Defense in depth (nuclear engineering)

U.S. non-military nuclear material is regulated by the U.S. Nuclear Regulatory Commission, which uses the concept of defense in depth when protecting the health and safety of the public from the hazards associated with nuclear materials. The NRC defines defense in depth as creating multiple independent and redundant layers of protection and response to failures, accidents, or fires in power plants.

Source: Wikipedia — Defense in depth (nuclear engineering) (CC BY-SA 4.0)