Scientists may be close to unlocking the virtually unlimited energy of nuclear fusion due to the development of a cutting-edge device that can superheat plasma.

Japan-based Kyoto Fusioneering has developed a one-megawatt gyrotron. It is a device that generates high-power microwave radiation required for heating and controlling plasma in nuclear fusion reactors. The new tool could be the key to helping Tokamak Energy, a private fusion power company in the United Kingdom, achieve sustainable, commercially viable fusion energy.

Tokamak Energy said in a press release, “The new gyrotron will generate high-power electromagnetic waves for controlling and heating a hydrogen plasma many times hotter than the center of the sun. It will also be used to start up and drive plasma current.”

The company received the gyrotron from Kyoto Fusioneering in late December and plans to install it on its spherical tokamak ST40 this year. Once the fuel-heating technology is operational, Tokamak Energy and several of its partners, including the U.S. Department of Energy, will begin testing lithium on the inner wall of the ST40 for a future fusion pilot plant.

According to Tokamak Energy, the ST40 tokamak is the “most advanced of its kind in the world.” It achieved a record of more than one hundred and eighty million degrees Fahrenheit plasma ion temperature in 2022. This is more than six times hotter than the sun’s core temperature and is considered to be the threshold for commercial fusion energy.

The ultra-powerful gyrotron will advance Tokamak Energy’s efforts to produce nuclear fusion for commercial use by 2030, as the International Energy Forum (IEF) reported.

The IEF explained that nuclear fusion generates nearly four million times more energy than dirty fuels such as coal, oil, and gas and four times more than nuclear fission. Since it doesn’t produce carbon dioxide, other polluting gases, or long-lived radioactive waste, it is an ideal clean, low-cost energy source to that could power the world in the future.

Gyrotrons will probably play a major role in bringing sustainable fusion power to homes and cities. Gyrotrons offer several benefits that can advance progress in fusion research, including their ability to superheat plasma and transmit microwave radiation through waveguides, allowing for more flexibility in positioning.

The new technology also reduces the size needed for the central solenoid which is a key component in tokamaks that generates a strong magnetic field used to initiate and maintain the plasma current during the fusion process.

Tokamak Energy stated that “A gyrotron, which uses Electron Cyclotron Resonance Heating (ECRH), solves one of the key challenges for a spherical tokamak – limited space for a central solenoid, which would otherwise be required to induce the plasma current”.

Tokamak Energy said it plans to use both its current neutral beam injection heating system and gyrotron heating on the ST40 to improve their understanding of the balance needed for future spherical tokamak pilot plants.

Ross Morgan is the director of strategic partnerships at Tokamak Energy. He said, “We’re excited to work with our partners Kyoto Fusioneering to add this important upgrade to our record-breaking fusion machine, and continue to operate ST40 to test and push new boundaries.”

Tokamak Energy

Part 2 of 2 Parts (Please read Part 1 first)

Gyrokinetic Electromagnetic Numerical Experiment (GENE) is an open-source plasma microturbulence program which can be used to efficiently compute gyroradius-scale fluctuations and the resulting transport coefficients in magnetized fusion/astrophysical plasmas. GENE is comprehensive, well benchmarked, portable, and highly scalable.

If you want to determine the temperature of a body of water, you simply place a thermometer in the water. In fusion research, plasma temperature is usually measured using microwaves emitted by the plasma itself. Fluctuations in the electron temperature can also be derived from these emissions.

In addition, by launching microwaves into the plasma, researchers are able to analyze the backscattered radiation to extract information about fluctuations in the electron density. This information provides the number of electrons per unit volume. Utilizing this approach, Höfler and her team were able to characterize fluctuations in both plasma temperature and plasma density.

Two diagnostic methods played a central role in the experiment. The first consisted of using Doppler reflectometers to measure fluctuations in the plasma density. Using three reflectometers from ASDEX Upgrade’s available diagnostic equipment, the team analyzed vortices of various sizes at different locations. The second method utilized a Correlation-Electron-Cyclotron-Emission (CECE) radiometer from the Massachusetts Institute of Technology (MIT) in the U.S. for precise measurements of electron temperature fluctuations.

The comparative plasma simulations in five-dimensional phase space were carried out using the GENE program which was developed at IPP and is globally recognized as a leading tool for numerically modeling turbulent processes inside plasmas. The complexity of these phenomena is so great that the supercomputers used for this study required two months of computing time to model the observed turbulence over just a few milliseconds.

Close collaboration between experimental and theoretical physicists was very important. It is not enough for GENE calculations to reproduce the plasma turbulence correctly. They also have to simulate the complex measurement process, which the researchers have now achieved after years of work. This is the only way that comparability between experiment and numerical calculation can be established at all.

Höfler recalled, “When I received the simulation results, I was genuinely surprised by how well they matched all the experimental data.” Even phenomena that were not expected intuitively were accurately predicted by GENE software

The research team established different temperature profiles for the two plasma discharges studied at ASDEX Upgrade. In Discharge 1, steeper temperature gradients were applied when compared to Discharge 2. As expected, Discharge 1 exhibited greater temperature fluctuations than Discharge 2. However, unexpectedly, the density fluctuations behaved in the opposite way. This is a result that initially seemed inexplicable. Yet, the GENE simulations reproduced this behavior exactly.

Höfler summarizes, “We have proven that GENE reliably predicts the real behavior of the two plasma discharges”. With respect to fusion research, this means that simulations can be used to optimize plasma scenarios to achieve the highest possible energy confinement time. The concept of a digital twin of a fusion reactor is now more tangible, allowing for improved predictions of reactor plasma performance.

