Oak Ridge, a small city west of Knoxville, was the site of Oak Ridge National Laboratory, which produced plutonium and enriched uranium for the Manhattan Project of World War II.
Oak Ridge site - Manhattan Project National Historical Park
"Oak Ridge" / Charles W. Johnson, Tennessee Encyclopedia
American Museum of Science and Energy (AMSE)
"The convoluted story of how the first atoms of Tennessine were created" (NPR)