UNSC Reactor

From Halopedia, the Halo wiki

A render of the UNSC reactor.
Different views of the UNSC Reactor.

The reactor is a United Nations Space Command structure used to power a prefabricated Firebase unit.[1]


Design details[edit]

An ONI reactor manned by UNSC Marines on Arcadia.

Prefabricated firebases contain a fusion reactor powered by reactions between hydrogen isotopes. The reactor allows a UNSC Firebase to operate very sophisticated systems. These reactors are modular allowing for quick setup. In order to meet a firebase's power requirements, an additional power unit can be placed on the other socket present on the base of the structure, thus upgrading the structure to an Advanced Reactor.[1] These reactors are only employed on older "Pod" firebases, as more modern firebase designs are capable of only relying on generators to meet their power requirements.[2]


Several standalone reactors were employed by the Arcadia ONI facility. During the Battle for Arcadia, these reactors were co-opted by forces of the UNSC Spirit of Fire to siphon additional power.[3][4]

In 2558, a reactor was made the target of an attack by Covenant remnants. During the attack, the remnants were able to hijack an M510 Mammoth and set it on a collision course with the facility, though the vehicle was stopped by Blue Team before it could destroy the reactor.[5]

In-game information[edit]

Halo Wars[edit]

A screenshot of the default UNSC Reactor building.
The Reactor in-game in Halo Wars.

"UNSC Reactors provide the energy needed to access the advanced buildings, units and technology upgrades."
— In-game description

In Halo Wars, the first Reactor costs Resources 250 to be built; each subsequent Reactor costs an additional Resources 250 than the previous reactor. Reactors increase the Tech level Tech Level of the UNSC, which allows them to field heavier and more advanced units. For each unit, building and upgrade of the UNSC, a certain technology level is required to make use of it. Typically the most advanced of units/upgrades require more energy units than less advanced ones. Each reactor constantly provides at least Tech level 1, and will continue to do so until destroyed. With Resources 1,200, a default reactor can be upgraded to an advanced reactor, which provides an output of power equal to two default reactors, or Tech level 2.

Reactors have been replaced by Generators in Halo Wars 2 to accommodate an adjusted power gameplay mechanic.

Name Type Cost Description
Population Tech Resources
Advanced Reactor Upgrade N/A Tech level 0 Resources 1,200 This Reactor provides enough energy to match the output of two Reactors.


  • When even slightly damaged from enemy fire, reactors can be seen venting a blue substance.
  • Reactors can be found abandoned throughout the Halo Wars campaign and skirmish maps. Those in campaign are empty while those found in skirmish maps are guarded by hostile units.


List of appearances[edit]