Kyoto Fusioneering looks toward a ‘Made in Japan’ approach for nuclear fusion

Ever since the Lawrence Livermore National Laboratory in California achieved ignition in a nuclear fusion experiment in December 2022, a new wave of excitement and hype has grown around the energy source, which has long been tipped to help usher in an era of abundant, clean and safe energy.
That breakthrough in the U.S. has been followed by several more, including some earlier this year. Britain’s JET laboratory, for example, in February produced a record amount of energy through nuclear fusion, which sees atoms smashed together so that they combine and create energy due to their relative weights — the opposite process of conventional nuclear power.
Nuclear fusion is also enjoying high-level political support. In April, the Group of Seven’s energy and environment ministers meeting threw its backing behind the energy source, promising to promote collaboration, establish a working group on the topic and work to develop consistent regulations within the G7.
“It has the potential to provide a lasting solution to the global challenges of climate change and energy security in the future,” the ministers said in a statement. “The successful delivery of fusion energy production could offer major social, environmental, and economic benefits.”
Harnessing fusion, the process that powers the sun and stars, has long been dogged by slow, incremental progress — to the point that there is a recurring joke that the technology is always 30 years away. But against this backdrop and growing moves toward commercialization, startups in the space are targeting much more aggressive timelines, with many saying a fusion plant will deliver power to the grid as early as between 2031 and 2035.
Still, numerous issues remain unsolved, although the nature of them has arguably changed.
For Kiyoshi Seko, director and chief operating officer at startup Kyoto Fusioneering, a key component of this large-scale shift around nuclear fusion is the move from scientific challenges to those related to engineering.
“Now we are in the … engineering challenge phase. How to solve those engineering challenges, that’s our bottleneck,” Seko says, citing the need for certain components to handle temperatures as high as 1,000 degrees Celsius.

Nuclear fusion facilities — which typically work by either using immensely powerful magnets to confine and manipulate plasma, thereby enabling the necessary reaction, or by firing the world’s most powerful lasers at a tiny pellet filled with hydrogen atoms — are mind-bogglingly complex. The numerous devices that they are made up of, such as superconducting coils and fuel systems, are themselves composed of myriad components, each relying on a variety of skills and materials to produce.
In Seko’s eyes, Japan stands ready to provide and develop many of these things. For example, his own firm develops gyrotrons, which are used to heat plasma.
There are many products that only Japanese companies can manufacture given the country’s highly specialized and unique technologies, Seko says. “We are kindly assembling those key suppliers into this fusion ecosystem.”
He points to a special fuel exhaust pump designed to work with tritium, a type of hydrogen atom that is one of the preferred fuels for nuclear fusion. His firm is co-developing the pump with Mikuni Jukogyo by adapting existing tech used for nuclear fission — the process behind conventional nuclear power. That follows a general approach of trying to bring in tech from other industries such as aerospace, or modifying it in order to do so.
And Japan is already a linchpin in certain areas. Seko highlighted the country’s specialism in making the silicon carbide composite materials used for “breeding blankets” — a part of the reactor intended to, among other things, produce more tritium, which is scarce.
“Only one or two Japanese manufacturers can still manufacture this silicon carbide composite, so you cannot find those manufacturers in the U.K. or in the U.S. or in Korea or in Europe,” he says. “So that’s why I’m saying Japan has a pretty unique manufacturing supply chain at the moment.”
Still, collaboration has long been a key facet of nuclear fusion — principally through the ITER project involving the European Union, Japan and several other countries — and it is expected to play an important role in the development of the domestic fusion ecosystem. To that end, industry body Japan Fusion Energy Council, or J-Fusion, was established in March.
Bringing together startups such as Kyoto Fusioneering and Helical Fusion, engineering companies like Mitsubishi Heavy Industries as well as major trading houses such as Sumitomo Corp., the initiative is expected to help build synergies across Japan Inc.
Seko says that once industry or the government is activated, they will make some steady progress and achieve results, and that’s where J-Fusion comes in. “That’s why we wanted to activate Japanese industry as a whole to sustain and harness supply chains toward fusion.
“So although it’s not fast enough, it should be very, very steady progress.”

Another key task for J-Fusion relates to money. Here, Japanese companies have lagged far behind their peers in other countries.
According to a July 2023 report by the Fusion Industry Association, the sector had drawn $6.2 billion in investment, but the companies with $200 million or more in funding — such as Commonwealth Fusion Systems and TAE Technologies, boasting over $2 billion and $1 billion, respectively — are mostly based in the U.S.
Kyoto Fusioneering, meanwhile, had attracted a more humble figure of $91 million by that point.
That reflects broader startup funding trends and the relative strength of venture capital firms in Japan compared with elsewhere, but Seko hopes that J-Fusion will help unlock sources of funding that are more unique to Japan’s ecosystem.
“I think there is some secret sauce in this Japanese startup ecosystem, and that is corporate venture capital under big, big companies … such as trading houses, insurance companies, manufacturing companies, EPC (engineering, procurement and construction) contractors,” Seko says. “There are many, many big companies with a lot of money in their pocket.
“That’s why J-Fusion comes in to take actions from the industrial side, not just waiting for public money,” he adds, while also lamenting that fusion funding in Japan could be much higher given companies’ earnings and the context of the country’s overall spending on energy.
Money should be spent in the private sector “because we cannot wait 30 or 40 or 50 years to make fusion happen. We have to make it within at least 25 or 20 years,” Seko says.
On Wednesday, ITER announced that its fusion reactor won’t begin full-fledged experiments until 2039 at the earliest. That prompted Director General Pietro Barabaschi to warn that, “Fusion cannot arrive in time to solve the problems our planet faces today, and investment in other technologies, known and unknown, is absolutely needed.”
For Seko, what is at stake goes beyond the creation of a clean energy future: It is the building of a new economic powerhouse for Japan. He doesn’t want the country to repeat past mistakes seen in semiconductors and aerospace that prevented these from being major industries, he said, although the government is currently making a major push to regain Japan’s might in the former.
“Now it’s time that we … create another industry in addition to automobiles,” he says.
“Fusion would be a very suitable industry for Japanese manufacturing ecosystems, because we have to have a lot of components and systems, and that should be integrated into one package. So that’s kind of very detailed design, manufacturing, system integration — those are the things Japan was very good at.”