As bad as it's gotten
Rulemaking is based on the best available data. So what has been learned from previous close calls from nuclear and nonnuclear incidents alike? On March 28, 1979, the nuclear power plant at Three Mile Island in Pennsylvania suffered a partial meltdown that led to the release of radioactive materials. In the fog of confusion that surrounded the event, Pennsylvania government officials advised children and pregnant women within a five-mile radius of the facility to leave. That radius of evacuation ultimately extended some 20-miles around the plant, although the majority of local residents did not evacuate. Those who stayed were urged to remain indoors and farmers were urged to shelter their animals and feed them stored food.
In the end, despite the partial meltdown and release of radioactive material, numerous studies have found limited or no health effects. But the worst accident in U.S. commercial nuclear power history did point out flaws in evacuation planning. "Three Mile Island was a very enlightening accident in terms of how an accident progresses," Milligan notes.
First and foremost, it became clear that nuclear accidents to date, including Fukushima, are slow-moving affairs. In the case of Fukushima, there were at least 14 hours between the loss of electricity to power the pumps keeping cooling water on the nuclear fuel and a melt down. In nonnuclear emergencies, such as the release of toxic gases, only minutes may pass before catastrophe hits. "When there's conditions immediately dangerous to life and health, you don't have hours, you have significantly less time than that to get people out of the way of chlorine gas or a wildfire," Milligan says. Nuclear accidents also tend to affect a much smaller area than, for example, a major hurricane like Katrina that covered a swath of territory 400 miles wide and caused approximately two million people to evacuate Alabama, Louisiana and Mississippi coastal areas. "Evacuations can occur very effectively and very quickly in this country," Milligan adds.
Evacuations around nuclear power plants in the U.S. are rare but getting people out and away from their homes is relatively commonplace. Evacuations of more than 1,000 people occur all too frequently in the U.S.--230 occurred between 1990 and 2003, a 2005 study from Sandia National Laboratories found. "A significant evacuation occurs on average every three weeks," Milligan notes, for causes ranging from deadly chlorine clouds to wildfires. "Almost all are ad hoc evacuations," meaning no one has practiced or planned for such events, unlike the nuclear industry. For example, a chemical fire and explosions at a hazardous waste facility in Apex, N.C., required the evacuation of approximately 17,000 people in a roughly four-mile radius late on the night of October 5, 2006, although the officials charged with carrying it out could call on the planning for the 10-mile evacuation zone around the Shearon Harris nuclear plant nearby.
Still, radioactive iodine released from a nuclear power plant accident can travel far and fast. To cope with that, the NRC requires that potassium iodide pills that can block the human thyroid from taking up radioactive iodine be available to those living within 10 miles of a plant--but no further. "You could get a dose out at 50 miles, especially to children, that significantly increases their likelihood of getting thyroid cancer later in life," notes physicist Frank von Hippel of Princeton University, co-chair of the International Panel on Fissile Materials. "I would have chosen 50 miles or even beyond for potassium iodide availability on an emergency basis."