There are two kinds of nuclear reactions, fission reactions, and fusion reactions. The former involve a breakdown of large atoms into smaller ones, and we get a considerable amount of energy from the difference between their bond energies. What we have in our nuclear power plants, is all fission where Uranium atom is broken down to smaller atoms with a massive release of energy. Fusion, on the other hand, is still in its infancy. It involves joining or fusing two atoms and getting a larger atom along with the conversion of a small amount of matter into heat energy. Since there is no matter -energy conversion in fission, it amounts to a lower amount of energy than the Fusion reaction that is considered to be the ultimate reaction in the universe since it is the primary fuel of the Sun and all the rest of the stars. Even though some of the countries have developed successful Hydrogen bombs that operate on an uncontrolled fusion reaction, we are still several years away from controlling it to create a sustainable power source.
The German engineers at the famous Max-Planck Institute have successfully managed to fire up a Fusion reactor, and they have joined the list of few organizations that have successfully been able to suspend the dangerous plasma in place, so it doesn’t come in contact with the equipment. The 53-feet long reactor that is designed just for experimental purposes took 19 years of hard work and a billion dollars to complete. The area of focus has been the superconducting magnets that keep the dangerous plasma in place. A huge 420 tons of superconducting electromagnets have been made especially for this experiment, and they need to be cooled to ~0K or -273.16-degree centigrade to work. So, massive cooling units were also put in place for the reaction.
Another main hurdle in the fusion reactor is the starting temperature. We know that fusion is the stuff of the stars, and it should be extremely hot. Just how hot are we talking about? The core of the Sun, for example, is burning at an unreal 15 million degree Celsius all the time. But, we don’t have to achieve that to make the reaction start. At a certain initiation temperature, the atoms of Hydrogen start getting excited and fuse with each other on their own forming heavier elements and releasing a lot of energy. After the temperature has been achieved, we need to use the superconducting magnets to hold the resulting plasma together and in place or it will become a disaster of considerable proportions if the plasma manages to come in contact with the walls of the equipment.
The German named their reactor “Stellarator” and in it, a one-milligram sample of Helium gas was heated to 1 million degree Celsius with the help of a 1.8-megawatt laser. At this temperature, the fusion reaction was started, and the Germans tweeted the amazing happening with Das Erste Plasma!!! or the first plasma!! Although Hydrogen is a much better choice for a fusion reactor due to its simplicity, Helium was used by Professor Thomas Klinger and his team since it is much easier to achieve Fusion with Helium. No power has yet been harvested from this nuclear reactor for the sole purpose of this reactor was to make the process of fusion easier to achieve.
As you probably understand that fusion reactors take a lot of energy due to the Lasers, cooling equipment and heavy electromagnets. To make a viable fusion reactor, we need to make the energy gained in the reactor greater than the energy consumed to sustain it. This historic achievement was done by the National Ignition Facility in US. Another competitor reactor named Tokamuk is under construction in France with a multinational consortium behind it. Instead of suspending the plasma, they have made an intriguing design of a doughnut-shaped reactor where the plasma will flow. But, due to numerous difficulties, the Tokamuk reactor hasn’t yet been able to perform an experiment. The Stellerator remains to be the only fusion reactor currently running successfully in Europe, but the field is still wide open as no one has been able to benefit from it. The future is definitely exciting!