Reactor Coolant Pump Patents: Top Companies & Trends 2026
A data-driven look at reactor coolant pump patents: who leads filings, how the technology splits across IPC classes, filing trends since 2017, and where white space remains for new entrants.
Filing growth = 2021 (13 records) → 2024 (15); 2024 is the last year we treat as complete. Top-5 share = the 5 largest assignees ÷ all 1,119 records in scope (CR5), not the ranked leaders only.
What the reactor coolant pump patent record shows
Reactor coolant pump technology sits at the intersection of nuclear reactor design and rotating machinery engineering, which is why the dataset spans G21C nuclear reactor classes alongside F04D pump classifications and F16J seal and gasket art. The 1,119 records in scope, filed since 2015 and pulled from receiving offices across Japan, the United States, South Korea, Europe, the United Kingdom and China, describe a field where a handful of reactor vendors and national nuclear utilities hold a disproportionate share of the claim space.
That concentration matters for anyone assessing freedom to operate: dense filing at the top does not mean the underlying engineering problem is solved, only that the claim space around known configurations is occupied. The more useful question is which sub-branches — seal design, passive injection, control integration — still have room for a distinct claim.
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Filing trends and technology composition
Two views of the same 1,119-record dataset: how filing activity has moved year over year, and how the technology splits across IPC subclasses. Both use the full record set as denominator, so class shares sum to more than 100% because a single record can carry several classifications.
Filing activity, 2017-2026
Annual filings peaked at 34 in 2018, fell back over the following years, then recovered from 13 in 2021 to 15 in 2024 — a 15% rise over that span. The 2025 and 2026 figures (down to 3 by 2026) reflect publication lag rather than a genuine slowdown; grant and publication typically trail filing by around 18 months.
Publication lags filing by roughly 18 months, so 2025 onwards are still filling in. Growth rates on this page therefore end at 2024; running them to the last bar would understate the field.
Technology composition by IPC subclass
G21C (nuclear reactors) dominates at 85.6% of the 1,119 records, with G21D (nuclear power plants) and F04D (non-positive-displacement pumps) as the next largest branches at 32.1% and 20.6%. Seals and gaskets (F16J), radiation shielding (G21F), motors (H02K), steam generation (F22B) and control systems (G05B) each cover a single-digit share, marking them as narrower, more specialised claim territory.
Shares are the percentage of the 1,119 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Reactor Coolant Pump Patent Landscape with Eureka
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Try EurekaRepresentative filing and most-cited prior art
Passive nitrogen injecting device for nuclear reactor coolant pump
The present invention relates to a passive nitrogen injecting device for a nuclear reactor coolant pump, the device comprising: a nitrogen supply unit for supplying nitrogen; a pressure control valve for controlling the supply of nitrogen from the nitrogen supply unit according to pressure; an accumulator for filling the nitrogen supplied through the pressure control valve at a set pressure, and supplying the filled nitrogen in the event that an accident involving coolant loss occurs; and an isolation valve for controlling the supply of the nitrogen from the accumulator into a seal housing of a nuclear reactor coolant pump.Filed by Korea Hydro & Nuclear Power, this record targets seal-housing behaviour during loss-of-coolant events using a passive, pressure-driven accumulator rather than an active injection system.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20100316181A1 | Integral helical coil pressurized water nuclear reactor | 186 |
| 2 | US4753771A | Passive safety system for a pressurized water nuclear reactor | 170 |
| 3 | US4508677A | Modular nuclear reactor for a land-based power plant and method for the fabrication, installation and operati… | 129 |
| 4 | US5223207A | Expert system for online surveillance of nuclear reactor coolant pumps | 127 |
| 5 | US4072563A | Industrial technique for an integral compact reactor | 107 |
| 6 | US4990054A | Device incorporating micro-porous membrane for venting gases from seal assembly of a reactor coolant pump | 85 |
| 7 | US3984282A | Passive containment system for a nuclear reactor | 77 |
| 8 | US5485491A | Online diagnostic system for rotating electrical apparatus | 74 |
| 9 | US4285770A | Jet pump with labyrinth seal | 73 |
| 10 | US3943719A | Hydride-dehydride power system and methods | 70 |
Citation counts reflect influence within the searched corpus and favour older filings; they are not a measure of current commercial importance.
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Filing concentration, class distribution and citation patterns each point to a different part of the same picture: an established core claimed early by a small group, and narrower branches where the record is thinner.
The core is claimed by a small group
The leading assignee holds 188 records on its own, more than triple the fifth-place figure of 51. That drop-off from first to fifth place is steep rather than gradual, which suggests the core mechanical and safety-system configurations are locked up by a small number of reactor vendors and national utilities rather than contested broadly.
