191-402: The Nuclear Engine for Rocket Vehicle Application ( NERVA ; / ˈ n ɜːr v ə / ) was a nuclear thermal rocket engine development program that ran for roughly two decades. Its principal objective was to "establish a technology base for nuclear rocket engine systems to be utilized in the design and development of propulsion systems for space mission application". It was a joint effort of
382-451: A thrust-to-weight ratio of 1:1, which is needed to overcome the gravity of the Earth at launch. Over the next twenty-five years, U.S. nuclear thermal rocket designs eventually reached thrust-to-weight ratios of approximately 7:1. This is still a much lower thrust-to-weight ratio than what is achievable with chemical rockets, which have thrust-to-weight ratios on the order of 70:1. Combined with
573-410: A working mass in a direction opposite to their desired trajectory. In conventional designs, this is accomplished by heating a fluid and allowing it to escape through a rocket nozzle . The energy needed to produce the heat is provided by a chemical reaction in the fuel, which may be mixed together as in the case of most solid fuel rockets , or separate tanks as in most liquid fuel rockets . Selecting
764-497: A Kiwi B4 engine and PARKA, a Kiwi reactor used for testing at LASL. The two reactors were run 4.9 meters (16 ft), 2.7 meters (9 ft) and 1.8 meters (6 ft) apart, and reactivity measurements were taken. These tests showed that neutrons produced by one reactor did indeed cause fissions in another, but that the effect was negligible: 3, 12 and 24 cents respectively. The tests demonstrated that nuclear rocket engines can be clustered, just as chemical ones often are. SNPO chose
955-634: A RIFT with NERVA as the upper stage of a Saturn C-3 , but the C-3 was replaced soon after by the more powerful C-4 and ultimately the C-5, which became the Saturn V . Only in July 1962, after much debate, did NASA finally settle on lunar orbit rendezvous , which could be performed by Saturn V, negating the need for the larger and more expensive Nova, which was abandoned. The RIFT test vehicle would be 111 meters (364 ft) tall, about
1146-466: A byproduct of its own reaction. The High Flux Isotope Reactor built in 1965 had the highest neutron flux of any reactor at the time. It improved upon the work of the X-10 reactor, producing more medical isotopes as well as allowing higher fidelity of materials research. Researchers in the biology division studied the effects of chemicals on mice, including petrol fumes , pesticides , and tobacco . In
1337-485: A consortium of companies to conduct a study on electric thrusters powered by nuclear energy, known as Nuclear Electric Propulsion. The study outlines the roadmap for the launch of a nuclear propulsion demonstrator in 2035. Current solid-core nuclear thermal rocket designs are intended to greatly limit the dispersion and break-up of radioactive fuel elements in the event of a catastrophic failure. As of 2013, an NTR for interplanetary travel from Earth orbit to Mars orbit
1528-665: A conventional and quantum scale . ORNL is home to a field site for the National Ecological Observatory Network (NEON), which has a field office nearby. The Department of Energy works closely with the Tennessee Wildlife Resources Agency out of ORNL to monitor forest ecology for the surrounding Appalachians & Cumberland Plateau Domain of NEON. There are two neutron sources at ORNL; the High Flux Isotope Reactor (HFIR) and
1719-404: A diverse range of fuels, and to improve the efficiency of energy delivery both to power plants and end users. The Center for Molecular Biophysics conducts research into the behaviour of biological molecules in various conditions. The center hosts projects that examine cell walls for biofuel production, use neutron scattering to analyse protein folding , and simulate the effect of catalysis on
1910-452: A factor of 2 to 100 compared to conventional nuclear fuels . Fission-fragment rocket using Am was proposed by George Chapline at Lawrence Livermore National Laboratory (LLNL) in 1988, who suggested propulsion based on the direct heating of a propellant gas by fission fragments generated by a fissile material. Ronen et al. demonstrate that Am can maintain sustained nuclear fission as an extremely thin metallic film, less than 1/1000 of
2101-436: A factor of two. The next objective was to run the reactors continuously for an extended length of time. The NRX A5 was started up on 8 June 1966, and run at full power for fifteen and a half minutes. During cooldown, a bird landed on the nozzle and was asphyxiated by the nitrogen or helium gas, dropping onto the core. It was feared that it might block the propellant lines or create uneven heating before being blown out again when
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#17328554601402292-505: A federal agency that conducted aeronautical research; and Allen F. Donovan from Ramo-Wooldridge , an aerospace corporation. After hearing input on several designs, the Mills committee recommended in March 1955 that development proceed, with the aim of producing a nuclear rocket upper stage for an intercontinental ballistic missile (ICBM). York created a new division at Livermore, and Bradbury created
2483-460: A full-page ad in the Wall Street Journal with a picture of the test and the caption: "On to Mars!" The reactor was restarted on 15 October. Originally this was intended to test the nozzle, but that was dropped as it was close to its design maximum of 2,270 K (2,000 °C). Instead, the turbopump was tested. The engine was powered up to 40 MW, the control drums were locked in place, and
2674-542: A given design, the temperature that can be attained is typically determined by the materials chosen for reactor structures, the nuclear fuel, and the fuel cladding. Erosion is also a concern, especially the loss of fuel and associated releases of radioactivity. Solid core nuclear reactors have been fueled by compounds of uranium that exist in solid phase under the conditions encountered and undergo nuclear fission to release energy. Flight reactors must be lightweight and capable of tolerating extremely high temperatures, as
2865-414: A heat source releases thermal energy into a gaseous propellant inside the body of the engine, and a nozzle at one end acts as a very simple heat engine: it allows the propellant to expand away from the vehicle, carrying momentum with it and converting thermal energy to coherent kinetic energy. The specific impulse (Isp) of the engine is set by the speed of the exhaust stream. That, in turn, varies as
3056-415: A large volume of chemicals can be replaced by a small reactor. As the heat source is independent of the working mass, the working fluid can be selected for maximum performance for a given task, not its underlying reaction energy. Due to its low molecular mass, hydrogen is normally used. This combination of features allows a nuclear engine to outperform a chemical one; they generally aim to have at least twice
3247-537: A larger design in the Space Thermal Nuclear Propulsion (STNP) program. Advances in high-temperature metals, computer modeling, and nuclear engineering, in general, resulted in dramatically improved performance. While the NERVA engine was projected to weigh about 6,803 kilograms (14,998 lb), the final STNP offered just over 1/3 the thrust from an engine of only 1,650 kilograms (3,640 lb) by improving
3438-744: A lithium-sulfide battery with a theoretical energy density three to five times greater than existing lithium ion batteries . ORNL provides resources to the United States Department of Homeland Security and other defense programs. The Global Security and Nonproliferation (GS&N) program develops and implements policies, both US based and international, to prevent the proliferation of nuclear material . The program has developed safeguards for nuclear arsenals, guidelines for dismantling arsenals, plans of action should nuclear material fall into unauthorised hands, detection methods for stolen or missing nuclear material, and trade of nuclear material between
3629-465: A lunar shuttle. The conclusion of this nine-volume report, which was delivered in March 1965, and of a follow-up study, was that these missions could be carried out with a 4,100 MW engine with a specific impulse of 825 seconds (8.09 km/s). This was considerably smaller than had originally been thought necessary. From this emerged a specification for a 5,000 MW nuclear rocket engine, which became known as NERVA II. The first phase of Project Rover, Kiwi,
3820-459: A major breakthrough in its capacity to automate Pu-238 production which helped push annual production from 50 grams to 400 grams, moving closer to NASA 's goal of 1.5 kilograms per year by 2025 in order to sustain its space exploration programs. ORNL conducts research and development activities that span a wide range of scientific disciplines. Many research areas have a significant overlap with each other; researchers often work in two or more of
4011-453: A marginally reduced fuel cost. Yet another mark in favor of hydrogen is that at low pressures it begins to dissociate at about 1500 K, and at high pressures around 3000 K. This lowers the mass of the exhaust species, increasing I sp . Early publications were doubtful of space applications for nuclear engines. In 1947, a complete nuclear reactor was so heavy that solid core nuclear thermal engines would be entirely unable to achieve
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#17328554601404202-449: A meeting. He declared that there would be no "quick fix". He criticized LASL's management structure and called for LASL to adopt a project management structure. He wanted the case of the vibration problems thoroughly investigated, and the cause definitely known before corrective action was taken. Three SNPO staff (known at LASL as the "three blind mice") were assigned to LASL to ensure that his instructions were carried out. Finger assembled
4393-524: A millimeter thick. Am requires only 1% of the mass of U or Pu to reach its critical state. Ronen's group at the Ben-Gurion University of the Negev further showed that nuclear fuel based on Am could speed space vehicles from Earth to Mars in as little as two weeks. The Am as a nuclear fuel is derived from the fact that it has the highest thermal fission cross section (thousands of barns ), about 10x
4584-575: A minute or two at each level to check the instruments, before finally increasing to full power at 1,096 MW. The reactor ran flawlessly, and only had to be shut down after 40 seconds because the hydrogen was running out. The test demonstrated that NERVA had the designed specific impulse of 811 seconds (7.95 km/s); solid-propellant rockets have a maximum impulse of around 300 seconds (2.9 km/s) and chemical rockets with liquid propellant seldom achieve more than 450 seconds (4.4 km/s). Executives at Aerojet and Westinghouse were so pleased they took out
