My concern about nuclear is the issue of whether they can be safely operated in a world that is falling apart for other reasons--a financial system that is breaking; a system that provides too low a price for oil, natural gas, coal, and electricity.
In such a system, safeguards that we have been used to, including the availability of electricity going into a nuclear power plant may be lacking. The ability to pay workers may disappear. The ability to keep electrical transmission lines repaired is likely to decline over time, making electricity from nuclear less and less useful. The ability to decommission such plants will disappear, cleating a much higher hazard for nuclear waste problems. These plants have only a 60 year or so lifetime. They require fossil fuels to build, so it is unlikely that we can build replacements.
Thorium reactors aren't really ready for prime time yet. I cannot imagine one being built in this country, without the process being tested more and perfected. The low cost idea is only in theory, until production can really be put in place.
Another issue is timing. We have a world of financial woes right now. We need a solution right now--not five or ten years from now.
A related issue is cost. Ramping up nuclear would take huge investment right now, at a cost that countries could not afford. You may think nuclear is cheap, but it depends on the amount of safety controls built in. The cost is quite high in the US. It is likely quite a bit lower is less saftety conscious parts of the world.