Uranium market watchers and proponents of nuclear power have undoubtedly encountered thorium, the unicorn in the room when it comes to clean energy. As the world's nuclear energy consumption increases and future supply of uranium remains uncertain (although there are more nuclear reactors being built around the world) thorium is being looked into as a possible alternative to uranium to provide safe and abundant nuclear power at a reasonable cost.
But what is thorium and how can it play into the global energy future?
Thorium, a slightly radioactive metal that occurs in rocks and soils. It is more abundant in nature than uranium and is fertile rather than fissile. When placed into nuclear applications, thorium can be used in conjunction with a fissile material like recycled plutonium.
The use of thorium as a primary source of energy is still in the works. As World Nuclear Association (WNA) notes, extracting the latent energy value of thorium in a cost-effective manner is still challenging. This means that before the the energy sector can turn to thorium as a viable option, there is still a lot of research and development that needs to go into refining the technology.
Thorium in the works
The question of whether thorium works for energy production was answered in 2013, when privately owned Norwegian company 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 at the time.
Nuclear giant Westinghouse, a unit of Toshiba (TSE:6502), is part of an international consortium that Thor Energy established to fund and manage the experiments. An established player in nuclear energy, Westinghouse provides viewpoints on the research.
Thor Energy is not the only company engaged in researching whether or not thorium is a viable alternative to uranium in nuclear energy. In fact, firms from the US, Australia and the Czech Republic have also been working on thorium reactor designs and other elements of fuel technology using the metal. However, Thor was the first to begin energy production using the radioactive metal.
But the Norwegian company is not the only one making strides in the thorium space. In fact, India has been interested in thorium-based nuclear energy for decades, according to the US Geological Survey (USGS). The country's nuclear developers have designed an advanced heavy water reactor that is specifically aimed at using thorium as a fuel.
Also looking at the prospect of thorium as a fuel source is China, who signed a phase two agreement in 2009 to study the commercial and technical feasibility of its full-scale use in the Candu power system, a heavy water reactor that uses thorium-based fuels. China's thorium production goal has been set for 2020.
In Indonesia, the country's industry minister, Saleh Husin, has suggested that Indonesia pursues development of thorium-fueled nuclear power plant to take advantage of radioactive material in the country and ensure energy supply for industrial developments.
In a statement from May 2016, Husin said, "Thorium is abundant in Bangka Belitung." He added it is estimated that a thorium-based power plant would only cost three cents per kilowatt hour of energy.
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.
WNA highlights that an "important principle in the design of thorium fuel systems is that of heterogeneous fuel arrangement in which a high fissile (and therefore high power) fuel zone called the seed region is physically separated from the fertile (low or zero power) thorium part of the fuel -- often called a blanket. This serves to better supply extra neutrons with thorium nuclei, enabling them to convert to fissile U-233.
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 as it is both cheaper and more abundant than uranium. Furthermore, 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 isotopes. That 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. What's more, 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.
Thorium can also be used together with conventional uranium-based nuclear power generation, meaning a thriving thorium industry would not necessarily make uranium obsolete.
Interestingly, the idea of using thorium as an alternative to coal in the US came up recently following the release of President Barack Obama's final version of the Clean Power Plan. During a talk at the Harvard iLab, Harvard Business School Professor Joe Lassiter discussed why he believes nuclear power is an essential ingredient in fighting the worldwide threat of coal-fired power plant emissions, noting both uranium and thorium as viable alternatives.
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 USGS 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.
The US isn't the only place that contains thorium resources. According to the USGS, in 2014 exploration and development of rare earths projects associated with thorium were underway in Australia, Brazil, Canada, Greenland, India, Russia, South Africa, the United States and Vietnam.
Skyharbour Resources (TSXV:SYH) is one company with thorium exploration in the works. Its Falcon Point uranium and thorium project is located in the Athabasca Basin in Saskatchewan. And while the project is still in its early stages, the company released assays from a drill program there in June, showing intersections of 0.172 percent U3O8 and 0.112 percent ThO2 over 2.5 meters.
Thorium Power Canada, in partnership with DBI, has designed thorium reactors, with a planned 10 MW reactor in Chile. Thorium Power Canada estimates the reactor will provide enough power to produce 20 million litres per day at the desalination plant, which is the equivalent of powering 3,500 homes.
In Indonesia, Thorium Power is currently preparing for a proposal for development of a 25 MW thorium reactor.
There are also quite a few rare earths companies that have found thorium at their respective properties, in both alkaline rock complexes and vein-type deposits. A few companies that have found thorium resource at their projects in Australia include Arafura Resources (FWB:REB), Northern Minerals (ASX:NTU), Capital Mining (ASX:CMY) and Lynas Corporation (ASX:LYC).
Back in the beginning of April 2016, thorium deposits were "accidentally" found by the Geological Survey in India's Bayyaram of Khammam district.
Editor's note: This is an updated version of an article previously published on August 15, 2015.
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