Articles tagged with "tokamak"
UK tests first remountable nuclear fusion magnets for 'plug in' power
Engineers involved in the UK’s STEP (Spherical Tokamak for Energy Production) program have successfully tested a novel “plug-and-socket” magnet technology featuring Remountable Joints (RMJs). This innovation allows massive fusion magnets—traditionally built as permanent, solid structures—to be disassembled and reassembled for maintenance, addressing a major engineering challenge in tokamak fusion reactors. By enabling easier internal repairs and component replacements, the RMJs are expected to reduce downtime, lower operational complexity, and cut costs, thereby improving the commercial viability of fusion power plants. Complementing the RMJs, the team developed a unique bladder-based mechanical clamping system that uses a liquid-filled bladder expanding upon freezing to maintain even contact pressure at cryogenic temperatures. This ensures magnet stability and efficiency under the extreme mechanical forces generated during fusion. The clamping system is being prepared for patenting and is designed for scalable manufacturing using various industrial techniques, supporting a robust UK supply chain. STEP aims to demonstrate these technologies in realistic
energynuclear-fusionfusion-magnetstokamakpower-plantsmagnetic-fieldsenergy-innovationUS magnetic control to shield fusion reactor from electron bombardment
A new research initiative at the DIII-D National Fusion Facility aims to address a major challenge in commercial fusion energy: managing high-energy runaway electrons generated during plasma disruptions in tokamak reactors. These electrons can accelerate to near light speed and cause severe damage to the reactor’s inner walls, potentially leading to costly repairs and downtime. Supported by a Department of Energy Office of Science Graduate Student Research fellowship, Auburn University PhD student Jessica Eskew is leading efforts to develop a novel magnetic control strategy that uses the plasma’s own magnetic field structures—specifically magnetic islands—to safely “leak” these energetic electrons out in a controlled manner, rather than allowing them to strike the reactor walls abruptly. The research focuses on manipulating magnetic island dynamics, which are tube-like formations created when magnetic field lines tear and reconnect. Traditionally viewed as detrimental to plasma confinement, these islands are now being explored as potential escape routes for runaway electrons. By controlling how these islands split and reorganize, scientists hope to achieve a gradual, managed release
energyfusion-energyplasma-controlmagnetic-fieldstokamakrunaway-electronsfusion-reactor-materialsChina's EAST Tokamak achieves stable operation at densities beyond limits
Chinese researchers operating the Experimental Advanced Superconducting Tokamak (EAST) have experimentally demonstrated stable plasma operation at densities significantly beyond the conventional empirical limits, effectively accessing a theorized “density-free regime” for fusion plasmas. By implementing a novel high-density operating scheme that combines control of initial fuel gas pressure with electron cyclotron resonance heating during startup, the team optimized plasma–wall interactions, reduced impurity buildup and energy losses, and pushed plasma density to unprecedented levels without triggering disruptive instabilities. This marks the first experimental verification of the PWSO theoretical density-free regime, where plasma stability is maintained despite exceeding traditional density constraints. These findings suggest a practical and scalable method to extend density limits in tokamaks and future burning plasma fusion devices, offering new physical insights into overcoming a long-standing barrier in fusion research. Since fusion power output scales with the square of fuel density, breaking through the density limit is crucial for achieving fusion ignition and advancing nuclear fusion as a clean, sustainable energy source. The EAST
energynuclear-fusiontokamakplasma-physicssuperconducting-materialsfusion-energy-researchsustainable-energy3D magnetic field ‘breakthrough’ for fusion plasma control wins US award
Three researchers from the US Department of Energy’s Princeton Plasma Physics Laboratory (PPPL)—Seong-Moo Yang, SangKyeun Kim, and Ricardo Shousha—have been awarded the 2025 Kaul Foundation Prize for their pioneering work in optimizing three-dimensional (3D) magnetic fields within tokamaks to control edge instabilities in fusion plasma. Their approach uses real-time artificial intelligence (AI) adjustments to proactively prevent plasma instabilities, such as tearing mode disruptions, which can damage the tokamak and halt the fusion process. This marks a significant advancement over traditional methods that react only after instabilities occur. The team’s research highlights the advantages of 3D magnetic fields over conventional two-dimensional fields for maintaining plasma stability. Due to the complexity of calculating and optimizing these fields, they employed machine learning to forecast potential instabilities and make micro-adjustments in real time. This AI-driven method was validated through international collaboration, incorporating experimental data from South Korea’s KSTAR and the DIII
