[sdurkin]

You're both right.

"The real answer is the R&D costs are not worth it because Uranium is still extreamly cheap."

This answers why the market won't develop the technology on its own. But the government could still sponsor research as they did with uranium fission.

"The short answer is that there are many entrenched interests who are not keen on the idea..."

And this answers why the government would never fund it.

[wtallis]

As soon as the market has to bear the cost of long-term storage of waste, they'll be interested in thorium.

[pjscott]

That "waste" is still perfectly usable fuel. You could extract the plutonium and uranium and use that to make more fuel rods. You could burn it in fast breeder reactors, in a hypothetical future where mined uranium becomes expensive enough to warrant the use of fast breeders. Or you could just ship it to Canada, where they have heavy-water-moderated reactors that can use regular nuclear waste directly as fuel, without any chemical reprocessing.

I keep saying that nuclear waste storage shouldn't be thought of as permanent disposal. It should be thought of as keeping a reserve of nuclear fuel for the future.

[protomyth]

To add, http://en.wikipedia.org/wiki/Nuclear_reprocessing - see the last two paragraphs in history for some problematic decisions.