Two trainees in personal protective equipment train approach a building structure.

Counter Terrorism Operations Support (CTOS) Center for Radiological/Nuclear Training

Two trainees in personal protective equipment train approach a building structure.

Counter Terrorism Operations Support (CTOS) Center for Radiological/Nuclear Training

The NNSS Counter Terrorism Operations Support (CTOS) program’s mission is to develop and deliver the most realistic and highest quality training in support of homeland security using extensive radiological expertise with the unique assets of the NNSS.

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The nation’s premier radiological/nuclear weapons of mass destruction (WMD) counterterrorism training center, the NNSA CTOS–Center for Radiological/Nuclear Training at NNSS has trained America’s first responders since 1998. CTOS represents the NNSA’s Nevada Field Office as a charter member of the National Domestic Preparedness Consortium (NDPC). The mission of the NDPC is to enhance the preparedness of federal, state, local, and tribal emergency responders/first receivers and teams, including non-governmental organizations and the private sector, to reduce the nation’s vulnerability to incidents involving WMD, terrorism, and all-hazard, high-consequence events by providing technical assistance and developing, delivering, and assessing plans, training, and exercises. The NDPC operates under the oversight of the Department of Homeland Security, Federal Emergency Management Agency’s National Preparedness Directorate National Training and Education Division. Over the years, CTOS has substantially contributed to national preparedness, training responders from all 50 states and each U.S. territory. Since September 11, 2001, nearly 300,000 first responders have been trained through various methods of delivery. Today, CTOS delivers training and education needs of more than 20,000 emergency responders in state, local, and tribal governments each year.


The NNSS CTOS program develops and delivers training for emergency responders to take immediate, decisive action to prevent or respond to terrorist use of radiological or nuclear WMD, such as radiological dispersal devices and improvised nuclear devices. Training and course materials are provided at no cost to eligible participants. Courses are conducted at NNSS, municipality-hosted locations, and online. For a list of all mobile, resident, and online courses, visit the CTOS website at

Nevada National Security Site 

The NNSS is a large, outdoor laboratory, national experimental center, and training facility located 65 miles northwest of Las Vegas, Nevada. Originally established for testing nuclear weapons, from 1951 to 1992, NNSS was the location of 928 nuclear tests and numerous radiological dispersal tests. Since the 1950s, NNSS has been conducting training and exercises using radioactive materials and contaminated environments. Today, the 1,355 square miles of secluded and secure land at NNSS provides a safe environment for training in realistic WMD scenarios.

Two trainees in personal protective equipment enter a training facility using radiological detection equipment.
Participants use radiation detection equipment during a training exercise at the NNSS’ Phoenix location.

Actual Radioactive Material

CTOS courses, except for the awareness-level and online courses, are performance-based using multiple types of radioactive material, most of which use special nuclear materials, such as uranium and plutonium. Courses are designed so participants receive only minor radiation doses—lower than a chest X-ray or a typical round-trip airline flight across the United States. The radiation levels are sufficient to learn techniques required in an actual incident involving much higher radiation levels. Each participant operates and employs radiation detection and measurement instruments throughout the course. Participants train with radioactive material in classroom practice, scenario-based drills, and performance evaluations.