"Discovering how radiation does what it does to inorganic, organic, and living matter will benefit the entire world," declared biochemist Waldo Cohn as he speculated about the Laboratory's postwar research agenda.
The dilemma facing the Laboratory in the years following World War II was how to obtain the means to pursue such research. After all, the Laboratory's brief history had been devoted largely to supporting development of the atomic bomb. Although scientists had touted peaceful applications of the atom, there were no assurances that the government would be willingor ableto shift its administrative gears and resources to support such research.
One answer to the Laboratory's postwar research dilemma came from an unexpected source: investigations into nuclear-powered aircraft sponsored by the AEC and partially funded by the U.S. Air Force. The plane never got off the ground, but the research directed toward this effort lifted to new heights scientific knowledge in biology, chemistry, and physics and, at the same time, led to new advances in technologies related to reactors, computers, and accelerators. (See related article, Small Science in a Big Laboratory.)
In the long run, spin-offs from research into atomic travelin funding for biology, medicine, genetics, and computer sciencewould prove more useful than the primary research goal itself.
FLIGHTS OF FANCY
Fantasies about future applications of atomic power abounded just after World War II. Popular writing and art, which depicted atomic-powered ships, submarines, aircraft, trains, automobiles, and even farm tractors, stimulated public interest. These popular images came into sharp focus at Oak Ridge, where the Laboratory participated in development of nuclear-powered submarines, aircraft, and ships during the late 1940s and 1950s.
The application of atomic power to motion and travel became a centerpiece of the Laboratory's research program in the postwar era, and efforts to devise nuclear-powered transport, especially aircraft and submarines, involved many Laboratory researchers. This research, in turn, contributed to the design of three nuclear reactors, the adoption of high-speed digital computers, and the acquisition of particle accelerators for nuclear physics. Moreover, the efforts fueled the Laboratory's budget and staffing, both of which increased during the late 1940s and early 1950s under the management of its new contract operator, Union Carbide Corporation.
In February 1950, the Laboratory merged with the research divisions at the Y-12 Planta move that strengthened and diversified the Laboratory's research efforts. One direct result of this merger was a set of projects designed to build reactor-driven machines that could travel over land, work underwater, and perhaps even fly. In the process, the Laboratory hoped to turn the public's postwar atomic dreams into concrete demonstrations of atomic energy's potential contributions to society.
Acquiring the Y-12 Plant's research divisions increased Laboratory staff by 50% and, by 1953, more than 3600 people were employed at the newly merged facilities. Moreover, the merger enabled the Laboratory to acquire divisions with strong capabilities in applied science and heavy industrial technology. The Laboratory also benefited from the transfer of state-of-the-art hardware, such as cyclotrons that could accelerate subatomic particles to unprecedented speeds.
Added responsibilities, personnel, and equipment created new challenges in Laboratory management and administration. In late 1947, Union Carbide Corporation's Carbide & Carbon Chemical Company, later renamed the Union Carbide Corporation Nuclear Division, became the Laboratory's operations contractor. It enjoyed two advantages that would serve both the company and the Laboratory well.
First, the company's expertise in chemical engineering fit the tasks it would be asked to accomplish. Second, Union Carbide was no stranger to Oak Ridge. Since 1943, it had managed a large staff that operated the K-25 Plant. In 1947, the government extended Union Carbide's responsibilities to the Y-12 Plant's production facilities. Thus, when the AEC called on Union Carbide to oversee Laboratory research activities in December 1947, it placed all Oak Ridge operations under unified management.
Union Carbide soon proved its mettle both to the AEC and Laboratory personnel. Under the arrangement, Carbide executivesboth at the corporation's international headquarters in New York City and at its regional headquarters in Oak Ridgeset Laboratory work rules and pay scales. Virtually the entire Laboratory staff went on Union Carbide's payroll. For its services, Union Carbide received a fixed fee from the AEC that amounted to less than 2% of the Laboratory's annual budget.
Union Carbide appointed Nelson Rucker as the Laboratory's director until a permanent director could be found. A graduate of Virginia Military Institute, Rucker joined Union Carbide in 1933 to manage a Carbide plant in West Virginia. He moved to Oak Ridge with Carbide in the early 1940s and remained there throughout the war. At the time of his appointment to the position of Laboratory executive director, he was serving as the Y-12 Plant's manager.
Rucker was responsible for overseeing the Laboratory's daily activities. Playing a role comparable to that of a city manager, he saw that the institution functioned efficiently on a day-to-day basis, but he did not set its technical agenda. Union Carbide had as much difficulty filling the position of director in the late 1940s as the University of Chicago had had a few years earlier. Several prominent scientists, including John Dunning, rejected the position. In December 1948, Carbide asked Alvin Weinberg to become director. He also declined, citing his youth and lack of experience, but agreed to become the associate director for research and development.
A biophysicist, Alvin Weinberg had studied the fission of living cells at the University of Chicago during the late 1930s. In 1941, he joined the Metallurgical Project to investigate nuclear fission. As an assistant to Eugene Wigner, he participated in wartime reactor designs. In May 1945, on Wigner's advice, he moved to Oak Ridge to join the Laboratory's Physics Division, where he succeeded Lothar Nordheim as division chief in 1947. Weinberg, whose ability to communicate his thoughts in writing was exceeded only by his rare scientific talent, captured both the spirit of excitement and that of confusion that existed at the Laboratory during the late 1940s when he wrote Wigner about his responsibilities as head of the Physics Division. "I feel in my new job a little bit like a trick horseback rider at a circus," Weinberg told Wigner. "The idea seems to be to ride standing on three or four spirited horses, all of which are interested in going in different directions." (See related article, Director Alvin Weinberg: Mr. ORNL.)
