Server crashed while walking through the Nuclear Wasteland biome due to ticking world exception:

Crash Report: https://pastebin.com/fZv1DeFi
Nuclearcraft Version: 2.18u
Forge Version: 2854
Minecraft Version: 1.12.2

I have absolutely no idea what is actually causing this as it's such a deep crash, so I'll just remove that piece of the biome decoration code and hope it doesn't look much different :P

Hopefully fixed in 2.18v :)