Kyoto Fusioneering

What Kyoto Fusioneering does

Kyoto Fusioneering Ltd. is a Japanese fusion energy engineering company founded in October 2019 and headquartered in Tokyo, with R&D operations in Kyoto and subsidiaries in the UK, US, Germany, and Canada. The company develops and commercializes industrial-grade peripheral subsystems for magnetic-confinement fusion power plants — specifically plasma heating systems based on gyrotron technology, fusion blanket and thermal cycle systems including its proprietary SCYLLA® Self-Cooled Yuryo Lithium-Lead Advanced blanket concept, and complete tritium fuel cycle subsystems (exhaust, isotope separation, impurity removal, ZrCo storage, palladium diffusers, VST tritium extraction). Its technology base is anchored by approximately 800 years of cumulative fusion R&D experience across its engineering staff and validated through integrated test facilities including UNITY-1 in Kumiyama, Kyoto (operational since September 2023) and UNITY-2 at Chalk River, Canada (under construction via the Fusion Fuel Cycles Inc. joint venture with Canadian Nuclear Laboratories, target mid-2026 operations). Notable technical milestones include the world-first demonstration of a single gyrotron producing five output frequencies (104/137/170/203/236 GHz) with QST in July 2024 and a 3-second 1 MW-class output at 35 GHz demonstrated with NIFS, University of Tsukuba, UKAEA, and Canon Electron Tubes & Devices in January 2024.

The company serves three primary customer segments: public fusion research institutions and national laboratories (UKAEA, QST, NIFS, ORNL, INL, PPPL, DOE) which purchase engineered subsystems and contract R&D services; private fusion energy developers (General Atomics, Realta Fusion, Starlight Engine) which procure gyrotrons and blanket components; and industrial component manufacturers (Canon Electron Tubes & Devices, JASTEC, Fujikura, Kyocera, MORESCO, Shimadzu, Mikuni Jukogyo) with which KF co-develops and resells fusion-qualified components. KF operates a fabless manufacturing model with 50+ Japanese suppliers, transitioning to dedicated in-house gyrotron production at the KF Shiga Innovation Factory (Takashima City, operations from autumn 2026).

Kyoto Fusioneering generates revenue through quote-based hardware sales of gyrotron systems and other fusion plant components, multi-year engineering services and R&D contracts (UKIFS blanket manufacturing demonstrator, UKAEA HTS Stage 1, DOE/ORNL UNITY-3 partnership work, BMBF and NEDO grants), revenue participation through the FFC joint venture, and resale of co-developed components into the global fusion supply chain. Pricing is project-by-project and not publicly disclosed. The company has raised over ¥24B (~$155M+) cumulatively across multiple Series C closes and extensions between 2023 and 2025, with strategic and institutional investors including In-Q-Tel, Nichicon Corporation, Marubeni Corporation, JIC Venture Growth Investments, JAFCO, and others. The company is privately held, with five-country operations, and serves as project leader of the FAST fusion power generation demonstration project targeting the 2030s.

Name

Kyoto Fusioneering

Legal name

Kyoto Fusioneering Ltd.

Website

https://kyotofusioneering.com

Company type

Private

Founded year

2019

Operating status

Operating

Headcount range

51–100 employees

Short description

Kyoto Fusioneering is a Japanese fusion energy engineering company that develops industrial-grade peripheral subsystems — gyrotron plasma heating, fusion blanket/thermal cycle, and tritium fuel cycle systems — serving fusion research institutions and private fusion developers globally.

Ownership category

akta.pro rank

Product category

Fusion Energy Engineering Systems

NAICS

Power Boiler and Heat Exchanger Manufacturing (332410), Industrial Process Furnace and Oven Manufacturing (333994)

SIC

X-Ray Apparatus & Tubes & Related Irradiation Apparatus (3844), Industrial Process Furnaces & Ovens (3567)

akta.pro primary industry

Reactor Vessel, Internals & Primary Circuit Components (RPV, piping, pumps, valves) (EUAKADAE)

akta.pro secondary industry

Advanced & Non‑LWR Fuel Manufacturing (TRISO, metallic fuels, HALEU fuels) (EUAKACAG)

