By "country-worth of mess" do you mean the 20km exclusion zone? The biggest mess to come from Fukushima is the political mess from TEPCO trying to cover stuff up.
And, to answer you question, absolutely nothing (nobody?). However, they don't tend to build power plants on fault lines, so the probability is very low. Similarly low, in fact, to a Magnitude 9 'quake happening directly under Tokyo, and I can guarantee that that would cause a bigger mess.
However, a coal fire power plant is continuously pumping soot, CO2, and a whole host of other unfriendly substances into the atmosphere. A report from last year estimated that coal power kills roughly 13,000 Americans each year.
So, yes, nuclear power is not perfect, but the perceived risk is far greater than the actual risk. This can be blamed, in part, to the scaremongering of the media, but mostly stems from the the fact that the general public does not understand radiation, so is naturally scared of it.
... planetary-scale hazardous installations
Are you aware that nuclear power is safer, in terms of death toll and environmental impact, than both fossil fuels and hydroelectric power? Source
You can even have comments in your code, radical!
By using a language that has lasted through that time to this one: Fortran.
Fortran is still one of the most widely used languages in scientific applications, and is a great starting point for beginners.
Link to Original Source