Force-on-Force Security Inspections

The Nuclear Regulatory Commission has carried out force-on-force 

inspections regularly at commercial operating nuclear power plants since 

1991 as part of its comprehensive security program. These inspections are 

an important way to evaluate and improve the effectiveness of plant 

security programs under NRC regulations (10 CFR Part 73) to prevent 

radiological sabotage. 

FOF inspections assess a nuclear plant’s physical protection 

measures to defend against the “design basis threat,” or DBT. The DBT 

describes an adversary that plant owners must protect against with physical 

protection systems and response strategies. The NRC periodically 

reassesses the DBT and makes revisions as necessary.

A New, Stronger Force-on-Force Program

Before Sept. 11, 2001, NRC conducted FOF inspections about once every eight years at all 

U.S. commercial nuclear plant sites, in addition to regular baseline security inspections. Following the 

Sept. 11 attacks, the NRC strengthened its FOF program, requiring plants to defend against a tougher 

DBT that reflected the new threat environment and increasing the level of realism.

The NRC’s redesigned FOF program was fully implemented by late 2004. Today, the NRC 

evaluates each plant site every three years. All licensees conduct tactical security exercises in the 

intervening years. (The details of the FOF inspections are Safeguards Information, which is protected 

from public disclosure under the Atomic Energy Act.)

The NRC gives plant operators advance notice of FOF inspections for safety and logistical 

purposes and to provide for coordination of two sets of security officers –– one for maintaining actual 

security, another for participating in the inspection. A key goal is to balance personnel safety, while 

maintaining actual plant security during exercises that are as realistic as possible. 

Inspectors preparing FOF exercises use information from table-top drills, previous inspection 

reports and security plan reviews to design commando-style attacks to probe potential weaknesses in the 

plant’s defenses. The site’s defenders aim to keep the attackers from destroying or damaging key 

equipment. Any potentially significant weaknesses in the protective strategy identified during FOF 

inspections are promptly addressed. FOF inspection teams include active-duty military advisors from the 

U.S. Special Operations Command. They help evaluate site security forces and systems, and provide an 

independent evaluation of the adversary force’s performance.
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Mock Adversary Force

A credible, well-trained, and consistent mock adversary force is 

vital to the FOF program. Prior to Sept. 11, power plant operators used 

a mock adversary force that often included security officers from their 

own sites, other licensees, and state police tactical team members. 

Using these diverse sources caused inconsistencies. The revised FOF 

program uses a mock adversary force specifically trained to NRC 

standards, which cover the skills and physical fitness qualifications of 

team members; team tactics, communications and planning; firearms 

knowledge and proficiency; and exercise simulation equipment. 

To avoid any conflict of interest, the NRC requires a clear 

separation of functions between the mock adversary forces and plant 

security forces. The NRC also maintains control over the design and 

implementation of the FOF inspections.

NRC’s Overall Security Program

FOF inspections are an essential part of NRC’s oversight of plant owners’ security programs and 

their compliance with NRC security requirements. The agency continues to evaluate and strengthen its 

overall security program in response to changes in the threat environment, technological advancements 

and lessons learned. As a result, substantial improvements to nuclear plant security have been made to 

protect against terrorism and radiological sabotage. These include well-trained security forces, robust 

physical barriers, intrusion detection systems, surveillance systems and plant access controls.

Together, these efforts help make nuclear power plants among the best protected private sector

facilities in the nation.

Additional information is available on NRC’s website.

June 2023