There are a lot of technical problems related to online processing of the fuel, the reactivity of salts at high temperatures with metals, etc.<p>It's a matter of research and development, it can be done, if we devote enough resources to get across the finish line.
Wasn't that right around the time of Fukushima? <a href="https://en.wikipedia.org/wiki/Fukushima_nuclear_disaster" rel="nofollow noreferrer">https://en.wikipedia.org/wiki/Fukushima_nuclear_disaster</a>