– A Flurry of New Records in Tokamaks and Stellarators

The WEST tokamak in Cadarache, France, equipped with ITER‑grade divertors and superconducting coils and effectively positioned as a “sub‑ITER” device, has rapidly gained prominence in recent years. It is designed specifically to test long‑pulse operation and power exhaust under conditions close to those expected in ITER.

In its 2024–2025 experimental campaigns, WEST achieved a series of long‑pulse milestones. In late 2024 it sustained plasma for 824 seconds, and in February 2025 it set a new world record with a 1,337‑second (about 22‑minute) discharge. This corresponded to a total injected and extracted energy on the order of 2.6 GJ, demonstrating that long‑duration, ITER‑relevant operation is moving from a “dream in the control room” into a concrete engineering challenge that can be characterized, optimized, and iterated on.

Meanwhile, the Wendelstein 7-X (W7‑X) stellarator in Greifswald, Germany, has begun to seriously challenge the long‑standing assumption of tokamak dominance in the high‑performance plasma regime. During its OP 2.3 campaign in 2025, W7‑X reported a world‑record long‑pulse triple product, maintaining reactor‑relevant values of the product of plasma temperature, density, and confinement time for about 43 seconds. Under comparable conditions, its performance is now competitive with, and in some cases superior to, leading tokamaks.

In the same campaign, W7‑X also achieved discharges of around 360 seconds with a total energy turnover of roughly 1.8 GJ, showing that combining “high performance × long duration” is increasingly realistic even in stellarator configurations. This is particularly noteworthy because stellarators, by design, offer intrinsically steady‑state magnetic fields and reduced need for complex current drive, which can translate into simpler, more robust reactor operation over the long term.

As a result, the once‑implicit assumption that “large‑scale power plants will inevitably be tokamaks” is clearly fading. We now see multiple competing device concepts:

• Tokamaks in the ITER lineage
• High‑performance stellarators in the W7‑X lineage
• High‑field compact tokamaks driven largely by private startups

Each of these concepts is starting to show distinct strengths when evaluated on core metrics such as triple product, long‑pulse capability and energy turnover, maintainability, and magnetic configuration stability. The key question is no longer “which one survives?” but “how do we allocate capital, talent, and policy support across this portfolio of concepts over time?”.

– Laser Fusion, Materials, and Fuel Innovation

In inertial confinement fusion, the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory has continued to improve shot performance after first achieving ignition in 2022. The focus is shifting from delivering a single historic high‑gain shot to systematically increasing energy output and improving repeatability and stability from shot to shot. The central question is increasingly: “How reliably and how often can we produce high‑gain shots, and at what cost per shot?”, which is exactly the lens required to think about fusion as a future power technology.

Behind these headline results lies a quieter but crucial evolution in materials science and fuel technology. One prominent example is the use of high‑density carbon (HDC) diamond capsules for the fuel. In recent record‑setting shots, significant gains in output have been linked to improved capsule quality:

• Dramatically reducing the number of tiny pits, holes, and internal voids on and within the diamond shell
• Suppressing the introduction of high‑Z impurities that would otherwise mix into the fuel and sap energy from the hot spot

By tightening control over the defect distribution in diamond under extreme pressure and temperature, researchers are improving implosion symmetry and compression efficiency. These improvements translate directly into higher energy gain and make the system less sensitive to small manufacturing imperfections or perturbations during the shot. Recent work has also begun to map how and where diamond capsules are most likely to develop structural weaknesses during implosion, providing a roadmap for next‑generation capsule designs.

On the fuel side, research is advancing on how to secure and process the materials required for future D‑T fusion power plants at industrial scale. Tritium production will rely on breeding blankets that use lithium‑containing materials—often enriched in lithium‑6—to convert fusion neutrons into tritium. This is triggering work on:

• Blanket designs that balance neutron economy with sufficient tritium breeding ratios
• Safe, economical extraction and enrichment processes for lithium‑6
• Assessing material degradation, corrosion, and mechanical performance of blanket and structural materials under intense neutron fluxes

At present, these efforts are still largely at experimental and pilot scale, but they are effectively the early design phase for tomorrow’s fuel supply chains and waste‑management systems. The shape of those chains will influence everything from project economics and regulatory frameworks to geopolitics around lithium resources and tritium handling.

These developments in materials, fuels, and blanket engineering rarely make front‑page news compared with dramatic “world record” plasma shots. Yet over a 10‑ to 20‑year horizon, they are likely to become the critical path for the entire fusion industry. High core performance alone will not make commercial reactors possible; without reliable capsules, robust materials, and scalable fuel cycles, there is no business. That is precisely why today’s quiet, methodical advances in these areas may evolve into some of the most important investment and industrial opportunities in the fusion ecosystem.