Aircraft Nuclear Propulsion 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 , 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 cancelled in 1961 before that aircraft was built . Direct Air Cycle . Direct cycle nuclear engines would resemble a conventional jet engine , except that there would be no combustion chambers . The air gained from the compressor section would be 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 into a turbine , which sends it out the exhaust . The end result is that instead of using jet fuel , an aircraft could rely on 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 itself to heat it before being exhausted through the turbine . The US " Aircraft Reactor Experiment " ( ARE ) was a 2 . 5 MW thermal nuclear reactor experiment designed to attain a high power density for use as an engine in a nuclear - powered bomber . It used the molten fluoride salt NaF - ZrF - UF ( 53 - 41 - 6 mol % ) as fuel , was moderated by beryllium oxide ( BeO ) , used liquid sodium as a secondary coolant and had a peak temperature of 860 °C . It operated for a 1000 - hour cycle in 1954 . It was the first molten salt reactor . Work on this project in the US stopped after ICBM s made it obsolete . The designs for its engines can currently be viewed at the EBR - I memorial building at the Idaho National Laboratory . In 1955 , this program produced the successful X - 39 engine , two modified General Electric J47 s with heat supplied by the Heat Transfer Reactor Experiment - 1 ( HTRE - 1 ) . The first full power test of the HTRE - 1 system on nuclear power only took place in January 1956 . A total of 5004 megawatt - hours of operation was completed during the test program . The HTRE - 1 was replaced by the HTRE - 2 and eventually the HTRE - 3 unit powering the two J47s . The HTRE - 3 used " a flight - type shield system " and would probably have gone on to power the X - 6 had that program been pursued . Indirect Air Cycle . Indirect cycling involves thermal exchange outside of the core . The compressor air would be 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 and sent to the turbine . The turbine would send the air out the exhaust , providing thrust . The Indirect Air Cycle program was assigned to Pratt & Whitney , at 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 exchanger s , liquid - metal turbopump s and radiators . The Indirect Cycle program never came anywhere near producing flight - ready hardware . MX - 1589 project . On September 5 , 1951 , the USAF awarded Consolidated - Vultee a contract to fly a nuclear reactor on board a modified Convair B - 36 under the MX - 1589 project of the ANP program . The NB - 36 H Nuclear Test Aircraft ( NTA ) was to study shielding requirements for an airborne reactor , to determine whether a nuclear aircraft was feasible . This 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 plane , rather the primary purpose of the flight program was shield testing . Based on the results of the NTA , the X - 6 and the entire nuclear aircraft program was abandoned in 1961 . Abandonment . After numerous problems the project was shut down in March 1953 only to be re - opened a year later . Technological competition with the Soviet Union ( as represented by the launch of Sputnik ) , and continued strong support from the Air Force allowed the program to continue , despite divided leadership between the DOD and the AEC . The election of John F . Kennedy as President changed the course . Kennedy wrote " 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 " in his statement officially ending the ANP on March 26 , 1961 .