Reactor Airlock Door

alaindustrial:reactor_door

NuclearImplementednuclearreactormultiblockshieldingredstoneautomation

Summary

The Reactor Airlock Door is a two-block-tall shell block and the intended way into the room. The door itself is optional: walling yourself in and mining back out is a legitimate way to run a reactor, and all the shell has to be is sealed. But a door that IS there has to form a real doorway — one lying in the floor is a mistake rather than a choice, and the controller says so while you are still laying blocks rather than afterwards.

The door deliberately does not behave like a vanilla iron door. It cannot be opened by hand and cannot be left open: it opens on a redstone pulse alone and shuts itself. There is no "open forever" state.

How to open it

Why this way. A vanilla iron door stays open for exactly as long as the signal lasts — its fate hangs on whether somebody forgot a lever. For a door that holds a reactor room's seal that is a poor contract. A pulse door turns a broken seal into a two-second event instead of a state that can last for hours.

Waiting for whoever stands in the doorway is required for the opposite reason: the room this is all for is a place the player is meant to be inside. A door that slams shut on the player would be a trap at the one narrow point of the whole build.

The door is always placed shut, even if a signal is already live nearby: otherwise a new door would appear open and the shell would be unsealed at the very moment it was built.

The airlock has a voice of its own rather than the vanilla iron door's — see "Sound" below.

How to send the pulse from inside. Outside, anything will do — a button, a lever, a pressure plate. Inside a sealed room the signal source has to be as sealed as the room, which is why the reactor button shipped alongside the door: the same shielding alloy, a press of = 20 ticks (1 s), half of, so the pulse comfortably fits inside the opening window. A vanilla button works too, but it is wood or stone — exactly what stops existing inside an active room in stage 4. A button on the wall occupies no shell cell and breaks no seal.

How it moves

The door does not swing — the leaf sinks into the floor and rises back out of it, the way an airlock bulkhead does. The travel takes (8 ticks ≈ 0.4 s by default) each way: a fifth of the open window, so the movement reads as machinery without eating the two seconds it exists to give you. The leaf sets off and comes to rest smoothly, with no jolt at either end.

Nothing is needed underneath the room for this. The leaf is only ever drawn inside the doorway itself and simply stops being visible as it descends — there is nowhere to hide it and no need to, because the cell under a door may hold anything at all.

The travel is a purely visual quantity. The open blockstate still flips in a single tick, and passability, mob pathing and the radiation trace all flip with it. The door therefore becomes walk-through the moment the leaf sets off, not when it arrives: 0.4 s of disagreement between "you can already walk through" and "it has already gone" is the price of leaving the redstone contract exactly as it was.

An open door leaves nothing in the doorway — it has no shape at all while open. Two consequences follow. The useful one: an open doorway honestly leaks radiation outward, because the trace stops at collision and there is none. The inconvenient one: while the door is open it cannot be clicked and cannot be mined; two seconds later it shuts and becomes a target again.

The doorway: where a door counts as an entrance

It is not enough for the controller that a door merely exists in the shell. It needs a doorway — two door cells stacked, with the lower one at the room's interior floor level. Anything else is a window, not a way in.

There may be any number of doors: two — an entrance and an exit — is an ordinary layout. The requirement is exactly one: at least one real doorway.

Energy

The door runs on redstone, not EU/FE. The drive inside it needs no power — it was paid for at the crafting table.

Block properties

The two halves live and die together: break either and the player gets one door while the other half disappears. Mobs may path through the door only while it is open.

hinge is a leftover from the swinging version. A sliding door has no hinges and the flag changes nothing about how it looks in any position. It was kept on purpose: dropping it from the set would change the blockstates of doors already built in other people's worlds, and that is too high a price for retiring one unused flag.

The leaf is drawn by a block renderer rather than by a baked model — a model that only has two poses cannot show the movement between them. The cost: the door has no ambient occlusion, and no crack overlay is drawn while it is being mined.

The door carries formed like the rest of the shell — the controller writes it into every cell of a finished room (see "The seamless look"). Unlike casing and glass, it does not change how the door looks: the leaf has no seamless texture of its own. The property exists for uniformity — neither the scan nor the flag sweep should have to know which shell block happens to have a cosmetic variant.

powered is stored for exactly one purpose — telling a rising edge from "the signal is still on". Without it, every neighbour update with the lever on would read as a fresh pulse, and the door would re-open the instant the player watched it close.

Sound

The airlock door has a voice of its own instead of the plain iron one: opening hisses as the seal vents, closing snaps the pneumatic lock shut . It never uses the vanilla iron-door sounds in either position — you can hear that this is the way into a reactor hall, not into a cellar.

Recipes

Craft — ×1 at a time, on a full 3×3 grid.

P G P P = shielding plate ×2
W D W G = reactor glass ×1
R V R W = insulated copper cable ×2
D = iron door ×1
R = reinforced shielding plate ×2
V = control rod drive ×1

The recipe reads as the block's construction: a vanilla iron leaf in the middle, dressed in shielding alloy — plain plates across the top, reinforced ones across the bottom — with reactor glass becoming the round porthole of the upper half, two insulated copper cables bringing power in, and the drive in the bottom row turning the leaf into an airlock.

The drive is a separate item: 3 shielding plates, 2 iron ingots, an electronic circuit, 2 tempered iron plates and a piston

Progression

Tier: none. Requires: two shielding plates, two reinforced shielding plates (see casing — the full chain is described there), one piece of reactor glass, two insulated copper cables, one vanilla iron door and a control rod drive. Unlocks: a proper way into a formed room — the only way in and out that does not take the shell apart.

The drive appears here for the first time but not the last: it is also part of the controller, and in stage 2 it gets its real meaning — regulating how deep the fuel rods sit.

Related

Reactor Casing — the rest of the shell and the material chain. Reactor Controller — what checks for a door and a doorway. Reactor Button — how the pulse is sent from inside the room. Reactor Glass — a window, which is not a door. Thermal Centrifuge — the precedent for "redstone as a machine's control", with the opposite contract: there the signal must be held.

Crafting

Shaped Crafting

iron d

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Reactor Airlock Door