Experimental Breeder Reactor I
Experimental Breeder Reactor I (EBR-I) is a decommissioned research reactor and U.S. National Historic Landmark located in the desert about southeast of Arco, Idaho. It was the world's first breeder reactor. At 1:50 p.m. on December 20, 1951, it became one of the world's first electricity-generating nuclear power plants when it produced sufficient electricity to illuminate four 200-watt light bulbs. EBR-I subsequently generated sufficient electricity to power its building, and continued to be used for experimental purposes until it was decommissioned in 1964. The museum is open for visitors from  late May until early September. History. As part of the National Reactor Testing Station (since 2005 Idaho National Laboratory), EBR-I's construction started in late 1949. The reactor was designed and constructed by a team led by Walter Zinn at the Argonne National Laboratory Idaho site, known as Argonne-West. In its early stages, the reactor plant was referred to as Chicago Pile 4 (CP-4) and Zinn's Infernal Pile. Installation of the reactor at EBR-I took place in early 1951 (the first reactor in Idaho) and it began power operation on August 24, 1951. On December 20  of that year, atomic energy was successfully harvested at EBR-1 for the first time. The following day, the reactor produced enough power to light the whole building. The power plant produced 200 kW of electricity out of 1.4 MW of heat generated by the reactor. The design purpose of EBR-I was not to produce electricity but instead to validate nuclear physics theory that suggested that a breeder reactor should be possible. In 1953, experiments revealed the reactor was producing additional fuel during fission, thus confirming the hypothesis. On November 29, 1955, the reactor at EBR-I suffered a partial  meltdown during a coolant flow test. The flow test was trying to determine the cause of unexpected reactor responses to changes in coolant flow. It was subsequently repaired for further experiments, which determined that thermal expansion of the fuel rods and the thick plates supporting the fuel rods was the cause of the unexpected reactor response. Although EBR-I produced the first electricity available in-house, a nearby experimental boiling water reactor plant called BORAX-III (also designed, built, and operated by Argonne National Laboratory) was connected to external loads, powering the nearby city of Arco, Idaho in 1955, the  first time a city had been powered solely by nuclear power. Besides generating the world's first electricity from atomic energy, EBR-I was also the world's first breeder reactor and the first to use plutonium fuel to generate electricity (see also the Clementine nuclear reactor). EBR-I's initial purpose was to prove Enrico Fermi's fuel breeding principle, a principle that showed a nuclear reactor producing more fuel atoms than consumed. Along with generating electricity, EBR-1 would also prove this principle. Design. EBR-I used uranium metal fuel and NaK primary coolant. It was in this identical  to the initial configuration of the later Dounreay Fast Reactor which first went critical in 1959. Decommission and legacy. EBR-I was deactivated by Argonne in 1964 and replaced with a new reactor, Experimental Breeder Reactor II. It was declared a National Historic Landmark in 1965 with its dedication ceremony held on August 25, 1966, led by President Lyndon Johnson and Glenn T. Seaborg. It was also declared an IEEE Milestone in 2004.