG plans to replace 1,520 fuel channels and 48 boilers, along with other major station components and systems.
OPG says the refurbishment is intended to secure more than 2,000 MW of generating capacity for at least another 30 years. Units 5 through 8 are scheduled to be taken offline in September 2026 and prepared for refurbishment, with the refurbished units expected to return progressively to commercial service during the 2030s.
The Ontario government says major contracts have already been awarded for the project, including approximately $1.7 billion to Aecon Group and Candu Energy, an AtkinsRĂ©alis company, for execution of the Unit 5 Retube, Feeder and Boiler Replacement work.
Another $1.3-billion contract involving Aecon and Siemens Energy Canada covers turbine-generator replacement work, including steam turbine rotors, generator overhauls, stator rewinds and new auxiliary and control systems.
The province estimates that more than 90 per cent of project spending will remain within Ontario and Canada and projects significant employment and economic activity from the refurbishment. These figures are government estimates and will depend on project execution and broader economic conditions.
Preparing enough qualified workers is a major component of the refurbishment strategy.
A new 200,000-square-foot Retube, Feeder and Boiler Replacement Training and Mock-up facility is under construction at Pickering. The facility will provide workers with hands-on experience using detailed mock-ups of the reactor and its components before entering the reactor building.
The Ontario government says more than 2,800 skilled trades workers will receive training through the facility ahead of refurbishment activities.
The approach builds on experience gained during OPG’s Darlington Nuclear Generating Station refurbishment, where extensive worker training and mock-up facilities were used before crews performed complex reactor work.
OPG’s Pickering project is intended to extend the operating life of the four reactors while maintaining a major source of Ontario electricity.
The project also illustrates the construction complexity involved in extending the life of existing nuclear infrastructure. Refurbishment requires coordinated work across engineering, heavy construction, mechanical and electrical systems, skilled trades, manufacturing, component replacement, commissioning and regulatory oversight.
OPG reported in its 2025 financial disclosures that the approved budget for refurbishing the four units, including interest, escalation and contingency, is $26.8 billion. The company expects Unit 5 to be the first refurbished unit returned to service, currently targeted for 2031, with the overall refurbishment anticipated to be completed by 2034.
Although construction and preparation activities are progressing, the CNSC remains responsible for the independent regulatory decision on OPG’s application to refurbish Units 5 through 8 and renew the relevant operating licences.
The Commission’s second hearing phase is scheduled for October 2026 and will include submissions from OPG, CNSC staff, Indigenous Nations and communities, members of the public and other interested parties. A record of decision will be published after the Commission reaches its decision.
For Canada’s construction industry, the Pickering project represents a long-duration infrastructure program requiring extensive engineering expertise, specialized contractors, skilled trades and Canadian nuclear supply-chain capacity as OPG prepares for refurbishment work extending well into the next decade.
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