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A symbol of peaceful competition first in the ancient world and then in the 20th century, the Olympics were revived after World War I, not only in quadrennial athletic performances but also in scientific competitions. Sparked in 1953 by President Dwight Eisenhower's call for international cooperation in the peaceful uses of atomic energy, in 1955 and 1958 scientists worldwide showcased their achievements at international conferences that resembled the athletic Olympics. In these competitions, the world-class research at Oak Ridge National Laboratory often took the laurels.
Science during the 1950s became a full-blown instrument of foreign policy, both in Cold War weapons competition and in peaceful applications of nuclear science, especially nuclear fission reactors and fusion energy devices. As an international center for nuclear fission research by the mid-1950s, the Laboratory had as many as six reactors under design or construction. The Laboratory's chemical technology expertise also made it a leader in reactor fuel reprocessing and recovery. Both these programs earned the Laboratory much prestige at the 1955 scientific olympics. Also, in 1958, the Laboratory's tiny fusion energy research effort vaulted above larger programs elsewhere to win the gold at the second United Nations Conference on Peaceful Uses of Atomic Energy. The Laboratory and other AEC facilities also embarked on a program of experimental reactor development in 1953. That year, the Laboratory's experimental homogeneous reactor, under Samuel Beall's direction, first generated electric power. Elsewhere, other nuclear mileposts were passed: a demonstration atomic reactor to propel submarines and an experimental breeder reactor began operating in Idaho, and the first university research reactor was unveiled at North Carolina State University. In a dramatic speech on the future of the atom to the United Nations in 1953, President Eisenhower pledged the United States "to find the way by which the miraculous inventiveness of man shall not be dedicated to his death, but consecrated to his life." The president's "Atoms for Peace" speech, hailed throughout the world as a prologue to a new chapter in the history of nuclear energy, was to guide the research efforts of the AEC and the Laboratory for years to come. The initiative, Alvin Weinberg declared, would make nuclear science the "touchstone of peace." Soon after this address, President Eisenhower signed the 1954 Atomic Energy Act, which fostered the cooperative development of nuclear energy by the AEC and private industry. In response, the AEC began a massive declassification of nuclear science data for the benefit of private users, and the Laboratory assumed a key role in the AEC's five-year plan to develop five new demonstration nuclear reactors. Launched in 1954, the AEC plan called for construction of a small pressurized-water reactor by Westinghouse Corporation; an experimental boiling-water reactor by Argonne National Laboratory; a fast breeder reactor, also by Argonne; a sodium-graphite reactor by North American Aviation; and an aqueous homogeneous-fuel reactor by Oak Ridge National Laboratory. Beyond its work on the homogeneous reactor, the Laboratory in the 1950s—as a national center for chemistry and chemical technology—focused on developing fluid fuels for nuclear reactors. The Laboratory concentrated on three possible options: fuels in solution, fuels suspended in liquid (or slurries), and molten salt fuels. Each one posed fundamental challenges in chemistry and chemical technology. Moving confidently from solids to liquids to gases in support of the AEC efforts on behalf of the atom, the Laboratory also conducted research for heterogeneous, solid-fuel reactors. It also provided conceptual designs for a transportable Army package reactor, a maritime reactor, and a gas-cooled reactor. The Cold War and President Eisenhower's "Atoms for Peace" speech reenergized and refocused the Laboratory's research efforts. In effect, it gave the Laboratory a multifaceted research agenda, many aspects of which were tied to the development and application of nuclear power. Summarizing the impact of the nation's postwar aims on the work of the Laboratory, Director Clarence Larson commented, "1954 has witnessed the transition that many of us have hoped for since the war. The increasing emphasis on peacetime applications of atomic energy," he went on to say, "has been a particular source of gratification." HOMOGENEOUS REACTOR In addition to the Aircraft Reactor Experiment, the Bulk Shielding Reactor, and the Tower Shielding Facility built as part of its Aircraft Nuclear Project for the Air Force, the Laboratory had three other major reactor designs in progress during the mid-1950s: its own new research reactor with a high neutron flux; a portable package reactor for the Army; and the Aqueous Homogeneous Reactor, which was unique because it combined fuel, moderator, and coolant in a single solution (designed as one of five demonstration reactors under AEC auspices). Initial studies of homogeneous reactors took place toward the close of World War II. It pained chemists to see precisely fabricated solid-fuel elements of heterogeneous reactors eventually dissolved in acids to remove fission products—the "ashes" of a nuclear reaction. Chemical engineers hoped to design liquid-fuel reactors that would dispense with the costly destruction and processing of solid fuel elements. The formation of gas bubbles in liquid fuels and the corrosive attack on materials, however, presented daunting design and materials challenges. With the help of experienced chemical engineers brought to the Laboratory after its acquisition of the Y-12 laboratories, the Laboratory proposed to address these design challenges. George Felbeck, Union Carbide manager, encouraged their efforts. Rather than await theoretical solutions, Laboratory staff attacked the problems empirically by building a small, cheap experimental homogeneous reactor model. Engineering and design studies began in the Reactor Experimental Engineering Division under Charles Winters, and in 1951 the effort formally became a project under John Swartout and Samuel Beall. This was the Laboratory's first cross-divisional program. Swartout provided program direction to groups assigned in the Chemistry, Chemical Technology, Metallurgy, and Engineering divisions, while Samuel Beall led construction and operations. Beecher Briggs headed reactor design; Ted Welton, Milton Edlund, and William Breazeale were in charge of reactor physics; Edward Bohlmann directed corrosion testing; and Richard Lyon and Irving Spiewak performed fluid flow studies and component development. A homogeneous (liquid-fuel) reactor had two major advantages over heterogeneous (solid-fuel and liquid-coolant) reactors. Its fuel solution would circulate continuously between the reactor core and a processing plant that would remove unwanted fissionable products. Thus, unlike a solid-fuel reactor, a homogeneous reactor would not have to be taken off-line periodically to discard spent fuel. Equally important, a homogeneous reactor's fuel and the solution in which it was dissolved served as the source of power generation. For this reason, a homogeneous reactor held the promise of simplifying nuclear reactor designs.
