Pickering Nuclear Generating Station is a Canadian

nuclear power station A nuclear power plant (NPP), also known as a nuclear power station (NPS), nuclear generating station (NGS) or atomic power station (APS) is a thermal power station in which the heat source is a nuclear reactor. As is typical of thermal power st ...

located on the north shore of

Lake Ontario Lake Ontario is one of the five Great Lakes of North America. It is bounded on the north, west, and southwest by the Canadian province of Ontario, and on the south and east by the U.S. state of New York (state), New York. The Canada–United Sta ...

Pickering, Ontario Pickering (2021 Canadian census, 2021 population 99,186) is a city located in Southern Ontario, Canada, immediately east of Toronto in Durham Region, Ontario, Durham Region. Beginning in the 1770s, the area was settled by primarily British colon ...

. It is one of the oldest nuclear power stations in the world and Canada's third-largest, with eight

CANDU The CANDU (CANada Deuterium Uranium) is a Canadian pressurized heavy-water reactor design used to generate electric power. The acronym refers to its deuterium oxide (heavy water) neutron moderator, moderator and its use of (originally, natural ...

reactors. Since 2003, two of these units have been defuelled and deactivated, with two additional units being taken offline as of 2025. The remaining four produce about 11% of Ontario's power and employ 3,000 workers. A single 1.8 MWe

wind turbine A wind turbine is a device that wind power, converts the kinetic energy of wind into electrical energy. , hundreds of thousands of list of most powerful wind turbines, large turbines, in installations known as wind farms, were generating over ...

, named the OPG 7 commemorative turbine, was installed on the site of the generating station until October 2019, when it was dismantled.

Reactor codification

The reactors can be classified as follows: PICKERING A * PICKERING A 1 (Safe Shutdown state) * PICKERING A 2 (Safe Shutdown state, defuelled) * PICKERING A 3 (Safe Shutdown state, defuelled) * PICKERING A 4 (Safe Shutdown state) PICKERING B * PICKERING B 5 * PICKERING B 6 * PICKERING B 7 * PICKERING B 8

Construction

The site was once Squires Beach located west of Duffins Creek. The facility was constructed in stages between 1965 and 1986 by the provincial

Crown corporation Crown corporation () is the term used in Canada for organizations that are structured like private companies, but are directly and wholly owned by the government. Crown corporations have a long-standing presence in the country, and have a sign ...

Ontario Hydro Ontario Hydro, established in 1906 as the Hydro-Electric Power Commission of Ontario, was a publicly owned electricity utility in the Province of Ontario. It was formed to build transmission lines to supply municipal utilities with electricity ge ...

, with significant completion of Station A scheduled for 1971. In April 1999, Ontario Hydro was split into five component Crown corporations with

Ontario Power Generation Ontario Power Generation Inc. (OPG) is a Crown corporations of Canada, Crown corporation and "government business enterprise" that is responsible for approximately half of the electricity generation in the province of Ontario, Canada. It is w ...

(OPG) taking over all electricity generating stations. OPG continues to operate the Pickering station.

Operation

The Pickering station is a large multi-unit nuclear facility, comprising six operating

nuclear reactor A nuclear reactor is a device used to initiate and control a Nuclear fission, fission nuclear chain reaction. They are used for Nuclear power, commercial electricity, nuclear marine propulsion, marine propulsion, Weapons-grade plutonium, weapons ...

s with a total output of 3,114 MW when all units are on line, and two non-operating units with a total output of 1,030 MW currently shut down in safe storage. The facility is connected to the North American power grid via numerous 230 kV and 500 kV transmission lines. The facility was operated as two distinct stations, Pickering A (Units 1 to 4) and Pickering B (Units 5 to 8) until 2011. While primarily administrative in nature, the division was not wholly artificial, as there are some distinct differences in design between the two groups of stations. (Example: The Pickering A units employ a moderator dump as a shutdown mechanism, a feature not found in Pickering B, which instead uses what is called an over-poisoned reaction guaranteed shutdown.) There are, however, a number of systems and structures in common between the two stations; the most notable of these is the shared vacuum building, a negative pressure containment system. The operation of Pickering A and B was unified in 2010, to reduce costs now that Pickering A Units 2 and 3 are shut down in safe storage.