Keywords

• Fusion plant engineering
• Gyrotron heating systems
• Fusion fuel cycle
• Fusion blanket systems
• Fusion balance of plant

Headquarters

HQ city

Tokyo

HQ country

Japan

HQ region

Asia

Offices11 records

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

Technology or R&D, Personnel, Supply Chain, Infrastructure, Operations, Marketing or Sales

Revenue model

1. Gyrotron system sales: Sale of gyrotron heating systems as engineered product packages (gyrotron body + superconducting magnet + power supplies + support systems) to fusion research institutions and private developers. Builds on QST-licensed gyrotron technology. Customers include UKAEA, GA and overseas fusion startups.
2. Engineering services & R&D contracts: Contract R&D and engineering services for fusion subsystems (HTS magnets, fuel cycle, blanket components, additive manufacturing). Includes fixed-price contracts such as UKIFS STEP blanket manufacturing demonstrator, UKAEA HTS coil programme (Stage 1), and DOE partnership.
3. Joint venture revenue share (Fusion Fuel Cycles Inc.): Revenue participation through FFC joint venture with Canadian Nuclear Laboratories, focused on fuel cycle system design and sale of UNITY-2-related services to fusion developers worldwide.
4. Product resale / supply distribution: Resale of co-developed radiation-resistant lubricants (MORESCO), turbo molecular pumps (Mikuni Jukogyo/Shimadzu), ceramics (Kyocera) and other fusion plant components into the global fusion supply chain, leveraging KF's international network.
5. Public R&D grants and subsidies: Receipt of public-sector R&D funding from NEDO (Japan GX Deep-Tech Startup Support Program for deep geothermal application of gyrotrons), Germany's BMBF (Funding Program Fusion 2040), and related programs.

Pricing tiers

Go-to-market motion1 record

Distribution channels4 records

Marketing channels9 records

Core offering

Kyoto Fusioneering develops and sells engineered peripheral subsystems for fusion energy plants, with three product pillars: (1) gyrotron-based plasma heating systems covering frequencies from 28 GHz to 236 GHz, (2) fusion fuel cycle systems covering tritium extraction, isotope separation, storage, and recovery, and (3) fusion blanket and thermal cycle systems (anchored by the proprietary SCYLLA© LiPb blanket) targeting ~1000°C operation. The company also operates integrated test facilities (UNITY-1 in Japan and UNITY-2 in Canada via a joint venture) to validate subsystem performance for fusion developers and research institutions.

Product overview

Kyoto Fusioneering offers a unified engineering platform organized around three core fusion energy plant subsystems — the Plasma Heating System (Gyrotron System), the Fusion Fuel Cycle System, and the Fusion Blanket and Thermal Cycle System (anchored by the proprietary SCYLLA© blanket concept) — collectively supporting the design, development, and integration of fusion peripheral technologies. The company's portfolio is brought together through its UNITY integrated testing program, comprising UNITY-1 at the Kyoto Research Center (validating thermal-cycle and power-generation technology) and UNITY-2 in Chalk River, Canada via the Fusion Fuel Cycles Inc. (FFC) joint venture (validating D-T fuel cycle systems). Manufacturing is anchored by the new KF Shiga Innovation Factory for gyrotron system production. Complementary offerings include downloadable White Papers and knowledge resources that support global client engagement, including with the UKAEA STEP program, the FAST project, the U.S. DOE UNITY-3 partnership, and the Oak Ridge National Laboratory collaboration.

