Oak Ridge National Laboratory was completed, later renamed to "Oak Ridge National Laboratory". The site was chosen for the X-10 Graphite Reactor, used to show that plutonium can be created from enriched uranium. Enrico Fermi and his colleagues developed the world's second self-sustaining nuclear reactor after Fermi's previous experiment, the Chicago Pile-1. The X-10 was the first reactor designed for continuous operation. After the end of World War II the demand for weapons-grade plutonium fell and the reactor and the laboratory's 1000 employees were no longer involved in nuclear weapons. Instead, it was used for scientific research. In 1946 the first medical isotopes were
Enrico Fermi Nuclear Generating Station that allowed the flow of liquid sodium into the reactor. The blockage caused an insufficient amount of coolant to enter the fuel assembly; this was not noticed by the operators until the core temperature alarms sounded. Several fuel rod subassemblies reached high temperatures of around (with an expected range near 580 °F, 304 °C), causing them to melt. Following an extended shutdown that involved fuel replacement, repairs to vessel, and cleanup, Fermi 1 restarted in July 1970 and reached full power. Due of lack of funds and aging equipment it was finally shut down permanently on November 27, 1972, and