G21J NUCLEAR EXPLOSIVES; APPLICATIONS THEREOF
Introduced: September 1968
Classification Context
- Section:
- PHYSICS
- Class:
- NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- Subclass:
- NUCLEAR EXPLOSIVES; APPLICATIONS THEREOF
Description
G21J covers nuclear explosive devices and their practical applications. This includes designs for nuclear weapons, thermonuclear devices, and related triggering or detonation mechanisms. The classification also encompasses peaceful applications of nuclear explosions, such as industrial excavation, seismic research, or mineral extraction where controlled nuclear detonation is employed. Related classified research on nuclear weapon design itself typically falls within national security restrictions rather than patent literature.
Additional Content
Uncontrollable reaction uncontrollable reactions Any fission or fusion reaction where event initiators (e.g. neutrons in the fission process) are produced in a number greater than required to sustain a chain reaction and where there is no mechanism to selectively moderate the reaction, e.g. a fission reactor where the operator has simply opted not to moderate or has failed to moderate the reaction is not a nuclear explosive device in the context of this subclass.
3 direct subcodes
Child Classifications
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Top Applicants
Top 10 applicants by patent filingsfor class G21, 2013–2023, worldwide · Source: EPO PATSTAT
- CHINA GENERAL NUCLEAR POWER CORPORATION 2,364
- CGN POWER COMPANY 1,899
- CHINA NUCLEAR POWER ENGINEERING COMPANY 1,870
- NUCLEAR POWER INSTITUTE OF CHINA 1,517
- KOREA ATOMIC ENERGY RESEARCH INSTITUTE KR 1,367
- WESTINGHOUSE ELECTRIC CORPORATION US 1,295
- KOREA HYDRO & NUCLEAR POWER COMPANY KR 1,196
- CHINESE ACADEMY OF SCIENCES 1,044
- CHINA INSTITUTE OF ATOMIC ENERGY 1,011
- HITACHI-GE NUCLEAR ENERGY 955