I'm still not a fan of Nuclear power, however, I do understand it's current appeal. Yes, at the site of the plant, virtually no carbon is emitted. But this doesn't take into account mining and processing activities.
Safety
I fully understand that, like most accidents in the world, the majority of nuclear accidents were caused by human error. Unfortunately, humans aren't going to be cut out of the picture anytime soon. While extremely unlikely, the cost of failure at a nuclear facility is simply too high, and with every new reactor that is in operation the risk, however small, grows.
Waste
As much as government and industry wish to whitewash this issue, it remains unresolved. The fact remains that the world has a growing stockpile of material which requires careful storage and monitoring for hundreds of thousands of years. Most of the material is currently at temporary facilities and will have to be handled and moved at minimum to a permanent facility. I find that in most discussions of Nuclear power, almost nobody wants to talk about the ongoing cost of maintaining and storing the byproducts and anybody who expects industry to pick up that tab indefinitely is out of their mind. None of this cost is calculated into the cost of price of electricity generated. No, it will be dumped on government in the form of cleanups and public debt. Anyone who doubts this simply has to look at amount of cleanup the government is currently responsible for from industry long since moved on. Who's paying to build the current long term site? Which brings us to the concept of a permanent facility. I know /. is populated by lots of engineers who love nothing better than to undertake new technological challenges, however, a million years is too long of a timescale. This puts you in the realm of unforeseen earthquakes and meteor strikes and a host of 1 in 1 000 000 year events. Frankly, I find it unconscionable that we are willing dump such a tremendous problem in the laps of our children, especially when there is no guarantee that they will be in any position to actually fix any problems that might occur. Then there is that whole can of worms known as reprocessing, with the associated geopolitical implications.
unanswered questions
Finally, there remains one great unanswered question: Why do we need more nuclear power? I know why industry wants it. I know why government wants it. But why do we need it? I can see some limited small scale usage for medicine and perhaps deep space probes, but for our everyday needs Solar and wind ARE sufficient to take care of our energy needs, and when you consider that they are just at the beginning stages of their development they will only get better. Imagine how much better they would be if renewables actually had the same level of investment that the nuclear industry has been (and still is gifted with)? When you throw in geothermal, hydro, biomass, and some limited conventional generation it becomes very difficult to justify the risks and burdens of large scale nuclear deployment.