Bruce Nuclear Generating Station

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. As of 2017 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 as of 1984 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 MW_e net (7,276 MW_e 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).
• Each Bruce "4 pack" has its own Vacuum Building, while Pickering has one per eight reactors.
• At Pickering, the vacuum duct was closed by nonreturn valves, to prevent flow of the steam/air mixture from the duct to a non-accident reactor unit following a LOCA. In the Bruce concept, there is no such non-return valve; the reactor buildings are all interconnected during normal operation.
• Bruce uses single-circuit heat transport system, while Pickering had two circuits.
• The first two reactor units of Pickering A originally used Zircaloy-2 pressure tubes. All subsequent CANDU units use a zirconium – 2.5% niobium alloy.
• Bruce uses a pressurizer to maintain coolant pressure, Pickering a different system.
• The Pickering design utilized 12 small steam generators operated in groups of three which can be individually valved out of the heat transport loop, as can the 16 pumps per reactor, with 4 being spare. At Bruce, the number of steam generators and coolant pumps was reduced to 8 and 4 respectively, without any spare pumps, thereby simplifying the piping. The Bruce system permits reactor power level to be adjusted more quickly and easily.

Construction costs

Bruce A was projected to cost CA$0.9 billion in 1969. Actual cost was $1.8 billion (in 1979 dollars). Adjusted for inflation, the $930 million estimate in 1979 dollars is $1.88 billion, putting Bruce A under budget.

Bruce B was projected to cost $3.929 billion in 1976. Actual cost was $5.994 billion (in 1987 dollars). Adjusted for inflation, the $3.929 billion estimate in 1987 dollars is $8.667 billion, putting Bruce B under budget.

Cost of generated electricity

In 2010, Bruce Power was paid approximately $60 million for contracted, but unused power.

On 1 January 2016, Bruce Power began receiving a single contracted price for all output from the site of CA$65.73 per megawatt-hour (MWh). This price is partially adjusted annually to account for inflation and wage growth, with additional monthly fuel cost adjustments, and it includes a small payment for Bruce's unique ability to curtail up to 2400 MW of generation (total across all eight units – up to 300 MW per individual unit) via steam bypass operation during periods of surplus generation.

During the course of the refurbishment of Units 3–6, the price will be raised in steps to cover individual reactor refurbishment costs, with each increase starting 12 months prior to the start of each individual refurbishment. Each increase will last only until that unit's refurbishment costs, which are fixed prior to refurbishment start, have been recovered. The average price per MWh that will be paid to Bruce Power for all electricity generated from 2016 to 2064 (covering the entire refurbishment period for Units 3–6 plus the entire expected remaining post-refurbishment lifetimes of all eight Bruce Power reactors (including the two that were already refurbished) was estimated to be approximately CA$80.6/MWh in 2017 dollars by the Financial Accountability Office of Ontario. In contrast, the estimated average price of nuclear electricity from all three Ontario nuclear plants during that same 2016–2064 period was estimated to be CA$80.7/MWh in 2017 dollars, the 2017–2018 unit cost of Ontario nuclear power was CA$69/MWh, and the current price of electricity for "most residential and small business customers" was CA$114.9/MWh (prior to the Fair Hydro Plan) or CA$97.6 (after the Fair Hydro Plan).

Blackout of 2003

During the Northeast Blackout of 2003 three Bruce B units continued running at 60% reactor power and 0% grid electrical power. They were able to do so for hours, because they had steam bypass systems designed to de-couple the reactor output from the generator electrical output. The three units were reconnected to the grid within 5 hours. Bruce A and B stations were designed to operate indefinitely while disconnected from the grid.

"Contrary to popular belief, the electrical generators of nuclear plants can follow the load demands of the electrical grid provided specific engineered systems to permit this mode of operation are included in the plant design."

Cobalt-60 production

Cobalt-60 (⁶⁰Co) can be produced in a CANDU reactor by using adjuster rods made primarily out of ⁵⁹Co (instead of the normal stainless steel), which is slowly transmuted into ⁶⁰Co via neutron activation (⁵⁹Co + n → ⁶⁰Co). These now-intensely-radioactive cobalt-60 adjuster rods are then "harvested" (removed and replaced with fresh ⁵⁹Co adjuster rods) after one to three years of use in the reactor during a routine reactor shutdown, and are later processed into sealed ⁶⁰Co sources of varying intensities by Nordion. The Bruce nuclear power plant has been producing ⁶⁰Co since the 1980s, and almost all of the world's supply of ⁶⁰Co comes from various CANDU nuclear reactors, with Bruce being the single largest supplier. As of 2007, Bruce supplied over 40% of the world's ⁶⁰Co. This rose to over 50% by 2016, with Pickering supplying approximately another 20% of global demand. In 2016, Bruce extended their contract with Nordion for the continued supply of ⁶⁰Co to cover the entire projected post-refurbishment life of the Bruce reactors, which are expected to operate until 2064.

Bruce also began producing High Specific Activity (HSA) ⁶⁰Co in 2016, which is designed for highly specialized medical uses such as cancer treatment and had been primarily produced at the NRU reactor for the past 60+ years (which was originally scheduled to be shut down in 2016, but will be kept online until 31 March 2018 due to the general worldwide lack of sufficient replacement medical isotope production capacity for several critical isotopes such as molybdenum-99). As the NRU produces over two-thirds of the world's HSA ⁶⁰Co, Bruce's ability to supply HSA ⁶⁰Co will become critical to help fill the immense production gap left by the NRU once it is decommissioned in 2018. OPG and Bruce Power are collaborating on an effort to expand ⁶⁰Co production to the Bruce A and Darlington reactors in order to fully cover Pickering's production (which will end when the plant is decommissioned in 2024) in addition to the inevitable gaps in ⁶⁰Co production capacity that will be caused by the upcoming refurbishments of six of Bruce's reactors (Units A 3–4 & Units B 5–8), as well as all four of Darlington's reactors. They are also working on expanding the production of HSA ⁶⁰Co to more reactors.

In 2017, Bruce Power became the first Canadian recipient of a Top Innovative Practice (TIP) award from the Nuclear Energy Institute (NEI) for its ongoing work with Nordion to produce cobalt-60.

Radioisotope production project

Bruce Power is working with Framatome to develop the capability to "produce shorter half-life radioisotopes (such as molybdenum-99, lutetium-177 and iridium-192)" using Areva's proprietary technology for the on-line production of radioisotopes in heavy water reactors. Areva will design and supply the system for installation in the existing Bruce units.

In June 2018, Bruce Power and ITG (a subsidiary of Isotopen Technologien München (ITM)) announced the start of a joint effort to explore producing lutetium-177 in Bruce's reactors, with ITG planned to manage the development, processing, and distribution of lutetium-177. The initial Isotope Production System (IPS), producing Lu-177, came online in January 2022.