Unless you give credence to Moller & Mousseau's contested research, Chernobyl's exclusion zone is a wildlife haven.

> Fukushima pollution is all over the Pacific.

Detectable/attributable is not the same as significant. That especially goes for the tritium releases which are a non-event.

> And dismantling is a huge cost that is often left to the state because the operators don't bother factoring it in.

The UK has the https://en.wikipedia.org/wiki/Nuclear_Liabilities_Fund, and in the USA the NRC keeps track of decommissioning funding https://www.nrc.gov/waste/decommissioning/finan-assur.html .

Even then, that may say more of the negative impact of human industry and urbanization on those species and their habitats, as opposed to the safety of any isotopes.