A building to house the Homogeneous Reactor Experiment was completed in March 1951. The first model to test the feasibility of this reactor used uranyl sulfate fuel. After leaks were plugged in the high-temperature piping system, the power test run began in October 1952, and the design power level of one megawatt (MW) was attained in February 1953. The reactor's high-pressure steam twirled a small turbine that generated 150 kilowatts (kW) of electricity, an accomplishment that earned its operators the honorary title "Oak Ridge Power Company." Marveling at the homogeneous reactor's smooth responsiveness to power demands, Weinberg found its initial operation thrilling. "Charley Winters at the steam throttle did everything, and during the course of the evening, we electroplated several medallions and blew a steam whistle with atomic steam," he exulted in a report to Wigner, asking him to bring von Neumann to see it. Despite his enthusiasm, Weinberg found AEC's staff decidedly bearish on homogeneous reactors and, in a letter to Wigner, he speculated that the "boiler bandwagon has developed so much pressure that everyone has climbed on it, pell mell." Weinberg surmised that the AEC was committed to development of solid-fuel reactors cooled with water and Laboratory demonstrations of other reactor types—regardless of their success—were not likely to alter its course. Despite AEC preferences, the Laboratory dismantled its Homogeneous Reactor Experiment in 1954 and obtained authority to build a large pilot plant with "a two-region" core tank. The aim was not only to produce economical electric power but also to irradiate a thorium slurry blanket surrounding the reactor, thereby producing fissionable uranium-233. If this pilot plant proved successful, the Laboratory hoped to accomplish two major goals: to build a full-scale homogeneous reactor as a thorium "breeder" and to supply cheap electric power to the K-25 plant to enrich uranium. Initial success stimulated international and private industrial interest in homogeneous reactors, and in 1955 Westinghouse Corporation asked the Laboratory to study the feasibility of building a full-scale homogeneous power breeder. British and Dutch scientists studied similar reactors, and the Los Alamos Scientific Laboratory built a high-temperature homogeneous reactor using uranyl phosphate fluid fuel. If the Laboratory's pilot plant operated successfully, staff at Oak Ridge thought that homogeneous reactors could become the most sought-after prototype in the intense worldwide competition to develop an efficient commercial reactor. Proponents of solid-fuel reactors, the option of choice for many in the AEC, would find themselves in the unenviable position of playing catch-up. But this was not to be. ARMY PACKAGE REACTOR Similar initial success flowed from studies at the Oak Ridge School of Reactor Technology, where a study group in 1952 proposed a compact, transportable package reactor to generate steam and electric power at military bases so remote that supplying them with bulky fossil fuels was too difficult and costly. The AEC and Army Corps of Engineers expressed a great deal of interest in this concept, and in early 1953 Laboratory management met with Colonel James Lampert and Army Corps of Engineers staff to initiate planning for such a mobile reactor. Alfred Boch and a team including Harold McCurdy and Frank Neill in the Electronuclear Division were given responsibility to design this small reactor. They selected a heterogeneous, pressurized-water, stainless steel system design that could use standard components wherever possible for easy replacement at remote bases. Walter Jordan led a Laboratory team that drew up specifications for a package reactor capable of generating 10 MW of heat and 2 MW of electricity. General Samuel Sturgis, chief of the Army Engineers, decided to build the reactor at Fort Belvoir, Virginia, where his officers could be trained to operate it.
The Army Package Reactor was the first reactor built under bid by private contractors. The Army Corps of Engineers, in fact, received 18 bids that ranged from $2.25 million to $7 million. The Corps awarded the contract to Alco Products (American Locomotive Company) in December 1954, and Alco completed the reactor in 1957. With a core easily transportable in a C-47 airplane, the Army Package Reactor could generate power for two years without refueling; a small oil-fired plant would consume 54,000 barrels of diesel fuel over the same period. The Army later built similar package reactors for power and heat generation in the Arctic and other remote bases. PURIFICATION Ancient athletes considered the Olympics a purifying experience. Purification was also a preoccupation of scientists who participated in the nuclear olympics of the 1950s--not personal purification, but fuel purification to enable nuclear reactors to operate more efficiently. Although designers of the homogeneous reactor hoped to achieve simultaneous reactor operation and fuel purification, other Laboratory technologists led successively by M. D. Peterson, Frank Steahly, and Floyd Culler sought to improve fuel purification by recovering valuable plutonium and uranium from spent fuel elements and separating them from fission products. Laboratory interest in these efforts was reflected by the subdivision of its Technical Division into the Reactor Technology and the Chemical Technology divisions in February 1950. The Reactor Technology Division carried out Laboratory responsibilities for reactor development, whereas the Chemical Technology Division, following the lead of the Laboratory's "separations and recovery" experience during and after World War II, sought to improve chemical separations processes.
