In the modern age, electrical energy is a crucial resource which is needed for almost everything in our society. Because of this, we are constantly searching for efficient and cost effective methods of generating power. One form of power generation which seems promising in this regard would be fusion reactors, which would utilize the process of nuclear fusion to generate electrical energy.The process of nuclear fusion is relatively simple. When the atomic nuclei of two atoms which are lighter than iron collide at high enough speeds, they end up fusing together into one heavier atom, while also releasing a massive amount of energy in the process. The energy which is released is a result of the mass defect between the two atoms being fused and the newly formed bigger atom. This is known as nuclear energy. Nuclear fusion produces the most energy when lighter elements are used, which is why the majority of nuclear fusion reactions in the universe involve the fusion of hydrogen to create helium.There are several different methods of achieving hydrogen based nuclear fusion all involving different isotopes of hydrogen, such as deuterium (1 Proton, 1 Neutron) and tritium (1 Proton, 2 Neutrons), and resulting in either Helium-3 (2 Protons, 3 neutrons) or Helium-4 (2 Protons, 4 neutrons). But the most prominent method when discussing nuclear fusion reactors would be Deuterium-Tritium reactions. This involves the fusion of deuterium and tritium to form a Helium-4 atom and a neutron with a significant amount of kinetic energy. A fusion reactor would utilize this reaction to generate electrical energy in a way very similar to that of nuclear fission reactors. These high energy neutrons would be submerged in water, and thus there kinetic energy would be converted into thermal energy due to friction, producing heat which would be transferred by a water-cooling loop to a heat exchanger to make steam. The steam would then spin a turbine in order to produce useful electrical energy.On the surface, nuclear fusion seems like an amazing way to generate power. The energy output is really high, as just one gram of deuterium and tritium produces the same amount of energy as 12,000 kilograms of hard coal. The two fuel sources for nuclear fusion are deuterium (Which is plentifully available and easily extractable from seawater), and tritium, (Which is admittedly harder to find than deuterium but can be created via contact with lithium during a fusion reaction). Fusion is also environmentally friendly, as the only byproduct from the reaction would be helium, which is harmless unlike emissions from other power sources such as carbon dioxide. So why aren’t nuclear fusion reactors mainstream? The answer is efficiency and containment.Firstly, nuclear fusion is currently not efficient at all, as it takes more electrical energy input to initiate the process of nuclear fusion than what is received in electrical energy output. This is because atomic nuclei contain protons, which are positively charged and thus will repel each other if brought close enough to collide. Thus the only way to counteract this repulsion is to give the hydrogen atoms in the reactor enough kinetic energy to overcome the force of the repulsion. Since temperature is the average kinetic energy of an object’s molecules, it stands to reason that you would need to raise the temperature inside the reactor by a significant amount in order for the fusion reaction to work. Specifically, the required temperature would be 150 million degrees Celsius, which is hotter than the centre of the sun and thus requires a lot of electrical energy to set up (The sun is still able to undergo nuclear fusion due to the massive amount of pressure it exerts on its core, which brings the atoms closer together). This leads to the second major problem, which is containing the reaction. At temperatures that high, matter inside the reactor is turned into incredibly hot plasma, which if not properly contained, will destroy the reactor from the inside-out. Fusion is a promising but currently unobtainable goal for power generation. While scientists are working on ways to fix the two major issues of efficiency and containment, as of now nuclear fusion reactors are not mainstream because they are not a viable source of electrical energy.