Reactor Airlock Door is the two-block-tall sealed entrance of a reactor room in the Ala Industrial mod for Minecraft 26.2 Java Edition. The door opens only on a rising redstone pulse — a button, a pressure plate or a lever — and never by hand: right-clicking the leaf does nothing. One pulse holds the doorway open for exactly 40 ticks (2 seconds), after which the airlock shuts itself; holding a lever on does not keep Reactor Airlock Door open, because the falling edge is ignored on purpose and only a fresh pulse restarts the timer. A player or mob standing in the gap is never crushed: closing is deferred and rechecked every 10 ticks until the doorway is clear. The leaf does not swing: the panel sinks into the floor over 8 ticks (0.4 seconds), a purely visual trip, since the doorway becomes passable the instant the panel starts moving.

Crafting one door takes a full 3×3 grid: two Shielding Plates and two Reinforced Shielding Plates around a vanilla Iron Door, one Reactor Glass as the upper porthole, two Insulated Copper Cables and one Control Rod Drive — about nine shielding plates, or three palladium ingots, per airlock. Inside a shell the door must form a real doorway: two stacked door cells with the lower half at the interior floor level, otherwise the Reactor Controller reports a missing doorway and the room never forms. Reactor Airlock Door consumes no EU at all — redstone alone drives the mechanism — and works on both Fabric and NeoForge. While the doorway is open, radiation leaks out honestly and the door cannot be clicked or mined, so pulse the airlock only to pass through. For a sealed pulse from inside, the matching Reactor Button (a 20-tick press) was built alongside the door.