People who are the most concerned about nuclear energy understand these facts:
1) High-level radioactive waste is deadly to touch, hold, carry, etc., for hundreds of thousands of years. You can pick up a piece of this waste, hold on to it for a while, and be dead in a few days. Perhaps you picked it up, studied it for a while, and dropped it in the space of 15 minutes because it was sitting a pile of rocks.
2) Homo sapiens, our species, is believed to be between 100,000 and 200,000 years old.
3) We've only had writing for about 5,000 years, and in certain countries in sub-Saharan Africa only about half the population is literate in ANY language. Before the modern era, it's thought that no more than 40% of the world population was literate.
4) As we all know, the most advanced civilizations decline and are sometimes replaced by primitive civilizations. Among many other causes, formerly fertile land can become arid. Formerly great civilizations in Central America are now jungle with isolated tribes. Formerly fertile Northern Africa is a now great desert habited by nomadic people and not much else.
5) The world is ignorant about geology. We have no idea how to do fracking safely, even though it could probably done safely. The reason is we don't have enough understanding about how the ground beneath our feet works.
Nuclear energy, in its present form, produces a waste product that will outlive our species. We all hope that Homo sapiens will evolve into a better species, but there is no guarantee of that. Perhaps there will be a Homo successor that is more primitive. We can guess what that species will be like, but we're just guessing. It is of paramount importance that we are able to communicate with that successor species. Then we need to find a place to put the waste on Earth that is geologically sound, yet we can't even drill for oil safely without causing earthquakes. Good luck with that.
The inevitable will happen and the waste will somehow surface. Let's say that there is ample signage. How good are you at Sumerian cuneiform? I'm not so good at it, either. In fact, I don't even know a single symbol. At one time cuneiform was the premier go-to language, the English of its day, and it is only about 5,000 years old, give or take a few thousand years. If radioactive waste was labelled in cuneiform, I'd have to retain a scholar to understand the risk of the material. Can you even imagine how dissimilar a language 500,000 years from now will be from English? That's 100 times as long as the whole history of writing.
We're kidding ourselves by thinking this energy is clean. What we are doing, actually, is poisoning the land for hundreds of thousands of years. The built-in assumption exists that we'll be so advanced techologically speaking by then that future residents of Earth will have no problem dealing with any of it. In fact, I believe that the oppposite is true. We can't depend upon steady progress. Progress has always been in fits and starts, with intense periods of decline, and at times entire civilizations have dropped off the face of the Earth.