"properly sequestered" is the key word. There is no such thing.

Here in Germany, we still have not found where to put nuclear waste long-term, and there is no solution in sight.

Even if one day we find one, how do we communicate the potential dangers of nuclear waste to a civilization that is supposed to understand what we're communicating in 30000, 50000 years? With a fancy unicode symbol, like U+2622?

We have no idea what people 3000 years ago were trying to tell us with their fancy symbols.

Nuclear energy is the analogy of tech debt that can never be paid back, ever.