"The physical security of nuclear power plants and their vulnerability to deliberate acts of terrorism was elevated to a national security concern following the events of September 11, 2001. Title VI of the Energy Policy Act of 2005 regarding nuclear security amended the Atomic Energy Act with the addition of new provisions for security evaluations and rulemaking to revise the 'Design Basis Threat.' The act included provisions for fingerprinting and criminal background checks of security personnel, their use of firearms, and the unauthorized introduction of dangerous weapons. The designation of facilities subject to enforcement of penalties for sabotage expanded to include treatment and disposal facilities. As part of security response evaluations, the act requires the Nuclear Regulatory Commission (NRC) to conduct 'force-on-force' security exercises at nuclear power plants at least once every three years, and revise the 'design-basis threat' to consider a wider variety of potential attacks. The NRC has strengthened its regulations on nuclear power plant security, but critics contend that implementation by the industry has been too slow and that further measures are needed. Vulnerability to a deliberate aircraft crash remains an outstanding issue, as the latest NRC rulemaking addresses only newly designed plants. Shortcomings in the performance of security contractors has drawn the attention of Congress."
CRS Report for Congress, RL34331