|Fig. 1: The Watt Nuclear Power Plant located in Tennessee. (Source: Wikimedia Commons)|
Nuclear power plants (Fig. 1) are arguably the most high value targets for terrorist attack in the United States, but also some of the best protected. With 104 commercial nuclear reactors operating around the country, there are many bases to cover for the Nuclear Regulatory Commission, and each power plant presents its own unique defense challenges.  Following the events on September 11th, 2001 and a review of nuclear power plant security, the NRC ordered all plants to enhance their defense capabilities in order to ensure the safety of nuclear materials as well as civilians living near the plants. While many of the exact security details are kept classified for obvious reasons, a general overview of nuclear power plant defense plans, as well as upgrades made since 2001, is available to the public.
The main defense of all US nuclear reactors is the 11-foot-thick structures enclosing them. While not all identical, each structure is designed to withstand the impact of a small bomb or even plane crash. In 1988, Sandia National Laboratories in New Mexico conducted a test that involved crashing A fighter jet into a nuclear enclosure. Specific details regarding the results of the test and composition of the structure are unavailable for security reasons, but unofficial accounts say that the plane disintegrated, and only penetrated a few inches into the structure.
Outside of the enclosure, standard high-level security measures are implemented on a plant-by-plant basis. Each plant has its own specific response to emergency events like a fire, loss of power, or natural disaster based on its layout and geographic location. Common physical defenses include access checkpoints, security cameras, guard towers, armed roving security details, and barbed fences and barriers, all designed to keep out any intruders.  In the past 15 years, the NRC has also enforced a heightened awareness of those working inside the plants, as the commission has made background checks of even the most tenured employees more robust in the hopes of preventing an internal sabotage of any plant. 9,000 highly trained security personnel have been educated and deployed to plants across the country since 9/11. 
Because an actual terrorist attack on a nuclear power plant has not yet been carried out, the NRC also works with US Special Operations Forces to conduct force-on-force exercises at many plants. During these exercises, trained operatives will plan and carry out varying attacks on US nuclear plants in order to try and expose any security vulnerabilities.  This has helped the NRC identify and eliminate potential weaknesses, even in the absence of a real attack.
|Fig. 2: A commercial drone. (Source: Wikimedia Commons)|
Even with many physical defense measures in place, nuclear power plants still have vulnerability to non-human attack. As Stuxnet proved in Iran, non-human threats are real and dangerous, as the virus was able to destroy over ten percent of the country's nuclear centrifuges.  Because of this, the NRC established their own internal Cyber Security Directorate (CSD) in 2013 to oversee every nuclear plant's cyber defense capabilities and assess real-world threats to prevent the compromise of computer systems at the plants. 
Another recent potential threat to nuclear plants is commercial drones (Fig. 2), which have been spotted flying over several plants in France.  While these drones have so far been harmless, it is unclear whether pranksters or potential attackers looking to scope out facilities are controlling the drones. Some experts are concerned that nuclear power plants are not safe from a simple attack, and that a commercial unmanned drone with a small payload could cause a meltdown. 
This issue has come to light just recently and a response to drone threats is unclear. In-depth information regarding the drones spotted in France has not been released. The world of terrorist threats is constantly evolving, and the NRC is trying to stay ahead of potential attackers on all fronts.
© Austin Barr. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
 T. Gardner, "US Nuclear Power Plants Vulnerable to 9/11 Style Attacks: Report," Reuters, 15 Aug 13.
 "Protecting Our Nation," U.S. Nuclear Regulatory Commission, NUREG/BR-0314, October 2013.
 J. Warrick, "Iran's Natanz Nuclear Facility Recovered Quickly from Stuxnet Cyberattack," Washington Post, 16 Feb 11.
 C. Phillips and C. Gaffey, "Most French Plants 'Should Be Shut Down' Over Drone Threat", Newsweek, 24 Feb 15.