energyfusion-energyplasma-physicstokamakmagnetic-fieldsAI-controlmachine-learningPhotos: Stunning 2025 images reveal world’s biggest nuclear fusion reactor in action
The article highlights the visually captivating and technically impressive imagery of the ITER nuclear fusion reactor construction site in 2025. Photographs from the ITER Communication team and the ITER Photo Group showcase the scale and complexity of the project, capturing everything from massive component handling to intricate details like insulation and reflections. The images emphasize the blend of advanced engineering and aesthetic appeal, with drone shots and ground-level perspectives revealing the reactor’s assembly process and the harmony of its structural geometry. Key milestones in 2025 include the installation of the third vacuum vessel module in the tokamak pit, illustrating ongoing progress in ITER’s assembly. The article also profiles contributors such as Emmanuel Riche, a drone photography pioneer, and Kevin Ballant, founder of the ITER Photo Group, who transitioned from hobbyist to key documentarian. Overall, the collection of photos serves to inspire and inform, offering a unique artistic lens on one of the world’s largest and most ambitious nuclear fusion projects.
energynuclear-fusionITERtokamakenergy-researchfusion-reactorclean-energyJapan's FAST nuclear fusion project releases compact tokamak design
Japan’s FAST (Fusion by Advanced Superconducting Tokamak) nuclear fusion project, led by Starlight Engine and Kyoto Fusioneering, has completed its conceptual design phase just one year after launching in November 2024. The project centers on a compact, low-aspect-ratio tokamak designed to generate and sustain burning plasma using a deuterium-tritium fuel mix, targeting a fusion output of about 50 MW. Unlike experimental reactors focused solely on plasma physics, FAST integrates power generation systems, fuel breeding cycles, and heat extraction into a single operational unit, aiming to demonstrate commercial viability by the 2030s. Key innovations in the FAST design include the use of high-temperature superconducting (HTS) magnets, liquid breeding blanket systems, and efficient tritium fuel cycle technologies. The compact size enabled by HTS coils reduces manufacturing time and costs while enabling high-pressure plasma generation. The project also plans to test advanced components such as innovative divertors and new materials in future
energynuclear-fusiontokamaksuperconducting-magnetsplasma-physicstritium-fuel-cycleenergy-conversionThis startup wants to build a fusion reactor — on a boat
Maritime Fusion, led by CEO Justin Cohen, is pioneering the development of a fusion reactor designed to operate on a ship, aiming to leverage recent advances in fusion technology to bring clean, abundant power to maritime vessels. While fusion reactors have traditionally been developed on land, Cohen believes that placing a tokamak—a leading fusion reactor design—on a boat is feasible and potentially advantageous. Unlike nuclear fission reactors currently powering some submarines and aircraft carriers, fusion promises similar benefits without the risks of meltdowns, radiation, or proliferation. Maritime Fusion’s approach also targets a unique market niche: the high fuel costs at sea, where fusion could compete economically with expensive alternatives like ammonia and hydrogen, unlike on the terrestrial power grid where solar and wind dominate. The startup has raised $4.5 million in seed funding from investors including Trucks VC, Y Combinator, and angel investors, and is actively developing critical components such as high-temperature superconducting cables essential for the tokamak’s powerful magnets. Their first
energyfusion-reactormaritime-technologynuclear-fusionclean-energysuperconducting-cablestokamakWorld-first super magnet breakthrough key to commercial nuclear fusion
UK-based Tokamak Energy has achieved a world-first breakthrough by successfully replicating fusion power plant magnetic fields within its Demo4 system, marking the first full High Temperature Superconducting (HTS) magnet configuration to do so. The Demo4 system generated magnetic field strengths of 11.8 Tesla at -243°C, handling seven million ampere-turns of current through its central column. This milestone validates a critical technical solution for commercial fusion energy, demonstrating system-level performance in a complex magnetic environment akin to that in operational fusion reactors. The system includes 14 toroidal and two poloidal field magnets, enabling engineers to study fusion-relevant forces and gain confidence in scaling HTS technology for future energy-producing fusion plants. Beyond fusion, the breakthrough highlights the broader commercial potential of HTS materials, which offer about 200 times the current density of copper and can be used in power distribution, electric motors for zero-emission flight, and magnetic levitation transport. These magnets are smaller, lighter, and
