Y-12: CONSTRUCTION
Oak Ridge: Clinton (1943)
Events: The Uranium Path to the Bomb, 1942-1944

Groundbreaking for the Alpha plant of the Y-12 Electromagnetic Plant took place at Oak Ridge on February 18, 1943 (right).  Soon blueprints could not be produced fast enough to keep up with construction as Stone & Webster labored to meet Leslie Groves's deadline.  The Beta facility was actually begun before formal authorization.  While laborers were aggressively recruited, there was always a shortage of workers skilled enough to perform jobs according to the rigid specifications.  (A further complication was that some tasks could be performed only by workers with security clearances.)  Huge amounts of material had to be obtained (38 million board feet of lumber, for instance), and the magnets needed so much copper for windings that the Army had to borrow almost 15,000 tons of silver bullion from the United States Treasury to fabricate into strips and wind on to coils as a substitute for copper.  Treasury silver was also used to manufacture the busbars that ran around the top of the racetracks.  

Replacing copper with silver solved the immediate problem of the magnets and busbars, but persistent shortages of electronic tubes, generators, regulators, and other equipment plagued the electromagnetic project and posed the most serious threat to Groves’s deadline.  Furthermore, last-minute design changes continued to frustrate equipment manufacturers.  Nonetheless, when Ernest Lawrence (right) toured with Y-12 contractors in May 1943, he was impressed by the scale of operations.  Lawrence returned to the University of California, Berkeley rededicated to the "awful job" of finishing the racetracks on time.  

Lawrence and his colleagues continued to look for ways to improve the electromagnetic process.  Lawrence found that hot (high positive voltage) electrical sources could replace the single cold (grounded) source in future plants, providing more efficient use of power, reducing insulator failure, and making it possible to use multiple rather than single beams.  Meanwhile, receiver design evolved quickly enough in spring and summer 1943 to be incorporated into the Alpha plant.  Work at the Berkeley Radiation Laboratory picked up additional speed in March with the authorization of the Beta process.  With Alpha technology far from perfected, Lawrence and his staff now had to participate in planning for an unanticipated stage of the electromagnetic process.  

While the scientists in Berkeley studied changes that would be required in the down-sized Beta racetracks, engineering work at Oak Ridge prescribed specific design modifications.  For a variety of reasons, including simplicity of maintenance, Tennessee Eastman decided that the Beta plant would consist of two tracks of thirty-six tanks each in a rectangular, rather than oval, arrangement. Factoring this configuration into their calculations, Lawrence and his coworkers bent their efforts to developing chemical processing techniques that would minimize the loss of enriched uranium during Beta production runs.  To make certain that Alpha had enough feed material, Lawrence arranged for research on an alternate method at Brown University and expanded efforts at Berkeley.  With what was left of his time and money in early 1943, Lawrence built prototypes of Alpha and Beta units for testing and training operating personnel.  Meanwhile Tennessee Eastman, running behind schedule, raced to complete experimental models so that training and test runs could be performed at Oak Ridge.

But in the midst of encouraging progress in construction and research on the electromagnetic process in July came discouraging news from Robert Oppenheimer's isolated laboratory at Los Alamos, New Mexico.  Oppenheimer (right) warned that three times more fissionable material would be required for a bomb than earlier estimates had indicated.  Even with satisfactory performance of the racetracks, it was possible that they might not produce enough purified uranium-235 in time.  Lawrence responded to this crisis in characteristic fashion: he immediately lobbied Groves to incorporate multiple sources into the racetracks under construction and to build more racetracks.  Groves decided to build the first four as planned but, after receiving favorable reports from both Stone & Webster and Tennessee Eastman, allowed a four-beam source in the fifth.  Convinced that the electromagnetic process would work and sensing that estimates from Los Alamos might be revised downward in the future, Groves let Lawrence talk him into building a new plant -- the Y-12 Extension –- doubling, in effect, the size of the electromagnetic complex. The Alpha component of the Y-12 Extension, Groves reported to the Military Policy Committee on September 9, was designated as Alpha II and would consist of two buildings, each with two rectangular racetracks of ninety-six tanks operating with four-beam sources. Also authorized was a second Beta building containing two racetracks. Improvisation remained the key word at Oak Ridge.