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 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. The Army plans to start demolition in 2020. Construction of the SM-1 facility Research and development of the reactor design was conducted in 1952–54 at the Oak Ridge National Laboratory, under the guidance of the Package Power Group. Funding for the reactor was approved in 1954 and bids to construct the facility were received from 18 companies, ranging in price from $2 million to $7 million. According to Time magazine of 18 July 1955, the Army selected the low bid ($2,096,753), submitted by the American Locomotive Company (ALCO Products) of Schenectady, New York, and awarded the contract in December 1954. The name "SM-1" stands for Stationary, Medium-size reactor, prototype #1. The pressurized-water reactor (PWR) design developed by the AEC was a heterogeneous, water-cooled and water-moderated, stainless steel system, using highly enriched (93%) uranium dioxide mixture as fuel. The term "package" in the name Army Package Power Reactor refers to the program objective of designing a compact nuclear power plant whose components could be packed for delivery to remote facilities aboard large military transport aircraft. The SM-1 served as the prototype for the SM-1A power plant, which was constructed at Fort Greely, Alaska between 1960–62. The reactor core itself was compact, about the size of a household dishwasher.