Ontario and Ontario Power Generation (OPG) have approved construction of GE Vernova Hitachi Nuclear Energy’s (GVH’s) BWRX-300 small modular reactor. This clears the way for construction of the first of four planned BWRX-300s at OPG’s Darlington site to begin soon with completion of the first unit scheduled by the end of the decade.

Early site preparation work at Darlington has been completed and in April the Canadian Nuclear Safety Commission granted OPG a licence to construct the first unit. The 300 MWe BWRX-300, a 10th generation design, builds on decades of real-world boiling water reactor operating experience and innovation, using a standard design, a proven delivery model and GVH’s experience with cross-border regulatory collaboration.

“In deploying the first BWRX-300 small modular reactor, Ontario is leading the way globally in the deployment of SMRs,” said Maví Zingoni, CEO, Power at GE Vernova. “Our work with OPG and project partners will serve as a benchmark for the global nuclear industry.”

Lisa McBride, Canada Country Leader at GVH noted: “As the world looks to adopt SMR technology, we are proud to be embarking on construction of the first BWRX-300 with OPG, AtkinsRéalis and Aecon” said. “Ontario’s supply chain is expected to contribute significantly to this project bringing substantial economic benefits to the province including the creation of thousands of jobs during manufacturing, construction and operation.

The announcement comes weeks after GVH submitted its final proposal to the Great British Nuclear SMR competition. “The decision to proceed with construction in Canada means our BWRX-300 is the only SMR in the Western world with a contract to deploy, making us the lowest risk choice in the Great British Nuclear SMR competition,” GVH said. “We look forward to a decision from the UK government to move forward with two technologies this Spring.

Construction of the BWRX-300 reactor adjacent to OPG’s existing Darlington Nuclear Station will produce enough energy to power 300,000 homes. “Successful deployment at Darlington will demonstrate the feasibility and benefits of SMRs, encouraging broader adoption and investment in this transformative technology,” OPG said in a statement.

Four units are eventually planned for the site and are expected to be operating by 2035. The total project cost is put at CAD20.9bn ($15.06bn), Ontario Energy Minister Stephen Lecce told a news briefing.

State of play: The planned reactors will help meet what provincial officials expect to be a 75% rise in Ontario’s power demand by 2050, Lecce said. Building the four reactors would bring up to 18,000 Canadian jobs and add CAD38.5bn to Canada’s GDP over the next 65 years.

“As we confront the challenges of increased demand, energy security and carbon intensity, this milestone reaffirms our commitment to innovation and a more sustainable energy future,” GE Vernova CEO Scott Strazik said in a statement.

“This is truly a historic moment,” said Nicolle Butcher, OPG’s President & CEO. “This made-in-Ontario project will support provincial companies, create jobs for Ontarians, and spur growth for our economy. OPG is proud to be leading this first-of-a-kind project. With the province’s robust nuclear supply chain and our successful track record on nuclear projects, particularly our Darlington Refurbishment, we are confident we will be able to deliver the first SMR unit for Ontario, on-time and on-budget.”

She added: “As a first mover on SMRs, Ontario will also be able to market our capabilities and nuclear expertise to the world to further grow our domestic industry.”

Since late 2022, dozens of trucks have been busy relocating clean soil across the site to level out the lands intended for the future SMR units. Crews have been installing various utilities, including fire lines, water lines, sanitary sewer lines, and network cabling. Construction on a few important buildings, including the on-site fabrication building, is also progressing. The team continues to excavate for the Reactor Building shaft in preparation for construction of the reactor building.

OPG’s SMR project team recently visited BWXT at their Cambridge facility to observe the beginning of fabrication for cladding of the first SMR’s reactor pressure vessel (RPV), the largest component of the SMR unit. The 550-tonne RPV, which will contain the reactor core, coolant, and support structures, is 30 metres long and over six metres in diameter.

Meanwhile, the generator rotor – a key component of the turbine-generator system that converts heat from the reactor into electrical power – has been forged and is now undergoing pre-machining for delivery to the project site by summer 2027.

Later this summer, the project’s tunnel boring machine will arrive from Germany at the site for storage until assembly in early 2026. Once operational, it will be used to drill the condenser cooling water tunnel, which will measure 3.4 kilometres long and 6.05 metres in diameter.