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As problems with both Y-12
and K-25 reached crisis proportions in the spring and summer of 1944,
the Manhattan Project received help from an unexpected source - the
United States Navy. President Roosevelt had instructed that the
atomic bomb effort be an Army program and that the Navy be excluded
from deliberations. Navy research on atomic power, conducted
primarily for submarines, received no direct aid from Groves, who, in
fact, was not up-to-date on the state of navy efforts when he received
a letter on the subject from Oppenheimer in April 1944.
Oppenheimer informed Groves
that Philip Abelson's experiments on thermal diffusion at the
Philadelphia Navy Yard deserved a closer look. Abelson was
building a plant to produce enriched uranium to be completed by early
July 1944. It might be possible, Oppenheimer thought, to help
Abelson complete and expand his plant and use its slightly enriched
product as feed material for Y-12 until the problems plaguing K-25
could be resolved.
The liquid thermal
diffusion process had been evaluated as early as 1940 by the Uranium
Committee, when Abelson was still with the National Bureau of
Standards. In 1941 he moved his research to the Naval Research
Laboratory, where there was more support for his work. During
the summer of 1942 Bush and Conant received reports about Abelson's
research but concluded that it would take too long for the thermal
diffusion process to make a major contribution to the bomb effort,
especially since the electromagnetic and pile projects were making
satisfactory progress. After a visit with Abelson in January
1943, Bush encouraged the Navy to increase its support of thermal
diffusion. A thorough review of Abelson's project early in 1943,
however, concluded that thermal diffusion work should be expanded but
should not be considered as a replacement for gaseous diffusion, which
was better understood theoretically. Abelson continued his work
independently of the Manhattan Project. He obtained
authorization to build a new plant at the Philadelphia Navy Yard,
where construction began in January 1944.
(Webmaster's Note: The Navy, and
specifically the Philadelphia Navy Yard, was chosen by Abelson because
of their experience dealing with huge ship boilers which produced
steam. Steam was the essential source of heat required for the
liquid thermal diffusion process.)
Groves immediately saw the
value of Oppenheimer's suggestion and sent a group to Philadelphia to
visit Abelson's facility. A quick analysis demonstrated that a
thermal diffusion plant could indeed be built at Oak Ridge and placed
in operation by early 1945. The steam required in the convection
columns was already at hand in the form of the almost completed K-25
powerplant (The largest in the world). It would be relatively
simple to provide steam to the thermal diffusion plant and produce
enriched uranium, while providing electricity for the K-25 plant when
it was finished. Groves gave the contractor, the H. K. Ferguson
Company of Cleveland, just ninety days from September 27 to bring a
2,142 column plant on line (In comparison, Abelson's plant in
Philadelphia contained 100 columns). There was no time to waste
as Happy Valley in Oak Ridge braced itself for a new influx of 10,000
workers.
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