In 1942, the Manhattan Project needed to create a chain reaction—a crucial step toward proving that it would be possible to make an atomic bomb. The scientists achieved this sustained nuclear reaction, the first created by humans, on Dec. 2, 1942, in a squash court under the stands of Stagg Field at the University of Chicago.
Nicknamed “Chicago Pile-1,” the world’s first nuclear reactor kicked off the Atomic Age and has a complicated legacy, including the rise of both nuclear energy and nuclear weapons.
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How did the first nuclear reactor come to be?
As physicists came closer to understanding the nature of the atom in the 1930s, it became increasingly clear that a great deal of energy could be released by splitting atoms. In 1939, Albert Einstein and Leo Szilard co-wrote a letter to U.S. President Franklin D. Roosevelt, explaining that the discovery could be made into a powerful weapon, and that Nazi scientists likely had the tools to do so.
That kicked off the United States’ Manhattan Project, a top-secret scientific mission to learn how to split the atom and harness its power. But one of the first things on the list was to learn whether it was possible to create and control a nuclear chain reaction at all.
The Project decided to consolidate this effort in one location. Because Chicago had an existing population of top physicists and chemists, was centrally located far from both coasts, and had space and housing for the project, the nuclear reactor project was headquartered at the University of Chicago and code-named “the Metallurgical Laboratory.”
The Metallurgical Laboratory was led by Prof. Arthur Holly Compton, a Nobel laureate and dean of the physical sciences at UChicago, and included the most eminent physicists, chemists and engineers of the time—including Enrico Fermi, Leo Szilard and Eugene Wigner. Hundreds of people were recruited to “help the war effort,” though most were told very little about the details.
After a series of smaller experiments to prove the concept, work began on the reactor that would actually sustain the chain reaction. It was originally planned to be built west of the city of Chicago, but construction difficulties slowed up progress, so Compton decided they would go ahead and build the reactor where many of the experiments had taken place up to that point—an old squash court underneath the abandoned Stagg Field football stands at the University of Chicago.
It’s debated whether the president of the University of Chicago, Robert Maynard Hutchins, knew the experiment was going to take place, though Compton said he did not tell him. The mayor of Chicago and other elected officials were not notified.