Small Modular Reactor Patents: Top Companies & Filing Trends 2026
- Concentrated at the top. The five leading assignees hold 44.4% of all 1,390 records in scope, and the top ten hold 59.6% — a field where a handful of programmes have staked out most of the core reactor and coolant claims.
- Reactor-level claims dominate. 81.5% of records sit in G21C (nuclear reactors), while radiation protection, valves, heat exchange and steam generation each sit under 6% — narrow bands where a first-mover claim still carries weight.
- Filing kept climbing through the last complete year. From 2021 to 2024, filings rose from 84 to 91 — an 8% increase — even as the peak single year on record, 2020 at 100, has not yet been matched again.
Filing growth compares 2021 (84 records) with 2024 (91) — 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 1,390 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
This landscape covers 1,390 published records matching small modular reactor and modular nuclear reactor terminology combined with core subsystem language: reactor coolant, fuel assembly, radiation field, safety barrier, nuclear fuel and neutron flux. The scope spans filings from 2015 through the 2026 data cut-off, drawing on the same family-level counting used throughout the ranking so that continuation filings and multi-jurisdiction duplicates do not inflate any single programme’s footprint.
Because publication typically lags filing by around 18 months, the most recent one to two years in any trend understate real filing activity. Read the concentration and technology-mix figures as a picture of claimed ground as of the last complete filing year, not as a final tally of what is currently being filed.
Filing trend and technology composition
Two views of the same 1,390-record dataset: filing volume by year, and where those records sit across IPC subclasses. Both are read against the denominators stated below — subclass shares add to more than 100% because a single record can carry several IPC codes.
Filing trend, 2017-2026
Filings rose from 56 in 2017 to a peak of 100 in 2020, then continued at a high level: 84 in 2021 climbing to 91 in 2024, an 8% increase over that span. 2025 and 2026 show lower counts (10 by the 2026 cut-off), consistent with publication lag rather than a real drop in filing activity.
Technology composition by IPC subclass
G21C (nuclear reactors) covers 81.5% of the 1,390 records, with G21D (nuclear power plants) at 24.2%. Everything else — radiation protection (G21F, 5.0%), valves (F16K, 3.2%), heat exchange (F28D, 3.2%), steam and thermal power plants (F01K, 3.2%), steam generation (F22B, 2.4%) and gas-turbine plants (F02C, 1.9%) — sits in single digits, marking these as narrower, less-crowded claim areas relative to core reactor design.
Shares are the percentage of the 1,390 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Small Modular Reactors Patent Landscape with Eureka
This page is one run against one query. Ask Eureka your own question about small modular reactors patent landscape and every answer comes back with the patent numbers behind it.
Try EurekaMost-cited records and a representative recent filing
Small modular reactor including small fuel assemblies
Filed by Korea Hydro & Nuclear Power, this 2025 application describes a small modular reactor whose core is arranged in a first fuel-assembly zone surrounded by multiple separated second zones, with first- and second-size fuel assemblies distributed across them. The structure targets fine-grained control over core power distribution using differently sized assemblies rather than a uniform core layout.Abstract trimmed for length; full claim set available via the source record.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20150143806A1 | Quintuple-Effect Generation Multi-Cycle Hybrid Renewable Energy System with Integrated Energy Provisioning, S… | 268 |
| 2 | US4508677A | Modular nuclear reactor for a land-based power plant and method for the fabrication, installation and operati… | 129 |
| 3 | US20180347406A1 | Quintuple-effect generation multi-cycle hybrid renewable energy system with integrated energy provisioning, s… | 102 |
| 4 | US20210098143A1 | Offshore and marine vessel-based nuclear reactor configuration, deployment and operation | 80 |
| 5 | US20180075931A1 | Heat pipe molten salt fast reactor with stagnant liquid core | 79 |
| 6 | US20180226159A1 | Modular nuclear reactors, fuel structures, and related methods | 67 |
| 7 | US20130083879A1 | In-core instrument thimble assembly | 66 |
| 8 | EP2955372A2 | Quintuple-effect generation multi-cycle hybrid renewable energy system with integrated energy provisioning, s… | 64 |
| 9 | US20160217874A1 | Molten Salt Reactor | 62 |
| 10 | US20130336441A1 | Small modular reactor safety systems | 58 |
Citation counts favour older records simply because they have had more time to accumulate citations inside the searched corpus; treat this table as a signal of influence, not of current technical importance.
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Three findings that shape where a new filing is likely to run into dense prior art, and where it is not.
A small group holds most of the core claim space
The leading assignee alone accounts for 202 records, and the top five combined reach 617 records, 44.4% of all 1,390 in scope. The top ten extend that to 59.6%. New entrants working on core reactor vessel or primary-loop design should expect to design around this group's claims rather than file into open ground.
