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CPC technology class · G21

G21B - Fusion Reactors

Fusion reactors. 372 US utility patents granted 2015–2025, with the leading assignees and year-by-year filing trajectory.

372
US patents granted
G21
Parent CPC class
20
Active assignees
+40%
5-yr velocity

The verdict

Fusion Reactors ranks #567 of 670 CPC technology areas - 372 US patents granted since 2015, with filing up 40% over five years.

#567
of 670 CPC technology areas
372
US patents granted, 2015–2025
Tokamak Energy
leading assignee (30)
+40%
filing velocity, last 5 yrs
Top assignee: Tokamak Energy Ltd (30 patents)

CPC subclass G21B - FUSION REACTORS - covers 372 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 G21B is shaped by 20 distinct companies actively filing in this space. Tokamak Energy Ltd leads with 30 patents, followed by TAE Technologies, Inc. at 29 grants and General Fusion Inc. at 18.

Filing activity in G21B is up 40% over the past five years versus 2015-2019, a sharp acceleration suggesting an emerging or fast-moving technology area. All counts come directly from USPTO PatentsView and reflect US granted utility patents only.

Is G21B innovation accelerating?

US utility-patent grants per year in G21B, 2015–2025 - recent five years are up 40% versus 2015–2019.

1020304050 20152016201720182019202020212022202320242025 33

Who leads G21B?

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

patents

What this shows Tokamak Energy is the most active filer in G21B, holding 30 of the 372 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 G21B
Rank Company Patents in G21B
#1 Tokamak Energy Ltd 30
#2 TAE Technologies, Inc. 29
#3 General Fusion Inc. 18
#4 Innoven Energy, Llc 11
#5 Hefei Institutes Of Physical Sciences, Chinese Academy Of Sciences 8
#6 Brilliant Light Power, Inc. 8
#7 Alpha RING International Limited 8
#8 Zap Energy, Inc. 6
#9 Advanced Fusion Systems Llc 5
#10 Shine Technologies, Llc 4
#11 State Atomic Energy Corporation “rosatom” Acts On Behalf Of The Russian Federation 4
#12 Radom Corporation 4
#13 Fractal Antenna Systems, Inc. 3
#14 Starfire Industries Llc 3
#15 IH IP Holdings Limited 3
#16 Blue Laser Fusion, Inc. 3
#17 Princeton Satellite Systems, Inc. 3
#18 MSNW Llc 3
#19 Board OF Regents OF THE Nevada System OF Higher Education ON Behalf OF THE OF THE University OF Nevada, RENO 2
#20 Phoenix, Llc 2

About This Class

CPC subclass G21B belongs to class G21.

372 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 G21B 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 G21B assignees by class footprint. Bubble size = patents in G21B. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Top 14 G21B assignees by class footprint. Bubble size = patents in G21B. Source: USPTO PatentsView (claim depth is company-wide across all classes). Scatter plot of 14 data points (bubble-sized by third dimension). 0510152025 010203040 Patents in G21B Avg claims / patent (company-wide) Tokamak EnergyTaeGeneral FusionInnoven EnergyHefei Institutes of P…Brilliant Light PowerAlpha Ring Internatio…Zap EnergyAdvanced Fusion Syste…ShineState Atomic Energy “…RadomFractal Antenna Syste…Starfire Industries
Top 14 G21B assignees by class footprint. Bubble size = patents in G21B. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Frequently Asked Questions

What is CPC class G21B?
CPC subclass G21B covers FUSION REACTORS. It belongs to CPC class G21 (NUCLEAR PHYSICS; NUCLEAR ENGINEERING), with 372 US utility patents granted since 2015.
How many patents have been filed in G21B?
372 US utility patents were granted in CPC subclass G21B between 2015 and 2025, based on USPTO PatentsView data.
Which company holds the most patents in G21B?
Tokamak Energy Ltd leads G21B with 30 patents, making it the most active assignee in this technology area.
How is patent data for G21B 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 G21B 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.