Britannica Sources used in this answer

How did the Manhattan Project produce uranium and plutonium for atomic bombs?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

U.S. hydrogen bomb test in the Marshall Islands — nuclear weapon A test of a U.S. thermonuclear weapon (hydrogen bomb) at Enewetak atoll in the Marshall Islands, November 1, 1952.

The Manhattan Project utilized distinct physical and chemical processes to produce the fissionable materials required for atomic bombs.

Uranium-235 Production

Because uranium-235 cannot be separated from uranium-238 through chemical means, the project employed physical separation methods at Oak Ridge, Tennessee:1
* Electromagnetic separation: Developed under Ernest Orlando Lawrence, this method used electromagnetic fields to separate isotopes.1
* Gaseous diffusion: Developed under Harold C. Urey, this complex process was the primary method for large-scale separation.1
* Thermal diffusion: A third method developed by Philip Hauge Abelson was used for preliminary separation.1

Plutonium-239 Production

Plutonium-239 was synthesized at the Hanford Engineer Works in Washington through the transmutation of uranium-238 within large-scale nuclear reactors. After the uranium underwent a chain reaction, it was removed from the reactors and processed in chemical separation plants—referred to as "canyons"—to extract the plutonium. This material was then sent to Los Alamos for final weapon fabrication.12