Key Facts
- America’s nuclear energy plants are designed and built to safely withstand a wide variety of natural and other severe events and staffed by highly trained, federally licensed operators with a decades-long history of safe operations in the United States. The operators who staff these plants are capable of taking the actions necessary to control and minimize abnormal events.
- Federal law requires nuclear operating companies to develop and maintain emergency preparedness plans for their nuclear power plants to protect the public. An emergency plan provides an additional layer of protection by specifying response actions that may be taken in the event of a serious accident or event. The independent U.S. Nuclear Regulatory Commission approves each plant’s plan, while approval of companion state and local plans is coordinated between the NRC and the Federal Emergency Management Agency (FEMA).
- An effective emergency response results from mutually supportive planning and preparedness among several parties: companies that operate the plants; local, state and federal agencies; and private and nonprofit groups that provide emergency services. The plans can be implemented during a wide range of severe natural events or security-related events. The companies that operate nuclear power plants pay substantial fees to state and local entities to support emergency preparedness. In 2016, the industry paid more than $78 million in state fees and more than $14 million in local fees.
- Emergency plans continually evolve. For example, changes have included incorporating lessons learned from significant events such as the terrorist attacks of Sept. 11, 2001, and improvements identified during the conduct of emergency response drills and exercises.
Emergency Planning Zones
The NRC and the U.S. Environmental Protection Agency jointly published a report (NUREG-0396/EPA 520/1-78-016) detailing the planning basis for emergency response plans developed by state and local governments. The report determined that the most significant impacts of a nuclear plant accident would be experienced in the area located within an approximately 10-mile radius of the plant. At greater distances—beyond a 10-mile radius—the principal health concern in the event of an accident would be consumption of contaminated water, milk or food.
There are two planning zones:
- a 10-mile emergency planning zone (EPZ) to protect communities from radiation exposure in the event of an accident
- a 50-mile zone within which food products, livestock and water would be monitored to protect the public from radiological exposure through consumption of contaminated foodstuffs
Within the 10-mile EPZ, the immediate protective actions for the public would include instructions for sheltering in place or evacuation. The pace at which an event may unfold—over several hours or days—would provide sufficient time for sheltering or evacuation, if necessary. A study conducted several years ago by the NRC found that, even if operator actions were unsuccessful in stopping an accident, it would “progress more slowly and release much smaller amounts of radioactive material than calculated in earlier studies. … The delayed releases calculated provide more time for emergency response actions such as evacuating or sheltering for affected populations.”
Supplemental protective actions within the 10-mile EPZ might include the distribution of potassium iodide tablets to protect the thyroid gland from radioactive iodine. Within the 50-mile zone, the federal and state governments may monitor and test food and water supplies that potentially could become contaminated and, if necessary, remove any that are found to be unsafe from public consumption.
While both zones were established for planning and preparedness purposes, state government response directors have the authority to expand specific protective actions beyond these zones.
Four Emergency Classification Levels
An emergency at a nuclear energy plant is classified at one of four levels as defined by NRC regulations. These four levels are, from least to most serious: unusual event, alert, site area emergency and general emergency.
- An unusual event is an occurrence that has the potential to impact plant safety. No releases of radioactive material requiring off-site response or monitoring are expected unless further degradation of safety systems occurs.
- An alert indicates that there has been a substantial decrease in the level of plant safety. If there is any release of radioactive material, the off-site doses would be limited to small fractions of the EPA public exposure levels.
- During a site area emergency, major failures of plant functions needed for protection of the public have occurred or are likely to occur. Should there be a radiological release, the off-site doses are not expected to exceed EPA protective action guideline exposure levels except near the site boundary.
- In a general emergency, there is substantial damage to the nuclear fuel, with a potential for loss of containment integrity and a radiation release. Any radiological release could exceed EPA public exposure levels off-site for more than the immediate plant area. There have been no general emergencies since the criteria were established after the accident at Three Mile Island in 1979.
Coordinated Emergency Planning and Response
Emergency preparedness programs for nuclear plants are highly coordinated and rigorously tested, involving the operating companies and local, state and federal agencies. Each entity has specific responsibilities.