Limited work space constituted a major challenge facing Rucker, Weinberg, and other Laboratory managers in the late 1940s. During the postwar turmoil, the AEC suspended new construction and often deferred maintenance on existing structures, pending the government's decision on the Laboratory's future. This wait-and-see attitude, which made sense given the uncertainties in Washington, continued while wartime frame structures swiftly deteriorated. The only new facilities erected at the Laboratory between 1946 and 1948 were surplus Army quonset huts to relieve overcrowding, plus an electric substation and steam power plant constructed in futile anticipation that the proposed Materials Testing Reactor would be built in Oak Ridge.
Overcrowding became serious in 1948 as the Laboratory added new divisions, hired more personnel, and installed new equipment. These events led physicist Gale Young to complain, "In accumulating technical people which it cannot use for lack of accommodations, I believe that the Laboratory has embarked on a course which is suicidal to itself and detrimental to the national interest. Until considerably more buildings have been erected, staff reductions, rather than increases, are in order."
In 1949, with the Laboratory's future on a firmer, more stable footing, the AEC budgeted $20 million for new construction, and Union Carbide initiated its "Program H" to replace wooden wartime structures with more permanent brick and mortar. In addition to paving of streets, landscaping of grounds, and renovation of older structures, about 250,000 square feet of new office and laboratory space opened in the early 1950s. Among the new facilities, three were of particular importance: Building 4500, the Laboratory's principal research building and administrative headquarters; a radioisotope complex consisting of 10 buildings designed to process, package, and ship the Laboratory's most valuable material exports; and a pilot plant for use in chemical processing. With this new construction, the AEC and Union Carbide gradually hoisted the Laboratory out of the East Tennessee mud.
The AEC's 1947 decision to centralize reactor development at Argonne National Laboratory proved ill-considered. Argonne's mandate from the AEC to support Navy reactor development and new programs for civilian power and breeder reactors strained its resources and capabilities. As a result, it supported Oak Ridge's efforts to continue design and fabrication work in East Tennessee to free its staff to concentrate on its own full plate of responsibilities in Chicago.
Taking advantage of this unexpected turn of events, in 1948 Oak Ridge urged the AEC to build the Materials Testing Reactor on the Cumberland Plateau, 20 miles from Oak Ridge. The AEC, however, acquired a site in Idaho and, four years later, the newly built Materials Testing Reactor at the Idaho National Engineering Laboratory began successful operation under the supervision of Richard Doan, formerly the research director at Oak Ridge. Two years before the reactor in Idaho began operation, however, the Laboratory had the world's first solid-fuel and light-water reactor operating in Oak Ridge. Despite the government's intentions to end reactor work at the Laboratory, the facility's deeply rooted efforts in development of this technology refused to wither.
While designing the Materials Testing Reactor in 1948, the Laboratory built a small mock-up of the reactor to investigate the design of its controls and hydraulic systems. In 1949, Weinberg proposed installing uranium fuel plates inside the mock-up to test the reactor design under critical conditions. The AEC staff feared that Weinberg's initiative might become an opening wedge for a revived reactor program at Oak Ridge. "We have no plans," Weinberg reassured them, "to convert the critical experiment into a reactor." In February 1950, the mock-up experiment at Oak Ridge produced the first visible blue Cerenkov glow of a nuclear reaction underwater, and it provided superb training for those who were to serve subsequently as operators for the full-scale reactor in Idaho.
As its reactor program burgeoned, the AEC relaxed its previous plans to centralize reactor development and construction at Argonne National Laboratory and Idaho National Engineering Laboratory. In fact, the AEC allowed the Laboratory to upgrade the mock-up's shielding and cooling systems. These improvements raised the system's capacity to 3000 thermal kilowatts, only one-tenth of the Materials Testing Reactor's maximum power but still useful for experiments.
Labeled the "poor man's pile" by Wigner, the mock-up formally became the Low Intensity Test Reactor (LITR). Experiments conducted at the LITR established the feasibility of the boiling-water reactor, which later became one of the design prototypes for commercial nuclear power plants. Operated remotely from the Graphite Reactor control room, the "poor man's pile" served the Laboratory until 1968 when the AEC shut it down after a long, useful life.
With funds drawn largely from the U.S. Air Force, the Laboratory's major entrance into reactor development during the 1950s came through efforts to design a nuclear airplane. British and German development of jet engines at the end of World War II had given quick, defensive fighters an advantage over slower long-range offensive bombers. To address the imbalance, General Curtis LeMay and Colonel Donald Keirn, both of the Air Force, urged development of nuclear-powered bombers. In 1946, they persuaded General Groves to approve Air Force use of the vacated S-50 plant near the K-25 Plant in Oak Ridge to investigate whether nuclear energy could propel aircraft.
The initial concept called for a nuclear- propelled bomber that could fly at least 12,000 miles at 450 miles per hour without refueling. Such range and speed would enable nuclear weapons to be delivered via airborne bombers anywhere in the world. The aircraft, however, would require a compact reactor small enough to fit inside a bomber and powerful enough to lift the airplane into the air, complete with lightweight shielding to protect the crew from radiation.
Under Air Force contract, the Fairchild Engine and Airplane Corporation then established a task force at the S-50 plant to examine the feasibility of nuclear aircraft and arranged with Wigner to receive scientific support from the Laboratory. Initial studies conducted by the Fairchild Corporation at the S-50 plant showed promise and, in 1948, the AEC asked the Massachusetts Institute of Technology (MIT) to evaluate the feasibility of nuclear-powered flight. MIT sent scientists to Lexington, Massachusetts, for a summer's appraisal, and they reported that such flight could be achieved within 15 years if sufficient resources were applied to the effort. In September 1949, the AEC approved Laboratory participation in an aircraft nuclear propulsion project. Weinberg was made project director and Cecil Ellis coordinator. Raymond Briant, Sylvan Cromer, and Walter Jordan later served as directors of the Laboratory's Aircraft Nuclear Propulsion (ANP) project.
