E.g. in Fukushima, people were forced to move back into their homes, without giving them an option to get compensated instead. Furthermore, engineers pointed out that there were issues with the way Fukushima was built but their concerns were discarded. Human issue again. Fission plants should be built with the greatest care possible and be designed for major natural disasters.
As for advancements in the field: they might have happened but many reactors are still kept running even though their design is outdated. The greatest advances in drawers don't help if you still have ticking time bombs and one of them go off. Another human issue.
Or the entire thing with dumping waste into the oceans, like on the coasts of Somalia, harming the health in the region and destroying the jobs of the fishermen. Another human problem.
Engineers, in general, are very smart people. They can foresee a great deal of things. But they need to be listened to, and it's too easy to operate a nuclear plant without listening to safety concerns of engineers.
What we've got right now is people harming the health of locals and discarding concerns by engineers, and lying to locals and politicians about this, claiming that the engineers didn't have any concerns. Which is a big problem, and a very human one. And if there's a catastrophy, the government bails them out (what about a mandatory 100 billion coverage insurance for nuclear plants??), and treats locals like shit again. No thanks.