United States Nuclear Regulatory Commission - Protecting People and the Environment

Frequently Asked Questions About NRC's Response to the 9/11/01 Events

This page contains frequently asked questions and answers on the NRC's accomplishments since September 11, 2001, that have made nuclear power plants and other NRC licensed activities more secure. The list below is alphabetized to easily access information. Where possible, links are provided for those wishing more information on a particular subject.

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Index to All Frequently Asked Questions Pages

Advisories and Orders

What are Advisories, Orders, and Interim Compensatory Measures?

Advisories are non-public, rapid communications from NRC to its licensees that provide information obtained from the intelligence community or law enforcement agencies on changes to the threat environment and guidance for licensees to take specific actions promptly to strengthen their capability against the threat. Although Advisories are not legally binding, they are effective in quickly conveying important information to large numbers of licensees. They are tailored to categories of licensees including power reactors, non-power reactors, fuel facilities, decommissioning reactors, independent spent fuel storage installations, gaseous diffusion plants, and materials licensees.

Orders are regulatory requirements that may modify, suspend, or revoke a license or require specific actions by the licensee. Orders issued after September 11, 2001, modified the operating license for each facility that will remain in effect until the Commission determines that the level of threat has diminished or that modifications to the Orders are appropriate.

Interim Compensatory Measures (ICMs) that were included with the Orders issued after September 11, 2001, to enhance security are considered sensitive information and are not available to the public. Orders were chosen to direct licensees to take immediate action while more deliberate vulnerability studies are completed that will determine further action. ICMs delineate specific licensee responsibilities outlined in the Order.

What Advisories and Orders has NRC issued since September 11, 2001?

Immediately following the attacks of September 11, 2001, NRC issued a series of Advisories to its major licensed facilities. These advised licensees to go to the highest level of security, in accordance with the system that was in place at the time, that they promptly did. The NRC has issued numerous Advisories to licensees in response to the events of September 11, 2001, that told licensees to take a number of additional measures to further augment security. Some of the specific measures implemented by the licensees in response to the Advisories included increased patrols, augmented security forces and capabilities, additional security posts, installation of additional physical barriers, vehicle checks at greater stand-off distances, enhanced coordination with law enforcement and military authorities, and more restrictive site access controls. The security of the nuclear industry has been significantly enhanced as a result of the voluntary actions licensees took following the attacks on September 11, 2001.

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Orders Issued

Since September 11, 2001, NRC has issued Orders to its major licensees. These Orders include measures to protect against an insider terrorist attack; waterborne, airborne, and land-based assaults; as well as threats from a vehicle bomb. The specific security measures generally include increased patrols, augmented security forces and capabilities, additional security posts, installation of additional physical barriers, vehicle checks at greater stand-off distances, enhanced coordination with law enforcement and military authorities, and more restrictive site access controls. NRC evaluates implementation of the Orders through onsite inspections following receipt of the mandatory compliance data. In addition, NRC issued Orders on access authorization on January 7, 2003, and on fatigue, guard training and qualification, and the revised design basis threat on April 29, 2003.

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Aircraft Attack

What is the NRC doing to protect nuclear facilities from an aircraft attack?

The Commission believes that the best approach to dealing with threats from aircraft is through strengthening airport and airline security measures. Consequently, we continue to work closely with the appropriate Federal agencies to enhance aviation security and thereby the security of nuclear power plants and other NRC-licensed facilities. Shortly after the September 11, 2001 attacks, NRC, working with representatives of the Federal Aviation Administration (FAA) and Department of Defense (DOD), determined that a Notice to Airmen (NOTAM), issued by the FAA, was the appropriate vehicle to protect the airspace above sensitive sites. This NOTAM strongly urged pilots to not circle or loiter over the following sites: nuclear/electrical power plants, power distribution stations, dams, reservoirs, refineries, or military installations or they can expect to be interviewed by law enforcement personnel.

Why doesn't the NRC install anti-aircraft weapons at nuclear power plants to protect them against an airborne terrorist attack?

The deployment of anti-aircraft weapons would be a decision for the Secretary of Defense, not the NRC. However, NRC believes that application of anti-aircraft weapons would present significant command and control challenges, particularly relating to the time required to identify a hostile aircraft and get permission to shoot down a civilian commercial aircraft and the potential for collateral damage to the surrounding community. Additional information on this subject can be found in the testimony provided by former Chairman Meserve to the U.S. House of Representatives on April 11, 2002, and to the U.S. Senate on June 5, 2002.

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Decommissioning Power Reactors

What steps has the NRC taken at nuclear power plants being decommissioned since September 11, 2001, to ensure that a terrorist attack on the spent fuel pool does not result in a fire and/or large release of radioactive materials?

