Nuclear Safety Patents: Top Companies & Filing Trends 2026
- Concentrated at the top. the five most active filers account for 34.4% of all 1,110 records in scope, and the ten most active for 47.3% — a long tail of single- and few-filing entrants fills the rest.
- Filing has pulled back from its peak. activity peaked at 56 records in 2021 and fell to 30 by 2024, a 46% decline over that three-year span, even before accounting for publication lag in the newest years.
- Reactor-core claims dominate the class mix. G21C (nuclear reactors) touches 64.6% of all records, while measurement (G01T) and plant-level systems (G21D) each sit at 16.5% — leaving control and data-processing classes comparatively open.
Filing growth compares 2021 (56 records) with 2024 (30) — 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 1,110 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
Nuclear safety and instrumentation patenting spans the hardware that watches a reactor core — neutron detectors, coolant-flow sensors, fuel-assembly monitoring — and the control logic that acts on what those sensors report. This dataset draws on 1,110 published records filed or published between 2015 and the August 2026 data cut-off, searched across titles, abstracts and claims for the intersection of nuclear safety or instrumentation language with specific hardware and control terms such as neutron detector, coolant flow, radiation dose, plasma control, safety control and fuel assembly.
Because a single filing can generate several continuations and be filed again in multiple jurisdictions, family-level counts give a fairer read of real inventive output than raw publication counts. The receiving-office spread here — concentrated in the United States, Europe and Japan, with meaningful volume from WIPO/PCT and China — reflects where reactor vendors and their supply chains actually seek protection, not where the underlying research happened.
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Filing trends and technology composition
Two views of the same 1,110-record corpus: how filing volume has moved year over year, and which IPC subclasses carry the claim density today.
Filing activity, 2017–2026
Annual filings ran at 51 in 2017, climbed to a peak of 56 in 2021, then eased to 30 by 2024 — a 46% pullback over that span. 2025 and 2026 show far fewer records, but that reflects the roughly 18-month lag between filing and publication rather than a real drop-off; treat the last one to two years as still filling in.
Technology composition by IPC subclass
G21C (nuclear reactors) appears on 64.6% of the 1,110 records, making it the dominant classification by a wide margin. G01T (radiation measurement) and G21D (nuclear power plants) each sit at 16.5%, with G06F (digital data processing), G01N (material analysis), G05B (control systems), A61N (radiation therapy) and G21F (radiation shielding) each under 6% — a signal that control-software and shielding claims are comparatively less crowded than core reactor hardware.
Shares are the percentage of the 1,110 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
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Try EurekaRepresentative filing and most-cited prior art
Reactor nuclear instrumentation system with fixed in-core neutron and gamma detector arrays
A reactor nuclear instrumentation system comprises a plurality of incore nuclear instrumentation assemblies arranged in a gap between a number of fuel assemblies charged in a reactor core, the incore nuclear instrumentation assemblies each including a fixed type neutron detector assembly comprising a plurality of fixed type neutron detectors dispersively arranged in a core axial direction and a fixed type gamma thermometer assembly comprising a plurality of fixed type gamma-ray heat detectors arranged at least in a same core axial direction as the fixed type neutron detectors; a power range detector signal processing device operatively connected to the fixed type neutron detector assemblies.Filed by Toshiba; published 2001-10-04. Reproduced from the patent abstract.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US4977529A | Training simulator for a nuclear power plant | 250 |
| 2 | US5813985A | Apparatus and methods for providing attenuation guidance and tumor targeting for external beam radiation ther… | 207 |
| 3 | US20060284094A1 | Detection of nuclear materials | 174 |
| 4 | US3832545A | Nuclear techniques for detecting the presence of explosives | 157 |
| 5 | US20110186720A1 | Device And Method For Particle Therapy Verification | 143 |
| 6 | US20070040115A1 | Method for calibrating particle beam energy | 141 |
| 7 | US4508677A | Modular nuclear reactor for a land-based power plant and method for the fabrication, installation and operati… | 129 |
| 8 | US6207953B1 | Apparatus and methods for determining gas saturation and porosity of a formation penetrated by a gas filled o… | 126 |
| 9 | US5078952A | Multi-sensor explosive detection system | 111 |
| 10 | US20020022781A1 | Products and methods for brachytherapy | 95 |
Citation counts reward older filings that have had more time to accumulate citations within this searched corpus — read them as a signal of influence on the field, not as a measure of current commercial importance.
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 filing strategy
Three patterns stand out once the record set is broken down by assignee, class and year.
A narrow leadership group, then a long tail
The five most active assignees hold 34.4% of all 1,110 records, and the ten most active hold 47.3%. That leaves more than half the corpus spread across a long tail of single- and few-filing entrants — a structure typical of a field with a handful of reactor vendors and national labs setting the pace, and many smaller players filing narrowly around specific components.
Volume has eased from its 2021 peak
Filing activity rose through the late 2010s, peaked at 56 records in 2021, and had fallen to 30 by 2024 — a 46% decline over that three-year window. Because publication lags filing by roughly 18 months, the very newest years in the trend chart will fill in further; the 2021-to-2024 comparison is the most reliable read available now.
Reactor-core claims crowd out adjacent classes
Nearly two-thirds of records carry a G21C classification, reflecting heavy claim activity around core hardware and fuel-assembly instrumentation. Control and regulating systems (G05B) and digital data processing (G06F) each sit under 6% of records, suggesting the software and control-logic layer sitting on top of that hardware is comparatively less staked out.
