Feed The Beast Wiki
Feed The Beast Wiki
This page is about the fusion reactor added by Mekanism. For other uses, see Fusion Reactor.

The fusion reactor is a multiblock structure added by Mekanism. It is used for generating large amounts of power.


The exact list of materials varies depending on how many Reactor Glass and Reactor Port are used, as these blocks replace Reactor Frame:


Layer 1

Layer 1 is a star made out of Reactor Frame, 5 blocks across. The 5 blocks in the middle may be replaced with ports.

Layer 2

Layer 2 is a hollow 5x5 square with the corners removed. The middle blocks of each side may be replaced with ports or glass.

Layer 3

Layer 3 is also a hollow 5*5 square, but with the corners. The 3 blocks in the middle of each side may be ports or glass.

Layers 4 and 5

Layer 4 is the same as layer 2. Layer 5 is the same as layer 1 but without ports and with the reactor controller in the center.

The Reaction


To ignite the reaction, a Hohlraum filled with D-T Fuel must be put into the controller. Then, a pulse from a Laser Amplifier of between 400 and 800 MRF (Million Redstone Flux, energy units can be changed by clicking the energy tab in the controller GUI) must hit the laser focus matrix (by default the amplifier will fire with 0 charge, you must either enable redstone sensitivity or set a minimum value for it to work properly). Because one laser will take a very long time to fill the amplifier with this much energy, it is common to have a long chain of amplifiers, each getting charged by lasers on the side and the amplifier behind it.

Sustaining the Reaction

The reactor will accept both Deuterium and Tritium separately, or D-T Fuel. However, only the former can be used to create a sustained reaction with reasonable quantities, the latter will simply use all that is available regardless of injection rate. A D-T Fuel powered reactor can achieve injection rates of up to 1000 mb/t, however a very large supply of fuel is needed to sustain the reaction. The injection rate determines how fast fuel is pumped into the reactor, and thus how much energy is produced. The minimum injection rate for most reactors is 2, for water-cooled reactors it is 4.

Water Cooling

The reactor can also accept water along with fuel. The reactor will convert the water into Steam, which can be used to power an Industrial Turbine.

Additional Information

  • The reactor logic adapter can be used to control the reactors with computers such as from OpenComputers or ComputerCraft
  • As of Minecraft 1.16, players in creative mode can right click on the laser focus matrix with a Configurator to instantly ignite the reactor for testing purposes, without needing a laser pulse.


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