The Laboratory's most important achievement during World War II had been the recovery of plutonium from Graphite Reactor fuel. Drawing on its wartime experience, the Laboratory attained notable success during the postwar years recovering uranium stored in waste tanks near the Graphite Reactor. Hanford's management called on Laboratory staff to address similar recovery problems at its plutonium production facilities in the state of Washington. The Laboratory also built a pilot plant to improve Argonne National Laboratory's REDOX process for recovering plutonium and uranium by solvent extraction. The pilot plant served as a prototype for an immense REDOX process plant completed at Hanford in 1952. To recover uranium from fuel plates at the AEC's Idaho reactor site, Frank Bruce, Don Ferguson, and associates improved the so-called "25 process," and Floyd Culler completed design of a large plant that used this process, also in 1952. Recovery, separation, and extraction—the primary components of fuel purification—were big business at the Laboratory during the 1950s. Such efforts played a major role in developing the Plutonium and Uranium Extraction (PUREX) process selected in 1950 for use at the Savannah River Plant reactors. Two huge PUREX plants were built at Savannah River in 1954 and a third at Hanford in 1956. Later, large plants using the PUREX process were built in other nations, and some Laboratory executives believe the PUREX process may constitute the Laboratory's greatest contribution to nuclear energy. By 1954, the Laboratory's chemical technologists had completed a pilot plant demonstrating the ability of the THOREX process to separate thorium, protactinium, and uranium-233 from fission products and from each other. This process could isolate uranium-233 for weapons development and also for use as fuel in the proposed thorium breeder reactors. During the 1950s, the Laboratory's Chemical Technology Division served as the AEC's center for pilot plant development, echoing the Laboratory's wartime role in plutonium recovery and extraction. The succession of challenges it had to meet—uranium-235 recovery, PUREX development, and construction and operation of the REDOX and THOREX pilot plants—swelled the ranks of the Chemical Technology Division from fewer than 100 people in 1950 to almost 200 in 1955. A similar expansion took place in the Analytical Chemistry Division. Its staff increased from 110 people to 214 people during the same period. The fuel purification program brought Eugene Wigner back to the Laboratory in 1954. Wigner had been working for Du Pont on the design of the Savannah River reactors when he agreed to return to Oak Ridge to apply his chemical engineering expertise to design a solvent extraction plant. Labeled Project Hope because it promised to extend the supply of fissionable materials for energy production, Wigner's 1954 study resulted in the design of a processing plant able to recover uranium-235 from spent fuel for reuse in reactors at a cost of $1 per gram, much lower than the prevailing cost of $7.50 per gram of uranium from ore. His study helped turn the attention of the Laboratory's chemical technologists from improving individual processes for recovery of uranium, plutonium, and thorium to developing an integrated plant capable of separating all nuclear materials at a single site. The proposed power reactor fuel reprocessing facility would have competed with private industry, however, and eventually the AEC decided not to construct it. OAK RIDGE RESEARCH REACTOR In 1953, the Laboratory received AEC approval to build a new research reactor. The reactor design, blueprinted by Tom Cole's team, combined features of the Materials Testing Reactor and the Bulk Shielding Reactor. With a thermal power rating of 20 MW, its neutron flux—the neutron beam intensity so critical for research—was 100 times greater than that of the Graphite Reactor and was exceeded only by that of the Materials Testing Reactor in IdaTesting Reactor and the Bulk Shielding Reactor. With a thermal power rating of 20 MW, its neutron flux—the neutron beam intensity so critical for research—was 100 times greater than that of the Graphite Reactor and was exceeded only by that of the Materials Testing Reactor in Idaho.supporting many scientific advances. Physicists Cleland Johnson, Frances Pleasonton, and Arthur Snell performed the first scientific experiments at the Oak Ridge Research Reactor. Examining the relative directions of neutron and electron (beta particle) emissions in the decay of helium-6 nuclei, they confirmed the electron- neutrino theory of nuclear beta decay. The results guided the improvement of the recoil spectrometry techniques pioneered by Snell and his colleagues. Information on the masses, energies, and nuclear particles of fission fragments was obtained at the ORR by John Dabbs, Louis Roberts, George Parker, John Walter, and Hal Schmitt. Jack Harvey, Bob Block, and Grimes Slaughter used time-of flight spectrometry to obtain data for the design of fission power reactors.
Neutron scattering research at the ORR by Wallace Koehler, Mike Wilkinson, Ralph Moon, Joe Cable, and Ray Child examined the magnetic properties of rare earths and other materials. Using a triple-axis spectrometer at an ORR beam port, Harold Smith, Wilkinson, Bob Nicklow, and Herb Mook gained new insights on the dynamic properties of solids and the interatomic forces in various crystals. Henri Levy, Selmer Peterson, Smith, Bill Busing, and George Brown pioneered automated single-crystal neutron diffraction studies, producing information on the structure of such materials as sugar crystals. A Physics Division team composed of Philip Miller, James Baird, and William Dress worked at the ORR in collaboration with Norman Ramsey of Harvard for a decade, conducting a series of experiments on an electrical charge characteristic of neutrons. They designed and operated a novel neutron spectrometer based on Ramsey's separated oscillatory-field method for magnetic resonance. For this work and other investigations of the fundamental characteristics of the proton and neutron, Ramsey was awarded the Nobel Prize in physics in 1989. Another example of pioneering research at the ORR was completed from 1974 to 1978 by Kirk Dickens, Bob Peelle, Temple Love, and Jim McConnell of the Neutron Physics Division together with Juel Emory and Joe Northcutt of the Analytical Chemistry Division. They measured the rate of heat generation from the decay of fission products in reactor fuel, an effect crucial to determining what might happen during loss-of coolant accidents at reactors and how much emergency cooling would be required for reactor cores. Using sets of capsules moved mechanically into and out of the ORR's neutron stream, nuclear fuels for reactors were tested. These capsules often had colorful names, such as the "eight-ball capsule" used to test spherical fuel for a German gas-cooled reactor. For gas-cooled reactor experiments led by John Conlin, John Coobs, and Edward Storto, two fuel irradiation test loops using circulating helium were installed at the ORR. To qualify a second reactor core for the nuclear ship Savannah, I. T. Dudley installed a pressurized-water loop at the ORR. Donald Trauger, who had charge of the tests using capsules and loops, notes that the testing facilities were later copied for similar testing of reactors in the Netherlands and elsewhere. Clifford Savage built and operated an engineering-scale test loop at the ORR to study fuel behavior and corrosion rates for the Laboratory's Homogeneous Reactor Experiment. Although not the first of their type, these engineering-scale experiments were the most advanced of their time. During the last experiments at the ORR before its operation ceased in 1987, its highly-enriched uranium fuel was replaced with low-enriched fuel containing only 20 percent uranium-235. The last experiments revealed that low-enrichment fuel could be substituted for highly enriched fuel in most research reactors. Such a switch could allay fears that highly enriched fuel might be diverted into nuclear weapons production. The research reactor's presence caused scientists and engineers from throughout the world to seek assignments at the Laboratory. For the less scientifically inclined, the reactor became a tourist attraction. An impressive structure, silhouetted by the blue glow of Cerenkov radiation emanating from the core within its protective pool, the Oak Ridge Research Reactor was admired in person by Senator John Kennedy, U.S. Representative Gerald Ford, and other noted and aspiring political figures. Thanks to relaxed security requirements in the wake of President Eisenhower's call for international cooperation, the reactor also lured many foreign scientists and dignitaries, such as the queen of Greece and the king of Jordan, who came to the Laboratory on other business but could not pass up an opportunity to see one of the facility's most notable pieces of equipment. (See related article, VIPs at the ORR.) 1955 GENEVA CONFERENCE
The Laboratory's new research reactor was being designed at the same time that plans were being made for the first United Nations Conference on Peaceful Uses of Atomic Energy. That conference was scheduled for Geneva, Switzerland, in August 1955. A staid, professional scientific meeting, organized in response to Eisenhower's "Atoms for Peace" initiative, it also became an extravagant science fair with exhibits from many nations emphasizing their scientific achievements. (See related article, 1955 Geneva Conference.) Never before had the accomplishments of nuclear power been placed on such a public stage. And never before had scientists so openly presented their findings as symbols of national prestige. Just as the athletic Olympics in the post-World War II era emerged as peaceful arenas for venting Cold War animosities, the 1955 Geneva conference on the atom became a platform for comparing the relative strengths of science in capitalist and communist societies. Because critical assessments of the exhibits, especially those brought by the Soviets and Americans, were expected, the AEC asked its laboratories for spectacular exhibit concepts. At Oak Ridge, Tom Cole's suggestion that the AEC build and display a small nuclear reactor was welcomed.
