Kyoto Fusioneering wins first non-fusion gyrotron order

Quaise’s millimetre wave drilling needs a continuous-operation gyrotron, a duty cycle KF expects fusion power plants to share

(Image courtesy of Quaise Energy)

Kyoto Fusioneering (KF) has taken its first gyrotron order from outside fusion, and the buyer’s requirement is one KF expects fusion power plants to share. Quaise Energy signed in August for a continuous-operation unit to drive millimetre wave drilling into superhot geothermal rock, where the source has to run for as long as the hole advances. KF sees the order as a way to grow gyrotron supply chain capacity before fusion needs it.

Continuous duty sets the Kyoto Fusioneering gyrotron apart

Quaise ablates rock with millimetre waves from a surface gyrotron, and because the source has to run without interruption, the Kyoto Fusioneering gyrotron on order for Quaise is specified and designed for continuous operation.

The requirement is not confined to drilling, since KF expects fusion power plants to need heating that runs continuously. KF describes current research machines as heating plasma in pulses lasting seconds, a duty cycle it ties to today’s devices rather than to the technology, and it describes continuous-duty work for a geothermal customer as directly relevant to fusion.

The order traces back to September 2024, when NEDO, Japan’s national energy and industrial technology R&D funding agency, selected KF for its Deep-Tech Startups Support Program in the Green Transformation field. KF’s project under the programme covers high-power, continuous-operation gyrotrons and power supplies for deep geothermal development, and Quaise is its first commercial outcome.

The Kyoto Fusioneering gyrotron record in fusion

KF designs and builds gyrotrons from 28 GHz to 236 GHz, multi-frequency tubes included, and its fusion deliveries so far take in two dual-frequency units for the UK Atomic Energy Authority’s MAST Upgrade, a 1 MW system for Tokamak Energy’s ST40 and the first of two units for the US Department of Energy’s DIII-D National Fusion Facility. Design work is also complete on a 1.5 to 2 MW class gyrotron for the Wendelstein 7-X stellarator and ASDEX Upgrade at the Max Planck Institute for Plasma Physics.

Growing the gyrotron supply chain ahead of fusion demand

Takashi Imai, Group CEO of KF’s Plasma Heating Group, puts that record in the context of capacity. Gyrotron supply has to grow well beyond its current size, he says, and ahead of fusion demand rather than behind it, with KF investing now and taking commercial work that builds the capability. He calls the Quaise order an important part of that.

Orders from outside fusion serve that aim, according to KF, because they put work through the same design, engineering and quality systems that fusion plants will need, which builds the capability ahead of fusion demand.

Imai’s view of current capacity is echoed in a 2025 paper in Fusion Engineering and Design on KF’s ST40 gyrotron, whose authors include KF’s Keishi Sakamoto and whose introduction describes current gyrotron production capacity as limited, with future fusion devices expected to need significantly larger quantities.

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