Bruce Nuclear Generating Station is a nuclear power station located on the eastern shore of Lake Huron in Ontario, Canada. It occupies 932 ha (2300 acres) of land. The facility derives its name from Bruce Township, the local municipality when the plant was constructed, now Kincardine due to amalgamation. With eight CANDU pressurized heavy-water reactors, until 2016, it was the world's largest fully operational nuclear generating station by total reactor count and the number of currently operational reactors. In 2016, it was exceeded in nameplate capacity by South Korea's Kori Nuclear Power Plant. The station is the largest employer in Bruce County, with over 4000 workers.
Formerly known as the Bruce Nuclear Power Development (BNPD), the facility was constructed in stages between 1970 and 1987 by the provincial Crown corporation, Ontario Hydro. In April 1999 Ontario Hydro was split into 5 component Crown corporations with Ontario Power Generation (OPG) taking over all electrical generating stations. In June 2000, OPG entered into a long-term lease agreement with private sector consortium Bruce Power to take over operation. In May 2001, Bruce Power began operations. The lease was for 18 years until 2019 with an option to extend another 25 years to 2044.
In November 2009, the Canadian Nuclear Safety Commission (CNSC) renewed Bruce Power's operating licences for 5 years until 2014 and gave permission to refuel units 1 and 2. In May 2014, the CNSC extended the licence to May 2015 and public hearings were scheduled for early 2015 in Ottawa and Kincardine. A new operating licence was granted for 1 June 2015, until 31 May 2020 and was renewed again from 1 October 2018 until 30 September 2028.
In 2023, it was announced that the site could potentially open a third nuclear power station. Bruce C was first proposed in the late 2000s, however it was not proceeded with at the time.
In 2023, the Bruce generating station produced more than 45 TWh of electrical power, about 7% of the total Canadian electricity consumption.
Description
The power plant comprises eight CANDU pressurized heavy-water reactors arranged into two plants (A and B) with four reactors each. Each reactor stands within a reinforced concrete containment. The steam generators are 12 m tall, and weigh 100 tonnes each. Each plant uses three fueling machines, shared between the four reactors, which travel in a duct cut through solid rock beneath the reactors, traversing the entire plant. The duct doubles as part of the pressure relief system, connected to the vacuum building. Each reactor has its own turbine generator set, with one high-pressure turbine and three low-pressure turbines driving one generator. The turbine hall is about 400 m long at each plant and houses the four turbine generator sets. Cooling water is taken from Lake Huron. There is (originally) one control room per 4 reactors.
Bruce A Construction of Bruce A began in 1969, making it the successor to the Pickering A plant. Bruce A units were originally rated at 750 MWe net / 805 MWe gross, which was later increased to 769 MWe net / 825 MWe gross. the Bruce A units were capable of producing up to 779 MWe net according to IESO generator data. Each reactor requires 6240 fuel bundles that weigh 22.5 kg each, or about 140 tonnes of fuel. There are 480 fuel channels per reactor, containing 13 bundles each. There is storage capacity for about 23,000 bundles. Approximately 18 bundles are discharged per reactor per day.
The original Bruce A steam generators utilized a separate large horizontal shared steam drum (with one steam drum common to four steam generators), a design dropped in most other plants at the time. Issues related to the AECL requested design of the tube supports caused repair and delay costs, which exceeded the net worth of the builder Babcock & Wilcox Canada.
Until they were removed in 1998, Bruce A reactors used unique booster rods to control reactivity. Booster rods contained 93% uranium-235, and were inserted to overcome reactor poisoning. Bruce B and all other Ontario Hydro reactors instead use absorber rods called "adjusters" which are normally inserted and are removed to overcome xenon poisoning.
Bruce A demonstrated an "excellent" early operating history. Together with Pickering A, the eight units achieved an overall average capability factor of 83% over the initial five-year period. However, by 2001, when Bruce Power took the lease, all Bruce A units were laid-up.
In 1981, Unit 1 was ranked the top reactor in the world with a 97% availability factor. In December 1997, after about 20 years of operation, it was out of service. In 2005 (after 7 years of being idle) refurbishment started. In September 2012 (15 years out of service) it resumed operation.
In 1982, Unit 2 was temporarily shut down due to a pressure-tube leak. In 1986, a fuel channel failed while the reactor was shut down; some of the fuel elements were swept into the moderator (calandria) and were difficult to remove.
In 1986, maintenance workers accidentally left a protective lead blanket in the steam generator of Unit 2. By the time the mistake was discovered six years later, the blanket had melted, severely damaging the boiler. In October 1995, after about 18 years of operation, unit 2 was taken out of service. In 2005 (after 9 years of being idle) refurbishment started. In October 2012, it resumed operation.
In 1982, Unit 3 set a then world record of 494 days of continuous operation and Bruce A was the most reliable multi-unit station in the world. From April 1998 onward, Bruce A3 remained idle for 6 years, returning to service in January 2004 (at which time the unit was 32 years old). Refurbishment in unit 3 began in March 2023, with the plan being to return to service in 2026. Unit 3 was returned to service on June 8, 2026, 7 months ahead of schedule.
