subcritical

American  

[suhb-krit-i-kuhl] / sʌbˈkrɪt ɪ kəl /

adjective

1. Physics. pertaining to a state, value, or quantity that is less than critical, especially to a mass of radioactive material.

2. being of less than critical importance.

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subcritical British  

/ sʌbˈkrɪtɪkəl /

adjective

1. physics (of a nuclear reaction, power station, etc) having or involving a chain reaction that is not self-sustaining; not yet critical

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Etymology

Origin of subcritical

First recorded in 1940–45; sub- + critical

Example Sentences

The U.S. has been modernizing its warheads with subcritical testing that produces zero nuclear yield.

From The Wall Street Journal • Nov. 17, 2025

"Other tests, both subcritical, or those without a chain nuclear reaction, and carrier tests, have never been prohibited," Lavrov added.

From Barron's • Nov. 11, 2025

Washington, however, is preparing to conduct next year at the Nevada Test Site two so-called subcritical experiments involving fissile materials in amounts too small to ignite a nuclear explosion.

From Reuters • Oct. 10, 2023

It would also serve as a prototype for subcritical nuclear power reactors that, unlike existing plants, do not sustain a chain reaction in their core.

From Science Magazine • Dec. 6, 2022

They found the fissionables magazine, and in it plenty of plutonium, each subcritical slug in a five-hundred-pound collapsium canister.

From The Cosmic Computer by Piper, H. Beam