> if we’re deploying thousands of nuclear reactors globally, they need to be meltdown-proof. Fusion is the only way to guarantee that. Regulation also isn’t as bad.
MSRs can melt down, but the steps to get there are rarer. Also the number of things that can go wrong and release radioactivity might be higher than LWRs.
Might be, but probably aren't. The most troublesome fission products all end up chemically bound in the fuel salt, and most designs are passively safe, and inherently pretty stable since the reaction slows down significantly as the fuel heats. There's a good safety margin since the salt is liquid over a wide range.
A "melt down" isn't exactly a thing for them since the fuel is melted already by design, but if the fuel manages to overheat, then a plug melts and either the fuel dumps into cooling tanks, or neutron poisons spread through the fuel.