4775-660: A neutron moderator. There was also concern about what would happen when it sank 3.2 kilometers (2 mi) down to the bottom of the Atlantic, where it would be under a crushing pressure. The possible impact on marine life, and indeed what marine life was down there, all had to be considered. The main bottleneck in the NERVA program was the test facilities at Jackass Flats. Test Cell C was supposed to be complete in 1960. NASA and AEC did not request funds for further construction, but Anderson provided them anyway. There were construction delays, forcing Anderson to intervene personally. He assumed
4966-556: A new one called N Division at LASL under the leadership of Raemer Schreiber , to pursue it. In March 1956, the Armed Forces Special Weapons Project (AFSWP), the agency responsible for the management of the national nuclear weapons stockpile, recommended allocating $ 100 million to the nuclear rocket engine project over three years for the two laboratories to conduct feasibility studies and the construction of test facilities. Eger V. Murphree and Herbert Loper at
5157-527: A novel type of nuclear rocket . Since the thermal absorption cross section of Am is very high, the best way to obtain Am is by the capture of fast or epithermal neutrons in Americium-241 irradiated in a fast reactor . However, fast spectrum reactors are not readily available. Detailed analysis of Am breeding in existing pressurized water reactors (PWRs) was provided. Proliferation resistance of Am
5348-554: A nuclear space engine, as well as previous tests of fuel rods and ion engines . Development of solid core NTRs started in 1955 under the Atomic Energy Commission (AEC) as Project Rover and ran to 1973. Work on a suitable reactor was conducted at Los Alamos National Laboratory and Area 25 (Nevada National Security Site) in the Nevada Test Site . Four basic designs came from this project: KIWI, Phoebus, Pewee, and
5539-514: A nuclear-powered upper stage for the United States Air Force intercontinental ballistic missiles . Nuclear thermal rocket engines promised to be more efficient than chemical ones. After the formation of NASA in 1958, Project Rover was continued as a civilian project and was reoriented to producing a nuclear powered upper stage for NASA's Saturn V Moon rocket. Reactors were tested at very low power before being shipped to Jackass Flats in
5730-594: A political patron in Senator Clinton P. Anderson from New Mexico (where LASL was located). The deputy chairman of the United States Congress Joint Committee on Atomic Energy (JCAE), Anderson was close to von Neumann, Bradbury and Ulam. He managed to secure funding in January 1957. All work on the nuclear rocket was consolidated at LASL, where it was given the codename Project Rover ; Livermore
5921-472: A postponement due to inclement weather. NRX A6 was started up again on 15 December. It ran at full power (1,125 MW) with a chamber temperature of over 2,270 K (2,000 °C) and pressure of 4,089 kilopascals (593.1 psi ), and a flow rate of 32.7 kilograms per second (4,330 lb/min). It took 75.3 hours to cool the reactor with liquid nitrogen. On examination, it was found that the beryllium reflector had cracked due to thermal stress. The test caused
NERVA - Misplaced Pages Continue
6112-602: A president had visited a nuclear weapons laboratory. He brought with him a large entourage that included Lyndon Johnson , McGeorge Bundy , Jerome Wiesner , Harold Brown , Donald Hornig , Glenn Seaborg , Robert Seamans, Harold Finger, Clinton Anderson, Howard Cannon and Alan Bible . The next day, they flew to Jackass Flats, making Kennedy the only president to ever visit a nuclear test site. Project Rover had received $ 187 million in 1962, and AEC and NASA were asking for another $ 360 million in 1963. Kennedy drew attention to his administration's budgetary difficulties, and asked what
6303-462: A prize cow can have multiple eggs extracted and thus, through in vitro fertilisation , have many more offspring than would naturally be possible. In 1974 Alvin Weinberg, director of the lab for 19 years, was replaced by Herman Postma , a fusion scientist. In 1977 construction began for 6 metre (20 foot) superconducting electromagnets , intended to control fusion reactions . The project
6494-599: A propellant gas. Project 242 studied the application of this propulsion system to a crewed mission to Mars. Preliminary results were very satisfactory, and it has been observed that a propulsion system with these characteristics could make the mission feasible. Another study focused on the production of Am in conventional thermal nuclear reactors. In 2022, the European Space Agency launched an initiative called "Preliminary European Reckon on Nuclear Electric Propulsion for Space Applications" (RocketRoll) and commissioned
6685-434: A series of groundbreaking scientific papers that considered how nuclear technology might be applied to interplanetary travel . The papers examined both nuclear-thermal and nuclear-electric propulsion. Through Project Rover , Los Alamos National Laboratory began developing nuclear thermal engines as soon as 1955 and tested the world's first experimental nuclear rocket engine, KIWI-A , in 1959. This work at Los Alamos
6876-439: A set temperature is reached, the reactor is quickly turned off again. During these pulses, the power being produced is far greater than the same sized reactor could produce continually. The key to this approach is that while the total amount of fuel that can be pumped through the reactor during these brief pulses is small, the resulting efficiency of these pulses is much higher. Generally, the designs would not be operated solely in
7067-533: A team of vibration specialists from other NASA centers, and along with staff from LASL, Aerojet and Westinghouse, conducted a series of "cold flow" reactor tests using fuel elements without fissionable material. RIFT was cancelled in December 1963. Although its reinstatement was frequently discussed, it never occurred. A series of design changes were made to address the vibration problem. In the Kiwi B4D test on 13 May 1964,
7258-609: A theoretical maximum specific impulse that is 3 to 4.5 times greater than those of chemical rockets. In 1944, Stanisław Ulam and Frederic de Hoffmann contemplated the idea of controlling the power of nuclear explosions to launch space vehicles. After World War II, the U.S. military started the development of intercontinental ballistic missiles (ICBM) based on the German V-2 rocket designs. Some large rockets were designed to carry nuclear warheads with nuclear-powered propulsion engines. As early as 1946, secret reports were prepared for
7449-508: Is being studied at Marshall Space Flight Center with Glenn Research Center . In historical ground testing, NTRs proved to be at least twice as efficient as the most advanced chemical engines, which would allow for quicker transfer time and increased cargo capacity. The shorter flight duration, estimated at 3–4 months with NTR engines, compared to 6–9 months using chemical engines, would reduce crew exposure to potentially harmful and difficult to shield cosmic rays . NTR engines, such as
7640-510: Is easier to cast at a similar cost. In 2003 the partners received an R&D 100 award from R&D magazine and in 2009 received an award for "excellence in technology transfer" from the Federal Laboratory Consortium for the commercialisation of the steel. There is a high-temperature materials lab at ORNL that permits researchers from universities, private companies and other government initiatives to use their facilities. As
7831-519: Is heated to a high temperature in a nuclear reactor and then expands through a rocket nozzle to create thrust . The external nuclear heat source theoretically allows a higher effective exhaust velocity and is expected to double or triple payload capacity compared to chemical propellants that store energy internally. NTRs have been proposed as a spacecraft propulsion technology, with the earliest ground tests occurring in 1955. The United States maintained an NTR development program through 1973 when it
NERVA - Misplaced Pages Continue
8022-525: Is managed by UT–Battelle , a limited liability partnership between the University of Tennessee and the Battelle Memorial Institute , formed in 2000 for that purpose. The annual budget is US$ 2.4 billion. As of 2021 there is a staff of 5,700 working at ORNL, around 2,000 of whom are scientists and engineers, and an additional 3,200 guest researchers annually. There are five campuses on
8213-503: Is proposed to operate at temperatures above the melting point of solid nuclear fuel and cladding, with the maximum operating temperature of the engine instead of being determined by the reactor pressure vessel and neutron reflector material. The higher operating temperatures would be expected to deliver specific impulse performance on the order of 1300 to 1500 seconds (12.8-14.8 kN·s/kg). A liquid-core reactor would be extremely difficult to build with current technology. One major issue
8404-415: Is that the reaction time of the nuclear fuel is much longer than the heating time of the working fluid. If the nuclear fuel and working fluid are not physically separated, this means that the fuel must be trapped inside the engine while the working fluid is allowed to easily exit through the nozzle. One possible solution is to rotate the fuel/fluid mixture at very high speeds to force the higher-density fuel to
8595-589: Is the case for all designated user facilities, the resources of the High Temperature Materials Laboratory are available for free if the results are published; private research is permitted but requires payment. The Center for Nanophase Materials Sciences (CNMS) researches the behaviour and fabrication of nanomaterials . The center emphasises discovery of new materials and the understanding of underlying physical and chemical interactions that enable creation of nanomaterials. In 2012, CNMS produced
8786-521: Is the largest science and energy national laboratory in the Department of Energy system by size and third largest by annual budget. It is located in the Roane County section of Oak Ridge. Its scientific programs focus on materials , nuclear science , neutron science, energy, high-performance computing , environmental science , systems biology and national security , sometimes in partnership with
8977-400: Is then cooled, typically using water. In the case of a nuclear engine, the water is replaced by hydrogen, but the concept is otherwise similar. Pulsed reactors attempt to transfer the energy directly from the neutrons to the working mass, allowing the exhaust to reach temperatures far beyond the melting point of the reactor core. As specific impulse varies directly with temperature, capturing
