Construction of the Mound facility began in 1946 to support the early atomic weapons programs. Early work at the site involved production of polonium-beryllium initiators used in early atomic weapons and research related to radionuclides and detonators. In the 1950s, the facility manufactured a variety of nuclear weapons parts, including cable assemblies, explosive detonators, and electronic firing sets that activated them. The Mound Site evolved into an integrated research, development, and production facility performing work in support of the U.S. Department of Energy's (DOE's) weapons and energy programs, which included stable isotope separation, fossil fuels research, tritium recovery for reuse in weapons, development of radioisotopic thermoelectric generators that provided electrical power for space exploration (Galileo), and other nonnuclear research and development. The plant, which was in operation from 1948 to 2003, was situated on 182 acres. In 1983, DOE purchased an additional 124 acres of land south of the original property, but that property remained undeveloped. At its peak the Mound facility encompassed 116 buildings.