Year of Invention: 1942
What Is It? A machine that converts the heat energy of natural nuclear decay
into electrical energy.
Who Invented It? Enrico Fermi (in Chicago)
With Enrico Fermi’s nuclear reactor, the world entered the nuclear age. The nuclear reactor unleashed a vast new source of electrical energy—a source that didn’t depend on limited fossil fuels. More important for science, however, Fermi’s reactor proved the mathematical models scientists used for the structure and action of electrons, neutrons, protons, and the Beta decay process. Finally, nuclear reactors set the stage for the creation of the atomic bomb in 1945.
In 1940, over 90 percent of the world’s electrical supply was produced from fossil fuels. Scientists sought renewable—or inexhaustible—fuel alternatives. Some researchers focused on renewable energy resources (wind, water, and biomass). Some turned to the sun, a virtually inexhaustible energy source. Some turned to the power of the atom.
At 2:20 P.M. on December 2, 1942, Enrico Fermi flipped the switch that raised hundreds of neutron-absorbing cadmium control rods out of his reactor core. Fermi had stacked 42,000 graphite blocks laced with several tons of uranium oxide pellets in an underground squash court situated 20 feet under the west bleachers of Stagg’s field, the University of Chicago football field. No one on campus knew what was happening in that squash court.
Theory said that a nuclear reaction in that water-filled tank would become a controlled and self-sustaining nuclear reactor once the rods were removed. (The cadmium rods absorbed too many neutrons to allow the reaction to develop.) But theories were often wrong. Students 20 feet above hurried past in the bitter-cold winter wind without being aware that their lives depended on the theories and calculations of one man, 35-year-old Enrico Fermi.