Partial shutdown

On December 31, 1997 the four Pickering A reactors, along with the remaining three units at Bruce A, were shut down by

for safety reasons and placed in lay-up. Specific to Pickering A, four years earlier the AECB had required mandatory upgrades to the safe shutdown system be completed by the end of 1997, which differed from that at the other three plants. Pickering A featured a moderator dump as its 2nd shutdown system, and this was deemed too slow compared to the poison injection system that later plants used, including Pickering B. Ontario Hydro committed to the refit and restart project, but it underwent long delays and large cost over-runs.

Safety System Refit

Often called a refurbishment, the return to service of Pickering A units 1 and 4 did not involve refurbishing the reactor cores, which involves replacing the calandria tubes, pressure tubes, feeders and end fittings. The main scope of work was the upgrading of the secondary safe shutdown system as well as some maintenance. Instead of retrofitting the poison injection found at the other plants, the least cost option was to add more shutdown rods and then split them into separate, independent groups. This was deemed sufficient by the AECB, despite acknowledging that this does not in fact constitute a fully independent fast acting secondary safe shutdown system.

Return to service

Premier

Mike Harris Michael Deane Harris (born January 23, 1945) is a retired Canadian politician who served as the 22nd premier of Ontario from 1995 to 2002 and leader of the Progressive Conservative Party of Ontario (PC Party) from 1990 to 2002. Taking the PC ...

asked former federal energy Minister

Jake Epp Arthur Jacob "Jake" Epp, (born September 1, 1939) is a Canadians, Canadian executive and former politician. Life and career Born into a Mennonite family in Manitoba, Epp was a high school history teacher in Steinbach, Manitoba before entering ...

to study and make recommendations on the problems with the Pickering restart. The review panel was established in May 2003. Unit 4 was refitted and then restarted in Sept. 2003. The election of the

Ontario Liberal Party The Ontario Liberal Party (OLP; , PLO) is a political party in the province of Ontario, Canada. The party has been led by Bonnie Crombie since December 2023. The party espouses the principles of liberalism, with their rival the Progressive Co ...

in October 2003 delayed action on the Epp report. In late 2003, the new government fired the top three executives of OPG for botching the Unit 4 restoration, which was years late and millions of dollars over budget. Mr. Epp and the Pickering A Review Panel released their report in December 2003, which acknowledged the large cost over-runs and delays, attributing blame to bad management. The Epp Review estimated the cost of restarting the remaining three reactors at $3 – 4 billion and supported the continuation of the project. The government of

Dalton McGuinty Dalton James Patrick McGuinty Jr. (born July 19, 1955) is a Canadian former politician who served as the 24th premier of Ontario from 2003 to 2013. He was the first Liberal leader to win two majority governments since Mitchell Hepburn nea ...

appointed Epp to the Ontario Power Generation Review headed by

John Manley John Paul Manley (born January 5, 1950) is a Canadian lawyer, businessman, and politician who served as the eighth deputy prime minister of Canada from 2002 to 2003. He was Liberal Member of Parliament for Ottawa South from 1988 to 2004. ...

to examine the future role of

(OPG) in the province's

electricity market An electricity market is a system that enables the exchange of electrical energy, through an electrical grid. Historically, electricity has been primarily sold by companies that operate electric generators, and purchased by consumers or electr ...

, examine its corporate and management structure, and decide whether the public utility should proceed with refurbishing three more nuclear reactors at the Pickering

nuclear power Nuclear power is the use of nuclear reactions to produce electricity. Nuclear power can be obtained from nuclear fission, nuclear decay and nuclear fusion reactions. Presently, the vast majority of electricity from nuclear power is produced by ...

plant. The report recommended proceeding with the restart of Pickering “A” reactors 1, 2, and 3, sequentially. The report argued that the restart of units 2 and 3 would be contingent on whether “OPG will be able to succeed at the Unit 1 project." The McGuinty government accepted the OPG Review Committee's recommendation and allowed the refit and restart of reactor 1. The anti-nuclear group

Sierra Club The Sierra Club is an American environmental organization with chapters in all 50 U.S. states, Washington, D.C., Washington D.C., and Puerto Rico. The club was founded in 1892, in San Francisco, by preservationist John Muir. A product of the Pro ...

of Canada criticized the 2004 OPG Review Committee report for not attributing any blame to the problems of nuclear technology, noting that there were no energy or environmental experts appointed to the panel. Numerous changes in executive-level staff and project management strategy were made for the follow-on project to refit Unit 1. The experience with the return to service of Pickering A Unit 1 was significantly different from Unit 4, with a much tighter adherence to schedule and budget. In August 2005, the OPG Board of Directors announced that Units 2 and 3 would not be returned to service due to specific technical and cost risks surrounding the material condition of these two units. Unit 1 was returned to service in November 2005.

