In their search for a method of achieving practical nuclear fusion, European scientists announced that they had made a major breakthrough.
The Joint European Torus (JET) laboratory in the United Kingdom has beaten its own world record for the amount of energy it can extract by joining two forms of hydrogen.
If nuclear fusion -similar to the one that occurs in stars – can be successfully recreated on Earth, offers the potential for virtually unlimited supplies of low-carbon, low-radiation energy.
The experiments produced 60 megajoules of energy for five seconds (11 megawatts of power).
This is more than double what was achieved in tests similar in 1997.
It is not a production ion of massive energy, just enough to boil around 52 water kettles. But the importance is that it validates the design choices that have been made for an even larger fusion reactor now being built in France, the International Thermonuclear Experimental Reactor (International Thermonuclear Experimental Reactor), known by its acronym ITER.
“The JET experiments brought us one step closer to fusion energy”, he said Dr. Joe Milnes, Head of Reactor Laboratory Operations.
“We have shown that we can create a ministar inside our machine and hold it for five seconds and get high output, which really takes us to a new scenario”.
The ITER complex in the south of France is supported by a consortium of world governments, including member states of the European Union, United States, China and Russia.
It is expected to be the last step to de show that nuclear fusion can become a reliable source of energy in the second half of this century.
This has advantages, since operating the power plants of the future based on fusion would not produce greenhouse gases and also generates very small amounts of short-lived radioactive waste.
“ These experiments that we just completed had to work,” said JET Executive Director Professor Ian Chapman. “If they hadn’t, we would have real concerns about whether ITER could meet its objectives,” he added.
“There were a lot is at stake and the fact that we have achieved what we did was due to the brilliance of the people and their confidence in the scientific effort”, the professor told the BBC.
The solution found
Fusion works according to the principle that energy can be released by forcing the union of the atomic nuclei rather than splitting them, as in the case of fission reactions that drive existing nuclear power plants.
In the core of the Sun, enormous gravitational pressures allow this to happen at temperatures around 10 million degrees centigrade.
At much lower pressures than are possible to recreate on Earth, the temperatures to produce fusion must be much higher, above 100 million degrees centigrade.
There are no materials that can withstand direct contact with such heat.
So, to achieve fusion in a laboratory, scientists have devised a solution in which a superheated gas, or plasma, is held within a donut-shaped magnetic field .
The JET, located in the south of England, has been pioneering this fusion approach for almost 52 years. And during the last years, has been configured to replicate the expected ITER installation.
Will it help the fight to save the planet?
Analysis by Roger Harrabin, media expert environment
The announcement of the merger is great news, but unfortunately it will not help in our battle to reduce the effects of climate change.
There is great uncertainty about when fusion energy will be ready for commercialization. One estimate suggests that perhaps in 10 years. Then fusion would have to be extended, which would mean a delay of perhaps a few more decades.
And here is the problem: the need for carbon-free energy is urgent.
In the words of my colleague Jon Amos: “Merger is not a solution to get us to zero emissions for 2025. This is a solution to boost society in the second half of this century”.
The preferred “fuel” of the French laboratory to make the plasma it will be a mixture of two forms -or isotopes- of hydrogen called deuterium and tritium.
JET was required to demonstrate a coating for the Container of 80 cubic meters that encloses the magnetic field that would work efficiently with these isotopes.
For your unprecedented experiments in 946, JET had used carbon, but the carbon absorbs tritium, which is radioactive. So, for the last tests, new walls for the container were built with beryllium and tungsten, which are two metals and which are 10 times less absorbent.
Next, the JET science team had to adjust their plasma to work effectively in this new environment.
“This is a surprising result because they were able to demonstrate the largest amount of energy output from fusion reactions of any device in history,” commented Dr. Arthur Turrell, author of a book titled in English “The builders of stars”.
“It is a milestone because they demonstrated the stability of the plasma for five seconds. That doesn’t sound very long, but on a nuclear time scale, is a very, very long time. And it’s very easy to go from five seconds to five minutes, or five hours. , or even more”.
The food problem
JET can no longer function because its copper electromagnets get too hot.
For ITER, internally cooled superconducting magnets will be used.
It is well known that fusion reactions in the laboratory consume more energy to start than they can produce. In the JET, two flywheels of are used megawatts to run the experiments.
But there is strong evidence that this shortfall can be overcome in the future as plasmas expand.
The volume of ITER’s toroidal vessel will be 10 times greater than that of JET. And the French laboratory is expected to break even. The commercial power plants that follow should have a net profit that could feed the electricity grids.
This is a long-term challenge and it is significant that, of the approximately 300 scientists working at JET, a quarter are in the early stages of their careers. They will have to carry out the investigation.
“ Fusion is time consuming, complex, difficult,” said Dr. Athina Kappatou. You still have less than 11 years.
“That is why we have to make sure that, from one generation the next, there are scientists, engineers and technical personnel who can get things done”.
However, there are still many technical challenges.
In Europe, the Eurofusion consortium , which includes about 5. science and engineering experts from across the European Union, Switzerland and Ukraine, is working in these challenges.
The United Kingdom is also a participant, but has faced problems due to its exit from the European bloc after Brexit.
Still, things are already moving forward.
JET is likely to be terminated after 1997 and that ITER begin plasma experiments at 2025, or shortly after.
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