MASS EVACUATION: More than 180 million people live within 50 miles of a nuclear power plant in the U.S.--the radius the U.S. suggested be evacuated during the nuclear crisis at Fukushima Daiichi. Image: © Taber Andrew Bain
On March 11, 2011, Japan suffered a massive earthquake and subsequent tsunami that destroyed roads, bridges, and buildings; killed nearly 16,000 people; and critically disabled three reactors at the Fukushima Daiichi nuclear power plant. By March 12, the U.S. Nuclear Regulatory Commission (NRC) was already considering urging Americans within 50 miles of the stricken nuclear reactors to evacuate, given an explosion in Unit 1 that destroyed the reactor building and exposed spent nuclear fuel and other radioactive materials to the air.
"If this happened in the U.S., we would go out to 50 miles," said Bill Borchardt, NRC executive director for operations on March 17, according to transcripts of the days following the catastrophe. "That would be our evacuation recommendation."
In fact, in the U.S., more than four million Americans live within 10 miles of the 63 sites of nuclear power plants with at least one operating reactor, according to data compiled by the NRC based on the 2000 census. That number swells when the radius extends outward to 50 miles to affect more than 180 million Americans, and includes major metropolitan areas such as New York City, Philadelphia, San Diego and even West Palm Beach, Fla.
In the wake of the meltdowns in Japan and subsequent evacuations, could all these people in the U.S. be evacuated--or take some form of protective action--in time in similar circumstances?
Planning for the worst
Nuclear power plants are surrounded by two "emergency planning zones" developed out of accident analyses conducted in the 1960s and 1970s: a roughly 10-mile radius around the plant that must anticipate being exposed to a radioactive plume and a roughly 50-mile radius around the plant that must prepare for possibly being exposed to radioactive particles that drop out of a plume. "Neither are zones that are fixed and that is the absolute boundary," explains the NRC's Patricia Milligan, the senior technology advisor for preparedness and response in the Office of Nuclear Security and Incident Response. "We don't expect that [nuclear power plant operators] would stop taking action because it's at 10.5 miles. The plans are built so that 10 miles provides a reasonable basis and, if you need to expand, you could."
That is exactly what happened in the case of Fukushima. Just hours after the tsunami on March 11 the Japanese government ordered an evacuation of those living within three kilometers of the stricken nuclear reactors and suggested those living within 10 kilometers stay indoors with the windows closed. As the situation progressively worsened--and radiation hot spots were discovered farther afield--the Japanese government expanded the evacuation order.
The goal in the zones prescribed by U.S. regulations is to avoid any radiation doses that exceed the U.S. Environmental Protection Agency's "protective action guidelines" for exposure to a plume of radioactive material being released from a nuclear power plant. The U.S. rules note that evacuation--or sometimes getting indoors--"should normally be initiated at one rem," or 10 millisieverts. (A rem is a dosage unit of x-ray and gamma-ray radiation exposure.)Workers within a nuclear power plant can receive doses of up to 50 millisieverts per year. It takes immediate exposure to as much as two sieverts of radiation to cause sickness straightaway.