energyfusion-energysuperconducting-magnetshigh-temperature-superconductorsclean-energytokamakmagnetic-fieldsUK engineers tame fusion plasma in spherical tokamak for first time
A team of scientists at the UK Atomic Energy Authority (UKAEA) has achieved a significant breakthrough in fusion energy research by successfully stabilizing plasma in a spherical tokamak for the first time. Using Resonant Magnetic Perturbation (RMP) coils, they applied a small 3D magnetic field at the plasma edge inside the MAST Upgrade tokamak, located at the Culham Centre for Fusion Energy in Oxfordshire. This method completely suppressed Edge Localised Modes (ELMs), instabilities that occur at the plasma edge and can damage tokamak components or degrade performance. This achievement demonstrates that advanced plasma control techniques used in conventional tokamaks can be adapted to compact spherical tokamaks, which are promising for future fusion power plants. The breakthrough addresses one of the key challenges in fusion energy—maintaining plasma stability at the extremely high temperatures and pressures required for fusion reactions. The findings from MAST Upgrade’s fourth scientific campaign will directly inform the design of ELM control systems for the UK’s
energynuclear-fusiontokamakplasma-stabilitymagnetic-coilsfusion-energy-researchMAST-UpgradeUK's Tokamak Energy reveals high-speed color details of plasma behavior
UK-based fusion company Tokamak Energy has unveiled the first high-speed color footage capturing plasma behavior inside its ST40 spherical tokamak, marking a significant advancement in visualizing fusion processes. Using a camera that records at 16,000 frames per second, researchers observed how deuterium gas fuels the plasma, visible as a bright pink glow, and how lithium granules interact with the plasma. The lithium initially emits a crimson-red light in the cooler outer plasma regions and then glows greenish-yellow as it ionizes in the hotter core, tracing magnetic field lines that confine the plasma. This visual data complements spectroscopy measurements and enhances understanding of plasma fueling and control at temperatures of tens of millions of degrees. These experiments are part of a $52 million upgrade program called LEAPS (Lithium Evaporations to Advance PFCs in ST40), conducted in partnership with the US Department of Energy and the UK’s Department for Energy Security and Net Zero. The program aims to apply lithium coatings to plasma
energyfusion-energyplasma-behaviorlithium-coatingstokamakclean-energyenergy-researchWorld's largest fusion reactor gets critical 4-ton tool from US lab
The Princeton Plasma Physics Laboratory (PPPL) in the United States is providing a critical diagnostic tool—a four-ton X-ray imaging crystal spectrometer (XICS)—for Japan’s JT-60SA, the world’s largest nuclear fusion reactor set to begin operations in 2026. This collaboration, involving PPPL, Japan’s National Institutes for Quantum Science and Technology (QST), and Europe’s Fusion for Energy (F4E), marks one of the first instances of US equipment being installed directly in JT-60SA. The XICS instrument will measure X-rays emitted from the plasma within the reactor, providing highly accurate data on plasma temperature, speed, and particle presence, which are essential for controlling the plasma and maintaining reactor stability. JT-60SA, a superconducting tokamak, will be the most powerful fusion device until the ITER facility in France becomes operational, offering a unique opportunity to explore plasma behaviors at unprecedented power densities. The precise measurements from the XICS will help scientists understand new plasma
energyfusion-reactorplasma-controlX-ray-imaging-crystal-spectrometernuclear-fusiontokamakenergy-researchMIT team creates model to prevent plasma disruptions in tokamaks
Scientists at MIT have developed a novel method to predict and manage plasma behavior during the rampdown process in tokamak nuclear reactors. Rampdown involves safely reducing the plasma current, which circulates at extremely high speeds and temperatures, to prevent instability that can damage the reactor’s interior. However, the rampdown itself can sometimes destabilize the plasma, causing costly damage. To address this, the MIT team combined physics-based plasma dynamic models with machine learning techniques, training their model on experimental data from the Swiss TCV tokamak. This hybrid approach allowed the model to accurately and quickly predict plasma evolution and potential instabilities during rampdown using relatively small datasets. The new model not only enhances prediction accuracy but also translates these predictions into actionable control instructions, or “trajectories,” that a tokamak’s control system can implement to maintain plasma stability. This capability was successfully tested on multiple TCV experimental runs, demonstrating safer plasma rampdowns and potentially improving the reliability and safety of future nuclear fusion reactors. The research,
