Sellafield

Appears to be a radiation hotspot. The cause of this field is unknown.

Where to find
Spawns in desert biomes.

Dangers
Very radioactive. Creepers can mutate into Nuclear Creepers, and blow up you and everything around you.

Loot
Many versions of Sellafite. If the Sellafite's texture is green, it is radioactive and can be used in the Radiation-Powered Engine to turn it into HE. Alternatively, an Ambience Radiation Generator can be used to gather small amounts of consistent energy.

Trivia

 * At first, it may seem like the Sellafield is just named after Sellafite, irradiated stone that comprises it, but IRL Sellafield is an English nuclear fuel, waste, and decommissioning site that stores and reprocesses nuclear waste. So this structure may be in reference to that site.