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Chapter 2: High-Flux Years

High-flux conditions prevailed at Clinton Laboratories after the war, when surprising decisions affecting the facility's future were made in St. Louis, Chicago, and Washington, D.C. At the federal level, management of the national laboratories shifted from General Leslie Groves and the Army Corps of Engineers to David Lilienthal and the newly created civilian Atomic Energy Commission (AEC). In Oak Ridge, the contract with Monsanto Chemical Company, the industrial operator for Clinton Laboratories, was not renewed. The University of Chicago, the proposed academic operator, failed to assemble a management team, resulting in the selection of a new industrial contractor, Union Carbide Corporation. Clinton Laboratories became Clinton National Laboratory in 1947 and Oak Ridge National Laboratory in 1948. Change was the watchword in the tumultuous postwar period, as one unexpected event followed another.

General Leslie Groves and David Lilienthal discuss the transfer of responsibility for
atomic energy research and development and weapons production from the
Army to the civilian Atomic Energy Commission.
General Leslie Groves and David Lilienthal discuss the transfer of responsibility for atomic energy research and development and weapons production from the Army to the civilian Atomic Energy Commission.

Despite management uncertainties and fluctuations, solid accomplishments in science and technology were achieved. Under the leadership of Eugene Wigner, Clinton Laboratories designed a high-flux Materials Testing Reactor, the precursor of all modern light-water reactors, and experimented with the Daniels Pile, a forerunner of high-temperature gas-cooled reactors. The first of thousands of radioisotope shipments left the Graphite Reactor in 1946, initiating a program of immense value to medical, biological, and industrial science. New organizational units were formed to study biology, metallurgy, and health physics, and several solid scientific accomplishments were recorded in these fields before the departures of Wigner and Monsanto. (See related article, Samuel Lind: Tennessee's Own.)

Management fluctuations proved a source of anxiety and despair among Laboratory staff during the 1947 Christmas season. By the start of the new year in 1948, however, crucial management decisions ensured the survival of Clinton Laboratories, which was given a much broader mandate for fundamental science than it had during the war. 


Charles Thomas served as Clinton Laboratories project director from 1945 to 1947.
Charles Thomas served as Clinton Laboratories project director from 1945 to 1947. He later became president of the American Chemical Society and the Monsanto Company.

During the war, security concerns required officials to refer to Clinton Laboratories by its code name, X-10. The personnel of Monsanto Chemical Company, the new operating contractor, continued this practice in the postwar years. The remote Appalachian location of Clinton Laboratories, along with unpaved streets and spartan living conditions, presented an easy target for ridicule. Metallurgical Laboratory personnel in Chicago called X-10 "Down Under," while Du Pont personnel labeled it the "Gopher Training School." In official telegrams, Monsanto's staff referred to Oak Ridge as "Dogpatch," taking their cue from Li'l Abner, a popular comic strip lampooning "hillbilly" Appalachian life. Such ill-concealed scorn did not bode well either for postwar Monsanto administration or Laboratory research. (See related article, From Installation Dog to Katy's Kitchen.)

The choice of Monsanto as contract operator of Clinton Laboratories seemed logical because of the Laboratories' focus on chemistry and chemical technology. Monsanto was also interested in becoming a key player in nuclear reactor development. Charles Thomas, Monsanto vice president, was the driving force behind the company's entry into nuclear science. A famous chemist, Thomas had established a laboratory at Dayton, Ohio, that Monsanto purchased in 1936, making it the company's central research laboratory. (See related article, Promethium Unbound: A New Element.)

In 1943, General Groves gave Thomas and Monsanto responsibility for fabricating nuclear triggers at the Dayton laboratory. When Thomas also agreed to supervise the operation of Clinton Laboratories in 1945, he merged both facilities into a single project and appointed himself project director, although he kept his main office at Monsanto's corporate headquarters in St. Louis.

James Lum became executive director of Clinton Laboratories in 1945.
James Lum became executive director of Clinton Laboratories in 1945.

When Whitaker and Doan left Oak Ridge, Thomas decided to establish a dual directorship at Clinton Laboratories with both directors reporting to him. For executive director in charge of general administration and operations, he selected James Lum, who had assisted him in managing the Dayton laboratory. As Lum's assistant, he brought in Prescott Sandidge, who had managed Monsanto phosphate and munitions plants.

Transferring 60 staff members to Oak Ridge from other Monsanto plants, Thomas reorganized the administration of Clinton Laboratories. Among the new administrators were plant manager Robert Thumser, shop and instrument superintendent Hart Fisher, chief accountant Clarence Koenig, and superintendent of support services Harold Bishop. Because many scientists returned to universities at the end of the war, Thomas and the Clinton staff also had to recruit replacements. Among the new staff members were Walter Jordan, P. R. Bell, and Jack Buck, who came from the radar laboratory at the Massachusetts Institute of Technology, and Ellison Taylor, Henry Zeldes, Harold Secoy, and Frank Miles, who came from the closed wartime laboratory at Columbia University.

 In 1947, under Monsanto's management, Clinton Laboratories employed 2141 workers, making building expansion imperative. A moratorium on new construction during 1946 and 1947, while the facility's future was debated in Washington, caused personnel and equipment to be moved into empty buildings at the Y-12 Plant, which was shifting its focus from the electromagnetic separation of uranium-235 to precision machining of weapons components.