energynuclear-fusionplasma-physicsmachine-learningtokamakclean-energyplasma-stabilityCommonwealth Fusion Systems books a $1B+ power deal for its future fusion reactor
Commonwealth Fusion Systems (CFS) has secured a power purchase agreement worth over $1 billion with Italian energy company Eni for electricity generated by its first commercial fusion reactor, Arc, expected to come online in the early 2030s. The 400-megawatt Arc reactor will be located near major U.S. data centers, and this deal follows a similar agreement with Google announced earlier. While specific details about the power volume and timeline remain undisclosed, CFS CEO Bob Mumgaard confirmed that the demonstration-scale Sparc reactor, designed to validate the technology, is 65% complete and on track for activation in late 2026. CFS’s fusion technology is based on a tokamak design using superconducting magnets to confine plasma and generate energy through fusion reactions. Sparc aims to demonstrate net-positive power output, a critical milestone before scaling to the larger Arc plant. The company has raised nearly $3 billion from investors including Nvidia, Google, Breakthrough Energy Ventures, and
energyfusion-reactorCommonwealth-Fusion-SystemsArc-reactorSparc-reactortokamakclean-energyITER fusion reactor to get spectrometer to track high-energy neutrons
The ITER fusion reactor, the world’s largest tokamak, is set to install a High Resolution Neutron Spectrometer (HRNS) to measure the number and energies of high-energy neutrons emitted by the plasma during fusion reactions. Developed collaboratively by physicists and engineers from the Polish Academy of Sciences, University of Uppsala, and the Istituto per la Scienza e Tecnologia dei Plasmi in Milan, the HRNS is a critical diagnostic tool designed to track the ratio of tritium to deuterium (nt/nd) in the plasma core. This measurement is essential for understanding fuel composition, ion temperature, and combustion quality, thereby enabling optimized and safe reactor operation. The spectrometer will be installed behind a thick concrete wall surrounding the fusion chamber to withstand the harsh environment. The HRNS is uniquely designed as four independent sub-assemblies, each tailored to different neutron flux intensities and operating principles. These include the Thin-foil Proton Recoil (TPR) sub
energyfusion-reactorneutron-spectrometerplasma-diagnosticsITERnuclear-fusiontokamakITER fusion project repairs most affected 485-ton vacuum vessel sector
Sector #8, a critical 440-ton vacuum vessel component of the ITER fusion reactor, has successfully completed a complex 20-month repair process after initial dimensional non-conformities halted its sub-assembly in December 2023. This sector was the most affected among the first three vacuum vessel sectors, which exhibited significant deviations from planned assembly sequences due to dimensional issues. The repair involved innovative procedures and tooling, including pivoting the heavy component from vertical to horizontal positions and transferring it to the Cryostat Workshop for detailed restoration work on its bevel joint geometry. The repair process was complicated by the need to simultaneously address three vacuum vessel sectors, while the Assembly Hall could only support two operations at once. Sector #8’s repair was conducted separately in the Cryostat Workshop, where workers accessed one side at a time, requiring the component to be rotated multiple times using specialized cranes and upending tools. After completing repairs on both sides, the sector was returned to sub-assembly tooling and is now being prepared for installation
energyfusion-reactorvacuum-vesseltokamakITERthermal-shieldtoroidal-field-coilsSuper-X exhaust with long 'legs' could reduce nuclear reactor heat
