Artificial Suns: Nuclear Fusion Energy in

the foreseeable Future?

TszFung Tsui Grade-10

In Sci-fi games and novels, the energy requirement for advanced civilizations is always unbelievably high. To rationalize such high-energy consumption, authors of sci-fi works often set up fictional energy sources so the background logic makes sense. For example, in the first person shooter (fps) game, Doom, there is a fictional energy source known as “Argent”. And in another sci-fi video game, Halo, they used “Pinch Fusion” as the energy source. The Difference of the two is that “Argent” is something completely imaginary, while “Pinch Fusion” is more like an advanced and idealistic development of Nuclear Fusion Energy. Fusion power, also known as nuclear fusion energy, is a more realistic and approachable energy source for human civilization.

Fusion power is a proposed method of generating electricity from the heat produced by nuclear fusion reactions. During fusion, two lighter nuclei combine to form a heavier nucleus (formed by electrically positive protons and electrically neutral neutrons, surrounded by a negative charged electron)[Figure .1], releasing energy at the same time.

An example of nuclear reaction in our daily life observation is the sun. The sun is a high temperature sphere of gas made up mostly of hydrogen where most of the gas is plasma, which is the fourth state of matter. The process of fusion in the sun is the conversion of hydrogen to helium. As shown in Figure 2, hydrogen collides with another hydrogen and one of the protons turns into a neutron as a positron is released.

This newly formed nucleus is known as a deuterium, a stable isotope of hydrogen. Then when another hydrogen collides with deuterium, gamma rays will be released and form a light helium isotope known as helium-3. And as a result, two helium-3 will fuse together, two hydrogens (protons) will be released, and a helium-4 is produced.

So how much energy can be obtained from the fusion reaction? To understand the enormous amount of energy that fusion reactions can produce, we will need to set up a comparison. For example, in a general fission reaction, where a neutron smashes into Uranium-235 and splits into few neutrons, Barium and Krypton. The sum of the masses of these fission fragments is less than the original mass. The mass lost (about 0.1% of the original mass) has been converted into energy according to the renowned equation of Einstein “E=mc2”.

The binding energy from fission reaction (energy needed to separate an Atomic nucleus into neutron and proton) is shown from U238 to Fe56 on the graph [Figure.3], where we see the tiny uplifting gradient in the graph from right to left. In contrast, the fusion reaction where we use the example of the sun mentioned in previous paragraphs, can produce energy represented by the almost vertical gradient from H1 to F56 as shown in the same graph left to right.

In order to achieve nuclear energy by fusing Deuterium and Tritium, we need to reach a merit figure for the product. According to the Lawson Criterion, a figure of merit used in nuclear fusion research, plasmas must meet three conditions for fusion to occur: reaching sufficient temperature, density, and time.

Countries like the United States and China are striving for sustainable fusion power technologies. Among all the facilities exploring fusion power, Lawrence Livermore National Laboratory (LLNL) is one of the most advanced and for the first time had a result where they had greater energy exported than imported. The facility used 192 lasers to import 2.05 megajoules of energy to a small gold cylinder filled with frozen pellets of the hydrogen isotopes deuterium and tritium.

Energy from the lasers causes the capsule to collapse to temperatures high enough where hydrogen isotopes fuse into helium, releasing additional energy and creating fusion reactions. Laboratory analysis showed that the reaction released was about 3.15 MJ of energy, which is about 54% more energy than went into the reaction and more than double the previous record of 1.3 MJ.

On the other hand, the HL-2M is a research Tokamak at the Southwest Institute of Physics in Chengdu, China. It was completed on November 26, 2019 and opened on December 4, 2020. HL-2M is now used in nuclear fusion research, in particular to study the extraction of heat from plasmas. A Tokamak is a device that creates a very strong magnetic field which is able to restrict high temperature plasma and allow it to flow through the shape of a ring.

The HL-2M tokamak reactor is currently the largest advanced tokamak device in China with the highest parameters. It is the country's next-generation advanced magnetic confinement nuclear fusion experimental research device. The device adopts an advanced structure and control method, the plasma volume is more than twice that of existing domestic devices, the plasma current capacity is increased to more than 2.5 megaamps, and the plasma ion temperature can reach 150 million degrees. This means it can achieve high density, high specific pressure, and high bootstrap current operation.

Fusion power offers a potential long-term energy source that uses abundant fuel supplies and does not produce greenhouse gasses or long-lived radioactive waste. Furthermore, it allows humanity to take a huge step forward in civilization advancement.

With the power of nuclear fusion, mankind will for the first time raise the tinder of civilization and set sail to the ocean of the vast universe.