neptunium

noun

nep·​tu·​ni·​um nep-ˈtü-nē-əm 

-ˈtyü-

: a radioactive metallic element that is chemically similar to uranium and is obtained in nuclear reactors especially as a by-product in the production of plutonium see Chemical Elements Table

Examples of neptunium in a Sentence

Recent Examples on the Web

These decays also contaminate the pit with helium, americium, uranium and neptunium, among other things. —Sarah Scoles, Scientific American, 14 Nov. 2023

Other researchers have found that green rust, a highly reactive variety of rust, immobilizes radioactive neptunium. —Patrick Morgan, Discover Magazine, 5 Apr. 2011

The technique requires bombarding uranium with a neutron to convert it to an unstable form of the element, which decays into neptunium and then fissile plutonium. —Andrew Moseman, Discover Magazine, 25 Mar. 2010

The amount of neptunium found in the air monitor at the school was a thousand times below the regulatory action level, said Mr. Edwards of the DOE. —Kris Maher, WSJ, 28 Apr. 2021

Sometime in 2017, the radioactive element neptunium 237 was also detected near the school. —The Cincinnati Enquirer, Cincinnati.com, 26 July 2019

Word History

Etymology

New Latin, from International Scientific Vocabulary Neptune

First Known Use

1941, in the meaning defined above

Kids Definition

neptunium

noun

nep·​tu·​ni·​um nep-ˈt(y)ü-nē-əm 

: a radioactive metallic element similar to uranium and obtained in nuclear reactors in the production of plutonium see element

Medical Definition

neptunium

noun

nep·​tu·​ni·​um nep-ˈt(y)ü-nē-əm 

: a radioactive metallic element that is chemically similar to uranium and is obtained in nuclear reactors as a by-product in the production of plutonium

—symbol Np see Chemical Elements Table