The Ontario government is working with Ontario Power Generation (OPG) to begin planning and licensing for three more BWRX-300 small modular reactors (SMRs) at the Darlington NPP site for a total of four.

In October 2022, OPG applied to the Canadian Nuclear Safety Commission (CNSC) for a licence to construct a GE Hitachi Nuclear Energy (GEH) BWRX-300 at the Darlington site. This licence is required before any nuclear construction work on the SMR can begin. The following December OPG broke ground to prepare for the first grid-scale SMR in Canada. OPG is partnering with GEH, SNC-Lavalin, and Aecon on the project, with construction of the first unit scheduled to be complete by 2028.

The BWRX-300 is a 300 MWe water-cooled, natural circulation SMR with passive safety systems that leverages the design and licensing basis of GEH's ESBWR boiling water reactor. The CNSC issued a positive decision in March, making the BWRX-300 the first SMR to complete such a pre-licensing Vendor Design Review in Canada. Subject to Ontario Government and CNSC regulatory approvals on construction, the additional SMRs could come online between 2034 and 2036.

This timing would allow OPG to apply learnings from the construction of the first unit to deliver cost savings on subsequent units, the government noted. Building multiple units will also allow common infrastructure such as cooling water intake, transmission connection and control room to be utilised by all four units instead of just one, reducing costs even further.

"Once deployed, these four units would produce a total 1200 megawatts of electricity, equivalent to powering 1.2 million homes, helping to meet increasing demand from electrification and fuel the province's strong economic growth," the government noted.

Todd Smith, Minister of Energy, said: “Expanding Ontario’s world-leading SMR programme will ensure we have the reliable, affordable and clean electricity we need to power the next major international investment, the new homes we are building and industries as they grow and electrify.”

“A fleet of SMRs at the Darlington New Nuclear Site is key to meeting growing electricity demands and net zero goals,” said Ken Hartwick, OPG President and CEO. “OPG has proven its large nuclear project expertise through the on-time, on budget Darlington Refurbishment project. By taking a similar approach to building a fleet of SMRs, we will deliver cost and schedule savings, and power 1.2 million homes from this site by the mid-2030s.”

Ontario’s robust nuclear supply chain is uniquely positioned to support SMR development and deployment in Ontario, Canada and globally, the Ontario government said. “Building additional SMRs at Darlington would provide more opportunities for Ontario companies as suppliers of nuclear equipment, components, and services to make further investments to expand their operation to serve the growing SMR market both domestically and abroad.”

The Darlington SMR project is situated on the traditional and treaty territories of the seven Williams Treaties First Nations and is also located within the traditional territory of the Huron Wendat peoples. OPG consulting with potentially impacted Indigenous communities, including exploring economic opportunities in the Darlington SMR project such as commercial participation and employment.

Image: Todd Smith, Ontario's Minister of Energy, and Ken Hartwick, OPG President & CEO, announce plans for additional SMRs at Darlington NPP (courtesy of OPG)