Reactor-level claims dominate over component-level ones
Nuclear reactor classifications outweigh pump-specific (F04D, 20.6%) and control-system (G05B, 1.8%) classes by a wide margin. That imbalance suggests coolant pump innovation is still framed mostly at the reactor-system level, leaving instrumentation and control integration comparatively under-claimed relative to its safety relevance.
A modest recovery after the 2018 peak
Filings peaked at 34 in 2018, then settled into a lower band before rising from 13 in 2021 to 15 in 2024. That is real but measured growth, not a return to peak activity, and it comes years after the initial wave of integral and passive-safety reactor designs that dominate the most-cited records.
Citation leaders skew toward integral reactor design
The most-cited records describe integral and modular reactor architectures and passive safety systems rather than pump hardware itself, including one expert-system patent for online pump surveillance. That pattern reflects how citation counts favour older, foundational filings — useful for tracing lineage, less useful for judging what is competitively active today.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to reactor coolant pump patent landscape, with the prior art for and against each one.
Where to take this analysis
The dataset points to specific next steps depending on whether the goal is freedom-to-operate, white-space discovery, or monitoring a competitor's portfolio.
Map claim boundaries around the top assignees
With 42.0% of records held by five assignees, a freedom-to-operate review should start by mapping exactly what those portfolios claim versus what they merely disclose, particularly around seal housing and passive injection mechanisms.
Explore assignee portfolios in EurekaProbe the under-claimed control-system branch
G05B control and regulating classifications cover only 1.8% of records despite the safety relevance of pump monitoring, suggesting room for a distinct claim in instrumentation and control integration rather than mechanical redesign.
Run a white-space search in EurekaTrack filing recovery by jurisdiction
Receiving-office activity spans Japan, the United States, South Korea, Europe, the United Kingdom and China at different volumes; overlaying the 2021-2024 filing recovery by office shows where renewed investment is concentrated.
Compare jurisdictions in EurekaCommon questions about reactor coolant pump patents
The ranked leader in this dataset holds 188 of the 1,119 records in scope, well ahead of the fifth-ranked assignee at 51. The top 5 assignees combined account for 42.0% of all records, and the top 10 reach 55.8%, so the field is concentrated among a small group of reactor vendors and national nuclear utilities rather than spread evenly. That concentration is a useful starting point for a freedom-to-operate review, but it does not tell you which specific claims are enforceable against a new design — that requires reading the actual claim language.
Filing activity peaked at 34 records in 2018, then settled lower before recovering from 13 records in 2021 to 15 in 2024, a 15% increase over that span. The 2025 and 2026 figures appear much lower, but that reflects publication lag of roughly 18 months rather than an actual drop in filing activity — recent applications simply have not published yet. Based on the complete years available, the honest read is modest growth off a lower base, not a return to 2018 levels.
The dataset spans several IPC subclasses: G21C (nuclear reactors) covers 85.6% of the 1,119 records, G21D (nuclear power plants) covers 32.1%, and F04D (non-positive-displacement pumps) covers 20.6%. Narrower classes include F16J (seals and gaskets, 5.1%), G21F (radiation shielding, 3.3%), H02K (motors and generators, 2.5%), F22B (steam generation, 2.1%) and G05B (control systems, 1.8%). Because a single record can carry multiple classifications, these shares add up to more than 100%, and the low share for control systems relative to the safety role of pump monitoring is one of the more notable gaps.
US20170062082A1, filed by Korea Hydro & Nuclear Power, describes a passive nitrogen injecting device for a nuclear reactor coolant pump: a nitrogen supply unit, a pressure control valve, an accumulator that fills with nitrogen at a set pressure, and an isolation valve that releases that nitrogen into the pump's seal housing during a loss-of-coolant event. The mechanism is specifically passive, meaning it relies on stored pressure rather than an active control system to respond to an accident condition. Anyone designing a seal-protection system for a coolant pump should check whether their approach falls inside this specific accumulator-and-isolation-valve configuration or uses a genuinely different triggering mechanism.
The clearest signal is the IPC composition: G05B control and regulating systems cover only 1.8% of the 1,119 records, and H02K motor and generator classifications cover 2.5%, both far below the 85.6% share held by core reactor classifications. That gap suggests instrumentation, monitoring and control integration for coolant pumps are comparatively under-claimed relative to their role in reactor safety cases. A first claim in that space would likely combine a specific sensor or control architecture with a defined pump failure mode, rather than claiming a general monitoring concept.
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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.