The Canadian Nuclear Safety Commission (CNSC) has approved the construction of a 300-MW BWRX-300 small modular reactor (SMR) at the Darlington New Nuclear Project (DNNP), marking a significant milestone as Canada’s first grid-scale SMR.

The decision, announced on April 4, authorizes Ontario Power Generation (OPG) to begin building the GE-Hitachi-designed reactor. The license is valid until March 31, 2035, and includes four site-specific conditions, including continued Indigenous engagement, adherence to environmental assessment follow-ups, and regulatory approvals for key construction stages.

While the construction license is now in place, a separate License to Operate will be required before the unit can begin producing electricity.

The BWRX-300 is a 10th-generation SMR derived from GE’s ESBWR design and is engineered to offer lower construction costs and support uses beyond electricity generation, such as hydrogen production and district heating.

OPG selected the BWRX-300 in December 2021 and anticipates the unit could be operational by 2029, with plans to add up to three more reactors by the mid-2030s. A unique integrated project delivery (IPD) alliance backs the build, including GE Hitachi Nuclear Energy, SNC-Lavalin, and Aecon.

This approval places Canada among the first nations globally to move forward with SMRs at this scale, while supporting Ontario’s long-term electrification and energy security goals.