Book excerpt: The physical security of nuclear power plants (NPP) and their vulnerability to acts of terrorism was elevated to a national security concern following the 9/11 attacks. Since then, Congress has focused oversight and legislative attention on NPP security requirements. The Energy Policy Act of 2005 act required NRC to conduct ¿force-on-force¿ security exercises at NPP at least once every 3 years. In these exercises, a mock adversary force from outside a NPP attempts to penetrate the plant¿s vital area and simulate damage to key safety components. Contents of this report: Overview of Reactor Security; Design Basis Threat; Large Aircraft Crashes; Force-On-Force Exercises; Emergency Response; Spent Fuel Storage; and Security Personnel.