Few scientific phenomena have been associated with such an eerie blend of menace and promise as nuclear fission. Within seven years of the discovery of fission, in which a heavy atomic nucleus is split into smaller fragments to release energy, the world watched as the United States used it to destroy two Japanese cities. Less than ten years after those violent events, proponents of nuclear fission were instead touting it as a peaceful source of electricity that would be so plentiful and inexpensive to produce that people wouldn’t have to pay for what they use. But that has not been the case.