Fusion reactors could provide much more power than previously thought, study suggests

Written on 5/26/22

Scientists have revised a fundamental law “foundational” to fusion energy research that could allow for more hydrogen fuel in reactors, and potentially help obtain more energy from fusion than previously thought.

The study, published earlier this month in the journal Physical Review Letters, showed that an upcoming international megaproject can operate with twice the amount of hydrogen fuel, and thereby generate considerably more energy.

Nuclear fusion involves two atomic nuclei combining into one, thereby releasing enormous amounts of energy – a process that occurs every day naturally in the sun, whose warmth comes from hydrogen nuclei fusing into heavier helium atoms. Conventional nuclear power plants rely instead on fission, whereby a uranium atom is split with a neutron, releasing a large amount of energy in the form of heat and radiation.

The International Thermonuclear Experimental Reactor (ITER) is an upcoming fusion megaproject that aims to replicate the fusion processes of the sun to create energy on earth.

Researchers in the project, including those from the Swiss Plasma Center (SPC), say they aim to create high-temperature plasma – the fourth state of matter – that provides the right environment for fusion to occur.

Plasma is an ionised state of matter, similar to a gas, that is made up of positively charged nuclei and negatively charged electrons, and is almost a million times less dense than the air we breathe, scientists explain.

It is created by subjecting “the fusion fuel” – hydrogen atoms – to extremely high temperatures, about 10 times that of the core of the sun, and forcing electrons to separate from their atomic nuclei.

In fusion reactors, the process takes place inside a donut-shaped structure called a tokamak.

In the new study, scientists showed that the upcoming ITER tokamak can theoretically operate with twice the amount of hydrogen and therefore generate more fusion energy than previously thought.

“In order to create plasma for fusion, you have to consider three things: high temperature, high density of hydrogen fuel, and good confinement,” Paolo Ricci, a co-author of the study from the Swiss Plasma Center said in a statement.

“One of the limitations in making plasma inside a tokamak is the amount of hydrogen fuel you can inject into it,” Dr Ricci added.

Since the early days of fusion, scientists theorised that as the fuel density is increased at some point there would be “disruption”.

“Basically you totally lose the confinement, and plasma goes wherever. So in the eighties, people were trying to come up with some kind of law that could predict the maximum density of hydrogen that you can put inside a tokamak,” Dr Ricci explained.

This article first appeared on The Independent