The Army Nuclear Power Program (ANPP) was a program of the United States Army to develop small nuclear reactors to generate electrical and space-heating energy primarily at remote, relatively inaccessible sites. The ANPP tried both pressurized water reactors and boiling water reactors, and had several accomplishments, but ultimately it was considered to be "a solution in search of a problem." The U.S. Army Engineer Reactors Group managed this program and it was headquartered at Fort Belvoir, Virginia. The program began in 1954 as the Army Reactors Branch and had effectively terminated by about 1977, with the last class of NPP operators graduating in 1977. Work continued for some time thereafter either for decommissioning of the plants or placing them into SAFSTOR (long term storage and monitoring before decommissioning). The current development of small modular reactors has led to a renewed interest in military applications, e.g. in Project Pele.COL Paul E. Roege - Can nuclear energy fill critical gaps in the military energy portfolio? @ TEAC3 - YouTube
Background There was interest in the possible application of nuclear power to land-based military needs as early as 1952. A memo from the Secretary of Defense, dated 10 February 1954, assigned the Army the responsibility for "developing nuclear power plants to supply heat and electricity at remote and relatively inaccessible military installations." The Secretary of the Army established the Army Nuclear Power Program and assigned it to the Corps of Engineers.Army Nuclear Power Program: Past, Present, Future. A briefing document prepared and presented to the Ad Hoc Study Group of the Army Scientific Advisory Panel, 10–11 February 1969
The Atomic Energy Act of 1954 made the Atomic Energy Commission (AEC) responsible for R&D in the nuclear field, so that the ANPP then became a joint interagency 'activity' of the Department of the Army (DA) and the AEC. When the Atomic Energy Act was revised in 1954, Paragraph 91b authorized the Department of Defense to obtain special nuclear material for use in defense utilization facilities. The focus of the Army Nuclear Power Program was on power production facilities, while the Naval Reactors Program concentrated on nuclear propulsion for submarines and ships. On 9 April 1954, the Chief of Engineers established the US Army Engineer Reactors Group to perform the missions assigned by DA. Essentially, these missions were to: conduct R&D, with the AEC, on nuclear power plant development; operate the Corps of Engineers nuclear power plants; carry out training in support of the plants; provide technical support to other agencies as required; develop programs for application of nuclear reactors to military needs.
In a Department of the Army Approved Qualitative Materiel Development Objective for Nuclear Power Plants, dated 7 January 1965, these objectives were stated for the program:
Reduction or elimination of dependence on [fossil] fuel sources. Reduction or elimination of logistic burden necessary to support conventional power plants. Reliable operation. Infrequent refueling and maintenance. Reduced crew size, with the ultimate goal of unattended operation. Transportability, mobility, and reaction times compatible with the mission or equipment to be supported. Improved cost-effectiveness.
The AEC ultimately concluded that the probability of achieving the objectives of the Army Nuclear Power Program in a timely manner and at a reasonable cost was not high enough to justify continued funding of its portion of projects to develop small, stationary, and mobile reactors. Cutbacks in military funding for long-range research and development because of the Vietnam War led the AEC to phase out its support of the program in 1966. The costs of developing and producing compact nuclear power plants were so high that they could be justified only if the reactor had a unique capability and filled a clearly defined objective backed by DOD. After that, the Army's participation in nuclear power plant research and development efforts steadily declined and eventually stopped altogether.Pfeffer, Macon, Nuclear Power: An Option for the Army's Future, Army Logistician, PB 700-01-5, Vol 33, Issue 5, Sept/Oct 2001, retrieved from on January 30, 2009
List of plants Eight plants were constructed. Due to the requirement for a small physical size, all these reactors other than the MH-1A used highly enriched uranium (HEU). The MH-1A had more space to work with, and more weight-carrying capacity, so this was a low-enrichment reactor; i.e., larger and heavier. The MH-1A was briefly considered for use in Vietnam, but the idea of anything nuclear in Vietnam was quickly rejected by the State Department.
The plants are listed in order of their initial criticality. See the gallery of photos in the next section. Sources for this data include the only known book on the ANPP, by Suid,Suid, L. H., The Army's Nuclear Power Program: The Evolution of a Support Agency, Greenwood (1990), and a DOE document.
Key to the codes: First letter: S – stationary, M – mobile, P – portable. Second letter: H – high power, M – medium power, L – low power. Digit: Sequence number. Third letter: A indicates field installation.
Of the eight built, six produced operationally useful power for an extended period. Many of the designs were based on United States Naval reactors, which were proven compact reactor designs.
