Originally posted by Rhapsody:

It's basically not any different from burial chambers and surtling cores, though I think burial chambers are guaranteed to have a room for cores since shortly after launch.

I had two burial chambers in my current world with zero cores. I was surprised. In another burial chamber though I found 19 surtling cores which surprised me even more so yea it can definitly happen that there are no cores at all but it can also happen that you find lots of cores.