Electrical Output

The graph represents the annual electricity generation at the site (A and B combined) in GWh. ImageSize = width:621 height:430 PlotArea = left:45 right:5 top:25 bottom:30 TimeAxis = orientation:vertical AlignBars = late Colors = id:linegrey2 value:gray(0.9) id:linegrey value:gray(0.7) id:cobar value:rgb(0.2,0.7,0.8) id:cobar2 value:rgb(0.6,0.9,0.6) DateFormat = yyyy Period = from:0 till:25000 ScaleMajor = unit:year increment:1000 start:0 gridcolor:linegrey ScaleMinor = unit:year increment:500 start:0 gridcolor:linegrey2 PlotData = color:cobar width:19 align:left bar:2001 from:0 till:13121 bar:2002 from:0 till:14490 bar:2003 from:0 till:13119 bar:2004 from:0 till:15813 bar:2005 from:0 till:17370 bar:2006 from:0 till:19919 bar:2007 from:0 till:17005 bar:2008 from:0 till:19248 bar:2009 from:0 till:20708 bar:2010 from:0 till:19217 bar:2011 from:0 till:19629 bar:2012 from:0 till:20761 bar:2013 from:0 till:19734 bar:2014 from:0 till:20154 bar:2015 from:0 till:21297 bar:2016 from:0 till:20017 bar:2017 from:0 till:21510 bar:2018 from:0 till:20911 bar:2019 from:0 till:23657 bar:2020 from:0 till:20629 bar:2021 from:0 till:21165 bar:2022 from:0 till:21464 bar:2023 from:0 till:21543 TextData= fontsize:S pos:(20,20) text: Pickering Nuclear Generating Station As of the end of 2023, the total lifetime output of the facility was 972,252 GWh.

Costs

Construction Costs

Ontario Hydro estimated the construction cost for the four Pickering "A" units at $508 million in 1965. Actual cost was $716 million (in 1973 dollars). Adjusted for inflation, the $508 million estimate in 1973 dollars is $698 million, a 2.6% overrun. The 1974 estimated cost for the four Pickering "B" units was $1.585 billion. Final cost was $3.846 billion (1986 dollars). Adjusted for inflation, the $1.585 billion estimate in 1986 dollars is $4.082 billion, putting Pickering B under budget.

Safety Refit Costs

According to Ontario's FAO, the cost for refitting and restarting the Pickering A units deviated significantly from projections.
- Pickering Unit 4 was slated to cost $460 million and ultimately ended up costing $1.25 billion.
- Pickering Unit 1 was slated to cost $210 million and ultimately ended up costing $1.00 billion. However, the figure presented by the FAO for Unit 1 doesn't align with that provided by Ontario Energy Minister, Dwight Duncan, who indicated that Pickering Unit 1 would cost $900 million, putting the completed project much closer to budget. This is supported by OPG stating that the project was completed on time and on budget.

Waste

The

used nuclear fuel Spent nuclear fuel, occasionally called used nuclear fuel, is nuclear fuel that has been irradiated in a nuclear reactor (usually at a nuclear power plant). It is no longer useful in sustaining a nuclear reaction in an ordinary thermal reactor and ...

and some refurbishment waste generated by the plant sits on-site at the Pickering Waste Management Facility. All operational low and intermediate-level waste is transported to OPG's Western Waste Management Facility at the Bruce nuclear site near

Kincardine, Ontario Kincardine ( ) is a municipality located on the shores of Lake Huron in Bruce County in the province of Ontario, Canada. The current municipality was created in 1999 by the amalgamation of the Town of Kincardine, the Township of Kincardine, an ...

. OPG has proposed the construction and operation of a deep geologic repository for the long-term storage of low and intermediate level waste on lands adjacent to the Western Waste Management Facility. The Nuclear Waste Management Organization is currently seeking a site for a potential repository for the used fuel from all Canadian nuclear reactors.

Records

On October 7, 1994, Pickering Unit 7 set the world record for continuous runtime at 894 days, a record that stood for 22 years. It was surpassed by Heysham 2 unit 8 in 2016, a facility located in the UK, owned by EDF. This was subsequently surpassed by OPG's Darlington plant with Unit 1 running 1,106 consecutive days.
- In 2019, Pickering set a site capacity factor record of 87.07%, producing 23.6TWh and putting it roughly on-par with the much newer Darlington and Bruce facilities.
- On May 19th, 2025, the Pickering B units pushed the lifetime production of the Pickering facility over the 1PWh threshold. It joins Bruce in having reached this milestone.