In 1990, a software error in unit 4 caused a fueling-machine error, damaging a fuel channel. In 1993, reactor power was reduced to 60% until various loss-of-coolant accident (LOCA) scenarios could be addressed. Subsequently, Bruce A units returned to 89% of rated power. In March 1998, after about 19 years of operation, unit 4 was taken out of service. It returned to service in October 2003, after 6 years of being idle (at which time the unit was 31 years old). Planned refurbishment of unit 4 to begin in 2025 (when the unit will be 53 years old).
Bruce B Bruce B units, located to the south of Bruce A, are of a slightly larger capacity: 817 MW net, 840 MW gross. which is attributed to an improved steam generator design, where the steam drum is integral to each steam generator in a "light bulb" arrangement, eliminating the horizontal cross-drum. In 1990, a nine-week "impairment" of Bruce B was created when a technician incorrectly set the calibration on radioactivity monitors. In 2007, Bruce B 7 was the top performing nuclear reactor in Ontario with 97.2% performance. and in 2009, Bruce B 5 was first with 95.4% performance.
Bruce B 5 Construction began 1 June 1978. On 15 November 1984 it reached first criticality. Commercial operation began on 1 March 1985. Originally scheduled to be shut down in 2016 (unit would have been 31 years old). Planned refurbishment to begin in 2026 (unit will be 41 years old). Bruce B 6 Construction began 1 January 1978. On 29 May 1984 it reached first criticality. Commercial operation began on 14 September 1984. Originally scheduled to be shut down in 2018 (unit would have been 34 years old). Refurbishment began in January 2020 (unit was 36 years old). Return to service took place on September 14, 2023. Bruce B 7 Construction began 1 May 1979. On 7 January 1986 it reached first criticality. Commercial operation began on 10 April 1986. Originally scheduled to be shut down in 2015 (unit would have been 29 years old). Planned refurbishment to begin in 2028 (unit will be 42 years old). Bruce B 8 Construction began 1 August 1979. On 15 February 1987 it reached first criticality. Commercial operation began on 22 May 1987. Originally scheduled to be shut down in 2019 (unit would have been 32 years old). Planned refurbishment to begin in 2030 (unit will be 43 years old).
Electrical output The graph represents the annual electricity generation at the site (A and B combined) in GWh. In 2023, it was about 28% of Ontario's production.
As of the end of 2025, the total lifetime output of the facility was 1,692,499 GWh.
Notable Achievements In 2009 total site output hit 1,002 TWh, making it the first nuclear power plant in the world to produce 1 PWh (1,000 TWh). Gravelines in France achieved the same in 2010.
As of the end of 2020, the 8 Bruce units had produced a combined total of 1,479.59 TWh.
After Units 1–2 completed refurbishment activities and were brought back online in 2012, Bruce became the largest operating nuclear generation facility in the world by both the number of currently operational reactors and total net output capacity, having a total of 8 operational CANDU nuclear reactors with a combined output of 6,384 MWe net (7,276 MWe gross) when all units are online, surpassed now by two South-Korean plants: Kori NPP since 2019 and Hanul NPP since 2022. The Kashiwazaki-Kariwa Nuclear Power Plant in Japan had a larger total output capacity, but it has been out of service since 2011.
Transmission Lines As of 2008, the Bruce station had three double-circuit 500 kV transmission lines to feed the major load centres in southern Ontario, in addition to three double-circuit 230 kV lines serving the local area. These circuits are connected via two high voltage switchyards owned and operated by Hydro One.
In 2006, OPA had proposed increasing transmission line capacity, at a cost of between $200–600 million, described as "the largest electricity transmission investment in Ontario in the last 20 years". The line was completed in June 2012, several months ahead of schedule, with over 700 towers built for the 180 kilometre line to Milton. The project ranked 45th in Renew Canada's annual list.
Comparison with Pickering Compared to the other major Canadian nuclear power plant built earlier, Pickering station, the Bruce reactors have higher power output, achieved by: increasing the number of fuel channels, increasing the number of bundles per channel, and a change in the fuel bundle itself.
At Bruce, the fuelling equipment is shared by the four reactors of each plant, while at Pickering each reactor had a fuelling machine. The Bruce fuelling machine and fuel channel end fitting design (mostly by Canadian General Electric) is based on the Nuclear Power Demonstration design. The Pickering design by AECL was based on Douglas Point.
The building design of the reactor differs: Bruce uses a squarish "close-in" design, in which as much of the equipment as possible is arranged outside the main containment envelope for easier access during maintenance and emergencies. The steam generators penetrate the containment. The primary coolant pumps and primary piping systems are inside the containment enclosure, but the pump motors are outside containment and the drive shaft seals form the containment boundary. Pickering has round domes which enclose much of the secondary cooling equipment. The Pickering A system did not originally have a second independent shutdown system. The Bruce containment concept differs: the reactor's reactivity mechanism deck serves as a part of the containment boundary, is closer to the reactor, and more prone to damage in the event of an accident ("accidental physical disassembly"). The designers therefore foresaw the need for a second safety system to reduce the risk of an accident. Bruce received a second, fully independent Safety Shutdown System (SDS2) which uses a liquid neutron poison injection method. The Bruce system also has a high-pressure Emergency Coolant Injection System (ECIS).