Darlington Nuclear Generating Station

Darlington Nuclear Generating Station
Country	Canada
Location	Clarington, Durham Region, Ontario
Coordinates	43°52′22″N 78°43′11″W / 43.87278°N 78.71972°W / 43.87278; -78.71972
Status	Operational
Construction began	Unit 1: April 1, 1982 Unit 2: September 1, 1981 Unit 3: September 1, 1984 Unit 4: July 1, 1985
Commission date	Unit 1: November 14, 1992 Unit 2: October 9, 1990 Unit 3: February 14, 1993 Unit 4: June 14, 1993
Construction cost	$14.4 billion CAD ($26.4 billion in 2023 dollars[1])
Owner	Ontario Power Generation (OPG)
Operator	Ontario Power Generation (OPG)
Employees	3000+
Nuclear power station
Reactors	4
Reactor type	CANDU PHWR
Reactor supplier	AECL
Cooling source	Lake Ontario
Thermal capacity	4 × 2776 MWth
Power generation
Units operational	4 × 878 MWe (NET)
Make and model	4 × CANDU 850
Nameplate capacity	3512 MW
Capacity factor	63.22% (2017) 82.90% (lifetime)
Annual net output	23,562 GWh (2020) 764,192 GWh (lifetime)
External links
Website	Darlington Nuclear
Commons	Related media on Commons
[edit on Wikidata]

Darlington Nuclear Generating Station is a Canadian nuclear power station located on the north shore of Lake Ontario in Clarington, Ontario. It is a large nuclear facility comprising four CANDU nuclear reactors with a total output of 3,512 MWe when all units are online, providing about 20 percent of Ontario's electricity needs, enough to serve a city of two million people.^[5] The reactor design is significantly more powerful than those used in previous CANDU sites at Pickering and Bruce, making its 4-unit plant the second-largest in Canada behind the 8-unit Bruce. It is named for the Township of Darlington, the name of the municipality in which it is located, which is now part of the amalgamated Municipality of Clarington.

The plant began construction in September 1981 and planned to start initial operations in 1985. Several delays ensued, and the construction start on Units 3 and 4 was put off until 1984 and 1985. Unit 2 entered operation in 1990, followed by Unit 1 in 1992, and Units 3 and 4 in 1993. The delays and resulting cost overruns have made Darlington a primary case study for the anti-nuclear movement in Canada, and was one of the main reasons Ontario Hydro was broken up in 1999 and its debts paid off by special billings. After initial operations and shakeout, it is often among the most reliable plants in the world in terms of capacity factor. As of 2023^[update], the plant is undergoing a mid-life upgrade, with two units completed and the second two expected to complete in 2026.

Room for a second four-reactor unit had been in place since the original site selection, with a large area to the east of the current plant set aside for what was known as Darlington B. In 2006, Ontario Power Generation began the process of applying to build a two-unit plant on the B site. This project was cancelled in 2013 when the estimated cost was far beyond initial projections. In 2020 plans started to install a much smaller BWRX-300 small modular reactor on the B site, which are ongoing as of 2023^[update].