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 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. USACE has started dismantling the SM-1 facility, and estimate completion by 2026.
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 and 1962. The reactor core itself was compact, about the size of a household dishwasher.
At a press conference held on 19 August 1954, (then) Major General Sturgis, Chief of Engineers, announced the plan by the Army and the AEC to build the "package" power plant at Fort Belvoir. A location in a "closed area" of the garrison had been selected, near a point at which Accotink Bay (aka, Gunston Cove) joins the Potomac River. The general said the design of the package reactor resembles the nuclear power plant on the US Navy's (newly launched) nuclear submarine Nautilus. He also said the reactor could be housed in a building wide, high and long. The Army was sending out a request for proposals, that day, to "33 qualified bidders", and companies were being asked to come up with a "competitive lump-sum bid", rather than a cost-plus estimate. On 14 December 1954, the AEC announced that the contract was being given to American Locomotive Company of New York, whose $2 million bid was the lowest of the 18 proposals received. Asking companies to submit a lump-sum bid was hailed, at that time, as a sign of how much progress had been made in reactor power plant design by mid-1954, such that companies now had sufficient experience and could calculate costs with confidence.
Construction of the building to house the reactor began on 5 October 1955 in the southeast "corner" of Fort Belvoir, Virginia, alongside Gunston Cove, off the Potomac River. According to a news note in the December 1955 Bulletin of the Atomic Scientists, "Construction of the 'package' or portable reactor has been started at Fort Belvoir, VA. Alco Products is the contractor for the Defense Department and the AEC. The reactor will generate about 2,000 kilowatts of electricity, enough for a community of about 5,000 people." Alco Products supplied the reactor, pressurizer and steam generator, while Westinghouse Electric Corporation supplied the canned-rotor pumps, General Electric supplied the turbine and generator, the Lummus Company supplied the condenser, and Minneapolis-Honeywell installed the controls. By late October 1955, the Army pushed ALCO to accelerate construction towards a completion date of 10 July 1957. As a result, all major work was completed by March 1957.