[hga]

To which I say BS, at least for the reason cited.

Sure, the U-232 contaminated U-233 is nasty, but as long as it doesn't make it impractical to make a nuclear warhead it's quantitatively different from the uranium cycle, where after a few months at most plutonium is impossibly contaminated with two even more undesirable isotopes (one is very hot, I've seen estimates of 100kW for a bomb sized quantity (it's used for RTGs in deep space probes), the other precludes much of a bang and required the Manhattan Project to go with an implosion design).

Despite the gamma ray emission drawbacks, it could still be the easiest way to get lots of weapons grade fissionables from civilian power plants.

[fnordfnordfnord]

These folks seem to think the problem is solvable by adding U-238 http://www.coal2nuclear.com/MSR%20-%20Denatured%20-%20CNSLeB...

[hga]

Yeah, that solves it neatly.

Reduces to a protoactinium problem, it decays to U-233 with a half-life of 27 days. The article claims there's so little protoactinium in the total mass of salt and stuff that it's not practical to isolate it, at least not without detection, and failing that, not quickly. This gets into fine details beyond my level of expertise, but I agree the problem is much reduced. Although very possibly still greater than for current LEU designs.