Nuclear power plants have been producing commercial electricity in Canada since the early 1960s. The CANDU reactor is a distinctly Canadian innovation. CANDU stands for Canada deuterium uranium, because it uses deuterium oxide (heavy water) as a moderator and coolant and uses natural (not enriched) uranium as a fuel. CANDU reactors can be refuelled while operating at full power whereas most nuclear reactors must be shut down for refuelling.

CANDU technology has been employed in reactors in Argentina, China, India, Pakistan, Romania and South Korea. There are 34 CANDU reactors globally, 30 of which are operable.

In Canada, there are 19 operable CANDU reactors at four nuclear generating stations. The Bruce Nuclear Generating Station, on the shore of Lake Huron, is the largest operating nuclear power facility in the world based on its eight reactors. It first delivered power to the grid in 1976. The Darlington nuclear generating station is Canada’s second-largest nuclear facility by total energy output. The Pickering Nuclear Generating Station is Ontario’s smallest commercial nuclear facility. Despite its smaller size, the Pickering station powers up to 2.5 million households.

Point Lepreau was the first CANDU 6 reactor to be licensed for operation, the first to achieve criticality and first to begin commercial operation. This one nuclear reactor supplies almost one-third of the entire province’s electricity!