BWRX-300 at Darlington misses 2030 target, exceeds budget

The first BWRX-300 unit at Ontario's Darlington site will miss its October 2030 commercial operation target. The project has also blown past its previously disclosed budget of C$7.7 billion. This marks a significant slip for Canada's first new nuclear build in more than three decades and the first small modular reactor to begin construction in a G7 country.

Construction of the reactor officially began in late April with the installation of the reactor building foundation. This is the project's second schedule slip; an earlier 2021 announcement had suggested a completion date as early as 2028. The same reactor design is next in line for the United States, where the Nuclear Regulatory Commission issued the Tennessee Valley Authority a construction permit for a BWRX-300 at Clinch River, Tennessee, in September.

Budget breach

The first unit's cost overrun is part of a larger four-reactor project. Ontario Power Generation plans to build four BWRX-300 units at the Darlington site with a total project budget of C$20.9 billion. The utility has confirmed the first unit will not be completed within the C$7.7 billion estimate. The reactor's pressure vessel is being assembled at a BWX Technologies plant in Cambridge, Ontario.

Ontario Power Generation attributed the problems to GE Vernova Hitachi's ongoing engineering for its first-of-a-kind reactor design, which it said impacts construction execution and supply chain performance. The utility's partners on the project include Aecon Group Inc., AtkinsRéalis Group Inc., and GE Vernova Hitachi Nuclear Energy.

Revised outlook

A comprehensive assessment of the schedule and budget impacts is now underway. Ontario Power Generation expects this revised outlook to be substantially completed by mid-2027. Chief Executive Nicolle Butcher said the company is working to establish mitigation measures and a final cost and schedule outlook.

Engineering and supply chain

GE Vernova Hitachi cited multiple interconnected factors behind the delays. A company spokesperson pointed to engineering and design maturity, the interlocking work of engineering, procurement and construction, and evolving market conditions including inflation and geopolitical risk. The BWRX-300 uses established light-water technology. "GE Vernova Hitachi is committed to working closely with Ontario Power Generation (OPG) and our partners to deliver the Western world's first commercial SMR," the spokesperson said.

Ontario Energy Minister Stephen Lecce noted the project had delivered C$362.7 million in contracts for the manufacturing base. Federal and provincial investment funds have committed up to C$3 billion for minority stakes in the project.

Industry reaction and context

The setback has drawn criticism from some quarters. Jack Gibbons of the Ontario Clean Air Alliance called for the project's cancellation, citing a history of nuclear projects being late and over budget. Proponents of small modular reactors argue that smaller, repeatable designs will be cheaper and faster to build than large-scale reactors. The hypothesis is that mass manufacturing will create a learning-curve effect, making subsequent units far cheaper. Right now, this is only a hypothesis; just two SMR plants are operating commercially worldwide, in Russia and China.

Some in the nuclear industry argue it is more economical to stick with large reactors. The recent completion of Georgia Power's Vogtle units 3 and 4 in the U.S., which took an extra seven years and $17 billion, offers a cautionary precedent. Each 300-megawatt BWRX-300 reactor is designed to produce enough carbon-free electricity to power roughly 300,000 people. Other BWRX-300 projects are planned in the United States, the United Kingdom, and Poland. Developer Blue Energy has started the U.S. Nuclear Regulatory Commission application process to build one in Texas.

Ontario Power Generation's revised assessment of cost and schedule is expected to be substantially completed by mid-2027.