daffy country-on-a-ship plans
Or China.
Greenies don't actually trump everything, everywhere.
WAMSR is a paper reactor. It has all the problems of any molten salt reactor, plus a few new ones thrown in for good measure.
It requires fuel channels made of unobtainium. We can't actually make unobtainium so we use Hastealloy instead which cracks at some rate faster than anticipated plant life, as found in ORNL's MSRE. Neutron flux embitterment is also an issue for fuel channels and the long term effect of this is not perfectly understood. WAMSR actually runs at slightly higher temperatures than MSRE which will not improve the cracking problems due to even greater temperature gradients. Transatomic speculates about using certain exotic ceramics to solve this, and that could pan out; materials science does actually solve problems from time to time, but this one hasn't been solved yet.
The reactor produces relatively large quantities of tritium (~12y half life) requiring active separation and storage of the gas. It's effectively impossible to capture all the tritium (hydrogen is slippery stuff), however enough could be retained to bring it in line with conventional reactors, they claim. This assumes the capture system works, is maintained and doesn't leak. Good luck with that. Amusingly the Transatomic Power Technical White Paper claims the addition of Lithium-7 can reduce tritium generation, and you can read about it in section 2.6.4, which doesn't actually exist ...... hopefully the ~$2 million funding injection will get that written. Tritium is among the larger spikes being driven through the heart of Entergy's Vermont Yankee right now, in case one wonders how much this might matter.
As with all MSR designs, fuel must be reprocessed on-site concurrent with reactor operation. This is always offered as a nonproliferation benefit of MSRs. Unfortunately handling molten reactor fuel is a difficult mechanical and chemical process that has never actually been fully modeled in an experimental reactor and would probably be a source of the usual drama inherent in chemical processing operations; leaks, fires and whatnot. Personally I believe this to be the biggest risk involved with MSR reactors; any failure mode that leads to uncontained fuel will produce a lethal radiation flux, fires lofting clouds of radionucleotides and other fun stuff. Bear in mind that every single plant and its resident Homer Simpsons will have to operate their own reprocessing facility for the entire life of the plant; it's not a question of if a mistake will happen, but rather; how heinous are the consequences when it happens. Liquids tend to get away from people.
Finally, WAMSR uses zirconium hydride as the primary neutron moderator, which is pretty novel and a source of some unknowns. The zirconium hydride exists as rods inside the reactor core which also contains the molten fuel and the primary loop coolant water. If, for whatever reason, the zirconium hydride came into contact with the super-heated water in (the inevitable) presence of oxygen, huge quantities of explosive molecular hydrogen would be produced. This is what blew up the reactor buildings of Fukushima no. 1 and 3. The moderator, fuel and coolant are all in close proximity inside the reactor core, flowing through what appear to be relatively fine tubes. Again, due to the chronic shortage of uncrackable unobtainium, we make vessels and tubing such as these out of various steel alloys which frequently crack and corrode and leak.
So, WAMSR is not without its problems.