Cattenon Nuclear Power Station,

Nuclear power in Canada

Nuclear power in Canada

Canada has 18 nuclear reactors operating in the country. They are principally located in Ontario. 

The country is rich in uranium mines. Canada is the second-largest producer and exporter of uranium in the world. 13 % of the global production of uranium mining came from Canada.

Nuclear power generation accounted for 15% of Canada's electricity in 2017.

According to the World Nuclear Association: About 15% of Canada's electricity comes from nuclear power, with 19 reactors mostly in Ontario providing 13.5 GWe of power capacity.

Canada is a member of both the Nuclear Energy Agency (NEA) of the Organisation for Economic Co-operation and Development (OECD) and the International Atomic Energy Agency (IAEA). 

Are there any nuclear power plants in British Columbia?

There are not any nuclear power plants in British Columbia. Nuclear power plants and natural uranium mining are prohibited by the regional government.

In Alberta, Saskatchewan, and Nova Scotia, the energy source is primarily generated through coal and natural gas. Nuclear generation has been considered in all three provinces but has not been developed and none of the provinces have plans to build any nuclear facilities.

However, Alberta's government is considering nuclear energy for other proposals. They spotted the use of this technology to help extract oil and natural gas.

How many nuclear power plants are in Ontario?

Ontario has 3 nuclear power plants operating. All of them are composed of several nuclear reactors. In total, Ontario has 16 nuclear units working.

Additionally, Ontario has one decommissioned power plant.

Nuclear Power PlantsReactors
Bruce. Tiverton, Ontario 8

Bruce nuclear power plant

The Bruce Nuclear Power Plant is located on the eastern shore of Lake Huron in the communities of Inverhuron and Tiverton, Ontario. The property is named after Bruce County in which it is located, in the former city of Bruce.

Nuclear power in CanadaThe plant was built in stages between 1970 and 1987 from public enterprise Crown corporation, Ontario Hydro. In April 1999, Ontario Hydro was split into five components of the Crown corporation with Ontario Power Generation (OPG) taking over all power plants.

In June 2000, OPG entered into a long-term lease agreement with the private consortium Bruce Power to take over the operation of the Bruce station. In May 2001, Bruce Power started the business.

Bruce Station is the largest nuclear power plant in North America, and the second-largest in the world (after Kashiwazaki-Kariwa in Japan). It is using 8 CANDU nuclear reactors. When all units are operating they get a total gross power of 7,276 MW.

Bruce Station has two transmission lines 500  kV which are used to power the main storage centers in southern Ontario, in addition to the three lines from 230  kV serving the local zone.

Darlington Nuclear Power Plant

The Darlington nuclear power plant is located on the shore of Lake Ontario in Clarington, Ontario. The property is named after Darlington, the ancient name of the town where it is located.

Darlington station is a large nuclear facility and consists of 4 CANDU nuclear reactors. It is a combined power of 3,512 MWe (net of capacity) when all units are operating.

It provides about 20 percent of Ontario's electricity needs, enough to serve a city of two million people.

It is probably one of the most advanced nuclear power stations in the world.

Pickering Nuclear Power Plant

The Pickering nuclear power plant is located on the north shore of Lake Ontario, in Pickering.

Pickering Station is one of the largest nuclear power plants in the world and includes 8 CANDU nuclear reactors. It can supply combined power output of 4,124 MW (net of capacity) and 4,336 MW (gross) when all units are operating.

Pickering is surpassed in Canada only by the Bruce nuclear power plant, which despite having 8 reactors, has greater power. The plant is connected to the North American power grid through numerous transmission lines from 230kV and 500 kV.

The plant was built in stages between 1966 and 1986 by the Crown corporation, Ontario Hydro. In April 1999 Ontario Hydro was split into five components of the Crown corporation with Ontario Power Generation (OPG) taking overall electricity generating stations and continuing to operate at the Pickering station.

A 1.8 MWe wind turbine called the OPG 7 commemorative turbine is also connected to Pickering Station. In 1994, Pickering Unit 7 set a world record for continuous operation (894 days) without a shutdown.

The facility is operated as two separate stations, Pickering A (units 1 to 4) and Pickering B (units 5 to 8).

Nuclear accidents in the Pickering nuclear power plant

On March 16, 2011, Ontario Power Generation reported a leak of 73  m3 of slightly radioactive demineralized water coming from the secondary circuit, completely discharged into Lake Ontario. As the leak came from the secondary circuit, it was not in direct contact with the reactor.

The leak occurred two days earlier due to the failure of the seal of a recirculation pump. It would not have caused - according to government sources - any kind of damage to the environment or the ecosystem. However, the accident had a significant impact on the population, as it occurred simultaneously with the much more serious Fukushima Daiichi accident.

