The Ontario government has approved Ontario Power Generation’s (OPG) plan to begin construction on the first of four small modular reactors (SMRs) at the Darlington nuclear site.

Once complete, the SMR will be the first of its kind in the G7, producing enough reliable, affordable and clean electricity to power the equivalent of 300,000 homes.

Construction is expected to create as many as 18,000 jobs and inject $500 million on average annually into Ontario’s economy. The construction, operation and maintenance of the four units will add $38.5 billion to Canada’s GDP over the next 65 years.

The province says it has worked with OPG to ensure that 80 percent of project spending goes to Ontario companies and that construction and operations will protect Ontario workers and jobs by sustaining an estimated 3,700 highly-skilled, good-paying jobs for the next 65 years.

“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 Energy Minister Stephen Lecce. “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 BWRX-300 is a small-scale nuclear reactor that uses commercially available uranium to generate power. The four SMRs will be vital to powering new homes, historic investments to build Ontario and fuel a thriving economy. Once complete, they will produce 1,200 megawatts (MW) of electricity, enough to power the equivalent of 1.2 million homes, to help bridge a power gap that could emerge in the early 2030s in the absence of net-new baseload power sources added to the grid.

With energy demand expected to rise by 75% by 2050, Ontario’s Independent Electricity System Operator (IESO) concluded that the Darlington New Nuclear Project is the best option to meet growing demand in terms of costs and risks, when compared against non-emitting generation alternatives.

According to the IESO, the province would need to build up to 8,900 MW of wind and solar paired with battery storage to replace the output of four SMRs. The IESO also concluded this alternative approach would carry significant risks including significant land requirements and the need for large scale transmission build out.

This, combined with OPG’s outstanding track-record on the Darlington Refurbishment Project, factored into the government’s decision to support the Darlington New Nuclear Project.

The first SMR will cost $6.1 billion, along with costs for systems and services common to all four SMRs of $1.6 billion. Costs are expected to decline with each subsequent unit as efficiencies are gained, similar to the Darlington Refurbishment Project.

Construction work on the site will be led by AtkinsRéalis. OPG awarded a contract worth $450 million to the company in April, and will provide OPG with expertise for the engineering of the SMR. This includes project management, licensing, engineering, design, procurement, construction support and commissioning, as well as digital delivery capabilities in both the nuclear island and balance of plant scopes for the project.

AtkinsRéalis has been the architect-engineer on the Darlington New Nuclear Project alliance team since 2023. The company is working alongside GE Vernova Hitachi Nuclear Energy and Aecon Kiewit Nuclear Partners.

"AtkinsRéalis is a long-time trusted partner to OPG, including on the on-time, on budget Darlington Refurbishment Project," said Nicolle Butcher, OPG President and CEO. "We will draw on our shared experience for similar success as we build the first small modular reactor in the G7 at the Darlington New Nuclear Project site."