reactor

American  

[ree-ak-ter] / riˈæk tər /

noun

• reactors
  plural

1. a person or thing that reacts or undergoes reaction.

2. Electricity. a device whose primary purpose is to introduce reactance into a circuit.

3. Immunology, Veterinary Medicine. a patient or animal that reacts positively towards a foreign material.

4. Physics. nuclear reactor.

5. Chemistry. (especially in industry) a large container, as a vat, for processes in which the substances involved undergo a chemical reaction.

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reactor British  

/ rɪˈæktə /

noun

1. chem a substance, such as a reagent, that undergoes a reaction

2. short for nuclear reactor

3. a vessel, esp one in industrial use, in which a chemical reaction takes place

4. a coil of low resistance and high inductance that introduces reactance into a circuit

5. med a person sensitive to a particular drug or agent

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Other Word Forms

Derived Forms

• nonreactor
  noun

Inflected Forms

Nouns

• reactors
  plural

Etymology

Origin of reactor

First recorded in 1885–90; 1940–45 reactor for def. 4; react + -or ²

Explanation

A reactor is where a nuclear reaction is controlled, making it possible to create energy or any number of artificial elements. Reactor these days almost always refers to a nuclear reactor, where atomic fission of uranium or plutonium creates the heat used to make steam to generate electricity. Originally, though, reactor meant a vessel in which chemical processes were made to generate useful products such as nylon and artificial sweetener. These reactors are still used in chemical manufacturing plants.

Example Sentences

See Examples For:

reactor reactors

Constellation’s stock is rising sharply following a deal that equates to as much power as would be supplied by a new nuclear reactor.

From The Wall Street Journal ● Oct. 6, 2026

The companies said the supply covered by this agreement is equivalent to what would be produced by a new nuclear reactor.

From MarketWatch ● Oct. 6, 2026

Microsoft agreed to a 20-year power deal to support Constellation’s restart of the undamaged reactor at Pennsylvania’s Three Mile Island, the site of America’s worst nuclear accident.

From The Wall Street Journal ● Sep. 30, 2026

During the 1960s, its Molten Salt Reactor Experiment demonstrated that mixtures of molten salts could function as both nuclear fuel and reactor coolant.

From Science Daily ● Sep. 21, 2026

A maintenance worker was in the reactor building at unit 2 when he heard rumbling in the basement.

From "Meltdown" by Deirdre Langeland

The upgrades to 11 existing reactors will provide additional power to the grid that is roughly equivalent to building a new large reactor.

From The Wall Street Journal ● Oct. 6, 2026

Instead, the tech giant will help expand power generation at the plant and explore the possibility of adding new reactors there.

From The Wall Street Journal ● Sep. 30, 2026

The U.S. and South Korea reached a $200 billion deal to build an Alaska natural gas pipeline and eight large-scale nuclear reactors.

From Barron's ● Sep. 30, 2026

Its landmark cooling towers came down a few years later and defuelling of the nuclear reactors was completed in 2013.

From BBC ● Sep. 30, 2026

Most reactors were built long before fast, compact computers were available, and Fukushima Daiichi, which was commissioned in the 1970s, was no exception.

From "Meltdown" by Deirdre Langeland