Nuclear fusion has been slipping through our fingers for years. Now, after the milestone reached by scientists at a laboratory in Livermore, California, who for the first time have achieved nuclear fusion with net energy gain, we should ask ourselves if it is really possible to solve humanity's energy problems with a clean and unlimited source of energy.
Nuclear fission and nuclear fusion: What is the difference?
Nuclear fusion is a process whereby two atomic nuclei get close enough to each other to fuse and form a heavier nucleus. In this way, energy is released.
For fuel, a fusion reactor uses deuterium and tritium, isotopes of hydrogen that can be obtained relatively easily.
Nuclear fission is the opposite process: it occurs when a heavy nucleus separates into smaller nuclei, releasing energy. This is the technology that we currently use in our nuclear power stations, with uranium as the fuel.
Is nuclear fusion really a clean energy?
The answer is yes, nuclear fusion is clean energy. In fact, according to José Manuel Perlado, Chairman of the "Guillermo Velarde" Nuclear Fusion Institute at the Polytechnic University of Madrid (UPM) and professor emeritus of Nuclear Physics, it has always been described as "safe, clean and inexhaustible".
- It is intrinsically safe because it requires an external source to maintain it. Nuclear fusion is a reaction that stops when the fuel supply is cut off.
- It is clean because it does not generate medium- and long-term radioactive waste. The waste is the result of neutron activation. So, "no harmful gases are produced and nuclear waste of very low activity is generated."
- Finally, it is undoubtedly true that it is inexhaustible. "In the case of deuterium, it is found in abundance in ocean water, and tritium is generated within the reactor itself from deuterium", the expert added.
If we compare renewable nuclear energy with other types of energy, we can see that this is a much more revolutionary source. As José Manuel Perlado explained, "it could produce a potentially unlimited supply of clean energy without generating dirty waste or any significant amount of carbon emissions."
“Energy resulting from nuclear fusion has always been described as safe, clean and inexhaustible”.
– José Manuel Perlado, Chairman of the "Guillermo Velarde" Institute of Nuclear Fusion at the Polytechnic University of Madrid (UPM)
Research and developments in nuclear fusion energy
Although we still have a lot to learn about this type of energy, in recent years there has been endless research. According to Pablo Teófilo León, Endesa's Manager of Technology and Nuclear Development, "currently there are two main lines of research: Fusion by magnetic confinement and fusion by inertial confinement."
Magnetic confinement is obtained by generating a very intense toroidal magnetic field (in the form of a doughnut), through external coils that carry an intense current. Hydrogen or deuterium gas is injected into this magnetic field and heated to high temperatures to ionise. This ionised gas is called plasma.
There are currently a number of designs for the structure of the magnetic field including tokamak, stellerator and spheromak. Tokamak is the technology used in the ITER project. Our manager of Technology and Nuclear Development says that in Spain, “the CIEMAT has a Stellerator research fusion reactor.
With regard to fusion by inertial confinement, lasers are used to make a few milligrams of hydrogen (deuterium and tritium) reach temperatures similar to those of the Sun. The laser deposits its energy in the outer layer of the capsule, which causes the fusion fuel to compress until it reaches the temperatures and densities required for the reaction to occur.
The most important milestone related to this type of confinement has been achieved by the Lawrence Livermore National Laboratory. In December 2022 they managed to generate 1.3 megajoules for a fraction of a second. This brought the strategy advocating inertial confinement one step closer to energy profitability.
Although this is promising, according to Pablo Teófilo León: “There is still a lot of uncertainty. We still need to create a system that produces energy consistently."
“There is still a lot of uncertainty. We still need to create a system that produces energy consistently”.
– Pablo Teófilo León, Endesa's Manager of Technology and Nuclear Development
The ITER project: Dreaming of imitating the Sun
The ITER (International Thermonuclear Experimental Reactor) is the result of an unprecedented global collaborative effort. It is the largest experimental facility in the world dedicated to nuclear fusion and has been designed to demonstrate the scientific and technological feasibility of this type of energy. Technically, ITER's goal is to produce 500 MW of power for several seconds with "only" 50 MW needed to achieve that reaction.
El The ITER Project, which is sponsored by the IAEA (International Atomic Energy Agency) - is an international project that is looking to recreate for industrial purposes the physical processes that make the sun such a formidable source of energy. If it works, for the first time in history we will be able to produce a new form of abundant, constant and reasonably clean energy. However, reaching that goal will be a challenge equal to the reward.
At the heart of ITER, there is a Tokamak-type reactor, already mentioned above, which is also the largest that humanity has built to date. With regard to these challenges, the main milestones established by ITER are to obtain the first plasma in 2025 and to complete the first operations with deuterium and tritium by 2035.
If ITER is successful, the development of a demonstration nuclear fusion reactor (called DEMO) can be launched. Based on the experience achieved with the DEMO, it is assumed that the first industrial prototype could be ready by 2060. So the first commercial nuclear fusion reactor could be built before the end of this century.
So fusion, with the ITER project in the lead, appears to be an ideal candidate to become a safe, powerful and environmentally acceptable source of energy for the mass generation of electricity.
However, as we already stated at the beginning of the article, although it will still take years for this to become a true reality, progress and discoveries are constantly being made. In fact, the European Space Agency has discovered an exoplanet with a core in constant nuclear fusion.