by Jeff Danner – Common Science
Posted Sep 23 2012 8:39PM
While nuclear power plants generate a variety of radioactive wastes, by far the most difficult to manage are the spent fuel rods. Spent fuel rods contain unutilized uranium as well as a mixture of different radioactive elements which are members of the uranium-235 decay chain. The fuel rods will continue to pose serious danger to human health for millions of years.
The world has already generated a staggering amount of nuclear waste to which we are adding approximately 12,000 tons per year. All of this has occurred without a clear plan to manage the waste. While we continue to evaluate the potential long-term storage options, most of the world’s nuclear wasted is staged in temporary above-ground storage facilities where it has been incorporated into glass and ceramic composites, sealed in metal containers, and encased in concrete. This storage approach is sufficient to protect us from radiation in the short term, but is not sufficient to isolate the waste for the millions of years that will be necessary.
A comprehensive review of all of the long-term storage options being considered would be too much to cover in a single column. Any acceptable solution needs to completely and reliably isolate the waste from the biosphere for five to ten million years. There are two out-of-the-box type solutions that I find interesting. The first is ejection into space. This certainty removes the waste from the biosphere. The Achilles Heel of this approach is the possibility of an upper atmosphere explosion of the rocket transporting the waste to space, the results of which would be catastrophic. Personally, I am intrigued with a second creative proposal which suggests that we consider transporting the waste to a subduction zone at the intersection of two tectonic plates at the bottom of the ocean. Material placed into the subduction zone would be transported into the earth’s magma miles below the surface. Concerns regarding potential contamination of the oceans during the operation have stalled these efforts as well. While both of these esoteric options would meet the criteria for removing the wastes from the biosphere, their attendant risks suggest that they will never be implemented.
This leaves us with the less elegant and long debated issue of burying the waste. For the last four decades the U.S. has been evaluating the option of interring our nuclear waste beneath Yucca Mountain in Nevada. Political pressures and scientific uncertainty have thus far, kept this project from moving forward. My sense is that eventually we will have a serious incident at one of our above-ground, temporary waste storage facilities which will finally force the Yucca Mountain project to move forward.
With the serious and long-term risks associated with nuclear waste, one must consider whether the benefits of nuclear power are worth it.
Read also Nuclear Power Part I: The Science