A federal regulator is allowing the nuclear power plant in Pickering, Ont., to keep operating for another five years.
The Canadian Nuclear Safety Commission has renewed the plant's licence — which was set to expire next month — until the end of August, 2018.
The plant's operator — the Ontario Power Generation — says it intends for the plant's six active reactors to stay operational until 2019 and 2020, when it expects to hit 247,000 full-power hours.
But the federal regulator says the plant can't go beyond 210,000 hours pending a future decision.
The licence extension comes after public hearings earlier this year in Ottawa and Pickering which saw OPG and 136 interveners make submissions.
The plant's first active reactors went online in 1971, and two of those are still in service while another four units have been operating since 1983.
OPG says last year, the Pickering nuclear plant produced 13 per cent of the electricity consumed in the province.
Greenpeace Canada nuclear analyst Shawn-Patrick Stensil said the four newer reactors hit the end of their designated life-span next year.
"This is Canada's oldest nuclear station and it hasn't proven that it can operate these reactors safely beyond their design life," said Mr. Stensil, who appeared at regulatory hearings on the Pickering plant.