![Thumbnail Unactivated reactor core inside the necessary reactor structure [sitting atop an existing nether spire (not required)]. Make sure you are at the same y-level to activate.](https://media.forgecdn.net/attachments/1564/412/img_6583-png.png)
Unactivated reactor core inside the necessary reactor structure [sitting atop an existing nether spire (not required)]. Make sure you are at the same y-level to activate.

Freshly activated reactor core (mine the gold quick, but don't mine the spire!).

It's glowing bright now. You'd better mine that gold.

You waited too long to mine the gold (around 6 seconds)!

You missed the gold, but maybe there's still something valuable to get out of it.
![Thumbnail Mining/moving the active core will stop the reaction more gently. Now you can mine the glowing obsidian, keep the active core for decoration or reuse, or reuse the intact spire. [Just be careful not to agro the zombified piglins (not pigmen)].](https://media.forgecdn.net/attachments/1564/417/img_6588-png.png)
Mining/moving the active core will stop the reaction more gently. Now you can mine the glowing obsidian, keep the active core for decoration or reuse, or reuse the intact spire. [Just be careful not to agro the zombified piglins (not pigmen)].

Dormant core in degraded spire. Can be reused again as a reactor core or for decoration.

Top: End reaction; Unable to connect (core still preserved). Bottom: Nether reaction; Runaway reaction if disturbed or not stopped (core destroyed unless moved/mined in 45 seconds). Does not replace non-air blocks, unlike overworld clearing.