Differentiator

Problem solved

Functional benefit

Products and services

• Plasma Heating System (Gyrotron System) High-power gyrotron systems for heating plasma in magnetic confinement fusion reactors, covering frequencies from 28 GHz low band up to 236 GHz high band. Delivered as integrated systems including high-voltage power supplies, superconducting magnets, mounting frames, manifolds, oil tanks, and instrumentation panels. Shipped as engineered product packages to fusion research institutions and private fusion developers.
• Fusion Fuel Cycle System Systems for extracting, purifying, and recirculating tritium and deuterium fuel from fusion reactor exhaust, including exhaust systems (divertors, pumps, DIR systems), impurity removal, isotope separation, ZrCo-based hydrogen storage, palladium diffusers, proton conductor pumps, water detritiation systems (WDS), and tritium measurement devices.
• Fusion Blanket and Thermal Cycle System System for capturing heat from fusion plasma and converting it to electricity, including advanced blankets (such as the SCYLLA© design), low-activation SiC composite materials, liquid metal loops (LiPb, Li), molten salt loops (FLiBe), advanced helium heat exchangers, and power generation cycles targeting ~1000°C operation.
• UNITY-1 Integrated Test Plant World's first integrated test plant to demonstrate fusion energy power generation technology in a simulated fusion environment, located at the Kyoto Research Center in Kumiyama, Kyoto. Uses magnetic field environment with electric heaters to simulate energy transfer from plasma blanket through liquid metal loop, advanced heat exchangers, and power generation system. Includes VST (Vacuum Sieve Tray) for hydrogen isotope separation testing.
• UNITY-2 Integrated Test Facility Integrated fusion fuel cycle test facility being built in Chalk River, Ontario, Canada, led by Fusion Fuel Cycles Inc. (FFC), the joint venture with Canadian Nuclear Laboratories. Will demonstrate D-T fuel cycle including tritium extraction, storage, exhaust systems, and pumps, targeting operation by mid-2026. Open platform for global fusion energy institutions and companies to advance tritium handling technology.
• SCYLLA© Blanket (Self-Cooled Yuryo Lithium-Lead Advanced) Proprietary fusion blanket concept using lithium-lead (LiPb) alloy as both coolant and tritium breeder, designed for high-temperature operation around 1000°C with high thermal efficiency and low-activation SiC composite materials. Forms the basis of the breeding blanket technology for UNITY-3 and FAST.

Quantifiable outcome

• World's first 1-MW class output for 3 seconds at 35 GHz gyrotron frequency
• +5 more outcomes

Named customers10 records

Segments5 records

Ideal customer profiles4 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature7 records

Partnerships

31 partnerships are on record, tiered flagship, strategic and tactical.

