plutonium

noun
plu·​to·​ni·​um | \ plü-ˈtō-nē-əm How to pronounce plutonium (audio) \

Definition of plutonium

: 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 The first came in 1942, when Enrico Fermi was having trouble keeping his plutonium chain reaction running at a government research complex. Time, "1945: Chien-Shiung Wu," 5 Mar. 2020 Hanford made plutonium for nuclear weapons during the Cold War. oregonlive, "Hanford nuclear site’s inspection shortcomings revealed in watchdog report; parts of vast facility not entered in 50 years," 25 Feb. 2020 In contrast, the implosion bomb started with a ball of plutonium surrounded by a large sphere of conventional explosives. New York Times, "Fourth Spy at Los Alamos Knew A-Bomb’s Inner Secrets," 27 Jan. 2020 Bomb radiocarbon did not pose a significant threat to human health—certainly not compared with other elements released by bombs, such as plutonium and uranium. Carl Zimmer, The Atlantic, "Nuclear Tests Marked Life on Earth With a Radioactive Spike," 20 Mar. 2020 The Trump administration has also shown support for another alternative, known as reprocessing, that involves separating plutonium and uranium from spent fuel to make new fuel that can be used again. Josh Siegel, Washington Examiner, "Daily on Energy: Trump administration gives a little in acknowledging climate change," 24 Feb. 2020 Heavy water helps cool reactors and produces plutonium as a byproduct that can potentially be used in nuclear weapons. Fox News, "Iran starts new development on heavy water nuclear reactor, official says," 24 Dec. 2019 This new warhead will require its own new kind of weapons-grade plutonium core. Caroline Delbert, Popular Mechanics, "Experts Call for Firm Age Limit on Plutonium Weapons," 28 Jan. 2020 In 1942, the federal government chose the Hanford Reach for its first plutonium production facility, where the fuel for Fat Man and the majority of the next 60,000 atomic bombs would be refined. Patrick Symmes, Harper's magazine, "The $68,000 Fish," 28 Oct. 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'plutonium.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of plutonium

1942, in the meaning defined above

History and Etymology for plutonium

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

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The first known use of plutonium was in 1942

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Last Updated

26 May 2020

Cite this Entry

“Plutonium.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/plutonium. Accessed 29 May. 2020.

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More Definitions for plutonium

plutonium

noun
How to pronounce plutonium (audio)

English Language Learners Definition of plutonium

: a radioactive element that is used to make nuclear energy and nuclear weapons

plutonium

noun
plu·​to·​ni·​um | \ plü-ˈtō-nē-əm How to pronounce plutonium (audio) \

Kids Definition of plutonium

: a radioactive metallic chemical element formed from neptunium and used for releasing atomic energy

plutonium

noun
plu·​to·​ni·​um | \ plü-ˈtō-nē-əm How to pronounce plutonium (audio) \

Medical Definition of plutonium

: 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

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More from Merriam-Webster on plutonium

Rhyming Dictionary: Words that rhyme with plutonium

Spanish Central: Translation of plutonium

Nglish: Translation of plutonium for Spanish Speakers

Britannica.com: Encyclopedia article about plutonium

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