Douglas Point nuclear power plant - decommissioned

The Douglas Point nuclear power plant is a decommissioned power generation facility in the province of Ontario.

It was located in Kincardine, on Lake Huron, on the same site where Bruce's nuclear power plant stands today. It was in operation from 1968 to 1984.

How many nuclear power plants are in New Brunswick?

Point Lepreau Nuclear Power Plant is the unique nuclear power station in New Brunswick.

Point Lepreau Nuclear Power Plant

The Point Lepreau nuclear power plant is a Canadian nuclear power station located 2 km north-east of Point Lepreau in New Brunswick. The plant was built between 1975 and 1983 by NB Power.

Point Lepreau station is the only nuclear facility located in Atlantic Canada and comprises 1 CANDU nuclear reactor located on the northern shore of the Bay of Fundy, with a net capacity of 635 MW (680 MW gross).

The construction of a nuclear power plant in New Brunswick has been under discussion since the late 1950s. For over 15 years, engineers from the New Brunswick Electric Power Commission visited the Chalk River Laboratories of the Atomic Energy of Canada Limited corporation in Ontario to keep up with the latest trends in the field.

Official talks between Premier Richard Hatfield and the Canadian government began in 1972. Discussions accelerated the following year, in the midst of the 1973 energy crisis., as the province was looking for ways to diversify its electricity supplies and reduce its dependence on oil. However, financing the firm was a problem as the province had limited borrowing capacity.

The last hurdle was lifted by the federal government in January 1974, with the announcement of a loan program that would cover half the costs of a first nuclear power plant in a province.

Hatfield announced his intention to build the first reactor in New Brunswick on February 5, 1974. Re-elected in the fall, despite public concern, the conservative-progressive New Brunswick government followed the plan.

In March 1975, Hatfield stated on television that the decision was final and that the reactor would be built regardless of the ongoing environmental assessment process.

On May 2, 1975, the Canadian Nuclear Safety Commission authorized the construction of two 635 MW reactors on a site designed to house four at Point Lepreau, 20km west of Saint John, the largest city in New Brunswick. The NB Power began construction of a reactor, with the option for a second.

At its peak in 1979, the construction project employed 3,500 workers, and 108 out of 139 individual contracts were awarded to local businesses. Point Lepreau was licensed for operation on July 21, 1982, reached criticality four days later and began commercial operations on February 1, 1983.

How many power plants are in Québec?

Québec has only one nuclear plant operating: Gentilly nuclear power station.

Gentilly Nuclear Power Plant

The Gentilly Nuclear Power Plant ( Gentilly Nuclear Generating Station in English or Centrale nucléaire de Gentilly in French ) is a Canadian nuclear power plant located near Bécancour, Québec.

The Gentilly site contains the only power reactors in Québec (there is also a SLOWPOKE reactor at the Ecole Polytechnique de Montréal ) and includes two nuclear reactors (one CANDU-BWR prototype, now shut down, and one CANDU), located on the southern bank of the San Lorenzo River. The plant was built from two reactors built in two phases between 1966 and 1983 by the Crown corporation, Hydro-Québec, both now closed.

The property takes its name from the Gentilly suburb of the city of Bécancour, in which it is located. It is located about 100km northeast of Montreal.

Gentilly-1 - decommissioned

Gentilly-1 was a prototype of a CANDU- BWR reactor. It was designed for a net power output of 250 MW (e), a rather low power that was expected to be decisive for its export to developing countries.

The reactor had several unique characteristics among CANDU reactors, including vertically oriented pressure tubes (which allowed the use of a single refueling machine above the core), and light water coolant. These features were intended to reduce the cost and complexity of the unit, to make it attractive for export.

However, the design was unsuccessful, and over the course of 7 years, it only logged 180 days of operation. Gentilly-1 is no longer operational.


Gentilly-2 is a standard CANDU-600 reactor, similar to the one at Point Lepreau Nuclear Generating Station.

The plant has a net power output of 638 MW (e). Unlike the attached Gentilly-1 reactor, the Gentilly-2 has had an excellent service record since it started in 1982 and is scheduled to be shut down for upgrade in 2007.

The future of the plant is not yet certain. It produces only 3% of the provincial energy supply ( Quebec has large hydroelectric plants north of the province), and Hydro-Québec may decide to shut down and decommission it rather than pay for a costly upgrade.

What kind of nuclear reactors are used in Canada?

Canadian nuclear reactors are a type of pressurized heavy-water reactor (PHWR) of indigenous design, the CANDU reactor.

