2014 年 49 巻 3 号 p. 157-160
The magnitude of dose due to the Fukushima Daiichi Nuclear Power Plant accident was revealed by the UNSCEAR 2013 report published in April 2014. In the report, effective doses and thyroid doses were estimated for 1-year-old infants and 10-year-old children as well as adults. The UNSCEAR Committee formally agreed to rely principally on data available and literature published before the end of September 2012. However, studies on dose estimation have been conducted after that. Then, recent papers and activities of “Fukushima Health Management Survey” are presented. In relation to this, the effective dose estimated by the UNSCEAR report was compared with the estimation by another method (extrapolation from the result of Fukushima Health Management Survey with data on individual dose measurements using personal dosimeters). As a result, they were generally consistent each other. The UNSCEAR report states, it is likely that some overestimation has been introduced generally by the methodology used by the Committee. In the case of internal dose, direct measurements of the radioactive content of the thyroid indicated doses being lower than those estimated by the Committee, by a factor of about 3 to 5. Thus, studies on reconstructing a more realistic dose for residents are still needed.
