Nuclear fusion is always 30 years distant, according to the traditional joke. As we meet an ITER researcher to follow up on work at the reactor plant, the promise of abundant clean energy is no laughing matter.
The Sun has fuelled life on Earth for billions of years by producing light and heat through nuclear fusion. Given that amazing strength and durability, it appears that harnessing the same nuclear processes that occur in stars, including our own sun, is the only method to create energy.
Nuclear fusion reactors attempt to replicate this process by fusing hydrogen atoms to generate helium, which releases energy in the form of heat. Maintaining this on a broad scale has the potential to generate a safe, clean, nearly infinite power source.
The hunt began decades ago, but will the long-running joke that nuclear fusion is always 30 years away become outdated?
Some believe so, following a huge success during a nuclear-fusion experiment in late 2021. This occurred at the Joint European Torus (JET) research facility in Oxfordshire, UK, in a massive, doughnut-shaped machine known as a tokamak.
Inside, superheated gases called plasmas are created, which contain charged particles kept in place by high magnetic fields and are where the fusion events take place. These plasmas may reach temperatures of 150 million degrees Celsius, which is an inconceivable ten times hotter than the core of the Sun.
Researchers from the EUROfusion group unleashed 59 megajoules (MJ) of fusion energy in a continuous five-second burst. The results were hailed as "the clearest demonstration in a quarter of a century of the potential for fusion energy to deliver safe and sustainable low-carbon energy”, nearly tripling the previous 21.7 MJ record established at the same facility in 1997.
Follow the link to read more about JET's successful nuclear fusion experiment.
The findings are a significant step forward in the development of nuclear fusion. ITER (meaning "The Way" in Latin) is a larger and more advanced version of JET that is being built on a 180-hectare site in Saint-Paul-lès-Durance, southern France.
ITER is being created as a partnership between 35 nations, including those in the EU, with the goal of further solidifying the notion of fusion. One of the most complex machines ever built, it was supposed to start producing plasma in 2025 before entering high-power operation in 2035 - however researchers on the project foresee significant delays due to the epidemic.
Major milestone
The JET results are a significant milestone, according to Professor Tony Donné, program manager of the EUROfusion project, a large coalition of 4,800 professionals, students, and institutions from around Europe. “It’s a huge milestone – the biggest for a long time,” he remarked.
“It’s confirmed all the modeling, so it has really increased confidence that ITER will work and do what it’s meant to do.” While the energy produced at JET lasted just a few seconds, the goal is to gradually increase this to a sustained reaction that produces energy.
Prof Donné explained that one of the significant advancements since 1997 was modifying the inner wall of the JET vessel, and the results were the culmination of years of planning.
The wall was formerly built of carbon, but it proved too reactive with the fuel combination of deuterium and tritium, two heavier isotopes - or variations - of hydrogen utilized in the fusion reaction. This caused the creation of hydrocarbons, which trapped the tritium fuel in the wall.
To decrease tritium retention, the carbon in the refurbishment, which required 16 000 components and 4 000 tonnes of metal, was replaced with beryllium and tungsten. Finally, the team was able to significantly reduce the amount of trapped fuel, leading to the success of the recent fusion shot.
DEMO run
Upgrades to JET ensured that its configuration aligned with the plans for ITER in readiness for the next chapter of fusion's epic journey. Beyond ITER, the next phase will be a demonstration power plant known as DEMO, which will be intended to deliver energy into the grid, eventually leading to fusion reactors being a commercial and industrial reality.
“ITER is a device which will create 10 times more fusion energy than the energy used to heat the plasma,” Prof Donné explained. “But as it is an experimental facility, it will not deliver electricity to the grid. For that, we need another device, which we call DEMO. This will really bring us to the foundations for the first generation of fusion power plants.”
Prof Donné added: “JET has shown now that fusion is plausible. ITER has to show that it’s further feasible, and DEMO will need to demonstrate that it really works.”
He believes DEMO, which is expected to contribute up to 500 megawatts (MW) to the grid, will be operational around 2050. “We hope to build DEMO much faster than we built ITER, making (use of the) lessons learned,” he stated.
However, there are several major obstacles to overcome before nuclear fusion can be operational. Not to mention that, whereas deuterium is plentiful in saltwater, tritium is highly rare and difficult to create.
As a result, the researchers want to create it within the tokamak using a lithium-containing "breeding blanket." High-energy neutrons from fusion processes are thought to interact with lithium to produce tritium.
Essential energy
Prof. Donné believes nuclear fusion will be a critical green and sustainable energy source in the future. “I would say it’s essential,” he noted. “I’m not convinced that by 2050 we can make the carbon dioxide transition with only renewables, and we need other things.”
And, while he claims that the existing way of producing nuclear energy through fission is getting safer, he believes that fusion offers significant advantages. ITER supporters tout benefits such as the absence of meltdown danger, as well as the fact that nuclear fusion does not generate long-lived radioactive waste and that reactor parts may be refurbished or reused within 100 to 300 years.
“It’s definitely much safer,” Prof Donné stated. “What we see when we interact with the public is that people very often haven’t heard about nuclear fusion", he added, referring to the stigma associated with nuclear energy. But when we explain the pros and cons, then I think people get positive”.
Referring to Lev Artsimovich, dubbed the “father of the tokamak,” he said, “Artsimovich always said fusion will be there when society really needs it. If we get fusion up and running, then really we have a very safe and clean energy source which can give us energy for thousands of years.”
Research in this article was funded by the EU.
This article was originally published in Horizon, the EU Research & Innovation Magazine.
