Naval Reactors (NR), also known as the Naval Nuclear Propulsion Program, is an umbrella term for the U.S. government office that has comprehensive responsibility for the safe and reliable operation of the United States Navy's nuclear propulsion program. A single entity, it has authority and reporting responsibilities within both the United States Department of the Navy (Office of the Chief of Naval Operations, OPNAV, and the Naval Sea Systems Command, NAVSEA) and the United States Department of Energy in its National Nuclear Security Administration.