Recycling Used Fuel

The term “recycle” means to reclaim, reprocess, reuse, salvage or save. Humans have been recycling materials and resources since pre-historic times. Traditionally, the things that were recycled were those that were deemed valuable or in short supply. Today, we recycle a multitude of items including paper, cardboard, plastic, metals, solvents, motor oil, appliances, automobile parts, batteries and organic materials.

Some of these materials are recycled because they are in short supply and need to be conserved, while other materials are recycled to divert them from landfills or to prevent them from being released into the environment. It is only in recent years that the idea of recycling as a means of helping protect the environment has become part of our culture.

What about nuclear fuel? Can it be recycled? The answer is yes. Reprocessing is to nuclear waste what recycling is to regular garbage: it removes some useable (fissile) materials from spent fuel that can be reused to generate more electricity. The reprocessing of nuclear fuel achieves both goals of recycling: it conserves resources and helps protect the environment because it “extends fuel supplies and reduces the radioactivity and quantity of waste to be disposed.”

As fuel is burned in a CANDU reactor, some, but not all, of the uranium-235 is depleted. At the same time, some plutonium-239, a fissile material, is created. Thus the amount of fissile material in irradiated fuel is only decreased by 30% from that in the fresh fuel. Irradiated fuel is removed from the reactor, not because there is no more energy to extract, but because too many neutron-absorbing fission products have built up.

Reprocessing is a complex, chemical process that involves chopping up spent-fuel elements and dissolving the pieces in nitric acid. Chemical separation of uranium and plutonium follows. These must be done by remote control in shielded rooms due to the high radioactivity of the spent fuel. The extracted uranium is returned to the conversion step prior to fuel fabrication; and the plutonium goes straight to the fuel fabrication plant.

The reprocessing of nuclear fuel is not a new idea. In the past 40 years, more than 55,000 tonnes of spent fuel from electrical power reactors have been reprocessed. Great Britain, France, Russia and Japan all have used fuel reprocessing facilities. Presently, Canada does not reprocess used nuclear fuel for three reasons: the high cost of reprocessing, Canada has large uranium reserves and “the concern that plutonium could be diverted and manufactured into nuclear weapons.” The diversion of plutonium for nuclear weapons in Canada is unlikely because of the many safeguards put in place by the Canadian Nuclear Safety Commission and the International Atomic Energy Agency (IAEA). In the future, because reprocessing conserves uranium resources as well as reduces the toxicity of used nuclear fuel, reprocessing may have a role as part of Canada’s Adaptive Phase Approach for the long term disposal of nuclear waste.

Sources:

English Collins Dictionary – English Definition & Thesaurus.
Hans Tammemagi and David Jackson, Unlocking the Atom: The Canadian Book on Nuclear Technology: (McMaster University Press, 2002) ,194.