There are designs which avoid meltdowns, yes. Because the fuel is already molten. Like FliBe. It has a safety plug which if melts, the fuel flows in a contained

There are designs which avoid meltdowns, yes. Because the fuel is already molten. Like FliBe. It has a safety plug which if melts, the fuel flows in a contained reservoir and solidifies. https://en.m.wikipedia.org/wiki/FLiBe https://en.m.wikipedia.org/wiki/FLiBe