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Nuclear Energy Insight

Spring 2012—After the accident at Japan’s Fukushima Daiichi nuclear energy facility, the plant operators and public officials executed plans to keep people nearest the plant safe from any release of radiation, utilizing an emergency planning zone that extended in a 6-mile and, later, 12-mile radius around the plant.

Insight Spring 2012 EPZThough the Japanese response proved effective in protecting its citizens while avoiding widespread displacement, some Americans questioned the adequacy of the 10-mile emergency planning zone used at U.S. reactors.

For example, Sen. Bob Casey (D-Penn.) said in a letter to the Nuclear Regulatory Commission “that millions of Pennsylvanians living in close proximity to nuclear power plants [must] know that the unique characteristics of each plant have been taken into account in the development of evacuation plans.”

About 4.6 million Americans live within 10 miles of an operating nuclear energy facility, in what is called an “emergency planning zone.” While evacuation plans are part of safety planning, emergency planning zones are not synonymous with evacuation.

Most residents in an emergency may only be asked to stay informed by listening to emergency alert system messages from public safety officials. Some may be instructed to close their windows and stay indoors if there is a release of radiation.

Sue Perkins-Grew, NEI’s director of emergency preparedness, said that the concept of emergency planning zones is “based on sound science and research performed by [the U.S. Environmental Protection Agency] and other federal agencies.”

“Evacuation rarely calls 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 independent U.S. Nuclear Regulatory Commission. “The [radiation] release also would … become less concentrated as it travels away from a plant.”

For planning purposes, the NRC defines two zones around each nuclear power plant. The exact size and configuration vary from plant to plant, answering Sen. Casey’s question about the unique nature of each plant and its surrounding community.

What the NRC calls the “plume exposure pathway” has a radius of about 10 miles where there could be an exposure to radioactive materials. The “ingestion pathway” is about 50 miles in radius to prevent potentially contaminated food, water and vegetation from being consumed.

If evacuation or sheltering is required, the area might extend beyond the 10-mile radius, depending on local conditions.

The EPZ, as it is called, defines the area for planning response to a radiological accident.

During the highest-level general emergency, people closest to the facility would be evacuated first, then public safety officials would make additional decisions to either evacuate people in larger surrounding areas or to order them to stay indoors.

“People living in the remainder of the 10-mile zone will most likely be advised to go indoors to monitor Emergency Alert System broadcasts,” the NRC fact sheet says.

“The idea of the 10-mile EPZ,” said Perkins-Grew, “is to protect the communities that are closest to the facilities. Public safety officials would make decisions based on conditions to either shelter-in-place or to evacuate or a combination of both. Those same public safety officials have the flexibility, if the event were to be prolonged, to make the same decisions beyond the 10-mile emergency planning zone.”

Companies that operate nuclear energy facilities are required by the NRC to have an on-site emergency plan. If there is an accident, facility workers will immediately implement procedures to respond to it, classify it, notify state, local and federal authorities, and activate the plant’s emergency response organization.

Each facility owner is required to hold exercises on its emergency plan every two years with the NRC, the Federal Emergency Management Agency (FEMA) and local authorities. FEMA sets standards for off-site emergency preparedness plans and assesses their effectiveness. The NRC regulates emergency response on the plant site.

Perkins-Grew pointed out that the standard “plans have been matured over decades.”

“We have very good integrated training programs and evaluated exercises,” she said. “So there is constant interaction between the power plant operators and state and local safety officials.”

In more than five decades of operation at nuclear energy facilities in the United States, there have been no injuries or fatalities caused by exposure to radiation.

Read more articles in Nuclear Energy Insight and Insight Web Extra.