9168-688: The Applied Physics Laboratory published their research on nuclear power propulsion and their report was eventually classified. In May 1947, American-educated Chinese scientist Qian Xuesen presented his research on "thermal jets" powered by a porous graphite-moderated nuclear reactor at the Nuclear Science and Engineering Seminars LIV organized by the Massachusetts Institute of Technology . In 1948 and 1949, physicist Leslie Shepherd and rocket scientist Val Cleaver produced
9359-685: The Atomic Energy Commission (AEC) and the National Aeronautics and Space Administration (NASA), and was managed by the Space Nuclear Propulsion Office (SNPO) until the program ended in January 1973. SNPO was led by NASA's Harold Finger and AEC's Milton Klein . NERVA had its origins in Project Rover , an AEC research project at the Los Alamos Scientific Laboratory (LASL) with the initial aim of providing
9550-483: The Atomic Energy Commission (AEC) were more cautious. The Atlas missile program was proceeding well, and if successful would have sufficient range to hit targets in most of the Soviet Union . At the same time, nuclear warheads were becoming smaller, lighter and more powerful. The case for a new technology that promised heavier payloads over longer distances therefore seemed weak. However, the nuclear rocket had acquired
9741-841: The Clinton Engineer Works in 1942 on isolated farm land as part of the Manhattan Project . During World War II, advanced research for the government was managed at the site by the University of Chicago 's Metallurgical Laboratory . In 1943, construction of the Clinton Laboratories, what would later be known as the Oak Ridge National Laboratory, was completed. The site was chosen for the X-10 Graphite Reactor , used to produce plutonium from natural uranium . Enrico Fermi and his colleagues developed
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#17328554601409932-449: The Manhattan Project 's Los Alamos Laboratory where the first atomic bombs were designed, including Stan Ulam , Frederick Reines and Frederic de Hoffmann , speculated about the development of nuclear-powered rockets. In 1946, Ulam and C. J. Everett wrote a paper in which they considered the use of atomic bombs as a means of rocket propulsion. This would become the basis for Project Orion . The public revelation of atomic energy at
10123-411: The Nevada Test Site . While LASL concentrated on reactor development, NASA built and tested complete rocket engines. The AEC, SNPO, and NASA considered NERVA a highly successful program in that it met or exceeded its program goals. It demonstrated that nuclear thermal rocket engines were a feasible and reliable tool for space exploration , and at the end of 1968 SNPO deemed that the latest NERVA engine,
10314-529: The Oak Ridge School of Reactor Technology was established with two courses in reactor operation and safety; almost 1,000 students graduated. Much of the research performed at ORNL in the 1950s was related to nuclear reactors as a form of energy production, both for propulsion and electricity. More reactors were built in the 1950s than in the rest of the ORNL's history combined. One of their most influential projects
10505-530: The Panama Canal Zone , and Antarctica . The US Air Force also contributed funding to three reactors, the lab's first computers, and its first particle accelerators. ORNL built its first molten salt reactor in 1954 as a proof-of-concept for a proposed fleet of long-range bombers , but it was never used. Alvin M. Weinberg was named Director of Research, ORNL, and in 1955 Director of the Laboratory. In
10696-616: The Pewee of Project Rover , were selected in the Mars Design Reference Architecture (DRA). Oak Ridge National Laboratory Oak Ridge National Laboratory ( ORNL ) is a federally funded research and development center in Oak Ridge, Tennessee , United States. Founded in 1943, the laboratory is now sponsored by the United States Department of Energy and administered by UT–Battelle, LLC . Established in 1943, ORNL
10887-648: The Princeton Plasma Physics Laboratory is one such example, although "energy-positive fusion has remained elusive". In 2019, the U.S. Congress approved US$ 125 million in development funding for nuclear thermal propulsion rockets. In May 2022 DARPA issued an RFP for the next phase of their Demonstration Rocket for Agile Cislunar Operations (DRACO) nuclear thermal engine program. This follows on their selection, in 2021, of an early engine design by General Atomics and two spacecraft concepts from Blue Origin and Lockheed Martin . The next phases of
11078-662: The Solar System , to neither of which had the administration committed. Then, on 12 April, the Soviet Union launched Yuri Gagarin into orbit on Vostok 1 , once again demonstrating its technological superiority. A few days later, Kennedy launched the disastrous Bay of Pigs Invasion of Cuba, resulting in yet another humiliation for the United States. On 25 May, he addressed a joint session of Congress . "First," he announced, "I believe that this nation should commit itself to achieving
11269-540: The Spallation Neutron Source (SNS). HFIR provides neutrons in a stable beam resulting from a constant nuclear reaction whereas SNS, a particle accelerator, produces pulses of neutrons. HFIR went critical in 1965 and has been used for materials research and as a major source of medical radioisotopes since. As of 2013, HFIR provides the world's highest constant neutron flux as a result of various upgrades. Berkelium -249, used to synthesize tennessine for
11460-552: The Sputnik crisis , and triggered the Space Race . President Dwight D. Eisenhower responded by creating ARPA to oversee military rocket and technology development, and the National Aeronautics and Space Administration (NASA) to direct civilian rocket development. NASA absorbed NACA as part of its formation, along with several former military programs. NACA had long been interested in nuclear technology. In 1951, it had begun exploring
11651-510: The U.S. Air Force , as part of the NEPA project , by North American Aviation and Douglas Aircraft Company 's Project Rand . These groundbreaking reports identified a reactor engine in which a working fluid of low molecular weight is heated using a nuclear reactor as the most promising form of nuclear propulsion but identified many technical issues that needed to be resolved. In January 1947, not aware of this classified research, engineers of
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#173285546014011842-478: The specific impulse of a chemical engine. In general form, a nuclear engine is similar to a liquid chemical engine. Both hold the working mass in a large tank and pump it to the reaction chamber using a turbopump . The difference is primarily in that the reaction chamber is generally larger, the size of the reactor. Complicating factors were immediately apparent. The first was that a means had to be found of controlling reactor temperature and power output. The second
12033-426: The "open cycle", the losses of nuclear fuel would be difficult to control, which has led to studies of the "closed cycle" or nuclear lightbulb engine, where the gaseous nuclear fuel is contained in a super-high-temperature quartz container, over which the hydrogen flows. The closed-cycle engine has much more in common with the solid-core design, but this time is limited by the critical temperature of quartz instead of
12224-607: The 1960s ORNL was equipped with an IBM 360/91 and an IBM 360/65. In 1995 ORNL bought an Intel Paragon based computer called the Intel Paragon XP/S 150 that performed at 154 gigaFLOPS and ranked third on the TOP500 list of supercomputers. In 2005 Jaguar was built, a Cray XT3 -based system that performed at 25 teraFLOPS and received incremental upgrades up to the XT5 platform that performed at 2.3 petaFLOPS in 2009. It
12415-492: The 330,000-newton (75,000 lbf) Kiwi-B4 nuclear thermal rocket design (with a specific impulse of 825 seconds) as the baseline for the NERVA NRX (NERVA Reactor Experiment). Whereas Kiwi was a proof of concept, NERVA NRX was a prototype of a complete engine. That meant that it would need actuators to turn the drums and start the engine, gimbals to control its movement, a nozzle cooled by liquid hydrogen, and shielding to protect
12606-507: The 60 tests that the SNPO had thought might be required. Unlike other aspects of NERVA, RIFT was solely a NASA responsibility. NASA delegated responsibility for RIFT to Wernher von Braun 's Marshall Space Flight Center (MSFC) in Huntsville, Alabama . Von Braun created a Nuclear Vehicle Projects Office at MSFC, headed by Colonel Scott Fellows, a USAF officer who had worked on ANP. At this time, NASA
12797-494: The AEC held a series of public hearings where emergency cooling requirements were highlighted and the safety requirements became more stringent. Also in 1972, Peter Mazur , a biologist at ORNL, froze with liquid nitrogen , thawed and implanted mouse embryos in a surrogate mother . The mouse pups were born healthy. The technique is popular in the livestock industry, as it allows the embryos of valuable cattle to be transported easily and
12988-569: The Atlantic 3,200 kilometers (2,000 mi) downrange. NERVA would be regarded as mission ready after four successful tests. To support RIFT, LASL established a Rover Flight Safety Office and SNPO created a Rover Flight Safety Panel. Since RIFT called for up to four reactors to fall into the Atlantic Ocean, LASL attempted to determine what would happen when a reactor hit the water at several thousand kilometers per hour. In particular, whether it would go critical or explode when flooded with sea water,
13179-520: The Chinese physicist Hsue-Shen Tsien , and a February 1952 report by engineers at Consolidated Vultee . Bussard's study had little impact at first because only 29 copies were printed, and it was classified as Restricted Data , and therefore could only be read by someone with the required security clearance. In December 1953, it was published in Oak Ridge's Journal of Reactor Science and Technology . The paper
13370-750: The Department of Energy's Oak Ridge reservation: the National Laboratory, the Y-12 National Security Complex , the East Tennessee Technology Park (formerly the Oak Ridge Gaseous Diffusion Plant ), the Oak Ridge Institute for Science and Education , and the developing Oak Ridge Science and Technology Park, although the four other facilities are unrelated to the National Laboratory. The total area of
13561-603: The Earth's atmosphere and perhaps even magnetosphere . The final fission classification is the gas-core engine . This is a modification to the liquid-core design which uses rapid circulation of the fluid to create a toroidal pocket of gaseous uranium fuel in the middle of the reactor, surrounded by hydrogen. In this case, the fuel does not touch the reactor wall at all, so temperatures could reach several tens of thousands of degrees, which would allow specific impulses of 3000 to 5000 seconds (30 to 50 kN·s/kg). In this basic design,
