Click on the image above for a virtual tour of OPG's Darlington Nuclear Generating Station.
The Darlington Nuclear Generating Station is Ontario Power Generation's newest CANDU (CANadian Deuterium Uranium) nuclear generating station. It is a 4-unit station with a total output of 3,512 megawatts (MW) and is located in the Municipality of Clarington in Durham Region, 70 km east of Toronto.
It provides about 20 per cent of Ontario's electricity needs, enough to serve a city of two million people.
Darlington produces electricity with heat created by nuclear fission using natural uranium fuel. The heat produced by this reaction is transferred, via a separate heavy water heat transport system to boilers where ordinary water is boiled and the resulting steam is used to drive a turbine generator that produces electricity. This electricity is fed into transmission lines that carry the power from the site to residential, commercial and industrial users.
Public and employee safety is the most important consideration when operating an Ontario Power Generation nuclear facility. Like our other nuclear power generating stations, Darlington has been designed and built with multiple barriers to safeguard against the release of radioactive materials. These barriers are protected by careful plant operation and maintenance, regular testing and inspection by our highly qualified staff.
The Darlington station is licensed by the Canadian Nuclear Safety Commission which regulates the use of nuclear energy and materials to protect health, safety, security and the environment through the Nuclear Safety and Control Act. In addition, the station is subject to other federal and provincial government safety and environmental regulations such as the Environmental Protection Act and the Planning Act. Darlington meets or surpasses all the prescribed regulations.
These four structures are made of heavily reinforced concrete (external walls 1.8 m or 6 ft. thick) to enclose the reactors and related equipment. Interior concrete walls also shield personnel from radiation during operation. Each building contains one reactor and four steam generators (boilers). The reactor consists of a large, heavily shielded vessel or calandria which contains 480 fuel channels and 6,240 bundles of uranium fuel that are encased in zircalloy sheathing.
This 71 m (240 ft.) high cylindrical concrete structure is connected to the reactor buildings by a pressure relief duct and is a unique safety feature of the CANDU system. The vacuum building is maintained at negative atmospheric pressure. Any release of radioactive steam from the pressurized systems would be sucked into the vacuum building, thus preventing its release outside the station.
This structure houses the turbine hall, shown on the right. It measures approximately 580m (1,900 ft.) long by 137 m (460 ft.) wide by 45 m (145 ft.) high, a space that's approximately 6 football fields long, and twelve storeys high.
Irradiated Fuel Bays
Two water-filled pools inside the station store the irradiated fuel once it's removed from the reactors. The pools keep the fuel cool and shield station workers from radiation. Eventually the used fuel will be moved to dry storage containers.
Tritium Removal Facility
Tritium is a by-product of the nuclear reaction and it gradually builds up in Ontario Power Generation's (OPG) reactors. To help keep workers safe, and to minimize the amount of tritium going into the environment, a tritium removal facility was opened at the Darlington site in 1990. This plant extracts tritium from heavy water used in OPG's nuclear reactors. The tritium is safely stored in stainless steel containers within a concrete vault.
Our Commitment to the Future
Darlington, along with OPG's other generating facilities, plays an important role in keeping Ontario running. It also plays a vital role in keeping our air clean, and will continue to produce large quantities of electricity with no smog producing emissions. In fact, Darlington has already made industrial history by becoming the first nuclear station in North America to be certified under the tough ISO 14001 environmental standard.
In early 2013, OPG received three important decisions from the Canadian Nuclear Safety Commission:
- Darlington Refurbishment Environmental Assessment
- Darlington Licence Renewal
- Darlington Waste Management Facility Licence Renewal
Find out how each of our nuclear stations performed in the fourth quarter of 2012.
Find out more about all the ways Darlington Nuclear is making a difference in your community.
Learn more about the Darlington Refurbishment Project.
Download our Darlington station brochure.
Read about the successful Darlington Vacuum Building Outage.