In early 1955, a Laboratory team led by Charles Winters and William Morgan designed and fabricated a scaled-down version of the Materials Testing Reactor, operating at 100 kW instead of 30 MW. The Laboratory designed it as the first reactor to use low-enriched uranium dioxide fuel. When the fuel plates were fabricated, however, a reaction between the uranium dioxide and aluminum caused the plates to distort. Jack Cunningham's team finished resetting the plates just before shipment. After testing, the reactor was disassembled and sent by air from Knoxville to Geneva, where the Laboratory team reassembled it in a building constructed on the grounds of the Palais des Nations. Designed, built, tested, transported to Geneva, and reassembled in only five months, it became the most spectacular display at the conference, admired by political dignitaries such as President Eisenhower as well as by the public and media. The reactor and the 28 scientific papers presented to the conference by staff members gave the Laboratory a claim to the laurels of the international competition. Heralding the multifaceted applications of peaceful atomic power, the Geneva conference captured the public's imagination. After the conference, the U.S. exhibit returned home for a triumphant national tour, minus its most eye-catching element. The Swiss government had purchased Oak Ridge's model Materials Testing Reactor to use at a research facility.
At the same time, the Laboratory acquired its own version of the Geneva reactor. To ensure against loss of the reactor during shipment to Switzerland, Charles Winters had made duplicates of all its components. These were assembled in the pool of the Laboratory's Bulk Shielding Reactor and became known as the Pool Critical Assembly. John Swartout later recalled the chiding he received from AEC management for allowing the Pool Critical Assembly to be built without advance AEC approval. Swartout pointed out that if the reactor were safe enough to be operated within the city of Geneva, it certainly was safe within the confines of the Laboratory. "Our Laboratory stands today as an institution of international reputation," exulted Alvin Weinberg, who became Laboratory director shortly after the conference. "This we sense from our many distinguished foreign visitors, from the numerous invitations which our staff receives to foreign meetings, and in the substantial part which we played at Geneva. But with international reputation comes international competition." And, as any Olympic champion will tell you, as difficult as it is to win the first gold medal, it is even more difficult to sustain a level of performance unequalled by others. GAS-COOLED REACTOR International exchange on nuclear matters brought the Laboratory a new assignment from the AEC: to explore gas-cooled nuclear reactor technology. Although U.S. studies of gas-cooled reactors waned after investigations into the Daniels Power Pile were halted in 1948, British scientists successfully designed and built several large gas-cooled reactors in the early 1950s. In 1956, Congress reacted to the British advances by directing the AEC to gain first-hand experience with gas-cooled, graphite-moderated reactors. In response, AEC turned to the Laboratory, which formed a study team headed by Robert Charpie. The team's key task was to compare the feasibility and costs of gas-cooled and water-cooled reactors. Encouraged by the initial findings, in 1957, the AEC asked the Laboratory to design fuel elements for the Experimental Gas-Cooled Reactor (EGCR), which the AEC planned to build in Oak Ridge. By early 1958, the Laboratory had completed a conceptual design for a helium-cooled, graphite-moderated reactor. Its core was to consist of uranium oxide clad in stainless steel. A team led by Murray Rosenthal also studied fuel elements coated with graphite as an alternative. John Conlin, Frank McQuilkin, and Don Trauger led a team that assessed these competing concepts.
In 1959, after the Tennessee Valley Authority agreed to become the reactor operator, the AEC arranged for the EGCR to be constructed on the banks of the Clinch River near the Laboratory. The reactor was to serve as a prototype for electric power generation and TVA—the nation's largest public utility—hoped to participate in a demonstration that held great promise for helping the agency meet its customers' future power needs. In line with its previous research, ORNL was given responsibility for developing and fabricating the EGCR's fuel elements and moderator. Eight test loops inside the reactor would have allowed Laboratory scientists to test the various fuel elements. Construction delays and increasing project costs, however, soon caused the test loops to be eliminated from the design. Then, in 1966, the AEC ordered the project stopped even though all construction on the reactor had been completed and its fuel elements had been manufactured and fully tested. The light-water reactor industry had advanced so rapidly that the Oak Ridge gas-cooled reactor prototype had become obsolete before it had become operational. MOLTEN SALT TECHNOLOGY
Another innovative nuclear reactor design was developed at the Laboratory in 1956 when a team headed by Herbert MacPherson investigated the application of molten salt technology. The Laboratory's aircraft reactor experiments during the early 1950s used molten (fused) uranium fluorides (salts) as reactor fuel. Molten-salt fuel could function at high temperatures and low pressures in a liquid system that could be cleansed of fission products without stopping the reactor. Like other liquid nuclear fuels, however, molten salts were highly corrosive and posed significant materials challenges. To meet these challenges, MacPherson organized a group that studied molten materials in the test loops built for the aircraft reactor project and assigned to Alfred Perry the cost studies for various molten-salt reactors. Teams headed by Beecher Briggs, Paul Kasten, L. E. McNeese, and William Manly developed improved designs and focused on identifying corrosion-resistant materials for use in molten-salt reactors.