Before September 11, 2001, the NRC established guidelines for increased security measures at these facilities. Following the events of September 11, 2001, each decommissioning reactor facility committed to take certain actions to enhance security and to protect against a variety of threats. NRC then ordered that additional security enhancements be implemented for spent fuel pools and decommissioning reactors. Further, the NRC issued a Regulatory Issue Summary (a vehicle for communicating significant regulatory information to licensees) for decommissioning reactors that transmitted the NRC Threat Advisory System to describe protective measures to be taken to deal with changes in the threat environment.

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Design Basis Threat

What is a "design basis threat"?

The design basis threat (DBT) describes the approximate size and attributes of the threat that licensees must defend their facilities against. NRC has two distinct DBTs: theft of nuclear material and radiological sabotage. These DBTs are described generally in 10 CFR 73.1. The details of the DBT are considered sensitive and are not publicly available.

Has the NRC considered any changes in the design basis threat as a result of the terrorist attacks of September 11, 2001?

The NRC continually examines the assumptions underlying the DBT and the DBT itself. On April 29, 2003, the NRC issued Orders to power reactor and certain fuel fabrication licensees to implement a revised DBT by October 2004. Under NRC regulations, these licensees must ensure that the physical protection plan for each site is designed and implemented to provide high assurance in defending against the DBT to ensure adequate protection of public health and safety and common defense and security. The details of the revised DBTs are sensitive security information and cannot be released to the public. Additional information on this subject can be found in the testimony provided by Chairman Meserve to the U.S. House of Representatives on April 11, 2002.

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Dirty Bombs

What is a "dirty bomb"?

A "dirty bomb" or radiological dispersal device (RDD) is a conventional explosive containing radioactive material. A conventional explosive can be used to spread radioactive contamination. It is not a nuclear bomb and does not produce a nuclear explosion.

What would be the danger to the public if terrorists were successful in acquiring radioactive material and detonating a dirty bomb?

The radioactive material could contaminate a large area, a few city blocks or more, depending on the type and amount of radioactive material used, amount and type of explosive, weather conditions, and other factors. It is unlikely that significant immediate health effects or prompt fatalities would result, other than from the explosion itself, because people would run away from the explosion and the radioactive material would disperse, reducing the potential for high radiation exposure. Over the long term, people who were contaminated or exposed to elevated radiation levels may have an increased risk of cancer.

How would officials respond to a dirty bomb attack?

Officials would restrict public access to the contaminated area, call in experts to assess the degree of radioactive contamination, and decontaminate the area. People in the vicinity of the explosion would be checked for contamination, decontaminated if necessary, and receive follow-up medical attention if needed.

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Emergency Preparedness

What does the NRC require of reactor and fuel facility licensees for emergency preparedness?

The NRC requires licensees to have detailed procedures for responding to events, making timely notifications to appropriate authorities, and providing accurate radiological information. These licensees are required to exercise their programs on a periodic basis and to coordinate their planned actions with Federal, State, and local officials.

Have changes been made in the licensees' emergency preparedness programs since September 11, 2001?

The NRC issued Orders to its licensees requiring that emergency plans be reviewed and revised, as necessary, to ensure they are compatible with the heightened security posture that exists at each plant.

What Federal agencies are responsible for emergency preparedness programs at nuclear facilities?

The NRC and the Federal Emergency Management Agency (FEMA) are the two Federal agencies responsible for evaluating emergency preparedness programs at and around nuclear power plants. The NRC is responsible for evaluating the adequacy of onsite emergency plans and capabilities developed by the utility, while FEMA is responsible for assessing the adequacy of offsite (State and local) radiological emergency planning and preparedness activities.

Does the NRC work with the Federal Emergency Management Agency (FEMA) in reviewing emergency programs at nuclear facilities?

Yes. The NRC and FEMA both have responsibilities relating to review of the emergency plans at nuclear facilities. The NRC is primarily responsible for onsite preparedness, and FEMA is primarily responsible for offsite planning. Exercises run by the licensees to test their preparedness are observed and evaluated by both NRC and FEMA.

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Federalization of Security Forces

What is the NRC's position on whether security forces around nuclear power plants should be Federal employees?

NRC has given this matter careful consideration and ultimately opposes federalization because it would not serve the national interest. There would be serious command and control problems if security were placed under Federal management, while at the same time safety remained the responsibility of the private operator. The NRC believes that these functions must be integrated. In addition, the Federal government would have to provide funding for security forces. The private sector security forces that exist today at nuclear facilities are qualified, trained, compensated, and tightly regulated. The NRC also does not recommend providing full-time permanent military protection at nuclear power plant sites. (See testimony.)

