I'm not that familiar with the geography of Kyiv, but it seems unwise to keep radioactive waste anywhere near a population center. Is this a permanent holding facility?
Radioactive waste is regularly stored at the reactor that burned it. Those supply electricity for population centers, and thus are placed in proximity. I think you'd be surprised at how it works in practice. If your interested in learning more, there's some great info from the Fukushima plant meltdown, very transparent and public incident that gives insight into how things work in this space.
Update: they hit a fence. The facilities are intact.
That's why this crisis is a major risk for Europe right now. One shell in a wrong place and Chernobyl 2.0 is happening. The nuclear tech has improved there but not that much. There are still reactors with no concrete structure encapsulation.
Weren’t Chernobyl’s remaining reactors shut down on 2000? That would presumably make the risk from an accident similar to that from dirty bomb (so localised) not a nuclear meltdown.