SM-1 (Stationary, Medium-size reactor, prototype #1) was a 2-megawatt nuclear reactor developed by the American Locomotive Company (ALCO) and the United States Atomic Energy Commission (AEC) as part of the US Army Nuclear Power Program (ANPP) in the mid-1950s. The compact "package" reactor was designed to produce electricity and generate heat for remote military facilities. The first, the SM-1, served as the Army's primary training facility to train reactor operations personnel from all three services (Army, Navy and Air Force). In 1954, the Department of Defense placed the US Army in charge of all military nuclear power plants except those used for propulsion by the US Navy. The Army's Chief of Engineers established the US Army Engineer Reactors Group in April 1954, and decided to construct the SM-1 facility at the Corps of Engineers headquarters at Fort Belvoir, Virginia, about 18 miles (29 km) south of Washington, D.C. About 800 personnel were trained on the SM-1 during its operational life, from 1957 to 1973. The power plant was shut down in March 1973, and is monitored within a "restricted access" section of the post. Inspectors enter the shut-down operations control room every decade or so.[1] USACE has started dismantling the SM-1 facility, and estimate completion by 2026.[2][3]