Fusion energy is as old as our cosmic system. It fuels the sun and the stars. However, its application on our planet is still experimental.
According to a mid-July report, investments in the field rose more than $900 million this year to about $7.1 billion. However, experts believe that the growth in investments is not yet adequate. It is lower than the rise of US$1.4 billion achieved last year and US$2.8 billion in 2022.
According to Andrew Holland, the head of the Fusion Industry Association:
“The growth seen in the last 12 months is positive, but will not be enough to deliver fusion’s ambitious goals.”
As in any other sector, growth can only be achieved through innovation. Today, we will explore one such efficient and crucial innovation—aimed at eliminating the need for an Ohmic heating solenoid—that could be the most impactful design driver in realizing economical, compact fusion tokamak reactor systems.
But before delving deeper into the research and its ramifications, we must have a brief overview of how fusion energy science works and the role tokamak systems play in it.
The Science of Fusion Energy and Tokamak Systems
It is a multidisciplinary field of science that aims to develop an energy source based on controlled fusion. The basic principle of fusion involves combining two nuclei to form a nucleus.
At a more practical level, fusion on Earth involves creating conditions that result in the generation of sustained plasmas, which are gases so hot that electrons go free from atomic nuclei. Researchers use electric and magnetic fields to control the resulting collection of ions and electrons because they have electrical charges. The mechanism is what inspires the name control fusion.
Tokamak systems help confine plasma using magnetic fields in a doughnut shape called a torus. Over the years, Tokamaks have emerged as the leading plasma confinement concept for the fusion power plants of the future. The research we shall discuss in the coming segment deals with optimizing the tokamak space.
Compact, Spherical Fusion Vessels: A Smaller Tokamak as a More Economical Fusion Option
An extended team of researchers have been at the helm of this research, including scientists from the U.S. Department of Energy (DOE), Princeton Plasma Physics Laboratory (PPPL), the private company Tokamak Energy, and Kyushu University in Japan. Their proposal is simple in terms of the idea: a compact, spherical fusion pilot plant that heats plasma using only microwaves.
The use of microwaves would eliminate the need for a massive coil of copper wire called a solenoid located near the center of the vessel to heat the plasma.
While elaborating on the usefulness of removing this conventional ohmic heating approach, Mayasuki Ono, the principal research physicist at PPPL and the lead author of the paper, said:
“A compact, spherical tokamak plasma looks like a cored apple with a relatively small core, so one does not have the space for an ohmic heating coil. If we don’t have to include an ohmic heating coil, we can probably design a machine that is easier and cheaper to build.”
In achieving its objective, the experiment leverages a technology called ECCD, standing for Electron Cyclotron Current Drive, which can simultaneously drive a current in and heat the plasma. The researchers have further worked out a computer code called TORAY, which, in combination with another one called TRANSP, can scan the aiming angles of the beam to ascertain the highest efficiency and minimize the requirement of power to drive the necessary current.
The researchers have further identified the mode of ECCD that would work best for each phase of the heating process. The probable choices involve two modes:
- O mode or ordinary mode
- X mode or extraordinary mode
Both these modes are useful and contribute to the overall functioning of the system. The X mode works best when one needs to ramp up the plasma’s temperature and current. The O mode is the fittest option for maintaining the plasma’s temperature and current after the ramp-up.
In summarizing the alternative heating options, Ono said:
“O mode is good for a high-temperature, high-density plasma. But we found that O mode efficiency becomes very poor at lower temperatures, so you need something else to take care of the low-temperature regime.”
The researchers also highlighted the importance of keeping the plasma free of impurities. Strong magnetic fields largely confine the plasma inside a tokamak in a particular shape, but sometimes plasma can come close to the interior walls of the tokamak, allowing atoms from the walls to sputter off and enter the plasma.
While the research proposals are still experimental, we can already see the involvement of commercial entities that can take this solution forward, scale it up, and make the application of fusion energy more optimized and energy efficient. In the coming segment, we discuss Tokamak, the company that has already been involved in the process.
#1. Tokamak Energy Inc.
Tokamak has been at the forefront of developing the technology required to successfully deliver fusion energy in the 2030s. Its vision is to make fusion energy clean, secure, affordable, and readily available.
So far, the company has earned 77 families of patent applications and raised US$250 million in total. Of this US$250 million, US$200 million came from private investors, and the rest from the UK and US governments.
