The Integral Fast Reactor (IFR) was a concept that promised inexhaustible, clean, safe, proliferation-resistant energy, with waste that needed isolation for only hundreds of years rather than tens of thousands. The development of the IFR was abandoned by the US government in 1994, as it neared completion, because too many in the US Congress and Administration did not understand its potential to help control the spread of nuclear weapons. Nevertheless, the deployment of a fast-fission technology with the general characteristics of the IFR is inevitable because the growing global demand for clean energy cannot be satisfied by today's thermal reactors.