A scale model of Kyoto Fusioneering's FAST project fusion reactor. Blankets are removed and replaced through gaps at the top of the reactor structure. November 27, Ota Ward, Tokyo (©Sankei by Maki Matsuda)
A race with no time to spare has begun over the creation of a "sun on Earth." Nuclear fusion, which generates energy using the same principles that power the sun, is shifting rapidly from an era of international cooperation focused on large-scale research to one of private sector-driven industrial competition aimed at near-term commercialization.
While large-scale market expansion is not expected until the late 2030s, many believe the global balance of power in fusion will be determined during the 2020s. Governments are therefore accelerating national strategies and cultivating domestic industries. Japanese players are also moving decisively, unveiling plans to build facilities that will demonstrate electricity generation and signaling that candidate construction sites could be selected as early as 2027.
A Deep National Foundation in Fusion Research
Japan has long been at the forefront of nuclear fusion research and development. Therefore, it has built a deep reservoir of expertise. This includes projects such as the world-leading fusion plasma experimental facility JT-60SA in Naka, Ibaraki Prefecture, as well as participation in the International Thermonuclear Experimental Reactor (ITER), now under construction in southern France.
In June 2026, the Japanese government revised its Fusion Energy Innovation Strategy, which sets the direction for national fusion research. Drawing on the knowledge and human capital accumulated over decades, the updated strategy aims to demonstrate fusion-based power generation in the 2030s.
A Privately Led Push Toward Power Generation
Riding this momentum, Kyoto Fusioneering, a fusion startup spun out of Kyoto University and headquartered in Tokyo, launched the privately led FAST project in November 2025. The project targets both power generation demonstration and eventual practical application in the 2030s. In December 2025, the company announced that it had completed a conceptual design as part of an effort to assess the feasibility of manufacturing a power generation system.
The project will now advance to detailed design, fundraising, and site selection, with construction targeted to begin sometime after 2028. Potential locations are already being surveyed nationwide, and the company plans to narrow these down to a candidate site within the next year. Total funding of between ¥500 billion JPY ($3.2 billion USD) and ¥700 billion ($4.5 billion) will be raised through a mix of public and private sources.
Race Against Time
Satoshi Konishi, the company's chairman and founder, has spent more than four decades researching fusion at Kyoto University and other institutions. He said the industry had "finally entered an era in which the private sector takes the lead in building fusion plants," calling it a turning point as development moves decisively toward construction.
Konishi expressed confidence that Japan remains among the front-runners in the global race toward commercializing fusion.
Kyoto Fusioneering describes its work as the first instance in Japan of a private company completing such a conceptual design. However, excluding ITER, it may be considered a world first. Konishi also notes that while many proposals have been labeled "conceptual designs" in the past, ITER is the only one to have actually progressed to plant construction. Globally, he says, only two or three designs have ever been drafted with a genuine intention to build.
ITER required three years to complete its conceptual design. By contrast, Kyoto Fusioneering achieved the same milestone in just one year from the launch of the FAST project. That speed reflects a growing sense of urgency. Although Japan has long led fusion research, it now faces rapid advances by the United States and China and risks being overtaken without decisive action.
Further compounding the pressure are delays to the ITER program itself. Therefore, knowledge directly applicable to commercial use is now unlikely to emerge before around 2040. As a result, efforts to proceed with power generation demonstrations without waiting for ITER are accelerating worldwide, and Japan cannot afford to be left behind.
China Leads Globally in Research Output
According to Kiyoshi Seko, COO of Kyoto Fusioneering, the US, China, and Europe are all targeting fusion power generation demonstrations in the 2030s. While the US maintains a clear lead in private-sector fundraising, China has emerged as a particularly formidable contender in recent years.
Since 2023, China has pumped approximately ¥1 trillion ($6.5 billion) in public funding into fusion research. Several private fusion companies have also been established, collectively raising hundreds of millions of dollars. Backed by vast financial resources and rapid execution, development is proceeding at a remarkable speed. Although China discloses little publicly, analyses based on US satellite imagery indicate that construction of multiple large-scale fusion-related facilities is already underway.