In its operational life, the company has added many feathers to its cap. For instance, in 2022, the company became the first private fusion company to achieve 100 million degrees Celsius plasma ion temperature in a tokamak, the threshold for fusion at a commercial scale.
The same year, the company was also accredited with the highest plasma ‘triple product’ of any private fusion company, a key measure of plasma temperature and confinement time.
We have already discussed the spherical Tokamak, which is one of the best-researched and widely regarded paths to fusion energy. Its advantages include operational efficiency, plasma stability, and cost-effectiveness.
Tokamak’s ST40 high-field compact spherical tokamak is one of the most advanced in this field. Through this, Tokamak achieved a plasma ion temperature of 100 million degrees Celsius, which was six times hotter than the center of the Sun.
Tokamak is also constructing a Demo4 magnet system in a purpose-built test facility. The system consists of 44 individual HTS coils assembled into 14 toroidal field limbs and two poloidal field coils in a cage-shaped structure. It can operate in a vacuum at 20 Kelvin (-250°C) with a magnetic field strength nearly a million times stronger than the Earth’s magnetic field.
#2. Helion
Another company doing game-changing work in this field is Helion. The company claims to have built the world’s first fusion power plant. Helion’s fusion generator is also capable of raising fusion fuel to greater than 100 million degrees Celsius. Moreover, it can extract electricity with a high-efficiency pulsed approach.
Technology-wise, Helion’s solution leverages magneto-inertial fusion technology. Helion’s technology has three standout features that make it different from other approaches available in this space. To allow the adjustment of power output based on need, the company leverages a pulsed, non-ignition fusion system.
Similar to how a regenerative braking system works in an electric car, the Helion system can directly recover electricity. This makes the Helion system much more energy efficient, as the other available fusion systems heat water to create steam that turns the turbine, losing a lot of energy in the process.
Helion utilizes deuterium and helium-3 (D-³He) as fuel. The fusion of these two produces charged particles that can be directly recaptured as electricity, keeping the system small, efficient, fast, and cost-effective. The use of deuterium and helium-3 (D-³He) as fuel helps reduce neutron emissions and significantly brings down the engineering challenges that arise in the use of deuterium-tritium fusion fuel.
Importantly, the company believes that its fusion power could become one of the lowest-cost sources of electricity, ideally producing electricity at a rate of US$0.01 per kWh.
According to the latest available information, the company, established in 2008, could raise US$500 million by the end of 2021, reaching a valuation of $1.25 billion. This latest round was spearheaded by Sam Altman, CEO of OpenAI, who personally invested $375 million, highlighting the strong belief in Helion’s potential to revolutionize energy production through fusion technology. The total funding now stands at $577 million, which will be directed towards completing Helion’s seventh prototype, Polaris, and moving closer to commercializing fusion energy by 2024.
Advanced technological work from companies like Tokamak and Helion is helping the space of fusion energy make great strides. The specific research we cited to initiate our discussion was an outcome of a private-public partnership. It shows that there is a steady and systemic transfer of knowledge and capabilities between research institutions and commercial companies.
The Future of Fusion Vessels: Innovative Thinking Towards Optimization of Resources
Becoming successful with fusion would require delving deeper into its science. The scientists are more curious than ever.
Mayonnaise Aids Researchers in Solving Complex Fusion Energy Challenges
A team of Lehigh University researchers is using mayonnaise as a key ingredient in their ongoing research on the phases of Rayleigh-Taylor instability. This research could inform the design of future inertial confinement fusion processes for clean energy.
According to Arindam Banerjee, the Paul B. Reinhold Professor of Mechanical Engineering and Mechanics at Lehigh University and Chair of the MEM department in the P.C. Rossin College of Engineering and Applied Science:
“The team is still working on the same problem, which is the structural integrity of fusion capsules used in inertial confinement fusion, and Hellmann’s Real Mayonnaise is still helping us in the search for solutions.”
Mayonnaise helps the team by acting as a solid, which starts to flow when subjected to a pressure gradient. The Rayleigh-Taylor problem, a well-known issue in physics, involves the phenomenon that occurs between materials of different densities when the density and pressure gradients are in opposite directions, creating an unstable stratification. The use of Mayonnaise helps try out possible solutions while negating the need for high temperatures and pressure conditions, which are exceedingly difficult to control.
Cold Fusion Without Extreme Temperatures
Another recent breakthrough in cold fusion has rekindled hopes for achieving clean energy without the need for extremely high temperatures and plasma, traditionally associated with nuclear fusion.