Future

In January 2016, the Province of Ontario approved plans to pursue continued operation of the Pickering Nuclear Generating Station to 2024. The extension was intended to ensure sufficient base load electricity was available during refurbishment of the

Darlington Nuclear Generating Station Darlington Nuclear Generating Station is a Canadian nuclear power station located on the north shore of Lake Ontario in Bowmanville, Ontario. It is a large nuclear facility comprising four CANDU reactor, CANDU nuclear reactors with a total outpu ...

and the initial Bruce Nuclear refurbishments. By 2016, OPG had begun planning for the end of commercial operations at the generating station, including the potential repurposing of the Pickering site location. OPG will begin the longer term decommissioning process if refurbishment is not pursued. The first step in the long-term decommissioning process is to layup the reactors and place them into safe storage. Pickering staff will have future employment opportunities placing the Pickering units in a safe storage state, at the Darlington refurbishment and operations, or at the potential new build at Darlington. In September 2022, the Province of Ontario announced that it supported an extension of Pickering's operation from 2024 to 2026. Simultaneously, it announced that it had requested OPG to update feasibility studies on the potential refurbishment of the four units of Pickering B. In its announcement, the Province stated that continued operation of the station would reduce carbon dioxide emissions by 2.1 megatonnes in 2026, as well as increasing the North American supply of

cobalt-60 Cobalt-60 (Co) is a synthetic radioactive isotope of cobalt with a half-life of 5.2714 years. It is produced artificially in nuclear reactors. Deliberate industrial production depends on neutron activation of bulk samples of the monoisotop ...

, a

medical isotope A medical isotope is an isotope used in medicine. The first uses of isotopes in medicine were in radiopharmaceuticals, and this is still the most common use. However more recently, separated stable isotopes have come into use. Radioactive isotope ...

. In August 2023, the OPG Board of Directors agreed with and authorized the submission of the feasibility assessment for the refurbishment of the Pickering B plant to the province as well as to proceed with preliminary planning and preparation activities for the project. This feasibility report was given to the Minister of Energy in January 2024 but was not released to the public because it could harm the "economic or other interests of Ontario.” On January 30, 2024, the Minister of Energy,

Todd Smith Todd Smith may refer to: People * Todd Smith (musician), American singer, songwriter and guitarist * Todd Smith (politician), Canadian politician *Todd Smith, American vocalist and member of Selah * Todd Smith (wrestler), American wrestler * Todd ...

, announced that the Government of Ontario would be investing in the refurbishment of the four Pickering B reactors that date back to the early 1980s. The refurbishment is expected to be complete by the mid 2030s and should extend the life of the plant by at least another 30 years. On October 1, 2024 at 11PM, Pickering 1 was removed from service as planned, as part of the A plant shutdown process. On December 31, 2024 at 12PM, Pickering 4 was removed from service, the final step in the A plant shutdown process.

Incidents

A serious incident occurred on August 1, 1983. Pressure tube G16 in the Pickering A Unit 2 reactor developed a 2-metre-long split. The reactor was safely shut down and the damage investigated. The cause was found to be the mis-location of annulus gas spacer springs which allowed the hot pressure tube to sag and touch the inside of the cold calandria tube leading to hydrogen enrichment of the cooler areas. This created a series of small cracks which linked up and caused the long rupture. There was some local fuel damage and the reactor was safely shut down by the operators with no increase in radioactive emissions. The eventual resolution was Large Scale Fuel Channel Replacement and all the pressure tubes were replaced in all Pickering A reactors. The new pressure tubes were supported by an improved design of the annulus gas spacer springs. Since then, careful monitoring of the location of the annulus gas spacer rings has been a significant part of routine reactor inspections. On December 10, 1994, there was a loss of coolant accident. It is said to be the most serious accident in Canadian history (June 2001) by The Standing Senate Committee on Energy, the Environment and Natural Resources. The Emergency Core Cooling System was used to prevent a meltdown. In 1995 and 1996, the AECB noted many safety concerns with the plant, and the generating station was shut in 1997 after peer reviews describing poor safety practices at the plant became public. An Independent, Integrated Performance Assessment report noted that Pickering stations A and B were cited for breaking regulation 15 times and having 13 fires for the year. "Also of concern was the high failure rate of persons being tested for positions as nuclear operators. At Pickering A only 65% of those taking the test passed, while at Pickering B the rate was just 56%." On March 14, 2011, there was a leak of 73 cubic metres of

demineralized water Water purification is the process of removing undesirable chemicals, biological contaminants, suspended solids, and gases from water. The goal is to produce water that is fit for specific purposes. Most water is purified and disinfected for hu ...