• General AtomicsflagshipStrategic or Co-development Partner · 13 June 2026Multi-pronged collaboration: General Atomics is a customer (new orders for fusion plant components), a BCTF public-private partner (with DOE, INL, KF, and UC San Diego), and a $20M investor in Fusion Fuel Cycles Inc. KF is leveraging GA's Magnet Technologies Center infrastructure to accelerate fusion blanket test facility development timelines.
• Idaho National Laboratory (INL)strategicStrategic or Co-development Partner · 13 June 2026Public-private partner in the General Atomics-led BCTF (Fusion Blanket Component Test Facility) project along with DOE and UC San Diego. Also a partner in KF's INFUSE programme joint research for enriched lithium-lead samples for neutron irradiation testing at the NRAD reactor.
• University of California San Diego (UC San Diego)strategicStrategic or Co-development Partner · 11 June 2026Academic partner in the public-private BCTF collaboration with General Atomics, DOE, and Idaho National Laboratory.
• U.S. Department of Energy & Japan's MEXT (Genesis Mission)flagshipStrategic or Co-development Partner · 4 June 2026Kyoto Fusioneering is developing fusion infrastructure in the United States through the $1 billion US-Japan Genesis Mission AI partnership, which involves DOE and Japan's Ministry of Education, Culture, Sports, Science and Technology investing $500 million each over five years across AI, quantum, fusion, and semiconductors.
• Tokyo Metropolitan GovernmentstrategicStrategic or Co-development Partner · 24 March 2026Selected Kyoto Fusioneering for the SusHi Tech Global Growth Acceleration Program to contribute to forming Tokyo's fusion industry ecosystem and establishing social implementation of fusion energy.
• Realta FusionstrategicStrategic or Co-development Partner · 16 March 2026Bilateral strategic partnership announced March 16, 2026, to accelerate global commercialization of fusion energy. Covers joint development of plasma heating systems for magnetic mirror fusion machines, mirror-based neutron sources, and blanket/fuel cycle technology. Realta is purchasing gyrotrons from KF for installation at its planned Wisconsin research facility. Includes coordinated government engagement and supply chain development.
• UK Industrial Fusion Solutions Ltd. (UKIFS)flagshipStrategic or Co-development Partner · 24 February 2026UKIFS awarded Kyoto Fusioneering UK its first contract to develop an advanced manufacturing demonstrator for future fusion blanket technologies. The project, led by KF in collaboration with Alloyed Ltd and TWI Ltd, uses advanced additive manufacturing and welding techniques to produce a representative module for structural evaluation. Aligns with the UK's £2.5 billion fusion sector funding announced in June 2025 Spending Review.
• Alloyed LtdtacticalImplementation/ SI/ Consulting Partner · 24 February 2026UK-based partner collaborating with Kyoto Fusioneering UK and TWI Ltd on the UKIFS advanced manufacturing demonstrator for fusion blanket technologies. Brings advanced additive manufacturing capabilities.
• TWI LtdtacticalImplementation/ SI/ Consulting Partner · 24 February 2026UK-based partner collaborating with Kyoto Fusioneering UK and Alloyed Ltd on the UKIFS advanced manufacturing demonstrator for fusion blanket technologies. Brings advanced welding expertise.
• Oak Ridge National Laboratory (ORNL)flagshipStrategic or Co-development Partner · 30 January 2026Cross-border public-private collaboration announced January 30, 2026, to develop technology for accelerating commercial fusion energy deployment through the creation of the UNITY-3 breeding blanket test facility. Leverages ORNL's expertise in supercomputing, advanced manufacturing, materials science, and fusion research, and complements KF's existing UNITY test facilities.
• U.S. Department of Energy (DOE)flagshipStrategic or Co-development Partner · 29 January 2026Strategic partnership to build critical fusion infrastructure and accelerate deployment of commercial fusion power. Centerpiece is joint development of UNITY-3, a next-generation breeding blanket test facility at Oak Ridge National Laboratory, with strong industry backing from ten partners including seven leading U.S. fusion development programmes. KF's global testing facilities are integrated with DOE's national laboratory system.
• Shimadzu CorporationstrategicStrategic or Co-development Partner · 3 December 2025Joint development with Kyoto Fusioneering of a turbo molecular pump prototype designed for operation in tritium environments, supporting fusion fuel cycle systems.
• Kyocera CorporationstrategicStrategic or Co-development Partner · 10 September 2025Joint development agreement with Kyoto Fusioneering for ceramics components for fusion (nuclear fusion) energy plants.
• MORESCO CorporationstrategicStrategic or Co-development Partner · 26 May 2025Strategic business alliance for development and sale of radiation-resistant lubricants for fusion power plants. KF will conduct direct evaluation of MORESCO's high-performance lubricants on its equipment and resell them globally via its international network.
• Kyoto UniversityflagshipStrategic or Co-development Partner · 19 May 2025Multi-party joint research on FAST project plasma design. Kyoto University brings decades of theoretical research on magnetically confined fusion plasma to optimize plasma shape, coil placement, conductor wall placement, pressure/current distribution for the FAST power-generation tokamak reactor. Associate Professor Akiyuki Matsuyama leads the research.