This development, which was long considered fringe science, involves using materials science, rare metals, and specific chemical processes to achieve nuclear fusion at lower temperatures.
The scientific community had previously dismissed cold fusion due to the inability to replicate early experimental results, but a new peer-reviewed study published in Nature suggests a possible pathway forward by observing neutron emissions during experiments with deuterated titanium powder under acoustic cavitation. This discovery may pave the way for more research into cold fusion as a viable alternative energy source, offering the potential for clean, virtually limitless power.
The study’s findings challenge the longstanding belief that nuclear fusion requires the extreme conditions found in stars, such as millions of degrees of temperature and powerful magnetic fields. Instead, this new approach explores the potential of achieving fusion through different mechanisms, which could revolutionize the energy landscape by providing a more accessible and less resource-intensive method for generating energy.
If successful, cold fusion could bypass the massive infrastructure and energy input required by traditional fusion methods, making it a game-changer in the quest for sustainable and clean energy solutions.
AI: A Game-Changer in Stabilizing Nuclear Fusion Reactions
With increasing sophistication and growing abilities, AI is revolutionizing the field of nuclear fusion by predicting and preventing plasma instabilities, which have historically impeded the sustainability of fusion reactions.
Researchers at Princeton University and the U.S. Department of Energy’s Princeton Plasma Physics Laboratory have developed an AI model capable of foreseeing plasma disruptions, such as tearing mode instabilities, up to 300 milliseconds before they manifest. This allows the AI to make real-time adjustments to the reactor’s parameters, maintaining the plasma’s stability and preventing the reaction from terminating prematurely.
The AI’s predictive power comes from its training on data from past experiments, enabling it to respond dynamically to potential instabilities in ways that traditional physics-based models cannot.
As plasma is inherently unstable and complex, maintaining its stability has been a significant challenge in sustaining nuclear fusion. Traditionally, methods have focused on mitigating instabilities only after they have begun to disrupt the plasma, often too late to save the reaction.
By leveraging AI’s ability to predict and preemptively counter these instabilities, the fusion process becomes more stable and viable, edging closer to the realization of practical and sustainable fusion energy. This advancement not only enhances the prospects of fusion as a limitless energy source but also underscores the critical role AI is playing in overcoming the most challenging hurdles in fusion research.
What Does the Future Hold?
The future would see companies devising fusion power solutions that optimize space and the use of resources in terms of energy and cost. According to Omar Hurricane, a program leader at Lawrence Livermore National Laboratory, where the National Ignition facility is located:
“Fusion looks a lot more plausible now than it did ten years ago as a future energy source.”
In 2023, scientists made a breakthrough when they created a nuclear reaction that could generate more energy than it consumed. Reportedly, the experiment deployed a set of 192 lasers to deliver 2.05 megajoules of energy onto a pea-sized gold cylinder containing a frozen pellet of the hydrogen isotopes deuterium and tritium.
The energy was so intense that it collapsed the capsule. The temperature achieved could only be matched by stars and thermonuclear weapons. In more specific terms, as suggested by the laboratory, 3.15 megajoules of energy were released—nearly 54% more than the energy that went into the reaction and more than double the previous record of 1.3 megajoules.
Many researchers believed that the experiment results held great potential for the future. According to Michael Campbell, former director of the fusion laboratory at the University of Rochester in New York and an early proponent of NIF while at Lawrence Livermore lab, the breakthrough could boost confidence in the promise of laser fusion power and ultimately open the door to a new program focused on energy applications. Kim Bundil, Lawrence Livermore laboratory director, believed it to be the “fundamental building block of an inertial confinement fusion power scheme.”
The trial and its success also demonstrated the need for many future developments that would make the process more robust. For instance, for the trial to become a viable process, the energy released compared to the energy that goes into producing the laser pulses needs to grow by at least two orders of magnitude.
The future also needs to see a dramatic increase in the rate at which the lasers can produce the pulses and how quickly they can clear the target chamber to prepare it for another burn.
While these efforts will continue in the days to come, we shall conclude today’s discussion with the mention of another vital project in this space – the US$22-billion ITER project, a collaboration between China, the European Union, India, Japan, Korea, Russia, and the United States. The project works towards achieving self-sustaining fusion, where the energy from fusion would produce more fusion.
Slowly and steadily, as the current experiments culminate in their finality, fusion energy will become more cost-effective, optimized, and ready for greater mass adoption.