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The dream of clean and unlimited nuclear fusion energy, within reach?

2022-07-20T10:37:58.957Z


A joke says that this technology is an eternal promise of the future that always takes about 30 years to implement, but the latest ITER results allow us to be optimistic


The Sun has fueled life on earth for millions of years, producing light and heat through nuclear fusion.

With this amazing capacity and longevity, it seems that there can be no better method of generating energy than to mimic the nuclear processes that occur in our stars and those of other planetary systems.

The purpose of nuclear fusion reactors is to replicate this process by fusing hydrogen atoms in order to create helium and produce energy in the form of heat.

Sustaining this process over time and at the required scale would mean that it is possible to produce a safe, clean and almost inexhaustible source of energy.

More information

The biggest research project on Earth gets serious

The search began decades ago.

Now, however, could the joking comment that “nuclear fusion is always 30 years away from becoming a reality” start to get old?

Some experts hope so, motivated by the momentous scientific breakthrough achieved in a nuclear fusion experiment in late 2021. The achievement occurred at the Joint European Torus (JET) research facility in Oxfordshire, UK, on ​​a machine of gigantic dimensions and shaped like a donut called tokamak.

Inside, superheated gases called plasmas are generated, in which fusion reactions take place containing charged particles, which are held in place by powerful magnetic fields.

These plasmas can reach temperatures of 150 million degrees Celsius, which is immeasurable considering that the temperature at the center of the Sun is 10 times lower.

The energy that was generated lasted only five seconds, but the goal is to achieve a sustained reaction

With a reaction sustained for five seconds, EUROfusion consortium research staff released a record-breaking 59 megajoules (MJ) of fusion energy.

The figure, which is almost three times higher than the previous record of 21.7 MJ reached at the same facility in 1997, is considered "the clearest proof in the last 25 years of the ability of nuclear fusion to produce safe, sustainable energy. and low emissions.

Here you can find more information about the successful nuclear fusion experiment at JET.

The results have provided a strong impetus for the next phase of nuclear fusion development.

A more advanced and larger version of JET, known as ITER (which means "the road" in Latin), is under construction on an area of ​​180 hectares in Saint-Paul-lès-Durance, in the south of France.

The purpose of ITER, in whose construction 35 countries collaborate, including those of the EU, is to continue developing and specifying the concept of fusion.

The forecast was that this machine, one of the most complex ever built, would generate its first plasma in 2025 and be fully operational in 2035, but the project's research staff expect some delays due to the pandemic.

A momentous advance

The JET results represent a milestone, according to Professor Tonny Donné, program director of the EUROfusion project, a consortium bringing together 4,800 specialists, students and facilities from across Europe.

"It's a substantial advance, the biggest in a long time," he said.

"All the models have been confirmed and that has greatly increased our confidence that ITER will work and achieve its goal."

Since the energy that was generated in the JET lasted only a few seconds, the objective is to prolong this duration and achieve a reaction that produces energy in a sustained manner.

The results have been the culmination of years of preparation and, as Professor Donné explained, one of the key developments since 1997 has been the change of the inner wall of JET's chamber.

The wall used to be made of carbon, but it turned out to be too reactive to the mixture of deuterium and tritium, two heavier isotopes or forms of hydrogen used in the fusion reaction.

As a result, hydrocarbons were formed that isolated the tritium fuel in the wall.

In the refit, in which 16,000 components were retrofitted and more than 4,000 tons of metal used, carbon was replaced with beryllium and tungsten to reduce tritium retention.

In doing so, the team was able to significantly reduce the amount of trapped fuel, which contributed to the success of the recent fusion experiment.

A demo center

In preparation for the next phase of the epic fusion journey, changes to JET ensured that its configuration is consistent with ITER plans.

On a more distant horizon, the next step to ITER will be a demonstration plant, known as DEMO, which, after sending electricity to the electrical grid, will make fusion power plants a commercial and industrial reality.

"ITER can create 10 times more fusion energy than the energy required to heat the plasma," Professor Donné noted.

"But being an experimental facility, it will not feed electricity into the grid. For that we need a different piece of equipment, which we call DEMO. This will really bring us closer to the starting point of the first generation of fusion power plants."

Professor Donné continues: “JET has shown that fusion is feasible.

ITER has to prove that it is viable and DEMO must prove that the whole system really works”.

According to him, it is realistic to expect that the DEMO, which is intended to divert 500 megawatts (MW) to the electricity grid, will be launched around 2050. "We hope to apply what we have learned and build the DEMO faster than the ITER," he said.

However, there are other key challenges to overcome before nuclear fusion can take place in the ordinary way.

One of them is that, while deuterium is abundant in seawater, tritium is extremely scarce and difficult to produce.

Therefore, the research staff plans to develop a way to generate it in the tokamak, through "fertile modules" that contain lithium.

The underlying idea is that hyper-energetic neutrons from fusion reactions interact with lithium to create tritium.

an essential energy

Professor Donné says that nuclear fusion could be a crucial source of green and sustainable energy in the future.

"I would say it's essential," he declared.

“I am not convinced that before 2050 we can get rid of carbon dioxide using only renewable energy, so we need alternatives.”

And although he says that the current method of creating nuclear energy by fission is increasingly safe, fusion has very important advantages.

Those involved in the ITER program speak of benefits such as the absence of the risk of core meltdowns, adding that nuclear fusion does not produce persistent radioactive waste and that reactor materials can be recycled or reused for a period of 100 to 300 years. .

"Without a doubt, it's much safer," Donné said.

Referring to the stigma attached to nuclear power, Donné said, "What we see when we interact with the public is that very often they haven't heard of nuclear fusion, but when we explain the pros and cons, I think that people are much more favorable".

Asked about Lev Artsimovich, who has been dubbed “the father of the tokamak”, Donné says: “Artsimovich has always said that the merger would be there when society really needed it.

If we manage to start it up and make it operational, we will have a clean and very safe source of energy that will provide us with energy for thousands of years.”

The research described in this article has been financed with EU funds.

Article originally published in

Horizon

, the European Union Research and Innovation Magazine.

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Source: elparis

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