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Interagency Coordination

Where does the NRC get its information concerning threats to nuclear facilities?

The NRC receives a substantial and steady flow of information from the national intelligence community, law enforcement, and licensees. NRC promptly evaluates this information to assess threats to regulated facilities or activities. The NRC has received assistance from across the government regarding protection of nuclear power plants and related activities.

What other agencies of the Federal government does NRC work with to ensure nuclear power plant security?

The NRC works with a variety of other Federal agencies, in particular the Department of Homeland Security and Homeland Security Advisory Council, to ensure that security around nuclear power plants is well coordinated and that responders are prepared if a significant event occurs. If an event were to occur, the NRC would coordinate the resources of more than 18 Federal agencies in response to radiological aspects.

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How well protected are the irradiators against possible attack, theft, or sabotage?

Irradiators have typical industrial security measures (locked barriers, alarms, and access control) intended to prevent unauthorized access and routine theft.

Have protective measures for irradiators been enhanced since 9/11/01?

Following 9/11/01, NRC and Agreement States issued Advisories to licensees, including irradiator operators, recommending that they increase security and be alert to any unusual activities that might indicate a terrorist threat. On June 13, 2003, NRC issued Orders to licensees of all panoramic and underwater irradiators to implement security enhancement.

What special equipment would be needed to transport cobalt-60 or other radioactive material from an irradiator if its defenses were overcome? What other radioactive sources are contained in such irradiators?

Heavy shielding and remote handling tools, weighing hundreds to thousands of pounds, would be needed to move radioactive sources from irradiators. There are no other significant radiation sources at irradiators.

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Has the NRC proposed any legislation that would improve security at nuclear facilities?

The NRC provided legislative proposals to Congress detailing specific initiatives that would further enhance security of NRC-licensed activities by amending the Atomic Energy Act. To date, these proposals include

  • authorizing armed guards to use deadly force in the protection of the facility;
  • authorizing armed guards at nuclear plants to carry weapons that are comparable with those used by the Department of Energy's guard forces;
  • criminalizing the carrying of unauthorized weapons and explosives into NRC-licensed facilities;
  • making Federal prohibitions on sabotage applicable to the operation and construction of certain nuclear facilities;
  • expanding categories of persons subject to fingerprinting; and
  • providing NRC broader regulatory authority over radioactive material.

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NRC's Actions Immediately Following the Events of 9/11/01

What actions did the NRC take immediately following the terrorist events?

Promptly after the terrorist events on September 11, 2001, the NRC activated its Incident Response Center at NRC Headquarters and in the regional offices, staffed the centers with teams of top officials and technical experts, and maintained this staffing for several months. The NRC advised its licensees to go to the highest level of security and the agency established communications with the FBI, the Department of Energy, and the Federal Emergency Management Agency, among others. For more information, see the NRC Press Release issued on September 21, 2001.

What additional steps did the NRC take to ensure the security of nuclear power plants and fuel facilities?

The NRC has issued more than 60 Advisories to its licensees to describe changes in the threat environment and provide guidance on ways to enhance security. Also, NRC issued Orders requiring certain security enhancements, conducted a three-phase audit of the licensees' security programs in the weeks following the terrorist attacks, improved the process for conducting background investigations of new employees at nuclear power plants, and initiated a number of studies related to the protection of nuclear material and facilities.

The NRC initiated, and is continuing, a comprehensive reevaluation of the agency's safeguards and security programs, including a review of the design basis threat, and consolidated the security and emergency response functions of the agency into a new Office of Nuclear Security and Incident Response. The agency has enhanced the security of its own buildings to protect the employees and vital functions and installed secure communications equipment at significant licensee facilities to facilitate rapid transmission of classified information relating to potential threats. The NRC also removed the agency Web site from the Internet soon after September 11, 2001, to review information for sensitivity to potential use by terrorists. The restructured Web site was restored one week later.

What were some of the long-term actions taken by the NRC?

In the months following the terrorist attacks of September 11, 2001, the NRC issued Orders to nuclear power reactors, decommissioning reactors, gaseous diffusion plants, the uranium conversion facility, fuel fabrication facilities, and panoramic irradiator license requiring them to implement enhanced security measures designed to protect against an increased threat. Additional information on this subject can be found in the testimony provided by former Chairman Meserve to the U.S. Senate on June 5, 2002. The NRC also initiated a number of studies on the effects of a large commercial aircraft hitting a nuclear power plant. Those studies are ongoing.

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Potassium Iodide (KI)

What is potassium iodide?