Soon after the Laboratory acquired its nuclear propulsion project, General Electric took over the work of Fairchild and relocated it from Oak Ridge to its plant in Ohio. Although some Fairchild personnel transferred to Ohio, about 180 remained in Oak Ridge to join the Laboratory's aircraft project in May 1951. Among those who decided to stay in East Tennessee were Francois Kertesz, a multilingual scientist; Edward Bettis, a computer wizard before the age of computers; William Ergen, a reactor physicist; Fred Maienschein, later the director of the Laboratory's Engineering Physics and Mathematics Division; and Don Cowen of the Laboratory's Information and Reports Division.
Much of the Laboratory's initial aircraft work focused on development of lightweight shielding to protect airplane crews and aircraft rubber, plastic, and petroleum components from radiation. Knowing a nuclear aircraft would never become airborne carrying the thick walls typical of reactor shields, Everitt Blizard and his team worked two shifts daily, testing potential lightweight shielding materials in the lid tank atop the Graphite Reactor. As research progressed, however, the Graphite Reactor proved inadequate to meet the level of research activity. To continue its shielding investigations, the Laboratory added two unique nuclear reactors to its fleet.
First, in December 1950, the Laboratory completed its 2-MW Bulk Shielding Reactor at a cost of only $250,000. To build this reactor, the Laboratory modified its earlier Materials Testing Reactor design to create what became popularly known as the "swimming pool" reactor. This reactor's enriched uranium core was submerged in water for both core cooling and neutron moderation. From an overhead crane, the reactor could be moved about a concrete tank, the size of a swimming pool, to test bulk shielding in various configurations. A 10-kW nuclear assembly (named the Pool Critical Assembly) was subsequently placed in a corner of the pool to permit small-scale experiments without tying up the larger reactor.
The Laboratory standardized this inexpensive, safe, and stable design, which became a prototype for many research reactors built at universities and private laboratories around the world. Upgraded with a forced cooling system in 1963, it supplanted the Graphite Reactor (retired that year) and proved extremely useful for irradiation and study of materials at low temperatures.
A second Laboratory reactor resulting from the nuclear aircraft project was the Tower Shielding Facility, completed in 1953. Cables from steel towers could hoist a 1-MW reactor in a spherical container nearly 200 feet (60 meters) into the air. Because no shielding surrounded the reactor when suspended, it operated under television surveillance from an underground control room.
Containing uranium and aluminum fuel plates moderated and cooled by water, this reactor helped scientists answer questions about radiation from a reactor flying overhead; it also helped researchers better understand the type and amount of shielding that would be needed aboard a nuclear aircraft.
Experiments indicated that a divided shield, consisting of one section around the aircraft's reactor and another around its crew, would comprise a combined weight less than that of a single thick shield blanketing the aircraft's reactor. Researchers, however, could never devise a reactor and shielding light enough to ensure safe flight. They even considered a "tug-tow" arrangement in which the crew and controls would be in a towed glider, separated from, yet tied to, the reactor by a long umbilical cable. The Tower Shielding Facility reactor later was upgraded, and shielding experiments recently took place there in support of breeder reactor development, long after visions of a nuclear aircraft faded from memory.
The Bulk Shielding Reactor and Tower Shielding Facility were designed to test materials that might be used on a nuclear-powered aircraft. For the U.S. Air Force, improved materials represented a means toward an end: a nuclear-powered engine that could drive long-range bombers to takeoff speeds and propel them around the world. To achieve this goal, the Laboratory designed an experimental 100-kW aircraft reactor as a demonstration.
This small reactor, operating at high temperatures, used molten uranium salts as its fuel, which flowed in serpentine tubes through an 18-inch (46-centimeter) reactor core. A heat exchanger dissipated the reactor's heat into the atmosphere. In 1953, the Laboratory constructed a building to house this experimental reactor.
To contain molten salts at high temperatures within a reactor, the Laboratory used a nickel-molybdenum alloy, INOR-8, designed by Oak Ridge researchers and fabricated at the International Nickel Company. Able to resist corrosion at high temperatures while retaining acceptable welding properties, the alloy was commercialized as Hastelloy-N by private industry (an early example of technology transfer) to supply tubing, sheet, and bar stock for industrial applications. The aircraft reactor also compelled Laboratory personnel to learn how to perform welding with remote manipulators and how to remotely disassemble molten-salt pumps. In addition, Laboratory researchers also devised two salt reprocessing schemes to recover uranium and lithium-7 from spent reactor fuel.
The first test run of the Aircraft Reactor Experiment took place in October 1954. The reactor ran at 1 MW for 100 hours. Don Trauger and other observers of the reactor's operations recall that the reactor core, pumps, valves, and components literally became red hot. Completing the design, fabrication, and operation of such an exotic nuclear reactor in five years was considered a noteworthy event, and dignitaries such as General James Doolittle, Admiral Lewis Strauss, and Captain Hyman Rickover visited Oak Ridge to see the red-hot reactor in action.
Its success led the Laboratory to propose additional study of this reactor concept and the design of a larger 60-MW, spherical prototype, known as the "fireball reactor," to conduct more sophisticated experiments. Laboratory researchers, for example, asked what would happen if an airplane turned upside down while irradiated molten liquid pulsated through the engine. More significantly, they wondered what would happen if the plane failed in midair or during takeoff or landing.