13752-501: The Holifield Heavy Ion Research Facility, a 25 MV particle accelerator , was opened at ORNL. At the time, Holifield had the widest range of ion species and was twice as powerful as other accelerators, attracting hundreds of guest researchers each year. The Department of Energy was concerned with the pollution surrounding ORNL, and it began clean-up efforts. Burial trenches and leaking pipes had contaminated
13943-419: The I sp to between 930 and 1000 seconds. KIWI was the first to be fired, starting in July 1959 with KIWI 1. The reactor was not intended for flight and was named after the flightless bird , Kiwi. The core was simply a stack of uncoated uranium oxide plates onto which the hydrogen was dumped. The thermal output of 70 MW at an exhaust temperature of 2683 K was generated. Two additional tests of
14134-470: The Nuclear Furnace. Work commenced on test facilities at Jackass Flats in mid-1957. All materials and supplies had to be brought in from Las Vegas . Test Cell A consisted of a farm of hydrogen gas bottles and a concrete wall 1 meter (3 ft) thick to protect the electronic instrumentation from radiation produced by the reactor. The control room was located 3.2 kilometers (2 mi) away. The reactor
14325-504: The Nuclear Furnace. Progressively higher power densities culminated in the Pewee. Tests of the improved Pewee 2 design were canceled in 1970 in favor of the lower-cost Nuclear Furnace (NF-1), and the U.S. nuclear rocket program officially ended in the spring of 1973. During this program, the NERVA accumulated over 2 hours of run time, including 28 minutes at full power. The SNPO considered NERVA to be
14516-451: The Nuclear Furnace. Twenty individual engines were tested, with a total of over 17 hours of engine run time. When NASA was formed in 1958, it was given authority over all non-nuclear aspects of the Rover program. To enable cooperation with the AEC and keep classified information compartmentalized, the Space Nuclear Propulsion Office (SNPO) was formed at the same time. The 1961 NERVA program
14707-716: The ORNL Frontier system broke the exascale barrier, achieving 1.102 exaflop/s using 8,730,112 cores. Since 1992 the Center for Computational Sciences has overseen high performance computing at ORNL. It manages the Oak Ridge Leadership Computing Facility that contains the machines. In 2012, Jaguar was upgraded to the XK7 platform, a fundamental change as GPUs are used for the majority of processing, and renamed Titan . Titan performed at 17.59 petaFLOPS and held
14898-538: The Oak Ridge National Lab wrote the first version of Parallel Virtual Machine (PVM), software that enables distributed computing on machines of differing specifications. PVM is free software and has become the de facto standard for distributed computing. Jack Dongarra of ORNL and the University of Tennessee wrote the LINPACK software library and LINPACK benchmarks , used to calculate linear algebra and
15089-412: The Pewee was also built. It was fired several times at 500 MW to test coatings made of zirconium carbide (instead of niobium carbide ) but Pewee also increased the power density of the system. A water-cooled system is known as NF-1 (for Nuclear Furnace ) used Pewee 2's fuel elements for future materials testing, showing a factor of 3 reductions in fuel corrosion still further. Pewee 2 was never tested on
15280-798: The Program for the Development of Space Nuclear Rocket Propulsion (Project Rover)", which they signed on 28 July 1961. SNPO also assumed responsibility for SNAP, Armstrong becoming assistant to the director of the Reactor Development Division at AEC, and Lieutenant Colonel G. M. Anderson, formerly the SNAP project officer in the disbanded ANP Office, became chief of the SNAP Branch in the new division. It soon became apparent that there were considerable cultural differences between NASA and AEC. SNPO Headquarters
15471-589: The Shuttle cargo bay. The design provided 73 kN of thrust and operated at a specific impulse of 875 seconds (8.58 kN·s/kg), and it was planned to increase this to 975 seconds, achieving a mass fraction of about 0.74, compared with 0.86 for the Space Shuttle main engine (SSME). A related design that saw some work, but never made it to the prototype stage, was Dumbo. Dumbo was similar to KIWI/NERVA in concept, but used more advanced construction techniques to lower
15662-575: The Sputnik crisis and a loss of American prestige and influence. In January 1963, Senator Anderson became chairman of the United States Senate Committee on Aeronautical and Space Sciences . He met privately with Kennedy, who agreed to request a supplemental appropriation for RIFT if a "quick fix" to the Kiwi vibration problem that Seaborg promised could be implemented. In the meantime, Finger called
15853-484: The U.S. Rover program intentionally modified a Kiwi reactor (KIWI-TNT) to go prompt critical, resulting in immediate destruction of the reactor pressure vessel, nozzle, and fuel assemblies. Intended to simulate a worst-case scenario of a fall from altitude into the ocean, such as might occur in a booster failure after launch, the resulting release of radiation would have caused fatalities out to 200 m (600 ft) and injuries out to 600 m (2,000 ft). The reactor
16044-605: The US and reduce dependence on foreign oil supplies. There are three key areas of research: electricity, manufacturing and mobility. The electricity division focuses on reducing electricity consumption and finding alternative sources for production. Buildings, which account for 39% of US electricity consumption as of 2012, are a key area of research as the program aims to create affordable, carbon-neutral homes. Research also takes place into higher efficiency solar panels , geothermal electricity and heating , lower cost wind generators , and
16235-555: The US and Russia. The GS&N's work overlaps with that of the Homeland Security Programs Office, providing detection of nuclear material and nonproliferation guidelines. Other areas concerning the Department Homeland Security include nuclear and radiological forensics, chemical and biological agent detection using mass spectrometry , and simulations of potential national hazards. ORNL has been
16426-503: The US-ITER collaboration detailed in 2022. Biological research covers ecology , forestry , genomics , computational biology , structural biology and bioinformatics . The BioEnergy Program aims to improve the efficiency of all stages of the biofuel process to improve the energy security of the United States. The program aims to make genetic improvements to the potential biomass used, formulate methods for refineries that can accept
16617-499: The XE, met the requirements for a human mission to Mars . The program had strong political support from Senators Clinton P. Anderson and Margaret Chase Smith but was cancelled by President Richard Nixon in 1973. Although NERVA engines were built and tested as much as possible with flight-certified components and the engine was deemed ready for integration into a spacecraft, they never flew in space. During World War II , some scientists at
16808-431: The abandonment of plans to build a more powerful NERVA II engine. If more thrust was required, a NERVA I engine could be run longer, or it could be clustered. Nuclear thermal rocket A nuclear thermal rocket ( NTR ) is a type of thermal rocket where the heat from a nuclear reaction replaces the chemical energy of the propellants in a chemical rocket . In an NTR, a working fluid , usually liquid hydrogen ,
16999-485: The attention of John von Neumann , who formed an ad hoc committee for nuclear propulsion of missiles. Mark Mills , the assistant director at Livermore was its chairman, and its other members were Norris Bradbury from LASL; Edward Teller and Herbert York from Livermore; Abe Silverstein , the associate director of the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory ,
17190-436: The basic concept, A1 and A3, added coatings to the plates to test fuel rod concepts. The KIWI B series was fueled by tiny uranium dioxide (UO 2 ) spheres embedded in a low- boron graphite matrix and coated with niobium carbide . Nineteen holes ran the length of the bundles, through which the liquid hydrogen flowed. On the initial firings, immense heat and vibration cracked the fuel bundles. The graphite materials used in
17381-527: The basis of a 2,700 MW design intended to be the upper stage of an ICBM. Nuclear reactors for Project Rover were built at LASL Technical Area 18 (TA-18), also known as the Pajarito Site. The reactors were tested at very low power before being shipped to Jackass Flats in the Nevada Test Site . Testing of fuel elements and other materials science was done by the LASL N Division at TA-46 using several ovens and later
17572-413: The bids. It rated North American's bid as the best bid overall, but Westinghouse and Aerojet had superior bids for the reactor and engine respectively when they were considered separately. After Aerojet promised NASA administrator James E. Webb that it would put its best people on NERVA, Webb spoke to the selection board and told them that although he did not wish to influence their decision, North American
17763-512: The cancellation of the aircraft nuclear propulsion project just as NASA's Plum Brook reactor was nearing completion, and for a time it seemed that NERVA would soon follow. NASA estimated that NERVA would ultimately cost $ 800 million (although AEC reckoned that it would be much less), and the Bureau of the Budget argued that NERVA made sense only in the context of a crewed lunar landing or flights further into
17954-457: The core to remove heat, and the temperature will level off. These opposing effects stabilize the reactivity and a nuclear rocket engine is therefore naturally very stable, and the thrust is easily controlled by varying the hydrogen flow without changing the control drums. NERVA incorporated a radiation shield to protect personnel and external components from the intense neutron and photon radiation it emitted. An efficient lightweight shield material
18145-415: The core. Since it would not be radioactive, it could be safely transported and mated to the lower stages without shielding. In flight, the poison wires would be pulled and the reactor started 121 kilometers (75 mi) above the Atlantic Ocean. The engine would fire for 1,300 seconds, boosting it to an altitude of 480 kilometers (300 mi). It would then be shut down, and the reactor cooled before impacting
