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44-548: The Aircraft Nuclear Propulsion (ANP) program, and the preceding Nuclear Energy for the Propulsion of Aircraft (NEPA) project, worked to develop a nuclear propulsion system for aircraft . The United States Army Air Forces initiated Project NEPA on May 28, 1946. After funding of $ 10 million in 1947, NEPA operated until May 1951, when the project was transferred to the joint Atomic Energy Commission (AEC)/USAF ANP. The USAF pursued two different systems for nuclear-powered jet engines,

88-414: A MSR concept, the program was canceled by President Kennedy on March 26, 1961 citing the high cost with no flight-worthy reactor having been produced up to that point – "15 years and about $ 1 billion have been devoted to the attempted development of a nuclear-powered aircraft; but the possibility of achieving a militarily useful aircraft in the foreseeable future is still very remote". Also contributing to

132-617: A civilian power station concept. The result of the proposal was direction from the Atomic Energy Commission for ORNL to design, construct, and operate the Molten-Salt Reactor Experiment (MSRE). Nuclear-powered aircraft A nuclear-powered aircraft is a concept for an aircraft intended to be powered by nuclear energy. The intention was to produce a jet engine that would heat compressed air with heat from fission, instead of heat from burning fuel. During

176-525: A facility near Middletown, Connecticut . This concept would have produced far less radioactive pollution. One or two loops of liquid metal would carry the heat from the reactor to the engine. This program involved a great deal of research and development of many light-weight systems suitable for use in aircraft, such as heat exchangers, liquid-metal turbopumps and radiators . The Indirect Cycle program never came anywhere near producing flight-ready hardware. The United States Aircraft Reactor Experiment (ARE)

220-564: A nuclear aircraft program: "[a] nuclear-powered bomber is being flight tested in the Soviet Union. Completed about six months ago, this aircraft has been flying in the Moscow area for at least two months. It has been observed both in flight and on the ground by a wide variety of foreign observers from Communist and non-Communist countries." Unlike the US designs of the same era, which were purely experimental,

264-609: The Cold War , the United States and Soviet Union researched nuclear-powered bomber aircraft, the greater endurance of which could enhance nuclear deterrence , but neither country created any such operational aircraft. One inadequately solved design problem was the need for heavy shielding to protect the crew and those on the ground from radiation; other potential problems included dealing with crashes. Some missile designs included nuclear-powered hypersonic cruise missiles. However,

308-601: The Idaho National Laboratory . The U.S. designed these engines for use in a new, specially-designed nuclear bomber, the WS-125 . Although President Eisenhower eventually terminated it by cutting NEPA and telling Congress that the program was not urgent, he backed a small program for developing high-temperature materials and high-performance reactors; that program was terminated early in the Kennedy administration. In 1957,

352-652: The MX-1589 project. One of the B-36s, the NB-36H , was to be used for studying shielding requirements for an airborne reactor, while the other was to be the X-6 ; however, the program was canceled before the X-6 was completed. The first operation of a nuclear aircraft engine occurred on January 31, 1956 using a modified General Electric J47 turbojet engine. The Aircraft Nuclear Propulsion program

396-534: The Tupolev Tu-95 bomber, but with a reactor fitted in the bomb bay. The aircraft is reported to have been flown up to 40 times from 1961 to 1969. The main purpose of the flight phase was examining the effectiveness of the radiation shielding. A follow-up design, the Tu-119, was planned to have two conventional turboprop engines and two direct-cycle nuclear jet engines, but was never completed. Several other projects, like

440-558: The Air Force and the U.S. Atomic Energy Commission contracted with the Lawrence Radiation Laboratory to study the feasibility of applying heat from nuclear reactors to ramjet engines. This research became known as Project Pluto . This program was to provide engines for an unmanned cruise missile, called SLAM, for Supersonic Low Altitude Missile . The program succeeded in producing two test engines, which were operated on

484-572: The Direct Air Cycle concept, which was developed by General Electric , and Indirect Air Cycle, which was assigned to Pratt & Whitney . The program was intended to develop and test the Convair X-6 , a planned prototype for a fully functional nuclear-powered airplane. In 1952, Carswell Air Force Base in Texas was hit by a tornado, severely damaging a number of aircraft. One of the damaged airplanes