Three unique reactors were not the only hardware the Laboratory acquired as a result of its nuclear aircraft project. The project helped justify construction of a critical experiments facility to test reactor fuels and a physics laboratory to study the effects of radiation on solid materials. It also advanced Laboratory efforts to acquire its first nuclear particle accelerators and digital computers.
Because the success of nuclear flight depended on expensive and complex hardware on the ground, the Laboratory benefited from being on the receiving end of a well-funded government project. However, the Laboratory's ability to take advantage of this situation also depended on the skill of its research and support staff and the managerial expertise of its leaders. Internal administrative adjustments, including the merger of the Y-12 Plant's research division with the Laboratory, also helped.
ORNL'S Y-12 LABORATORIES
By 1950, all partiesthe government, the Laboratory, and the companylargely viewed Carbide's management of the Laboratory as a success. Recognizing that staff loyalties resided with the Laboratory, Carbide did not attempt to convert them to "company personnel." It eagerly identified and rewarded ambitious Laboratory staff (elevating some to managerial positions), undertook sorely needed facility reconstruction and expansion, and fostered basic and applied sciences. "Carbide management has demonstrated, "asserted one manager, "that first-rate basic research can be done in an industrial framework."
When Nelson Rucker, Carbide's executive director of Laboratory operations, transferred to a plant in West Virginia in 1950, a major reorganization ensued. Alvin Weinberg, formerly associate director, became the Laboratory's research director, and Clarence Larson, formerly the Y-12 Plant manager, became the Laboratory's new director. (See related article, Clarence Larson: The Right Chemistry.)
A chemist from Minnesota, Larson had worked at the University of California's radiation laboratory before moving to Oak Ridge to become the Y-12 Plant research director in 1943 and superintendent in 1948. An able manager and accomplished scientist, Larson strengthened and broadened the Laboratory's research activities.
Before Larson's appointment, Union Carbide considered moving the Laboratory to the Y-12 Plant, where the Biology Division already occupied a building. By 1950, however, the chilling tensions of the Cold War and the heated battles of the Korean War sparked rapid expansion of nuclear weapons production, which increased the workload at the Y-12 and K-25 plants and led to construction of new gaseous diffusion plants at Paducah, Kentucky, and Portsmouth, Ohio. As a result, space became precious at the Y-12 Plant, and plans to move the Laboratory there were aborted. Thus, the Laboratory's acquisition of the Y-12 Plant's three research divisionsIsotope Research and Production, Electromagnetic Research, and Chemical Researchleft everyone and everything in the same place. However, as a result of the administrative realignment, Y-12 Plant researchers in these divisions began reporting to Laboratory management.
By 1950, the Laboratory was distributing more than 50 different radioisotopes to qualified research centers. Cobalt-60, used for cancer research and therapy, was a prime isotope on the Laboratory's distribution list. When the Laboratory began to ship isotopes overseas, the AEC approved a cooperative arrangement between the Laboratory and the Oak Ridge Institute of Nuclear Studies to train foreign scientists in radioisotope research.
The Laboratory's isotope research efforts were further advanced through the merger of the Y-12 Plant's Isotope Research and Production Division with the Laboratory's Isotopes Division. This union added stable, non radioactive isotopes to the Laboratory's catalog.
The Y-12 Plant's stable-isotopes program had emerged at the end of the war when Y-12 staff ceased separating uranium isotopes for atomic weapons. Eugene Wigner then urged continued use of some calutrons to separate the stable isotopes of all elements. "We should have as the very basis of future work in nuclear physics and chemistry knowledge of the various cross sections of pure stable isotopes," he urged. The AEC approved Wigner's proposal, and a group led by Clarence Larson, Christopher Keim, and Leon Love began to separate various isotopes of stable elements.
Researchers at first used four calutrons salvaged from electromagnetic equipment. Stable-isotope research and development required modifications to the calutrons, better understanding of the obscure chemistry of less common elements, spectroscopic analysis of nuclear properties, and advances in the use of isotopes as tracers.
Christopher Keim, a group leader, later recalled that copper isotopes were the first to be collected. Using enriched copper-65 as the source material for neutron irradiation, George Boyd, John Swartout, and colleagues positively identified nickel-65 as a nickel isotope with a half-life of 2.6 hours. This discovery represented the first use of calutron-separated stable isotopes in research. "All that had to be done," Keim modestly explained, "was to put copper chloride into the charge bottle, heat it with uranium tetrachloride, lower the magnetic field, and space the collector slots to receive the copper-63 and copper-65 ion beams."
Stable isotopes of iron, platinum, lithium, and mercury, for example, were separated and shipped to university, government, and industrial laboratories worldwide to aid basic research in physics, chemistry, earth sciences, biology, and biomedicine. They became especially valuable to medical science, for which they were converted into radionuclides used as tracers to diagnose cancer, heart disorders, and other diseases affecting human internal organs and bones. Contributing to basic scientific knowledge and enhancing the quality of human life, the Laboratory's stable isotopes program continued to expand through the 1970s. At its height, the program generated more than $1 million annually in sales revenue.
In 1950, the Y-12 Plant's Electromagnetic Research Division, under Robert Livingston, became the Laboratory's Electronuclear Division, switching from studies of calutrons to fundamental research on the formation and motion of ions in electric fields. The Electronuclear Division was also in charge of the cyclotrons used for particle acceleration. At the same time, Arthur Snell and colleagues in the Physics Division entered the particle acceleration field as well, using electrostatic accelerators.
