Casual Conversation

That is a misleading title for the article as written, but the editor’s footnote explains it:

Editor's Note (12/30/08): In response to some concerns raised by readers, a change has been made to this story. The sentence marked with an asterisk was changed from "In fact, fly ash—a by-product from burning coal for power—and other coal waste contains up to 100 times more radiation than nuclear waste" to "In fact, the fly ash emitted by a power plant—a by-product from burning coal for electricity—carries into the surrounding environment 100 times more radiation than a nuclear power plant producing the same amount of energy." Our source for this statistic is Dana Christensen, an associate lab director for energy and engineering at Oak Ridge National Laboratory as well as 1978 paper in Science authored by J. P. McBride and colleagues, also of ORNL.; As a general clarification, ounce for ounce, coal ash released from a power plant delivers more radiation than nuclear waste shielded via water or dry cask storage.

It’s interesting that less radiation is emitted by shielded nuclear waste than fly ash, but the word “shielded” is doing a lot of heavy lifting there. I’d also expect nuclear waste to be a lot denser than coal ash, but that might even out with the relative quantities produced.