The Pile Under the Squash Court

At 3:25 p.m. on December 2, 1942, in a squash court beneath the west stands of Stagg Field at the University of Chicago, Enrico Fermi directed scientist George Weil to withdraw the final cadmium control rod from a pile of graphite bricks and uranium. The neutron count climbed exponentially and held. For the first time in history, humans had initiated and controlled a nuclear chain reaction. Fermi let it run for 28 minutes, then calmly ordered it shut down.

The reactor, code-named Chicago Pile-1, was crude. Roughly 771,000 pounds of graphite, over 80,000 pounds of uranium oxide and metal, all stacked by hand. No radiation shielding. No backup cooling. The only safety mechanism was control rods and an emergency rope that would drop cadmium panels to kill the reaction. One scientist stood holding a bucket of cadmium solution, ready to pour. They called him the "suicide squad."

The experiment was part of the Manhattan Project. Fermi's pile proved a sustained chain reaction was possible -- a necessary step before designing a weapon. But the same principles would eventually power reactors generating electricity, propelling submarines, and producing medical isotopes.

chicago pile-1 at the university of chicago, 1942. source: wikimedia commons

The success was celebrated quietly. Physicist Eugene Wigner produced a bottle of Chianti. Each scientist drank from paper cups, then signed the straw wrapper. The only message to Washington was coded: "The Italian navigator has landed in the New World." Before that afternoon, nuclear energy was theoretical. After it, the atom was a tool, a weapon, and a responsibility.