The Manhattan Meltdown Scenario

Indian Point officials brief the press during a drill. Bettmann-Corbis

The two operating nuclear reactors known as Indian Point are situated in Buchanan, N.Y.—just 35 miles from midtown Manhattan. More than 17 million people live within 50 miles of these plants.

How might a meltdown start? An earthquake, obviously, is among the scenarios. Others include various forms of terrorist attacks. Regardless of the trigger, a meltdown would follow several specific stages.

First, as cooling water dissipated from the reactor core, intensely hot radioactive pellets in the fuel rods would overheat and swell, and their zirconium cladding would oxidize and rupture. Then the pellets themselves would begin to melt. (Many details described here reflect a study of Indian Point by Edwin S. Lyman.)

If the molten fuel core were to hit the bottom of the reactor vessel, it would trigger massive steam explosions that could blow the reactor vessel apart. The eventual distribution of radioactive elements would depend on several factors, including the weather.

Both the Nuclear Regulatory Commission and the Environmental Protection Agency require an evacuation plan for a 10-mile radius of the reactor: an off-site alarm set to go off 30 minutes after an event began would allow time for the operators to determine the extent of the damage. That would leave 78 minutes from the alarm's sounding to the beginning of the radioactive release.

Early fatalities from acute radiation sickness for those within the 10-mile evacuation zone would range from 2,440 to 11,500. Late cancer deaths, which would occur two to 60 years later, could range from 28,100 to a staggering 518,000 people in the 50-mile zone.

Fatalities could be reduced within the 10-mile zone if people were to shelter indoors during the acute phases of the radioactive fallout. (Evacuation tends to increase doses received, because people would be in non-airtight vehicles or on foot.) Also, if everyone were to take inert potassium iodide tablets immediately, peak doses to their thyroids of radioactive iodine could be cut by 30 percent.

Imagine the scene: more than 300,000 people are running and driving away from the stricken reactor along winding Westchester roads, trying to reach their children, their spouses, and their mates. Then they begin to taste a strange, metallic flavor in their mouths. The radio blasts out dire warnings, yet nobody knows what they are doing and nobody is in control.

The economic consequences of a meltdown would be stupendous. New York could be rendered virtually uninhabitable, with $1 trillion or more in costs from attempts at decontamination, the condemnation of radioactive property, and compensatory payments to people forced to relocate temporarily or permanently. Add to that the extraordinary economic consequences if the world's financial capital were closed forever.

Caldicott, who was trained as a pediatrician, is cofounder of Physicians for Social Responsibility. Adapted from Nuclear Power Is Not the Answer copyright 2006 by Helen Caldicott. Reprinted by permission of the New Press.