For sale: some of the world's biggest nuclear reactors, in Canada's most populous province, to an experienced owner willing to learn new skills. Ontario Power Generation, a spin-off of Ontario's debt-laden public electrical utility, said on Tuesday it was once again looking for investors to buy some or all of its three nuclear power complexes, with their 20 Canadian Deuterium Uranium (CANDU) reactors, as it attempts to meet guidelines set out for ontario's deregulating electricity market.