Reactor-level claims crowd out everything downstream
G21C absorbs the large majority of filings, but radiation protection, steam generation, valves and heat exchange each stay under 6% of records. These are the subsystems most likely to still have room for a defensible first claim, even inside an otherwise dense field.
Activity held steady through the last complete year
Filings grew from 84 in 2021 to 91 in 2024, an 8% rise, after peaking at 100 in 2020. The apparent decline from 2025 onward is a publication-lag artefact, not evidence that filing has slowed — treat the last one to two years as incomplete.
Joint filings are rare and concentrated in a few pairings
Only nine co-assignee pairings appear across the dataset, with the strongest pairs each reaching 10 shared records. Co-filing is not the norm in this field; most programmes patent independently rather than through joint ventures.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to small modular reactors patent landscape, with the prior art for and against each one.
Assignee landscape and recent momentum
The ranking covers 100 companies, counted by family. It is the full ranking the data endpoint returns, not a top-50 or top-100 cut, and the leader alone sits well ahead of the field.
One programme sits well ahead of the field
The leading assignee holds 202 records, more than double the fifth-place count of 69 and roughly seven times the tenth-place count of 28. That gap suggests a single sustained filing programme rather than a series of one-off applications.
A steep drop-off after the top five
Filing counts fall sharply between the top five and the rest of the ranked group, from 69 at fifth place to 28 at tenth. Below that, the long tail thins quickly, consistent with a field where a handful of national labs and reactor vendors dominate and most others file occasionally.
Recent-year counts are down across the leading names, but read the lag first
Several of the most active assignees show sharp year-on-year declines in the latest year, some to zero. Given the roughly 18-month publication lag, this reflects filings still working through publication rather than a genuine pullback from these programmes.
| Assignee | Recent year | YoY |
|---|---|---|
| NuScale Power LLC | 1 | -75% |
| TerraPower LLC | 1 | -67% |
| Westinghouse Electric Corp | 0 | -100% |
| Babcock & Wilcox mPower Inc | 0 | — |
| SMR InvenTech LLC | 0 | — |
| BWXT mPower Inc | 0 | -100% |
| Thorium Power Inc | 0 | — |
| Rolls-Royce SMR Ltd | 0 | -100% |
Where to take this analysis
The dataset points to specific next steps depending on whether the goal is freedom-to-operate, licensing, or identifying where to file next.
Map claims against the leading five assignees
With 44.4% of records held by five companies, a freedom-to-operate check against those portfolios specifically, rather than the full 100-company ranking, will surface the highest-risk overlaps fastest.
Explore assignee claims in EurekaTest the under-claimed subsystem branches
Radiation protection, valves, heat exchange and steam generation each sit under 6% of the 1,390 records. Drafting a first claim in one of these branches, anchored to the specific mechanism rather than the reactor as a whole, avoids the densest prior art.
Run a white-space search in EurekaRe-check 2025-2026 filings once they clear the lag
The 2025 and 2026 counts will keep rising as publication catches up; revisit the trend in six to twelve months before drawing conclusions about a slowdown.
Set a filing-trend alert in EurekaCommon questions about SMR patenting
The dataset's leading assignee holds 202 family-level records, well ahead of the fifth-ranked company at 69 and the tenth at 28. The top five assignees together account for 617 records, 44.4% of all 1,390 in scope, and the top ten reach 59.6%. This concentration means a small number of reactor vendors and national programmes have staked out most of the core design claims, so competitive tracking should focus on that group first.
The large majority of records, 81.5% of the 1,390 in scope, fall under IPC subclass G21C, nuclear reactors, with nuclear power plants (G21D) at 24.2%. Radiation protection, valves, heat exchange, steam generation and gas-turbine integration each sit under 6% of records. Because a single patent can carry multiple IPC codes, these shares add up to more than 100%, and they show that reactor-core design is far more crowded than the surrounding subsystems.
Filing rose from 56 records in 2017 to a peak of 100 in 2020, then held at a high level, going from 84 in 2021 to 91 in 2024, an 8% increase over that span. The lower counts shown for 2025 and 2026 reflect the roughly 18-month gap between filing and publication, not a genuine slowdown. Any read on the most recent one to two years should treat those totals as still filling in.
The clearest under-claimed ground sits outside core reactor design, in subsystems each holding under 6% of the 1,390 records: radiation shielding geometry, compact heat-exchanger loops, passive valve actuation, steam generator tube-bundle layout and gas-turbine integration for waste heat recovery. These branches are narrower than core reactor claims but far less crowded, making them more realistic targets for a defensible first claim than the primary reactor vessel or coolant loop, where the leading assignees already hold dense portfolios.
Independently, for the most part. Across the dataset there are only nine co-assignee pairings, with the strongest reaching 10 shared records each. That is a small fraction of the 1,390 total records, so joint ventures and co-development filings are the exception rather than the norm in this field, and most competitive activity should be tracked assignee by assignee rather than by looking for partnership signals.
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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.