U.S. Department of Energy

The Three Mile Island Unit 1 reactor has an electrical capacity of 835 megawatts, which the U.S. Department of Energy has described as approximately equivalent to powering 800,000 homes.

The combined nuclear modernization and sustainment plans for 2025–2034 of the U.S. Department of Defense and the U.S. Department of Energy total $946 billion, according to the Congressional Budget Office.

The National Nuclear Security Administration (NNSA) is an agency within the U.S. Department of Energy that maintains the United States' nuclear weapons stockpile and works to reduce the threat of nuclear weapons in foreign nations.

The National Nuclear Security Administration (NNSA) is a component of the U.S. Department of Energy whose core mission includes ensuring the United States maintains a safe, secure, and reliable nuclear stockpile through the application of science, technology, engineering, and manufacturing.

Several federal buildings in Washington, D.C. serve as agency headquarters: the Frances Perkins Federal Building (U.S. Department of Labor), the James V. Forrestal Building (U.S. Department of Energy), the Theodore Roosevelt Federal Building (U.S. Office of Personnel Management), the Robert C. Weaver Federal Building (U.S. Department of Housing and Urban Development), the Department of Agriculture South Building (U.S. Department of Agriculture), and the Hubert H. Humphrey Federal Building (U.S. Department of Health and Human Services).

The U.S. Department of Energy operates 17 national laboratories.