The basis of so much concern and cost around nuclear power devolves from the belief in the linear no-threshold theory of the risk from low level radiation, but is it accurate?
We have a good idea of the effects of high levels of radiation exposure from nuclear bomb survivors in Japan, but determining if low level exposure creates a heightened cancer risk can be difficult. Human biology has evolved to constantly repair damage done to DNA by natural radiation and cell metabolism.
It also appears that the number of hits on cells is not the determining factor in cancer occurance.
So are we operating on a false premise when it comes to the main risk seen around large scale nuclear power production?There is plenty of very direct and obvious evidence on this. For example, the number of initiating events is roughly proportional to the mass of the animal; more DNA targets means more hits. Thus, the simple theory predicts the cancer risk to be proportional to the mass of the animal. But experience indicates that the cancer risk in a given radiation field is roughly the same for a 30 gram mouse as for a 70 000 gram man, and there is no evidence that elephants are more susceptible than either.
If only the number of hits (which is proportional to the number of initiating events) were relevant (regardless of the mass of the target), then our very definition of dose in terms of radiation hits per unit mass of the target would be misleading. Another obvious example of the failure of the simple basis for the LNT is in the spectacular increase in cancer incidence with age. Young people experience cancer initiating hits as frequently as old people, but the probability for a cancer to develop is much higher in old people.
Most exposure is only going to be at low levels except in the most extreme events, as we can see from Fukushima it took a historical level tsunami to initiate a large release of radioactive material.