An international research team at the UK’s MAST Upgrade facility has successfully demonstrated the Super-X divertor, an innovative exhaust system for fusion reactors that can reduce heat loads on reactor walls by more than tenfold compared to previous designs. The Super-X divertor features longer “legs” that provide the superheated plasma—reaching temperatures over 10,000°C—more space and time to cool before contacting any solid surface. This design significantly lowers the thermal and particle stress on the reactor’s divertor, a critical component responsible for handling the extreme conditions at the plasma edge, thereby addressing a major engineering challenge for commercial fusion power plants. The breakthrough proves that plasma conditions in the divertor can be independently controlled without affecting the core plasma where fusion energy is produced, a key factor for stable and continuous reactor operation. Additionally, the Super-X design is easier to manage than conventional short-legged divertors and offers flexibility for future reactor designs by balancing performance with engineering complexity. These findings mark a world-first in divert
energyfusion-reactorplasma-coolingSuper-X-exhaustnuclear-fusiontokamakreactor-heat-managementFusion breakthrough uses inverted D plasma to solve key energy challenge
Researchers at the DIII-D National Fusion Facility in the US have demonstrated a significant breakthrough in nuclear fusion reactor control by using a plasma configuration called “negative triangularity,” where the plasma cross-section is shaped like an inverted “D” with the curved side facing the tokamak’s inner wall. Contrary to previous expectations that this shape would be less stable, experiments in 2023 showed that negative triangularity plasmas can achieve high pressure, density, and current simultaneously while maintaining excellent heat confinement. This configuration also exhibited unexpectedly low levels of plasma instability, which is critical for sustained fusion reactions and reducing damage to reactor walls. A key challenge in tokamak design is managing the heat at the plasma edge to protect the reactor’s interior while keeping the core hot enough for fusion. The negative triangularity approach successfully combined high plasma confinement with “divertor detachment,” a condition that cools the plasma boundary and reduces heat load on material surfaces without triggering instabilities. This integrated solution addresses the core-edge heat management
energynuclear-fusionplasma-physicstokamakfusion-reactorenergy-breakthroughfusion-energy-researchWorld’s largest tokamak gets advanced tool to measure fusion heat
The JT-60SA fusion facility in Naka, Japan, has reached a major milestone with the installation of the Edge Thomson Scattering (TS) diagnostics system, complementing the already developed core TS system. Thomson Scattering is a vital diagnostic technique that uses laser light scattered by plasma electrons to measure electron temperature and density, key parameters for understanding and controlling fusion reactions. The combined core and edge TS systems provide comprehensive, high-resolution coverage of the plasma cross-section, with the core system measuring 46 points from 2.6 m to 3.73 m radius and the edge system covering 49 points from 3.7 m to 4.17 m radius. The fine spatial resolution, narrowing to 5.5 mm at the plasma edge, enables detailed analysis of critical plasma features such as the pedestal profiles. Designed for high operational performance, the core TS system operates at 50 Hz and the edge system at 100 Hz, allowing rapid data acquisition essential for plasma stability and control
energyfusion-energytokamakplasma-diagnosticsThomson-scatteringmagnetic-confinement-fusionJT-60SANew AI method accelerates plasma heat defense in reactors
Researchers from Commonwealth Fusion Systems, the DOE’s Princeton Plasma Physics Laboratory, and Oak Ridge National Laboratory have developed a new AI method called HEAT-ML to accelerate the protection of fusion reactors from extreme plasma heat. HEAT-ML enhances the existing Heat flux Engineering Analysis Toolkit (HEAT) by using a deep neural network trained on about 1,000 SPARC tokamak simulations to rapidly generate 3D “shadow masks.” These masks identify regions of the reactor’s inner walls shielded from direct plasma contact, which is critical to preventing damage from plasma temperatures exceeding those at the Sun’s core. Traditional HEAT simulations can take up to 30 minutes per run, whereas HEAT-ML produces results in milliseconds, dramatically speeding up the design and operational decision-making processes for fusion systems. The AI was initially tested on 15 tiles near the bottom of SPARC’s exhaust system, the area expected to experience the highest heat loads. By quickly and accurately locating magnetic shadows, HEAT-ML supports
energyfusion-energyAI-in-energyplasma-heat-managementfusion-reactorstokamakenergy-technologyUS study finds lithium in reactor vessel could boost nuclear fusion