18336-687: The design of a nuclear-powered rocket with a solid-core graphite heat exchanger . They reluctantly concluded that although nuclear thermal rockets were essential for deep space exploration, they were not yet technically feasible. In 1953, Robert W. Bussard , a physicist working on the Nuclear Energy for the Propulsion of Aircraft (NEPA) project at the Oak Ridge National Laboratory wrote a detailed study on "Nuclear Energy for Rocket Propulsion". He had read Cleaver and Shepard's work, that of
18527-424: The desired shape. BATH was found to be strong, with a tensile strength of up to 190,000 kilopascals (28,000 psi), capable of withstanding high temperatures, and with superior radiation shielding properties. LASL produced a series of design concepts, each with its own codename: Uncle Tom, Uncle Tung, Bloodhound and Shish. By 1955, it had settled on a 1,500 MW design called Old Black Joe. In 1956, this became
18718-587: The difficulties of dealing with hydrogen, which could leak through microscopic holes that were too small for other fluids to pass through. On 7 November 1961, a minor accident caused a violent hydrogen release. The complex finally became operational in 1964. SNPO envisaged the construction of a 20,000 MW nuclear rocket engine, so Boyer had the Chicago Bridge & Iron Company construct two gigantic 1,900,000-litre (500,000 US gal) cryogenic storage dewars . An engine maintenance and disassembly building (E-MAD)
18909-399: The drums. To increase thrust, it is sufficient to increase the flow of propellant. Hydrogen, whether in pure form or in a compound like ammonia , is an efficient nuclear moderator, and increasing the flow also increases the rate of reactions in the core. This increased reaction rate offsets the cooling provided by the hydrogen. Moreover, as the hydrogen heats up, it expands, so there is less in
19100-463: The early 1960s there was a large push at ORNL to develop nuclear-powered desalination plants, where deserts met the sea, to provide water. The project, called Water for Peace, was backed by John F. Kennedy and Lyndon B. Johnson and was presented at a 1964 United Nations conference, but increases in the cost of construction and falling public confidence in nuclear power caused the plan to be shuttered. The Health Physics Research Reactor built in 1962
19291-468: The economic and environmental feasibility of potential hydro power plants . The Fusion Energy Division pursues short-term goals to develop components such as high-temperature superconductors , high-speed hydrogen pellet injectors, and suitable materials for future fusion research. Much research into the behaviour and maintenance of plasma takes place at the Fusion Energy Division to further
19482-635: The end of the war generated a great deal of speculation, and in the United Kingdom, Val Cleaver , the chief engineer of the rocket division at De Havilland , and Leslie Shepherd , a nuclear physicist at the University of Cambridge , independently considered the problem of nuclear rocket propulsion. They became collaborators, and in a series of papers published in the Journal of the British Interplanetary Society in 1948 and 1949, they outlined
19673-435: The energy of the relativistic neutrons allows for a dramatic increase in performance. To do this, pulsed reactors operate in a series of brief pulses rather than the continual chain reaction of a conventional reactor. The reactor is normally off, allowing it to cool. It is then turned on, along with the cooling system or fuel flow, operating at a very high power level. At this level the core rapidly begins to heat up, so once
19864-399: The engine to be moved in and out on a railroad car. The "Jackass and Western Railroad", as it was light-heartedly described, was said to be the world's shortest and slowest railroad. There were two locomotives, the remotely controlled electric L-1, and the diesel/electric L-2, which was manually controlled but had radiation shielding around the cab . The former was normally used; the latter
20055-457: The engine was restarted, so the Westinghouse engineers rigged a television camera and a vacuum hose, and were able to remove the bird while safely behind a concrete wall. The engine was restarted on 23 June and run at full power for another fourteen and a half minutes. Although there was severe corrosion, resulting in about $ 2.20 of reactivity lost, the engine could still have been restarted, but
20246-470: The engine, payload and crew from radiation. Westinghouse modified the cores to make them more robust for flight conditions. Some research and development was still required. The available temperature sensors were accurate only up to 1,980 K (1,710 °C), far below what was required. New sensors were developed that were accurate to 2,649 K (2,376 °C) , even in a high-radiation environment. Aerojet and Westinghouse attempted to theoretically predict
20437-459: The engineers wanted to examine the core. An hour was now set as the goal for the NRX A6 test. This was beyond the capacity of Test Cell A, so testing now moved to Test Cell C with its giant dewars. NRX A5 was therefore the last test to use Test Cell A. The reactor was started on 7 December 1966, but a shutdown was ordered 75 seconds into the test due to a faulty electrical component. This was followed by
20628-658: The fields listed here. The laboratory's major research areas are described briefly below. The laboratory has a long history of energy research; nuclear reactor experiments have been conducted since the end of World War II in 1945. Because of the availability of reactors and high-performance computing resources, an emphasis on improving the efficiency of nuclear reactors is present. The programs develop more efficient materials, more accurate simulations of aging reactor cores, sensors and controls as well as safety procedures for regulatory authorities. The Energy Efficiency and Electricity Technologies Program aims to improve air quality in
20819-511: The first time, was produced in the HFIR as part of an international effort. HFIR is likely to operate until approximately 2060 before the reactor pressure vessel is considered unsafe for continued use. The SNS has the highest intensity neutron pulses of any human-made neutron source. SNS was made operational in 2006 and has since been upgraded to 1 megawatt with plans to continue up to 3 MW. High-power neutron pulses permit clearer images of
21010-482: The first tokamak to achieve a plasma temperature of 20 million Kelvin. After the success of the fusion experiments, it was enlarged and renamed ORMAK II in 1973; however, the experiments ultimately failed to lead to fusion power plants. The US Atomic Energy Commission (AEC) required improved safety standards in the early 1970s for nuclear reactors, so ORNL staff wrote almost 100 requirements covering many factors including fuel transport and earthquake resistance. In 1972
21201-426: The fuel and cladding. Although less efficient than the open-cycle design, the closed-cycle design is expected to deliver a specific impulse of about 1500 to 2000 seconds (15 to 20 kN·s/kg). The Soviet RD-0410 went through a series of tests at the nuclear test site near Semipalatinsk Test Site . In October 2018, Russia's Keldysh Research Center confirmed a successful ground test of waste heat radiators for
21392-424: The fuel, plutonium-239 , uranium-235 and uranium-233 were considered. Plutonium was rejected because it forms compounds easily and could not reach temperatures as high as those of uranium. Uranium-233 is slightly lighter than uranium-235, releases a higher number of neutrons per fission event on average, and has higher probability of fission, but its radioactive properties make it more difficult to handle, and it
21583-411: The fuels to use is a complex task that has to consider the reaction energy, the mass of the fuel, the mass of the resulting working fluid , and other practical concerns like density and its ability to be easily pumped. Nuclear rocket engines use a nuclear reactor to provide the energy to heat the fuel instead of a chemical reaction. Because nuclear reactions are much more powerful than chemical ones,
21774-404: The goal, before this decade is out, of landing a man on the moon and returning him safely to the earth." He then went on to say: "Secondly, an additional 23 million dollars, together with 7 million dollars already available, will accelerate development of the Rover nuclear rocket. This gives promise of someday providing a means for even more exciting and ambitious exploration of space, perhaps beyond
21965-473: The groundwater beneath the lab, and radiation tanks were sitting idle, full of waste . Estimates of the total cost of clean-up were into the hundreds of millions of US dollars. The five older reactors were subjected to safety reviews in 1987, ordered to be deactivated until the reviews were complete. By 1989 when the High Flux Isotope Reactor was restarted, the US supply of certain medical isotopes
22156-416: The large tanks necessary for liquid hydrogen storage, this means that solid core nuclear thermal engines are best suited for use in orbit outside Earth's gravity well , not to mention avoiding the radioactive contamination that would result from atmospheric use (if an "open-cycle" design was used, as opposed to a lower-performance "closed cycle" design where no radioactive material was allowed to escape with
22347-501: The last technology development reactor required to proceed to flight prototypes. Several other solid-core engines have also been studied to some degree. The Small Nuclear Rocket Engine, or SNRE, was designed at the Los Alamos National Laboratory (LANL) for upper stage use, both on uncrewed launchers and the Space Shuttle . It featured a split-nozzle that could be rotated to the side, allowing it to take up less room in
22538-482: The late 1960s, cuts in funding led to the cancellation of plans for another particle accelerator, and the United States Atomic Energy Commission cut the breeder reactor program by two-thirds, leading to a downsizing in staff from 5,000 to 3,800. In the 1970s, the prospect of fusion power was strongly considered, sparking research at ORNL. A tokamak called ORMAK, made operational in 1971, was
22729-488: The moon, perhaps to the very end of the Solar System itself." The SNPO set an objective for NERVA of 99.7 percent reliability, meaning that the engine would fail to perform as designed no more than three times in every thousand starts. To achieve this, Aerojet and Westinghouse estimated that they would require 6 reactors, 28 engines and 6 reactor in-flight test (RIFT) flights. They planned for 42 tests, considerably fewer than
22920-399: The next highest cross section across all known isotopes. The Am is fissile (because it has an odd number of neutrons ) and has a low critical mass , comparable to that of Pu . It has a very high cross section for fission, and if in a nuclear reactor is destroyed relatively quickly. Another report claims that Am can sustain a chain reaction even as a thin film, and could be used for