Thus the Laboratory, during the early 1950s, pursued two independent lines of particle accelerationcyclotrons in the Electronuclear Division and electrostatic accelerators in the Physics Division. This hot pursuit of fast-moving subatomic particles was propelled by rapid postwar advances in the basic science of nuclear physics.
During the postwar years, exploration of the unknown particles and forces of atomic nuclei led to the discovery of subatomic particles smaller than neutrons, electrons, and protons. The study of these elementary particles emerged from nuclear science as a subfield labeled high-energy physics. Oak Ridge, as a national laboratory dedicated to fundamental research, was anxious to participate in subatomic explorations.
Its research efforts had an abortive start in 1946, however, when the Laboratory proposed to purchase a large betatron accelerator to join the hunt for elusive subatomic particles. This purchase required approval by the Army, and the resulting bureaucratic delays made the 160-ton betatron obsolete when it finally arrived. Saddled with an outdated piece of equipment, the Laboratory sold it as surplus to another government agency. By 1948, however, the Laboratory's nuclear aircraft program, with support from the U.S. Air Force, was inching down the runway. This project added impetus to accelerator research because of the need to understand the effects of radiation on shields and other materials that would be part of the aircraft.
In 1948, Arthur Snell, director of the Physics Division, asked Wilfred Good and Charles Moak to start an accelerator program using materials readily and inexpensively available at the Laboratory and the Y-12 Plant. "The objective was clear," recalled Good. "Neutrons were the key to the new frontier of applied nuclear energy; to fully exploit neutrons, their behavior had to be thoroughly understood; and the Van de Graaff accelerator was the only known source of neutrons of precisely determined energies." The Chemistry Division had acquired a 2.5-MV Van de Graaff electron accelerator from the Navy. Richard Lamphere of the Instrumentation and Controls Division converted it into a 3-MV proton accelerator that could bombard lithium targets with protons to produce a stream of neutrons. This little Van de Graaff accelerator supported research for 30 years, its most important service to science coming when John Gibbons, Richard Macklin, and colleagues used it to confirm a theory that atomic elements originated through nucleosynthesis in the centers of stars.
To test radiation effects at energies lower than those generated by the Van de Graaff accelerator, the Laboratory also acquired a Cockcroft-Walton accelerator, an early particle accelerator named for its inventors. The Laboratory installed these first accelerators in an abandoned powerhouse.
In March 1949, Alvin Weinberg and Herman Roth of the AEC met Air Force commanders and contractors to discuss priorities in the nuclear aircraft research program. After concluding that a 5-MV Van de Graaff accelerator was needed, the Air Force agreed to purchase it if the Laboratory would construct a building to house it. First installed at the Y-12 Plant, the 5-MV Van de Graaff accelerator produced its first beam in 1951, making it the world's highest energy machine of its kind. In 1952, the Laboratory completed the building for the High Voltage Laboratory and moved the three electrostatic particle accelerators into it. A decade later, it added a 6-MV tandem Van de Graaff accelerator to extend the energy capability of the existing machines and to accelerate ions heavier than helium. Thirty years later, Laboratory physicists still view this accelerator as a valuable research tool.
While Arthur Snell and members of the Laboratory's Physics Division concentrated on particle acceleration through direct-current high-voltage machines, Robert Livingston and the Y-12 Plant's electromagnetic team pursued an independent course of achieving acceleration with cyclotrons. Invented in 1930 by Ernest Lawrence at Berkeley, cyclotrons had two D-shaped electrodes (dees) in a large and nearly uniform magnetic field.
The dees operated at high electric potential and were alternately positive or negative. They accelerated the charged particles (ions), and the magnetic field confined them to a circular orbit.
Cyclotrons were the forerunners of the giant synchrotrons of the 1990s, and during their 60 years of development, they increased the energy of protons (nuclei of hydrogen atoms) from one million electron volts to 20 trillion electron volts. The cost of the machines also multiplied from $100,000 each to $10 billion each.
Having built calutrons during the war for electromagnetic separation of uranium isotopes, Livingston and his associates at the Y-12 Plant had abundant experience and took advantage of the unused electromagnets left over from the war effort. During the late 1940s and early 1950s, they built three cyclotrons to study the properties of compound nuclei and heavy particle reactions. The cyclotrons were identified by their diameters measured across the dees as 22-inch, 63-inch, and 86-inch machines.
Livingston's team built the 22-inch cyclotron in the late 1940s to test how electromagnets in calutrons could be used and how high-current calutron ion-source techniques could be applied to cyclotron functioning. The cyclotron served its purpose, and its size was later doubled to 44 inches for testing new ion sources, new beam-focusing methods, and new ways to increase the intensities of accelerated beams.
The 86-inch cyclotron began operation in November 1950 and was used to perform radiation damage studies for the nuclear aircraft project. As the world's largest fixed-frequency proton cyclotron, it produced a proton beam four times more intense than any other cyclotron; its blue beam projected through the air as much as 16 feet (5 meters), visibly impressing visitors.
Bernard Cohen, chief physicist for this machine, used it to study proton-induced nuclear reactions and to supply the isotope polonium-208 until a commercial source became available.
This was the era of hydrogen bomb development, and the question arose whether a powerful hydrogen bomb might ignite nitrogen in the atmosphere, causing a worldwide holocaust. To find the answer, the AEC asked the Laboratory to build a cyclotron that would accelerate nitrogen ions to determine the probability that they would react with each other at hydrogen-bomb temperatures to produce carbon, oxygen, and enormous amounts of energy. The Laboratory asked Alex Zucker, a newly minted Ph.D. from Yale University, to develop a source of multiply charged nitrogen ions. After successfully completing this task, he was directed to build a cyclotron to measure the cross section of the nitrogen-nitrogen reaction and thereby determine whether the atmosphere would burn.