Members of the 1946 management team—Frederick Seitz, James Lum, Eugene Wigner, and Alexander
Hollaender—hike a ridge overlooking the Laboratory.
Members of the 1946 management team—Frederick Seitz, James Lum, Eugene Wigner, and Alexander Hollaender—hike a ridge overlooking the Laboratory.

Expecting Clinton Laboratories to build the nation's first peacetime research reactor and the first electric power-generating reactor, Thomas courted Eugene Wigner, bringing him from Princeton to Oak Ridge several times during late 1945 to conduct seminars and consult on reactor designs. In early 1946, he lured Wigner into a year's leave from Princeton University to become Clinton Laboratories' research and development director by promising to relieve him of administrative duties, which Thomas assigned to James Lum. Wigner also acquired an assistant for the administration of research and development, Edgar Murphy, a scientist who had served as Army major in the Manhattan Engineer District office during the war.

When his Princeton colleagues asked Wigner why he was going to Dogpatch, he told them that, as one of the three major nuclear research laboratories in the United States, Clinton Laboratories would become important "in the life of the whole nation."

As its research director, he intended to focus on science education by (1) developing research reactors suitable for use at universities, (2) establishing nuclear science training under his former graduate student Frederick Seitz, and (3) coordinating scientific research with universities throughout the South. "Only too much have both Chicago and Oak Ridge lived in the past on fundamental knowledge that has been acquired either before the war or at one of the other government research centers," Wigner observed. "As these wells begin to run dry, this situation becomes increasingly unhealthy."

Early in his tenure, Wigner outlined his weekly routine. On Mondays, he would remain in his office with an open door to hear staff advice and grievances. On "Holy" Tuesdays, he would vanish, pursuing his own research to "keep my knowledge alive." Although he avoided committee meetings to the extent possible, the remainder of the week he would attend to duties, circulating through the Laboratories to discuss scientific and administrative problems. "We'll have long arguments just as you are having them now with each other," he warned the staff, "and I fully expect to be wrong in most of them—that is, from Wednesday to Friday."


This 1946 sketch was the first released by the Laboratory to explain to the public the proposed use of a nuclear reactor to generate electricity.

Miles Leverett helped lead the Oak Ridge team that designed the Materials Testing Reactor.
Miles Leverett helped lead the Oak Ridge team that designed the Materials Testing Reactor.

When Wigner arrived as research director, staff at Clinton Laboratories had begun designing new types of reactors. Researchers investigated the possibilities of developing a  high-neutron-flux reactor for testing materials and a gas-cooled Daniels Pile for demonstrating the use of nuclear energy for electricity production. The Laboratories' chemists also initiated research aimed at a high-flux homogeneous reactor.

Wigner devoted most of his attention to the high-flux reactor, subsequently renamed the Materials Testing Reactor. Its chief function was to bombard test materials with neutrons to determine which materials would be best for future reactors. A reactor designer's reactor, it provided the most intense neutron source at the time.

Initial designs called for use of enriched uranium fuel, heavy water in the interior lattice to moderate the neutrons, and ordinary (light) water to cool the exterior. Wigner and Alvin  Weinberg, appointed by Wigner to be Lothar Nordheim's successor as chief of physics, concluded that use of heavy water could severely reduce the flux of very fast neutrons.

Logan Emlet 
            of the Laboratory Operations Division inspects the toy engine that 
            used heat from the Graphite Reactor to demonstrate that nuclear power 
            could generate electricity.
Logan Emlet of the Laboratory Operations Division inspects the toy engine that used heat from the Graphite Reactor to demonstrate that nuclear power could generate electricity. 

Squeezing heavy water out of the reactor design, they selected ordinary water as both moderator and coolant. Instead of uranium rods canned in aluminum as in the Graphite Reactor, the fuel element or core would be uranium sandwiched between aluminum cladding or plates. To ensure a high thermal neutron flux for research, the plates were surrounded by a neutron reflector made of beryllium. In time, this design served as the prototype for many university research reactors and, in a sense, for all light-water reactors that later propelled naval craft and generated commercial power.

Miles Leverett and Marvin Mann headed a team of scientists and engineers who designed the Materials Testing Reactor at Oak Ridge. About 60 staff members became involved in the design over nearly six years.

Wigner's best-known contribution was the curved design of the aluminum fuel plates in the reactor core. These plates were placed parallel to one another with narrow spaces between for the cooling water; the reactor's power was largely set by how much water flowed past the fuel plates. Concern arose that intense heat might warp the plates, bringing them in contact and restricting coolant flow. After pondering this potential problem, Wigner directed that the plates be warped, or curved, to improve their structural resistance to stress. Because warped plates could only bow in one direction, they would not constrict water flow. 

Waldo Cohn inserts a sample in a graphite stringer that is then pushed into the Graphite Reactor for irradiation.
Step 1: Waldo Cohn inserts a sample in a graphite stringer that is then pushed into the Graphite Reactor for irradiation.
Irradiated materials are drawn from the Graphite Reactor.
Step 2: Irradiated materials are drawn from the Graphite Reactor.
Useful Radioisotopes are extracted by chemical processes and packed for shipment.
Step 3: Useful Radioisotopes are extracted by chemical processes and packed for shipment.

Adjacent to the Materials Testing Reactor, Leverett's team planned to construct a plant to reprocess spent nuclear fuel, using the precipitation process developed during the war. In reprocessing, nuclear fuel is extracted from the spent fuel and separated from the accumulated fission products for reuse in reactors. 

