Speaking to the Calgary Herald editorial board, Dion acknowledged nuclear is part of the "energy mix" in Canada, but doesn't believe it's a viable option for use in Alberta's oilsands due to lingering concerns about whether its waste can be safely disposed.
"I have no power to stop a province to do that. It's provincial jurisdiction," Dion said.
"I am concerned about the waste and I don't hide my concerns."
The debate over nuclear power in Alberta has heated up in recent months as industry and government look for ways to reduce the use of natural gas and slash greenhouse gas emissions from the Athabasca oilsands - a major contributor to carbon dioxide emissions in Canada.
Enormous amounts of gas are used in the heating and extraction of tar-like bitumen, and oilsands output generates significantly more carbon dioxide than conventional crude production.
A nuclear plant would be used to produce electricity and generate steam that would be pumped underground to help melt the bitumen for easier extraction. However, exact construction costs are unknown - some estimates peg it at $4 billion - and significant technical and political hurdles must be cleared before a nuclear plant in the oilsands could proceed.
Earlier, Husky Energy CEO John Lau said his company is studying nuclear energy for its future oilsands developments in northern Alberta.
But new provincial Environment Minister Rob Renner said he's skeptical about nuclear energy in the oilsands, including concerns over how to dispose of its waste.
"We obviously have no experience with it in Alberta," Renner said. "It's worth looking at, but I think it's a very long-term solution."
Environmental groups also are opposed.
"It's the farthest thing from clean energy. It's pretty much a toxic energy," said Marlo Raynolds, executive director of the Alberta-based Pembina Institute.
Raynolds doubts the economic viability of a nuclear facility and said it could make the oilsands potentially a larger terrorist target.