Potassium iodide is a salt, similar to table salt. Its chemical symbol is KI. With the appropriate dosage, KI blocks the thyroid gland's uptake of radioactive iodine and thus could reduce the risk of thyroid cancers and other diseases that might otherwise be caused by exposure to radioactive iodine that could be dispersed in a severe nuclear accident. KI is not effective against radiation contamination from a "dirty bomb" since radioactive iodine is not present.

Is the NRC taking steps to distribute potassium iodide (KI) to the people around nuclear power plants?

In coordination with FEMA and the Food and Drug Administration (FDA), the NRC has established a policy with respect to KI distribution within the 10-mile emergency planning zone of each nuclear power plant. The agency is currently shipping KI tablets at Federal expense to States that have requested KI as part of their emergency response plans. NRC coordinates closely with FEMA, FDA, and the States with respect to this issue.

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Public Information and Confidence

What has NRC done to enhance public confidence since September 11, 2001?

NRC strives to conduct as much of its work as possible in an open arena. In particular, we have sought to understand the concerns of citizens and State and local officials, for example, by conducting a large number of open meetings. However, immediately following September 11, 2001, we temporarily modified our approach due to security concerns. Although many security concerns persist, the NRC has resumed meetings open to the public, except for meetings on security subjects that include sensitive information, and the NRC has also revised and enhanced its public Web site. NRC continues to inspect security at NRC-licensed facilities and has stepped up and expanded involvement with the Federal Bureau of Investigation, the Department of Homeland Security and other intelligence and law enforcement agencies, NRC licensees, and military, State, and local authorities. Our Web site provides citizens with extensive information about our activities. If you would like to send us your comments or questions please contact us.

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Radioactive Sources

What is the NRC doing to prevent a terrorist from using radioactive sources in a terrorist attack?

The NRC is currently reviewing aspects of its security recruitment for control of radioactive sources. This review may result in additional recommendations for increasing security and control to protect radioactive materials from a terrorist threat or other malevolent uses. NRC is also coordinating with the Department of Energy (DOE) to accelerate the DOE program to retrieve unused and/or unwanted radioactive sources from NRC and Agreement State licensees.

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Security at Nuclear Facilities Since 9/11/01

How has security been enhanced at nuclear facilities since September 11, 2001?

The NRC placed the 103 operating nuclear power plants and other significant licensees on the highest level of alert immediately after the September 11, 2001 attacks and has overseen the implementation of enhanced security measures over the last year. Licensees throughout the nuclear industry have significantly enhanced security by upgrading security measures and coordinating with local, State, and Federal agencies to better prepare for a significant terrorist event.

Some of the specific measures implemented by the licensees in response to the NRC Advisories and Orders included increased patrols, augmented security forces and capabilities, additional security posts, installation of additional physical barriers, vehicle checks at greater stand-off distances, enhanced coordination with law enforcement and military authorities, and more restrictive site access controls for all personnel. Additional information on this subject can be found in the testimony provided by former Chairman Meserve to the U.S. House of Representatives on April 11, 2002.

Are nuclear power plants today capable of withstanding a 9/11-scale attack -- or even the smaller attacks anticipated before 9/11/01?

Before September 11, 2001, the security measures in place provided reasonable assurance that the health and safety of the public would be protected in the event of an attack within the design basis threat (DBT) of radiological sabotage in 10 CFR 73.1. Since September 11, 2001, the defensive capability of the industry has been significantly enhanced as a result of the actions taken by licensees voluntarily and in response to the Advisories issued by the NRC after September 11, 2001, and the Orders issued on February 25, 2002. In addition, on April 29, 2003, NRC issued a revised DBT against that licensees must be prepared to defend. The enhancements include security measures against an insider, waterborne attacks, vehicle bombs, and land-based assault threats. Additional measures will be considered in the future as necessary.

What Federal agencies are responsible for security at nuclear power plants and what are the roles of each agency?

The NRC is responsible for assuring protection of the public health and safety in the civilian use of nuclear material. This includes ensuring that commercial nuclear power plant licensees provide a program of physical protection in accordance with the requirements in Title 10 of the Code of Federal Regulations, Section 73.55.

Were the U.S. Coast Guard and National Guard assigned to protect nuclear power plants in the aftermath of September 11, 2001?

The NRC has been in close coordination with many Federal agencies, including the U.S. Coast Guard, to provide added security around the nuclear facilities, such as the waterways at the plants' intake structures. Various units of the U.S. Coast Guard and the National Guard were assigned by State officials to augment security at nuclear power plants.

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Spent Fuel Storage

How is spent nuclear fuel stored?