When an AEC task force in 1959 identified molten salt as the most promising of the liquid-fuel reactor systems, the AEC approved construction of the Molten Salt Reactor Experiment. By 1960, the Laboratory was designing an experimental molten-salt reactor using graphite blocks as the moderator. A uranium-bearing fuel of molten fluorides was pumped through the core and through a heat exchanger made of a nickel-molybdenum alloy, called Hastelloy N, developed earlier at the Laboratory for the aircraft reactor. Ed Bettis headed a design team that continually refined the reactor configuration. Warren Grimes provided chemical insights that determined many features of the system.
Molten-salt reactor experiments continued at the Laboratory through the 1960s and into the early 1970s. In 1969, Keith Brown, David Crouse, Carlos Bamberger, and colleagues adapted molten-salt technology to the problem of breeding uranium-233 from thorium, which could be extracted from the virtually inexhaustible supply of granite rocks found throughout the earth's crust. When bombarded by neutrons in the molten-salt reactor, thorium was converted to fissionable uranium-233, another nuclear fuel. PROJECT SHERWOOD Alvin Weinberg described the Laboratory's use of the uranium-233 reactor fuel bred from neutron irradiation of thorium as "burning the rocks"; conversely, he called its secret investigations of producing fusion energy from heavy water (deuterium oxide), which could be obtained from sea water, "burning the sea." Thus, by the late 1950s Laboratory researchers were searching for an inexhaustible energy supply extracted either from the earth's crust or seas. Using elements found in abundance in granite or seawater would potentially provide limitless energy.om the earth's crust or seas. Using elements found in abundance in granite or seawater would potentially provide limitless energy.
The Laboratory's fusion research efforts were no less Promethean than its fission research. Such research began in Oak Ridge in 1953 as a small part of the AEC's classified Project Sherwood. By the time of the second scientific olympics at Geneva in 1958, however, the Laboratory had become a world leader in fusion research. Hydrogen nuclei release enormous energy when they fuse together, as in the thermonuclear reaction associated with detonation of a hydrogen bomb. Fusion temperatures of the hydrogen isotopes deuterium and tritium are about one million degrees. Major research aimed at fusing these isotopes in a controlled thermonuclear reaction began in 1951, when Argentine President Juan Peron announced that scientists in his country had liberated energy through thermonuclear fusion without using uranium and under controlled conditions that could be replicated without causing a holocaust.
Peron's claim proved false, but it stimulated a host of international fusion research initiatives, including the AEC's classified Project Sherwood. Legend has it that the name Sherwood came from the answer to the question, "Would you like to have cheap, nonpolluting, and everlasting energy?" The answer was "Sure would." In reality, the name was derived from a complicated pun on the story of Robin Hood of Sherwood Forest, which involved robbing Hood Laboratory at the Massachusetts Institute of Technology to fund James Tuck's fusion research at Los Alamos. To achieve fusion, scientists sought to contain a cloud, or plasma, of hydrogen ions at high temperature in a magnetic field. Because the plasma cooled if it touched the sides of its container, electromagnetic forces (pushing from different directions) were necessary to hold the plasma in the center away from the container's sides. If the plasma were suspended in the same place long enough and at a high enough density and temperature, scientists believed a fusion reaction would begin and become self-sustaining.
In its early years, Project Sherwood focused on three fusion devices. Princeton University had a stellarator, a hollow twisted doughnut-shaped metal container, with electric wires coiled around it to supply a magnetic field to confine the charged hydrogen ions. Lawrence Livermore Laboratory in California had a "mirror" device with a magnetic field stronger at its ends than in the middle to reflect hydrogen ions back to the middle of the field. And James Tuck's "Perhapsatron" at Los Alamos sought to contain the hot plasma through a "magnetic pinch"--that is, magnetic forces were designed to hold, or pinch, the plasma toward the middle of the container. In Oak Ridge, the Laboratory focused not on a particular device but on two problems basic to fusion devices: how to inject particles into the devices and how to heat the plasma to temperatures high enough to ignite the reaction. With large surplus electromagnets on hand at the Y-12 Plant from the calutrons once used to separate uranium-235 from uranium-238, an ion source group in the Electronuclear Division, which included Ed Shipley, P. R. Bell, Al Simon, and John Luce, became responsible for fusion research. Their background in electromagnetic separation and high-current cyclotrons led them to studies of energetic ion injection to create a hot plasma. Theoretical work showed promise and, in 1957, the Laboratory formed a Thermonuclear Experimental Division with a staff of 70 people to pursue the fusion challenge. Personnel came from the Physics and Electronuclear divisions and from the discontinued aircraft reactor project. In 1957, published stories and unsubstantiated rumors hinted that British scientists might have achieved a successful fusion reaction. Although overstated, the stories and rumors nevertheless encouraged greater emphasis on fusion research by both the AEC and the Laboratory. Moving a particle accelerator into the Y-12 Plant to provide a beam of high-energy deuterium molecular ions, Luce, Shipley, and their associates built the Direct Current Experiment (DCX), a magnetic mirror fusion device. In August 1957, they "crossed the swords," injecting a deuterium molecular beam into a carbon arc that dissociated the beam into a visible ring of circulating deuterium ions (shaped like a bicycle tire). This advance transformed Project Sherwood from a remote, abstract theory to a real possibility. (See related article, Crossing the Swords.) Planning for a second United Nations Conference on Peaceful Uses of Atomic Energy coincided with the Laboratory's advance in fusion research. AEC Chairman Lewis Strauss, determined that the United States should achieve a triumph equal to that of 1955 at the 1958 scientific olympics, threw the AEC's full support behind fusion research. He hoped that American scientists could display an operating fusion energy device at the 1958 Geneva conference, just as they had displayed a successful nuclear reactor three years earlier.
