A diamond in Dogpatch: The 75th anniversary of the Graphite Reactor Part 2: The Postwar Years
Following World War II, the Graphite Reactor was the foundation upon which Oak Ridge National Laboratory was built, and it gave birth to many of the technologies we take for granted in the 21st century.
By Sherrell R. Greene sions accomplished, however, the futures of the Met Lab and Clinton Labs were in art 1 of this article described a se- doubt. Clinton had an ace in the hole—the ries of unlikely events that resulted Graphite Reactor—a tool that had already Pin the construction of the Graphite shown itself to be a remarkably versatile Reactor in the hills of East Tennessee in a vessel for probing the New World. The location so remote that the Met Lab scien- wizards at Clinton would waste no time in tists and others in the Manhattan Project finding additional uses for it. dubbed it “Dogpatch.” Indeed, almost ev- During the later months of 1944 through erything about the Graphite Reactor story the summer of 1945, scientists at Clinton could be characterized as “unlikely”—its converged on a strategy for the lab’s post- location, the partnership between the sci- war role in the New World. Their strategy entists at the Chicago Met Lab and DuPont was built around two central themes: (1) that produced a remarkably simple but ca- exploitation of the Graphite Reactor and pable machine, the incredibly short con- the scientists’ radiochemical separations struction schedule, its trouble-free startup expertise; and (2) the development of new Graphic: ORNL and operation, and its contributions to the “piles” with different fuel cycles and ex- The original Oak Ridge National success of the Manhattan Project. Part 2 of panded capabilities for research and for Laboratory logo, 1948–1974. the story focuses on the Graphite Reactor’s the production of electricity and process unlikely post–World War II roles in the heat for civilian applications. Alamos, as well as the (newly created) birth of Oak Ridge National Laboratory The Graphite Reactor would anchor a Brookhaven Laboratory, as “national (ORNL), the advent of “Big Science,” and multifaceted program of radioisotope pro- laboratories.” Clinton Laboratories was the evolution of nuclear technology as one duction, together with basic and applied designated by the AEC as Oak Ridge of the key enablers of modern life. research in the biological, medical, and National Laboratory on March 1, 1948, health physics arenas; materials science; as operating responsibility for the lab Anchoring ORNL’s birth chemistry and radiochemistry; neutron transitioned from Monsanto (which had The end of World War II left both the science; and physics. This strategy would assumed responsibility for the operation Met Lab in Chicago and Clinton Labora- be the polestar of ORNL’s mission until of Clinton Labs in July 1945) to Carbide tories at Oak Ridge in the classic “ham- the mid-1970s. The role of the Graphite and Carbon Chemicals Company (later mer-in-search-of-a-nail” dilemma. Han- Reactor in ORNL’s birth and postwar suc- Union Carbide). It was time to leave the ford’s plutonium production mission cess was reflected in the fact that an artist’s beaches and move inland to explore the would continue. Los Alamos’s mission rendering of the Graphite Reactor served interior of the New World. would continue. With their original mis- as ORNL’s official logo until 1974, over a decade after the reactor had shut down. Beyond the bomb Sherrell R. Greene (
28 • Nuclear News • December 2018 www.ans.org/nn A diamond in Dogpatch: The 75th anniversary of the Graphite Reactor sought to distinguish between the effects of fast neutrons, slow neutrons, and gam- ma radiation. It was from this work that the original “LD 50” guidelines for lethal radiation dose in humans were developed. The Graphite Reactor’s contributions to reactor technology include the first use of two-group neutron transport (diffusion theory) to design a reactor lattice; the first operation of a nuclear reactor at tempera- tures sufficiently high to “see” the reactiv- ity temperature feedback effect; the first fabrication and use of sealed nuclear fuel elements; the first natural uranium–water lattice experiments (which provided the basis for early light-water reactor designs); the first demonstration of water tank shields (which provided the motivation for the ubiquitous pool-type research reactors constructed around the world in the 1950s
Photo: DOE/Ed Wescott and 1960s and information used in the de- The first delivery of the medical radioisotope carbon-14 to the Barnard Free Skin and sign of early naval reactor shields); the first Cancer Hospital in St. Louis, Mo., on August 2, 1946. use of experimental reactivity oscillator devices; and the discovery of the low-cap- Alvin Weinberg famously stated, “If at togenetic/chromosomal mutation) effects ture cross section of zirconium (which some time a heavenly angel should ask of slow neutrons and from which mod- became the standard fuel cladding for the what the laboratory in the hills of East ern-day boron neutron capture therapy world’s commercial nuclear power fleet). Tennessee did to enlarge man’s life and was developed. If you or someone you Fuels for homogeneous and molten-salt make it better, I daresay the production know has undergone a nuclear medicine reactors were first tested in the Graphite of radioisotopes for scientific research procedure, it’s quite likely that the radio- Reactor. The use of pneumatic tubes, or and medical treatment will surely rate as isotopes and technologies employed trace “rabbits” (a now-common design feature a candidate for first place.” their history to the Graphite Reactor. of research reactors