Protection and Security of Radiation Sources

Keeping radioactive materials out of the hands of terrorists is a top priority for the Nuclear 

Regulatory Commission. The NRC and its Agreement States1 have in place a multi-layered, 

comprehensive security program to protect these sources. This program has been effective, keeping 

incidents to a minimum and their consequences low. Most lost or stolen sources are quickly found, with 

little or no radiation exposure or contamination. The NRC continues to work at home and abroad to 

make risk-significant radiation sources2 even more secure. The United States was the first country to 

require enhanced security measures for radioactive sources, and the NRC continues to lead the world in 

source security.

Benefits of Sources

A “source” is a piece of radioactive material produced in a nuclear reactor. Sources are isotopes 

such as cobalt-60, iodine-131, cesium-137 or americium-141. The radiation they emit is useful in a 

variety of ways in industry, medicine and research. For example:

• Gauges measure the moisture in soil during construction of roads and buildings, or the flow of 

liquids through pipes.

• Radiography cameras detect structural flaws in buildings or pipe welds.

• Irradiators sterilize medical equipment and blood, or eliminate pests from food.

• Well-logging devices help map oil and natural gas deposits.

• Isotopes used in medicine can detect or treat thyroid issues and cancer, such as brain tumors.

Strong Security Requirements

At first, the security requirements for sources focused on avoiding unintended radiation 

exposures to workers or the public. Today, they aim to keep sources out of the hands of terrorists. These 

security measures suit the facilities where sources are stored and the level of risk they pose. They have 

multiple layers, a flexible framework and reflect the NRC’s strong commitment to ensuring the security 

and control of sources. 

 

1 The NRC has signed agreements with many states, under which the NRC relinquishes authority to license and regulate radioactive 

materials used in industry, medicine and research.

2 The NRC defines “risk-significant sources” as those listed in Category 1 and Category 2 of the International Atomic Energy 

Agency’s “Code of Conduct on the Safety and Security of Radioactive Sources.”
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Key elements of the program include:

• Background checks, including fingerprinting, to ensure that people with access to sources are 

trustworthy and reliable.

• Physical barriers and personnel access controls to areas where sources are stored or used.

• Security plans and procedures to detect, deter, assess and respond to unauthorized access 

attempts.

• Coordination and response planning between licensees and local law enforcement agencies.

• Coordination and tracking of shipments of radioactive material.

• Security barriers to discourage theft of portable devices containing radioactive material.

The NRC and the Agreement States regularly inspect licensees to ensure their security programs 

meet these requirements and the materials remain secure. While there have been no specific, credible 

threats against radioactive sources, the NRC remains vigilant. Agency security experts coordinate with 

other federal agencies and the intelligence community to counter any threat that may arise.

Many of these requirements were spelled out in Orders the NRC and the states began to issue in 

2005. The NRC incorporated them into a final rule, 10 CFR Part 37, “Physical Protection of Byproduct 

Material,” published in March 2013. The rule includes lessons learned from implementing the orders, 

plus new requirements for things such as training for staff and notifying the NRC.

Managing Source Information

The National Source Tracking 

System is a secure database that tracks 

the most risk-significant sources from 

manufacture or import through 

disposal or export. Licensees enter the 

receipt, transfer or disposal of sources 

into the database, so the NRC knows 

where the sources are. This 

information also helps the NRC 

respond during natural disasters such 

as floods or hurricanes.

The NRC has also put in place 

a Web-Based Licensing system and a 

License Verification System. The three 

systems work together to provide 

federal and state officials with 

information on about 1,400 NRC and Agreement State licensees and the more than 77,000 risksignificant sources they possess. They make information available to other federal and state agencies 

with a role in protecting the nation from nuclear and radiological threats. They track all those authorized 
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to possess sources, allow licensees to verify that information before transferring sources, and help alert 

regulators to any discrepancies in source inventories.

Partnership with Other Agencies

The NRC and Agreement States regularly inspect materials licensees to ensure they are meeting 

safety and security requirements. The Department of Energy’s National Nuclear Security Administration 

retrieves and disposes of unused or abandoned sources. NNSA and NRC also work with licensees to 

promote voluntary enhancements to the NRC’s already robust security requirements so that the most 

risk-significant sources remain secure and available to perform their beneficial roles for society.

May 2019