Nether reactor

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This article is about the structure. For the block that was required to activate the structure, see Nether Reactor Core.
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This page describes content that exists only in outdated versions of Minecraft.
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This feature only exists in Bedrock Edition before Alpha 0.12.1.
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This feature is exclusive to Bedrock Edition.
Nether reactor
Nether Reactor.png
Consists of

The nether reactor was a player-built structure exclusive to Bedrock Edition which, when activated, spawned large quantities of normally rare or unobtainable items. The Nether Reactor was made uncraftable in Alpha 0.12.1 and replaced with the Nether, and could only be created in older worlds that had unused nether reactors or with inventory editors.


How the blocks were arranged to make a nether reactor.
The last block placed had to be the nether reactor core.

The reactor was constructed by placing gold blocks, cobblestone, and a nether reactor core in the 3x3x3 arrangement shown below. Air blocks were required on the middle and top layers. If the structure was incorrect, attempting to activate the reactor resulted in the client message "Not the correct pattern!".

Activation Messages[edit]

Messages Description
Client message: Active! Activated successfully.
Client message: Not the correct pattern! Cannot activate because incorrect structure pattern.
Client message: All players need to be close to the reactor. All players must be close to the reactor to be activated.
Client message: The nether reactor needs to be built lower down. Nether structure cannot be created because the location of the nether reactor is too high.


The 'Nether Spire'

Tapping the core activated the reactor, sending the client message "Active!". Immediately after activation, a massive structure of netherrack with multiple rooms, referred to as a Nether Spire,[1] was generated around the reactor. The bottom room, which contains the reactor, replaced all blocks other than those of the reactor with air, while blocks in the upper levels remained intact.

Items would begin to spawn within the reactor room, including glowstone dust, nether quartz, cacti, sugar canes, both types of mushrooms, bows, bowls, pumpkin seeds, and melon seeds. Zombie pigmen were also able to spawn. It was advisable to empty out one's inventory beforehand so that no items were missed, other than any weapons used to fight the zombie pigmen (unless playing in peaceful difficulty). During this stage, the blocks that made up the reactor were converted into glowing obsidian, and the core adopted a red texture to symbolize activation. If the player mined the active core, all aspects of the reaction froze.

The reactor cycle would end after 45 seconds, damaging the reactor's structure and changing the world to night. The reactor was replaced with a 3×3×3 box of obsidian containing the core, which adopted a darker, blue-black texture to indicate that the reaction has ended. If the player built a new reactor around the burnt-out core, the netherrack spire would generate, although the rest of the reaction would not take place.


  • That all players were in the range of the reactor's effects on activation.
  • That the reactor was built within the valid range (Y: 4-96).
  • That the player who activated the reactor was standing level with the structure.


Pocket Edition Alpha
September 5, 2012A image of the nether reactor is tweeted by Johan Bernhardsson. At that time, it used iron blocks rather than cobblestone to activate.
v0.5.0Added the nether reactor.
The spire of the nether reactor is made of obsidian.
v0.6.0The spire of the nether reactor is now composed of netherrack.
v0.8.0?The nether reactor now spawns pumpkin seeds.
The nether reactor can no longer be activated at bedrock level.
v0.11.0build 1The day/night cycle now continues upon mining the active core of the nether reactor.
v0.12.1build 1The nether reactor has been made obsolete by the addition of the Nether. While the nether reactor blocks still exist, they serve no purpose.


  • The spire was composed of over 25 stacks worth of netherrack.
  • Excluding the core, any part of the reactor could be mined after activation and it would still function. This way, the player could recycle the expensive gold blocks. It was possible to recover all 4 blocks provided the player worked quickly.
  • Because the spire could not replace blocks past the world border, when the reactor was activated near the edge of old worlds the player would be able to see the time set to night.
  • If the nether reactor core was mined out while the nether reactor is active, the glowing obsidian would not turn into obsidian after the reactor deactivates. This also caused the reactor to stop spawning items and zombie pigmen, and make the day/night cycle freeze at nighttime for several in-game days.