The cost of living near nuclear power

A nuclear accident nearby poses two main health threats: direct radiation from the damaged reactor and ingestion, typically by breathing, of a radioactive isotope such as iodine-131 or cesium-137 that has become airborne from an explosion.

Ingestion is the greater health threat because of its potential to concentrate radiation within the body. Iodine-131 typically leads to cancer of the thyroid, especially in children. Cesium-137 can contribute to a wide variety of cancers.

Direct radiation, by contrast, dissipates rapidly the farther away you are from the source. "Distance is obviously a very large player here, as is the direction of the wind," says Miller.

So how close is too close?

"A 10-mile or so radius is more than sufficient," Miller says. "There is always the statistical chance of cancer in the future, but in the Japanese situation, with the doses we've seen, even the workers at the plant might have a one-half (percent) to 1 percent increased cancer risk over their lifetimes. A mile away, that radiation level is way, way down by comparison."