GENE Code

Part 1 of 2 Parts

In a comprehensive experimental study, an international team of researchers has confirmed that the calculations of a leading turbulence simulation program match experimental data to an unprecedented degree. This marks an important breakthrough in understanding turbulent transport processes in nuclear fusion reactors.

The simulation study has now been published in the journal Nature Communications. It lays out a crucial foundation for predicting the performance of fusion power plants.

Future fusion power plants will generate usable energy efficiently by fusing light atomic nuclei. Magnetic confinement fusion is the most advanced approach to confining a plasma. A gas is heated to millions of degrees Fahrenheit, within a magnetic field. This plasma is suspended inside a donut-shaped vacuum chamber without touching the wall of the reactor.

The energy released from the nuclear fusion reaction is intended for two purposes. It not only generates electricity but also maintains plasma temperature. To sustain the fusion reaction, the plasma must retain as much energy as possible. This is what researchers refer to as achieving a high-energy confinement time.

To reach this goal, physicists must first understand the extremely complex turbulent processes in plasmas and, ideally, find ways to regulate them. To some extent, turbulence is actually beneficial because it helps transport the helium nuclei, which are byproducts of the fusion reaction, out of the plasma while bringing fresh fuel into the core. However, excessive turbulence decreases the energy confinement time because the energy escapes from the plasma center too quickly.

Dr. Klara Höfler is a physicist who studied this phenomenon at the Max Planck Institute for Plasma Physics (IPP) in Garching near Munich. “You can compare this to a drop of milk in a cup of coffee: if you stir with a spoon, turbulent eddies form, and the liquids mix much faster than without stirring.”

Working with colleagues from IPP and five other research institutions in Europe and the United States, she has made a significant breakthrough in understanding turbulence in fusion plasmas. For the first time, the researchers achieved a comprehensive agreement between experimental results and computer simulations. The team simultaneously compared seven key plasma turbulence parameters which are significantly more than the parameters examined in previous studies.

For the new study, Höfler employed the world’s unique diagnostic equipment at the IPP fusion device Axially Symmetric Divertor Experiment (ASDEX) Upgrade. ASDEX Upgrade is a divertor tokamak at the Max-Planck-Institut für Plasmaphysik, Garching that went into operation in 1991. At present, it is Germany’s second largest fusion experiment after stellarator Wendelstein 7-X. The current purpose of the facility is to make experiments under reactor-like conditions possible, essential plasma properties. They are focused on measuring the plasma density and pressure and the wall load. The ASDEX Upgrade has been adapted to replicate the conditions that will be present in a future fusion power plant.

This equipment allowed her to precisely measure the properties of the multi-million-degree plasma during two discharges with different settings. Her team compared plasma measurement data from two discharges at ASDEX Upgrade with the results of GENE simulations.

ASDEX Upgrade

Please read Part 2 next

Innovative reactor developer Newcleo has acquired a site in Chusclan in the Gard department in southern France on which it will construct an R&D innovation and training center supporting the development of its future fuel assembly manufacturing facility in France.

Newcleo said the Fuel process Assembly Storage Training and Enhanced Reality (FASTER) center will play a key role in its strategy to close the nuclear fuel cycle “while safely producing clean, affordable, and sustainable energy, essential for low-carbon economies”. The center will not store or handle any radioactive materials.

FASTER will host: dedicated spaces for testing engineering solutions and maintenance; advanced training facilities, including rooms equipped for virtual and augmented reality, simulators, and a training workshop with real production equipment; and development and qualification workshops designed to test and optimize manufacturing processes using cutting-edge technologies, such as 3D printing, within a high-tech environment dedicated to innovation and precision engineering. The FASTER center will be developed in collaboration with leading Italian design company Pininfarina.

Newcleo said, “By combining technological innovation with an advanced aesthetic approach, the site will provide an optimized workspace that fosters learning and research in an immersive and functional environment – illustrating how nuclear energy can drive sustainability, support net-zero goals, and secure a safe, abundant, and virtually inexhaustible energy source”.

Stefano Buono is the founder and CEO of Newcleo. He said, “The acquisition of this site marks a key milestone in our strategic roadmap. This innovation and training center, designed with Pininfarina’s renowned elegance and functionality in mind, will play a crucial role in preparing and anticipating the operations of our future pilot fuel manufacturing line … as a first structuring step, it will also support the successful deployment of our pilot line at another site in France.”

Newcleo intends to invest directly in a mixed uranium/plutonium oxide (MOX) plant to fuel its small modular lead-cooled fast reactors. In June 2022, the company announced that it had contracted France’s Orano for feasibility studies on the creation of a MOX production plant.

In December last year, Newcleo submitted its Safety Option File to France’s Authority for Nuclear Safety and Radiation Protection (ASNR) for its fuel assembly testing facility. The ASNR ‘s official opinion on the submitted safety options will contribute to securing the application for authorization to construct such a facility.

According to Paris-headquartered Newcleo’s delivery roadmap, the first non-nuclear pre-cursor prototype version of its reactor is expected to be ready by 2026 in Italy. The first reactor is scheduled to be operational in France by the end of 2031. The final investment decision for the first commercial Newcleo power plant is expected around 2029.

Newcleo said its first-of-a-kind thirty megawatts lead-cooled fast reactor will “serve as an industrial demonstrator, a showcase for Newcleo’s technology, and contribute to the development of the nuclear sector in France”.

Last month, Newcleo announced that it had started the land acquisition process for its demonstration LFR-AS-30 small modular reactor in Indre-et-Loire in the Chinon Vienne et Loire community of municipalities in western France.