worldwide), for the In June 1946, ORNL (still Clinton Labs Plans for the use of the Graphite Reac- insertion and retrieval of material sam- at the time) published a notice in Science tor to explore the effects of radioactivity ples while the reactor was operating was magazine announcing that some 20 fission on organisms were in place at the Clinton perfected at the Graphite Reactor. product isotopes and 60 nonfission prod- Pile by April 1943. Those plans included One would be remiss to overlook the uct isotopes would be available to research- both the impact of radiation from external world’s first production of electricity ers and the medical community. The first sources, from inhaled and ingested radio- from nuclear energy, which occurred at commercial shipment of radioisotopes— active species, and studies of how radio- the Graphite Reactor in September 1948, 1 millicurie of carbon-14 to the Barnard active species are metabolized in mam- when researchers connected a tabletop Free Skin and Cancer Hospital in St. Lou- mals (specifically mice and rabbits). Many Jensen #50 steam engine/generator to a is, Mo.—occurred on August 2, 1946. of the studies involved the irradiation of simple steam generator driven by 10 fuel In its first year of production, the mice in the “animal tunnels” at the top slugs in the pile. The electricity powered Graphite Reactor produced material for of the reactor (NN, Nov. 2018, p. 40) and a small flashlight bulb. Although appar- over a thousand shipments of radioiso- topes. Demand was particularly high for carbon-14, iodine-131, and phospho- rus-32, which would become a work- horse radioisotope for mapping metabolic pathways and labeling DNA. By the end of 1951, the lab had made nearly 30,000 shipments of radioisotopes. By the time the Graphite Reactor shut down in 1963, over 27 kg of technetium (Tc-99m is the most frequently used radionuclide in nu- clear medicine) had been shipped from the lab. Over the course of its lifetime, the Graphite Reactor and its associated radio- chemical processing facilities served as an “atomic apothecary,” producing over 200 different radioisotopes (many synthesized for the first time at Oak Ridge) for medical treatments, industrial applications, and scientific research. It was also in the Graphite Reactor that the experiments were done that demon-
strated the major role boron content Photo: DOE/Ed Wescott played in determining the biological (cy- The first electricity is generated from nuclear power, September 1948.
December 2018 • Nuclear News • 29 ently done more for entertainment value than anything else, the stunt was the first conversion of nuclear energy to electrical energy. (The steam engine used in the “ex- periment” is on display in the viewing gal- lery of the Graphite Reactor today.) Finally, it is no stretch to claim that the modern disciplines of nuclear engineering (reactor and radiochemical engineering) were birthed in the effort to design, build, and operate the Oak Ridge Pilot Plant (the Graphite Reactor and its companion ra- diochemical separations facility). The Graphite Reactor functioned as a transformational analytical instrument almost from the moment of its initial criticality. It was the first reactor used for neutron activation analysis—a powerful analytical tool for discerning the elemen- tal composition of unknown materials. The reactor was being employed before the
end of 1943 to scan for potential neutron Photo: DOE/Ed Wescott activation problems that might be present- Ernest Wollan and Clifford Shull with their double-crystal neutron spectrometer at the ed by the materials (including water) to be face of the Graphite Reactor in 1949. used in the construction and operation of the Hanford reactors. It was at the Graph- ginning in 1944, work recognized with the state” irradiation experiments aimed at ite Reactor that Ernest Wollan and Clifford Nobel Prize in Physics in 1994. understanding the effects of radiation on Shull conducted their pioneering neutron The Graphite Reactor was employed nonbiological matter. Pioneering studies scattering/neutron diffraction studies be- during its lifetime for thousands of “solid- were conducted there on the effect of irra- diation on semiconductors, work that en- abled early spacecraft and satellite systems. In addition to the early neutron activa- tion analyses noted above, the reactor was pressed into service in 1943–1944 to pro- vide understanding of the impact of neu- tron irradiation on the physical proper- ties (for example, strength, hardness, and elasticity) of structural materials used in reactor construction. In 1956, researchers installed a helium-cooled cryostat in hole No. 12 of the Graphite Reactor, the first irradiation facility at an operating reactor that allowed neutron bombardments of material samples at liquid hydrogen tem- peratures. This work produced the first data on fast and slow neutron radiation damage mechanisms in metals and other materials irradiated at temperatures be- low 20 K. The refrigeration system for the cryostat was a pathfinder for today’s cold neutron source systems in neutron scatter- ing research at reactors around the world. (In a nod to the then popular and now im- mortal movie starring Humphrey Bogart and Katherine Hepburn, the refrigeration system was promptly dubbed the “African Queen” due to the similarity of the sound it emitted during operation to that of the little steam boat piloted by Bogart’s char- acter, Charlie, in the 1951 movie.) Mission accomplished The Graphite Reactor was permanently shut down on November 4, 1963, 20 years to the day after it first came to life. With Photo: ORNL a push of a button, Richard L. Doan, the At the Graphite Reactor shutdown ceremony, from left, Richard Doan, Alvin Weinberg, first research director of ORNL, gave the and Glenn Seaborg, November 4, 1963. command for the control rods to drive
