Mark Clayton at the Christian Science Monitor looks into it.

This describes my position quite well:

But for those energy experts who have done life-cycle analysis of nuclear power, the big concern is that policymakers may be misled into believing that just because nuclear CO2 emissions are low, the cost of nuclear as an option to address climate change would be a bargain. Better, they say, to take the huge amounts of money needed for nuclear plants and use it to build lower-cost solutions that will displace more coal.

"It’s easy to show that building more reactors makes climate change worse than it should have been," says Amory Lovins, chairman of the Rocky Mountain Institute, an energy think tank in Snowmass, Colo. "That’s because a dollar put into new reactors gives two to 10 times less climate solution for the amount of coal-power displaced than if you had bought cheaper solutions with the same dollars."

That’s just it. The question is not whether nuclear power is "acceptable” or “good” by some subjective standard — economic, moral, or otherwise. It’s not even whether investments in nuclear power could lead to emission reductions. The question is: what is the maximum amount of climate change mitigation we can get for a given dollar of investment? Nuclear fails that test.

Then there’s this:

Environmental groups, too, are well aware of the conundrum surrounding the claim of carbon-free energy. Most of them maintain that nuclear is not the answer to climate change.

But their antinuclear arguments have centered on environmental damage from nuclear waste, potential accidents, and terror threats.

Is that true? I don’t really know. But to the extent it is, I’d like to see a lot more emphasis on the former argument. "What’s the cheapest, fastest way to get what we want?" That way of asking the question bypasses many of the charged moral and historical arguments that have made nuclear power such a divisive issue.