Tokamak Fusion Patents: Who Leads, Where the Gaps Are 2026
- Filing peaked in 2024 at 39 records then the trend has not sustained that pace — this looks more like a funding-driven filing wave than a steady climb.
- China now files more than double the United States 119 receiving-office filings against 55, with the gap concentrated in the last three years.
- The two most-cited patents are both pre-2020 US filings on toroidal plasma merging and pulsed ion-beam heating — foundational claims that newer entrants still have to work around.
Filing growth compares 2021 (14 records) with 2024 (39) — a three-year span. 2024 is the most recent year we treat as complete: publication lags filing by roughly 18 months, so 2025 onwards are still filling in and any growth rate that ends there would understate the field. Top-5 share is the combined record count of the five largest assignees divided by all 270 records in scope (CR5), not by the ranked leaders only.
What the tokamak patent record actually covers
This landscape draws on 270 patent families published between 2015 and mid-2026 that claim tokamak or magnetic-confinement fusion technology, filtered to records touching superconducting magnet, plasma confinement or plasma heating subject matter under G21B and H05H. The corpus spans reactor architecture, magnet systems, plasma diagnostics and the digital-control layer that increasingly sits around a tokamak build.
Because publication lags filing by roughly eighteen months, the 2025–2026 figures in any trend line understate real filing activity; treat the most recent one or two years as a floor, not a ceiling.
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Filing trend and technology composition
Two views of the same 270-family corpus: how filing volume has moved year over year, and where those filings sit across the IPC classification tree.
A filing wave, not yet a sustained curve
Annual filings rose from 7 in 2017 to a peak of 39 in 2024, passing through 13 at the 2022 midpoint. The climb from midpoint to peak is steep, but the drop-off implied by the 2026 partial-year figure of 12 suggests the wave crested rather than continued — consistent with a small number of well-funded programmes filing in clusters rather than a broad, steady base of activity.
Reactor and plasma classes dominate; the control layer is thin
G21B (fusion reactors) covers 227 of 270 records and H05H (plasma and particle accelerators) covers 69, confirming this corpus is core reactor and plasma-physics IP rather than adjacent tooling. Magnet technology (H01F, 30 records) is a distinct and separately claimable layer. Digital data processing (G06F, 13 records) and measurement classes (G01R, G01T) are comparatively thin — control software and diagnostics are claimed far less densely than the physical reactor and magnet systems around them.
Shares are the percentage of the 270 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Tokamak Fusion Reactor Fusion Technology with Eureka
This page is one run against one query. Ask Eureka your own question about tokamak fusion reactor fusion technology and every answer comes back with the patent numbers behind it.
Try EurekaThe foundational claims everyone else files around
Magnetic confinement fusion reactor (US20240290505A1)
Filed by Hefei Institutes of Physical Science, Chinese Academy of Sciences, this application claims a full reactor host system built around a superconducting magnet system with distinct central solenoid, poloidal field and toroidal field magnets, plus a Dewar, cold shield, vacuum chamber, divertor, blanket and remote maintenance systems around it. It is a systems-level claim rather than a narrow component claim.Filed 2024-08-29 — recent enough that its full prosecution history and any continuations are still developing.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US4274919A | Systems for merging of toroidal plasmas | 138 |
| 2 | US4548782A | Tokamak plasma heating with intense, pulsed ion beams | 107 |
| 3 | CN117457240A | 一种磁约束聚变反应堆 | 34 |
| 4 | US5353314A | Electric field divertor plasma pump | 34 |
| 5 | US4330864A | Double layer field shaping systems for toroidal plasmas | 34 |
| 6 | US5198181A | Stabilizing plasma in thermonuclear fusion reactions using resonant low level electromagnetic fields | 32 |
| 7 | US3663361A | Nuclear fusion device of the air-core tokamak type | 31 |
| 8 | US4749540A | Demountable tokamak fusion core | 30 |
| 9 | US20240290505A1 | Magnetic confinement fusion reactor | 29 |
| 10 | CN104409107A | 一种超导磁约束聚变堆快热中子耦合水冷产氚固态包层 | 29 |
Citation counts inside this corpus favour older filings that have had more years to accumulate citations — read them as a measure of influence on subsequent filers, not as a signal that the underlying claims are still the state of the art.
Patent titles are shown in the language they were filed in, not translated, so that each record stays verifiable against the original filing — a translated title will not match in Eureka or in any national register. Each row carries its publication number; clicking a row searches Eureka by that number.
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Browse MCP servers →What the numbers mean for a filing decision
Three patterns stand out once volume, geography and citation data are read together.
China's filing office lead is recent, not historical
China accounts for 119 of the tracked receiving-office filings against 55 for the United States, with WIPO, Japan, Europe and the UK each in the 15-20 range. Given the 2024 peak year, this gap is concentrated in recent filings rather than built up steadily since 2015.