Chemists John Swartout and Frank Steahly recommended that the "25 solvent-extraction process" replace the more expensive precipitation process. Their recommendation was accepted.

Solvent extraction—separating one material from others dissolved in one liquid by transferring it into another liquid that cannot mix with the first—eventually became the standard method worldwide for reprocessing spent nuclear fuel.

Monsanto's principal concern was the Daniels Pile, named for Farrington Daniels who, at the Chicago Metallurgical Laboratory in 1944, had designed a reactor with a bed of enriched uranium pebbles moderated by beryllium oxide and cooled by helium gas. Some called it the pebble-bed reactor.

In May 1946, the Manhattan Engineer District directed Monsanto to proceed with the design, leading to the construction of an experimental Daniels Pile to demonstrate electric power generation. 

To accomplish this task, Monsanto brought Daniels from the University of Wisconsin as a consultant. The company also recruited engineers from industry and brought them to Clinton Laboratories, where they formed a Power Pile Division headed by Rogers McCullough. This division identified materials suitable for high-temperature reactors and developed pressure vessels and pumps, piping, and seals for high-pressure coolants; it also studied heat exchanger designs.

Because its staff was recruited largely from outside Clinton Laboratories, the Power Pile Division was never fully integrated into the organization. The project, moreover, encountered numerous design problems. Critics of the Daniels Pile contended that it would never become a practical power-generating reactor and that building a demonstration project wasted time and resources. After all, Logan Emlet and operators of the Graphite Reactor had demonstrated power production with a toy steam engine and generator that used heat from the air-cooled reactor. Why, critics said, should we pursue a more complicated and expensive power-production strategy?

Such criticism caused high-level support for the Daniels Pile to wane by 1948. It was never constructed, and Daniels, as a professor at the University of Wisconsin, would gain renown as a national expert on solar energy.


Distribution of the radioisotopes produced at the Graphite Reactor for biological and industrial research rapidly became the most publicized activity at Clinton Laboratories in the postwar years. (See related article, Radioisotopes and Health: Trace of Health.)

The Railway Express Agency trucks the 1000th shipment of radioisotopes from the Laboratory.
The Railway Express Agency trucks the 1000th shipment of radioisotopes from the Laboratory.

Orders began arriving soon after the Laboratory published a radioisotope catalogue in the June 1946 issue of Science, which listed isotopes Laboratory staff could prepare and ship. On August 2, 1946, Wigner stood in front of the Graphite Reactor to hand the first peacetime product of atomic energy, a small quantity of carbon-14, to an official of a cancer research hospital in St. Louis, home of Monsanto Chemical Company. Soon, nearly 50 different radioisotopes were regularly available for distribution. In 1947, to handle their production and distribution, Logan Emlet of Operations established an Isotopes Section headed by Arthur Rupp; as the program expanded, it later became the Isotopes Division, which was headed by Rupp and John Gillette, among others.

One of the earliest cases of technology transfer from Clinton Laboratories came as a spin-off of the radioisotopes program. Abbott Laboratories located its original radiopharmaceutical production plant in Oak Ridge near the source of the radioisotopes. The plant moved to Chicago in the 1960s when the Laboratory ceased commercial production of most radioisotopes.


Like most new managers, Wigner sought to sharpen the organization's mission and improve its performance. He made both minor changes, such as the appointment of Edward Shapiro as chief of the Laboratories' technical libraries, and major changes, such as forming and staffing new divisions. Thinking solid-state physics was a key to reactor design, Wigner established a small group for solid-state studies in the Physics Division under Sidney Siegel and Douglas Billington; he formed a new division to investigate the effects of radiation on metals; and he persuaded Monsanto executives to consolidate and augment staffing of the machine shops that supported the research projects.

During the war, small machine shops scattered among several divisions provided the tooling, finishing, and precision machine work required for scientific experimentation. In 1946, Wigner urged that these shops be merged into groups comprising at least 200 craftsmen. After some resistance to the suggestion, Executive Director James Lum established the central research shops in 1947 and imported Paul Kofmehl, a Swiss craftsman, as superintendent, with Earl Longendorfer as his assistant.

Ernest Sneed in the Laboratory's glass shop fabricates glassware for use in an experiment.
Ernest Sneed in the Laboratory's glass shop fabricates glassware for use in an experiment.

Skilled crafts people, who machined the hardware for the reactors and other projects, were put to work in the research shops. They acquired apprentices in the ancient tradition of the crafts and supplied scientists and engineers with the unique equipment and tools they required. As the work load increased, the research shops evolved into central machine shops and eventually became the Fabrication Department in the Plant and Equipment Division under the supervision of Robert Farnham. The shops even included an old-fashioned Tennessee blacksmith, Miller Lamb, who fabricated lead bricks for radiation shielding and produced customized nuts, bolts, and metal parts. Nearly a quarter century after Lamb retired in 1969, Laboratory personnel still pass his handiwork every day: he forged the ladder rungs on the smokestacks at the Laboratory.

In 1945, Miles Leverett purchased a secondhand mill to roll, cast, and forge reactor fuel elements and metal parts. He also recruited metallurgists for materials research. Declaring that "an integrated program on the properties and possibilities of materials from the structural and nuclear point of view is greatly to be desired," in 1946 Wigner hired William Johnson from Westinghouse as a consultant on the formation of a Metallurgy Division. Johnson recruited a half-dozen metallurgists to form the division under the leadership of John Frye, Jr.

