Oak Ridge

Oak Ridge: Common Name, Uncommon Purpose

The U.S. government selected the name, Oak Ridge, because it sounded like other communities in East Tennessee. It also was unlikely to draw unnecessary attention to Clinton Engineering Works, the top-secret facilities where scientists and workers created uranium that fueled the world’s first atomic bomb.

On Sept. 19, 1942, Gen. Leslie R. Groves, who was head of the Manhattan Project, selected Oak Ridge as “Site X,” and by November 1942, construction began to accommodate the influx of workers. By August 1945, Oak Ridge, a city not recognized on any map, skyrocketed to a population of 75,000, making it the fifth-largest city in Tennessee.

map rendering of projected site for atomic production plants

Secret Science

For seven years Oak Ridge was a secret city with seven gates preventing public access. Within the secret walls of “Site X,” workers enriched uranium and created the prized isotope known as U-235, which would fuel the world’s first atomic bomb, “Little Boy.” Oak Ridge’s operations included three different processes for enrichment: electromagnetic separation at the Y-12 plant, gaseous diffusion at the K-25 plant, and liquid thermal diffusion at the S-50 plant.

Oak Ridge was also home to the X-10 graphite reactor, which used neutrons in the fission of U-235 to convert the heavier isotope U-238 into a new element, plutonium. Hanford, Wa. continued this process on a larger scale at its facilities.

Oak Ridge by the Numbers

With 850 buses, Oak Ridge had the ninth largest bus system in the nation. At one point, the city consumed a seventh of all the electricity produced by the Tennessee Valley Authority, 20 percent more than the amount needed to power all of New York City. One of Oak Ridge’s uranium-enriching facilities, the K-25 plant, covered 44 acres, making it the largest building in the world at the time.

black and white photo of military district


After the war ended, the government formed Oak Ridge National Laboratory in March 1948, devoting the city’s wartime technologies to new purposes.

  • X-10 facilitated work on medical isotopes and nuclear power.
  • Y-12 became the nation’s uranium production facility and continues to maintain the nuclear portion of the thermonuclear weapons for the U.S. military.
  • K-25 provided highly enriched uranium for the nation’s nuclear weapons and fuel for nuclear power reactors around the world.

Today Oak Ridge is a thriving city of 30,000, home to two of the top 10 largest employers in Tennessee, the world’s most powerful pulse neutron source, and the second most powerful supercomputer.