Energy Reorganization Act
Under the "Atomic Energy Act of 1954" a single agency, the Atomic Energy Commission had responsibility for the development and production of nuclear weapons and for the development and safety regulation of the civilian uses of nuclear materials.
The "Energy Reorganization Act of 1974" split those functions. The Energy Research and Development Administration, which became the Department of Energy in 1977, was given the responsibility for the development and production of nuclear weapons, promotion of nuclear power, and other energy-related work. The Nuclear Regulatory Commission was given the regulatory and licensing functions.