Metallurgists faced the challenge of fabricating reactor components of uranium and aluminum alloys, beryllium, zirconium, and other exotic metals and conducted intensive research into the functioning of metallic elements under high temperatures and radiation stress in reactors. Starting with fewer than a dozen staff members, the Metallurgy Division increased to as many as 300 people. In 1952, Frye also organized a group under John Warde as a ceramics laboratory. In addition to conducting ceramics research, it fabricated crucibles, insulators, and fuel elements, and customized parts for reactors. The group also employed a practical potter or two to make molds. From these modest beginnings, the Laboratory would become a world center for metallic alloy and ceramics research.


Just as the atom's nucleus captivated physical scientists, the living cell was the center of attention for life scientists. The Graphite Reactor supplied a variety of radioisotopes that helped bring about a revolution in the life and medical sciences by leading to a new understanding of metabolic processes and genetic activities. Developments in biological sciences and the need to better understand the effects of radiation on human health and the environment led Wigner to expand the biology and health physics organizations.

When John Wirth, head of the Health Division, returned to the National Cancer Institute in September 1946, Wigner and Lum split the Health Division into two new research sections, plus a medical department, which was headed by physician Jean Felton and later by Thomas Lincoln and then Seaton Garrett. In October, Wigner recruited Alexander Hollaender to form and head a Biology Division. Hollaender had received degrees in physical chemistry from the University of Wisconsin. At the National Institutes of Health, he had studied the effects of radiation on cells and the use of ultraviolet light to control airborne diseases. (See related article, Alexander Hollaender: A Radiant Biologist.)

Hollaender's initial research plan at Clinton Laboratories called for studying radiation's effects on living cells, including such cell constituents as proteins and nucleic acids. 

Beginning with a few radiobiologists studying microorganisms and fruit flies in crowded rooms behind the dispensary, Hollaender initiated a broad program that would make his division the largest biological laboratory in the world. Hollaender would successfully unite fundamental research in the biological sciences with physics, chemistry, and mathematics and would recruit widely to staff the initial research units in biochemistry, cytogenetics, physiology, and radiology. William Arnold, Waldo Cohn, Richard Kimball, Elliot Volkin, and William and Liane Russell were among the Biology Division's most respected staff members, a group that included 70 scientists and technicians by 1947. Lacking space at the X-10 site, the new division moved into vacated buildings at the Y-12 Plant.

Researchers at Clinton Laboratories studied the responses of mice to varying amounts of
Researchers at Clinton Laboratories studied the responses of mice to varying amounts of radiation.

The biological research that attracted the most public interest was the genetic experiments conducted under the supervision of William and Liane Russell, who used mice to identify the long-term genetic implications of radiation exposure for humans. Among the division's early scientific accomplishments, however, Hollaender took special pride in William Arnold's discoveries of the electronic nature of energy transfer in photosynthesis, Waldo Cohn and Elliott (Ken) Volkin's discovery of the nucleotide linkage in ribonucleic acid (RNA), and Volkin and Larry Astrachan's discovery of messenger RNA.

The Biology Division's greatest long-term influence on science, however, may have come from its cooperation with the University of Tennessee-Oak Ridge Graduate School of Biomedical Sciences and with universities and research centers throughout the nation and the world.

The second division separated from the old Health Division in 1946 was Health Physics, directed by K. Z. Morgan. The Health Physics Division eventually included 70 staff members who monitored radiation levels in research and production areas and furnished improved radiation detection devices. Early research included studies of radioisotopes discharged into river systems, estimates of thermal neutron tolerances, and development of new methods to detect radiation. (See related article, Karl Z. Morgan: Man on a Mission.)

In 1944, Oak Ridge health physicists trained personnel responsible for radiation protection at Hanford. They continued this schooling at Oak Ridge until 1950 when the AEC established fellowships for graduate study at Vanderbilt and Rochester universities. The Army, Navy, and Air Force also sent personnel to receive health physics training at Oak Ridge. In addition to its land-based monitoring efforts, the Health Physics Division used boats to measure radioactivity entering the Clinch River from White Oak Creek and airplanes to monitor radioactivity in the air above Oak Ridge. As a result, the division was said to have its own "army, air force, and navy."

William Russell, who conducted pioneering studies of the mutagenic effects of environmental radiation and chemicals on mice.
William Russell, who conducted pioneering studies of the mutagenic effects of environmental radiation and chemicals on mice.

In late 1945, Martin Whitaker met with University of Tennessee officials to discuss a science education partnership that would allow young researchers to complete graduate studies at the university while working at Clinton Laboratories. This program was the precursor of an extensive cooperative graduate program with the University of Tennessee that has continued to this day.

In 1946, the Oak Ridge Institute of Nuclear Studies (ORINS), a nonprofit corporation of 14 southeastern universities, was chartered with William Pollard as its director. In 1947, the institute became an AEC government-owned, contractor-operated facility. Under its authority, Clinton Laboratories' Biology Division trained scientists in the use of radioisotopes. Later ORINS opened a clinical facility where radioisotopes were used for cancer treatment.

