Dr. Enrico Fermi achieves the first controlled nuclear chain reaction with the first demonstration reactor—the Chicago Pile 1.
The U.S. drops an atomic bomb on Hiroshima, Japan, and three days later drops another bomb on Nagasaki. World War II ends days later.
President Harry S. Truman signs the Atomic Energy Act of 1946, putting the fledgling nuclear energy industry under civilian control, and creating the powerful Joint Congressional Committee on Atomic Energy.
The U.S. Atomic Energy Commission first investigates the possibility of peaceful uses of atomic energy, issuing a report the following year.
An experimental reactor produces the first electric power from the atom, lighting four lightbulbs.
Keel for the Navy's first nuclear submarine, Nautilus, laid at Groton, Connecticut.
Nautilus first starts its nuclear power units.
President Dwight D. Eisenhower unveils his "Atoms-for-Peace" program, proposing an international agency to develop peaceful nuclear technologies.
President Eisenhower signs the Atomic Energy Act of 1954, the first major amendment of the original Atomic Energy Act, giving the civilian nuclear energy program further access to nuclear technology.
The Atomic Energy Commission announces the beginning of a cooperative program between government and industry to develop nuclear power plants.