• Fujikura Ltd.strategicStrategic or Co-development Partner · 19 May 2025Co-development partner for the UKAEA STEP programme HTS magnet research advancement project (Stage 1). Fujikura supplied world-leading HTS wire technology while KF contributed fusion plant engineering expertise. Successfully completed Stage 1 contract in June 2025, including manufacture of 7 prototype HTS coils and validation of measured vs predicted energization characteristics.
• Nagoya UniversitystrategicStrategic or Co-development Partner · 15 May 2025Joint research on FAST project plasma design, led by Professor Takaaki Fujita of the Graduate School of Engineering who led JT-60U research achieving world-top effective energy gain Q>1 and plasma design for JT-60SA. Brings plasma physics and tokamak design expertise.
• University of TokyoflagshipStrategic or Co-development Partner · 25 April 2025Co-partner in the "Fusion System Design" social collaboration course established May 1, 2025, led by Professor Akira Ejiri of the Graduate School of Frontier Sciences, alongside seven private companies including Starlight Engine, J-Power, JGC, Furukawa Electric, Fujikura and Marubeni. Focuses on academic foundations for fusion plant design, regulatory standards, and talent development.
• Kyushu UniversitystrategicStrategic or Co-development Partner · 24 April 2025Joint research on FAST project device design, led by Professor Kazuaki Hanada of the Research Institute for Applied Mechanics, who led the design, construction, and operation of Asia's largest spherical tokamak QUEST. Brings plasma-wall interaction expertise and historical QUEST experimental data to FAST design.
• Tohoku UniversitystrategicStrategic or Co-development Partner · 14 April 2025Joint research agreement on tritium and radioactive byproduct evaluation and handling for fusion plant operation. Led by Professor Yuji Hatano of the Graduate School of Engineering. Activities include tritium measurement methods, material durability assessment under irradiation/tritium environment, and waste management policy. Supports the FAST project target of 2030s power generation demonstration.
• Oxford SigmastrategicStrategic or Co-development Partner · 16 December 2024Collaborative research with Oxford Sigma and the UK STEP programme, published in Fusion Engineering and Design, exploring novel configurations and materials for tritium breeding in spherical tokamaks with limited space.
• Karlsruhe Institute of Technology (KIT)strategicStrategic or Co-development Partner · 4 December 2024Joint partner in the KaLiAS lithium enrichment research project with Kyoto Fusioneering Europe GmbH and Argentum Vivum Solutions GmbH. Selected for German BMBF Funding Program Fusion 2040 grant.
• Starlight Engine Co., Ltd.flagshipStrategic or Co-development Partner · 12 November 2024Industry partner and FAST project leader (Fusion by Advanced Superconducting Tokamak), targeting D-T fusion power generation (50–100 MW, 1000-second discharge) in the 2030s. Kyoto Fusioneering contributes Fusion Heat Cycle System, Fusion Fuel Cycle System and other plant engineering technology. Co-founded by FAST CEO Seko Kei (also Kyoto Fusioneering President).
• Canadian Nuclear Laboratories (CNL)flagshipStrategic or Co-development Partner · 2 May 2024Joint venture partner with Kyoto Fusioneering in Fusion Fuel Cycles Inc. (FFC), established May 2, 2024, to design and deliver integrated fusion fuel cycle systems. CNL hosts the UNITY-2 test facility at its Chalk River site in Ontario. Brings CANDU-reactor tritium handling experience; KF brings fusion plant engineering expertise.
• University of TsukubastrategicStrategic or Co-development Partner · 12 March 2024Special joint research agreement on plasma heating with the Plasma Research Center (Director: Professor Mizuki Sakamoto). Aims to advance technical maturity of KF's gyrotron systems including low-frequency gyrotron continuous operation and high-power output development. Co-developed the world-leading 3-second 1MW-class output at 35 GHz in January 2024.
• Mikuni Jukogyo Co., Ltd. (三國重工業)strategicStrategic or Co-development Partner · 18 December 2023Co-developed high-performance fuel exhaust vacuum pumps for fusion plants with Kyoto Fusioneering, leveraging Mikuni's vacuum pump expertise. The pump features high durability against radioactive materials and high exhaust performance for light elements like hydrogen.
• National Institute for Quantum Science and Technology (QST)flagshipStrategic or Co-development PartnerLong-standing joint research partner that originated much of Japan's gyrotron technology base. QST completed eight gyrotrons for the international ITER project in 2021; KF builds on QST technology to develop commercial multi-frequency gyrotrons. Jointly demonstrated the world-first 5-frequency single gyrotron in July 2024.
• National Institute for Fusion Science (NIFS)strategicStrategic or Co-development PartnerJoint research partner for high-power long-pulse gyrotron development. NIFS provided the test facilities and expertise (Associate Professor Masaki Nishiura's ECH group) used to demonstrate the 3-second 1MW-class output at 35 GHz in January 2024.
• Canon Electron Tubes & Devices Co., Ltd.strategicStrategic or Co-development PartnerManufacturing partner responsible for production of KF's gyrotrons, including the 35 GHz low-frequency gyrotron and the 5-frequency gyrotron developed with QST. Wide-ranging collaborative relationship spanning product development to product management and quality assurance.
• JASTEC (Japan Superconductor Technology Inc.)tacticalStrategic or Co-development PartnerManufacturer of the 9.5T high-magnetic-field superconducting coil used in KF's world-first 236 GHz gyrotron.
• Kansai Electric Power Co., Inc.tacticalStrategic or Co-development PartnerProvided cooperation for KF's gyrotron experimental implementation, including facility support during the 5-frequency gyrotron demonstration.

