PlainPatent

CPC technology class · G21

G21B - Fusion Reactors

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

372
US patents granted
#6/8
in G21
4.1%
G21 class share
+18%
5-yr velocity

The verdict

According to USPTO PatentsView, Fusion Reactors ranks #567 of 670 CPC technology areas - 372 US patents granted since 2015, with recorded grant volume up 18% over five years.

#567
of 670 CPC technology areas
372
US patents granted, 2015–2025
Tokamak Energy
leading assignee (30)
+18%
grant velocity, last 5 yrs

How G21B's grant cadence moved

Between 2020–2024, G21B recorded 172 grants versus 146 in 2015–2019 (+18% equal-window velocity). Across complete years, output peaked in 2020 at 43 grants and bottomed in 2015 at 16 (+169% peak-over-trough). Lead assignee Tokamak Energy Ltd holds 8.1% of the class ; the top three share 20.7%.

Leaderboard read

G21B concentration, lead at 8.1%

Tokamak Energy Ltd leads this historical grant record at 8.1% of G21B - us corporation assignees hold 54% of class grants (90 of 166). Figures describe granted US utility patents in this CPC subclass, not current investment or legal strength.

Leader's share
8.1%

30 of 372 grants

Top three share
20.7%

of the class's recorded grants

Lead over #2
1

more grants than TAE Technologies, Inc.

Where G21B sits inside G21

Among 8 subclasses in G21 (Nuclear PHYSICS; Nuclear Engineering), G21B ranks #6 and holds 4.1% of the parent class's 8,981 recorded grants. Sibling chips below are the other subclasses in the same parent class, not the nationwide volume/lead-share peers further down.

G21K 3,019 G21C 2,434 G21F 1,599 G21D 744 G21G 629 G21H 179 G21J 5

Rising assignees active in G21B

Company-wide grant multiples (2022–2024 vs 2019–2021) among assignees with ≥5 patents in this subclass. Growth is company-wide; class patent counts are subclass-specific.

  1. #1 Zap Energy, Inc. 4.00x 0 → 4 company-wide · 6 in G21B
  2. #2 Hefei Institutes of Physical Sciences, Chinese Academy of Sciences 2.80x 10 → 28 company-wide · 8 in G21B
  3. #3 Advanced Fusion Systems LLC 2.67x 3 → 8 company-wide · 5 in G21B
  4. #4 TAE Technologies, Inc. 1.88x 25 → 47 company-wide · 29 in G21B
  5. #5 Brilliant Light Power, Inc. 1.67x 3 → 5 company-wide · 8 in G21B

G21B grants by year, peak 2020 (43)

US utility-patent grants per year in G21B, 2015–2025 - recent five years are up 18% 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

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). 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…Brilliant Light PowerAlpha Ring Internation…Zap EnergyAdvanced Fusion…ShineState Atomic Energy…RadomFractal Antenna…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).

Questions about G21B

Which company holds the most patents in G21B?
Tokamak Energy Ltd leads G21B with 30 patents (8.1% of the subclass). By PatentsView assignee type, us corporations account for 54% of class grants.
Which G21B assignees grew fastest recently?
Among assignees with ≥5 grants in G21B, Zap Energy, Inc. shows the highest company-wide grant multiple (4.00x: 0 grants in 2019–2021 → 4 in 2022–2024) while holding 6 patents in this subclass. Growth is company-wide, not class-only.
How does G21B compare inside parent class G21?
Inside G21 (Nuclear PHYSICS; Nuclear Engineering), G21B ranks #6 of 8 subclasses by grant volume and holds 4.1% of the parent class total. The largest sibling is G21K (3,019 grants).

What to do with this data

G21B in context - here's where to go next.

Figures reflect USPTO PatentsView grant data through 2026-05-15; pending applications not yet granted are not counted.

Methodology - G21B figures are USPTO PatentsView granted-utility totals for this subclass (372 grants in the tracked window).

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.