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Chapter 3: Accelerating Projects

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CLARENCE LARSON: THE RIGHT CHEMISTRY

Clarence Edward Larson, a former ORNL director, distinguished himself both as a chemical engineer and leader of scientific activities of vital interest to the United States. 

A native of Minnesota who completed undergraduate work in chemistry and chemical engineering at the University of Minnesota, he received his Ph.D. degree in biochemistry in 1937 from the   University of California at Berkeley. While a graduate student, he experimented with cyclotron-produced isotopes obtained from cyclotron inventor Ernest O. Lawrence. 

Clarence Edward Larson

In 1937, Larson joined the Chemistry Department of the College of the Pacific, later becoming department chairman. He continued experiments using cyclotron-produced isotopes and, as a result of this work, joined Lawrence in the Manhattan Project in 1942. His responsibility was to solve the chemical problems associated with electromagnetic separation of fissionable uranium-235 from the more abundant nonfissionable uranium isotope. The calutrons used for this process were designed and built under Lawrence's leadership. 

One chemical problem was that the calutrons directed the uranium beam against the walls of the steel-and-graphite receivers with such energy that the uranium atoms buried themselves in the stainless steel, greatly reducing the amount of enriched uranium that could be recovered. Larson suggested that the embedded uranium could be easily recovered from the receiver walls if they were plated with copper. Lawrence liked the idea and demanded that Larson assemble a team to copperplate the receivers and put the process into operation in one day. "Fortunately," Larson said recently, "the equipment was available and, on the next day, the operations started successfully." 

Another problem was to recover the uranium scattered all over the calutron interiors. Because of the extremely corrosive conditions, large amounts of impurities entered the solutions, making recovery of the uranium difficult. It was known that uranium could be precipitated selectively by hydrogen peroxide, but this recovery system, says Larson, "was almost explosively unstable because of the catalytic effects of the impurities." Recalling that many  unstable biological compounds can be prevented from decomposing if subjected to frigid conditions, Larson devised double-walled vessels containing a cooling system for the uranium precipitation system. "This system," Larson says, "worked successfully throughout the project. By fortunate coincidence both of these process problems were solved by applying electrochemical and separations techniques used in my graduate research." 

In 1948, Larson became director of the Y-12 Plant, and in 1950 he became director of Oak Ridge National Laboratory. Larson presided over the Laboratory's $20-million expansion program involving completion of nine new buildings, large-scale modification of four buildings, and acquisition of space for ORNL activities at the Y-12 Plant. Under his administration, the Bulk Shielding Reactor, the Homogeneous Reactor Experiment, and the Aircraft Reactor Experiment   began operation and the Tower Shielding Facility was completed for the Aircraft Nuclear Propulsion Program. The Laboratory's first large computer was installed, and an ORNL reactor exhibit received  rave reviews at the first "Atoms for Peace" conference in Geneva, Switzerland. 

In 1955, Larson left Oak Ridge to become vice president of the National Carbon Division of Union Carbide Corporation. Later he became deputy manager of corporate research there. In 1961, he returned to Oak Ridge, where he served as president of Union Carbide Nuclear Division until 1969. In this capacity, he oversaw management of ORNL, the Y-12 Plant, and the Oak Ridge and Paducah gaseous diffusion plants for the Atomic Energy Commission (AEC). From 1969 through 1974 he was an AEC commissioner, the only person from Oak Ridge to attain this position. In 1973, Larson was elected to the National Academy of Engineering for "the development of processes for recovery and purification of uranium and leadership in nuclear plant design." 

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