Canada has one of the world’s most established nuclear industries, but its current importance is not based only on the reactors already producing electricity. The country combines operating power plants, uranium mining, fuel production, engineering expertise, medical isotope manufacturing and the Canadian-designed CANDU reactor system.
Most Canadian nuclear generation is concentrated in Ontario, where the Bruce, Darlington and Pickering stations form the centre of the provincial electricity system. New Brunswick operates the Point Lepreau station, while other provinces are considering whether small modular reactors could support future power demand.
The central question facing the industry has changed. Canada is no longer deciding only how long to operate its existing plants. It is beginning to decide what kind of nuclear fleet should follow them.
CANDU Reactors Remain at the Centre of Canadian Nuclear Power
Canada’s operating nuclear power reactors use CANDU technology. These pressurized heavy-water reactors can use natural uranium rather than requiring enriched uranium fuel. They also use pressure tubes instead of the large reactor pressure vessel found in most commercial light-water reactors.
This design shaped a domestic industry extending from uranium production in Saskatchewan to fuel manufacturing, heavy-water expertise, reactor services and specialized engineering. CANDU reactors have also been exported to Argentina, China, India, Pakistan, Romania and South Korea, although some countries later developed their own reactor programs from the technology.
Within Canada, nuclear generation remains heavily concentrated in Ontario. Bruce Power operates eight units on the eastern shore of Lake Huron. Ontario Power Generation operates four units at Darlington and four active units at Pickering, while NB Power operates the single-unit Point Lepreau station.
Nuclear supplied 48.2% of Ontario’s electricity generation in 2025, despite several units being unavailable during planned refurbishment and maintenance outages. The technology therefore serves as a source of continuous bulk electricity rather than a small supporting part of the provincial system.
Canada-wide, nuclear contributes a smaller share because hydroelectricity dominates several other provinces. Its national importance is nevertheless larger than its generation percentage suggests. Nuclear supports Ontario’s industrial economy and provides a major source of electricity without direct carbon emissions from generation.
Refurbishment Has Become Canada’s Main Nuclear Construction Program
The most important Canadian nuclear projects of the past decade have involved rebuilding existing CANDU reactors rather than constructing entirely new stations.
Ontario Power Generation completed the refurbishment of Darlington’s four reactors after carrying out the work one unit at a time. The program replaced major reactor components, including pressure tubes, calandria tubes and feeder systems, allowing the station to operate for several more decades. The project was completed ahead of its revised schedule and below its approved budget.
Bruce Power is conducting a similar life-extension program. Its Major Component Replacement work covers Units 3 through 8 and is expected to extend operation at the site into the 2060s. The Unit 6 refurbishment was completed in 2023, while work on Units 3 and 4 followed. Unit 5 is scheduled to enter its refurbishment outage in late 2026.
Pickering represents the next major decision. Its older Units 1 and 4 ended commercial operation in 2024, while Units 5 through 8 are authorized to operate until the end of 2026. Ontario Power Generation is preparing to refurbish those four reactors, with the goal of returning them to service during the mid-2030s and extending their operating lives by more than 30 years.
This experience has allowed Canada to preserve engineering knowledge and a qualified nuclear supply chain during a long period without major new reactor construction. It has also shown that refurbishment can function as an alternative to replacing an entire station, especially when transmission connections, cooling systems and other infrastructure are already in place.
Darlington Moves Canada into Commercial SMR Construction
The Darlington New Nuclear Project marks a different stage in Canada’s nuclear development. Ontario approved construction of the first BWRX-300 small modular reactor at the site in May 2025, and the project is now under construction.
The BWRX-300 is a 300-megawatt boiling-water reactor designed by GE Hitachi Nuclear Energy. Unlike Canada’s existing CANDU fleet, it uses light-water reactor technology and enriched uranium fuel. Ontario Power Generation plans to develop as many as four units at Darlington, creating a potential 1,200-megawatt station.
The first project is important because many proposed SMRs around the world remain in design, licensing or demonstration stages. Darlington is intended to establish a commercial reference plant that can be repeated at the same site and potentially in other provinces.