A small number of tight filing partnerships
Only ten co-assignee pairs appear in the dataset, and one pairing — a reactor developer and its innovation-arm partner — accounts for the strongest link at 30 shared records, well ahead of the next pairings. Most assignees in this field file independently rather than through joint ventures.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to nuclear safety & instrumentation patent landscape, with the prior art for and against each one.
| Assignee | Co-assignee | Shared families |
|---|---|---|
| NuScale Power LLC | Rock Creek Innovations LLC | 30 |
| Toshiba Corporation | Japan Nuclear Fuel Co Ltd | 12 |
| NuScale Power LLC | PARAGON ENERGY SOLUTIONS LLC | 8 |
| Hitachi Ltd | Hitachi Engineering Co Ltd | 5 |
| Toshiba Corporation | Toshiba Energy Systems & Solutions Corporation | 2 |
| Lawrence Livermore National Security LLC | STORM ERIK P | 2 |
| Lawrence Livermore National Security LLC | MOSES EDWARD I | 2 |
| Lawrence Livermore National Security LLC | LATKOWSKI JEFFERY F | 2 |
The dominant co-assignee link pairs a small modular reactor developer with its innovation-arm affiliate; a second pairing links a legacy reactor OEM with its national nuclear-fuel affiliate.
Who is filing, and where the gaps sit
Leadership in this field splits between legacy reactor OEMs with decades of instrumentation patents and newer small-modular-reactor entrants filing in tight, closely linked clusters.
One vendor sets the pace by a wide margin
The leading assignee holds 157 records, well ahead of the fifth-ranked filer at 36 and the tenth-ranked filer at 27. That gap suggests a long institutional history of in-core instrumentation and safety-system filing rather than a recent surge.
Even active filers have gone quiet in the newest year
Assignees that filed steadily through the mid-2020s show close to zero records in the latest tracked year, including one legacy filer down 100% year-over-year. This is consistent with publication lag rather than an actual stop in R&D, but it means recent-year rankings should be read cautiously.
SMR developers file through tight affiliate pairs
The strongest co-assignee link in the dataset pairs a small modular reactor developer with an affiliated innovation entity across 30 shared records — far more coordinated than the field's second-strongest pairing. This points to in-house safety-system IP being built jointly rather than licensed in.
Filing is US-centred with strong EPO and Japan volume
The United States receives the largest share of filings at 355, followed by Europe (EPO) at 159 and Japan at 139. WIPO/PCT filings at 93 and China at 69 suggest international-phase strategy and a growing but still secondary Chinese filing presence.
| Assignee | Recent year | YoY |
|---|---|---|
| NuScale Power LLC | 1 | — |
| Westinghouse Electric Corp | 0 | -100% |
| Toshiba Corporation | 0 | — |
| Mitsubishi Electric Corp | 0 | — |
| Rock Creek Innovations LLC | 0 | — |
| Mitsubishi Heavy Industries Ltd | 0 | — |
| Hitachi Ltd | 0 | — |
| China Nuclear Power Engineering Co Ltd | 0 | — |
Turning this landscape into a filing decision
The figures above describe where claim space is dense and where it is thin. Deciding whether to file, license or design around still requires a closer read of specific claims.
Run a freedom-to-operate check before drafting
Reactor-core instrumentation (G21C) is dense enough that a new filing risks overlapping existing claims from the leading assignees without a novelty search first.
Explore Patsnap Eureka →Track the SMR affiliate filing pattern
The strongest co-assignee pairing in this dataset signals how small modular reactor developers are building safety-system IP jointly; watching that pair's future filings flags where the category is heading.
Explore Patsnap Eureka →Revisit control-logic white space
Software and control-regulating classes carry far fewer records than core hardware classes, which may leave room for claims on the digital layer sitting above existing detector and coolant-flow hardware.
Explore Patsnap Eureka →Common questions about nuclear safety and instrumentation patents
One assignee leads the ranked list with 157 records, well ahead of the fifth-ranked filer at 36 and the tenth at 27. Together the five most active filers hold 34.4% of all 1,110 records in scope, and the ten most active hold 47.3%, which means the remaining half of the field is spread across a long tail of smaller filers. This concentration pattern is typical of a sector with a small number of established reactor vendors and national labs alongside many narrower component filers.
Filing activity rose through the late 2010s, peaked at 56 records in 2021, and had eased to 30 records by 2024 — a 46% decline over that three-year window. Publication lags filing by roughly 18 months, so 2025 and 2026 figures are still incomplete and should not be read as an ongoing collapse. The 2021-to-2024 comparison is the most reliable trend signal available in this dataset right now.
Nuclear reactor hardware, classified under IPC subclass G21C, appears on 64.6% of the 1,110 records in scope, making it by far the most heavily claimed area. Radiation measurement (G01T) and nuclear power plant systems (G21D) each touch 16.5% of records, while control-and-regulating systems and digital data processing each sit under 6%. Because a single record can carry multiple IPC codes, these shares add up to more than 100%, and the gap between hardware and control-software classes suggests where claim space is comparatively less crowded.
US20010026603A1, filed by Toshiba, describes a reactor nuclear instrumentation system built around fixed in-core neutron detector assemblies paired with fixed gamma-thermometer assemblies arranged along the same core axial direction, feeding a power-range detector signal processing device. It matters because it sits squarely in the densest classification in this dataset, G21C, and represents an early, detailed approach to combining neutron and gamma-heat detection in a single in-core instrumentation layout. Anyone designing a new in-core monitoring array should check claim scope here before finalizing a detector arrangement.
The clearest under-claimed areas sit at the intersection of established hardware classes and digital control: software-defined safety control logic, autonomous coolant-flow anomaly detection, and machine-learning-based fuel-assembly diagnostics all show thinner filing density than core reactor-hardware classes like G21C. These are leads for further freedom-to-operate research rather than confirmed open space, since a thin IPC count can also mean claims are captured under a different classification. Combining a specific sensing modality with a novel control algorithm is a reasonable starting point for drafting in these areas.
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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.