Stellarator SMR Patents: Who Leads, Where the Gaps Are 2026
- 27 families total. Filing in this niche is small enough that a handful of continuations from one applicant can move the entire trend line.
- Filing peaked at 18 in 2023, then dropped. with 2022 flat at zero, the growth pattern is a single sharp spike rather than a steady climb.
- Planar coil stellarator designs dominate the most-cited records. four of the five most-cited documents share that exact title, pointing to one design lineage under active prosecution.
What the dataset covers
Stellarator small modular reactor patents sit at the intersection of fusion confinement physics and compact reactor engineering. The 27 patent families captured here run from 2015 through mid-2026, filtered to documents that name a compact, small or high-field stellarator configuration and are classified under fusion-reactor IPC codes. This is a narrow slice of the broader fusion patent space, not a general fusion landscape.
Publication lags filing by roughly eighteen months, so the most recent year in the trend chart understates real filing activity. Treat the 2025-2026 figures as a floor, not a ceiling.
Filing trend and technology composition
Two views of the same 27 families: how filing activity has moved year over year, and which IPC subclasses the claims actually sit in.
A spike, not a trend
Filing was at zero as recently as 2022, then jumped to 18 in 2023 before pulling back. That shape is more consistent with a single applicant's filing campaign than with an industry-wide ramp, and it means any forward projection from this dataset alone should be treated cautiously.
Concentrated in fusion reactor and magnet classes
G21B (fusion reactors) covers all 27 records by definition of the search, but G21D (nuclear power plants) and H01F (magnets, inductors and transformers) each appear in 9 records, showing that claims routinely reach into plant-level integration and magnet engineering rather than staying confined to confinement physics alone. G21G (nuclear transmutation), H05H (plasma and particle accelerators) and H01J (electron and discharge tubes) appear in single digits, marking them as secondary but present claim territory.
Shares are the percentage of the 27 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Stellarator Small Modular Reactor with Eureka
This page is one run against one query. Ask Eureka your own question about stellarator small modular reactor and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited records
System and method for stellarator neutron source
The disclosure covers systems for generating neutrons using a stellarator optimized for fast particle confinement, with the confinement geometry selected from quasi-axisymmetric, quasi-symmetric, quasi-isodynamic or quasi-omnigenous stellarator variants. It also covers methods of generating neutrons using those systems, tying the neutron-source application directly to a specific family of optimized confinement geometries.Filed by The Trustees of Princeton University, published 2023-10-05.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20230317304A1 | System and method for stellarator neutron source | 13 |
| 2 | US20230290525A1 | Planar coil stellarator | 12 |
| 3 | US12009111B2 | Planar coil stellarator | 10 |
| 4 | US12100520B2 | Planar coil stellarator | 7 |
| 5 | US20240153651A1 | Planar coil stellarator | 6 |
| 6 | US20240177874A1 | Planar coil stellarator | 5 |
| 7 | WO2023178004A1 | Planar coil stellarator | 5 |
| 8 | US12451260B2 | Planar coil stellarator including removable field shaping units | 1 |
| 9 | US12537109B2 | Planar coil stellarator | 1 |
| 10 | WO2023178009A1 | System and method for stellarator neutron source | 1 |
Citation counts reflect influence within the searched corpus and skew toward older publications; a 2023 filing with 13 citations has had less time to accumulate them than an equivalent 2018 filing would.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Three read-throughs from the trend and citation data that matter more than the raw counts.
One spike, not a curve
The jump to 18 families in 2023 after a flat 2022 is too sharp to read as gradual industry adoption. It looks like a concentrated filing campaign, likely tied to one or a small number of applicants pursuing a specific design family around that date.
Planar coil stellarator is the reference design
Four of the five most-cited documents in this dataset are titled 'Planar coil stellarator', spanning a published application and multiple granted continuations. That repetition signals a single design lineage being prosecuted deeply rather than five independent inventions.
Claims extend beyond pure confinement physics
A third of the dataset reaches into nuclear power plant integration (G21D) or magnet/inductor engineering (H01F) alongside core fusion-reactor claims (G21B). Filers here are not stopping at confinement geometry; they are claiming plant-level and magnet-level implementation too.