SaskPower has selected the BWRX-300 as the technology it would use if Saskatchewan enters nuclear generation. The utility is conducting site, regulatory and planning work, although a final investment decision is not expected until 2029. A first Saskatchewan unit could operate in the mid-2030s if the project proceeds.
New Brunswick has explored different advanced-reactor designs, including smaller systems that could potentially support industrial heat, electricity generation or future fuel-cycle applications. These projects are less advanced than the Darlington development, illustrating that Canada’s SMR market is likely to progress at different speeds in different provinces.
Large Reactors Return to Canada’s Long-Term Planning
Small reactors are only one part of Canada’s nuclear plans. Ontario is also preparing for possible large-scale construction as electricity demand grows.
Bruce Power is advancing the proposed Bruce C project, which could add as much as 4,800 megawatts at the existing Bruce site. The project is in the impact-statement phase of the federal assessment process. No final reactor technology or construction decision has been made, but the proposal would represent Canada’s first new large nuclear station in several decades.
Ontario has also identified the former Wesleyville generating site near Port Hope as a possible location for substantial future nuclear capacity. These plans remain at an early stage, but they show how rapidly the provincial discussion has shifted from managing an existing fleet to preparing multiple new-build options.
Growing power requirements are driving this change. Electrification, electric vehicles, manufacturing, data centres and population growth are expected to raise Ontario’s electricity demand significantly through 2050. Nuclear generation is being considered alongside hydroelectricity, renewables, storage, transmission expansion and natural gas capacity.
Canada is also supporting development of the next-generation CANDU MONARK design. The modernized reactor is intended to maintain the domestic CANDU supply chain while incorporating updated safety, construction and operating features. Its development gives future Canadian projects a domestic large-reactor option rather than limiting procurement to foreign designs.
Uranium Gives Canada a Wider Role in the Global Nuclear Market
Canada’s nuclear position extends beyond electricity generation. Saskatchewan contains some of the world’s highest-grade commercial uranium deposits, with production centred in the Athabasca Basin.
Approximately 90% of Canadian uranium production is available for export. Canada was also the largest foreign supplier of uranium purchased by United States nuclear operators in 2024, accounting for about one-third of those purchases.
The country has capabilities in uranium mining, refining, conversion and CANDU fuel manufacturing. Canadian companies also provide reactor engineering, components, inspection services, control systems, maintenance and isotope-production technology.
This integrated industrial base gives nuclear policy an international trade dimension. Canada can supply uranium and nuclear services even to countries that do not operate CANDU reactors. It can also offer CANDU life-extension work to existing international operators and pursue exports of modernized reactor technology.
Used Fuel Management Enters a Regulatory Phase
Long-term management of used nuclear fuel remains necessary for both the existing fleet and any future reactors.
In 2024, the Nuclear Waste Management Organization selected the Revell Batholith area in northwestern Ontario as the proposed location for Canada’s deep geological repository. Wabigoon Lake Ojibway Nation and the Township of Ignace agreed to move forward as potential host communities.
The repository has not yet been constructed or licensed. It must pass federal impact assessment and regulatory review before development can begin. Used fuel therefore continues to be stored safely at reactor sites while the project advances.
Future reactor technologies may produce different fuel and waste streams, particularly if Canada deploys enriched-fuel SMRs alongside natural-uranium CANDU reactors. Waste planning, fuel supply and repository capacity will consequently remain part of new-build decisions.
Canada Is Moving from Fleet Preservation to Nuclear Expansion
Canada’s immediate nuclear future still depends on completing CANDU refurbishments safely and returning units to reliable service. Darlington, Bruce and Pickering will determine how much existing capacity remains available through the middle of the century.
The longer-term direction is more expansive. Construction at Darlington, planning in Saskatchewan, the Bruce C assessment and development of CANDU MONARK show that nuclear energy is again being treated as a growth industry.
The outcome will depend on whether Canada can repeat its recent refurbishment performance in new construction. Successful delivery of the first Darlington SMR would strengthen the case for a multi-unit fleet. Effective planning for large reactors would allow Canada to preserve its domestic technology and supply chain while meeting rising electricity demand. Nuclear power is therefore moving from an inherited part of Canada’s energy system toward a central element of its future industrial and electricity strategy.
