Fusion reactor

A fusion reactor is a late-game power building that generates plasma for fusion generators. Like nuclear reactors, it gains a neighbour bonus from adjacent operating reactors, but the bonus is based on fluid connectivity rather than heat connections: each adjacent reactor that shares at least one fluid connection increases the energy potential of the generated plasma by 100%. Connecting two outputs to the same reactor does not give any extra benefit. Because each reactor has two fluid connections on each side, the practical maximum bonus while still leaving room to insert fusion power cells is +500%.

The temperature of the plasma produced by a fusion reactor is variable and depends on this neighbour bonus. With no bonus, the plasma is generated at 1 million °C; with a 100% bonus, it is 2 million °C, and so on. In arrays, different reactors can output plasma at different temperatures, and those temperatures average together within the plasma fluid network. Fusion generators then produce power according to the heat of the plasma they consume, up to 50 MW each.

The reactor’s coolant demand does not scale with the neighbour bonus. It always consumes 4/s of cold fluoroketone, modified by quality. This means that adjacent reactors do not require more coolant per reactor than separated ones at the same draw; larger arrays simply need enough fluid throughput and storage in the network to keep both the coolant and plasma circulating smoothly.

Practical ratios for fusion setups are:

• 1 reactor / 2 generators = 100 MW
• 2 reactors / 8 generators = 400 MW
• 3 reactors / 18 generators = 900 MW
• 4 reactors / 28 generators = 1.4 GW

In practice, the main advantage of arranging fusion reactors together is the neighbour bonus, which raises plasma temperature and lets the connected generators output more power from the same basic reactor footprint. Since the bonus depends on adjacency, compact layouts are strongly preferred. The surrounding fluid system also matters: while the coolant consumption stays constant per reactor, the number of pipes and connections increases with larger setups, so the network must be built to handle the extra fluid volume without bottlenecks.

The reactor’s behaviour makes it different from conventional power sources: its output is tied to the temperature of the plasma it creates, and that temperature is determined by how well the reactors are linked. This makes correct placement and connection layout the key to getting the most out of a fusion reactor array.