In 1949, the institute obtained support from the AEC to open the American Museum of Atomic Energy in a wartime cafeteria building. In 1974, the museum, renamed the American Museum of Science and Energy, moved into a new building adjacent to the corporate headquarters of the Oak Ridge Institute of Nuclear Studies, which itself had been renamed Oak Ridge Associated Universities and had nearly 50 sponsoring members.

Universities that joined the institute were invited to use the Laboratory's scientific facilities. Under the management of Russell Poor, the institute began a program for faculty research at the Laboratory in the summer of 1947 with two participants. That number increased to 70 by 1950, a level maintained for many years. Supplementing this research program were traveling lectures and seminars conducted by Laboratory scientists at the participating universities. The resulting interaction between Laboratory scientists and university faculty, along with faculty and student use of research equipment available at the Laboratory, contributed significantly to the spectacular growth in graduate science education throughout the Southeast during the postwar years.

William Pollard (center) and Gould Andrews, both of the Oak Ridge Institute of Nuclear Studies, welcome Eleanor Roosevelt to Oak Ridge.


In August 1946, Eugene Wigner opened the Laboratories' Clinton Training School with Frederick Seitz as its director. Although Wigner envisioned it as a small postdoctoral seminar in nuclear technology, more than 50 people from the military, industry, and academia enrolled. Among the first participants were Herbert MacPherson, Sidney Siegel, John Simpson, Everitt Blizard, Douglas Billington, and Donald Stevens, all of whom subsequently became renowned for their activities in science. The most famous graduate, however, was Captain Hyman Rickover of the U.S. Navy.

The Navy had first provided Wigner and Szilard funding for nuclear experiments in 1939. During the war, Navy scientists developed a thermal diffusion process for separating uranium isotopes; the S-50 plant in Oak Ridge was built during World War II for this purpose. Navy interest in using nuclear energy for ship propulsion continued, and in early 1946 Philip Abelson of the Navy research team spent several months at the Laboratory studying Wigner's approach to reactor design. In May 1946, Admiral Chester Nimitz assigned five Navy officers and three civilians to Oak Ridge. The officers were Hyman Rickover, Louis Roddis, James Dunford, Raymond Dick, and Miles Libbey. Rickover later recalled his Oak Ridge experience:

Frederick Seitz, who directed the Clinton Training School in 1946, became president of the
National Academy of Sciences and Rockefeller University.
Frederick Seitz, who directed the Clinton Training School in 1946, became president of the National Academy of Sciences and Rockefeller University.

When I started at Oak Ridge in 1946, there were 4 other naval officers along with me and 3 civilians. Each was sent to Oak Ridge individually, and each started working on his own. . .As soon as I got to Oak Ridge, I realized that if we ever were going to have atomic power plants in the Navy, I would have to assemble these people and train them as a group. And I used a very simple expedient; I arranged to write their fitness reports, so once they knew I was writing their fitness reports, they started paying attention to me. So once I did that, then I was able to weld them into a team and teach them specialized duties in order to get ready for building a submarine plant. Well, the first attempt at building a power plant at Oak Ridge was a civilian one, and it failed. Then unofficially I persuaded the people, the engineers, and the scientists, who were engaged in that enterprise, without any formal permission, to start working on a submarine plant, and they did this for a while. Meanwhile, I advised the Chief of the Bureau of Ships to retain this group of trained people together, and as soon as we came back to Washington, to have us start working on a submarine plant.

Under Rickover's exuberant direction, navy officers enrolled in the Training School attended every seminar, interviewed every scientist willing to talk, and wrote numerous reports that became the paper foundation of the nuclear navy. Rickover later chose the pressurized water reactor proposed by Alvin Weinberg to propel the nuclear ships built by the Navy. Legends about Rickover's activities at Clinton Laboratories still abound. For example, he sometimes elicited information from scientists by introducing himself: "I'm Captain Rickover; I'm stupid."

Everitt Blizard, an expert on radiation shielding.
Everitt Blizard, an expert on radiation shielding.

With the end of Monsanto management and the return of Wigner and Seitz to their universities in 1947, the Clinton Training School ceased to exist. Despite its brief tenure, the school was responsible for launching a long and fruitful relationship between the Navy and the Laboratory. Rickover entered into several nuclear design contracts with the Laboratory, and he often employed Laboratory scientists, such as Theodore Rockwell, Frank Kerze, and Jack Kyger, on Navy projects. Everitt Blizard, a civilian who had accompanied Rickover to Oak Ridge, remained at the Laboratory, where he supervised investigations of reactor shielding. Rickover sometimes advised Alvin Weinberg on Laboratory management. He also strongly supported the formation and subsequent educational work of the Oak Ridge School of Reactor Technology (locally dubbed the Klinch Kollege of Knuclear Knowledge) housed at the Laboratory between 1950 and 1965.


By his own account, Wigner's most troublesome problems as research director emanated from the Army bureaucracy. In the postwar years, the Army continued its wartime security policies. This meddlesome oversight made the exchange of scientific data with Hanford and Los Alamos difficult for Wigner and his research staff. This and similar problems caused Wigner to have several confrontations with Army authorities, notably Colonel Walter Leber.