23111-404: The nuclear rocket development as head of NASA's Office of Space Reactors. Senator Anderson had doubts about Finger's suitability for the job. He felt that Finger lacked enthusiasm for it. Glenn met with Anderson on 13 April 1959, and convinced him that Finger would do a good job. On 29 August 1960, NASA created the Space Nuclear Propulsion Office (SNPO) to oversee the nuclear rocket project. Finger
23302-734: The number 1 spot on the TOP500 list for November 2012. Other computers include a 77 node cluster to visualise data that the larger machines output in the Exploratory Visualization Environment for Research in Science and Technology (EVEREST), a visualisation room with a 10 by 3 metre (30 by 10 ft) wall that displays 35 megapixel projections. Smoky is an 80 node Linux cluster used for application development. Research projects are refined and tested on Smoky before running on larger machines such as Titan. In 1989 programmers at
23493-574: The only coolant available is the working fluid/propellant. A nuclear solid core engine is the simplest design to construct and is the concept used on all tested NTRs. Using hydrogen as a propellant, a solid core design would typically deliver specific impulses (I sp ) on the order of 850 to 1000 seconds, which is about twice that of liquid hydrogen - oxygen designs such as the Space Shuttle main engine . Other propellants have also been proposed, such as ammonia, water, or LOX , but these propellants would provide reduced exhaust velocity and performance at
23684-452: The other hand, graphite was cheap, actually gets stronger at temperatures up to 3,300 K (3,030 °C), and sublimes rather than melts at 3,900 K (3,630 °C). Graphite was therefore chosen. To control the reactor, the core was surrounded by control drums coated with graphite or beryllium (a neutron moderator) on one side and boron (a neutron poison ) on the other. The reactor's power output could be controlled by rotating
23875-512: The outside, but this would expose the reactor pressure vessel to the maximum operating temperature while adding mass, complexity, and moving parts. An alternative liquid-core design is the nuclear salt-water rocket . In this design, water is the working fluid and also serves as the neutron moderator . Nuclear fuel is not retained, which drastically simplifies the design. However, the rocket would discharge massive quantities of extremely radioactive waste and could only be safely operated well outside
24066-418: The performance of each component. This was then compared to the actual test performance. Over time, the two converged as more was understood. By 1972, the performance of a NERVA engine under most conditions could be accurately forecast. The first test of a NERVA engine was of NERVA A2 on 24 September 1964. Aerojet and Westinghouse cautiously increased the power incrementally, to 2 MW, 570 MW, 940 MW, running for
24257-567: The possibility of acquiring its own nuclear reactor for the aircraft nuclear propulsion (ANP) project, and selected its Lewis Flight Propulsion Laboratory in Ohio to design, build and manage it. A site was chosen at the nearby Plum Brook Ordnance Works, NACA obtained approval from the AEC, and construction of the Plum Brook Reactor commenced in September 1956. Abe Silverstein, the director of Lewis,
24448-534: The preparation of testimony to Congress ." Finger called for bids from industry for the development of the nuclear engine for rocket vehicle application (NERVA) based upon the Kiwi engine developed by LASL. The award was scheduled for 1 March 1961, so that the decision whether or not to proceed could be made by the incoming Kennedy administration . Eight companies submitted bids: Aerojet , Douglas , Glenn L. Martin , Lockheed , North American , Rocketdyne, Thiokol and Westinghouse . A joint NASA–AEC board evaluated
24639-486: The prestigious "National" laboratory designation, until in December 1947, when Union Carbide and Carbon Co. , which already operated two other facilities at Oak Ridge, took control of the laboratory and renamed the site Oak Ridge National Laboratory (ORNL). Post-war, the demand for military science had fallen dramatically, and the future of the lab was uncertain. The X-10 reactor and the laboratory's 1,000 employees were no longer involved in nuclear weapons. Instead, it
24830-547: The program will focus on the design, development, fabrication, and assembly of a nuclear thermal rocket engine. In July 2023, Lockheed Martin was awarded the contract to build the spacecraft and BWX Technologies ( BWXT ) will develop the nuclear reactor. A launch is expected in 2027. Nuclear-powered thermal rockets are more effective than chemical thermal rockets, primarily because they can use low-molecular-mass propellants such as hydrogen. As thermal rockets, nuclear thermal rockets work almost exactly like chemical rockets :
25021-556: The project no longer had a military purpose. Responsibility for the non-nuclear components of Project Rover was officially transferred from the United States Air Force (USAF) to NASA on 1 October 1958, the day NASA officially became operational and assumed responsibility for the US civilian space program. Project Rover became a joint NASA–AEC project. Silverstein, whom Glennan had brought to Washington, DC, to organise NASA's spaceflight program, appointed Harold Finger to oversee
25212-490: The pulsed mode but could vary their duty cycle depending on the need. For instance, during a high-thrust phase of flight, like exiting a low earth orbit , the engine could operate continually and provide an Isp similar to that of traditional solid-core design. But during a long-duration cruise, the engine would switch to pulsed mode to make better use of its fuel. Liquid core nuclear engines are fueled by compounds of fissionable elements in liquid phase . A liquid-core engine
25403-502: The reactor was automatically started and briefly run at full power with no vibration problems. This was followed by the Kiwi B4E test on 28 August in which the reactor was operated for twelve minutes, eight of which were at full power. On 10 September, Kiwi B4E was restarted, and run at full power for two and a half minutes, demonstrating the ability of a nuclear rocket engine to be shut down and restarted. In September, tests were conducted with
25594-567: The reactor's construction were resistant to high temperatures but eroded under the stream of superheated hydrogen, a reducing agent . The fuel species was later switched to uranium carbide , with the last engine run in 1964. The fuel bundle erosion and cracking problems were improved but never completely solved, despite promising materials work at the Argonne National Laboratory . NERVA NRX (Nuclear Rocket Experimental), started testing in September 1964. The final engine in this series
25785-460: The relationship was between Project Rover and Apollo. Finger replied that it was an insurance policy, and could be used in the later Apollo or post-Apollo missions, such as a base on the Moon or a mission to Mars. Wiesner, supported by Brown and Hornig, argued that if a Mars mission could not occur before the 1980s, then RIFT could be postponed to the 1970s. Seamans noted that such an attitude had resulted in
25976-588: The reservation is 150 square kilometres (58 sq mi) of which the lab takes up 18 square kilometres (7 sq mi). In 1934 the Freel Farm Mound Site , an archaeological site and burial mound of the Late Woodland period was excavated. The site is currently inundated by Melton Hill Lake . The city of Oak Ridge was established by the Army Corps of Engineers as part of
26167-422: The rocket propellant. ) One way to increase the working temperature of the reactor is to change the nuclear fuel elements. This is the basis of the particle-bed reactor, which is fueled by several (typically spherical) elements that "float" inside the hydrogen working fluid. Spinning the entire engine could prevent the fuel element from being ejected out the nozzle. This design is thought to be capable of increasing
26358-472: The role of de facto construction manager, with the AEC officials reporting directly to him. In August 1961, the Soviet Union ended the nuclear test moratorium that had been in place since November 1958, so Kennedy resumed US nuclear weapons testing in September. With a second crash program at the Nevada Test site, labor became scarce, and there was a strike. When that ended, the workers had to come to grips with
26549-526: The same as the Saturn V; the Saturn C-5N mission configuration would be larger still, at 120 meters (393 ft) tall, but the 160-meter (525 ft) Vehicle Assembly Building (VAB) could easily accommodate it. It would consist of an S-IC first stage, a dummy S-II middle stage filled with water, and an S-N (Saturn-Nuclear) NERVA upper stage. For an actual mission, a real S-II stage would be used. The S-N stage
26740-424: The series, Kiwi B1B on 1 September 1962, resulted in extreme structural damage to the reactor, fuel module components being ejected as it was ramped up to full power. A subsequent full-power Kiwi B4A test on 30 November 1962, along with a series of cold flow tests, revealed that the problem was vibrations that were induced when the hydrogen was heated as the reactor was being brought up to full power rather than when it
26931-451: The site of various supercomputers , home to the fastest on several occasions. In 1953, ORNL partnered with the Argonne National Laboratory to build ORACLE (Oak Ridge Automatic Computer and Logical Engine), a computer to research nuclear physics, chemistry, biology, and engineering. ORACLE had 2048 words (80 Kibit ) of memory and took approximately 590 microseconds to perform addition or multiplication of integers. In
27122-480: The specific impulse to about 1000 seconds (9.8 kN·s/kg) at the cost of increased complexity. Such a design could share design elements with a pebble-bed reactor , several of which are currently generating electricity. From 1987 through 1991, the Strategic Defense Initiative (SDI) Office funded Project Timberwind , a non-rotating nuclear thermal rocket based on particle bed technology. The project
27313-681: The square root of the kinetic energy loaded on each unit mass of propellant. The kinetic energy per molecule of propellant is determined by the temperature of the heat source (whether it be a nuclear reactor or a chemical reaction ). At any particular temperature, lightweight propellant molecules carry just as much kinetic energy as heavier propellant molecules and therefore have more kinetic energy per unit mass. This makes low-molecular-mass propellants more effective than high-molecular-mass propellants. Because chemical rockets and nuclear rockets are made from refractory solid materials, they are both limited to operate below 3,000 °C (5,000 °F), by
