Reactor Pressure Vessel

Fluid reactor: surround the reactor (with its chambers) with a hollow 5 × 5 × 5 cube made of pressure vessels, hatches and ports. It no longer gives EU: the heat vented by vents is doubled and heats coolant (1 mB of hot coolant per 20 hU); the GUI shows hU/t and both 10,000 mB tanks on the sides. Without coolant (or with the hot tank full) that heat goes back to the hull. Turn it on with redstone on a redstone port; the hatch opens the GUI and lets hoppers in; fluid ports take coolant and hand out hot coolant (with a fluid ejector upgrade they push it, up to 1000 mB/t). From 85% heat the vessel blocks melt and the reactor shuts down.