What Students Should Know About Nuclear Fusion

What is nuclear fusion?

Nuclear fusion is the process that powers stars, including the Sun. In this type of nuclear fusion, the extreme heat generated by the star's massive core causes light atomic nuclei to merge and form heavier nuclei, releasing energy in the process. The constant fusion of nuclei happening in the Sun means that it has an infinite energy source, keeping the star-powered.

Scientists have been trying to replicate this process on Earth since the 1950s. The necessary environment for the nuclei to merge could be recreated using heat, but that would mean achieving a temperature of over 100 million degrees Celsius - seven times hotter than the Sun itself! Currently, there are two techniques for achieving nuclear fusion: magnetic confinement and inertial confinement.

A magnetic confinement reactor heats plasma inside a toroid -- a donut-shaped tube. This is the method used by the International Thermonuclear Experimental Reactor (ITER) in France, the world's biggest nuclear fusion experiment today.

Inertial confinement uses laser beams to heat fuel so quickly it implodes, reaching the necessary conditions for fusion and releasing energy -- the same process used in the hydrogen bomb, although with a much larger amount of fuel. The National Ignition Facility in the USA, home to one of the most powerful lasers in the world, uses this method in its experiments.

Many other experiments worldwide use these two methods, and while the ultimate goal of creating commercially viable nuclear fusion has not yet been achieved, recent advancements have put us closer to it.

Why does it matter?

The climate crisis has made clean energy one of the top priorities for researchers. Today, most of the world's power comes from fossil fuels -- oil, gas, and coal. While these processes have been well developed and are cheap, these sources are non-renewable, contribute significantly to climate change due to the emission of CO2, and are prone to accidents like gas leaks or millions of gallons of oil dumped into the ocean.

Nuclear fusion is an ambitious goal: it is, essentially, creating an artificial, controllable star on Earth. But such achievement would mean a limitless source of clean energy. Because seawater is rich in hydrogen, which would fuel the fusion reactors, a single glass of seawater could produce the same power as burning a barrel of oil -- and without any waste.

Clean energy, made accessible to all, would revolutionize economic growth, improve global health, and eliminate many of the harmful processes responsible for destroying the environment. This is why nuclear fusion needs to be seen not as a theoretical experiment but as a feasible solution to many of the world's most pressing issues.

European Collaboration

Thanks to a recent breakthrough, scientists at the UK-based JET laboratory have produced 59 megajoules of energy over a five-second pulse of 11 megawatts. The energy output isn't much, but it's more than double what experiments could produce in 1997. "If we can maintain fusion for five seconds, we can do it for five minutes and then five hours as we scale up our operations in future machines," says Tony Donné, manager of the research group. This breakthrough marks an important landmark in nuclear fusion and advances plans for a new, larger reactor under construction in France.

USA and Japan

Some scientists don't think nuclear fusion will be available for the market until the next century. But others have a much more optimistic outlook on the field and trust viable nuclear fusion can be achieved by 2050. In the USA, scientists have called for urgent investment from the public and private sector, believing the country can have an operating fusion plant between 2035 and 2040. On the other side of the Pacific, the Japanese government has launched a plan to support the domestic development of equipment necessary to generate power through fusion, expecting to have the first reactor prototype by 2040.

Australia and New Zealand

A partnership between Deakin University and HB11 Energy Holdings aims to develop new and more efficient fuels for laser fusion reactors in Australia. The researchers claim the current fusion rate achieved by experiments has been limited by inefficient fuel materials, hence taking the initiative to change the scenario and produce two new hydrogen storage nanomaterials, new synthesis technologies, and a functional nuclear power source.

Tokamak reactors, the type used in magnetic confinement, depend on the stable temperature of superconducting magnets to generate the magnetic field that contains the heated plasma. Scientists at the Victoria University of Wellington's Paihau-Robinson Research Institute, in New Zealand, have developed an early-warning system capable of detecting small fluctuations in the magnets' temperature in mere milliseconds. This technology is set to be integral to the success and stability of nuclear reactors worldwide.

China

In June 2021, China's Experimental Advanced Superconducting Tokamak (EAST) reactor reached continuous plasma for 101 seconds - or nearly two minutes. As of January 2022, the same reactor broke its own record, maintaining stable heated plasma for 1056 seconds, or 17.6 minutes -- nearly ten times longer than the result achieved seven months prior. This landmark represents a significant advancement in fusion technology and shows a promising outlook for the upcoming years of research.

Russia

Moscow was home to the world's first tokamak reactor in 1958. Fusion research received significant funding in the following decades, and new reactors operated in Russia. In 2021, a new tokamak reactor called T-15MD was launched, with the unique proposal of combining high power with compact size. The project will support the ITER program in France through complementary research and technology and will be the major fusion experiment in Russia over the next decade.

Outlook for the next decade

What was once the longest of long shots is now a real possibility. Recreating a star on Earth seemed like an impossible venture decades ago, but now, with massive funding coming from governments and the private sector, scientists are making significant advances in fusion research. Although Tony Donné believes that achieving commercial fusion in the next decade is a bit too optimistic, other specialists believe these projections are not so much a fixed promise but a necessary target that motivates progress. Regardless of timeline projections, it's undeniable that the global scientific community is committed to making nuclear fusion a reality and making headway to the ultimate goal!

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