Reactor Controller

Open the controller by right-clicking the block when it sits on a side face of the casing (not top or bottom), replacing a casing block on the outer frame with the screen facing outward.

New to multiblocks? Start with Getting started.

Operation

• Validate / run — first open runs validation; when valid the reactor can turn ON and show RF/tick, fuel, and coolant readouts.
• Fuel — move fuel between your inventory and rod storage when slots are shown.
• Coolant fluid — view level and fill/drain when controls are provided (optional for RF-only play with an empty coolant buffer).
• Reboot — re-validates the structure and refreshes port tank sizes after you change the build or port settings.

Stopping without breaking the multiblock

Use a Reactor Redstone Port if you want external redstone to hold off or stop operation while the shell stays formed. Without a redstone port, the reactor runs whenever it is valid and ON (no redstone gate).

If stability readouts are enabled for your pack, they appear here — see Reactor instability.

Reactor valid but not producing?

Check
Power port present and cabled?	RF needs a Power Port with something accepting energy on the outside.
RF-only mode?	Empty coolant buffer = no fluid required; water/steam mode needs coolant + extract path.
Redstone port?	Reactor may stay OFF until the port’s mode + signal allow run.
Waste backing up?	Add an EXTRACT Resource Port or empty waste manually.

Tooltips and the status line on this screen explain the current state.