The oldest patents still anchor the citation graph
The two most-cited records in the corpus — on toroidal plasma merging and pulsed ion-beam heating — both predate 2015 and sit well outside the current filing window, yet they remain the most-referenced prior art for newer plasma-confinement and heating claims.
Co-filing is rare and mostly within-country
Only 10 co-assignee pairs appear across 270 families, and the strongest of them links a commercial fusion venture with a university research partner. Cross-border co-filing between the leading Chinese institutes and Western programmes is not visible in this data.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to tokamak fusion reactor fusion technology, with the prior art for and against each one.
Who is filing, and who has slowed down
Momentum data tells a different story from raw volume: several of the most active historical filers show sharp year-over-year declines in the latest tracked year.
Hefei Institutes of Physical Science
Filed 2 records in the latest tracked year, down from a higher prior-year base — still active, and the assignee behind the representative full-reactor filing in this corpus, but cooling from its recent peak.
Tokamak Energy and Commonwealth Fusion Systems
Both show zero filings in the latest tracked year against a non-zero prior year, a pattern consistent with publication lag rather than a stop in R&D — but it means their most recent claim activity is not yet visible in this data.
Southwestern Institute of Physics and USTC
Each dropped to a single filing in the latest year from a markedly higher prior base, part of a broader pattern across Chinese academic assignees of front-loaded filing rather than sustained annual output.
| Assignee | Recent year | YoY |
|---|---|---|
| Hefei Institutes of Physical Science, Chinese Academy of Sciences | 2 | -33% |
| Southwestern Institute of Physics | 1 | -83% |
| University of Science and Technology of China | 1 | -83% |
| Dalian University of Technology | 1 | 0% |
| Tokamak Energy Ltd. | 0 | -100% |
| Commonwealth Fusion Systems | 0 | -100% |
| Toshiba Corporation | 0 | — |
| Massachusetts Institute of Technology (MIT) | 0 | — |
Where to take this analysis
The landscape above answers what has been filed. The next questions are what specifically blocks a given design, and where the open claim space actually is.
Check freedom-to-operate against the top-cited claims
Before committing to a reactor or magnet architecture, run the specific claim language of the most-cited patents against your design rather than relying on filing counts alone.
Explore in Eureka →Track the assignees still filing, not just the largest portfolios
Momentum data shows some of the largest historical filers have gone quiet in the most recent tracked year; watch who is still filing now, not who filed the most historically.
Explore in Eureka →Map the under-claimed control and diagnostics layer
Software control, quench protection and remote maintenance sit well below reactor and magnet claim density — a narrower search here may surface genuinely open space.
Explore in Eureka →Common questions about tokamak fusion patents
Filing activity in this corpus is led by Chinese state research institutes, particularly Hefei Institutes of Physical Science, Chinese Academy of Sciences, alongside academic filers such as the Southwestern Institute of Physics and the University of Science and Technology of China. Commercial ventures including Tokamak Energy and Commonwealth Fusion Systems also appear, often filing jointly with university partners such as MIT. No single assignee holds a dominant share of the 270 tracked families — filing is spread across a moderately long list of institutes, universities and companies rather than concentrated in one or two portfolios.
The corpus shows filings climbing from 7 in 2017 to a peak of 39 in 2024, which lines up with a period of significant public and private fusion investment worldwide, including new commercial ventures and expanded national programme funding. The apparent decline after 2024 should be read cautiously: because publication typically lags filing by about eighteen months, 2025 and 2026 figures are undercounted in this data and will likely revise upward as more records publish. It is too early to call 2024 a definitive peak rather than a reporting artefact.
This landscape is scoped specifically to magnetic confinement fusion — tokamak-style reactors that use superconducting magnet systems to contain plasma — and does not cover inertial confinement or other fusion approaches. Within magnetic confinement, the patent record splits between core reactor architecture (G21B, 227 records), plasma and particle physics (H05H, 69 records) and magnet technology (H01F, 30 records), with reactor-level claims dominating over any single component technology.
The classification data shows a sharp drop-off outside the core reactor, plasma and magnet classes: digital control systems (G06F), radiation shielding (G21F) and measurement/diagnostics (G01R, G01T) each account for well under 15 records apiece against 227 for the core reactor class. Divertor heat-flux management, real-time plasma control software, and remote maintenance robotics for reactor vessels are all represented in the corpus but at low density relative to the physical reactor and magnet claims around them, suggesting these are areas where claim space is less occupied.
By receiving-office filing count, yes — China accounts for 119 filings in this corpus against 55 for the United States, with WIPO, Japan, Europe and the UK each contributing 15-20. This reflects where applications were filed, not necessarily where the underlying research originated, and a single family can file in multiple offices. The gap has widened in recent years alongside China's broader increase in fusion-related public research funding, but the most-cited foundational patents in the space remain US filings from before 2015.
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.