One thing all the world’s nuclear reactors have in common is that – unless they are constantly cooled with large volumes of water – they will eventually explode. This is because even after nuclear fission has been stopped, the decay heat from the fuel rods is sufficient to melt them and prompt dangerous interactions between water and their zircaloy cladding.
It seems highly likely that many more nuclear reactors will be built around the world, prompted by factors including concern about climate change, worries about fossil fuel availability, and the enthusiasm of states for nuclear technology. Today’s reactor designs suffer from the risks mentioned above. I don’t know how feasible it would be to design reactors which are passively safe (and which will automatically enter a safe state, without human action, after a major accident), but it seems worth investigating seriously. It seems much more prudent to build machines that slow down and cool off when left alone, rather than those that heat up unstoppably until their liquified contents melt through the containment around them and poison the nearby environment.