Superconductor and Nuclear Fusion Breakthroughs Could Revolutionize Physics

The last week of July heralded not one but two scientific breakthroughs that have left the academic community abuzz and may bring us one step closer to the holy grail of fusion energy.

Nuclear fusion is a technology that creates energy in the same way as the sun. The process involves the smashing together of two atoms, which collide with such force that they combine into a single, larger atom, releasing large amounts of energy in the process.

Nuclear fusion offers a nearly limitless source of clean energy that does not produce carbon dioxide or other greenhouse gases. Unlike fission—the nuclear reaction that is used in the energy sector today—fusion does not produce radioactive water and involves no risk of nuclear meltdown due to the delicate nature of the reaction process.

Some have heralded it as the "holy grail" of energy production, but there is one problem: fusion requires vast amounts of energy to achieve due to the sky-high temperatures and pressures necessary for the reaction to take place.

The ratio between how much energy is put into a reaction versus how much comes out is called Q. In the past, Q has always been smaller than one, meaning more energy has been put into the reaction than has come out.

However, in December 2022, scientists at the Lawrence Livermore National Laboratory in California were able to achieve a net energy gain from a fusion reaction for the first time ever, getting more energy out of the reaction than they originally put it and achieving a Q greater than one.

On July 30, the lab repeated the experiment and achieved an even higher energy return than they had in December, according to a Lawrence Livermore spokesperson. However, the final results, and thus the value of Q, are still being analyzed.

Just three days before this breakthrough, researchers in South Korea announced another groundbreaking discovery: the world's first room-temperature superconductors.

But what does this have to do with fusion? To understand this, we need to take a step back and look at how nuclear fusion reactors actually work.

Research into nuclear fusion can be split into two branches: lasers and magnetic confinement. In both cases, the atoms involved are heated to super-high temperatures and confined in a small area, which forces them to fuse. The reactor at Lawrence Livermore uses an array of lasers to create these conditions. Magnetic confinement, meanwhile, uses powerful magnets to contain this super-hot mixture.

The mixture is called plasma and is basically a soup of negatively charged electrons and positively charged ions that have been ripped apart by the extremely hot temperatures of their surroundings. At these extreme temperatures—which are six times higher than the center of the sun—these ions begin to fuse, releasing energy in the process.

One company that is using this approach is called Tokamak Energy Ltd. The company uses a donut-shaped device called a spherical tokamak which houses these powerful magnets.

"Magnetic fields are used in a tokamak to confine and control plasma—the fusion fuel —allowing it to be heated to a temperature above 100 million degrees Celsius," David Kingham, executive vice chairman and co-founder at Tokamak Energy Ltd., told Newsweek. "Strong magnets enable more compact confinement, increasing plasma density and power."

These magnetic fields are generated by passing a large electric current through metal conductors. Today, the material used for the conductors is copper. However, conventional materials like copper have an electrical resistance that counteracts the flow of electricity and converts some of its energy into heat that is essentially wasted. This is where the superconductors come in.

"Superconductivity is an ability held by a select group of materials capable of carrying electrical currents with zero electrical resistance," Rod Bateman, magnets development manager at Tokamak Energy Ltd., told Newsweek. "These make for ideal electro-magnet conductors since they can carry the magnet current without overheating, which is crucial for power plant operations."

However, most superconductors today require extremely low temperatures to work their magic. "For most practical superconductors, this amazing property only works at very low temperatures, around -269 degrees Celsius, with limited magnetic fields," Bateman said.

"To maintain fusion conditions, a tokamak must withstand extreme temperature limits less than one meter apart—plasma temperatures hotter than the sun and cryogenic (freezing) temperatures for our superconducting magnets."

This is why there is so much excitement over the possibility of superconductors that can function at standard room temperatures.

The recent announcement from the Quantum Energy Research Center in Seoul describes a material called LK-99, made up of copper, lead, phosphorus and oxygen. According to the researchers, this material can act as a superconductor at temperatures over 126 degrees Celsius, 100 degrees higher than ambient room temperature.

However, the research has not yet been peer-reviewed and some scientists have expressed doubt over the properties of this material. The Condensed Matter Theory Center at the University of Maryland shared this message on X, formerly Twitter:

"With a great deal of sadness, we now believe that the game is over. LK-99 is NOT a superconductor, not even at room temperatures (or at very low temperatures). It is a very highly resistive poor quality material. Period. No point in fighting with the truth. Data have spoken."

Even if the results of the LK-99 study are confirmed, a lot more work needs to be done before this material can be used in a nuclear reactor at scale. "We look forward to learning more about the recent room temperature LK-99 results once verified, but there is some way to go before the technology could be useful for the fusion industry," Bateman said.

"For example, we would need to understand more about how the material can be manufactured at scale, cost and performance. Performance relates to if LK-99 has useful current densities at non-cryogenic temperatures in high background magnetic fields, and its resistance to neutron bombardment and levels of shielding required.

"The greatest challenge solved so far is the development of high-temperature superconducting magnets that are suitably robust and compact so that they can enable a spherical tokamak. This means that future fusion power plants can be compact and efficient—and hence commercially viable."

Of course, fusion reactors are not the only application for superconductors: "There are a number of emerging commercial applications for [high-temperature superconductor] technology within the fusion energy market as well as other sectors, including clean aviation, aerospace, medical, offshore wind and scientific sectors," he said.

Tokamak Energy Ltd. is also working to develop high-temperature superconductors, creating superconducting tapes that are over five times more energy-efficient than their low-temperature predecessors. However, they still need to be cooled down to around -250 degrees Celsius.

And what about the recent fusion breakthrough from Lawrence Livermore?

"The recent breakthrough is an impressive scientific result, but delivering commercial fusion is much more than getting to Q greater than one," Kingham said. "Our fusion power plants will need Q to be 20 or 30 or more."

Even so, this development provides an exciting moment for the entire fusion industry.

"Fusion is a transformative global source of limitless, clean, safe energy and we welcome all progress in the field to attract the best people and investment," Kingham said.

Update 8/10/23, 3:03 a.m. ET: This article was updated to include additional comment from Tokamak Energy Ltd.