Nuclear fusion is the future of this type of energy and, very probably, the only way for its persistence over time. But it is a complex technology that is not yet ready for large-scale use.
Amid the debate over whether the nuclear energy is the right path to decarbonization, scientists continue to work hard on a way to turn fusion into the relay that fission has been waiting decades for.
And it is that nuclear energy can be obtained in two ways. The Nuclear fision It is the one currently used and, broadly speaking, it consists of releasing energy through the separation of the nuclei of atoms to form smaller nuclei.
Nuclear fusion requires high levels of energy that allow nuclei to be brought together at very short distances.
Instead, the nuclear fusion It consists of the combination or fusion of the nuclei of atoms with each other to form a larger nucleus. That resulting core is lighter, but that mass loss is converted into a huge amount of energy.
Why nuclear fusion?
The key to the process of nuclear fusion is that does not generate direct radioactive waste. But what prevents its use today?
Essentially, nuclear fusion needs high levels of energy that allow nuclei to be approached at very short distances in which the forces of nuclear attraction exceed those of electrostatic repulsion.
Besides, keep plasma stable (the result of subjecting a gas to very high temperatures) is very complicated, since it is chaotic, its temperature is very high and it tends to suffer from turbulence and instability.
Tokamaks and stellarators
The key to the success of nuclear fusion is keeping this instability under control. To do this, scientists have devised magnetic confinement devices that make it possible: tokamaks and stellarators.
The tokamak it is an experimental facility, in the shape of a toroid, which generates and confines matter in its plasma state, applying both poloidal and toroidal magnetic fields; and a toroidal electric current on said plasma.
On the other hand the stellarator It is a thermonuclear magnetic confinement device consisting of a toric chamber, in which the poloidal and toroidal fields form highly braided current lines, created by external windings, and inside which the plasma is confined to obtain thermonuclear fusion.
Both types of reactors take advantage of the fact that charged particles react to magnetic forces. They keep the ions confined in the reactors thanks to powerful magnets. The electrons are also limited by the forces of the reactors and play a role in the vicinity. Magnetic forces are what continually spin the particles around the reactor chambers to prevent them from escaping from the plasma.
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At the moment, there are around 60 tokamaks and 10 stellarators in operation. This inequality is due to the fact that the latter are difficult to build. But both have certain advantages.
For one thing, the tokamak holds the heat of the plasma better. On the other hand, the stellarator is able to keep it more stable. The advances made in recent years, both at a theoretical, experimental, modeling and simulation level, make it possible to better understand the behavior of plasmas.
Therefore, the tokamak and the stellarator will be crucial to demonstrate the scientific feasibility and technique of fusion energy production.