B Reactor can take a tour of the reactor by advance reservation. The reactor was designed and built by E. I. du Pont de Nemours and Company based on experimental designs tested by Enrico Fermi at the University of Chicago, and tests from the X-10 Graphite Reactor at Oak Ridge National Laboratory. It was designed to operate at 250 megawatts (thermal). The reactor occupies a footprint of (about and is tall, occupying a volume of . The reactor core itself consisted of a graphite box measuring occupying a volume of and weighing . It was penetrated horizontally through its entire length by
Enrico Fermi Nuclear Generating Station was achieved on August 23, 1963. On October 5, 1966 Fermi 1 suffered a partial fuel meltdown. Two of the 92 fuel assemblies were partially damaged. According to the United States Nuclear Regulatory Commission, there was no abnormal radioactivity released to the environment. Fermi 1 was a liquid metal (sodium) cooled fast breeder reactor design. It was capable of producing 200 megawatts thermal (MWt) power or 69 MW electrical power with 26% enriched metallic uranium fuel. The enriched uranium section of the reactor (core) was a 30 inch in diameter cylinder by 30 inches high and contained 92 fuel assemblies.