Long-awaited breakthrough for fusion energy

Inside the fusion reactor JET, with superimposed pink plasma. Credit: UKAEA, UK Atomic Energy Authority

After twenty years of research and preparation, a major European investment in fusion energy has come to fruition. At a temperature of over 100 million degrees, the researchers at the JET fusion plant in Oxford, UK recently broke the record for the creation of fusion energy – and thus took a major step on the road to fusion as a clean and emission-free energy source for the future.

"These are very important results that show that we have a solid foundation to build on. The record confirms what we have predicted in our models, at the same time as it gives us new knowledge that we can benefit from in the future", says Pär Strand, professor at Chalmers, part of the research collaboration project Eurofusion, and with long experience of fusion energy research.

The model for fusion energy is the sun, where large amounts of energy are released when light atoms join and form a new atom through fusion. But to bring about fusion on Earth, the atoms need to be heated to temperatures above 100 million degrees and controlled for a sufficiently long time. No materials can withstand such temperatures, so the resarchers at JET instead uses magnetic fields instead to keep the super heated gas – called plasma – in place in the reactor. The technology has been developed for a long time and now follows a clearly defined path to create clean energy on a large scale.

The record result was presented at an international press conference on February 9, 2022.

In the current experiment, 0.17 milligrams of fuel was used to create 59 megajoules of energy. In comparison, fossil fuels would have required 10 million times more fuel to generate the same amount of energy (1.06 kg of natural gas or 3.9 kg of lignite coal). This comparison highlights the power of the fusion reaction.

European research network behind the record

The researchers in Fusion Plasma Physics at the Department of Space, Earth and Energy at Chalmers are part of a network of 4,800 people at 150 universities and companies working with fusion. At Chalmers, the focus is on the theoretical part of the research, working on modeling and simulation of fusion plasmas. The record experiment was the result of a long effort in which researchers have rebuilt the JET reactor to be able to handle the plasma form of the fuel. The fuel is called DT after the hydrogen isotopes deuterium and tritium, and it is the same fuel that will be used in the next generations of reactors, next to the ITER reactor, which is currently being built in France which with its superconducting magnetic systems does not have the same limitations as JET.

"We have been able to learn a lot about how DT plasmas work and what the conditions in the reactor will look like during the merger. We can benefit from this for future experiments at ITER," says Pär Strand.

"For Swedish fusion research, this is important, not only for the researchers who have been directly involved in the experiments. The availability of unique new results means that we can test and validate models and tools in new parameter areas, which is very relevant for the research and development we do in collaboration with the organization around ITER."

Jet reactor interior detail. — The Jet reactor is located in Culham, England.

The technology is ready to be scaled up

The amount of heat energy produced in the experiment - 59 Megajoules - is not the most important part, but rather that the reactor kept a steady and high energy level for the five seconds it was designed for. So in terms of research, the scientific goal of JET has been achieved and the technology will be scaled up in the much larger facility ITER, which is currently being constructed in the south of France, with the goal of demonstrating the net effect of plasma.

"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. This is a big moment for every one of us and the entire fusion community. Crucially, the operational experience we’ve gained under realistic conditions gives us great confidence for the next stage", says Tony Donné, CEO of the international research program EUROfusion, the coordinated European investment in fusion energy .

After ITER, the plan is to build the even larger EU DEMO reactor, the last in a series of planned research facilities. DEMO will supply energy to the electricity grid and prove that fusion energy can be created in commercially viable quantities. It is planned to be ready after 2050.

"It is easy to become impatient, but we must take one step at a time on the roadmap that is set out to have a safe and efficient way of dealing with the global energy crisis. At the same time, parts of the development are progressing rapidly. For example, the capacity of the magnetic field that holds the plasma in place has tripled. Both are good for DEMO, although the efficiency of a reactor does not depend on the capacity of the magnetic field."