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528-451: The Direct Air Cycle concept, which was developed by General Electric , and Indirect Air Cycle, which was assigned to Pratt & Whitney . The program was intended to develop and test the Convair X-6 , but was canceled in 1961 before that aircraft was built. The total cost of the program from 1946 to 1961 was about $ 1 billion. Direct cycle nuclear engines resemble a conventional jet engine without combustion chambers . The air gained from

572-427: The US government pushed for development of a heavy bomber with jet engines. Parallel programs of nuclear and conventional aircraft development sought to achieve this goal, but progress on the nuclear plane was slow. President Dwight Eisenhower was not convinced of the need for the program, and he did not assign any urgency to it, although he did maintain funding. By the late 1950s the concept of nuclear-powered planes

616-819: The advent of ICBMs and nuclear submarines in the 1960s greatly diminished the strategic advantage of such aircraft, and respective projects were canceled. In May 1946, the United States Army Air Forces started the Nuclear Energy for the Propulsion of Aircraft (NEPA) project, which conducted studies until the Aircraft Nuclear Propulsion (ANP) program replaced NEPA in 1951. The ANP program included provisions for studying two different types of nuclear-powered jet engines: General Electric 's Direct Air Cycle and Pratt & Whitney 's Indirect Air Cycle. ANP planned for Convair to modify two B-36s under

660-405: The article noted that "The Soviet aircraft is a prototype of a design to perform a military mission as a continuous airborne alert warning system and missile launching platform." Photographs illustrated the article, along with technical diagrams on the proposed layout; these were so widely seen that one company produced a plastic model aircraft based on the diagrams in the article. An editorial on

704-531: The book The Zeppelin in the Atomic Age , which promoted the use of atomic airships. In 1959 Goodyear presented a plan for nuclear-powered airship for both military and commercial use. Several other proposals and papers were published during the next decades. The 1 December 1958 issue of Aviation Week included an article, "Soviets Flight Testing Nuclear Bomber", that claimed that the Soviets had greatly progressed

748-522: The cancellation was that the first intercontinental ballistic missiles entered into active service in September 1959 which all but eliminated the need for a nuclear-powered aircraft as a strategic deterrent. Nevertheless, the results of the ARE program prompted scientists and engineers at ORNL to submit a preliminary design proposal to the Atomic Energy Commission for a 30 MW th experimental MSR to explore MSR as

792-509: The circulating-fuel reactor program of the Pratt and Whitney Aircraft Company (PWAC). This was called the PWAR-1, the Pratt and Whitney Aircraft Reactor-1. The purpose of the experiment was to experimentally verify the theoretically predicted nuclear properties of a PWAC reactor. The experiment was only run briefly; by the end of February 1957 all data had been taken and disassembly had begun. The experiment

836-412: The compressor section is sent to a plenum that directs the air into the nuclear reactor core . An exchange takes place where the reactor is cooled, but it then heats up the same air and sends it to another plenum. The second plenum directs the air through a turbine (powering the compressor), then out the exhaust, providing thrust. The end result is that instead of using jet fuel, an aircraft could rely on

880-604: The conventional Myasishchev M-50 Bounder , a medium-range strategic bomber that performed like the United States Air Force -operated B-58 Hustler . The design was considered a failure, never entered service, and was revealed to the public on Soviet Aviation Day in 1963 at Monino , putting the issue to rest. The Soviet program of nuclear aircraft development resulted in the experimental Tupolev Tu-95LAL ( Russian : LAL- Летающая Атомная Лаборатория , lit.   'Flying Nuclear Laboratory') which derived from

924-424: The core with compressor air being sent to a heat exchanger . The nuclear reactor core would heat up pressurized water or liquid metal and send it to the heat exchanger as well. That hot liquid would be cooled by the air; the air would be heated by the liquid, sent through a turbine (powering the compressor), then out the exhaust, providing thrust. The Indirect Air Cycle program was assigned to Pratt & Whitney, at

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968-414: The ground. On May 14, 1961, the world's first nuclear ramjet engine, "Tory-IIA," mounted on a railroad car, roared to life for just a few seconds. On July 1, 1964, seven years and six months after it was born, "Project Pluto" was canceled. There were several studies and proposals for nuclear-powered airships , starting with a 1954 study by F. W. Locke Jr. for US Navy. In 1957 Edwin J. Kirschner published

