The fact that we can is probably the reason for the fears around the reactor. People don't fear the technical limitations of a well-build and well-managed safe reactor, and those can be built. But they fear the danger of the corruption and corner-cutting in some countries which is very difficult to constrain, which will lead to building an unsafe reactor.

At the height of the Chernobyl disaster, calculations were suggesting a vast swath of Europe could be rendered uninhabitable by humans for several generations in the melt-to-groundwater-detonation scenario. As it stands, an area of diameter slightly smaller than the length of Manhattan is still considered high-risk for permanent habitation.