Built in 18 months at a cost of $300,000, the cyclotron became operational in 1952. Zucker and his collaborators, Harry Reynolds and Dan Scott, soon demonstrated that a hydrogen bomb would not ignite a giant chain reaction that would immolate the earth. They then turned the cyclotron into a basic research instrument, the world's first source of energetic heavy ions, making the interactions of complex nuclei a new field of scientific investigation.
The Laboratory's first cyclotrons were the most economical ones ever built because the Electronuclear Division used surplus electromagnetic equipment that required little modification. Because the Y-12 Plant's calutron tracks had been placed side by side in vertical formation, the Laboratory's cyclotrons were marked by their unique vertical mounting instead of the horizontal position of the dees found at other laboratories. These pioneering cyclotrons helped advance the technology of high-beam currents, and they have since been the force behind the Laboratory's versatile Oak Ridge Isochronous Cyclotron completed in 1962 and still later the Holifield Heavy Ion Research Facility completed in 1980.
The aircraft nuclear propulsion project, together with the reactors and particle accelerators developed to support it, generated immense quantities of scientific data that required rapid analysis. This need stimulated Laboratory interest in electronic computers, which became available during the 1940s.
In 1947, Weinberg created a Mathematics and Computing Section within the Physics Division under the direction of Alston Householder, a mathematical biophysicist from the University of Chicago, who in 1948 converted the section into an independent Mathematics Panel to manage the Laboratory's acquisition of computers.
Before 1948, complex, multifaceted computations at the Y-12 and K-25 plants were done on electric calculators and card programming machines. Because of its participation in the nuclear aircraft project, the Laboratory obtained a matrix multiplier to solve linear equations. At the Laboratory's urging, the AEC also leased Harvard University's early Mark I computer. Householder and Weinberg insisted that the Laboratory should also acquire its own "automatic sequencing computer" to be used by staff scientists doing difficult computations for the nuclear aircraft project. The computer, they contended, could also serve to educate university faculty and researchers visiting the Laboratory. When purchased, it became the first electronic digital computer in the South.
Householder and the Laboratory's leadership were familiar with the pioneering work of Wigner's friend, John von Neumann, who had pursued experimental computer development near the end of the war for the Navy. Admiral Lewis Strauss thought the Navy needed computers to aid in weather forecasting, vital to ships at sea. With his urging, the Navy in 1946 sponsored fabrication of the first von Neumann digital computer at Princeton University. After considering Raytheon and other commercial computers, the Laboratory and Argonne National Laboratory decided to build their own von Neumann-type computers, tailored specifically to solve nuclear physics problems. Laboratory engineers assisted Argonne during the early 1950s in design and fabrication of the Oak Ridge Automatic Computer and Logical Engine. Its name was selected with reference to a lyrical acronym from Greek mythologyORACLE, defined as "a shrine in which a deity reveals hidden knowledge."
Assembled before the development of transistors and microchips, the ORACLE was a large scientific digital computer that used vacuum tubes. It had an original storage capacity of 1024 words of 40 bits each (later doubled to 2048 words). The computer also contained a magnetic-tape auxiliary memory and an on-line cathode-tube plotter, a recorder, and a typewriter. Operational in 1954, for a time the ORACLE had the fastest speed and largest data storage capacity of any computer in the world. Problems that would have required two mathematicians with electric calculators three years to solve could be done on the ORACLE in 20 minutes.
Householder and the Mathematics Panel used the ORACLE to analyze radiation and shielding problems. In 1957, Hezz Stringfield and Ward Foster, both of the Budget Office, also adopted the ORACLE for more mundane but equally important tasksannual budgeting and monthly financial accounting. As one of the last "homemade computers," the ORACLE became obsolete by the 1960s. The Laboratory then purchased or leased its mainframe computers from commercial suppliers. From the initial applications of the ORACLE to nuclear aircraft problems, computer enthusiasm spread like lightning throughout the Laboratory, and in time, use of the machines became common in all the Laboratory's divisions.
Scintillation spectrometers and multichannel analyzers were other machines that benefited fromand contributed tothe Laboratory's involvement with the nuclear aircraft project and its related studies of atomic particle behavior and radiation damage.
In 1947, German scientists observed that some crystals emitted flashes of light when struck by radiation beams and that the intensity of the flash was proportional to the radiation's energy. By 1950, a scientific team at the Laboratory led by P. R. Bell devised an improved scintillation spectrometer to measure the number and intensity of light flashes emanating from crystals exposed to radiation. Electronic recording of these measured flashes by multichannel analyzers permitted complete and rapid analysis of particle and gamma-ray energies. (See related article, P. R. Bell: Scanning the Future.)
Bell's group later converted the scintillation spectrometer into a medical pulse analyzer and developed a "scintiscanner" and an electronic probe to assist physicians using radioisotopes to locate tumors without surgery. In 1956, Bell's team received funding from the AEC to continue this work, and they formed a Medical Instruments Group in the Laboratory's Thermonuclear Division at the Y-12 Plant, where they primarily investigated fusion energy. Later, they incorporated electronic computers in medical scanners to improve diagnostic techniques. Commercial versions of the machines they invented became common at major medical centers throughout the world.
Prolonged exposure to radiation often alters the properties of solid materials and compromises their structural integrity. Thus, the success of the Laboratory's nuclear airplane project depended in part on understanding the potential impact of radiation on solid materials. This understanding was essential in determining how to protect materials from radiation and in developing new materials that were radiation-resistant. Such concerns lifted the importance of solid-state research throughout the Laboratory in the early 1950s. (See related article, Radiation Effects in Materials: Cultivated at Oak Ridge.)