- Companies that operate the reactors are committed to operating the plant safely and having an on-site emergency plan and trained personnel capable of implementing diverse and redundant methods to keep the reactor and used fuel in a safe condition. During an event, the company’s trained personnel will immediately implement procedures to respond, classify the emergency, activate the plant's emergency response organization, and notify state, local and federal authorities. The state and local authorities will make the determination of what actions, if any, should be directed to the public. The company also continuously monitors radiation levels and provides this and updated technical information to off-site authorities throughout the event.
- The NRC is responsible for ensuring that the commercial use of nuclear materials is conducted safely. As part of the regulatory process, four regional offices conduct inspections, provide enforcement and review emergency response programs. NRC resident inspectors are on duty at each nuclear plant and have unfettered access. The NRC is the lead agency for coordinating federal actions in response to an accident at a commercial nuclear plant. The agency maintains a headquarters incident response center, where operations officers are on duty around the clock.
- FEMA is responsible for setting standards for off-site emergency preparedness programs and assessing their effectiveness. FEMA’s Radiological Emergency Preparedness Program provides assistance to state and local governments in developing emergency plans for nuclear plants and coordinating with other federal agencies to carry out federal planning and response functions.
Evacuation
As part of emergency preparedness planning, state and local agencies develop detailed evacuation plans for populations within the 10-mile EPZ. These plans typically include several scenarios to reflect such variables as time of day, season, weather conditions and population group (general, transient and special facilities, such as schools and hospitals). The EPZ is subdivided into emergency response planning areas, and population estimates are provided for each area. These plans and evacuation time estimates are updated periodically to reflect population shifts and changes in the transportation network.
Should officials decide to evacuate some areas near the plant, they will map the evacuation areas based on weather conditions and wind direction.
“Evacuation does not always call for completely emptying the 10-mile zone around a nuclear power plant. In most cases, the release of radioactive material from a plant during a major incident would move with the wind, not in all directions surrounding the plant,” according to the NRC. “The release also would … become less concentrated as it travels away from a plant.”
Responder Training, Practice and Evaluation
Plant personnel assigned to the emergency response team must participate in initial and periodic requalification training. Energy companies also offer specialized training to off-site personnel who may be first-responders to a plant emergency (for example, local ambulance or firefighting crews). Off-site agencies also conduct training.
All nuclear plants must participate in federally evaluated, full-scale emergency response exercises every two years. The NRC also requires nuclear plants to conduct training drills in alternate years to test and maintain their emergency response capabilities. State and local emergency management officials participate in these drills.
Following each drill and exercise, the company and participating federal, state and local emergency response personnel conduct an in-depth critique of their performance to identify areas needing improvements. Significant issues are placed in the company’s corrective action tracking system to ensure proper evaluation and resolution, which is subject to inspection by the NRC.
Experience with Emergency Plans
Emergency plans for U.S. nuclear plants have been activated in response to relatively minor events. More frequently, however, local officials have used emergency response plans developed in conjunction with the nuclear industry to respond effectively to hazards that have no connection to the nuclear plant. For example, hurricane readiness in the Southeast benefits from detailed nuclear plant emergency planning.
Nuclear plant emergency preparedness also helped one community deal with a very different and unexpected type of emergency. When a shooter attacked two military installations in Chattanooga, Tennessee, in July 2015, local emergency management authorities drew on the relationships and communications links established through their experience with nuclear power plant emergency preparedness during routine drills and exercises. The local officials approached the Tennessee Valley Authority for assistance with the hundreds of news media expected to cover the incident. In response, TVA activated its Joint Information Center in record time. The facility was used for about a week.
Industry Committed to Preparedness
Emergency preparedness at U.S. nuclear plants is an integral part of daily operations. The industry demonstrates its continuing commitment to emergency preparedness by constantly exercising emergency plans and procedures, upgrading emergency response facilities and equipment, and conducting responder training and drill programs to maintain proficiency. Each company works with its state and local public safety partners to ensure that the response capability is comprehensive and well-integrated to ensure public health and safety.