Nothing man-made is "completely safe". No such thing.

However, nuclear energy is the safest form of energy production we have.

By far.

And that includes Chernobyl and Fukushima.

People overestimate the danger from nuclear energy by incredible amounts.

That doesn't mean that close exposure to a running nuclear reactor won't kill you in short order. That's why we build these things with shielding. A lot of other things will kill you in short order if exposed to them: cars/trains in motion, for example.