China's momentum is also evident in academic output. In the 2020s, it has overtaken the United States to become the world's leading producer of research papers on fusion energy.
The Global Fusion Race Accelerates
In the US, the startup Commonwealth Fusion Systems (CFS) plans to construct ARC, a commercial fusion reactor, in Virginia, with operations targeted for the early 2030s. The project drew widespread attention in June when Google signed a contract to purchase electricity generated by ARC.
The momentum is reinforced at the policy level. Back in October 2025, the US Department of Energy released a new national strategy aimed at achieving commercial fusion power generation by the mid-2030s.
Against this backdrop, Seko stressed the urgency of Japan's response. He said that through the FAST project, development would proceed "with a strong sense of speed" to avoid falling behind other countries and to ensure the effort connects directly to Japan's national strategy.
With FAST's overall design now in place and performance requirements for key components and materials clearly defined, collaboration among companies and research institutions is expected to broaden. This, in turn, should accelerate the development of a supply chain capable of supporting a domestic fusion industry.
From Experimental Fusion to Power Generation
The FAST project adopts a tokamak configuration, in which ultra-high-temperature plasma is confined within a donut-shaped vacuum vessel using powerful magnetic fields to induce fusion reactions. This approach, also used by JT-60SA and the ITER, is widely regarded as the leading design for future fusion reactors.
Neither JT-60SA nor ITER, however, is intended to demonstrate electricity generation. JT-60SA focuses on creating and controlling ultra-high-temperature plasma, while ITER aims to extract thermal energy produced by fusion reactions.
FAST takes a different approach. It is designed to demonstrate the entire process, from initiating fusion reactions and extracting heat to converting that energy into electricity. By integrating and validating all the components required for fusion power generation, the project aims to achieve the world's first demonstration of electricity generated by nuclear fusion.
Remote Maintenance as a Core Technology
For fusion power to be commercialized, reactors must be capable of continuous and stable operation. That makes maintenance design a critical consideration. One key component is the blanket, which absorbs the neutrons generated during fusion reactions and therefore requires regular inspection and replacement. Because neutron exposure causes the blanket to become radioactive, however, direct human access is impossible. Developing remote maintenance technologies is therefore essential.
Kenzo Ibano, an assistant professor at Osaka University who contributed to the conceptual design, underscored the point: "Without this, a plant simply cannot function."
As a result, the maintenance system has been positioned as a core demonstration element within the FAST conceptual design.
The team is examining a system in which large, crane-like equipment removes segmented blanket components from the top of the reactor. Detailed design work will now move forward. If this remote maintenance technology can be successfully established, it would represent a world first and could become indispensable for future commercial fusion reactors globally.
Plans are also taking shape for FAST's successor, the commercial reactor FAST2, which is expected to begin operation around 2042. Design work on FAST2 will proceed in parallel with the construction of FAST.
Helical-Type Reactor Achieves First Power Sales Contract
Alongside tokamaks, the helical reactor design originally developed in Japan in the 1950s is also regarded as a promising pathway toward fusion energy. Like tokamaks, it confines high-temperature plasma using powerful magnetic fields. But by employing twisted, helical field configurations, it is believed to enable more stable plasma confinement over longer periods.
Helical Fusion, a startup based in Tokyo and built on expertise inherited from the National Institute for Fusion Science in Toki, Gifu Prefecture, announced in January 2026 that it had signed Japan's first-ever power purchase agreement for electricity generated by fusion energy. The agreement was concluded with Aoki Super, a food supermarket chain operating in Aichi Prefecture.
Under the agreement, Helical Fusion plans to generate electricity using its fusion reactor Helix KANATA and begin selling power in the 2030s.
With Japan's presence strengthening rapidly in both tokamak and helical reactor development, further advances in the global race toward fusion commercialization are increasingly anticipated.
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(Read the article in Japanese.)
Author: Maki Matsuda, The Sankei Shimbun