1012-454: The heat from nuclear reactions for power. The General Electric program, which was based at Evendale, Ohio , was pursued because of its advantages in simplicity, reliability, suitability and quick start ability. Conventional jet engine compressor and turbine sections were used, with the compressed air run through the reactor to be heated by it before being exhausted through the turbine. Indirect cycling involves thermal exchange outside of

1056-464: The hull of a cruise missile and guarantee a range of flight ten times greater than that of other missiles." The video showed the missile evading defense systems over the Atlantic, flying over Cape Horn and finally north towards Hawaii. To date there is no publicly available evidence to verify these statements. The Pentagon stated that it is aware of a Russian test of a nuclear-powered cruise missile but

1100-580: The launch of Sputnik 1 ), and continued strong support from the Air Force allowed the program to continue, despite divided leadership between the DOD and the AEC. Numerous test facilities were funded and constructed through the 1950s and 1960–61 in order to produce a flight-worthy nuclear power unit, including one at the Oak Ridge National Laboratory (ORNL). While the ARE successfully demonstrated operation of

1144-409: The preceding Nuclear Energy for the Propulsion of Aircraft ( NEPA ) project worked to develop a nuclear propulsion system for aircraft . The United States Army Air Forces initiated Project NEPA on May 28, 1946. NEPA operated until May 1951, when the project was transferred to the joint Atomic Energy Commission (AEC)/USAF ANP. The USAF pursued two different systems for nuclear-powered jet engines,

1188-400: The radioactive source could be kept safely underground between the test flights. A monitoring system dubbed " Project Halitosis " measured radioactive gases from the reactor. The NB-36H completed 47 test flights and 215 hours of flight time (during 89 of which the reactor was operated) between September 17, 1955, and March 1957 over New Mexico and Texas . The test flights revealed, that with

1232-536: The results of the NTA, the X-6 and the entire nuclear aircraft program was abandoned in 1961. As part of the AEC/USAF ANP program, in 1956 modified General Electric J47s were first operated on nuclear power using a reactor test assembly known as Heat Transfer Reactor Experiment 1 (HTRE-1). HTRE-1, which used vertically-oriented control rods, was reconfigured with a removable core to become HTRE-2 for additional testing. HTRE-3

1276-449: The shielding used, the crew would not be endangered by radiation from the reactor, including with low-altitude flights, but that there was a risk of radioactive contamination in the event of an accident. In 1957, at the end of its run of flight tests, the NB-36H was decommissioned and scrapped at Carswell. The nuclear reactor was removed. With Cold War tensions increasing in the late 1950s,

1320-452: The supersonic Tupolev Tu-120 , reached only the design phase. In February 2018, Russian President Vladimir Putin said that Russia had developed a new, nuclear-powered cruise missile with nuclear warhead that can evade air and missile defenses and hit any point on the globe. According to the statements, its first flight test occurred in 2017. The missile was said to feature "a small-size super-powerful power plant that can be placed inside

1364-550: The system is still under development and had crashed in the Arctic in 2017. A RAND Corporation researcher specializing in Russia said "My guess is they're not bluffing, that they've flight-tested this thing. But that's incredible." According to a CSIS fellow, such a nuclear-powered missile "has an almost unlimited range – you could have it flying around for long periods of time before you order it to hit something". Putin's statements and

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1408-526: The topic accompanied the article. Concerns were soon expressed in Washington that "the Russians were from three to five years ahead of the US in the field of atomic aircraft engines and that they would move even further ahead unless the US pressed forward with its own program". These concerns caused continued but temporary funding of the US's own program. The aircraft in the photographs was later revealed to be

1452-422: Was a B-36 bomber, and Convair suggested to the Air Force that it should be converted into an early prototype for the X-6, instead of being repaired. The Air Force agreed to this plan, and provided funding for an overhaul of the airplane. The intention was to test fly an airplane with a functioning nuclear engine on board, but with it not yet powering the airplane at this stage. The original crew and avionics cabin

