The Manhattan Project, Brave New World
The Manhattan Project to develop an atomic bomb began in earnest in late 1942 with the appointment of Gen. Leslie Groves to spearhead the effort. At that time there was a growing scientific consensus that such a bomb might be possible, but no one knew how best to proceed. Bombs might be based on a rare isotope of uranium, the heaviest commonly occurring element, or on a newly discovered element, plutonium that would have to be manufactured. Because of fears that Nazi scientists were working toward such a weapon, Groves decided to pursue both possibilities simultaneously and was given virtually unlimited procurement authority. Three years and two billion dollars later, a plutonium bomb was successfully tested in the badlands of New Mexico, an untested uranium bomb was dropped on Hiroshima, and a plutonium bomb was dropped on Nagasaki. The Japanese surrendered. But the curtain was now lifted, and civilization would soon have to cope with the unprecedented and awesome power to destroy itself. In this series of images are some of the signature facilities of the Manhattan Project.
Clinton Engineering Works (later Oak Ridge), TN, was the site of several industrial plants to concentrate the rare uranium isotope, U235 from the more abundant U238. Electromagnetic separation was accomplished using machines known as calutrons at the code-named, Y-12 site. U235 was also concentrated by gaseous molecular diffusion at the K-25 plant, a U-shaped building nearly a mile around, enclosing hundreds of miles of piping, and the largest building in the world at the time of its construction. K-25 was followed by K-27 in early 1946, then by K-29 and K-31 in 1951 and K-33 in 1954. All of these buildings were eventually linked by heated pipes to form a massive continuous-stream operation. The S-50 Plant, dismantled shortly after the war, used a third method, liquid thermal diffusion, to separate U235. All three methods contributed to the U235 employed in the Hiroshima bomb. The X-10 graphite reactor provided research quantities of plutonium and served as a subscale plant for the main production reactors and chemical separation plants in Hanford, Washington.
Plutonium was created on an industrial scale during the Manhattan Project at the Hanford Engineering Works (later the Hanford Nuclear Reservation), WA, in B, D, and F Reactors by bombarding U238 with neutrons originating from fission of U235. After a time in the water cooled reactors, the fuel slugs of natural uranium metal are partially converted to plutonium and many highly radioactive fission products. These irradiated slugs were first cooled in a water pool at the reactor, then transported by special rail cars to a special storage building where the hot fission products were allowed to decay further. They were then again transported by the special rail cars to the chemical separation buildings, T and B Plants, where a series of chemical steps separated the plutonium from U238, U235, and the still dangerous fission fragments - all by remote control. The refined plutonium was then stored at the Gable Mountain Vaults before final transfer to Los Alamos for bomb assembly. During the Cold War six more reactors were built; all are now deactivated and some have been "cocooned" to minimize further spread of radioactive contamination. The current mission of Hanford is to minimize the future consequences of almost 40 years of plutonium production; it is impossible to restore the land to its former state.
Bomb design and assembly of both uranium and plutonium weapons took place at Los Alamos, NM. Confidence that the uranium bomb would work was so high and the supply of U235 so meager that it was not tested before use on Hiroshima on August 6, 1945. The plutonium test bomb, known as the "gadget" was successfully detonated in the New Mexico desert on July 16, 1945, and a weaponized version dropped on Nagasaki on August 9, 1945.
The generous cooperation of the Department of Energy and its contractors in enabling access to these still-sensitive sites is gratefully acknowledged. In particular, I thank Walter Perry and Lynn Freeny (Oak Ridge Office, DOE); Dennis Hill and Dave Lannom (Bechtel-Jacobs Co. LLC); Steve Goodpasture (CDM Federal Services Inc.); Ray Smith, Kathy Fahey, and Bill Chappell (B&W Y-12); Bill Cabbage (ORNL); Todd Nelson (Washington Closure Hanford); and Michelle Gerber (Fluor Hanford). I also extend special thanks to Cindy Kelly, President of the Atomic Heritage Foundation.