End nuclear with Pickering closure: critics

"The announcement that they're closing Pickering is the first up-front decision to shut down a CANDU reactor because of the bad economics," said Shawn-Patrick Stensil, an energy expert with Greenpeace.

"This is going to have an impact on the federal government's ability to sell AECL because one of the things that was always said is that they'd be able to refurbish old CANDU (reactors) and now we're seeing decisions to shut them down."

A newspaper report suggested that Pickering's nuclear power plant was set to close in a decade due to high cost, while the Darlington nuclear operation was slated for a refurbishment that would extend its lifespan to around 2050.

Neither the government nor Ontario Power Generation would confirm the reports.

A spokesman for Ontario Power Generation said only that the agency had been working on plans for refurbishing Darlington and Pickering B for a number of years, and that further decisions would be coming "soon."

Premier Dalton McGuinty declined to comment until there was a formal announcement, but reaffirmed his province's commitment to nuclear energy.

"Ontarians know that we are making great efforts to shut down our dirty coal-fired generating plants," McGuinty said during an unrelated event in Brockville, Ont.

"We've got to continue to use nuclear, we can't shut it all down — that would be irresponsible," he said.

"It's too important for us when it comes to meeting a baseload of demand."

He also dismissed questions about the rising costs of nuclear, noting the least expensive option would be to just continue burning coal.

"If we could go all green, shut down our coal and our gas and our nuclear... our electricity would go up to a very high rate," McGuinty said.

"And we've got to keep an eye on the overall price of electricity."

Progressive Conservative Leader Tim Hudak, whose party supports nuclear expansion, said it would be irresponsible to shut down Pickering.

"What kind of signal does that send internationally about the companies involved with CANDU, who are trying to bid on products and competitions abroad, when their own Ontario government is undermining what they do?" he said.

The CANDU plants, designed by AECL, are designed to be refurbished at their mid-life point, around 30 years of age.

The government plans to spend $26 billion to maintain nuclear power at 50 per cent of Ontario's supply. But it suspended its purchase of two new CANDU reactors last summer when the cost came in at $20 billion more than initially estimated.