The search for simple and cheap nuclear fusion is on, and these two strategies hold great promise.

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Nuclear fusion as we know it so far it’s not easy. Not cheap. Experimental reactors that use magnetic confinement, such as JET, which has been in operation in the United Kingdom since 1983, or ITER, currently under construction in the south of France, demonstrate this. And with the inertial confinement advocated by other organizations, such as the Lawrence Livermore National Laboratory in the United States, exactly the same thing happens.

The challenges faced by the two strategies used in nuclear fusion that are giving us the best results so far are titanic, but little by little both are being refined. and moving forward. However, these technologies are not the only ones that seek to fine-tune a reactor capable of emulating the mechanism that allows stars to obtain energy using the fuel they contain inside.

Despite its challenges, nuclear fusion holds great promise. So much so that, in fact, some private companies have been born with the intention of proposing new ways more efficient and economical to carry it out. The British First Light Fusion and the Australian HB11 Energy are two of those that seem to have developed the most interesting alternatives to conventional magnetic and inertial confinement, so it is worth taking a look at their proposals.

An original way to implement inertial confinement fusion

The strategy developed by First Light Fusion (FLF) is very ingenious. The inertial confinement used in the NIF experiment (National Ignition Facility) at the Lawrence Livermore National Laboratory uses a very small amount of fuel, in the form of a small ball of deuterium and tritium, to get it to implode suddenly concentrating on it the energy of a large number of high-power lasers.

In this way the fuel is condensed with tremendous violence so that the probability of the deuterium and tritium nuclei fusing is very high. However, nuclear fusion by inertial confinement faces two major challenges. The first of these is the need to achieve energy profitabilitywhich is the point at which we get more energy through fusion than we have invested in triggering it.

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And the second challenge requires finding a way to stabilize the reaction so that it can be sustained over time. FLF’s approach is different. And it is that what its engineers propose is to launch a tungsten projectile at a very high speed so that it collides with a deuterium capsule housed inside a vacuum chamber.

The speed at which the projectile travels is crucial because it must be high enough for the impact energy to cause the fuel capsule to implode suddenly.

The speed at which the projectile travels is crucial because it must be tall enough so that the energy of the impact causes the sudden implosion of the fuel capsule. Otherwise the fusion reaction between deuterium atoms, which is an isotope of hydrogen, would not take place. Additionally, this strategy requires the launch of a new projectile every 30 seconds to sustain the fusion reaction over time.

From here, very roughly, a heat exchanger is responsible for transporting part of the thermal energy generated by the fusion of the deuterium nuclei outside the chamber. There a turbine first and an alternator later allow obtaining electricity in a process similar to that which takes place in today’s nuclear fission plants.

According to FLF their proposal is up to 50% more efficient and much less complex from a technological point of view than nuclear fusion by conventional inertial confinement. In addition, this company claims to have successfully carried out a pilot test that has been supervised by the United Kingdom Atomic Energy Authority.

In any case, despite how interesting this project sounds, it is prudent to moderate the enthusiasm. The technology proposed by FLF is taking the first stepsand putting into practice everything that it promises, no matter how good it looks, which it does, can force its engineers to solve challenges that may not be as easy to tackle as this company seems to suggest.

HB11 proposes another ingenious approach to inertial confinement

The strategy that the Australian company HB11 Energy has devised takes as its starting point the inertial confinement that we have described above, the conventional one, but rethinks it with the purpose of addressing it in a simpler and more efficient, at least on paper. The most obvious difference between one technology and another is that while inertial confinement requires the use of a large number of high-power lasers, the HB11 reactor uses only two.

As we can guess, this design principle should reduce the cost and technological complexity of the reactor, as well as the energy that needs to be invested in the process to trigger the nuclear fusion reaction. The first laser hits a coil housed inside a metal sphere in order to generate a powerful magnetic cage that is responsible for confining the plasma.

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Next, a pulse emitted by the second high-power laser hits a capsule of boron and hydrogen, dramatically accelerating the atoms of this last chemical element and triggering the fusion of their nuclei. One of the strengths of this strategy is that in this process no radioactive chemical elements are involvedlike tritium.

The result of the fusion of boron and hydrogen nuclei are alpha particles, which are nothing more than ionized helium nuclei.

In addition, the result of the fusion of boron and hydrogen nuclei are alpha particles, which are nothing more than ionized helium nuclei, which, therefore, have been stripped of their electrons. For this reason they have acquired a positive charge and can be confined by the magnetic field generated by the first laser.

On the other hand, the electrical charge of helium nuclei can be neutralized and used to generate electricity without the need to use a turbine capable of transforming kinetic energy into mechanical energy, which is what is currently done in fission nuclear power plants.

Panel Hb11 03 Magneticconfinement

Another point in favor of this strategy: it does not generate highly active radioactive waste that is difficult to deal with because the fusion of boron and hydrogen nuclei does not trigger the emission of high energy neutronssomething that, however, does happen as a result of the fusion of deuterium and tritium nuclei inside the reactors that resort to magnetic confinement.

All of this sounds good. In fact, those responsible for HB11 Energy claim to have carried out very promising tests at the Institute of Laser Engineering of the University of Osaka, in Japan, in which, according to them, their proposal has proven to be profitable from an energy point of view. However, as when we have explored FLF technology, it is wisest not to take anything for granted. Both options are very promising, but still have much to prove beyond their theoretical feasibility.

Cover Image | pixabay

More information | First Light Fusion | HB11 Power

Nuclear fusion as we know it so far it’s not easy. Not cheap. Experimental reactors that use magnetic confinement, such…

Nuclear fusion as we know it so far it’s not easy. Not cheap. Experimental reactors that use magnetic confinement, such…

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