Nuclear energy promised to generate low-cost electricity safely, with fewer environmental and health problems from air and water pollution than fossil-fueled power plants. For a number of reasons, that promise has not been fulfilled.
However, in addition to new designs for uranium-fueled reactors, efforts are underway in a number of countries to develop commercial nuclear reactor designs that could solve many of the problems encountered with existing uranium-fueled nuclear power plants. This new generation of reactors will be fueled by thorium (Th-232) instead of uranium (U-235).
Thorium-fueled reactors have a number of advantages over uranium reactors, including less potential for nuclear proliferation and less waste.
- Thorium is three times as abundant in the Earth’s crust as uranium, and there are thorium-bearing ores identified in many countries.
- Currently operating nuclear reactors are inefficient in extracting energy from uranium. Only about 3 percent of the uranium in the rods is consumed before the rods must be replaced, due to the buildup of fission byproducts in the rods.
- Fission byproducts in liquid thorium salts, by contrast, can be removed and reprocessed to produce additional fuel stock, while the reactor continues to operate.
Thorium-based reactors have been shown to be more economical than uranium-fueled reactors. In contrast to conventional light water reactors using uranium, according to a 2013 report from the Bellona Foundation:
- The capital costs of thorium reactors would be lower than conventional nuclear reactors; a 1 gigawatt (GW) thorium power plant would cost at most an estimated $780 million in comparison to capital costs currently of $1.1 billion per GW for a uranium-fueled reactor.
- Less manpower would be required to operate the plant; for a 1 GW power plant, staffing costs may decrease from $50 million to $5 million.
- Less radioactive waste is produced, perhaps one-tenth as little, by volume; thus, nuclear waste disposal for a 1 GW thorium power plant would cost an estimated $1 million or even less per year.
There are technical challenges in designing an efficient thorium-fueled nuclear reactor, but current development efforts underway will likely lead to a commercially practical system. The relative abundance, greater safety and lower cost of thorium-fueled systems could help fulfill the promise of nuclear power.