OAK RIDGE AND HANFORD
COME THROUGH
Oak Ridge (Clinton) and Hanford
(1944-1945)
Events: 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 right) 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.