Is this region comparatively unspoilt because of the Chernobyl disaster? If so, that's a strange kind of irony.
There's no industry, almost no trade, population is sparse, and even farming isn't very profitable there. And for some weird reason it's not even that well known by tourists.
Region influenced by Chernobyl is just a small part and it wasn't the root cause anyway.
edit: Cranberries!
If you are a billionaire and you want to make a wildlife preserve with your billions, just buy some dirty bombs.