Stellarator Radiation Shielding Patents: Who Leads, Gaps 2026
- Only 11 families total. This is still a niche filing category — activity clustered in a single peak year (2023, 8 filings) rather than a steady climb.
- Filing dropped to zero at the midpoint. 2022 shows no activity before the 2023 spike, and momentum for the leading assignees has since fallen back to zero in the latest year.
- Europe dominates receiving offices. EPO filings (5) outnumber every other route, with PCT, Canada, Germany, Spain and India each holding a single filing.
What this dataset covers
This landscape tracks patent families at the intersection of stellarator and helical fusion reactor design and radiation shielding — neutron shielding, shielding blankets and biological shield claims filed under fusion-reactor and radiation-protection IPC classes. It is a narrow cross-section: 11 published families in total, all classified under G21B (fusion reactors), with 8 also touching G21D (nuclear power plants), showing that shielding claims here are almost always filed alongside broader reactor-architecture disclosures rather than as standalone shielding inventions.
Publication lags filing by roughly 18 months, so any apparent drop in the most recent year is partly an artefact of that lag rather than a real halt in activity. Treat the 2023 peak as the most complete recent signal, and the 2024–2026 tail as still filling in.
Filing trend and technology composition
Two views of the same 11-family dataset: how filings have moved year over year, and which IPC subclasses those filings actually sit in.
A single peak, no sustained ramp
Filings were absent in 2017, stayed flat through the middle of the window, and rose to a peak of 8 in 2023 before falling away again — a pattern consistent with a small number of programmes filing in bursts rather than a continuously growing field.
Shielding claims travel with reactor-architecture claims
Every family in this set is tagged G21B (fusion reactors); 8 of the 11 are also tagged G21D (nuclear power plants). That overlap means most shielding disclosures here are embedded inside broader stellarator or reactor patents rather than filed as dedicated shielding-only applications.
Shares are the percentage of the 11 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Stellarator Radiation Shielding with Eureka
This page is one run against one query. Ask Eureka your own question about stellarator radiation shielding and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited and most representative filing
STELLARATOR MIT PLANAREN FORMGEBUNGSSPULEN (EP4494170B1)
Filed by The Trustees of Princeton University and granted 27 August 2025, this family covers a stellarator design built around planar shaping coils — the same architecture underlying the most-cited record in this set, WO2023178004A1 ("Planar coil stellarator", cited 5 times).Full claim text and family members are rendered in the table above.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | WO2023178004A1 | Planar coil stellarator | 5 |
Citation counts favour older, longer-indexed records — read them as a signal of influence within this small corpus, not as a ranking of current technical importance.
Publication numbers are shown where the record carries one (1 of 1 rows); clicking a row searches Eureka by that number.
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Browse MCP servers →What the filing pattern signals
With only 11 families, small shifts move the picture a great deal — but a few structural signals are visible.
Bursty, not cumulative
The trend runs from zero in 2017 to a peak of 8 in 2023, with a zero reading at the 2022 midpoint. That shape points to a small number of programmes filing in concentrated bursts tied to specific reactor design milestones, not a field building steadily.
Europe is the primary filing venue
EPO accounts for 5 receiving-office filings against single filings each at PCT, Canada, Germany, Spain and India. Anyone tracking freedom-to-operate in this space should watch European prosecution first.
Recent-year activity has stalled across leaders
The two most active assignees in this set — Proxima Fusion and The Trustees of Princeton University — both show zero filings in the latest year, with Proxima Fusion down 100% year-on-year. Given publication lag, this likely understates true recent activity rather than confirming a real stop.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to stellarator radiation shielding, with the prior art for and against each one.
Who is filing, and where the field is still open
Activity in this dataset is split between a university research programme and a private fusion venture, with no other assignee holding more than a handful of families.
The Trustees of Princeton University
Holds the representative EP4494170B1 filing on planar-coil stellarator design and shows recent-year momentum flat at zero, consistent with the publication-lag effect rather than a stopped programme.
Proxima Fusion GmbH
A German private fusion company active in this shielding-adjacent claim space; its latest-year filings dropped to zero, a -100% year-on-year change that should be read against the 18-month publication lag before assuming a real slowdown.
No third major filer yet
Beyond the university programme and Proxima Fusion, the remaining families in this set are spread thinly, with no additional assignee building a discernible filing programme in shielding-specific claims.
| Assignee | Recent year | YoY |
|---|---|---|
| The Trustees of Princeton University | 0 | — |
| PROXIMA FUSION GMBH | 0 | -100% |
| THE TRUSTEES OF PRINCETON UNIVERSITY (100 00) | 0 | — |
Where to take this analysis
This dataset is small enough that a single new filing can shift the ranking — worth re-running the search on a cadence rather than treating any single snapshot as final.
Watch European prosecution closely
With EPO carrying the largest share of receiving-office filings, opposition and examination activity there is the earliest signal of contested claim scope in this field.
Explore EP filings in EurekaTrack the publication-lag window
Filings from 2024 onward are still incomplete in any public dataset; revisit the trend in six to twelve months before drawing conclusions about a slowdown.
Set up a monitoring search in EurekaMap claims against the white space chips
The under-claimed branches identified here are a starting point for freedom-to-operate work, not a conclusion — each needs a dedicated claim-by-claim check.
Run a white space analysis in EurekaCommon questions about stellarator radiation shielding patents
This landscape identifies 11 patent families published between 2015 and mid-2026 that combine stellarator or helical fusion reactor claims with neutron shielding, shielding blanket or biological shield claims under the relevant IPC classes. That is a small, tightly scoped set rather than a broad industry — most fusion-reactor patents do not carry dedicated shielding claims at all. Filing activity peaked at 8 families in 2023, with little activity before or after that year in this dataset.
The Trustees of Princeton University and Proxima Fusion GmbH are the two most active assignees identified in this dataset, with Princeton holding the representative EP4494170B1 planar-coil stellarator filing. Both show zero filings in the latest recorded year, which given an 18-month publication lag likely reflects incomplete recent data rather than a stopped programme. No third assignee in this set has built a comparable filing volume.
The dataset shows filings rising from zero in 2017 and at the 2022 midpoint to a peak of 8 in 2023, then falling in subsequent years. Part of that apparent drop is a data artefact: patent publication typically lags filing by around 18 months, so 2024–2026 filings are still being published and the true recent picture is understated. It should not be read as firm evidence that shielding-specific filing activity has actually stopped.
EP4494170B1, titled "Stellarator mit planaren Formgebungscoils" in its German-language filing, was granted to The Trustees of Princeton University on 27 August 2025. It covers a stellarator architecture built around planar shaping coils, the same design family referenced by WO2023178004A1, the most-cited record in this dataset. Anyone designing a competing coil geometry should review its specific claim scope before finalising a shielding or coil-integration design.
Based on the IPC composition and assignee concentration in this dataset, under-claimed areas include modular blanket segment interfaces for helical (non-axisymmetric) geometries, in-vessel neutron flux monitoring positioned near shielding boundaries, and maintenance-access shielding solutions compatible with non-planar coil sets. These branches show low filing density relative to the core planar-coil shielding claims that dominate the current dataset. A first claim in any of these areas would need to specifically address the geometric irregularity that distinguishes stellarators from tokamaks, since most existing shielding art assumes simpler symmetry.
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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.