Written by S. Fred Singer
January 17, 2009
S. Fred Singer
The adequacy of fissionable material may become a serious problem in the decades ahead. In principle, the world's supplies of uranium are inexhaustible. After commercially useful ores become depleted, however, one has to rely on granites and ultimately on sea water, where the recovery costs may become prohibitive.
At the same time we will have available huge amounts of spent fuel containing fissionable
U-235 and plutonium isotopes that could be recycled into new fuel elements. In addition, the greatest resource could come from the non-fissionable U-238 in spent fuel, from depleted uranium, and from vast natural resources of thorium ores. To turn these into useful fissionable material that can be burned in conventional reactors requires not only recycling and reprocessing of spent fuel but also the construction of breeder reactors or the use of fusion processes and other means that create neutrons -- which can in turn transform non-fissionable materials into fissionable ones.
By 2015 there will be enough spent thermal-reactor fuel on hand (globally) to start up 200-300 GWe of breeder reactors, with some 10 GWe's worth more coming in every year. Clearly, with proper planning NOW we won't be hurting for fissile material for decades. Once established, breeders can propagate themselves at a rate of 5-10% per year, depending on reactor parameters.
One useful byproduct of reprocessing and recycling, if done properly, is the elimination of long-lived radio-isotopes which removes one of the chief concerns about the handling of spent nuclear fuel. One such concept is the Integrated Fast Reactor (IFR), which can burn up these trans-uranic isotopes.
The technical problems are vast but the political problems may be even greater. There have been long-standing objections in the US (but not in the UK or France) to reprocessing spent fuel and to the construction of breeders because of fear of nuclear weapons proliferation. There is also legislation, going back to 1982, mandating the permanent underground disposal of spent fuel without any reprocessing - a once-through use of uranium that is clearly wasteful and also environmentally controversial.