One way to look at it

I was skimming through an article titled "The mystery of Chernobyl" about how wildlife seems to flourish in areas of nuclear fallout. I think this is an interested take on that:

The natural world "would welcome nuclear waste as the perfect guardian against greedy developers… the preference of wildlife for nuclear-waste sites suggests that the best sites for its disposal are the tropical forests and other habitats in need of a reliable guardian against their destruction by hungry farmers and developers" - James Lovelock, the creator of the Gaia theory

I mean, the only benefit of those radiation levels that I can see is the exclusion of humans from the area. Just because the bear population is larger in the exclusion area than outside (mentioned in the article), does not mean that they are healthy populations. It may just mean they do not face competition for resources. Some people think the Gaia theory is a little cooky, but it is something to think about.