"I have received a letter from Chairman Strauss exhorting the Laboratory to do everything it possibly can to have incontrovertible proof of a thermonuclear plasma by the time of Geneva," Weinberg informed Laboratory staff. He went on to say:
1958 GENEVA CONFERENCE By the time of the second United Nations Conference on Peaceful Uses of Atomic Energy in September 1958, intense media attention on the miracles of nuclear energy had jaded the public. Saturated for years with news about the potential miracles of nuclear energy, Americans turned their attention to other matters. Moreover, Soviet scientists, so prominent at the 1955 conference, were no longer subjects of great public curiosity. As a result of this diminishing public interest, the second Geneva conference turned out to be less a media circus and more a conventional scientific conference. In 1958, only schemes and devices for achieving controlled thermonuclear reaction through fusion enjoyed the glamour linked to the first conference. The second conference, however, was the largest international scientific conference ever held. Exhibits filled a huge hall built on the grounds of the Palais des Nations. Sixty-one nations participated, and 21 exhibited fusion devices, fission reactors, atom smashers, or models of nuclear power plants. The United States, Great Britain, and the Soviet Union declassified their fusion research at the time of the conference, and Chairman Lewis Strauss resigned from the AEC to lead the American delegation to Geneva. It took nearly 10 hours to view the United States exhibit alone. The most popular attractions were models of the Laboratory's DCX fusion machine. The Laboratory provided two full-scale working models of its DCX machine to display its operating principles. Through viewing windows, visitors could see the beam, and the ring of ions wound around it like a ball of yarn. Using a bit of showmanship, the Laboratory made the trapped ring visible by dusting it with tungsten particles from above. Soviet fusion specialists took intense interest in the DCX display because they were also pursuing a molecular-ion-injection approach to fusion. After the conference, other nations, drawing on the Laboratory's experience, built DCX-type machines, making them fundamental tools for plasma research. Optimism over the future success of fusion energy, however, soon faded. The supposed British achievement of fusion with a pinch-type device proved premature, and the ability of pinch machines to provide a stable plasma was questioned. Unstable plasma escaping the magnetic field also plagued the Princeton stellarator, and by the end of 1958, Laboratory scientists learned that their carbon arc lost trapped ions, forcing the DCX staff to study different types of arcs and to plan an improved device, called DCX-2. In 1959 Alvin Weinberg, a proponent of nuclear fission and thorium breeding reactors, compared Project Sherwood to "walking on planks over quicksand." Plasma physics was so novel then that solid spots remained unknown, nor was it fully apparent that any existed. "Working in this field requires a rugged constitution," Weinberg concluded, "but I'm told that those who can stand it find it stimulating." Eugene Wigner reported that Soviet scientists were more cooperative at the 1958 Geneva conference than they had been in 1955, perhaps because of the successful launch of the Sputnik satellite into orbit in 1957. Wigner found them open about their nuclear fission and fusion energy research but unwilling to share information about their space missions or their particle acceleration program. "Pure science in the Soviet Union still seems to be far from an open book," he observed. Early Soviet achievements in space exploration sent shock waves throughout American political and scientific circles. Following the Soviet Union's successful launch of Sputnik, international scientific competition shifted from fission and fusion energy research to the race for space. As international scientific interests shifted, so did the focus of the federal government from the AEC to the new National Aeronautics and Space Administration (NASA). Nuclear research remained an important aspect of America's scientific agenda, but it now had to share the policy spotlight with space issues. Geneva conferences on the atom were held occasionally after 1958, but none ever gripped the public imagination as had the first and second stellar events. AFTER THE GOLD Nuclear reactor development at the Laboratory reached a pinnacle in 1956 and began a slow descent in 1957 with the cancellation of its aircraft reactor program and troubles with its second experimental homogeneous reactor. In 1956, when the Laboratory budget was $60 million and its staff reached 4369, Weinberg boasted: "We are the largest nuclear energy laboratory in the United States, and we are among the half-dozen largest technical institutions in the world." With cancellation of the aircraft reactor in September 1957, the Laboratory budget was slashed 20% and its staffing cut to 3943. The 1957 reduction would have been even steeper if the Laboratory had not absorbed some people into the molten-salt reactor, gas-cooled reactor, and Sherwood programs. Moreover, the Eisenhower administration froze the Laboratory's budget in 1957, forcing postponement of a major building expansion program that included an east wing of the general research building, an instruments building, and a metallurgy and ceramics building, which together would have added a half million square feet of work space. Weinberg called these actions "cataclysmic setbacks" that ranked with the loss of the Materials Testing Reactor in 1947. HOMOGENEOUS REACTOR After successful operation of the first aqueous homogeneous reactor in 1954, the Laboratory proceeded with design of a larger homogeneous reactor on a pilot-plant scale. Whereas the first reactor had been a one-time experiment to prove yet unproven theoretical principles, the second reactor, sometimes identified as the Homogeneous Reactor Test, was designed to operate routinely for lengthy periods.
The second homogeneous reactor was fueled by a uranyl sulfate solution containing 10 grams of enriched uranium per kilogram of heavy water, which circulated through its core at the rate of 400 gallons (1450 liters) per minute. Its fuel loop included the central core, a pressurizer, separator, steam generator, circulating pump, and inter-connected piping. Its core vessel was approximately a meter in diameter and centered inside a 60-inch (152-centimeter) spherical pressure vessel made of stainless steel. A reflector blanket of heavy water filled the space between the two vessels. Perhaps the most exotic nuclear reactor ever built, it gave Laboratory staffers trouble from the start. During its shakedown run with pressurized water, chloride ions contaminated the leak-detector lines, forcing replacement of that system and delaying the power test six months. In January 1958, the Laboratory brought this reactor to critical mass and operated it for many hours into February 1958, when it became apparent that its outside stainless steel tank was corroding too rapidly. In April the reactor reached its design power of 5 MW. Then, in September, a hole suddenly formed in the interior zircaloy tank. Viewing the hole through a jury-rigged periscope and mirrors, operators determined that it had been melted into the tank--that is, the uranium had settled out of the fuel solution and lodged on the tank's side. By the end of 1958, the AEC considered abandoning the Homogeneous Reactor Test, and Eugene Wigner came to the Laboratory to inspect it personally. "The trouble seems to be that the rich phase adsorbs to the walls and forms a solid layer there," Wigner reported to the AEC staff, relaying the findings of the Laboratory staff. He thought altering the flow of fluid through the core would provide the velocity needed to prevent the uranium from settling on the tank walls. "It is my opinion that abandoning the program would be a monumental mistake," he warned, pointing out that the reactor could convert thorium into uranium-233 to supplement a dwindling supply of uranium-235. The AEC allowed the Laboratory to alter the reactor flow and continue its testing in 1959. These activities were accomplished by interchanging the inlet and outlet to reverse the fluid flow through the reactor. Several lengthy test runs followed in 1959, and the reactor operated continuously for 105 days—at the time, a record for uninterrupted operation of reactors. The lengthy test run demonstrated the advantages of a homogeneous system in which new fuel could be added and fission products removed during reactor operation.
