The International Atomic Energy Agency (IAEA) is a United Nations agency responsible for monitoring civil nuclear facilities in non-nuclear weapons states, with the aim of verifying that nuclear materials are not being diverted from these facilities into weapons programs. This worldwide monitoring program is referred to as the IAEA safeguards regime, and is part of the nonproliferation agenda set forth in the global Treaty on the Nonproliferation of Nuclear Weapons (NPT).
The IAEA implements this regime with the help of the NPT member states. Reactor safeguards refers to the part of the program devoted to monitoring the flows of plutonium (and uranium) into and out of nuclear reactors, which are the ultimate source of all the world's plutonium. Reactor safeguards are implemented at about 200 power reactors and at several hundred more research reactors worldwide.

A variety of accounting techniques are currently used by the IAEA to monitor fissile material flows to and from these reactors. Antineutrino detection is a unique supplement to these techniques, since it is the only safeguards method that provides a real-time nonintrusive estimate of the quantity of fissile material in the core while the reactor is operating. For more information on the global safeguards regime, please visit the IAEA web site.