control rod

noun

plural control rods
: a rod of a neutron-absorbing material (such as boron carbide) used to regulate the rate of nuclear fission in a reactor

Examples of control rod in a Sentence

Recent Examples on the Web In the reactors used at Fukushima, the control rods thrust up into the pressure vessel from below, and the housings around each control rod’s entry point were essentially weak spots. IEEE Spectrum, 31 Oct. 2011 Within 5 seconds, control rods thrust upward into the three operational reactors and stopped the fission reactions. IEEE Spectrum, 31 Oct. 2011 Desperate Measures To restart one or more reactors, Rosatom must lift the reactors’ control rods and dilute the boronic acid in the plant’s primary cooling water. IEEE Spectrum, 7 July 2023 Within seconds, control rods positioned above reactors at Ukraine’s three working plants dropped into cores to absorb neutrons and stop the chain reaction that could lead to a meltdown. Marc Santora, New York Times, 11 Apr. 2023 In the case of an accident in any reactor, control rods crafted from neutron-absorbing materials like cadmium plummet into the core and halt a runaway chain reaction that could otherwise lead to a core meltdown. Michael Koziol, IEEE Spectrum, 1 June 2018

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'control rod.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1906, in the meaning defined above

Time Traveler
The first known use of control rod was in 1906

Dictionary Entries Near control rod

Cite this Entry

“Control rod.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/control%20rod. Accessed 17 Jul. 2024.

Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!