Thorium, a slightly radioactive metal that occurs in rocks and soils, may hold significant promise as a replacement for uranium in the nuclear energy sector.
As global energy consumption increases, thorium is being looked into as a possible alternative to uranium to provide safe and abundant nuclear power at a reasonable cost. For example, India has been interested in thorium-based nuclear energy for decades, according to the US Geological Survey.
Thorium in the works
The question of whether thorium works for energy production was answered in 2013, when a private Norwegian compan, Thor Energy, began to produce power at its Halden test reactor in Norway using thorium.
“It is the fundamental first step in the thorium evolution,” Thor Energy’s CEO, Oystein Asphjell, told Reuters.
Nuclear giant Westinghouse, a unit of Toshiba, is part of an international consortium that Thor Energy established to fund and manage the experiments.
As part of its ongoing research into thorium as a nuclear fuel, Thor Energy created an international consortium that is charged with funding and managing thorium experiments. One of the consortium’s members is none other than Westinghouse, an established player in nuclear energy; the company provides viewpoints on the research.
But Thor Energy is not the only company engaged in researching whether or not thorium is a viable alternative to uranium in nuclear energy. Firms from the US, Australia and the Czech Republic are also working on thorium reactor designs and other elements of fuel technology using the metal. However, Thor Energy was the first off the block to begin energy production with thorium.
How thorium energy works
Unlike uranium, thorium can’t split to make a nuclear chain reaction — in scientific terms, it isn’t fissile. However, if it is bombarded by neutrons from a fuel that is fissile, like uranium-235 or plutonium-239, it’s converted to uranium-233, itself an excellent nuclear fuel. After the process begins, it’s self-sustaining — fission of uranium-233 turns more thorium nearby into the same nuclear fuel. There are complexities beyond the scope of this article, including the mechanics of molten-salt versus pressurized-water reactors in burning thorium, but the reaction described above is the main appeal of thorium, and its principal promise.
Thorium vs. uranium
Thorium is an appealing alternative to uranium to many countries. It is both more cheap and more abundant than uranium, whose price is expected to rise yet more as backlash from the Fukushima disaster dies down, according to Energy and Capital. There are other benefits of thorium as well. During a thorium-powered nuclear reaction, most of the thorium itself is consumed, which leads to less waste, most of which is rendered non-hazardous in 30 years. The most dangerous nuclear waste material currently in use must be stored for 10,000 years, by way of contrast. Furthermore, 1 metric ton of thorium is equal to 250 metric tons in terms of efficiency in a water reactor.
Extraction of thorium would be less expensive per unit of energy than extraction of uranium as well, because it is present in higher concentrations by weight than the other metal, according to Dauvergne. The source also mentions another peculiar trait of thorium: it is nearly impossible to weaponize, as it contains no fissile isotope. This in itself has slowed uranium research, according to a 1997 international scientific symposium on nuclear fuel cycles.
The dangers of uranium – widely publicized in the wake of the Fukushima disaster – often lead analysts and others to consider thorium more seriously. As thorium is not fissile on its own, reactions could be stopped in case of emergency, according to Forbes. The publication suggests thorium could allow countries like Iran and North Korea to benefit from nuclear power without causing concern that they are secretly developing nuclear weapons, as well.
Thorium can also be used together with conventional uranium-based nuclear power generation, meaning a thriving thorium industry would not necessarily make uranium obsolete.
Where thorium is found
Thorium is present in small quantities in soils and rocks everywhere, and it’s estimated to be about four times more plentiful than uranium. Large reserves, rather than the trace amounts of the metal in the average backyard, exist in China, Australia, the US, Turkey, India and Norway, according to Reuters.
The US Geological Survey compiled a document listing its domestic thorium resources. The metal is found in epigenetic vein deposits, low-grade deposits and black sand placer deposits. In its many locations, thorium can be found in Montana, Idaho, Colorado, the Carolinas, Florida and Georgia. This is a huge range of locations for possible thorium exploration, development and production.
Of course, the US is not the only country with sizable thorium reserves. The others listed above also have plenty of options should energy and resource companies decide to develop the thorium reserves within their borders.