Club409

drew you need to start working with washed-up action heroes or at least start enforcing the law by any means necessary

Um..What?

http://money.cnn.com/2011/03/28/autos/vw_jetta_horn_recall/index.htm?hpt=T2

Thorium reactors aren't necessarily good or bad they have pros and cons just like most other designs. A lot of people make claims about Thorium reactors that make them sound awesome but most of the advantages are equally valid for a number of `next generation' reactors not just Thorium-fueled reactors.  

It is frequently claimed that Thorium reactors are passively safe (a vague term that usually means in an emergency/accident situation the reactor will shut itself down without operator intervention and won't melt even if all of the coolant is lost) and can never suffer a meltdown because of its higher melting point.  Most (all?) Gen IV reactors are designed to have some level of passive safety built in so within the next couple of decades we should have reactors that are passively safe with or without Thorium.  I don't agree that a meltdown couldn't happen although it might be slightly less likely depending on the design.  Declaring a meltdown impossible just sounds like an invitation for Murphy's law to prove itself.

Another advantage that gets cited is that Thorium reactors are proliferation resistent because they don't produce Plutonium in large quantities and the fissile material that they do produce (Uranium-233) is more difficult to handle than say Plutonium.  I don't consider this a major issue because I think the proliferation risk of standard fuels is grossly overstated.  In order to take spent nuclear fuel and make a weapon you need a facility that can chemically separate Plutonium from Uranium and assorted other transuranic elements then you have to separate out the Plutonium-239 (good for weapons) or at least remove nearly all the Plutonium-241 (bad for weapons).  It would be easier (IMHO) to start from natural Uranium and simply enrich it to get weapons grade Uranium (what Iran is doing).

Next on the list is cost.  Thorium is more abundant than Uranium so the logic is that it will be cheaper.  Most of the cost of operating a nuclear reactor is not the fuel and Uranium is still fairly cheap and we really have enough to last quite a long time (and much longer still if we would reprocess spent fuel) so I don't consider this a major selling point.  India is interested in Thorium reactors for this reason because they have huge Thorium reserves but very little Uranium.

One issue with Thorium is that it isn't fissile meaning that it can't start or sustain a chain reaction on its own.  In order to operate a Thorium reactor you have to provide some amount of material to get the reaction started (either U-235 or Pu-239).  Once a chain reaction is going Thorium absorbs neutrons and produces U-233 which is fissile and allows the reactor to continue operating.  The next issue is simply that it's a completely untested technology and issues are nearly guaranteed to arise if and when it is tested.  This isn't a defect of Thorium reactors per se but will prevent them from being used commercially for a very long time (the same is true of almost any advanced reactor design).  Finally Thorium fuel is much more difficult/expensive to reprocess because it tends to be more highly radioactive in the short term.  This isn't an issue based on our current plan of not reprocessing any fuel in the US but I think eventually we should start and then it becomes an issue.

In summary there is some good and some bad but it's just not a miracle cure for all problems.

In the long run I think you'll find that educating the internet is a much more rewarding and worthwhile experience

cool!  what interesting thing did you say?