Nuclear Reactors 331 - Thorium Versus Uranium As a Nuclear Fuel
I have blogged about thorium as a possible fuel several times. There are thorium enthusiasts that believe that thorium would be a better fuel for nuclear reactors than uranium. There are critics who would disagree.
Thorium reactors would utilize a fission reaction which would share many problems of uranium reactors. Thorium is abundant and easily accessible uranium reserves are running out. Thorium reactors do not produce plutonium and other transuranic elements like uranium reactors do. On the other hand, there would still be problems with mining and fabricating fuel, safety of reactors, creation of radioactive wastes and proliferation of nuclear weapons even without plutonium production.
With respect to safety, the U.S. Department of Energy conducted a review in 2009 and concluded that "the choice between uranium-based fuel and thorium-based fuel is seen basically as one of preference, with no fundamental difference in addressing the nuclear power issues [of waste management, proliferation risk, safety, security, economics, and sustainability].”
With respect to waste, thorium fuel produces long-lived hot isotopes which means that there would still be radioactive waste that would have to dealt with. It turns out that spent thorium fuel is actually more radioactively toxic than spent uranium fuel in the long term.
With respect to proliferation dangers, while it is true that thorium reactors do not produce plutonium, thorium can be converted to uranium-233 which is fissile and can be used to make nuclear bombs. A report commissioned by the U.K. Department of Energy and Climate Change ended with the conclusion that "claims by thorium proponents who say that the radioactive chemical element makes it impossible to build a bomb from nuclear waste, leaves less hazardous waste than uranium reactors, and that it runs more efficiently, are overstated."
There were early experiments with thorium reactors but these efforts were abandoned decades ago. Currently there are only laboratory experiments, computer studies and possible designs for thorium reactors. When and if prototype commercial thorium reactors are built, unanticipated problems might arise to complicate the design of thorium fuelled reactors. In any case, it will be more than a decade before any thorium reactor could go into commercial operation.
Some studies of thorium for use as a fuel have concluded that they cannot compete economically with uranium reactors because thorium fuel would require a more complex process for fabricating the fuel rods. A Norwegian thorium commission said that there were many uncertainties and problems associated with the use of thorium as a fuel. The commission concluded that any such reactors were far in the future at best and that a massive international research effort would be necessary to design and build them. India which has massive reserves of thorium has expressed interest in developing thorium reactors so they can be self-sufficient. Other countries are conducting research on thorium reactors.
Unfortunately, the bitter lesson has been learned from over a half-century of nuclear power that the promise of cheap, safe and clean nuclear energy has failed to materialize and similar promises for thorium power should be taken with a grain of salt.
