The Canadian Nuclear Safety Commission granted Ontario Power Generation a construction licence on April 4, 2025, to build one BWRX-300 small modular reactor at the Darlington site. The licence clears the way for physical construction to begin — a critical regulatory threshold that moves the project from the preparation phase into active building.

Financing for the project has been layered in from multiple sources. Ontario committed $1 billion in provincial funding in October 2025. That same month, the Canada Growth Fund and the Building Ontario Fund announced an equity commitment agreement — a pairing of a federal Crown finance corporation with a provincial investment vehicle that is uncommon in major energy deals. The Canada Infrastructure Bank added $970 million in low-interest debt financing. Natural Resources Canada confirmed additional federal investments in March 2025. OPG's first-quarter 2025 results showed the corporation had already spent $1 billion on the project, moving Ontario's commitment from announcement into actual expenditure.

Indigenous Equity: The Emerging Ownership Structure

Ontario's Environmental Registry notice from January 2026 lists Indigenous partnerships as a policy priority for Darlington. The province's Indigenous Opportunities Financing Program — which provides loan guarantees allowing First Nations to take equity stakes in energy projects — is the existing tool for that participation. The Globe and Mail has reported that Ottawa and Ontario are expected to announce a joint Indigenous loan guarantee specifically for the nuclear project, bringing federal backing alongside provincial support.

A loan guarantee works differently from a direct grant. It does not hand over risk to a First Nation; instead, it lowers the cost of borrowing to near-government rates, making equity participation commercially realistic for communities that would otherwise face steep financing costs on a project of this scale and timeframe. A federal-provincial co-guarantee would split the contingent liability — the backing obligation — across two government balance sheets.

OPG's Q1 results also noted that the corporation is separately exploring Indigenous-led hydro projects in Northern Ontario, signalling that the broader OPG-Indigenous equity model extends beyond the Darlington nuclear file.

What the Licence Authorizes

The licence runs until 2035, aligned with the projected construction timeline for the first BWRX-300 unit. The BWRX-300 is GE-Vernova's 300-megawatt small modular design. It builds on GE's established ESBWR reactor lineage but adds passive safety systems — mechanisms that work without active pumps or human intervention if something goes wrong — and requires far less concrete and civil work than a conventional large reactor. Darlington will be the first commercial deployment of this design anywhere globally.

Ontario has projected the project will create thousands of jobs and supply power to thousands of homes. Those are government estimates rather than independently verified figures, though the scale is consistent with comparable nuclear construction.

The financing structure — provincial equity, federal equity through the Growth Fund, Infrastructure Bank debt, and a prospective joint loan guarantee for Indigenous equity — spreads both the capital and the political weight of the project across multiple governments and communities. That distribution also splits the schedule and cost risk that has historically made nuclear projects difficult to sustain through election cycles. Whether this structure holds as active construction proceeds will partly depend on how cost projections change as detailed engineering advances.