Spent nuclear fuel is stored at nuclear plant sites and in spent fuel pools or in dry storage casks. Spent fuel pools use water to cool the radioactive material and shield workers from radiation. Pools are robust structures constructed of very thick reinforced concrete walls with stainless steel liners. They are constructed to withstand earthquakes and other natural phenomena and accidents.

What is a dry storage cask?

Dry storage casks use inert gas inside a heavy steel and concrete container. Casks provide a leak-tight containment for the spent fuel and provide radiation shielding to workers and members of the public.

What would happen to spent fuel in storage if it were subjected to terrorist attack?

The NRC considers spent fuel storage facilities to be robust so that in the event of a terrorist attack similar to those of September 11, 2001, no negative effect on the storage of radioactive materials would result. Spent fuel pools and dry storage casks do not have flammable material to fuel long-duration fires, unlike the structures that were destroyed on September 11, 2001.

The NRC is conducting a comprehensive evaluation that includes consideration of potential consequences of terrorist attacks using various explosives or other techniques on spent fuel pools and dry storage casks. As part of this reevaluation, the agency will consider the need for additional requirements to enhance licensee security and public safety.

What is the danger from radioactive contamination as a result of a terrorist attack?

It is very unlikely that any substantial radiological release would occur from an attack on a spent fuel pool or dry cask storage facility. However, as indicated above, the NRC is reevaluating the need for additional requirements to enhance spent fuel security. Assessing the precise amount of contamination resulting from a release depends on many factors such as type and amount of damage to the pool, location of the damage, proximity of the storage facility to populated areas, and meteorological conditions at the time of the event. If an attack were to occur, licensees have approved emergency plans that are tested biennially involving coordination with local, State, and Federal governments. NRC believes that the health and safety of the public are well protected.

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Spent Fuel Transportation

How would the transportation of radioactive materials be affected by a terrorist attack?

Most shipments of radioactive materials involve mildly radioactive material such as pharmaceuticals, ores, low-level radioactive waste, and consumer products containing radionuclides (e.g., watches, smoke detectors). A variety of Federal and State government agencies regulate the shipment of radioactive material.

High-level nuclear waste materials, such as spent nuclear fuel, are transported in very heavy, robust containers called casks. Over the past 30 years, thousands of shipments of commercially generated spent fuel have been made throughout the U.S. without any radiological releases to the environment or harm to the public. Federal regulations provide for rigorous standards for the design and construction of shipment casks to ensure safe and secure transport of their hazardous contents. Casks must meet extremely demanding standards to ensure their integrity in the most severe conditions, including sabotage. If terrorists did succeed in striking a cask with an explosive during shipment and the cask were breached, the terrorists would also have to succeed in getting the radioactive material out of the container and dispersing it into the environment. The design of casks would make such a release extremely unlikely. After September 11, 2001, the NRC issued to licensees Orders to increase security in the transportation of specific types of radioactive materials, including spent fuel shipments.

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Threats Against Nuclear Facilities

Have there been any threats against nuclear facilities after September 11, 2001?

Although there have been numerous general threats against nuclear facilities since September 11, 2001, none of these threats have been considered credible. The NRC receives a substantial and steady flow of information from the national intelligence community, law enforcement, and licensees that requires prompt evaluation and coordination. Additional information on this subject can be found in the testimony provided by former Chairman Meserve to the U.S. House of Representatives on April 11, 2002.

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Threat Advisory System

How does the NRC communicate information to its licensees about potential threats against their facilities?

When the terrorist attacks occurred on September 11, 2001, the NRC used Advisories to communicate information to the licensees about the appropriate steps to take when there was a threat of terrorist attack. The NRC issued Regulatory Issue Summaries (RIS) 2002-12a, 2002-12b, and 2002-12c, "Threat Advisory and Protective Measures System" that included recommended protective measures for each category of licensee. Some of the information in the various RIS documents are not publicly available because they contain sensitive safeguards and/or classified information.

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Watch List (FBI)

What has the NRC done to ensure that suspected terrorists are not working at nuclear facilities?

Immediately following September 11, 2001, and for several weeks thereafter, the NRC worked with the FBI, the Nuclear Energy Institute (a private organization that represents the nuclear industry), and licensees to review access authorization lists of employees working at nuclear power plants and other licensed facilities to identify any individual whose name also appeared on the FBI Watch List. Based on this extensive review, the NRC and FBI determined that there were no positive matches between the licensees' and the FBI's access authorization lists. The NRC continues to receive a steady flow of information from the intelligence community, law enforcement authorities, and licensees that is evaluated promptly for any possible action.

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Page Last Reviewed/Updated Friday, August 11, 2017