The quest for a nuclear power-fuelled future has always been beset with insurmountable engineering and scientific challenges. But recent developments in the quest for alternate energy through nuclear fusion have made such a future more scaleable, reports the World Economic Forum.
At an estimated cost of $25 billion, the International Thermonuclear Experimental Reactor (ITER) project is building a prototype fusion reactor, called a tokamak, in southern France that aims to conduct the first test of super-heated plasma by 2025 and generate first full-power fusion by 2035.
Researchers across the world are inching closer to generating power from nuclear fusion, growing confident about making the clean and endless energy source viable, with each demonstration, be it with mayonnaise, a Z-pinch or tokamak reactors.
Here are some of the latest advances that have reignited hope, and allowed scientists to take small steps toward harnessing the power of the universe. But first, let’s brush up the basics.
What is fusion power?
Fusion power relies on clouds of charged particles you can squeeze the literal daylights out of – it’s the reaction that powers the sun.
Potentially offering an inexhaustible supply of zero-carbon energy, nuclear fusion is incredibly hard to generate and maintain, as a fusion reaction requires more power than it generates.
Mike Mauel of Columbia University recently assessed the state of nuclear fusion research, noting that one of the obstacles in developing fusion power is that it requires an immense amount of heat. No one has yet created a fusion reactor that generates more energy than it uses.
But with major breakthroughs on that front in the last few years, the case for fusion technology as the pathway to satisfying future power needs has gained momentum, especially in light of the climate emergency propelled by fossil fuels.
The US Department of Energy published a crucial study last month also indicating that we are on the brink of creating viable power through nuclear fusion.
What is nuclear fusion?
While most nuclear power stations in the world run on fission power that can be harnessed to produce nuclear weapons, fusion reactions can generate even more power but without the long-lasting radioactive waste. In theory, fusion is also easier to control; its main ingredient isn’t uranium but water containing stable hydrogen isotopes.
Moreover, unlike nuclear fission that involves the splitting of the atomic nucleus, fusion power is produced when two light atoms fuse into one under extreme pressure and temperature.
The total mass of the new atom is less than that of the two that formed it; the “missing” mass is given off as energy, as described by Albert Einstein’s equation E=mc2.
The process, which requires temperatures of approximately 39 million degrees Celsius, can produce up to 17.6 million electron volts of energy. The only bi-product of the process is helium, meaning that no greenhouse gases are released into the atmosphere.
In the sun, massive gravitational forces create the right conditions for fusion in its core, but on earth, they are much harder to achieve. But containing a buzzing mix of superhot ions in the lab has proven extremely challenging.
Stellerators like Germany’s Wendelstein 7-X, on the other hand, rely more heavily on banks of externally applied magnetic fields. While this makes for better control over the plasma, it also makes it harder to reach the temperatures needed for fusion to occur.
To recreate the conditions necessary for fusion reactions, physicists sometimes use inertial confinement studies; it often involves the placing of metal pellets containing frozen gas in a centrifugal chamber and bombarded with high-powered lasers. This compresses the gas and heats it up to a few million Kelvin.
Arindam Banerjee, an associate professor of mechanical engineering and mechanics at Lehigh University, demonstrated the Rayleigh-Taylor instability (between the metal of the pellet and the gas that causes explosion) last month, using mayonnaise at low temperature.
Unlike Banerjee, scientists have traditionally used intense magnetic fields for generating nuclear power in the laboratory. This early form of plasma confinement called the Z-pinch uses the specific orientation of a plasma’s internal magnetic field to apply what’s known as the Lorentz force to the flow of particles, effectively forcing its particles together through a bottleneck.
It was all but abandoned for its shortcomings until the Experimental Advanced Superconducting Tokamak (EAST) set a milestone for the fusion journey.
ITER and other tokamak studies
The tokamak fusion reactor at China’s Institute of Plasma Physics became operative in November and is known to swirl insanely hot plasma in such a way that it generates its own internal magnetic fields, helping contain the flow. This approach gets the plasma cooking enough for it to release a critical amount of energy.
It is the first reactor in the world to reach 100 million degrees Celsius, nearly seven times hotter than the sun’s core and the temperature at which hydrogen atoms can begin to fuse into helium.
These results are expected to provide valuable insights for the ITER project, the world’s biggest and most expensive fusion research initiative that is being financed and supported by India, Japan, China, Russia, South Korea, the EU and the US. Its facility in Provence, France, is being hailed as “the key experimental step between today’s fusion research machines and tomorrow’s fusion power plants.”
Researchers at the US Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) have made a significant breakthrough in understanding the process. Specifically, they have uncovered a mechanism which aids in controlling volatile disruptions which plague the management of the reaction.
As part of their methodology in controlling those events, the researchers are relying upon a predictive deep learning artificial intelligence (AI) model, a discovery that will certainly prove beneficial for ITER.
A collaboration between MIT and the start-up Commonwealth Fusion Systems is designing a fusion reactor capable of producing more power than it consumes. Their research will also complement the work done by ITER.
Besides ITER and China, another privately funded UK venture called Tokamak Energy announced its plasma had hit 15 million degrees Celsius for the first time in 2018. The Canadian government announced last year it is investing $37.5 million in General Fusion, a private company founded in 2002 that focuses on an approach known as magnetised target fusion.
An answer to energy crisis in the time of climate action?
Notwithstanding our contentious history with nuclear power and radiation risks, headlining with disasters like Chernobyl in 1986 and more recently, Fukushima in Japan in 2011, research teams continue to search for the elusive sustainable solution.
That is because when it comes to nuclear fusion power technology, the prize is immense – boundless, safe, clean and cheap energy.
Today, the most promising combination for power on earth, according to scientists, is the fusion of a deuterium atom with a tritium one. Deuterium is a stable hydrogen isotope occurring abundantly in the earth’s oceans. So a gallon of seawater (3.8 litres) could produce as much energy as 300 gallons (1,136 litres) of petrol.
That said, nuclear fusion reactors could be easily used as a facade for clandestine production of plutonium 239, implication for which are dire for a world trying to curb nuclear proliferation. Policymakers should perhaps get to work in drawing up regulatory codes for countries likely to be involved in nuclear fusion energy generation and supply.
Even though ITER sees nuclear fusion power plants becoming mainstream only after 2050, advances in magnet technology have enabled researchers at MIT to propose a new design for a practical compact fusion reactor that might deliver a net power output perhaps within the next decade or so.
Another project in France is projected to start producing net power in 2035 – though only for minutes at a time.
Researchers from the University of Washington have also found an alternative approach to stabilising the plasma in a Z-pinch which not only works, but also fits on a tabletop. The 1.5m device was able to sustain a nuclear fusion reaction for five microseconds, reported science journal Futurism in April.
While clean abundant fusion energy remains a distant dream, this renewed approach to a less complex form of plasma technology could help meet immediate demands if perfected, and may also prove to be a cheaper, more compact source of clean power in its own right.
Although there is a long way to go before fusion becomes major electricity source, ongoing investment in fusion research is worth it. With the recent breakthroughs, it is safe to assume that a nuclear-fuelled future will not be a speck on the horizon for long.
Prarthana Mitra is a Staff Writer at Qrius.