Unit 1 was at 976 days. 2021: On Thursday, February 4 at sometime after 11PM Darlington Unit 1 finally went down for maintenance after 1,106 continuous days of generation, setting the world nuclear operation record and world thermal plant generation record. Spill In 2009, more than 200,000 litres of water containing trace amounts of tritium and hydrazine spilled into Lake Ontario after workers accidentally filled the wrong tank with tritiated water. However the level of the isotope in the lake was less than 1 percent of the regulatory limit and consistent with normal operational activities. See also List of largest power stations in Canada List of nuclear reactors in Canada Nuclear power in Canada Pickering Nuclear Generating Station Bruce Nuclear Generating Station Point Lepreau Nuclear Generating Station References External links Ontario Power Generation Web site Darlington New Build Web Site Nuclear power stations with proposed reactors Nuclear power stations in Ontario Nuclear power stations using CANDU reactors Ontario Power Generation Buildings and structures in Clarington Energy infrastructure completed in 1990