A fusion reactor is exactly the opposite of a Fission Reactor. Instead of splitting atoms to generate electricity it fuses atoms together to form a heavier one, which releases energy in the process.
To start the fusion reactor, one must pump 50 Kilowatts, or 50,000 Watts of electricity, into the main reactor. Once reaction is initiated, it will generate plasma around it and cause a fusion reaction, creating a massive amount of heat around it which is absorbed by Electromagnets. This heat is then used to heat water, which is turned to steam and powers the turbines. If the plasma were to escape into the air, it would incinerate anything it touches. Fusion reactors can be extremely dangerous if not set up properly. The plasma must be locked inside of a combination of Electromagnets and Electromagnetic Glass to prevent the plasma from getting out and setting fire to your world.
The Electromagnet must be the block that is sandwiched between the Electromagnetic Glass enclosing the plasma. Using only a single type of block will produce unwanted results. It is possible for two reactors to share part of the outer Electromagnet shell, saving the player from building more expensive Electromagnets.
By placing a powered Manipulator adjacent to the reactor, it is possible to automatically insert Deuterium into it. This allows for the Fusion Reactor to be entirely automated with the appropriate set-up.