Tokamak Miniaturization Patents: Who Leads, Where the Gaps Are 2026
- Filing already peaked. 2018 recorded 36 filings, the high point of the whole window, followed by a decline to a 2022 midpoint of 9 — this is a mature, not accelerating, claim space.
- Magnets dominate the IPC mix. H01F (magnets, inductors and transformers) appears in 44 of 94 families alongside the core G21B fusion-reactor class, confirming that toroidal field coil design is the technical centre of gravity.
- Filing is geographically dispersed. No single receiving office holds a clear majority — the US, UK, China, EPO, WIPO and India all sit within a narrow band of 6 to 17 filings, so no one jurisdiction anchors the field.
What the compact tokamak patent record actually shows
The dataset covers 94 patent families filed against compact tokamak, spherical tokamak and modular fusion device search terms under IPC classes G21B1/00, G21B1/05 and G21B1/11. Filing volume rose sharply into 2018 at 36 families, then fell back to single digits by the 2022 midpoint — a pattern more consistent with an early land-grab around core reactor geometry than with a technology still building momentum. Publication lags filing by roughly 18 months, so the tail end of the trend understates true recent activity, but the shape of the decline predates that lag window.
The technology composition points to where the actual engineering effort sits. Magnets and superconducting coil work (H01F) touch nearly half of all families, alongside meaningful representation in plasma and particle accelerator technique (H05H), solid-state device integration (H10N), and radiation shielding (G21F). That spread signals that miniaturization claims are being built as much around magnet engineering and materials as around reactor vessel geometry itself.
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Filing trend and technology composition
Two views of the same 94-family dataset: filing activity by year, and how records distribute across IPC subclasses beyond the core fusion-reactor classification.
A peak year already behind the field
Filings ran from 7 in 2017 to a peak of 36 in 2018, then declined toward single digits by the 2022 midpoint and toward zero in the most recent (partial) year. Treat the final one to two years as undercounted due to publication lag rather than as a genuine collapse in activity, but the multi-year decline from the 2018 peak is real.
Magnets and plasma technique outweigh reactor-only claims
Every family carries a G21B fusion-reactor classification by search design, but 44 of 94 also carry H01F (magnets, inductors and transformers), and smaller but consistent counts appear in H10N, H05H, H01B, G21F, H01L and C22C — evidence that miniaturization claims are frequently built jointly with magnet, plasma-control or shielding engineering rather than reactor architecture alone.
Shares are the percentage of the 94 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 Miniaturization and Integration with Eureka
This page is one run against one query. Ask Eureka your own question about tokamak fusion reactor miniaturization and integration and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited records in this corpus
US12207384B2 — Top surface wave antenna of spherical Tokamak
Discloses a top surface wave antenna assembly for a spherical tokamak, comprising a feed waveguide, a brim, a series of sub-waveguides arranged at equal intervals on a metal base, and a microwave input port formed by the feed waveguide. The sub-waveguide tops sit at or below the metal base height and follow a rising-line arrangement, positioning the design as a microwave-coupling component for high-power tokamak operation.Filed by Anhui Agricultural University, published 2025-01-21 — one of the more recent grants in the dataset given the 18-month publication lag.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | CN1797613A | 球形托卡马克磁体环向场线圈的中心柱 | 25 |
| 2 | GB2578307A | Wound hts magnet coils | 12 |
| 3 | GB2519827A | Toroidal field coil for use in a fusion reactor | 6 |
| 4 | WO2022219621A1 | An improved fusion nuclear reactor | 5 |
| 5 | GB2558685A | Superconducting magnet | 5 |
| 6 | US20240203609A1 | Fusion nuclear reactor | 4 |
| 7 | GB2562385A | Superconducting magnet for producing part of a substantially toroidal field | 4 |
| 8 | GB2525021A | Efficient compact fusion reactor | 4 |
| 9 | RU2080661C1 | Spherical tokamak vacuum chamber and its manufacturing process | 4 |
| 10 | CN116895388A | 球形托卡马克的等离子体启动方法 | 3 |
Citation counts are drawn from the searched corpus only and skew toward older, earlier-filed records — read them as a signal of influence within this dataset, not as a ranking of current technical importance.
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 pattern means for anyone filing next
Three read-throughs from the filing trend, the IPC spread and the citation table, aimed at where claim space is occupied versus open.
The land-grab already happened
Filing volume peaked in 2018 and has declined through the 2022 midpoint toward zero in the most recent partial year. That is the signature of a field where core reactor-geometry claims were staked early; new entrants now compete on narrower magnet, shielding or integration sub-claims rather than on the base tokamak concept.
Magnet engineering is the real battleground
Nearly half of all families in this set carry a magnets/inductors/transformers classification alongside the core fusion-reactor class. Toroidal field coil design, superconducting winding and magnet-cooling integration are where miniaturization claims are actually being contested, more than reactor vessel shape itself.
Older toroidal-field-coil art still anchors the space
The most-cited record in this dataset concerns the central column of a spherical tokamak's toroidal field coil magnet ring — a structural magnet claim, not a plasma-physics one. Several of the next most-cited records are also wound-coil or toroidal-field-coil patents, reinforcing that coil architecture is the citation backbone of this field.