Colonel Leber had replaced Captain James Grafton as the Army representative for Clinton Laboratories in May 1946, and he hired a large number of people to monitor its activities. His office staff included 22 people to inspect construction and administration, 3 to investigate security breaches, and 29 to examine research and development. This large group audited even minor details, down to the book titles ordered by the library. Their actions soon alienated both scientists and Monsanto executives, and James Lum strenuously objected to Leber's efforts to "interfere and assume responsibilities which are reserved only for Monsanto under the present contract." To reduce confusion and improve communications, Lum and Wigner asked Edgar Murphy, formerly an Army major, to serve as a liaison with Leber's staff.

Tensions continued, however, notably in the case of experiments Wigner wished to conduct to test the use of beryllium as a neutron trap or reflector. He encountered a "Catch 22" situation created by Leber's interpretation of a regulation the Army had imposed after Louis Slotin lost his life during a critical experiment at Los Alamos. Wigner insisted the tests were completely safe, but Leber required that the debilitating regulations, which brought the tests to a virtual standstill, be meticulously observed. Only after review at the highest level were the experiments allowed to continue. Such delays discouraged Wigner and in time caused him to return to university life.


"Speaking as individuals who have been interested in radiation effects on solids since the conception of the first large reactors," Wigner and Frederick Seitz wrote, "we find it gratifying that a phenomenon which originated as a pure nuisance promises to provide us with useful information about the solid state in general and about many of the materials we use every day."

By "nuisance," they meant the swelling and distortion of graphite under the bombardment of neutrons from nuclear fission, an effect predicted by Wigner and thus called the Wigner disease. Concern about the effects of this "disease" on the Graphite Reactor at Oak Ridge and similar reactors at Hanford stimulated intense interest in solid-state physics at Clinton Laboratories and elsewhere in the postwar years. This fascination played a role in Wigner's formation of the Metallurgy Division and in his personal attention to neutron scattering experiments and zirconium investigations.

Henry Pomerance uses a washing machine mechanism (called the pile oscillator) to oscillate
materials in and out of the Graphite Reactor for neutron irradiation.
Herb Pomerance uses a washing machine mechanism (called the pile oscillator) to oscillate materials in and out of the Graphite Reactor for neutron irradiation.

Although aluminum had served as cladding for uranium in the Graphite Reactor and other early reactors, it was not suitable for use in the high-temperature reactors designed in the late 1940s. Metallurgists considered substituting zirconium, a metal that resists corrosion in water at high temperatures. Zirconium, however, seemed to have a strong tendency to absorb neutrons, ultimately "poisoning" or slowing nuclear reactions.

In 1947, Wigner authorized a group of Laboratory researchers to study this problem. Wigner devised a "pile oscillator" to move materials regularly in and out of a reactor. Using a washing machine gearbox to power the oscillator, Herbert Pomerance later that year discovered that zirconium's capability for neutron absorption had been vastly overstated because of its contamination by the element hafnium, which had a much greater poisoning effect.

Zirconium minerals have traces of hafnium, whose chemical characteristics are nearly identical to zirconium's, making economical separation of the two difficult. With funding from Captain Rickover and the Navy, laboratory researchers across the country investigated ways to separate the two elements. In 1949, chemical technologists at the Y-12 Plant, under the direction of Warren Grimes, developed a successful separation technique and scaled it to production level under the direction of Clarence Larson, then superintendent of the Y-12 Plant. 

Zirconium alloys became essential first to the Navy's reactors and later to commercial power reactors. Zirconium rods filled with uranium pellets made up the fuel cores of nearly all light-water reactors, and hafnium was used in the control rods to regulate nuclear reactions.

As authorities on solid-state physics, Wigner and Seitz were intrigued by the interaction of radiation with materials, and especially by the neutron scattering experiments of the Laboratory's Ernest Wollan and Clifford Shull. With a modified X-ray diffractometer that Wollan installed at a beam hole of the Graphite Reactor in late 1945, Wollan and Shull systematically studied the fundamentals of thermal neutron scattering. Having difficulty making sense of the diffuse scattering from various forms of carbon—diamond dust, graphite powder, and charcoal—they called on Wigner for advice. (See related article, Ernest Wollan: Badge of Solid Distinction.) Shull later recalled:

I well remember a discussion that Ernie and I had with Eugene Wigner, then the research director of the laboratory and a physicist of infinite wisdom and physical intuition, about this puzzling feature. After listening to our tale of woe and reflecting on the problem, he surprised us very much by calmly suggesting "maybe there is something new here, and maybe we have to relax our notions about conservation of particles." I can only say that I came away from that meeting with the feeling that Wigner had more faith in our experiments than perhaps Ernie and I had!

After a few months of additional experimentation, Wollan and Shull recognized that the consistency of their data had been distorted by spurious multiple scatterings in the specimens being investigated, an effect unfamiliar to them. This finding allowed them to pursue their studies, which established neutron diffraction as a quantitative research tool fostering scientific knowledge of crystallography and magnetism. Their work built the foundation on which neutron scattering research developed throughout the world, including a neutron crystallography program under Henri Levy in the Chemistry Division at the Laboratory. Although a half-century has passed since the initial experiments, neutron scattering remains a fertile field of research.

he first two-axis diffractometer for neutron scattering research included an X-ray instrument that Ernest Wollan had used at the University of Chicago before bringing it to the Laboratory. Part of this instrument is displayed at the Smithsonian Institution.
The first two-axis diffractometer for neutron scattering research included an X-ray instrument that Ernest Wollan had used at the University of Chicago before bringing it to the Laboratory. Part of this instrument is displayed at the Smithsonian Institution. 


