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CPC technology class · G21

G21C - Nuclear Reactors

Nuclear reactors. 2,434 US utility patents granted 2015–2025, with the leading assignees and year-by-year filing trajectory.

2,434
US patents granted
G21
Parent CPC class
20
Active assignees
+8%
5-yr velocity

The verdict

Nuclear Reactors ranks #349 of 670 CPC technology areas - 2,434 US patents granted since 2015, with filing up 8% over five years.

#349
of 670 CPC technology areas
2,434
US patents granted, 2015–2025
Westinghouse Electric
leading assignee (265)
+8%
filing velocity, last 5 yrs
Top assignee: Westinghouse Electric Company Llc (265 patents)

CPC subclass G21C - NUCLEAR REACTORS - covers 2,434 US utility patents granted between 2015 and 2025 according to USPTO PatentsView records, within the broader CPC class G21 (NUCLEAR PHYSICS; NUCLEAR ENGINEERING). See our CPC classification guide for how the system works.

The competitive landscape in G21C is shaped by 20 distinct companies actively filing in this space. Westinghouse Electric Company Llc leads with 265 patents, followed by Ge-hitachi Nuclear Energy Americas Llc at 173 grants and Terrapower, Llc at 117.

Filing activity in G21C is up 8% over the past five years versus 2015-2019, a relatively steady filing pace. All counts come directly from USPTO PatentsView and reflect US granted utility patents only.

Is G21C innovation accelerating?

US utility-patent grants per year in G21C, 2015–2025 - recent five years are up 8% versus 2015–2019.

100150200250300 20152016201720182019202020212022202320242025 114

Who leads G21C?

The 12 most active assignees in NUCLEAR REACTORS - wider bars mean more grants

patents

What this shows Westinghouse Electric is the most active filer in G21C, holding 265 of the 2,434 patents in this class. Concentration at the top signals how contestable this technology area is for new entrants.

Source USPTO PatentsView, granted utility patents As of 2015–2025 grant years
View data table
Top patent holders in CPC subclass G21C
Rank Company Patents in G21C
#1 Westinghouse Electric Company Llc 265
#2 Ge-hitachi Nuclear Energy Americas Llc 173
#3 Terrapower, Llc 117
#4 BWXT Mpower, Inc. 79
#5 Korea Atomic Energy Research Institute 78
#6 Framatome 71
#7 Nuscale Power, Llc 69
#8 Holtec International 58
#9 Kepco Nuclear FUEL Co., Ltd. 46
#10 Hitachi-ge Nuclear Energy, Ltd. 42
#11 Areva NP 42
#12 Areva Gmbh 32
#13 SMR Inventec, Llc 32
#14 Korea Hydro & Nuclear Power Co., Ltd. 30
#15 BWXT Advanced Technologies Llc 25
#16 Westinghouse Electric Sweden AB 25
#17 Global Nuclear Fuel-americas, Llc 24
#18 Atomic Energy OF Canada Limited 23
#19 Battelle Energy Alliance, Llc 22
#20 BWXT Nuclear Energy, Inc. 22

About This Class

CPC subclass G21C belongs to class G21.

2,434 patents were granted in this class between 2015 and 2025.

20 companies actively patent in this space.

Classification System

Cooperative Patent Classification (CPC) is a hierarchical patent classification system used by the USPTO and EPO.

← All Technology Classes Technology Rankings →

Footprint here vs. claim strategy

Each dot is a leading G21C assignee, placed by how many patents it holds in this class (horizontal) against its company-wide average claims per patent (vertical) - a read on whether the class is led by broad-but-shallow filers or focused deep-claim players.

Top 14 G21C assignees by class footprint. Bubble size = patents in G21C. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Top 14 G21C assignees by class footprint. Bubble size = patents in G21C. Source: USPTO PatentsView (claim depth is company-wide across all classes). Scatter plot of 14 data points (bubble-sized by third dimension). 0510152025 0100200300 Patents in G21C Avg claims / patent (company-wide) Westinghouse ElectricGe-hitachi Nuclear En…TerrapowerBwxt mpowerKorea Atomic Energy R…FramatomeNuscale PowerHoltec InternationalKepco Nuclear FuelHitachi-ge Nuclear En…Areva NpArevaSmr InventecKorea Hydro & Nuclear…
Top 14 G21C assignees by class footprint. Bubble size = patents in G21C. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Frequently Asked Questions

What is CPC class G21C?
CPC subclass G21C covers NUCLEAR REACTORS. It belongs to CPC class G21 (NUCLEAR PHYSICS; NUCLEAR ENGINEERING), with 2,434 US utility patents granted since 2015.
How many patents have been filed in G21C?
2,434 US utility patents were granted in CPC subclass G21C between 2015 and 2025, based on USPTO PatentsView data.
Which company holds the most patents in G21C?
Westinghouse Electric Company Llc leads G21C with 265 patents, making it the most active assignee in this technology area.
How is patent data for G21C collected?
Patent data comes from USPTO PatentsView, a public research dataset maintained by the United States Patent and Trademark Office. It covers all US granted utility patents and assigns CPC codes based on the technology described in each patent.
What is the difference between CPC class and subclass?
A CPC class (e.g., G21) is a broad technology category. Subclasses like G21C provide finer granularity within that category. PlainPatent organizes data at the subclass level (4-character codes) for the most useful view of technology domains.

Read our methodology - how this data is sourced, computed, and verified.

Data sourced from USPTO PatentsView - official U.S. government patent data. See our methodology for computation details. Retrieved and formatted by PlainPatent Editorial

Every figure on PlainPatent is rendered directly from USPTO source data, no number is typed in by an editor. This page draws directly on USPTO source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.