The first step towards a Solid State Division was taken in 1950 when a Physics of Solids Institute was established under the direction of Douglas Billington. Formed by joining the Solid State Section of the Physics Division with the Radiation and Physical Metallurgy Section of the Metallurgy Division, institute researchers occupied a new laboratory built south of the Graphite Reactor. In 1952, the institute became the Solid State Division, and its primary mission was to obtain basic scientific knowledge about radiation damage processes in materials.
"Inasmuch as a thorough understanding of the normal behavior of solids is necessary for a complete understanding of effects induced by nuclear radiation in metals and other solids," Billington declared, "studies in related solid-state fields are being carried out in conjunction with the radiation effects experiments." One notable discovery, made by Mark Robinson and Ordean Oen, was the theoretical prediction of the "ion channeling" phenomenon, in which charged particles move undisturbed for long distances between the layers of atoms in a solid. This prediction was quickly followed by experimental programs at laboratories throughout the world, including ORNL, to study the channeling effect and to use it in research involving ion scattering and ion implantation.
Because research showed that some radiation-induced defects in metals move at room temperatures and below, it was necessary to produce these defects in samples at very low temperatures and to study them while they were "frozen-in" at the low temperatures. Such experiments, which were a tour de force for the Laboratory, were performed first at the Graphite Reactor and later at the Bulk Shielding Reactor by Tom Blewitt, Ralph Coltman, Tom Noggle, Charles Klabunde, and Jean Redman. The samples were placed in or very close to the reactor core. To keep the samples at low temperatures as the reactor operated, refrigerators with extreme cooling capabilities were required; fortunately large refrigerators that had been built for early work on the hydrogen bomb had become surplus and were available for this work. Sample temperatures down to 3 degrees Kelvin were ultimately obtained, and experiments in which the samples' dimensional changed, electrical resistivity, and stored energy were measured provided very important information on defect production by radiation and on defect removal as the samples temperatures were raised.
Important early radiation damage investigations on semiconductor materials were performed by Jim Crawford, John Cleland, and J. C. Pigg. The electrical properties of semiconductors are very sensitive to small numbers of defects, and these experiments were an important tool in establishing models of radiation damage and in understanding the changes in electrical properties caused by defects. Other important early radiation damage investigations included experiments by Fred Young, Jr., and Leslie Jenkins to study the chemical properties of metal surfaces. These experiments determined the effects of radiation on various chemical processes, such as oxidation. Results from the various radiation-damage experiments were important to the nuclear airplane project and to other types of reactor programs throughout the world, and members of the Solid State Division quickly gained international recognition for their research.
Researchers in the Biology Division shared a concern for radiation effects. Their focus was not inert solid materials but living cells. The nuclear plane project boosted this research as well, because calculating the sensitivity of cells to radiation would help determine the amount of shielding that would be necessary to protect passengers from potential radiation. This knowledge, in turn would have a direct effect on the design of the airplane.
Like so many other aspects of the nuclear plane project, this research had ramifications beyond its immediate goals. For example, Laboratory biologists learned that nucleoproteins, present in living cell nuclei and essential to normal cell functioning, are sensitive to ionizing radiation. Paper chromatography and ion-exchange methods used to separate compounds, Laboratory researchers reasoned, could help scientists and medical researchers measure and gauge this sensitivity.
After applying ion-exchange chromatography to separation of fission products and starting the Laboratory's radioisotopes program, Waldo Cohn used the same technique to separate and identify the constituents of nucleic acids. From this work came the discovery with Elliott Volkin that ribonucleic acid (RNA) has the same general structure as deoxyribonucleic acid (DNA), a concept that had a fundamental impact on molecular biology, virology, and genetics.
OF MICE AND MAMMALS
By 1949, 10,000 mice were housed in ORNL's renovated facilities at the Y-12 Plant. Research on mice, led by the Biology Division's William and Liane Russell, was designed to advance understanding of radiation effects on mammals. (See related article, The Russells: A Family Affair.)
According to William Russell, mice are used for genetic studies because they have few diseases, can be fed and maintained economically, reproduce rapidly, and have the same essential organs as humans. Liane Russell's 1950 survey of the gestation period of mice to examine their sensitivity to radiation yielded valuable information about critical periods during embryo development. She showed that radiation-induced changes of cells were more likely to occur during gestation. Largely because of her discovery of the greater radiation sensitivity of embryos, women have been cautioned about X-ray examinations during pregnancies.
The Russells, a cosmopolitan husband and wife team from England and Austria, came to Oak Ridge in 1948 from Bar Harbor, Maine. They expected Oak Ridge to be a backward community with minimal social and cultural opportunities. The Biology Division had an international clientele, however, and Liane Russell was surprised by the extent to which the world beat a path to Oak Ridge and the Laboratory. The Russells became renowned for taking their international guests on mountain hiking trails. They later played key roles in the creation of the Big South Fork National River Recreation Area, a wilderness preserve just north of Oak Ridge.
Just as the Biology Division had an international reputation, the Oak Ridge School of Reactor Technology (ORSORT) established in 1950 enjoyed national prestige. ORSORT was the reestablished version of the original reactor training school of 1946-47. Because reactor technology was security sensitive and could not be taught in universities, the AEC, with considerable support from Captain Rickover and the Navy, sponsored this school for outstanding engineers and scientists. (See related article, Rickover: Setting the Nuclear Navy's Course.)
Frederick VonderLage, the school's first director, was a former Navy officer who had taught physics at the Naval Academy. The faculty included Laboratory staff, and the school's text consultant was Samuel Glasstone, who published several overviews of nuclear reactor technology.
