Nuclear reactors are extremely dangerous, any accident could create a serious threat to anyone and for a long period. That's not nothing now, until today several examples make clear that the risk is high. The planet has multiple processes, and in any situation these extremely delicate facilities are more than vulnerable, so there's always the possibility of making any natural disaster even worse.
If handling explosives is dangerous, radiation surpasses this level until a much higher degree. There was a time when atomic bombs were tested in areas near population. Now, the critical health effects of radiation are known, but even this way, there are intentions of using nuclear energy inside the planet. How the potential danger is too high and the Sun provides enough energy for millions of human civilizations, this energy should be left untouched. That's obvious: first take all the clean energy that the star provides each second and after, if there's no other solution, start to think in other sources. Is this puerile reasoning not right?
Other great problem of nuclear plants is the enormous quantity of nuclear waste, always very worrying in terms of environment. Diachronic individuals are proposing theories about the methodology of treating this waste, with an evident chance of misconceptions, failures and then annoyances to the planet and its inhabitants. Nuclear waste is perhaps the worst, some active for thousand years. Other certain nuclear waste elements are far ahead, with more than two million years active.
The nuclear waste needs to be stored, transported and placed in “safe locations”. Any of these operations could end in a tragedy with too many years of consequences.
For these reasons nuclear power is not a sign of development but a cave full of monsters. Lamentably some countries are using reactors to manufacture weapons, making the world unsafe, and thinking in terms of defense & attack like in ancient epochs. There's always the opportunity of evolving, without these realities in the list.