into Lake Ontario from a failed pump seal. There was negligible risk to the public according to the

Canadian Nuclear Safety Commission The Canadian Nuclear Safety Commission (CNSC; ) is the federal regulator of nuclear power and materials in Canada. Mandate and history Canadian Nuclear Safety Commission was established under the 1997 '' Nuclear Safety and Control Act'' with a ma ...

2020 nuclear incident alert

On January 12, 2020 at 7:24 a.m. ET, an

emergency alert An emergency is an urgent, unexpected, and usually dangerous situation that poses an immediate risk to health, life, property, or environment and requires immediate action. Most emergencies require urgent intervention to prevent a worsening ...

was issued via

Alert Ready The National Public Alerting System (NPAS; ), branded as Alert Ready (), is the national warning system in Canada, broadcast to Canadian television, radio, and wireless devices. The system consists of infrastructure and standards for the presen ...

on all radio stations, television stations, television providers, and wireless networks in the province of Ontario, containing an advisory of an unspecified "incident" that had been reported and was being addressed at the plant. The alert stated that no immediate action was required for those within of the plant. Approximately 40 minutes later, OPG issued a statement via

Twitter Twitter, officially known as X since 2023, is an American microblogging and social networking service. It is one of the world's largest social media platforms and one of the most-visited websites. Users can share short text messages, image ...

that the alert had been sent in error, and a second emergency alert was issued at around 9:10 a.m. with a similar message cancelling the previous alert.

Solicitor General A solicitor general is a government official who serves as the chief representative of the government in courtroom proceedings. In systems based on the English common law that have an attorney general or equivalent position, the solicitor general ...

Sylvia Jones Sylvia Jones (born ) is a Canadian politician who has served as the deputy premier of Ontario and minister of health since June 24, 2022. Jones sits as the member of Provincial Parliament (MPP) for Dufferin—Caledon, representing the Prog ...

stated that the alert was accidentally issued during a "routine training exercise" by Ontario's

emergency operations centre An emergency operations center (EOC) is a central command and control "coordination structure" responsible for managing Emergency service, emergency response, emergency preparedness, emergency management, and disaster management functions at a s ...

. The incident prompted criticism from government officials, including MPP

Peter Tabuns Peter Charles Tabuns (born October 3, 1951) is a Canadian politician who served as the interim leader of the Ontario New Democratic Party and the Leader of the Official Opposition (Ontario), leader of the Official Opposition from 2022 to 2023. ...

, Pickering mayor Dave Ryan, and

Toronto Toronto ( , locally pronounced or ) is the List of the largest municipalities in Canada by population, most populous city in Canada. It is the capital city of the Provinces and territories of Canada, Canadian province of Ontario. With a p ...

mayor

John Tory John Howard Tory (born May 28, 1954) is a Canadian lawyer, broadcaster, businessman, and former politician who served as the 65th mayor of Toronto from 2014 to 2023. He served as leader of the Official Opposition in Ontario from 2005 to 2007 ...

. The false alarm also prompted renewed interest in preparedness for actual

nuclear accident A nuclear and radiation accident is defined by the International Atomic Energy Agency (IAEA) as "an event that has led to significant consequences to people, the environment or the facility." Examples include radiation poisoning, lethal effect ...

s: OPG reported a surge in the sales of

potassium iodide Potassium iodide is a chemical compound, medication, and dietary supplement. It is a medication used for treating hyperthyroidism, in radiation emergencies, and for protecting the thyroid gland when certain types of radiopharmaceuticals are u ...

kits via its "Prepare to Be Safe" website between January 12 and 13, increasing from its monthly average of 100–200 to over 32,000. The website is applicable for those who live within of the plant; per

(CNSC) requirements, OPG is required to distribute these pills to all residences within of a nuclear facility.

References

External links

Ontario Power Generation

Google maps satellite image
{{Authority control Nuclear power stations in Ontario Ontario Hydro Ontario Power Generation Pickering, Ontario Nuclear power stations using CANDU reactors Buildings and structures in the Regional Municipality of Durham Energy infrastructure completed in 1971 Energy infrastructure completed in 1983 1971 establishments in Ontario