I wanted to see just how strong these nukes were...
I built a cube with 5-block-thick obsidian walls around 1 nuke. It hollowed out a few obsidian blocks, but I was hoping for something a little more spectacular. So, I put 3x3x3 nukes in the middle and patched the walls. I, uh, got disconnected when my client couldn't keep up.
If you didn't notice, obsidian is no longer indestructible. It's still safe from conventional explosives, but not nukes...