One letter can change everything. A big announcement was made this week about nuclear fusion which has been received with jubilation for being a first step in the development of a new way of obtaining energy. However, with the announcement we could have a doubt. Don’t there already exist nuclear power plants? And isn’t it carrying something known as nuclear fusion?
It is not an unreasonable doubt, because in reality what is produced in these nuclear power plants has a very similar name: Nuclear fision. However, even though there is only one letter difference, they are practically opposite concepts And they have many differences.
To begin with, nuclear fission consists of separate the nucleus of a heavy atom in others lighter. Instead, fusion proceeds with the opposite process: the nuclei of two light atoms they merge, to give rise to a heavier one. This is a process in which, if certain conditions are met, a large amount of energy is obtained. So much so that it is precisely the way the Sun and other stars have to stay lit. The problem is that it is not easy to reproduce here on Earth. That is why the announcement made these days has been so important, since for the first time more energy has been obtained than had been invested in the process. This raises the possibility of taking advantage of that energy in the future, as with the Nuclear fision. Now, what other differences are there?
Differences between nuclear fusion and nuclear fission
We have already seen that the process is completely the opposite. In other words, nuclear fusion consists of uniting and fission consists of separating. But that is not all.
Nuclear fission occurs through a chain reaction, so that it is very difficult to stop it in the event of a fault that endangers the facilities. On the other hand, with nuclear fusion, as soon as the fuel is no longer supplied or breaks into emptiness in which the reaction is carried out, it stops completely.
On the other hand, with nuclear fission both the reactants and the waste are very radioactive. As a consequence, in the event of leaks caused by accidents such as Fukushima or Chernobyl, it would pose a great danger that would also remain for millions of years.
With nuclear fusion, two isotopes of hydrogen, known as tritium and deuterium, are generally used as fuel. These fuse their nuclei to give rise to a helium atom and a leftover neutron. Tritium is reactive, but it is not a problem, because it is consumed in the reaction. As for helium, it is totally harmless. For this reason, nuclear fusion is presented as a form of clean and safe energy. The truth is that it is clean, because does not cause carbon dioxide emissionssuch as fossil fuels. In reality, nuclear fission does not generate these emissions either. Regarding safety, it is true that nuclear fusion is safer than fission. But here a clarification must be made, since it is often said that it is because it does not generate radioactive waste and that is not entirely true.
As he explained to hypertextual Rafael Juarez Manasa professor of energy engineering at UNED and an expert in nuclear fusion, will be totally safe if the reactors are designed well. “There is waste and it is radioactive, but they are like those of a hospital”, he points out. “A hospital also has radioactive waste and it has no point of comparison with fission.” In addition, the time during which these residues are dangerous is very different from that of fission. “When you finish operating the plant, the reactor vessel is very considerable radioactive waste, you have to bury it and wait 100-200 years”, explains the expert. “You have to do it, but it has no point of comparison with a fission plant in which the fuel it takes millions of years to stop being dangerous”. This would be a very bad inheritance for possible civilizations or species that would totally escape our control.
Therefore, this is another of the differences between nuclear fission and fusion. In any case, today another big difference is that nuclear fission can already be used to obtain energy, with its lights and its shadows. The nuclear fusion, on the other hand, is still in its infancy. However, it has a lot of potential. We have already seen that what is expected of it is viable. We will have to continue working on it so that one day that difference ceases to exist.