A recent US-led study involving nine institutions has found that using lithium as a wall material in tokamak fusion reactors could significantly enhance fusion performance. Lithium coatings on reactor walls help stabilize plasma by creating an even temperature gradient from the plasma core to its edge, which is crucial for maintaining stable plasma conditions needed for commercial fusion. Unlike pre-applied lithium coatings, injecting lithium powder during fusion operation proves more effective, as it forms a self-repairing molten layer that protects the vessel walls from the extreme heat—temperatures hotter than the sun’s core—by creating a gas or vapor shield. This protective mechanism reduces wall erosion and limits unwanted material entering the plasma, thereby improving plasma-facing surface durability. The study also addressed concerns about fuel trapping in lithium, finding that the thickness of lithium coatings before plasma shots does not significantly affect fuel retention. Lithium’s ability to absorb fuel atoms rather than reflect them helps stabilize the plasma edge, enhance plasma confinement, and enable higher power densities—key factors for developing compact and efficient
lithiumnuclear-fusionfusion-reactormaterials-scienceplasma-facing-componentstokamakenergy-innovationITER plans half-mile boron gas pipelines to purify fusion plasma
The ITER fusion project is developing an extensive boronization system to purify plasma and reduce impurities in its tokamak reactor, following a 2023 decision to switch plasma chamber armor from beryllium to tungsten. This system applies a thin boron layer (10-100 nanometers) to all plasma-facing surfaces, which captures oxygen impurities that could otherwise increase radiative losses and destabilize the plasma, especially during discharge initiation. The boron layer is deposited using diborane gas (a hydrogen-boron compound) injected into the tokamak, where it decomposes and chemically bonds to surfaces via a glow-discharge-assisted plasma process. The gas injection system involves over a kilometer of piping and 21 injection points within the facility. Designing this system at ITER’s unprecedented scale and in a tritiated environment posed challenges, including ensuring the compatibility of high-energy anodes with frequent boronization cycles and achieving even boron coverage. These issues were addressed through international collaboration and testing with other
energynuclear-fusiontokamakboronizationplasma-purificationITERfusion-technologyWestinghouse to assemble core of the world’s largest fusion reactor
Westinghouse Electric Company has secured a $180 million contract with the ITER Organization to undertake the final assembly of the tokamak’s core component—the vacuum vessel—at the world’s largest nuclear fusion facility, ITER. This vacuum vessel is a double-walled steel chamber that will contain the fusion plasma, and Westinghouse will weld together its nine sectors to form the torus-shaped chamber. The contract marks a significant milestone as ITER progresses toward its goal of achieving 500 MW of fusion power output from 50 MW of input heating power, demonstrating a tenfold energy gain. ITER aims to conduct initial deuterium-deuterium fusion operations by 2035 and ultimately prove fusion as a large-scale, carbon-free energy source, although it will not generate electricity itself. Westinghouse, a veteran in nuclear fission technology, has been involved with ITER for over a decade, contributing to the manufacturing of vacuum vessel sectors alongside partners in the AMW consortium. The ITER project is a massive international collaboration
energynuclear-fusionWestinghouseITERtokamakvacuum-vesselfusion-reactorUS researchers solve tokamak plasma mystery with elusive ‘voids’ discovery
Researchers at the University of California, San Diego, have developed a new theoretical model that may explain a longstanding discrepancy in nuclear fusion research related to plasma behavior at the edge of tokamak reactors. The study, led by physicists Mingyun Cao and Patrick Diamond, focuses on the plasma boundary—a critical region for sustaining fusion reactions and protecting reactor components from extreme heat. Previous simulations underestimated the width of the turbulent layer at the plasma edge, a problem known as the “shortfall problem,” which has hindered accurate predictive modeling of plasma dynamics. The breakthrough centers on previously overlooked structures called “voids,” which are inward-moving, density-depleted formations at the plasma edge. While past research emphasized outward-moving, density-enhanced “blobs,” the role of voids remained unclear. Cao and Diamond’s model treats voids as coherent, particle-like entities that, as they move from the cooler plasma edge toward the hotter core, generate plasma drift waves by interacting with steep temperature and density gradients. These waves transfer
energynuclear-fusiontokamakplasma-physicsfusion-reactorturbulence-modelingplasma-boundaryTokamaks could be prevented from overheating with X-point radiator
energyfusiontokamakplasmareactorefficiencyheat-managementUK fusion device gets heating components to withstand extreme temperature
fusionenergyplasma-heatingtokamakmaterialselectromagnetic-wavesnuclear-fusion'Trái tim' của lò phản ứng nhiệt hạch lớn nhất thế giới
energyfusionITERsuperconducting-magnetsclean-energytokamakplasma