Near the end of the year, a second hole burned in the core tank. Laboratory staff again patched the hole using some difficult remote repairs and started another test run. Because of these difficulties, Pennsylvania Power and Light Company and Westinghouse Corporation abandoned their proposal to build a homogeneous reactor as a central power station. During the shutdown and repairs, Congress viewed the aqueous homogeneous reactor troubles unfavorably, and in December 1960, the AEC directed the Laboratory to end testing and turn its attention to developing a molten-salt reactor and thorium breeder. The last aqueous homogeneous reactor test run continued until early 1961. For months, the reactor operated at full power until a plug installed earlier to patch one of the uranium holes disintegrated. Although the homogeneous reactor never found direct commercial applications, the Laboratory's efforts to test its long-term usefulness ultimately strengthened its capabilities for maintaining and repairing highly radioactive systems. MATERIAL CHALLENGES The rapid pace of reactor development at the Laboratory prompted research in detecting flaws in reactor materials that could be signs of impending failure. In short, Laboratory staff investigated not only how reactors would run, but whether materials in reactor components could withstand the stresses of radiation over the long term. In 1955, for example, R.B. Oliver was given responsibility for developing and applying new techniques to detect welding flaws. Nuclear reactors, on a commercial scale, would contain miles and miles of piping and machinery seamed together by an endless series of welds, which would prove critical to a reactor's operation and safety. Moreover, the materials used for the pumps, piping, and containment of a nuclear reactor all would be subject to long-term, sometimes intense, radiation. "Material" concerns had been a major focus of the nuclear airplane program and it remained a key research initiative throughout the Laboratory's reactor development era between the 1950s and 1970s. In fact, by developing and demonstrating non-obstrusive techniques to test the integrity of materials (for example, ultrasonic waves and penetrating-radiation), the Laboratory became a world leader in "nondestructive" materials testing. Robert McClung headed this Laboratory program from the 1960s to the 1980s. Health physicists continued to seek a better understanding of how radiation from reactors and other sources interacts with solids and liquids. In the early 1950s ORNL scientists measured energy losses of swift electrons after penetrating thin metal foils. Rufus Ritchie launched the quantitative understanding of electron energy losses in irradiated solids and liquids by discovering the surface plasmon, a motion of electrons in matter. In this motion, electrons move collectively in response to the electric field of a penetrating charged particle. This surface motion remains a major topic of research because it helps explain surface phenomena. Only now are the potential applications of this knowledge being realized in computing, communications, laser technology, environmental monitoring, and medical diagnosis and treatment. ECOLOGICAL CHALLENGES Even as the Laboratory moved forward with its nuclear energy program, unmet challenges relating to nuclear fission and the Laboratory's missions arose—most notably, the threat of radioactive fallout from atmospheric testing of nuclear bombs and the need to deal more effectively with radioactive wastes called for research by the Laboratory's scientists. The need to broaden the Laboratory's base and avoid competition with private industry also challenged its management.
Until 1963, fission and fusion bomb tests were conducted in the atmosphere, causing much public concern about radioactive fallout. A principal concern during the early 1950s was the fallout of strontium-90, a calcium-mimicking, bone-seeking fission product that fell from windblown clouds to the soil below, where it could be taken up by grass and eaten by cows to wind up in milk consumed by humans. To study this and other issues of radiation ecology, the Laboratory, responding to the recommendation of Edward Struxness, hired Orlando Park, an ecologist from Northwestern University, as a consultant in 1953. The Laboratory subsequently asked Park's student, Stanley Auerbach, to join its Health Physics Division. Both Park and Auerbach were expert investigators of the effects of radioactivity on ecological systems, particularly how radioactive nuclides migrate from water and soil to plants, animals, and humans. A major issue in the early 1950s was how quickly strontium-90 in the soil was taken up by plants. In fact, this and other questions about radioactive fallout became issues in the 1956 presidential election. During the same year, the Laboratory expanded its scientific studies of radioactive fallout into a Radiation Ecology Section in the Health Physics Division, and Auerbach was named section leader. Auerbach and his colleagues found a ready field laboratory for their work in the bed of White Oak Lake, a drained reservoir where the Laboratory once had flushed low-level wastes. Examining the native plants and even planting corn in the radioactive lake bed, the ecologists studied the manner in which vegetation absorbed radionuclides from the environment. Investigations of insects, fish, mammals, and other creatures followed, enabling Laboratory ecologists to establish international reputations in aquatic and terrestrial radioecology. Taking advantage of the Laboratory's isotopes, the ecologists used radioactive tracers to follow the movements of animals, the route of chemicals through the food chain, and the rates of decomposition in forest detritus. Sponsoring national symposia on ecosystems and related subjects, their work added much to the study of radioecology, an emerging scientific field that counts Auerbach and his colleagues among its founders. When atmospheric bomb testing ended in 1963 and interest in fallout waned, the ecologists refocused their studies, forming the nucleus of the Ecological Sciences Division, established at the Laboratory in 1970 and later renamed the Environmental Sciences Division. During World War II, the Laboratory stored its radioactive wastes in underground tanks for later recovery of the uranium and released its low-level wastes untreated into White Oak Lake. To reduce the level of radioactivity entering White Oak Creek and eventually the Clinch River, the Laboratory built a waste treatment plant during the 1950s to remove strontium and other fission products from its drainage. Uranium and other materials were recovered from underground tanks, and the remaining wastes were pumped into disposal pits.
