plutonium

noun

plu·​to·​ni·​um plü-ˈtō-nē-əm 

: a radioactive metallic element similar chemically to uranium that is formed as the isotope 239 by decay of neptunium and found in minute quantities in pitchblende, that undergoes slow disintegration with the emission of an alpha particle to form uranium 235, and that is fissionable with slow neutrons to yield atomic energy see Chemical Elements Table

Examples of plutonium in a Sentence

Recent Examples on the Web

However, these RTGs produce less and less power each year as the plutonium on board decays. —Thomas G. Moukawsher, Newsweek, 29 Nov. 2024

Rocky Flats, which housed facilities to produce nuclear weapons components from 1952 through the early 1990s, was contaminated by plutonium and other nuclear materials. —Gary Stoller, Forbes, 25 Oct. 2024

For instance, in partnership with the U.S. Energy Department, the lab looks at how robots can detect radiation at plutonium facilities at Los Alamos National Laboratory. —Lily Kepner, Austin American-Statesman, 18 Mar. 2024

North Korea conducted only one missile test and reprocessed no plutonium. —Frank Aum, Foreign Affairs, 22 Dec. 2022

Word History

Etymology

New Latin, from Pluton-, Pluto, the planet Pluto

First Known Use

1942, in the meaning defined above

Kids Definition

plutonium

noun

plu·​to·​ni·​um plü-ˈtō-nē-əm 

: a radioactive metallic element that is formed by decay of neptunium and found in minute quantities in pitchblende and that produces atomic energy by fission see element

Medical Definition

plutonium

noun

plu·​to·​ni·​um plü-ˈtō-nē-əm 

: a radioactive metallic element similar chemically to uranium that is formed as the isotope 239 by decay of neptunium and found in minute quantities in pitchblende, that undergoes slow disintegration with the emission of an alpha particle to form uranium 235, and that is fissionable with slow neutrons to yield atomic energy

—symbol Pu see Chemical Elements Table