Fusion Research

Super-lasers, cosmic rays and temperatures ten times hotter than our Sun's! What do all of these have in common?

They are all being used or generated on Earth to obtain what we call sustainable energy.

Fusion research aims to reduce or eliminate radioactive and toxic wastes, as well as greenhouse gas emissions. The wastes and gaseous emissions are already significantly lower when compared to other methods of generating energy, such as fission facilities, especially when we include the commissioning and decommissioning of fission power plants. We still need to manufacture the materials required to construct fusion power facilities.

Current fusion research also looks at the metal alloys needed, in order to avoid the need to extract rare earth minerals. Stainless steel, lithium and ceramics are all considered abundant on Earth and easy to mine and are frequently used in fusion power plants.

What is plasma and fusion research?

Plasma research refers to the study of the fourth state of matter. It is a gas, but unlike other gases, plasma consists of ions and electrons that are only "bound" together by electrostatic forces. This makes plasma highly conductive, enabling it to interact strongly with magnetic fields.

Fusion research refers to the efforts done by scientists to investigate ways to harness atomic fusion energy for use on Earth. This research is complex because it requires creating a plasma with extremely high temperatures and pressures.

Nuclear fusion represents one of the densest energy sources that we have discovered how to tap into.

The atomic nuclei usually used in fusion are two "species" of hydrogen (H), called isotopes, namely deuterium and tritium. They are also called hydrogen-2 and hydrogen-3.

Fusion energy is defined as high-energy density because a lot of power can be produced and measured in the form of:

• megajoules per kilogram (MJ/kg);

• then be turned into heat or electricity, measured in megawatts - MW.

If we were to rank energy output, fusion comes on top, followed by fission, fossil fuel, hydrogen, biomass such as wood, and renewable energy sources such as tidal, at the end.

Cold fusion research

Traditional nuclear fusion requires incredibly high temperatures. In cold fusion, on the other hand, atoms are combined at much lower temperatures. Less high-energy radiation is given off, making this a safer fusion option.

The materials required for cold fusion research include:

• palladium (Pd) and nickel (Ni) metals

• electric coils or cells

• hydrogen isotopes

Cold fusion, as a concept, is not dissimilar to another method which has been scientifically proven but cannot efficiently be maintained for prolonged periods at the moment: muon-catalysed fusion. Muons are injected into a target material, even an atom, where they can then facilitate the fusion of atomic nuclei. This can happen at room temperature or even lower temperatures.

The current state of fusion power research

The current state of fusion power research is influenced by the examples that we were able to obtain from space and nature. What we do on Earth matches the processes we observe inside our Sun, which fuses hydrogen into helium.

Nuclear fusion commonly happens in stars and produces immense amounts of energy, which helps to keep the star burning for billions of years. Nuclear fusion can also be used to create nuclear weapons.

Currently, there are two "environments" in which fusion and plasma research can be put into practice:

• Inertia chambers: laser beams and x-rays are focused to heat a tiny pellet containing hydrogen fuel mixture (mostly deuterium and tritium) in gaseous, liquid or even solid (ice) forms. Then, the pellet gets ignited.

• Magnetic containment chambers: electromagnets are used to generate an electromagnetic field by running a current through them. The hydrogen gas contained in these vacuum chambers is then controlled or suspended by the electromagnetic field. The chamber is also heated by other means, all to allow deuterium and tritium to collide, fuse into helium, and release the energy we want to harvest.

The progress of nuclear fusion research

Fusion and plasma research progress has been made concerning plasma physics, material research and waste disposal, as well as energy containment and generation. Even the metals used for the inner and outer chambers are usually alloys formulated with improved mechanical and thermal properties.

However, the progress of nuclear fusion energy generation has been considered relatively slow over the years. The most recent breakthrough in fusion energy generated was made in 2022 at JET, as mentioned above. The previous record was achieved in 1995, so you can see that progress takes time.

The researchers' main intention is to achieve more energy from the fusion process than we put into running it. We now use more electricity and other resources to create the ideal conditions for fusion to happen than we can catch from the fusion reaction, and use.

If successful, it will be the "greenest" energy form our society will have. It might take a while until it becomes commercially viable, even after the breakthrough.

ITER project

ITER project is the world's largest fusion facility and fusion and plasma scientific research project. It is located underground in France. Its name stands for International Thermonuclear Experimental Reactor, but the abbreviation also means something in Latin: "the way", to be more specific.

Governments wish to see this reactor operational and capable of producing significant amounts of energy in only a few years, possibly by 2025, but whether that is possible remains to be seen.

ITER's type of toroidal reactor is also known as a tokamak.

It is important to mention that ITER is still under construction where it is located, in the commune Saint-Paul-lès-Durance. The ITER Tokamak complex consists of ITER itself and several other buildings and facilities necessary for operation, maintenance and safety. ITER will produce 500 MW of power during its 40-second experimental campaign by using < 50 MW of input power to heat up the plasma to fusion conditions. This will be the first time a machine has produced net power from the fusion process.

Now onto a few interesting details!

Nuclear fusion is a powerful force that can be used for energy generation, and it holds the potential to change the world as we know it. Plasma and fusion processes will continue to be researched for years to come.