30 • Nuclear News • December 2018 www.ans.org/nn A diamond in Dogpatch: The 75th anniversary of the Graphite Reactor into the old graphite core for the very last time. Glenn Seaborg, Eugene Wig ner, Alvin Weinberg, and a host of other dignitaries shared the speaker’s platform in front of the reactor that afternoon. As reported in ORNL’s employee newspaper, The News, “The crowd . . . filled the old pile building to overflowing. People lined the stairs, the hallways, even the top of the reactor itself to watch the ceremonies.” Visitors to ORNL that day were treated to speeches by the dignitaries and tours of the Gas Cooled Reactor, the Health Phys- ics Reactor, the Molten Salt Reactor, the Tower Shielding Facility, the Oak Ridge Research Reactor, and the High Flux Iso- tope Reactor (then under construction), each of which could in some way trace its lineage to the Graphite Reactor. The following morning, Wigner received the news that he would share that year’s No- bel Prize in Physics for “his contributions to the theory of the atomic nucleus and Photo: ORNL elementary particles.” It was somehow all The Graphite Reactor building as it appears today. fitting and proper. The scene of November 4, 1963, was and technicians, the reactor lays claim to cal tools of the 20th century. It was the largely repeated three years later, on Sep- worldwide alumni, and the number of ex- foundation upon which one of the world’s tember 13, 1966, when the ORNL Graph- periments and irradiations hosted over the great scientific laboratories was built. It ite Reactor was designated a National years within its core are legion. . . . More was arguably the first “Big Instrument” Historic Landmark in a ceremony headed efficient reactor systems . . . were the direct of “Big Science.” Seventy-five years after by Seaborg, then chairman of the AEC, outgrowth of technology developed by this it began operation and 55 years after its and Wigner, a former research director now-famous reactor. Even the modern nu- shutdown, no other nuclear reactor in the at ORNL, along with Weinberg, director clear power plants of today have an ances- world can boast an equally impressive list of ORNL, and a host of other notables. try traceable to the X-10 pile.” of accomplishments. Weinberg, the man Wigner credited with Speaking last, Wigner noted the unique Indeed, the Oak Ridge Graphite Reactor having single-handedly created the nucle- role the reactor played as the first catalyst was an incubator of the nuclear age. ar design of the Graphite Reactor, opened for collaboration between nuclear scien- the ceremonies. Speaking affectionately of tists and engineers and emphasized the re- the reactor, Weinberg referred to it as “an actor’s role as a “cohesive force for a large Author’s postscript old Oak Ridge friend” and “a beloved re- laboratory in which a great variety of tal- It is impossible to do justice to actor.” He recounted many of its exploits ents and human strengths and weaknesses the history of the Graphite Reactor and emphasized its role for more than 20 work side by side.” He added that this lat- in this two-part article, much less years as “an early symbol of Big Science,” ter role “may have been fully as important to pay due respect to the hundreds saying, “This lady needs nothing more to as its other functions.” of distinguished Graphite Reactor establish her immortality.” The most poignant comments that day “alumni.” The list of individuals who Seaborg, in accepting the National His- were offered by Seaborg, who ended his were involved in some manner with toric Landmark plaque from Elbert Cox, speech with the following words, which the Graphite Reactor and the Pilot regional director for the National Park perhaps best summarize the legacy of the Plant is a virtual “Who’s Who” in Service, recounted the reactor’s Manhat- Oak Ridge Graphite Reactor: “From its the annals of 20th century nuclear tan Project contributions and emphasized secret birth to its reluctant retirement, the science and engineering. It includes its postwar role as a source of radioisotopes Graphite Reactor contributed immeasur- Arthur Compton, Crawford Green- for a multitude of applications, adding, “As ably to the defense of this nation’s liberty, walt, Ernest Hollander, Miles Lever- a training instrument for reactor operators and to the betterment of man’s everyday ett, Karl Morgan, Hyman Rickover, life. Most assuredly, the X-10 Reactor oc- Theodore Rockwell, Glenn Seaborg, cupies a unique niche in the annals of Frederick Seitz, Clifford Shull, Louis Visiting the American history.” Slotin, Katherine Way, Alvin Wein- The knowledge and technologies that berg, Martin Whitaker, Eugene Graphite Reactor emerged from the Graphite Reactor be- Wigner, Ernest Wollan, Gale Young, The Oak Ridge Graphite Reactor tween November 1943 and November and a host of others. Some helped is one of eight Signature Facilities of 1963 touch our lives today in a multitude birth the reactor and the Pilot Plant. the Manhattan Project National His- of ways. Beyond its role in the Manhattan Some harnessed its amazing capabil- torical Park. It is open for public bus Project, the Graphite Reactor’s contribu- ities. Some spent days at the Graphite tours from March through Novem- tions in such diverse fields as reactor en- Reactor; others spent decades there. ber. Those wishing to visit the reactor gineering and technology, physics, chem- It is to that generation of giants, who must register in advance at
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