Pickering Goes Live: Canada's Nuclear Age Begins

Canada's Pickering Nuclear Generating Station brought its first unit online on February 25, 1971, inaugurating the nation's commercial nuclear power era on the shore of Lake Ontario, roughly 30 kilometers east of downtown Toronto. The station used CANDU reactors, a Canadian-designed pressurized heavy water system that ran on natural uranium fuel without the expensive enrichment process required by American and European reactor designs. This engineering advantage gave Canada a distinct competitive position in the global nuclear market: countries that lacked enrichment infrastructure could operate CANDU plants independently, making the technology attractive to India, South Korea, Argentina, and Romania. Pickering eventually grew to eight reactors with a combined capacity exceeding 4,000 megawatts, enough to power roughly two million homes and making it one of the largest nuclear generating stations in the world at its peak. The plant also became a persistent flashpoint for environmental and safety debate. Its proximity to Canada's largest metropolitan area raised questions that never fully went away, particularly after the Three Mile Island accident in 1979 and Chernobyl in 1986 sharpened public anxiety about nuclear risk. The station's thermal discharge into Lake Ontario drew sustained criticism from fisheries scientists who documented changes to local aquatic ecosystems near the cooling water outlets. Despite these controversies, Pickering operated for more than fifty years before Ontario Power Generation began the decommissioning process, having generated more electricity than virtually any other nuclear facility in Canadian history.