The 50 members of the school's first class in 1950 came from the AEC, government contractors, and the armed services; the second class came largely from industries needing personnel trained in reactor engineering and operations; later, college graduates planning to work in the nuclear industry were accepted. Students took courses in reactor technology that covered reactor neutron physics, radiation damage, reactor materials, chemical separations processes, and experimental reactor engineering. They spent a year in Oak Ridge and supplemented their classroom training with part-time research assignments at the Laboratory. After two semesters, students would load fuel into the movable assembly in the Bulk Shielding Reactor, plotting the power output curve as fuel was added and the flux increased. They then compared the onset of critical mass with their predictions. Later, they spent a summer investigating specific problems, often analyzing a reactor design under consideration by the AEC and then submitting a thesis on its feasibility.
The school expanded during the 1950s, occupying a new building completed by the Laboratory in 1952 and specializing in advanced subjects not taught at universities. Under director Lewis Nelson, the school in 1957 joined six universities in offering a standard two-year curriculum. At the end of the decade, the first international students enrolled. Five years later, the school closed when university science and engineering programs became equal to the task of providing this type of specialized instruction. Of its 986 enrollees during the school's 15 years of instruction, only 10 did not complete the course. Some of its graduates became leaders in the nuclear industry.
When Union Carbide assumed management of the Laboratory, the Graphite Reactor was the only nuclear reactor on the Oak Ridge Reservation. By 1953, the Laboratory had three reactors operating, two nearing completion, and others in various stages of planning and development. In addition, it had high-speed computers, high-energy cyclotrons, and Van de Graaff particle accelerators. Equally important, the Laboratory had succeeded in assembling an aggressive research staff that worked with a sense of urgency rivaling that of the war years.
As the Laboratory expanded its reactor and shielding programs in response to the nuclear aircraft project and acquired the Y-12 Plant's research organization in the early 1950s, administrative realignment became necessary. Electronics experts from the Physics Division, for example, moved into an Instrumentation and Controls Division, and the Shielding group became a separate Neutron Physics Division (renamed the Engineering Physics Division, and later the Engineering Physics and Mathematics Division). The Mathematics Section also became an independent division. Similar organizational changes took place in chemistry, reactor technology, and other Laboratory research pursuits.
By 1953, Laboratory personnel numbered 3600, more than double the wartime peak; the staff was divided into 15 research and operating divisions. "I am sometimes appalled by the size and scope of our operation here," Weinberg admitted privately to Wigner. "It seems that we have become willy-nilly victims, in a particularly devastating way, of the big operator malady."
In response, Wigner advised Weinberg to appoint deputy and assistant directors to assist central management. Weinberg accepted the advice. John Swartout, director of the Chemistry Division, became Weinberg's assistant director in 1950 and deputy director in 1955. For administrative functions, Swartout became "Mr. Inside," while Weinberg was "Mr. Outside." Other assistant directors of the early 1950s included Elwood Shipley, Charles Winters, Robert Charpie, Walter Jordan, Mansell Ramsey, Ellison Taylor, and George Boyd.
"There is," observed Weinberg, "a hierarchy of responsibility in which management on each level depends on the integrity and sense of responsibility of the next level to do the job sensibly and well." This line of responsibility from individual to group leader to section chief to division director to assistant or associate director to Laboratory director remained the prevailing administrative framework within the Laboratory during the ensuing decades. (See related article, Democratic Responsibility.)
The prime force behind Laboratory expansion during the early 1950s ended in 1957, when Congress objected to continuing the costly nuclear aircraft project in the face of supersonic aircraft and ballistic missile development that made the nuclear aircraft concept obsolete.
In response to this congressional decision, the Laboratory shelved its aircraft shielding and reactor prototype investigations. In 1961, President John Kennedy canceled the remainder of the nuclear aircraft project.
The scientific data gleaned from the aircraft project, however, soon proved useful when the Laboratory undertook the design of a molten-salt reactor for electric power production. William Manly, a veteran of the nuclear aircraft program, later pointed out that the knowledge gained in handling liquid metals and fused salts also proved useful in design of nuclear generators and reactors for use in space. As Laboratory metallurgist George Adamson summarized it, "The program quite literally didn't get off the ground, but out of it grew the base for the high-temperature materials technology needed by NASA and in several industrial fields."
Although the nuclear aircraft project stalled, the Laboratory's participation in efforts to apply nuclear energy to vehicle propulsion continued briefly in consultation with the Maritime Commission, which in 1957 built a nuclear-powered merchant ship. The 21,000-ton ship, propelled by a pressurized-water reactor, was a floating laboratory, demonstrating the feasibility of commercial ships propelled by nuclear energy. At the Laboratory, a Maritime Reactors group headed by Alfred Boch provided technical review of the ship reactor design, while other Laboratory units assisted with on-board health monitoring, environmental studies, and waste disposal.
Completed in July 1959, the N.S. Savannah could remain at sea for 300,000 miles without refueling, proving the scientific and engineering feasibility of such ships. Nuclear-powered ships, however, could not compete economically with oil-fired vessels; thus, the N.S. Savannah became the first and last U.S. ship of its kind.
In the 1960s, the Laboratory became involved in nuclear power studies for the national space program, and in the 1980s it studied space reactors for the Strategic Defense Initiative. Despite these efforts, it is fair to say that the Laboratory's work on the N.S. Savannah marked the end of its nuclear transportation programs. Postwar dreams of nuclear-powered trains, automobiles, aircraft, and tractors ended, but the scientific findings that evolved from these endeavors would find applications in other areas in the years ahead.
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