The reason radioactive materials take so much care IS that they can be quite dangerous. Too simplistic an answer? Sure, and I know that many other things we deal with can be dangerous when not controlled and regulated- cars, electric power lines, dogs, stepladders...etc.

The difference is in scale. One car or unleashed dog or carelessly used stepladder can hurt a few people, and perhaps damage some property. One nuclear power plant can destroy the lives of tens of thousands and affect millions of others.
We KNOW that some dogs will bite, and sometimes cars will go astray, and sometimes a stepladder will break or be used carelessly...but we know that the benefits far out rank the risks, and tolerate them.

It is not reasonable to assume that nuclear power can be made 100% safe, and we have 3-4 serious examples of why...and several near misses.

The cost-benefit analysis is getting fuzzy, and there's no reason to assume there won't be MORE events like Fukushima and Chernobyl.

Those butterflies? They should be viewed like canaries in the coal mine and be a warning to shift our priorities soon!