No single office anchors the field
Receiving-office counts sit in a narrow band from the United States at 17 down to India at 6, with the UK, China, EPO and WIPO all filling in between. Unlike fields with one dominant filing jurisdiction, tokamak miniaturization activity is being prosecuted in parallel across multiple regions at comparable intensity.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to tokamak fusion reactor miniaturization and integration, with the prior art for and against each one.
Who is filing, and where momentum has stalled
Recent-year momentum data shows the named assignees in this set — including Tokamak Energy, universities and national laboratories — recording zero filings in the latest year, several down 100% year-on-year. That does not mean these organisations have stopped working; it is consistent with a field where the last one to two years of publication are still lagging behind actual filing activity.
A quiet latest year across the board
Tokamak Energy, Durham University, the University of Seville, Nanchang University and the UK Atomic Energy Authority all show zero recorded filings in the latest year, with some down 100% year-on-year. Given the 2018 peak and the general decline toward the 2022 midpoint, this looks like continuation of an established trend rather than a sudden exit.
Structural magnet claims carry the most influence
The single most-cited record in this corpus addresses the central column of a spherical tokamak's toroidal field coil magnet ring. Related wound high-temperature-superconductor coil patents also rank among the top-cited records, indicating that coil geometry and winding technique are where prior art is thickest.
Very little formal co-filing
Only two co-assignee pairs appear across all 94 families, both linking the Japan Atomic Energy Research Institute with Mitsubishi Electric and with Mitsubishi Atomic Power Industries respectively. Most filing in this space is done by single-assignee entities rather than joint ventures or research consortia claiming jointly.
| Assignee | Recent year | YoY |
|---|---|---|
| Tokamak Energy Ltd. | 0 | — |
| Nanchang University | 0 | -100% |
| Durham University | 0 | — |
| University of Seville | 0 | -100% |
| ZAMATTIO JACOPO | 0 | — |
| UK Atomic Energy Authority | 0 | — |
| Anhui Agricultural University | 0 | — |
| Institute of Electrical Engineering, Chinese Academy of Sciences | 0 | — |
Where to take this analysis
The trend and IPC data point to specific next checks before committing engineering or legal resource to a filing position in this space.
Map the coil-architecture prior art directly
With toroidal field coil and wound-magnet patents anchoring the top of the citation table, any new magnet-integration filing should be checked against this specific cluster before drafting claims.
Explore coil patents in Eureka →Watch the under-claimed IPC branches
Shielding, alloy composition and cable-insulation subclasses carry far fewer families than the magnet core — these are the branches where a well-drafted first claim still has room.
Run a white-space search in Eureka →Track assignee momentum past the lag window
Zero-filing latest years across multiple named assignees are likely a publication-lag artefact rather than a real stop in R&D; revisit this trend once another 12–18 months of data has cleared.
Set up a filing alert in Eureka →Common questions about tokamak miniaturization patents
This dataset identifies 94 patent families published between 2015 and mid-2026 that match compact tokamak, spherical tokamak or modular fusion device search terms under IPC classes G21B1/00, G21B1/05 and G21B1/11. Filing peaked in 2018 at 36 families and has declined since, with the most recent year understated because publication typically lags filing by around 18 months. Because families rather than raw document counts are used, the figure already accounts for continuation filings and multi-jurisdiction duplicates of the same invention.
The assignee base includes commercial developers such as Tokamak Energy, university groups including Durham University, the University of Seville and Nanchang University, and national programmes such as the UK Atomic Energy Authority and Japan's national atomic energy research institute. No single organisation holds a dominant share of the 94 families; filing is spread across research institutions, universities and a smaller number of commercial fusion developers. Recent-year momentum data shows most of these named assignees recording zero filings in the latest year, consistent with the broader decline from the 2018 peak.
While every family in this dataset carries a core G21B fusion-reactor classification by search design, 44 of 94 also classify under H01F, covering magnets, inductors and transformers — the toroidal field coil and superconducting magnet work central to shrinking a tokamak's footprint. Smaller but consistent activity appears in plasma and particle-accelerator technique (H05H), solid-state device integration (H10N), cable and conductor insulation (H01B), radiation shielding (G21F), semiconductor devices (H01L) and alloy composition (C22C). This spread indicates that miniaturization is being claimed jointly across magnet, materials and integration engineering rather than through reactor-vessel geometry alone.
Based on this dataset, filing activity peaked in 2018 at 36 families and has declined since, reaching a midpoint of 9 in 2022 and trending toward zero in the most recent partial year. That decline should be read cautiously for the final one to two years because publication lags filing by roughly 18 months, meaning recent activity is not yet fully reflected in the record. Taken as a whole, though, the multi-year decline from the 2018 peak predates the lag window and suggests the field's core geometry claims were staked early rather than that activity is still accelerating.
The IPC composition shows comparatively thin filing density in radiation shielding integration (G21F, 7 families), semiconductor-based diagnostics or control (H01L, 6 families), cable and conductor insulation for compact coil assemblies (H01B, 9 families), and alloy composition for reactor components (C22C, just 1 family) relative to the 44-family magnet core. These branches sit adjacent to the dense magnet and coil cluster rather than competing directly with it, which is typically where a first, narrowly drafted claim has the best chance of standing without running into the most-cited prior art.
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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.