Use stone first

We have snuggly place

I like last comment. And suddenly it doesn’t counts.

You mean water under ground? It was in contact million years before any of us was born.

This doesn’t even factor the space abandonned to store «normal» toxic materials.

You mean under ground from where it was dug out?

Disproven by Russia. Maybe sometimes core is replaced because it uses unsafe design by current standards like in St. Petesburg.