Don't be so dismissive of Chernobyl and Fukushima as freak, one time events.
The causes you mention are proximate causes. The root cause was human stupidity, recklessness, greed, and folly. That's what sank the Titanic. That's what has caused hundreds of oil spills, including Deepwater Horizon and Exxon Valdez. It's what killed thousands of people in Bhopal. Upon inquiry, over and over we find that the operators had plenty of warnings and plenty of measures they could have taken to avoid problems. They just chose not to heed the warnings. The Titanic didn't have to charge ahead at full speed at night. Didn't have to cut straight through a field of icebergs.
In Fukushima's case, that recklessness manifested as several stupid decisions that saved a little money but made disaster certain if a tsunami struck. They did not build a high enough wall. The engineers knew how high it needed to be and told management, but management overruled or ignored them. Then, they didn't maintain the emergency generators. They skimped on several other measures. The people making these decisions had no business taking such gambles on behalf of the whole world. They were incompetent to understand the true risks they were taking. They had no reason to suppose that a tsunami would never hit, but they behaved as if it wouldn't happen. We would never have allowed such recklessness if we'd known. And that's another thing those fools did-- cover it up. They knew others would not approve of the risks they were taking. They knew. But instead of heeding those very legitimate fears, they denied that they were taking huge risks. They behave like ostriches, sticking their heads in the sand so they couldn't see doom approaching. Then they have the nerve to say that they are blameless and no one could have foreseen that a tsunami could be that big. The only way anyone could think that is by ignoring or dismissing most of knowledge ever recorded and studies ever done on tsunamis. They built for 3.1m and increased to 5.7m, and there had already been 8 tsunamis higher than that in the past century. The 2004 tsunami that hit Sumatra was 24m, and at a few points 30m thanks to funneling effects. They might have even tried a bit of propaganda, bribe someone to cook up bad studies showing that tsunamis are never bigger than some relatively small size.
It will happen again. We do have honest asssessment and reporting in many areas, such as passenger airplanes. Nuclear power could be operated safely. The problem is, will nuclear power be operated safely? Fukushima shows us that it won't. People can't be trusted that far. The continued efforts of TEPCO to downplay the disaster and spin it as not really their fault and also not really so horrific after all shows that they haven't learned their lesson and they still don't take safety seriously enough. Covering their asses seems to be more important than coming clean on matters that imperil the lives of thousands. One example of the spin that nuclear proponents put on the issue is number of deaths. I have pointed out repeatedly that you can't use that alone as a measure of how disastrous an accident was. By that measure, a bad bus crash (Prestonsburg, Kentucky, 27 deaths) could rank as a bigger disaster than a major hurricane (Andrew, 26 direct fatalities).
Would you put those TEPCO bozos in charge of a nuclear plant? I wouldn't.