Upcoming events
Darlington licence renewal
Ontario Power Generation (OPG) has submitted an application to the Canadian Nuclear Safety Commission (CNSC) to renew the Power Reactor Operating Licence for the Darlington Nuclear Generating Station (DNGS) for a 30-year term. The current licence expires on Nov. 30, 2025.
The CNSC will hold a 2-part public hearing in 2025 to consider the application from OPG.
Hearing details:
- March 26, 2025: To be determined (Nations Capital Region and/or virtually via Zoom)
- June 24 – 26, 2025: To be determined (in the community in the vicinity of the DNGS and/or virtually via Zoom)
OPG has extensive experience operating nuclear stations safely and reliably for more than five decades. The DNGS has proven to be a safe, reliable and important source of energy for the Province of Ontario while meeting the constant growth of energy needs. Currently, the DNGS is undergoing a multi-year refurbishment to safely extend operations.
For more information on the licence renewal process, visit the CNSC webpage at www.cnsc-ccsn.gc.ca or visit our Operating Licences page.
A clean power workhorse
Located in the Municipality of Clarington in Durham Region (70 km east of Toronto), Ontario Power Generation’s (OPG's) Darlington Nuclear Generating Station is a four-unit facility responsible for generating over 20% of Ontario’s electricity needs, which is enough energy to power 2 million homes.
Explore how Darlington is an efficient and valued supplier of energy and employment in Ontario.
Quick station facts
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3512
MW of power generated
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480
fuel channels per reactor
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580
metres is the length of the Turbine Hall (nearly 6 football fields)
0
20
of Ontario’s electricity supply
Our generating station
Darlington and OPG’s commitment to the future
Darlington Nuclear, along with OPG's other generating facilities, keeps Ontario running.
Darlington also plays a vital role in keeping our air clean and supplying large quantities of electricity with no carbon or smog emissions.
Darlington made industrial history by becoming the first nuclear station in North America to be certified under the tough ISO 14001 environmental standard.
Reactor buildings
- Darlington reactor buildings are made of heavily reinforced concrete (external walls 1.8 metres or 6 ft. thick) to enclose the reactors and related equipment and 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 encased in zircaloy sheathing.
Vacuum building
- The vacuum building design is a unique safety feature of CANDU®(CANadian Deuterium Uranium) reactor.
- This 71 metre high cylindrical concrete structure is connected to the reactor buildings by a pressure relief duct.
- Maintained at negative atmospheric pressure, any release of radioactive steam from the pressurized systems is sucked into the vacuum building and condensed, thus preventing its release outside the station.
Turbine hall
This huge structure houses the turbines that the station uses to generate electricity and measures approximately 580 metres long by 137 metres wide by 45 metres high. It’s a space approximately six football fields long and twelve storeys high.
Fuel bays
- These two water-filled storage bays inside the station store the used fuel once it’s been removed from the reactors.
- The bays keep the used fuel bundles cool for at least 10 years. After that, used fuel is moved to dry storage containers.
Tritium removal facility
- In this facility, OPG extracts tritium from heavy water used in OPG's nuclear reactors.
- Tritium is a by-product of the nuclear reaction.
- The extracted tritium is then safely stored in stainless steel containers within a concrete vault.
Welcome to Darlington Nuclear
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