1496-440: Was a 2.5 MW th thermal -spectrum nuclear reactor experiment designed to attain a high power density and high output temperature for use as an engine in a nuclear-powered bomber aircraft. The advantage of a nuclear-powered aircraft over a conventionally-powered aircraft is that it could remain airborne orders of magnitude longer and provide an effective nuclear strategic deterrent to a nuclear-armed Soviet adversary. The ARE

1540-646: Was built separately to test horizontally-oriented control rods as appropriate for use in an airframe. The decommissioned HTRE-2 and HTRE-3 reactors and test assemblies can be viewed by the public in the Experimental Breeder Reactor I parking lot at Idaho National Laboratory . On February 5, 1957, another reactor was made critical at the Critical Experiments Facility of the Oak Ridge National Laboratory (ORNL) as part of

1584-401: Was circulated around the primary coolant to transfer heat to a water radiator where heat output was dumped to atmosphere. Reactivity control rods were installed and it was found that the control rods did not determine the output power of the ARE; rather, the power demand did, which affected the outlet and inlet temperatures because of the negative temperature coefficient of reactivity . The ARE

1628-422: Was increasingly seen by Congress as redundant, given the ongoing advances in supersonic aviation and ballistic missile development. In March 1961, shortly after he took office, President John F. Kennedy canceled the program. In his statement, Kennedy commented that the prospect of nuclear-powered planes was still very remote, despite 15 years of development and expenditure of around $ 1 billion. The Convair X-6

1672-578: Was never built, and the NB-36H is to date the only American aircraft to carry an operational nuclear reactor. The scientific work carried out for the project did have some lasting value however, including methods for handling liquid metals and fused salts, which aided the development of nuclear generators and reactors used by NASA . General characteristics Performance Related development Aircraft of comparable role, configuration, and era Related lists Aircraft Nuclear Propulsion The Aircraft Nuclear Propulsion ( ANP ) program and

1716-550: Was operated at power for 221 hours up to a peak of 2.5 MW th . On September 5, 1951, the USAF awarded Convair a contract to fly a nuclear reactor on board a modified Convair B-36 Peacemaker under the MX-1589 project of the ANP program. The NB-36H Nuclear Test Aircraft (NTA) was to study shielding requirements for an airborne reactor, to determine whether a nuclear aircraft was feasible. This

1760-425: Was replaced by a massive lead- and rubber-lined 11 ton crew section for a pilot, copilot, flight engineer and two nuclear engineers. Even the small windows had 25-to-30-centimeter-thick (10–12 in) lead glass . The aircraft was fitted with a 1-megawatt air-cooled reactor , with a weight of 35,000 pounds (16,000 kg). This was hung on a hook in the middle bomb bay to allow for easy loading and unloading, so that

1804-475: Was run at essentially zero nuclear power. The operating temperature was held constant at approximately 675 °C (1,247 °F), which corresponds closely to the design operating temperature of the PWAR-l moderator; this temperature was maintained by external heaters. Like the 2.5 MWt ARE, the PWAR-1 used NaF-ZrF4-UF4 as the primary fuel and coolant. Technological competition with the Soviet Union (as represented by

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1848-466: Was terminated by President Kennedy after his annual budget message to Congress in 1961. The Oak Ridge National Laboratory researched and developed nuclear aircraft engines. Two shielded reactors powered two General Electric J87 turbojet engines to nearly full thrust. Two experimental reactors, HTRE-2 with its turbojet engines intact, and HTRE-3 with its engines removed, are at the EBR-1 facility south of

1892-412: Was the first molten salt reactor (MSR) to be built and operated. It used the molten fluoride salt NaF - ZrF 4 - UF 4 (53-41-6 mol%) as fuel , was moderated by a hexagonal-configuration beryllium oxide (BeO), and had a peak temperature of 860 °C. A redundant liquid sodium coolant system was used to cool the moderator and reflector materials. A secondary helium gas coolant loop

1936-477: Was the only known airborne reactor experiment by the U.S. with an operational nuclear reactor on board. The NTA flew a total of 47 times testing the reactor over West Texas and Southern New Mexico. The reactor, named the Aircraft Shield Test Reactor (ASTR), was operational but did not power the aircraft; the primary purpose of the flight program was testing the effectiveness of the shielding. Based on

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