In late 1945, the War Department drafted a bill to continue military control of atomic research and energy. Atomic scientists at Chicago and Oak Ridge vigorously opposed the measure and formed associations to lobby for civilian control. After a protracted political battle, the Atomic Energy Act of 1946 established civilian control under a five-member commission. With David Lilienthal, formerly chairman of the Tennessee Valley Authority, as its first chairman, the AEC assumed control from the Manhattan District in January 1947. While this high-level political struggle was in progress, the disposition of the facilities built by the Manhattan District, including Clinton Laboratories, was at issue as well.

In early 1946, General Groves had appointed a committee of prominent scientists to plan the Manhattan District's nuclear activities and budget for 1947. Overall, the committee urged expansion of research and development for both production of fissionable materials and advancement of nuclear power. On the one hand, it suggested awarding contracts to university and private laboratories for unclassified basic research. On the other hand, it urged that national laboratories conduct classified research requiring equipment too expensive or products too hazardous for universities to handle. 

The first Atomic 
            Energy Commissioners.
The first Atomic Energy Commissioners. From left: William Waymack, Lewis Strauss, David Lilienthal, Robert Bacher, and Sumner Pike.

As the committee viewed it, each national laboratory should have a board of directors from universities in its region that would form associations to sponsor research and perhaps become the contracting operators. The committee initially recommended only two national laboratories, one at Argonne near Chicago and another serving the northeastern states. It expected the eventual formation of a national laboratory in California, but it ignored the Southeast and other regions.

Led by George Peagram and Isidor Rabi of Columbia University, universities in the northeast campaigned to acquire a national laboratory. The Radiation Laboratory at the Massachusetts Institute of Technology had closed at the war's end, and the Substitute Alloy Materials Laboratory at Columbia University had been moved to the K-25 Plant in Oak Ridge. Columbia and other northeastern universities urged the relocation of Clinton Laboratories to the Northeast, and some scientists at Clinton Laboratories liked the idea. More importantly, General Groves was amenable to it, and he selected an old Army post on Long Island as the future site of Brookhaven National Laboratory.

In April 1946, the University of Chicago agreed to operate Argonne National Laboratory, with an association of midwestern universities offering to sponsor the research. Argonne thereby became the first "national" laboratory. It did not, however, remain at its original location in the Argonne forest. In 1947, it moved farther west from the "Windy City" to a new site on Illinois farmland. When Alvin Weinberg visited Argonne's director, Walter Zinn, in 1947, he asked him what kind of reactor was to be built at the new site. When Zinn described a heavy-water reactor operating at one-tenth the power of the Materials Testing Reactor under design at Oak Ridge, Weinberg joked it would be simpler if Zinn took the Oak Ridge design and operated the Materials Testing Reactor at one-tenth capacity. The joke proved unintentionally prophetic.

Clinton Laboratories' rural ambiance did not please Robert Oppenheimer, Isidor Rabi, and James Conant, all influential members of the AEC's scientific advisory committee. Early in 1947, Oppenheimer declared that "Clinton will not live even if it is built up." Perturbed by this attitude, Charles Thomas of Monsanto demanded changes in Monsanto's operating contract at the Laboratories, in part as a sign that East Tennessee would be included in the federal government's postwar plans. On a no-profit, no-loss basis, the contract's chief attractions for Monsanto were the inside knowledge it provided of nuclear reactor advances and the public relations benefits it accrued for the company as a result of its patriotic efforts to protect the nation's security and advance the nation's technological capabilities.

Such virtues had their limits, especially when the war's outcome was no longer at stake. During negotiations to renew the contract in 1947, Thomas requested that Monsanto be allowed to increase its maximum fee for services from $65,000 a month to $100,000 a month. This request was not warmly received at the AEC; moreover, Thomas's request to build the Materials Testing Reactor near Monsanto's Dayton laboratory or near its corporate headquarters in St. Louis rather than Oak Ridge was also unacceptable. In May 1947, Thomas and Monsanto decided not to seek to renew the contract for operating Clinton Laboratories when it expired in June. The company, however, agreed to serve on a month-to-month basis until the AEC secured another contract operator.

Loss of the contract at Clinton Laboratories did not mar Charles Thomas's career. In early 1948, he signed a contract to operate the new AEC plant at Miamisburg near Dayton, later named Mound Laboratory. That same year, he was elected president of the American Chemical Society, and in 1951 he became president of Monsanto. His director at Clinton Laboratories, James Lum, left for Australia in August 1947 to build an aspirin factory. Thomas made Lum's assistant, Prescott Sandidge, the Laboratories' executive director, pending final contract closure. Colonel Walter Leber, temporary director for the Army, left in the summer of 1947 as well, later becoming Ohio River Division commander for the Corps of Engineers and governor of the Panama Canal Zone.

When Wigner returned to "monastic" life at Princeton University, also in the summer of 1947, Clinton Laboratories was left without a research director. Thomas decided to leave selection of Wigner's successor to the new contract operator. He asked Edgar Murphy, Wigner's assistant, to coordinate research pending selection of a new contractor and director.

Of his work at the Laboratory in 1946 and 1947, Wigner later lamented: "Oak Ridge at that time was so terribly bureaucratized that I am sorry to say I could not stand it. The person who took over was Alvin Weinberg, and he slowly, slowly improved things. I would not have had the patience."


