uranium 238

American  

noun

Chemistry.

1. the radioactive uranium isotope having a mass number 238, comprising 99.28 percent of natural uranium: used chiefly in nuclear reactors as a source of the fissionable isotope plutonium 239.

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Etymology

Origin of uranium 238

First recorded in 1940–45

Example Sentences

See Examples For:

uranium 238

"The ratio of isotopes of uranium 238 to 225 on our planet is different than anywhere else in the universe because the two isotopes decay at different timescales," Brownless said.

From Salon ● Sep. 1, 2023

This combination of elements indicated that the explosion was the "fission-fusion-fission" type, which gets much of its energy from the fission of normally inactive uranium 238.

From Time Magazine Archive

The centrifuges take uranium-bearing ore or a mixture called yellowcake and separate out the 3% of uranium 235, which is fissionable, from the 97% of uranium 238, which is not.

From Time Magazine Archive

The elements were formed when neutrons from the explosion hit atoms of uranium 238 and were captured by its nucleus.

From Time Magazine Archive

About 95 percent of each pellet is uranium 238, an isotope with a half-life of 4.5 billion years.

From "Meltdown" by Deirdre Langeland