Pros/Cons of Thorium based reactors?

YES!

This is one of the biggest, best, most-overlooked quick solutions to the global warming crisis.

1. Compared to conventional light-water reactors, thorium fluoride reactors produce 0.1% of the waste. And the waste that is produced has a half-life of only 30 years, compared to 10,000 years or so with waste produced by light-water reactors.

2. Fuel is Thorium, which, though radioactive, is the least radioactive substance known -- about 1000 x less radioactive than Uranium. Easy to transport safely, minimal shielding required, safe to mine. Also four times more abundant that Uranium.

3. Unlike conventional light-water reactors, thorium fluoride reactors can't melt down, because the fuel is already liquid in the reactor core.

4. Unlike conventional light-water reactors, the core liquid in thorium fluoride reactors is unpressurized, meaning much less chance of leakage, and zero chance of pressure explosion. Also easier to engineer and build.

5. You can actually use a thorium fluoride reactor to "cook" existing radioactive wastes from light-water reactors, turning it into usable energy.

6. The reactor can be designed to be self-regulating -- no control rods, no operator input required. When the load is too small, less heat is removed through the heat exchanger, causing more heat to be build up in the core. At that point, the hotter liquid fuel expands out of the reactor core, reducing the reaction. In times of greater load, the reverse process happens.

7. Although it's possible to build a bomb from U233, the fissile isotope in a thorium reactor, it's not easy to do so -- the gamma radiation is much higher than with U235, making material handling much more difficult. So there is less chance of weapons diversion. Further, if you size the reactor properly (make it small enough), the amount of "excess" U233, not needed to sustain the reaction, is small.

We actually built one of these back in the 1960's, so the technology is proven. But there would still be a lot of original engineering involved in bringing this technology back. Given their manifest advantages, this is a HUGE win-win technology that should be pursued vigorously.

Thorium Based Reactors

Thorium based reactors in terms of economics are unlikely to be all that much different to uranium based reactors (although they won't be competing for whatever uranium is being mined). Nuclear power in general is probably the quickest and most cost effective solution to global warming and thorium is one of the fuels that can (and probably will, India has a lot of thorium but not much uranium) be used in nuclear reactors.

Conventional LWRs can't use thorium although it is possible to make a Light Water Breeder reactor that uses it (Shippingport was one) and the CANDU design should be able to cope with thorium as well.

Thorium isn't fissile (but fertile, Th232 is bred into U233) so you'll need some fissiles to start the process along but a Thorium reactor will only need a single load of Uranium from the ground to start that process.

Also many of the advantages that you'll see listed over Uranium also apply to the Plutonium breeder cycle (and Molten Salt Reactors are capable of doing that as well).

"Is there any reason AGW doubters would object to this technology being promoted, even if they don't see the need to curtail CO2 emissions?"

The ones that have financial interests in fossil fuel energy will have a reason to object to it.

The ones who think that AGW is just a ploy to promote nuclear energy will also object to it.

But I suspect that most denialists wouldn't have any problem with thorium reactors (in fact there's some evidence that the type of people who tend to deny global warming are actually less likely to do so if nuclear is proposed as the solution to global warming instead of a reduction in standard of living).

Ken we might doubt for good reasons the claims promoting AGW. The majority of those who doubt are fully in favor of a technological solution to the energy problem. It has been the adherents of AGW that have for more than 30 years now fought against practical solutions like nuclear and fast breeders, we love the idea because it will cripple big oils ability to control things.

With the right technology we can solve any problem and that asteroid being tracked to pass close by in a few years could be manufacturing materials instead of a planetary danger if it hand not been for Jimmy Carter and the democrats in Congress that killed SDI and drove a maple stake into its heart.

Thorium is cheaper, but its difficult to start the fission in it. Because of this in older nuclear power plants uranium was used as that time they didn't know how to use it. To use Thorium it is again used again with Plutonium or Uranium for initializing and sustainably of the reaction.

This technological challenge, copied from the wiki entry, ought to be flashing, highlighted, and lit up in searchlights:

Uncooled graphite moderators can cause some geometries of this reactor to increase in reactivity with higher temperatures (positive void coefficient), making such designs unsafe. Careful design may fix this, however.

It is probably worth noting that the Chernobyl-4 reactor was also a positive void coefficient design. More careful design *may* fix that however. May.

After reading on it somewhat, I think its a a great idea however an Idea is of no use unless someone has the courage to implement it. I say lets do it, I am skeptic on global warming not alternative energy.

I'm not nearly as knowledgeable as you or Mr. partial-diff, but I'm a "doubter" and have nothing against ANY type of nuclear reactor - so long as it's shielded. :)

Sounds great to me!

At least you didn't use (deniers), why would anyone object to alternative energy? Other then a stuck in the mud Democratic Congress.