Construction starts on small modular reactor at Darlington Nuclear site

Ontario Construction News staff writer

Ontario Power Generation (OPG) has broken ground on the first of four small modular reactors (SMRs) at the Darlington nuclear site, marking a significant milestone in Canada’s clean energy transition and setting the stage for the first operational SMR in the G7.

Once complete, the first reactor — a GE Hitachi BWRX-300 — will produce enough reliable, carbon-free electricity to power approximately 300,000 homes. The Darlington New Nuclear Project will eventually include four units, generating a combined 1,200 megawatts (MW) — enough to power 1.2 million homes — and help address the province’s growing electricity needs in the coming decades.

“This is a historic day for Canada as we start construction on the first small modular reactor in the G7, creating 18,000 jobs for Canadians,” said Stephen Lecce, Ontario’s Minister of Energy and Mines. “This nation-building project being built right here in Ontario will be led by Canadian workers using Canadian steel, concrete and materials to help deliver the extraordinary amount of reliable and clean power we will need to deliver on our ambitious plan to protect Ontario and unleash our economy.”

The construction contract for the first unit was awarded to Aecon Kiewit Nuclear Partners (AKNP), a general partnership between Aecon and Kiewit Nuclear Canada. The CAD $1.3 billion agreement covers project management, construction planning, and execution through to commercial operation, expected by the end of this decade.

In addition, Candu Energy Inc., a subsidiary of AtkinsRéalis (formerly SNC-Lavalin), was awarded a CAD $450 million contract to support the engineering, procurement, commissioning, and project management of the nuclear island and balance-of-plant for the first reactor.

The Ontario government projects that the construction of the four SMRs will inject an average of $500 million annually into the provincial economy, contributing $38.5 billion to Canada’s GDP over the project’s 65-year lifespan. Roughly 80 per cent of project spending is expected to flow to Ontario-based companies, sustaining an estimated 3,700 high-skilled jobs over the long term.

The BWRX-300 is a next-generation reactor design that uses commercially available uranium and established nuclear technology in a smaller, more flexible configuration. It is part of a broader strategy to replace aging baseload capacity and meet rising energy demand with non-emitting sources.

Ontario’s Independent Electricity System Operator (IESO) has endorsed the Darlington SMRs as the most cost-effective and lowest-risk option among available non-emitting technologies. The government’s decision also reflects confidence in OPG’s recent track record, including the successful refurbishment of the Darlington Nuclear Generating Station.

More than 80 Ontario-based suppliers have already signed agreements with OPG to support the project, laying the groundwork for Ontario’s leadership in the emerging global SMR market. Additional job-creating agreements with reactor vendor GE Hitachi are expected to be announced soon.

The project is also part of a national effort to develop SMRs across Canada, with OPG collaborating with utilities in Alberta, Saskatchewan and New Brunswick.

The Darlington SMRs form a key pillar of Ontario’s “Affordable Energy Future” plan, aimed at ensuring energy affordability and reliability as the province’s population and economy continue to grow.