US-centred filing with a thin international tail
The United States receives roughly half the filings in this dataset, with Europe, Canada, India and the PCT route each accounting for a handful. That distribution suggests the technology is still being protected primarily in one jurisdiction rather than filed broadly worldwide.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to stellarator small modular reactor, with the prior art for and against each one.
Assignee landscape
A small applicant base with academic and startup filers both active; recent-year momentum has cooled across the board rather than shifting toward a new entrant.
Princeton-affiliated filings lead the citation table
The Trustees of Princeton University appears behind the most-cited record in the dataset, the stellarator neutron source filing, tying academic fusion research directly into the patent record. Recent-year filing activity from this assignee has dropped to zero, consistent with the broader post-2023 pullback.
Thea Energy shows the sharpest pullback
Thea Energy's filing activity fell to zero in the latest year, a 100% year-over-year decline. Combined with its association with the planar coil stellarator lineage, this points to a company that filed hard around 2023 and has since gone quiet on new applications, at least in what has published so far.
No single assignee dominates the count
With only 27 families spread across academic, corporate and unnamed individual filers, no single organisation holds a commanding share. This is still an open field where a well-drafted first-mover filing in an adjacent sub-area can establish real position.
| Assignee | Recent year | YoY |
|---|---|---|
| The Trustees of Princeton University | 0 | — |
| THEA ENERGY INC | 0 | -100% |
| THE TRUSTEES OF PRINCETON UNIVERSITY (100 00) | 0 | — |
Where to take this
The dataset points to a narrow, recently-active field with one dominant design lineage and several technical branches still open.
Map freedom-to-operate against the planar coil lineage
Before committing engineering resources to a stellarator coil design, run a claim-by-claim comparison against the planar coil stellarator family, since it accounts for the majority of high-citation records here.
Explore claim charts in EurekaWatch for continuations from the 2023 spike
The sharp 2023 filing jump likely has continuation applications still working through prosecution; tracking assignee filing histories directly will surface these before they publish broadly.
Set up assignee tracking in EurekaEvaluate the under-claimed branches for a first filing
Magnet materials, plant integration and neutron shielding around stellarator geometries show thinner direct coverage than the core confinement claims, leaving room for a well-scoped first filing.
Draft a claim strategy in EurekaCommon questions
This dataset identifies 27 patent families published between 2015 and mid-2026 that match stellarator small modular reactor search terms under fusion-reactor IPC classes. That is a small, specialised pool compared to the broader fusion energy patent space, reflecting how early-stage and narrow the compact stellarator sub-field still is. Because publication lags filing by about 18 months, the true number of filed applications is somewhat higher than what has published so far.
The most-cited record in this dataset comes from The Trustees of Princeton University, tying academic fusion research to a specific neutron-source stellarator design. Commercial activity is also visible, particularly around the planar coil stellarator design lineage that accounts for several of the top-cited filings. No single assignee holds a commanding share of the 27 total families, so the field remains open rather than locked up by one player.
The trend data shows filings at zero in 2022, jumping to 18 in 2023, and falling off afterward. A jump that sharp usually reflects a concentrated filing campaign by one or a small number of applicants around a specific design, rather than a steady industry-wide ramp. The apparent drop-off since should be read cautiously, since recent years are understated by the normal 18-month gap between filing and publication.
IPC composition in this dataset shows heavy concentration in core fusion-reactor claims (G21B) with secondary coverage in nuclear power plant integration (G21D) and magnet engineering (H01F). Areas like high-temperature superconducting stellarator magnets, plant-level modular integration, and neutron source shielding show thinner direct coverage relative to core confinement geometry claims. A first filer with a specific, well-drafted claim in one of these adjacent branches could still establish meaningful position given how small the overall dataset is.
Not necessarily. Citation counts inside a search corpus like this one favour older publications simply because they have had more time to accumulate citations, so a 2018 filing will typically out-cite an equally significant 2023 filing. The planar coil stellarator lineage's strong citation showing is a genuine signal of influence, but newer filings in the same dataset should be checked directly for claim scope rather than dismissed for having fewer citations so far.
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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.