Thorium US Benefits
"Whats not clear is what, exactly, the U.S. will get from the collaboration"
I saw a couple of mentions of US Thorium stockpiles - China has Th stocks, too mostly from their already lucrative rare earths business. So that's not it - though, if thorium is a salable commodity, it opens the US rare earths market back up.
Otherwise, I think the benefits to the US of a Chinese ThMSR are numerous.
First, there's that if China builds it, it gets built. There's a lot of resistance from the American nuclear industry to MSRs that the DoE may or may not be down with. FLiBe Energy is collaborating with the military to get a critical reactor by 2015 as well - but they're pretty much the only game in town so far as the two-fluid, continuously reprocessed design goes. Letting China in on it seems like insurance; we're working for it, but if China gets there first, the USDoE has a plausible prior claim to the IP that built it. They might just forward the design to American nuclear companies with design approval.
There are clear benefits to the US having a cheap, low pollution nuclear reactor. We get to start subbing in the new, smaller devices at existing nuclear sites; we can start dropping them into the process heat end of coal plants; they are several hundred orders of magnitude less prone to releases of radiation (it's literally impossible for a loss-of-coolant accident to result in an RoR, for example); they produce orders of magnitude less waste (~ 1/100 of that of conventional nuclear); their waste has a much shorter shelf-life (it's tapped in ~300 years, rather than ~250,000). They would be a silver bullet, if not for the stigma that comes with the nuclear moniker.
However, if China has them - well, let's just say the American politic has a jealousy problem. If China - filthy, filthy 2008 Summer Olympics China - is besting us on emissions because of these thorium thingies, well, doggoneit, why don't we have 'em? We invented the derned things!
Further, if successful, it means China's energy fleet will run on non-weaponable nuclear; it would further depress the cost of Chinese rare earths - which would be a boon to both of our economies. It would depress the cost of Chinese electricity, which would boost their economy, and keep their prices low - which keeps ours low.
There are a lot of reasons it's a good thing China's in this game. It indicates bad things about the state of American research politics - but knowing where you stand is awesome.
