PlainPatent

CPC technology class · G21

G21D - Nuclear Power Plant

Nuclear power plant. 744 US utility patents granted 2015–2025, with the leading assignees and year-by-year filing trajectory.

744
US patents granted
G21
Parent CPC class
20
Active assignees
+7%
5-yr velocity

The verdict

Nuclear Power Plant ranks #493 of 670 CPC technology areas - 744 US patents granted since 2015, with filing up 7% over five years.

#493
of 670 CPC technology areas
744
US patents granted, 2015–2025
Mitsubishi Electric
leading assignee (55)
+7%
filing velocity, last 5 yrs
Top assignee: Mitsubishi Electric Corporation (55 patents)

CPC subclass G21D - NUCLEAR POWER PLANT - covers 744 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 G21D is shaped by 20 distinct companies actively filing in this space. Mitsubishi Electric Corporation leads with 55 patents, followed by Terrapower, Llc at 43 grants and Ge-hitachi Nuclear Energy Americas Llc at 40.

Filing activity in G21D is up 7% 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 G21D innovation accelerating?

US utility-patent grants per year in G21D, 2015–2025 - recent five years are up 7% versus 2015–2019.

405060708090 20152016201720182019202020212022202320242025 46

Who leads G21D?

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

patents

What this shows Mitsubishi Electric is the most active filer in G21D, holding 55 of the 744 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 G21D
Rank Company Patents in G21D
#1 Westinghouse Electric Company Llc 45
#2 Terrapower, Llc 43
#3 Ge-hitachi Nuclear Energy Americas Llc 40
#4 Nuscale Power, Llc 29
#5 Korea Atomic Energy Research Institute 27
#6 Korea Hydro & Nuclear Power Co., Ltd. 26
#7 Framatome 19
#8 BWXT Mpower, Inc. 17
#9 SMR Inventec, Llc 17
#10 BWXT Advanced Technologies Llc 13
#11 Doosan Heavy Industries & Construction Co., Ltd. 10
#12 Hitachi-ge Nuclear Energy, Ltd. 10
#13 Areva NP 10
#14 Areva Gmbh 10
#15 BWXT Nuclear Energy, Inc. 10
#16 DCNS 8
#17 Nugen, Llc 8
#18 Liqid Inc. 7
#19 Kepco Engineering & Construction Company Inc. 7
#20 Atomic Energy OF Canada Limited 7

About This Class

CPC subclass G21D belongs to class G21.

744 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 G21D 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 G21D assignees by class footprint. Bubble size = patents in G21D. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Top 14 G21D assignees by class footprint. Bubble size = patents in G21D. Source: USPTO PatentsView (claim depth is company-wide across all classes). Scatter plot of 14 data points (bubble-sized by third dimension). 510152025 01020304050 Patents in G21D Avg claims / patent (company-wide) Westinghouse ElectricTerrapowerGe-hitachi Nuclear En…Nuscale PowerKorea Atomic Energy R…Korea Hydro & Nuclear…FramatomeBwxt mpowerSmr InventecBwxt AdvancedDoosan Heavy Industri…Hitachi-ge Nuclear En…Areva NpAreva
Top 14 G21D assignees by class footprint. Bubble size = patents in G21D. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Frequently Asked Questions

What is CPC class G21D?
CPC subclass G21D covers NUCLEAR POWER PLANT. It belongs to CPC class G21 (NUCLEAR PHYSICS; NUCLEAR ENGINEERING), with 744 US utility patents granted since 2015.
How many patents have been filed in G21D?
744 US utility patents were granted in CPC subclass G21D between 2015 and 2025, based on USPTO PatentsView data.
Which company holds the most patents in G21D?
Mitsubishi Electric Corporation leads G21D with 55 patents, making it the most active assignee in this technology area.
How is patent data for G21D 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 G21D 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.