Thorium

In the wake of the Fukushima Dai-ichi Plant Nuclear Disaster, the question in the US is what this event will do to the ongoing debate over nuclear energy. Will it swing public opinion from "pro" to "con" (early surveys suggest it will, at least in the short-term). However, the Obama Administration is continuing to promote nuclear power as a clean and carbon neutral alternative to fossil fuels. We need to watch how the Administration and the Congress provide incentives for next generation nuclear technologies, such as Small Modular Reactors or SMRs. I'm also interested in the potential development of alternative fuel cycles to uranium, namely thorium, which is more abundant than uranium, present in large quantities in the U.S. and more difficult to use as a means to develop a nuclear weapons program. What's wrong with throrium?