Inherently safe reactors: They'd work if we'd let them: Although they shut down automatically and cannot melt or explode, advanced designs are limited to demonstrations because of economics and institutional inertia

The explosion that blew apart the Soviet Union's Chernobyl Unit 4 nuclear reactor could not happen in the light-water reactors that have almost exclusively been built elsewhere around the world. But the April 26, 1986, disaster focused worldwide attention on efforts to design reactors that are, as the industry puts it, inherently safe. The new designs rely neither on mechanical devices nor on human operators to shut them down if anything goes wrong.