Antimatter reactor

An antimatter reactor, antimatter pile, or main reactor was a power generation device that utilized antimatter. Antimatter reactors typically emitted neutrinos as a byproduct.

In 2151, Sub-Commander T'Pol detected neutrino emissions from a city on the Akaali homeworld despite the society being pre-industrial. The neutrinos were later found to be caused by a Malurian antimatter reactor, which was powering a secret underground veridium mining operation, eight meters beneath the surface. (ENT: "Civilization")

The prop in Voyager

The prop used as Malurian antimatter reactor was previously used as the main computer processor of the USS Voyager seen beamed aboard in the Star Trek: Voyager fourth season episode "Concerning Flight" though slightly re-dressed.

In September 2152, Commander Tucker noted that they had to shut down the main reactor to prevent being broiled inside the catwalk. (ENT: "The Catwalk")