Scale indicators12 records

Recent moves10 records

Expansion highlights7 records

Direct peers

• Realta Fusion: US magnetic-mirror fusion spinout from UW-Madison, already a confirmed KF gyrotron customer with a Wisconsin research facility under development. Comparable because it is a direct paying customer for KF's plasma heating systems and a co-developer on blanket/fuel cycle technology.
• General Fusion: Magnetized-target fusion developer with deep Canadian nuclear engineering DNA (partnered with CNL). Directly comparable because it is both a potential customer for fusion fuel cycle and blanket subsystems (the same engineering stack KF sells) and a fellow engineering-services-oriented fusion company operating in the same North American public-private partnership ecosystem.
• Stellant Systems (formerly CPI TMD): US-based manufacturer of high-power microwave and millimeter-wave devices including gyrotrons for fusion (supplier to ITER, DIII-D, KSTAR). The most direct technical competitor to KF's gyrotron franchise, particularly for the higher-frequency HTS-reactor market KF is targeting with its 236 GHz system.

Emerging players

• Type One Energy: US stellarator fusion developer building toward an Infinity Two prototype. Comparable as a private fusion startup whose peripheral subsystems (plasma heating, blankets, tritium handling) overlap with KF's portfolio and whose mid-2030s commercialization timeline places it in a similar pre-commercial risk class.

Broad incumbents

• Thales (Electron Devices): European supplier of high-power gyrotrons for ITER, TCV and other major tokamaks. Comparable as an incumbent gyrotron manufacturer whose installed base and ITER track record make it the most credible established competitor to KF in plasma heating subsystems for European and global fusion programs.
• TAE Technologies: US field-reversed configuration fusion developer pursuing a commercial p-B11 reactor. Comparable to KF as a large, well-capitalized private fusion customer/competitor for plasma heating subsystems and engineering services, with overlapping need for integrated test infrastructure.
• Helion Energy: US pulsed FRC fusion developer targeting first electricity to grid by 2028 with Microsoft as anchor customer. Comparable as a private fusion developer with a different reactor concept whose peripheral-system requirements (plasma heating, thermal cycle, fuel handling) overlap with KF's product portfolio and could make it a future customer.
• Commonwealth Fusion Systems: Largest private fusion developer (SPARC/ARC tokamak program, raised $2B+). Comparable because it is both a potential large-volume KF customer for gyrotrons/blanket/fuel-cycle subsystems and a competitor if it insources balance-of-plant engineering, as it has signaled in some areas.
• Tokamak Energy: UK-based spherical tokamak developer (ST80-HTS, ST-E1) and one of the most advanced private fusion companies. Comparable to KF because it sits at the intersection of plasma heating demand (where KF is the de facto supplier to MAST Upgrade/STEP-adjacent programs) and in-house engineering on HTS magnets and tritium systems where it could become a vertical-integration threat.

Others

• Princeton Stellarators / Princeton Plasma Physics Laboratory (PPPL): US Department of Energy national laboratory running major fusion experimental facilities (NSTX-U, MRX) and an existing KF INFUSE research partner. Comparable because PPPL operates fusion test infrastructure (analogous to UNITY-1) and is both a research collaborator and a potential alternative supplier of plasma heating expertise to global fusion developers.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat5 records

Key risks6 records

Key highlights6 records

Customer concentration

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Revenue estimate

Valuation estimate

Number of profiles

Profiles8 records

Subsidiaries4 records

Funding overview

Funding rounds13 records

Investors38 records

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M&A

Investments

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Frequently asked questions about Kyoto Fusioneering