I think you're talking about the Academy of Sciences, in their review of the Biological Effects of Ionizing Radiation report. Here's my layman understanding: for many years, this authoritative basis for nuclear safety regulation recommended a precautionary adherance to LNT (linear no-threshold), a heuristic that states that small doses of radiation carry smalll risk, corelating to the linear relationship measured at higher doses. The latest review of this important report admitted doubt over the validity of linear models at low doses.
I'm not certain how relevant this is to the fukushima disaster. Certainly, many people are today living in radiation levels well above those which defined the Chernobyl exclusion zone. I guess the abandonment of LNT has fed into the WHO calculations, that actually don't say there will be no deaths, just that the deaths due to the fukushima reactor disasters will not be discernable from cancers expected to occur in the population over the next lifetime due to other causes.
I'm not certain how relevant this is to the fukushima disaster. Certainly, many people are today living in radiation levels well above those which defined the Chernobyl exclusion zone. I guess the abandonment of LNT has fed into the WHO calculations, that actually don't say there will be no deaths, just that the deaths due to the fukushima reactor disasters will not be discernable from cancers expected to occur in the population over the next lifetime due to other causes.