This natural background radiation is not harmless, as the effects
of high exposure to cosmic background radiation (e.g. by frequent
trans atlantic flights) or high radon levels in homes or local soil
on cancer incidence have shown. [85, 86, 87, 88] It can be assumed
that a certain proportion of the 'naturally' occurring cases of cancer
are caused by constant exposure to 'natural' background radiation
"There have been no acute radiation syndrome fatalities reported due to the Fukushima accident, while approximately 18,500 people died due to the earthquake and tsunami. Future cancer deaths from accumulated radiation exposures in the population living near Fukushima are predicted to be extremely low to none."
So why are we talking about the radiation here? The effect is meaningless in comparison. Why aren't we talking about what to do about tsunamis?
Future cancer deaths from accumulated radiation exposures [...] are predicted to be extremely low to none. Yes, but I find the paragraph in the source 
Even the worse case scenario — a dose of 50 mSv — poses a fairly minimal risk.
However, the models showed that infants living in Namie could have got a higher
dose to their thyroid, of 100–200 mSv. That higher dose would be due mainly to
radioactive iodine-131 blowing from the plant immediately after the accident. Brenner
says a dose of 200 mSv to a female infant under a year old might mean a 1% risk of
developing thyroid cancer over her lifetime (by comparison, the lifetime risk in the
United States is 0.02%).
So I think that a argument can be made for nuclear energy, but this argument should not be "no one will ever know we killed her. <evil laughter>" The argument should include sentences like :
[...] My offers were such as to give me a risk equivalent to that faced by an American soldier
in World War II, according to my calculations of plutonium toxicity which followed all generally
accepted procedures. These offers were made to all three major TV networks, requesting a few
minutes to explain why I was doing it. I feel that I am engaged in a battle for my country's
future, and hence should be willing to take as much risk as other soldiers.
Tsunamis are not much of a disaster without man building and living along the coast where tsunamis may strike. The circumstances of the disaster are just as much man made as the radiation.