New Breakthrough in Nuclear Fusion - Is the End Near for Coal and Gas?

Revolution in nuclear fusion: scientists set new long-term record. AddMeshCube – stock.adobe.com

For decades, scientists have been working to build nuclear fusion as a safe alternative to nuclear fission. The hope is that it could harness the power of the sun and, in turn, revolutionize energy production.

Coal, gas, and other fossil fuels would thereby become obsolete, and the areas currently needed for solar and wind power could be significantly reduced. However, the technology is still in its early stages.

World record in nuclear fusion in the “Tokamak”

The Tokamak is one of the most common fusion reactors. It features a toroidal design and uses strong magnetic fields to confine hot plasma in a vacuum and heat it to extremely high temperatures. The aim of such reactors is to replicate the conditions that occur in stars.

Nuclear fusion promises an almost inexhaustible source of energy, as it is based on hydrogen isotopes such as deuterium and tritium which can be obtained from seawater. Tokamaks are central to the international research project International Thermonuclear Experimental Reactor (ITER).

Like many comparable projects, it aims to demonstrate the technical and economic feasibility of fusion energy as a clean and sustainable energy source.

One such reactor, the Tungsten Environment in Steady-state Tokamak (WEST), is partly operated by the French Alternative Energies and Atomic Energy Commission (CEA).

Over a period of six minutes, researchers from the U.S. Department of Energy (DOE) and the Princeton Plasma Physics Laboratory (PPPL) managed to maintain a plasma temperature of 122 million degrees Fahrenheit (°F) with an energy input of 1.15 gigajoules. This represents 15 percent more energy and twice the density compared to the previous record.

“Wonderful results”

“We need a new energy source that should be continuously and permanently available,” explained Xavier Litaudon, a CEA scientist and chairman of the Coordination on International Challenges on Long duration Operation (CICLOP). Litaudon said the work of PPPL at WEST is an excellent example.

“These are wonderful results. We have reached a steady state, even though we are in a difficult environment due to the tungsten wall.” The CICLOP is part of the International Atomic Energy Agency (IAEA).

Researchers from PPPL, which has been cooperating with WEST for some time, used a novel approach to measure various properties of the plasma radiation. They used an X-ray machine specially modified for this purpose from the Swiss manufacturer DECTRIS.

“The responsible X-ray group has developed these instruments for Tokamaks and other Stellarators around the world,” emphasized Luis Delgado-Aparicio. He is the head of the PPPL Department for Advanced Projects and the leading scientist of the X-ray detector project.

Scientists use six main types of fusion reactors

Numerous projects around the world are engaging with nuclear fusion. Some of the concepts used today were described by Dänner and Knobloch as part of their work published in 1971 for the Munich-based Max Planck Institute for Plasma Physics.

They pursue different approaches but all are aimed at the same goal: a sustainable and above all safe power supply. Specifically, researchers use six main types of fusion reactors:

1.         Tokamak Reactors: this is the most widespread and researched reactor type. Tokamaks use strong magnetic fields to confine a plasma in a toroidal (ring-shaped) vessel. The best-known Tokamak is ITER.

2.         Stellarators: similar to Tokamaks, Stellarators use magnetic fields to confine the plasma, but with a different construction and arrangement of the magnetic coils, leading to a more complex, three-dimensional magnetic field structure. Stellarators potentially offer more stable plasma confinement than Tokamaks.

3.         Inertial Confinement Fusion (ICF): with this method, nuclear fuel is rapidly compressed and heated with high-power lasers or other radiation sources, triggering a fusion. The National Ignition Facility (NIF) in the US is a prominent example of an ICF reactor.

4.         Magnetized Target Fusion (MTF): this type combines elements of magnetic confinement and inertial confinement fusion. A plasma is initially magnetically confined and then compressed to achieve fusion.

5.         Reversed-Field Pinch (RFP): another approach for magnetic plasma confinement. Here, the plasma is confined in a way that the magnetic field is reversed, which can lead to more stable plasma confinement.

6.         Spherical Tokamak: a variation of the traditional Tokamak design where the torus vessel is more compact and nearly spherical, which can lead to more efficient plasma ratios.

Researchers are getting closer to their bigger goal with each new record

Research teams are continually developing all these projects further. So the “WEST” is merely the next stage of the original Tore Supra. Back then, the inside of the reactor consisted of graphite tiles and used carbon instead of the tungsten used today.

“The tungsten wall environment is much more challenging than using carbon,” says Delgado-Aparicio. “It’s simply the difference between trying to catch the kitten at home and trying to stroke the wildest lion.”

However, tungsten has the advantage of retaining much less fuel – a characteristic that would be unacceptable for large reactors.

While the new record-breaking six-minute mark is still far from operating a Tokamak continuously, it’s still an important step. With each new record, researchers are getting closer to their bigger goal. Once the reactor passes one threshold, the next one is not far off, and the same applies to the next one.

If they manage to maintain nuclear fusion for 24 hours, it could establish itself as the energy source of the future.

Sources: Own Research; Princeton Plasma Physics Laboratory; “Possible Types of the Fusion Reactor, Reactor Physics and Technical Problems in Its Development” (MPG.PuRe, 1971)

This article was published in cooperation with futurezone.de.