The NewNuclearDebate has arised recently from within the environmental movement, largely, it seems, due to the intervention of JamesLovelock.
Over the years NuclearPower has suffered the brunt of the EnvironmentalMovements displeasure, as a result of NuclearFissions well known environmental problems. However, despite this NuclearFission has been used highly successfully in many parts of the world (more than 50% of France's electricity is generating in this way), and has one huge advantage over most of the other generating technologies: it produces no GreenhouseGases.
It is the absence of GreenhouseGases, which has led JamesLovelock to suggest that the EnvironmentalMovement should reconsider the use of NuclearPower. The argument goes is that any Pollution from NuclearFuel has to be less of a problem than that caused by CarbonFuels. Moreover, JamesLovelock argues, the Earth's EcoSystem is at a crux; if we do not control the produce of CarbonDioxide now, climate change will enter into an PositiveFeedBack situation, and will shift to a considerably hotter future. It is this that is the key problem. All technology takes time to develop and the Renewable EnergySources will not be able to provide sufficient power in this key period.
The big difficulty with this argument is that it relies on a lot of quantative measurements, where these measurements are extremely hard to come by.
So, it is certainly true that new technology takes a long time to develop, implement and scale up. However, this will happen quicker if there is an immediate imperative, as for instance, provided by the Kyoto agreement, requiring the reduction in CarbonDioxide production. The heavy use of NuclearPower could reduce the imperative for the generation of better, Renewable, technologies.
Secondly, the use of NuclearPower is by no means a short term solution. Building a NuclearGenerator plant takes a long time; probably at least a decade from inception to production and then will be in use for a long period.
Thirdly, it is not clear whether JamesLovelock's notion that we are on the crux of a PositiveFeedBack situation is true or not. Even if we accept this, exactly how far we are from this is extremely hard to judge.
All three of these factors interact with each other. If the time till we reach PositiveFeedBack is further away, then I think we should not use NuclearPower, as we have the time to develop the Renewables. Similarly, if the development of Renewables happen more quickly than we might predict, then we don't need so much time before PositiveFeedBack.
I suspect that this argument will run and run in the EnvironmentalMovement, because I don't think there is an answer that is in anyway clear. We just don't have the numbers or we only have them with a broad margin of error.