Scientists have come closer to nuclear fusion; understand how

Photo: Gretchen Ertl, CFS / MIT-PSFC, 2021

Much of the energy we know today comes from a combustion process, that is, an exothermic chemical reaction – transferred from the inside to the outside – that occurs between a fuel, presented in the form of a liquid, solid or gaseous substance, and an oxidizer, in the most often it is an oxygen gas.

In this process, fuels undergo oxidation, because they lose electrons and their Nox (oxidation number) increases. The oxidizer, which is oxygen, reduces, as it gains electrons and its Nox decreases. Therefore, they undergo a variation of redox (when the state of the atoms are changed) for the formation of products (energy in the form of heat).

This type of energy is present in cars, planes, trains, industries and endless things. she is responsible for about 85% of the world’s energy. The problem is that this type of energy that ‘burns’ releases in the atmosphere gases harmful to health and global warming, such as carbon dioxide (CO2), being one of the most responsible for the climate crisis.

In the search for new (clean) renewable energy sources, in addition to solar, wind, hydro and other energy, scientists are aiming at fusion energy — the same that occurs in the Sun and in the stars of. Yeah, they kind of want to put the sun in a box.

In a successful small experiment, scientists at the Massachusetts Institute of Technology (MIT) and startup Commonwealth Fusion Systems (CFS) developed a high-temperature superconducting electromagnet with the most powerful magnetic field ever created on Earth.

But so you can know how this will change our future. Let’s understand some points:

What is fusion energy?

Nuclear fusion, or fusion energy, does not exist commercially, only in the laboratory. As I have already mentioned, it is a type of chemical reaction that occurs in the stars of space, caused by isotopes of hydrogen – deuterium and tritium – atoms that have the same atomic number (number of protons). Due to the gravity of stars, these elements come close to join and fuse, releasing helium and neutron (energy).

This only happens because inside stars there is a very high gravity that attracts these atoms, as it needs a very large force to bring nuclei with the same charge together.

However, to see the ‘Sun Rise on Earth’, scientists need to do it another way, because this process requires very high temperatures (100 million degrees Celsius), something that would melt any solid material we know. Hence the need to develop an object that can withstand so much heat.

The SPARC project

The SPARC project, as it became known, began three years ago from a nuclear engineering class taught by Dennis Whyte, director of MIT’s Plasma Science and Fusion Center.

Normally, this is done using intense magnetic fields, meaning scientists use a type of ‘invisible bottle’ to contain the hot part, a gas called plasma composed of electrons and protons. Particles are controlled by magnetic fields, as they have an electrical charge, and a rounded device called a tokamak to contain them.

In a conventional tokamak, the section that crosses the plasma is shaped like the letter D. When the straight part of the D faces the side of the hole, this shape is called positive triangularity. When the cross-section of the plasma is inverted and the curved part of D is facing the orifice side, it is called negative triangularity.

The innovation of this project is precisely that the scientists used high temperature superconducting electromagnets, which allow a much stronger magnetic field in a smaller space, in other words, it can retain the plasma, producing more energy than it consumes.

CFS Chief Operating Officer Joy Joy Dunn, he said be thrilled with the result, as the team built a first-of-its-kind superconducting magnet. In addition to eagerly awaiting the production of the SPARC that should be completed in 2025.

Why is fusion energy important?

It is not new that scientists have tried countless ways to make nuclear energy possible. A nuclear power plant, for example, is the dream of many nations. The ambitious project ITER, which uses low-temperature superconductors, is being built in southern France and has the collaboration of more than 35 countries. The idea is to build the biggest Tokamak in the world. As the name says “iter”, from Latin, path or path – for the energy of the future.

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Fusion plants would be clean energy sources because they do not involve greenhouse gases, such as CO2. Nor emission of long-lived radioactive waste, such as nuclear fission that generates radioactive elements that can last thousands of years – and cause damage to health. As Maria Zuber, vice president of research at MIT and professor of geophysics at EA Griswold, said to press from MIT that the amount of energy available is what changes the game, in the case for fusion energy here, the fuel used comes from water. “And the Earth is full of water, we just need to know how to use it,” he said.

It would be exciting to have an almost unlimited energy source. It’s as if we had a knife and cheese in our hands – but it shouldn’t be that easy to reproduce the Sun.