Because the Argonne and Brookhaven laboratories would be operated by associations of universities, William Pollard and the Oak Ridge Institute of Nuclear Studies considered assuming Monsanto's contract. The AEC, however, preferred that the University of Chicago resume its operation of Clinton Laboratories, and it announced in September 1947 that a contract would be negotiated with Chicago. The university thereby would become contract operator of both the Argonne National Laboratory and Clinton Laboratories, which was renamed Clinton National Laboratory in late 1947 while negotiations with Chicago were under way.

Warren Johnson, wartime director of the Laboratory's Chemistry Division and later chairman of the University of Chicago's Chemistry Department.
Warren Johnson, wartime director of the Laboratory's Chemistry Division and later chairman of the University of Chicago's Chemistry Department.

The AEC was willing to enter a four-year contract with the university. Negotiations floundered, however, over the division of responsibilities between the university and the AEC for personnel policies, salaries, auditing, and oversight. Moreover, the university decided to recruit a new director and management team for the Laboratory, despite pleas for the return of Wigner. William Harrell, the university business manager, paraded prominent scientists to the Laboratory for orientation; but when offered the director's position, all demurred. Near the end of 1947, Warren Johnson, wartime chief of the Laboratory's Chemistry Division, agreed to serve as the interim director.

Concerned that the AEC's research program might become too academic, Lilienthal established a committee of industrial advisers, and during a November visit to Oak Ridge, he discussed with Clark Center, manager of Carbide & Carbon, a subsidiary of Union Carbide Corporation at Oak Ridge, the possibility of the company assuming management of the Laboratory. Union Carbide managed the nearby Y-12 and K-25 plants, and it already had a staff and offices in Oak Ridge that could easily add the Laboratory to their responsibilities. In addition, Union Carbide wanted to simplify its labor union relations. Workers at K-25 had joined the Congress of Industrial Organizations union, and craftsmen at the Laboratory had joined the American Federation of Labor union. A December 1947 strike over wages and benefits at K-25, which were lower there than at the Laboratory, threatened the company's tranquility and productivity. By assuming the Laboratory's management, Union Carbide possibly could abate labor tension.

With Lilienthal ill and bedridden and other AEC commissioners on holiday excursions, Carroll Wilson, the AEC's general manager, made the decision on Christmas Eve in 1947 to replace the University of Chicago with Union Carbide. At the same time, he decided to centralize all reactor development at Chicago's Argonne National Laboratory, transferring responsibility for Oak Ridge's high-flux Materials Testing Reactor there. 

The day after Christmas, the AEC concurred with these decisions. Wilson went to St. Louis to persuade Monsanto to hang on at Oak Ridge an additional two months until Union Carbide could become sufficiently organized for the task. The job of carrying the message to Oak Ridge fell to James Fisk, director of research, and he received the welcome one would expect for a bearer of ill tidings.

Remembered in the Laboratory long afterward as "Black Christmas," the shock came during the round of holiday parties. Reaction to the surprise was caustic. "Deck the Pile with Garlands Dreary," followed by several bawdy verses, reverberated through the halls. "It was rapid-fire and rough," admitted Lilienthal. He went on to say, "The people at Clinton Lab engaged in fundamental research felt they had been double-crossed, for we proposed to have Carbide & Carbon operate the lab (what was left of it, that is, minus the high-flux reactor), and this caused great anguish, not only among the chronic complainers but quite generally."

Laboratory staff declared the decisions represented a demotion from national laboratory status to a radioisotopes and chemical processing factory. Leaders of the Oak Ridge Institute for Nuclear Studies fired messages to President Truman and the AEC protesting the decisions as a blow to Southern scientific aspirations. This thinking ignored the AEC's promise to continue fundamental research at Clinton Laboratories, specifically in physics, chemistry, biology, health physics, and metallurgy. Rather than reducing the facility's status, in January 1948 the AEC changed its official name to Oak Ridge National Laboratory, ending the use of Clinton, which had been the nearest town during project construction.

The first impact of the decisions on the Laboratory was the transfer of the Power Pile Division, formed to study the Daniels pebble-bed reactor, to Argonne National Laboratory. Before leaving Oak Ridge, the division had begun studying Rickover's naval reactor. Harold Etherington, Samuel Untermeyer, and others in the group subsequently gained recognition for their designs of reactor 
prototypes for the atomic-powered Nautilus submarine and an early breeder reactor. 

Eugene Wigner and Alvin  Weinberg served successively as Laboratory research directors. Over the years, they became close friends and coauthored several publications.
Eugene Wigner and Alvin Weinberg served successively as Laboratory research directors. Over the years, they became close friends and coauthored several publications. 

The AEC never released a precise definition of "national laboratory." It granted the title, however, only to laboratories that engaged in broad programs of fundamental scientific research, had facilities open to scientists outside the laboratories, and cooperated with regional universities in extensive science education efforts. 

Oak Ridge clearly qualified for national laboratory rank, becoming one of three original national laboratories. Argonne and Brookhaven laboratories were built in 1948 on new sites, making Oak Ridge the oldest national laboratory on its original site. 

As these postwar manueverings suggest, Oak Ridge, located in the Appalachian Mountains far from the bright lights of any metropolis, has had to prove from its earliest days that its location was appropriate for its purpose. Surviving in an environment of political and administrative intrigue has required institutional perseverance and ingenuity—qualities that would serve the Laboratory's science and management well in the years ahead.

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