The primary coolant loop is a closed-cycle system surrounding the reactor chamber that uses pressurised water to transfer thermal energy away from the reactor to the heat exchange.
Fusion reaction is fueled by hydrogen isotopes that are heated to create plasma, which is then excited to reach the energy level required for fusion to begin. The plasma must then be maintained at sufficient density to ensure the reaction remains self-sustaining.
The main function of the reactor chamber is to isolate the reaction from the general environment. The chamber must contain the extreme heat and radioactivity generated by reaction and maintain the vacuum necessary for the reactor to operate.
The choice of primary power source was one of the first technology hurdles that the vessel construction program had to overcome. The power requirements of the main engines and superluminal drive required a significant energy source that also did not have prohibitive mass...
