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OAK RIDGE AND HANFORD COME THROUGH (Oak Ridge [Clinton] and Hanford, 1944-1945)
Events
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Bringing It All Together, 1942-1945
None of Los Alamos's bomb design work
would be of any use if Oak Ridge or
Hanford did not come through with enough
uranium-235 or
plutonium for at least one bomb.
Spending on the Manhattan Project reached $100 million per
month by mid-1944, yet it was still far from clear that
enough of either fissionable substance could be produced
before war's end. In the summer of 1944, Oak Ridge's
Y-12 Electromagnetic Plant (above) was
plagued by operational problems, and the
ongoing barrier crisis at the
K-25 Gaseous Diffusion Plant threatened
to render it useless. At Hanford, the
first production reactor had not yet been
completed. In addition, officials feared that not
enough of the uranium-containing slugs to feed the pile
would be available. Even assuming that enough
uranium or plutonium could be delivered by Oak Ridge or
Hanford, there was no guarantee that the Los Alamos
laboratory would be able to design and fabricate weapons
in time. Only the most optimistic in the Manhattan
Project would have predicted, as Groves did when he met
with Marshall in August of 1944, that a bomb or bombs
powerful enough to make a difference in the current war
would be ready by August 1, 1945.
During the winter of 1944-45, substantial progress was
made on uranium enrichment at Oak Ridge
thanks to improved performance at each of the major
production facilities. The increase in output also
had a lot to do with Kenneth Nichols's work in
coordinating a complicated feed schedule for the various
plants. As each of the three main processes --
electromagnetic (Y-12),
thermal diffusion
(S-50), and
gaseous diffusion (K-25) -- came on line,
they were used in tandem, with the slightly enriched
output from S-50 and K-25 ending up in Y-12 for final
processing. At Y-12, the nine Alpha and four Beta
racetracks, while not producing up to design potential,
were becoming significantly more reliable
because of maintenance improvements and chemical
refinements introduced by Tennessee Eastman. The
S-50 Thermal Diffusion Plant being built by the H. K.
Ferguson Company was almost complete and was already
producing small amounts of enriched material in the
finished racks. The K-25 Gaseous Diffusion Plant, complete
with barriers, was undergoing final leak tests. By
March 1945, Union Carbide had worked out most of the kinks
in K-25 and had started recycling uranium hexafluoride
through the system. S-50 was finished at the same
time that the Y-12 racetracks were demonstrating increased
efficiency. The Beta calutrons at the
electromagnetic plant were producing weapon-grade
uranium-235 using feed from the modified Alpha racetracks
and the small output from the gaseous diffusion and
thermal diffusion facilities. Oak Ridge was now
sending enough enriched uranium-235 to Los Alamos to meet
experimental needs.
To increase production, Groves proposed an additional
gaseous diffusion plant (K-27) for low-level enrichment
and a fourth Beta building containing two racetracks for
high-level enrichment, both facilities to be completed by
February 1946, in time to contribute to the war against
Japan, which many thought would not end before summer
1946. In short, by spring 1945 uranium enrichment
was still an enormously complicated and laborious process,
but it was clearly on the right track. "Little
Boy" (right), the atomic bomb
dropped on the Japanese city of Hiroshima
on August 6, 1945, contained uranium that had been
enriched at Oak Ridge. The uranium path to the
atomic bomb had indeed been proven viable and short enough
to result in a weapon before war's end.
At Hanford,
B Reactor was completed and began functioning in
September 1944. Although an unexpected problem with
xenon poisoning caused a delay of several
months, by early February 1945 the first plutonium
produced at B was on its way to Los Alamos. In
December 1944, D Reactor first went critical, and the
third and final reactor, F, began operation in February
1945. The amount of plutonium shipped to Los Alamos
grew rapidly over the spring and summer. From April
to May alone, plutonium production increased
five-fold. June production was even better, as was
July. By the end of August 1945, three plutonium
devices had been constructed at Los Alamos -- and two had
already been detonated, including one over the Japanese
city of Nagasaki. The
plutonium path to the bomb had proven
equally effective as the uranium one.
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Sources and notes for this page.
The text for this page was adapted from, and portions
were taken directly from the
Office of History and Heritage Resources
publication:
F. G. Gosling,
The Manhattan Project: Making the Atomic Bomb
(DOE/MA-0001; Washington: History Division, Department
of Energy, January 1999), 40-42. See also the History Office publication:
Richard G. Hewlett and Oscar E. Anderson, Jr.,
The New World, 1939-1946: Volume I,
A History of the United States
Atomic Energy Commission
(Washington: U.S. Atomic Energy Commission, 1972),
294-310, 374. Four devices were completed by the
end of August 1945: 1) the
implosion-type plutonium device tested
on July 16, 1945, at the Trinity Site; 2) the
gun-type uranium bomb ("Little
Boy")
detonated over Hiroshima
on August 6, 1945; 3) the implosion-type plutonium bomb
("Fat Man")
dropped on Nagasaki
on August 9, 1945; and 4) a fourth bomb, also an
implosion-type plutonium device, which
Leslie Groves reported to the War
Department would be available for use in the war by
about August 24. For more on the number and design
of nuclear weapons available following the end of the
war, see "The Manhattan Engineer District, 1945-1946." The photograph of the
Y-12 complex at
Oak Ridge is courtesy the
Lawrence Berkeley National Laboratory. The three diagrams illustrating methods of
uranium enrichment are reproduced from
the
Department of Energy
report
Linking Legacies: Connecting the Cold War Nuclear
Weapons Production Processes to their Environmental
Consequences
(Washington: Center for Environmental Management
Information, Department of Energy, January 1997), 138. The photograph of B Reactor under
construction is courtesy the
Hanford Site.
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