27504-454: The stand and became the basis for current NTR designs being researched at NASA 's Glenn Research Center and Marshall Space flight Center. The NERVA/Rover project was eventually canceled in 1972 with the general wind-down of NASA in the post- Apollo era. Without a human mission to Mars , the need for a nuclear thermal rocket is unclear. Another problem would be public concerns about safety and radioactive contamination . In January 1965,
27695-420: The state of Tennessee , universities and other industries. ORNL has several of the world's top supercomputers , including Frontier , ranked by the TOP500 as the world's most powerful. The lab is a leading neutron and nuclear power research facility that includes the Spallation Neutron Source , the High Flux Isotope Reactor , and the Center for Nanophase Materials Sciences . Oak Ridge National Laboratory
27886-480: The strength characteristics of high-temperature metals. Chemical rockets use the most readily available propellant, which is waste products from the chemical reactions producing their heat energy. Most liquid-fueled chemical rockets use either hydrogen or hydrocarbon combustion, and the propellant is therefore mainly water (molecular mass 18) and carbon dioxide (molecular mass 44). Nuclear thermal rockets using gaseous hydrogen propellant (molecular mass 2) therefore have
28077-430: The targets, meaning smaller samples can be analysed and accurate results require fewer pulses. Between 2002 and 2008 ORNL partnered with Caterpillar Inc. to form a new material for their diesel engines that can withstand large temperature fluctuations. The new steel, named CF8C Plus, is based on conventional CF8C stainless steel with added manganese and nitrogen ; the result has better high–temperature properties and
28268-446: The turbopump was used to keep the power steady at 40 MW. It worked perfectly. The computer simulations had been correct, and the whole project was ahead of schedule. The next test was of NERVA A3 on 23 April 1965. This test was intended to verify that the engine could be run and restarted at full power. The engine was operated for eight minutes, three and a half of them at full power, before the instruments indicated that too much hydrogen
28459-420: The type of reactor, ranging from a relatively simple solid reactor up to the much more difficult to construct but theoretically more efficient gas core reactor. As with all thermal rocket designs, the specific impulse produced is proportional to the square root of the temperature to which the working fluid (reaction mass) is heated. To extract maximum efficiency, the temperature must be as high as possible. For
28650-479: The understanding of plasma physics , a crucial area for developing a fusion power plant. The US ITER office is at ORNL with partners at Princeton Plasma Physics Laboratory and Savannah River National Laboratory . The US contribution to the ITER project is 9.1% which is expected to be in excess of US$ 1.6 billion throughout the contract. ORNL researchers participated in developing of an extensive research plan for
28841-419: The use of liquid hydrogen as the fuel for the upper stages. In a 1960 paper, Schmidt proposed replacing the upper stages with nuclear NERVA stages. This would deliver the same performance as Nova, but for half the cost. He estimated the cost of putting a pound of payload into lunar orbit as $ 1,600 for an all-chemical Saturn, $ 1,100 for Nova, and $ 700 for a chemical-nuclear Saturn. MSFC issued a study contract for
29032-405: The weight of the reactor. The Dumbo reactor consisted of several large barrel-like tubes, which were in turn constructed of stacked plates of corrugated material. The corrugations were lined up so that the resulting stack had channels running from the inside to the outside. Some of these channels were filled with uranium fuel, others with a moderator, and some were left open as a gas channel. Hydrogen
29223-463: The world's second self-sustaining nuclear reactor after Fermi's previous experiment, the Chicago Pile-1 . The X-10 was the first reactor designed for continuous operation. After the end of World War II, management of the lab was contracted by the US government to Monsanto ; however, they withdrew in 1947. The University of Chicago temporarily re-assumed responsibility, with the site receiving
29414-506: Was added. It had thick concrete walls and shield bays where engines could be assembled and disassembled. There was also an engine test stand (ETS-1); two more were planned. In March 1963, SNPO and MSFC commissioned Space Technology Laboratories (STL) to produce a report on what kind of nuclear rocket engine would be required for possible missions between 1975 and 1990. These missions included early crewed planetary interplanetary round-trip expeditions (EMPIRE), planetary swingbys and flybys, and
29605-605: Was an international effort: three electromagnets were produced in the US, one in Japan, one in Switzerland and the final by remaining European states. ORNL was involved in analysing the damage to the core of the Three Mile Island Nuclear Generating Station after the accident in 1979 . The 1980s brought more changes to ORNL: a focus on efficiency became paramount. An accelerated climate simulation chamber
29796-593: Was appointed as its manager, with Milton Klein from AEC as his deputy. Finger was also the Director of Nuclear Systems in the NASA Office of Advanced Research and Technology. A formal "Agreement Between NASA and AEC on Management of Nuclear Rocket Engine Contracts" was signed by NASA Deputy Administrator Robert Seamans and AEC General Manager Alvin Luedecke on 1 February 1961. This was followed by an "Inter-Agency Agreement on
29987-536: Was assigned responsibility for the development of the nuclear ramjet , which was codenamed Project Pluto . Project Rover was directed by an active duty United States Air Force (USAF) officer seconded to the AEC, Lieutenant Colonel Harold R. Schmidt. He was answerable to another seconded USAF officer, Colonel Jack L. Armstrong, who was also in charge of Pluto and the Systems for Nuclear Auxiliary Power (SNAP) projects. Rocket engines create thrust by accelerating
30178-614: Was built that applied varying weather conditions to insulation to test its efficacy and durability faster than real time. Materials research into heat resistant ceramics for use in truck and high-tech car engines was performed, building upon the materials research that began in the nuclear reactors of the 1950s. In 1987 the High Temperature Materials Laboratory was established, where ORNL and industry researchers cooperated on ceramic and alloy projects. The materials research budget at ORNL doubled after initial uncertainty regarding Reagan's economic policy of less government expenditure. In 1981,
30369-407: Was canceled before testing. In a conventional solid core design, the maximum exhaust temperature of the working mass is that of the reactor, and in practice, lower than that. That temperature represents an energy far below that of the individual neutrons released by the fission reactions. Their energy is spread out through the reactor mass, causing it to thermalize. In power plant designs, the core
30560-761: Was co-located with AEC Headquarters in Germantown, Maryland . Finger established branch offices at Albuquerque, New Mexico , (SNPO-A) to liaise with LASL, and in Cleveland, Ohio , (SNPO-C) to coordinate with the Lewis Research Center, which was activated in October 1961. In February 1962, NASA announced the establishment of the Nuclear Rocket Development Station (NRDS) at Jackass Flats, and in June an SNPO branch
30751-426: Was considered a success as a proof of concept for nuclear rocket engines. It demonstrated that hydrogen could be heated in a nuclear reactor to the temperatures required for space propulsion and that the reactor could be controlled. The next step was the Kiwi B series of tests, which commenced with Kiwi B1A on 7 December 1961. This was a development of the Kiwi A engine, with a series of improvements. The second test in
30942-408: Was deeply committed to Project Apollo , and the board might consider combining other bids. On 8 June, Webb announced that Aerojet and Westinghouse had been selected. Aerojet became the prime contractor, with Westinghouse as the principal subcontractor. Both companies recruited aggressively, and by 1963, Westinghouse had 1,100 staff working on NERVA. In March 1961, President John F. Kennedy announced
31133-968: Was depleted. In 1989 the former executive officer of the American Association for the Advancement of Science , Alvin Trivelpiece , became director of ORNL; he remained in the role until 2000. In 1992 whistleblower Charles Varnadore filed complaints against ORNL, alleging safety violations and retaliation by his superiors. While an administrative law judge ruled in Varnadore's favor, Secretary of Labor Robert Reich overturned that ruling. However, Varnadore's case saw prime contractor Martin Marietta cited for safety violations and ultimately led to additional whistleblower protection within DOE. In January 2019 ORNL announced
31324-482: Was developed by the Aerojet Nuclear Systems Company from a mixture of boron carbide ( B 4 C ), aluminum and titanium hydride ( TiH 2 ), known as BATH after its components. Titanium hydride is an excellent neutron moderator and boron carbide an excellent neutron absorber. The three components were mixed in powdered form and a commercial extrusion machine was used to extrude them into
31515-466: Was engaged in planning for the lunar landing mission that Kennedy had called for. In the process the agency considered several booster concepts, including what became the Saturn family and the larger Nova . These were chemical rockets, although nuclear upper stages were also considered for Nova. The December 1959 Silverstein Committee had defined the configuration of the Saturn launch vehicle, including
31706-487: Was established at Las Vegas (SNPO-N) to manage it. By the end of 1963, there were 13 NASA personnel at SNPO Headquarters, 59 at SNPO-C and 30 at SNPO-N. SNPO staff were a combination of NASA and AEC employees whose responsibilities included "program and resource planning and evaluation, the justification and distribution of program resources, the definition and control of overall program requirements, monitoring and reporting of progress and problems to NASA and AEC management, and
31897-453: Was going into the engine. A scram was ordered, but a coolant line became clogged. Power increased to 1,165 MW before the line unclogged, and the engine shut down gracefully. There were fears for the integrity of the tie rods that held the fuel clusters together. They were supposed to operate at 473 K (200 °C), with a maximum of 651 K (378 °C). The sensors recorded that the tie rods had reached 1,095 K (822 °C), which
