Last month I promised to recount William Tucker’s excellent chapter on nuclear waste reprocessing from his outstanding book Terrestrial Energy. After considerable study of this issue, I can report Tucker did the job about as well as it can be done.
There is no simple way to explain the chemical engineering involved in nuclear waste reprocessing. It is elegant but by no means simple. Thus I can only paraphrase his exceptional effort to make the complex more understandable.
No Such Thing as Waste
In strict physical terms, there is no such thing as nuclear waste. Using a resource does not automatically turn it into waste. As environmentalists have long taught us, pollution is really just resources out of place.
The by-products of nuclear fission are so incredibly compact and potentially useful, none of them need to be thrown away. They are sitting there waiting to be processed. Almost 100 percent of the material in spent nuclear fuel rods can be recycled as useful material, and it is being done in other parts of the world today.
The very small amounts of material that cannot be reprocessed economically today can be stored safely until it becomes financially feasible in the future. There truly is no such thing as nuclear waste.
All Is Usable
More than 95 percent of a spent fuel rod is uranium-238, the same material we initially mine from the Earth. In nearly every other country in the world with nuclear power plants, this uranium-238 is reused to create more nuclear energy.
The remaining 5 percent is too intensely radioactive to be used for the fission process, but it has other uses. These radioactive isotopes have found broad implementation in medicine and industry. Forty percent of all medical procedures now involve some kind of radioactive isotopes, such as the tracers commonly used in diagnostics and the energy sources used to fight cancer.
Global Reprocessing
So why are we making such a fuss over the proposed and long-delayed Yucca Mountain repository for nuclear waste? The answer is that we stopped reprocessing nuclear fuel rods in the 1970s because we were afraid recycling would lead to proliferation of nuclear weapons in other countries. This concern has proven totally unwarranted.
While the United States gave up reprocessing, Canada, England, France, Japan, and Russia did not. All now have a recycling industry and very little waste storage problem.
Reprocessing Procedures
All commercial reprocessing plants use the well-proven hydrometallurgical plutonium uranium extraction process, called PUREX for short. This involves dissolving the fuel elements in concentrated nitric acid. Chemical separation of uranium and plutonium is then undertaken by solvent extraction steps, (neptunium, which may be used for producing plutonium-238 for thermal-electric generators for spacecraft, also can be recovered if required).
The plutonium and uranium can be returned to the input side of the fuel cycle—the uranium goes to the conversion plant prior to re-enrichment, and the plutonium goes straight to mixed oxide (MOX) fuel fabrication.
Alternatively, some small amount of recovered uranium can be left with the plutonium sent to the MOX plant, so the plutonium is never separated on its own. This is known as the co-extraction process (COEX) developed in France but not yet in use.
U.S. Plant Under Construction
President Ronald Reagan lifted the reprocessing ban in 1981, but Congress did not allocate the substantial subsidy that would have been necessary to start commercial reprocessing efforts.
In 1999 the Department of Energy signed a contract with a consortium of U.S. companies to design and operate a mixed oxide fuel fabrication facility at the Savanna River site in South Carolina, which began construction in October 2005.
I’ll present more on reprocessing and Bill Tucker’s marvelous book Terrestrial Energy next month.
Jay Lehr, Ph.D. ([email protected]) is science director of The Heartland Institute.