SM-1
SM-1: 2 MW electric. Fort Belvoir, Virginia, Initial criticality April 8, 1957 (several months before the Shippingport Reactor) and the first U.S. nuclear power plant to be connected to an electrical grid. Used primarily for training and testing, rather than power generation for Ft. Belvoir. The plant was designed by the American Locomotive Company (renamed ALCO Products, in 1955), and was the first reactor developed under the Army Nuclear Power Program. See the SM-1 image gallery, below. This plant was a tri-service training facility, with both the US Navy and Air Force sending personnel to be trained on shore-based facilities (the Navy had a different stand-alone program for ship-based nuclear power, which is still in operation). The SM-1 and associated training facilities at Ft. Belvoir were the only training facility for shore-based military power plants. The plant cooled its condensers using the waters of the Potomac River. For about the first 10 years of its operation, the SM-1 unknowingly released tritium into the waters of the Chesapeake Bay, until the development of the Packard Tri-Carb detector, which was the first detector system capable of detecting the low-energy beta decay of tritium. The instrumentation in the SM-1 pre-dated the development of solid-state devices and used vacuum tubes.
SL-1
SL-1: Boiling water reactor, 200 kW electrical, 400 kW thermal for heating, National Reactor Testing Station, Idaho. Initial criticality August 11, 1958. The SL-1 was designed by the Argonne National Laboratory to gain experience in boiling water reactor operations, develop performance characteristics, train military crews, and test components. Combustion Engineering was awarded a contract by the AEC to operate the SL-1 and in turn employed the Army's military operating crew to continue running the plant. This BWR was specifically designed to power DEW line stations. On January 3, 1961, the reactor was being prepared for restart after a shutdown of eleven days over the holidays. Maintenance procedures were in progress which required the main central control rod to be manually withdrawn a few inches to reconnect it to its drive mechanism; at 9:01 p.m. this rod was suddenly withdrawn too far, causing SL-1 to go prompt critical instantly. In four milliseconds, the heat generated by the resulting enormous power surge caused fuel in the core to explosively vaporize. The nuclear fission reaction directly heated the water, flashing a large amount into steam. Melting aluminum reacted with water producing hydrogen gas. The exploding fuel plates, violent metal-water reaction, and expanding water vapor pressed upwards on the water above the core, sending a pressure wave that struck the top of the reactor vessel. The force impinged on the lid of the reactor vessel, causing water and steam to spray from the top of the vessel. This extreme form of water hammer propelled top head shielding, remnants of fuel plates, five loose shield plugs, a nozzle flange, and the entire reactor vessel upwards. A later investigation concluded that the vessel had jumped in the air before striking the overhead bridge crane drive shaft. The vessel settled back into its original location, leaving little evidence of this except scattered debris.IDO-19311 Final Report of SL-1 Recovery Operation, Idaho Test Station, General Electric Corporation, July 27, 1962. The spray of water and steam knocked two operators onto the floor, killing one and severely injuring another. One of the loose shield plugs on top of the reactor vessel impaled the third man through his groin and exited his shoulder, pinning him to the ceiling.The victims were Army Specialists John A. Byrnes (age 27) and Richard Leroy McKinley (age 22), and Navy Seabee Construction Electrician First Class (CE1) Richard C. Legg (age 26). It was later established that Byrnes (the reactor operator) had lifted the rod and caused the excursion, Legg (the shift supervisor) was standing on top of the reactor vessel and was impaled and pinned to the ceiling, and McKinley, the trainee who stood nearby, was later found alive by rescuers. All three men succumbed to injuries from physical trauma; the radiation from the nuclear excursion would have given the men no chance of survival. This was the only fatal incident at a US nuclear power reactor, which destroyed the reactor. This incident was important in the development of commercial power because future designs prevented the core from going critical with the removal of a single rod.
PM-2A
PM-2A: 2 MW electric, plus heating. Camp Century, Greenland. Initial criticality October 3, 1960. The first "portable" nuclear power reactor. Brought to Greenland in parts, assembled, operated, disassembled, shipped back to United States.PM-2A The PM-2A in Camp Century was designed by the American Locomotive Company to demonstrate the ability to assemble a nuclear power plant from prefabricated components in a remote, arctic location. PM-2A operated at a uranium-235 enrichment of 93 percent.
In 1961, after the SL-1 plant explosion, General Alvin Luedecke, the General Manager of the AEC, temporarily prevented the startup of the PM-2A until an interlock could be installed on the central control rod. While the interlock could be operated by personnel, General Luedecke would have to be notified first.Radiation Safety and Regulation Hearings, Joint Committee on Atomic Energy, US Congress, June 12–15, 1961, including SL-1 Accident Atomic Energy Commission Investigation Board Report, Joint Committee on Atomic Energy Congress of the United States, First Session on Radiation Safety and Regulation, Washington, DC, see page 185. The PM-2A was the only reactor besides SL-1 that had a central control rod that could startup the reactor on its own.
We gave explicit instructions on the 8th of January that this reactor, which was shut down at the time, would not be started until we had reviewed the situation.
It was necessary for us to issue instructions to modify mechanisms of the PM-2A so that no single rod could be raised to a point where criticality could automatically occur.
PM-2A successfully powered Camp Century for three years. The pressure vessel was also used to investigate neutron embrittlement in carbon steel. This plant was shut down 1963–1964. However despite the reactor's successes, Project Iceworm was never fielded and Camp Century was later abandoned.
ML-1