In 1953, the Laboratory initiated a multipronged remediation program designed to address its higher-level waste disposal problems. The Chemical Technology Division devised a pot calcination strategy that heated high-level liquid wastes in steel pots, converting the wastes into ceramic material for easier handling and storage. The Health Physics Division, under the direction of Edward Struxness and Wallace de Laguna, explored the hydrofracture disposal method used by the petroleum industry. The strategy consisted of drilling deep wells, applying pressure to fracture the rock substrata, and pumping cement grout mixed with radioactive wastes down the wells into the rock cracks, where the mixture spread out and hardened. Struxness and Frank Parker of the Health Physics Division initiated studies of waste disposal in salt mines, which were believed to be isolated from water. In 1959 the Laboratory tested this method by storing electrically heated, nonradioactive wastes in a Kansas salt mine. Under pressure from the state of Kansas, the AEC asked the Laboratory to stop the Kansas studies after wells were found near the salt mines. This and other methods that seemed promising during the 1950s presented difficulties, and none permanently resolved the disposal challenges. (See related article, Ellison Taylor: Player-Coach of Chemistry.) As the Laboratory's operating nuclear reactors increased in number and its fuel processing program burgeoned, the safety of equipment and the health of its personnel became a growing concern. Such concerns came to the forefront after a serious nuclear mishap in England during the late 1950s. At Windscale, England, a British graphite-moderated reactor caught fire in 1957 when its operators attempted to anneal it to release the energy stored in the graphite as a result of the "Wigner disease." (Annealing is a process of heating and slow cooling to increase a material's toughness and reduce its brittleness.) Herbert MacPherson and a Laboratory team visited Windscale to review the accident and consider its implications for operation of the Laboratory's Graphite Reactor. MacPherson reported that the Laboratory's reactor operated at lower power and higher temperature than the Windscale reactor and that a similar accident could not occur in Oak Ridge. In the early 1960s, the Graphite Reactor was annealed three times without difficulties by reversing and reducing its air flow and slowly raising power.
Although ORNL had experienced no reactor accidents, in 1959 it encountered three threatening situations involving radioactive materials. First, fission products accidentally entered the liquid waste disposal system from the THOREX pilot plant, and they were trapped in a settling basin. Second, ruthenium oxide trapped on the brick smokestack's rusty ductwork shook loose during maintenance at the pilot plant, forcing installation of more filters and scrubbers in the stack. And, third, a chemical explosion in the THOREX pilot plant during decontamination released about six-tenths of a gram of plutonium from a hot cell, spreading it onto a street and into the Graphite Reactor building next to the plant. Largely by chance no personnel suffered overexposure from these accidents, and the Laboratory immediately stopped its radiochemical operations for safety review. Improved containment measures followed, and Frank Bruce took charge of the Laboratory's radiation safety and control office to implement stricter safety precautions. P. R. Bell and Casimir Borkowski also devised ingenious compact radiation monitors, including the "pocket screamer," which was worn in the pocket and chirped and flashed at a speed proportional to gamma dosage rate. These devices were supplied as needed to Laboratory personnel who worked with reactors and hot cells.
In addition to these challenges, the Laboratory found it increasingly difficult to keep background radiation at acceptable levels because the amount of radioactivity handled by the Laboratory increased during the 1950s, while government regulators steadily reduced the permissible levels to which workers could be exposed. Karl Morgan and other Laboratory health physicists maintained that the maximum permissible levels should be so low that hazards resulting from radiation were no greater than other occupational hazards. Laboratory biologists, however, had obtained differing results in studies of the effects of background radiation. Arthur Upton, for example, found that mice subjected to chronic low-level radiation seemed to have an improved survival rate from infections or other biological crises. In 1955 ORNL's Health Physics Division became involved in helping to determine the health effects of various levels and types of radiation from the atomic bomb. With researchers from Los Alamos Scientific Laboratory, ORNL health physicists conducted the first major field experiment to measure levels of neutron and gamma radiation at various distances from the hypocenter of bomb blasts at the Nevada Test Site. In 1956 health physicists Sam Hurst and Rufus Ritchie made the first of a series of Laboratory visits to Japan to correlate the Laboratory's information from the Nevada tests with data developed by Japan's Atomic Bomb Casualty Commission. Laboratory researchers evaluated the shielding capabilities of Japanese houses and other structures and recommended a dosimetry program to determine whether the survivors were properly shielded from radioactive materials in the environment.
COMPETITIVE CHALLENGES The Laboratory faced not only international competition during the late 1950s but also increasing competition at home from private nuclear companies. By 1959, the rapidly growing nuclear industry questioned the role of national laboratories, urging that some of their work be contracted to private industry or even that the laboratories be closed. Partly as a result of these pressures, the AEC circumscribed Laboratory programs in the late 1950s. For example, the AEC canceled the power reactor fuel reprocessing facility that the Chemical Technology Division hoped to build in Oak Ridge. In 1959, the Laboratory also recognized that it could soon lose its homogeneous and gas-cooled reactor programs. In response to the expected decline in its nuclear reactor and chemical reprocessing programs, the Laboratory conducted an advanced technologies seminar in 1959 to identify possible missions beyond nuclear energy. The seminar recommended additional study of nationally valuable research programs that had not been commercially exploited. Desalination of sea water, meterology, oceanography, space technology, chemical contamination, and large-scale biology were mentioned as potential broad avenues of inquiry. Although convinced that federal investment in national laboratories was too great to permit their abandonment, Weinberg recognized that a realignment of their missions was in order. Asked to forecast the role of science and national laboratories during the 1960s, Weinberg expressed his hope that they "will be able to move more strongly toward those issues, primarily in the biological sciences, which bear directly upon the welfare of mankind." The Olympics of antiquity had begun as a single event: a long distance race between the best runners of competing Greek city-states. The modern Olympics, particularly in the post-World War II era, have been transformed into a sports carnival where athletes display their diverse skills as runners, swimmers, equestrians, weight lifters, skeet shooters, and volleyball and basketball players.
In the same way, the scientific olympics in which the Laboratory competed began as a contest comparing the scientific prowess of the Soviet Union and the United States. The Laboratory, as one of America's primary institutions for scientific research, had a simple goal: display the nation's scientific talent and accomplishments in the most dramatic way possible. As the 1950s unfolded, however, the contest became more diverse and complicated. Space issues eclipsed the importance of nuclear research as the most important symbol of a nation's scientific capabilities; other goals began to compete for the Laboratory's resources and energies; and the initial successes of fission and fusion research proved difficult to replicate. In short, like Olympic runners who followed in the path of their earliest brethren, Laboratory scientists by the end of the 1950s found they would have to share the arena with other figures and other events. As the Laboratory entered the 1960s, its work would be less dramatic but no less important, and its focus more diverse but no less compelling. Related Web sites ORNL
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