Thorium is also considered to be the fuel candidate for the safest form of nuclear reactor. From Wikipedia https://en.wikipedia.org/wiki/Thorium-based_nuclear_

Thorium is also considered to be the fuel candidate for the safest form of nuclear reactor. From Wikipedia https://en.wikipedia.org/wiki/Thorium-based_nuclear_power https://en.wikipedia.org/wiki/Thorium-based_nuclear_power "Weinberg realized that you could use thorium in an entirely new kind of reactor, one that would have zero risk of meltdown. ... his team built a working reactor .... and he spent the rest of his 18-year tenure trying to make thorium the heart of the nation’s atomic power effort. He failed. Uranium reactors had already been established, and Hyman Rickover, de facto head of the US nuclear program, wanted the plutonium from uranium-powered nuclear plants to make bombs. Increasingly shunted aside, Weinberg was finally forced out in 1973."