32088-480: Was intended to lead to the entry of nuclear thermal rocket engines into space exploration. Unlike the AEC work, which was intended to study the reactor design itself, NERVA's goal was to produce a real engine that could be deployed on space missions. The 334 kN (75,000 lb f ) thrust baseline NERVA design was based on the KIWI B4 series. Tested engines included Kiwi, Phoebus, NRX/EST, NRX/XE, Pewee, Pewee 2, and
32279-602: Was judged sufficient for space missions by SNPO. Building on the KIWI series, the Phoebus series were much larger reactors. The first 1A test in June 1965 ran for over 10 minutes at 1090 MW and an exhaust temperature of 2370 K. The B run in February 1967 improved this to 1500 MW for 30 minutes. The final 2A test in June 1968 ran for over 12 minutes at 4000 MW, at the time the most powerful nuclear reactor ever built. A smaller version of KIWI,
32470-539: Was named after the New Zealand kiwi bird. A kiwi cannot fly, and the Kiwi rocket engines were not intended to do so either. Their function was to verify the design, and test the behavior of the materials used. The Kiwi program developed a series of non-flyable test nuclear engines, the primary focus being to improve the technology of hydrogen-cooled reactors. In the Kiwi A series of tests conducted between July 1959 and October 1960, three reactors were built and tested. Kiwi A
32661-408: Was not readily available. Uranium-235 was therefore chosen. For structural materials in the reactor, the choice came down to graphite or metal. Of the metals, tungsten emerged as the front runner, but it was expensive, hard to fabricate, and had undesirable neutronic properties. To get around its neutronic properties, it was suggested tungsten-184 , which does not absorb neutrons, should be used. On
32852-520: Was particularly eager to acquire control of Project Rover. Donald A. Quarles , the Deputy Secretary of Defense , met with T. Keith Glennan , the new administrator of NASA , and Hugh Dryden , Glennan's deputy on 20 August 1958, the day they after Glennan and Dryden were sworn into office at the White House , and Rover was the first item on the agenda. Quarles was eager to transfer Rover to NASA, as
33043-569: Was positioned on a railroad car in the Jackass Flats area of the Nevada Test Site . As of January 2012, the propulsion group for Project Icarus was studying an NTR propulsion system, but has seen little activity since 2019. In 1987, Ronen & Leibson published a study on applications of Am (one of the isotopes of americium ) as nuclear fuel to space nuclear reactors , noting its extremely high thermal cross section and energy density . Nuclear systems powered by Am require less fuel by
33234-526: Was proceeding well, and the need for a nuclear upper stage had all but disappeared. On 2 October 1957, the AEC proposed cutting its budget. Two days later, the Soviet Union launched Sputnik 1 , the first artificial satellite. This surprise success fired fears and imaginations around the world. It demonstrated that the Soviet Union had the capability to deliver nuclear weapons over intercontinental distances, and contested cherished American notions of military, economic and technological superiority. This precipitated
33425-511: Was provided as a backup. Construction workers were housed in Mercury, Nevada . Later thirty mobile homes were brought to Jackass Flats to create a village named "Boyerville" after the supervisor, Keith Boyer. Construction work was completed in the fall of 1958. NASA planned to develop a community of 2,700 people, with 800 dwellings and their own shopping complex by 1967. By 1957, the Atlas missile project
33616-402: Was pumped into the middle of the tube and would be heated by the fuel as it traveled through the channels as it worked its way to the outside. The resulting system was lighter than a conventional design for any particular amount of fuel. Between 1987 and 1991, an advanced engine design was studied under Project Timberwind , under the Strategic Defense Initiative , which was later expanded into
33807-483: Was recognised as the world's fastest from November 2009 until November 2010. Summit was built for Oak Ridge National Laboratory during 2018, which benchmarked at 122.3 petaFLOPS. As of June 2020, Summit was the world's second fastest [clocked] supercomputer with 202,752 CPU cores, 27,648 Nvidia Tesla GPUs , and 250 Petabytes of storage, having lost the top position to the Japanese Fugaku supercomputer. In May 2022,
33998-479: Was reported by the Karlsruhe Institute of Technology 2008 study. In 2000, Carlo Rubbia at CERN further extended the work by Ronen and Chapline on a Fission-fragment rocket using Am as a fuel. Project 242 based on Rubbia design studied a concept of Am based Thin-Film Fission Fragment Heated NTR by using a direct conversion of the kinetic energy of fission fragments into increasing of enthalpy of
34189-404: Was run at intermediate power levels on 3 and 11 February, with a full power (1,055 MW) test on 3 March, followed by engine duration tests on 16 and 25 March. The engine was started eleven times. All test objectives were successfully accomplished, and NRX/EST operated for a total of nearly two hours, including 28 minutes at full power. It exceeded the operating time of previous Kiwi reactors by nearly
34380-400: Was running at full power. Unlike a chemical engine that would likely have blown up after suffering catastrophic damage, the nuclear rocket engine remained stable and controllable even when tested to destruction. The tests demonstrated that a nuclear rocket engine would be rugged and reliable in space. Kennedy visited LASL on 7 December 1962 for a briefing on Project Rover. It was the first time
34571-410: Was shut down for various reasons, including to focus on Space Shuttle development. Although more than ten reactors of varying power output have been built and tested, as of 2024 , no nuclear thermal rocket has flown. Whereas all early applications for nuclear thermal rocket propulsion used fission processes, research in the 2010s has moved to fusion approaches. The Direct Fusion Drive project at
34762-454: Was still classified, as was the journal, but this gave it a wider circulation. Darol Froman , the deputy director of the Los Alamos Scientific Laboratory (LASL), and Herbert York , the director of the University of California Radiation Laboratory at Livermore , were interested and established committees to investigate nuclear rocket propulsion. Froman brought Bussard out to LASL to assist for one week per month. Bussard's study also attracted
34953-458: Was test fired with its plume in the air so that radioactive products could be safely dissipated. The reactor maintenance and disassembly building (R-MAD) was in most respects a typical hot cell used by the nuclear industry, with thick concrete walls, lead glass viewing windows, and remote manipulation arms. It was exceptional only for its size: 76 meters (250 ft) long, 43 meters (140 ft) wide and 19 meters (63 ft) high. This allowed
35144-409: Was that a means had to be devised to hold the propellant. The only practical means of storing hydrogen was in liquid form, and this required temperatures below 20 K (−253.2 °C ). The third was that the hydrogen would be heated to a temperature of around 2,500 K (2,230 °C), and materials were required that could both withstand such temperatures and resist corrosion by hydrogen. For
35335-593: Was the light-water reactor , a precursor to many modern nuclear power stations. The US Military funded much of its development, for nuclear-powered submarines and ships of the US Navy . The US Army also contracted the design of portable nuclear reactors in 1953 for heat and electricity generation in remote military bases. The reactors were produced by the American Locomotive Company and used in Greenland ,
35526-537: Was the XE, designed with flight representative hardware and fired into a low-pressure chamber to simulate a vacuum. SNPO fired NERVA NRX/XE twenty-eight times in March 1968. The series all generated 1100 MW, and many of the tests concluded only when the test-stand ran out of hydrogen propellant. NERVA NRX/XE produced the baseline 334 kN (75,000 lb f ) thrust that Marshall Space Flight Center required in Mars mission plans. The last NRX firing lost 17 kg (38 lb) of nuclear fuel in 2 hours of testing, which
35717-534: Was the maximum that the sensors could record. Laboratory tests later confirmed that the rods might have reached 1,370 K (1,100 °C). There was also what appeared to be a hole in the nozzle, but this turned out to be soot. The robust engine was undamaged, so the test continued, and the engine was run for thirteen minutes at 1,072 MW. Once again, the test time was limited only by the available hydrogen. Testing of NASA's NERVA NRX/EST (Engine System Test) commenced on 3 February 1966. The objectives were: The NRX/EST
35908-433: Was then continued through the NASA's NERVA program (1961–1973). NERVA achieved many successes and improved upon the early prototypes to create powerful engines that were several times more efficient than chemical counterparts. However, the program was cancelled in 1973 due to budget constraints. To date no nuclear thermal propulsion system has ever been implemented in space. A nuclear thermal rocket can be categorized by
36099-456: Was to be built by Lockheed in a dirigible hangar NASA acquired at Moffet Field in Sunnyvale, California , and assembled at NASA's Mississippi Test Facility . The SNPO planned to build ten S-N stages, six for ground tests and four for flight tests. Launches were to take place from Cape Canaveral . NERVA engines would be transported by road in shockproof, watertight containers, with the control rods locked in place and nuclear poison wires in
36290-430: Was used for radiation exposure experiments leading to more accurate dosage limits and dosimeters , and improved radiation shielding . In 1964 the Molten-Salt Reactor Experiment began with the construction of the reactor. It operated from 1966 until 1969 (with six months down time to move from U-235 to U-233 fuel) and proved the viability of molten salt reactors , while also producing fuel for other reactors as
36481-483: Was used for scientific research. In 1946 the first medical isotopes were produced in the X-10 reactor, and by 1950 almost 20,000 samples had been shipped to various hospitals. The quantity and variety of radionuclides produced by X-10 for medicine grew steadily in the 1950s. ORNL was the only Western source of californium-252 . ORNL scientists also performed the world's first successful bone marrow transplant in mice by suppressing their immune systems . In 1950
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