While it has been around since the s and an experimental 10MW LFTR did run for five years during the s at Oak Ridge National Laboratory in the US, though using uranium and plutonium as fuel it is still a next generation nuclear technology — theoretical. Like all nuclear power production they rely on extensive taxpayer subsidies; the only difference is that with thorium and other breeder reactors these are of an order of magnitude greater, which is why no government has ever continued their funding.
China's development will persist until it experiences the ongoing major technical hurdles the rest of the nuclear club have discovered, he says. Others see thorium as a smokescreen to perpetuate the status quo: the world's only operating thorium reactor — India's Kakrapar-1 — is actually a converted PWR, for example. In his reading, thorium is merely a way of deflecting attention and criticism from the dangers of the uranium fuel cycle and excusing the pumping of more money into the industry.
And yet the nuclear industry itself is also sceptical, with none of the big players backing what should be — in PR terms and in a post-Fukushima world — its radioactive holy grail: safe reactors producing more energy for less and cheaper fuel. In fact, a National Nuclear Laboratory NNL report PDF concluded the thorium fuel cycle 'does not currently have a role to play in the UK context [and] is likely to have only a limited role internationally for some years ahead' — in short, it concluded, the claims for thorium were 'overstated'.
But even were its commercial viability established, given 's soaring greenhouse gas levels, thorium is one magic bullet that is years off target. Those who support renewables say they will have come so far in cost and efficiency terms by the time the technology is perfected and upscaled that thorium reactors will already be uneconomic.
Of course, that level of energy is exactly why we use nuclear energy — it is incredibly efficient as a source of power, and it creates very few emissions and carries a laudable safety record to boot. This conversation — "nuclear good but uranium dangerous" — regularly leads to a very good question: what about thorium?
Thorium sits two spots left of uranium on the periodic table, in the same row or series. Elements in the same series share characteristics. With uranium and thorium, the key similarity is that both can absorb neutrons and transmute into fissile elements.
That means thorium could be used to fuel nuclear reactors, just like uranium. And as proponents of the underdog fuel will happily tell you, thorium is more abundant in nature than uranium, is not fissile on its own which means reactions can be stopped when necessary , produces waste products that are less radioactive, and generates more energy per ton. So why on earth are we using uranium? As you may recall, research into the mechanization of nuclear reactions was initially driven not by the desire to make energy, but by the desire to make bombs.
And here we come to it: Thorium reactors do not produce plutonium, which is what you need to make a nuke. How ironic. The fact that thorium reactors could not produce fuel for nuclear weapons meant the better reactor fuel got short shrift, yet today we would love to be able to clearly differentiate a country's nuclear reactors from its weapons program.
In the post-Cold War world, is there any hope for thorium? Perhaps, but don't run to your broker just yet. Most naturally occurring uranium is U, but this common isotope does not undergo fission — which is the process whereby the nucleus splits and releases tremendous amounts of energy. By contrast, the less-prevalent U is fissile.
As such, to make reactor fuel we have to expend considerable energy enriching yellowcake, to boost its proportion of U Once in the reactor, U starts splitting and releasing high-energy neutrons. The U does not just sit idly by, however; it transmutes into other fissile elements. When an atom of U absorbs a neutron, it transmutes into short-lived U, which rapidly decays into neptunium and then into plutonium, that lovely, weaponizable byproduct.
When the U content burns down to 0. It has the potential to produce nuclear energy that is relatively safe and cheap, while also generating a much smaller amount of very long-lived radioactive waste than conventional reactors. Construction of the experimental thorium reactor in Wuwei, on the outskirts of the Gobi Desert, was due to be completed by the end of August — with trial runs scheduled for this month , according to the government of Gansu province.
Thorium is a weakly radioactive, silvery metal found naturally in rocks, and currently has little industrial use. It is a waste product of the growing rare-earth mining industry in China, and is therefore an attractive alternative to imported uranium, say researchers.
But the technology will take many decades to realize, so we need to start now, he adds. Operated by the Shanghai Institute of Applied Physics SINAP , the Wuwei reactor is designed to produce just 2 megawatts of thermal energy, which is only enough to power up to 1, homes.
But if the experiments are a success, China hopes to build a megawatt reactor by , which could power hundreds of thousands of homes. The naturally occurring isotope thorium cannot undergo fission, but when irradiated in a reactor, it absorbs neutrons to form uranium, which is a fissile material that generates heat. Thorium has been tested as a fuel in other types of nuclear reactor in countries including the United States, Germany and the United Kingdom, and is part of a nuclear programme in India.
But it has so far not proved cost effective because it is more expensive to extract than uranium and, unlike some naturally occurring isotopes of uranium, needs to be converted into a fissile material. Some researchers support thorium as a fuel because they say its waste products have less chance of being weaponized than do those of uranium, but others have argued that risks still exist. When China switches on its experimental reactor, it will be the first molten-salt reactor operating since , when US researchers at the Oak Ridge National Laboratory in Tennessee shut theirs down.
And it will be the first molten-salt reactor to be fuelled by thorium. Researchers who have collaborated with SINAP say the Chinese design copies that of Oak Ridge, but improves on it by calling on decades of innovation in manufacturing, materials and instrumentation.
Also, as noted earlier, thorium is not a fuel. There are several ways thorium could be applied to energy production. In fact, more than 20 reactors world-wide have been operated with fuel made of thorium and uranium Another prospect that has been exciting to scientists and nuclear power advocates is the molten salt reactor. In these plants, fuel is dissolved in liquid salt that also acts as the coolant for the reactor.
The salt has a high boiling point, so they can be more efficient in electricity generation and even huge temperature spikes will not lead to massive reactor accidents such as occurred at Fukushima. It might sound like this kind of reactor is almost the stuff of science fiction, but just such a reactor was operated in the United States in the s and is currently being built in the Gobi Desert in China.
Thorium was discovered by Jons Jakob Berzelius in , who named it after Thor, the Norse god of thunder. Sign up for our Newsletter! Mobile Newsletter banner close.
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