I don't wave anything away. My point is there are not fundamental challenges. Its a large expensive engineering project, but you don't need any miracles. We built a working molten salt reactor with 9m and 30 people and they built it in 4 years and then operated it for 10-15 years in the 60-70s. Not Magic.

> It is a legitimately difficult materials science problem to operate a liquid salt pump loop operating at ~1000K and under high neutron flux.

Depending on your reactor design your not actual pumping fuel salt itself at all. Both leading contenders use a pool type system and not LFTR type system where you have to do substantial pumping, specially not of the fuel salt. Neither system in fact pumps fuel salt that is in neutron flux at all.

Have you actually looked at the real world proposed reactors we are talking about?

> It's also not a super-great explanation that a major accident will just cause the salt to flow into the holding tank. What if the holding tank is full of water? Why would it be full of water? I don't know but the planet is absolutely filthy with water and "the basement is unexpectedly full of water" has happened to almost every building humans have ever built. These are supposed to be installed _entirely_ underground, enhancing the danger of water intrusion.

In the case of IMSR, there is 1 meter nuclear grade concrete then a thick wall of steel, then a meter of a secondary cooling salt buffer, then another thick wall of steel, then the primary reactor vessel that is another massive steel cylinder. There are no opening anywhere except from the top.

That whole thing is in a hole that is topped of heavy steel protection on top and that is in building that is safe from aircraft attack. Even if you would have contact of water with the fuel salt the water would be in contact with the top layer of the fuel salt (far less surface area then fuel tubes), that would would freeze the top layer into a solid layer and shortly after the whole reactor would essentially be one block of salt in a metal concrete box.

These reactors are also not depended on water cooling at all, meaning you can build them in the desert or wherever, you don't need to be close to water in any way shape or form. Also you don't just build these anywhere, there is a citing process that looks at these like that.

Next, there is the point that in liquid salt actually does not produce many of the same hazards as fuel pellets. There are gases inside of the solid fuel pellets that get released. In a molten salt reactor the cesium and iodine are not gases, but rather they are bound in the fuel and will not get released in gas form.

This is one of the primary reasons molten salts were proposed int he first place.

So even if you flood the building and a meteor somehow made a hole in the building and reactor containment, and then you would flood it with water that would somehow show up. And all you would achieve with this is a gigantic pool heater, as a solid block of salt sits in the bottom of a hole and produces some steam (without being a system under pressure) that didn't contain the primary dangerous gases we talk about in the 'nuclear cloud'.

The amount of highly improbable events you have to chain to even achieve any danger outside of the nuclear regulated zone borders on comical. And even then its not even close to what we saw happen in Japan.

> Finally there is still the challenge of continuous processing of the liquid fuel, to remove ash, add fissile materials, and separate gases. Nobody knows how to do this. Nobody has explained what to do with all the radioactive krypton etc.

You don't actually need continuous processing and neither company that proposes to build Molten Salt reactors are proposing that.

So again, have you actually looked at the real world proposed reactors we are talking about? You seem to think all Molten Salt reactors are LFTRs.