CANDU nuclear reactor

A CANDU (CANada Deuterium Uranium) is a nuclear reactor developed by Canada’s nuclear industry. It works with heavy water as a moderator and with natural uranium as nuclear fuel.

Nuclear power in CanadaThe main difference between a CANDU reactor and a boiling water reactor or a pressurized water reactor is that these nuclear power reactors use heavy water in the primary cooling circuit. Due to the better moderation, this means that the reactor can be made critical with natural uranium. The CANDU reactor therefore does not need enriched uranium.

All nuclear power plants in Canada use CANDU reactors. Additionally, Canada has exported 10 CANDU reactors in India, Pakistan, Argentina, South Korea, Romania, and China.

Uranium mining in Canada

For many years, North America was the world's largest uranium ore exporter and has been a major global producer since the demand for uranium developed. In 2009, Kazakhstan ranked first, relegating Canada to second place.

20% of the world’s primary uranium production came from mines in Canada in 2009. 14.5% of world production came from one mine, McArthur River.

Currently, the only producing area in Canada is northern Saskatchewan, although other areas have had active mines in the past.

Has there ever been a nuclear accident in Canada?

Canada is not exempt from nuclear accidents and incidents:

  • December 12, 1952. Chalk River Laboratories, in Ontario, Canada
    The NRX reactor suffered a nuclear accident. NRX was a heavy-water-moderated, light-water-cooled. A hydrogen explosion occurred in the reactor core due to a cascade of malfunctions and operator errors.

  • May 24, 1958, Chalk River Laboratories in Ontario, Canada. The NRU suffered a nuclear accident. The National Research Universal (NRU) reactor was a 135 MW nuclear research reactor. A fuel rod caught fire and broke when removed, then dispersed fission products and alpha-emitting particles in the reactor building.

  • November 1978. Thes accident occurred in the WR-1 Reactor at Pinawa, Manitoba, Canada. LOCA loss of coolant accident. 2,739 liters of coolant oil leaked, most of it into the Winnipeg River.

  • August 1, 1983. Pickering nuclear Reactor 2, Pickering, Ontario, Canada. Loss of coolant accident. The pressure tube, that holds the fuel bundles, ruptured due to hydriding.

  • March 1986. Bruce nuclear Reactor 2, Bruce County, Ontario, Canada. Loss of coolant accident. Pressure tube rupture during a pressurizing test (reactor shut down).

  • August 2, 1992. Pickering nuclear Reactor 1, Pickering, Ontario, Canada. A Heavy water leak of 2300 trillion becquerels of radioactive tritium into Lake Ontario, resulting in increased levels of tritium in Toronto drinking water.

  • December 10, 1994. Pickering nuclear Reactor 2, Pickering, Ontario, Canada. Loss of coolant accident. A spill of 185 tonnes of heavy water.

  • June 11, 2002. Bruce nuclear Reactor 6, Bruce B station. Bruce County, Ontario, Canada.

  • December 21, 2009. Darlington nuclear station. Clarington, Ontario, Canada Around 200,000 liters of water with trace amounts of radioactive isotope tritium coming from a storage tank mistakenly were released by workers into Lake Ontario, representing 0.1% of the monthly allowed amounts of tritium for this power plant.

  • March 14, 2011. Pickering nuclear Plant A Pickering, Ontario, Canada. A leak of 73 cubic meters (73,000 liters) of demineralized water into Lake Ontario from a failed pump seal. There was a negligible risk to the public according to the Canadian Nuclear Safety Commission.

Chalk River nuclear disasters

The Chalk River disaster was produced in Canada in 1952.

It was the first nuclear accident in history occurred when an explosion destroyed the core of one of the reactors and caused a fuel spill. Subsequent explosions blew up the four-ton dome and thousands of fissile particles were released into the atmosphere. The reactor core had to be buried.

In 1958, a second accident occurred when the uranium rods in another of the reactors overheated and broke inside the reactor. In none of the cases were any victims.

Whiteshell Laboratories

In 1963, the Government of Canada founded an AECL research laboratory in Pinawa, Manitoba, the Whiteshell Nuclear Research Establishment, now known as Whiteshell Laboratories. This facility was centered around the world's largest organically cooled, heavy water moderated nuclear reactor, the WR-1.

Also in Whiteshell, AECL built and partly operated the SLOWPOKE Reactor (SDR), to demonstrate the Slowpoke Power System, an onshore pond reactor designed to supply 10,000 kW of hot water for district heating. The project was canceled when market interest in a nuclear heating system waned.

The site comprises a number of nuclear and non-nuclear activities and facilities. In 1998, AECL decided to close Whiteshell Laboratories and many of the facilities and activities have since ceased operation.

Publication Date: September 22, 2020
Last Revision: September 22, 2020