Nuclear fusion is considered a clean and almost inexhaustible source of energy. But so far nobody has succeeded in using it. Because this was previously considered extremely complicated. However, a British company is pursuing a comparatively simple approach – and is achieving initial successes with it.
Fossil fuels such as oil, gas and coal have made mankind addicted to them, but the side effects are ruinous: climate change, environmental pollution and inhumane oil dictatorships. A clean and inexhaustible source of energy would be the solution. Nuclear fusion is considered a hot candidate. It is the same process that also releases energy in stars like the sun. So far, however, nuclear fusion has only been realized on earth in nuclear weapon tests and in experimental reactors – until now, mankind seemed far removed from peaceful use. Ironically, a small cancer could now bring the breakthrough.
So far, the problem with nuclear fusion is that it is quite complicated to run it in a controlled manner. In order to produce them artificially, enormous temperatures of up to 100 million degrees Celsius are required. For a long time, the so-called tokamak was considered the most promising approach for a fusion reactor: In the design first implemented in Russia in the 1950s, hot gas is held together with strong magnets and made to fuse. A huge tokamak is currently being built in southern France: the international experimental reactor ITER.
ITER is a huge machine – because these types of tokamaks can only produce more energy than they consume if they are of a certain size. ITER aims to prove that fusion power plants are possible. But whether it will ultimately be an affordable concept remains to be seen. Experts also do not expect that the first real fusion power plant can be expected before 2050. In the meantime, however, small companies with leaner merger approaches are trying to push their way past ITER. Some of them rely on less researched concepts, but promise quick success. One company has recently caused a stir: First Light Fusion from England.
And this is where the aforementioned cancer comes into play. Because the developers at First Light Fusion were inspired in their fusion reactor by a principle that can be observed in crackers. With a quick movement of their scissors, the animals can create a small bubble in the water, which implodes shortly afterwards. This creates a flash of light and temperatures of several thousand degrees. The crabs use this to catch prey, among other things. First Light, on the other hand, wants to implode a small amount of hydrogen in this way. Thanks to what is known as inertial fusion, the atomic nuclei then fuse and release energy. Much energy. Fusion fuel contains about ten million times the energy of the same mass of coal, oil or gas.
And this is how the concept works: Small cubes filled with some hydrogen are dropped into a reactor and shot at from above with a projectile. If the bullet hits the cube in free fall, the small hydrogen bubble inside is crushed by the force of the impact. The pressure on them is higher than in the center of the planet Jupiter. The hydrogen fuses, like a drop of gasoline injected into a combustion chamber and ignited. The process is repeated every 30 seconds. The released energy is absorbed by liquid lithium, which rains down all around – at least that’s the theory.
The lithium curtain not only absorbs the heat of fusion, it also traps the neutrons that are produced. An extremely ingenious trick: Because these fast particles are one of the biggest problems with other reactor concepts such as the tokamak, because they attack the material. However, First Light’s design makes the neutrons usable, because the bombardment turns lithium into tritium, the type of hydrogen that is needed for fusion. “The appeal of our approach lies in the fact that it circumvents some of the most difficult problems in fusion technology,” Gianluca Pisanello told ntv.de. The former Formula 1 engineer is Chief Operating Officer of the company, which was founded in 2011 by Nick Hawker and Yiannis Ventikos as a spin-out from the University of Oxford.
While the front end of their power plant concept appears futuristic, the rear end is based on the well-known: the heated lithium transfers its energy to water, which evaporates and drives a turbine that produces electricity. Exactly the same as in previous coal, gas and nuclear power plants. However, nuclear fusion does not produce greenhouse gases or long-lived nuclear waste.
It all sounds well and good – but does it actually work? At the beginning of April, First Light was able to book a partial success. During experiments, the researchers succeeded in fusion for the first time. Atomic nuclei of the hydrogen isotope deuterium were fused together. However, deuterium is later to be fused with tritium for successful energy production. The successful experiment was monitored and confirmed by observers from the British atomic energy organization UKAEA.
But in order for this concept to actually be implemented as a reactor, the nuclear fusion generated must emit more energy than is put into operation. This is the holy grail of fusion research – unmatched until now. “We have set ourselves the goal of achieving this within this decade,” said Pisanello. A corresponding demonstration reactor, which is intended to generate energy, is already being developed at First Light.
If it can be proven experimentally that energy can be generated, says Pisanello, the rest will remain a purely technical challenge. However, many of the necessary technologies already existed. If all goes well, the first power plant with an output of 150 megawatts should be built in the 2030s – about as much as the largest solar parks in Germany today can deliver. At the same time, the reactor should cost less than a billion dollars. The gigantic ITER, for example, is expected to cost 22 billion dollars with a targeted output of almost 500 megawatts.
First Light hopes to eventually be able to produce electricity at a price of $50 per megawatt hour – half the price of today’s coal-fired power and about the same as wind and solar power. But unlike these, a fusion power plant is not dependent on the weather or the time of day.
The British company’s plans sound promising. But First Light is not without competition: According to the Fusion Industry Association (FIA), there are now more than 30 private companies worldwide that want to tap nuclear fusion as an energy source. The approaches are quite different. The Canadian company General Fusion, for example, relies on the concept of magnetized target fusion (MTF), in which a hollow, rotating sphere made of liquid metal is suddenly compressed. In the core, hydrogen is to be compressed so much that it fuses at 100 million degrees Celsius.
Commonwealth Fusion Systems from the USA relies on the well-known tokamak principle. However, their reactor should be significantly more compact than ITER. High-performance magnets that also work at higher temperatures should make it possible. The US company TAE Technologies, on the other hand, relies on inertial fusion, like First Light Fusion, but without interfering neutrons. This is said to be achieved by boron-hydrogen fusion. The German company Marvel Fusion from Munich has the same fuel in its sights and wants to drive it to fusion with powerful lasers.
The desired time horizons sound similar for all companies – the first successful tests should take place in the middle of this decade, and the first reactors will be built in the 2030s. First Light sees an advantage in the fusion race: “We believe that our unique projectile fusion concept offers the fastest, easiest and most cost-effective route to commercial fusion power,” said Pisanello.
But even if nuclear fusion works, can it really be the solution to all energy worries? First Light Fusion sees nuclear fusion as at least a necessary part of a fossil-free world: “It is clear that wind and solar energy alone will not be able to meet the projected global demand and that there is a gap in clean energy will,” says Pisanello. “To close this gap, it is imperative that we continue to expand existing renewable energies and invest in new clean energy technologies such as nuclear fusion. This is what motivates us to achieve commercial fusion.”
(This article was first published on Sunday, May 22, 2022.)
