Status of Radiation Dose and Radioactive Contamination due to the Fukushima Accident

  • Received : 2015.07.17
  • Accepted : 2016.06.07
  • Published : 2016.06.30


Backgrounds: The accident at Fukushima Daiichi Nuclear Power Plant (NPP), March 2011, caused serious radioactive contamination over wide area in east Japan. Therefore, it is important to know the effect of the accident and the status of NPP. Materials and Methods: This paper provides a review on the status of radiation dose and radioactive contamination caused by the accident on the basis of publicized information. Results and Discussion: Monitoring of radiation dose and exposure dose of residents has been conducted extensively by the governments and various organizations. The effective dose of general residents due to the accident proved to be less than a mSv both for external and internal dose. The equivalent committed dose of thyroid was evaluated to be a few mSv in mean value and less than 50 mSv even for children. Monitoring of radioactivity concentration has been carried out on food ingredients, milk and tap water, and actual meal. These studies indicated the percentage of foods above the regulation standard was over 10% in 2011 but decreasing steadily with time. The internal dose due to foods proved to be tens of ${\mu}Sv$ and much less than that due to natural $^{40}K$ even in the Fukushima area and decreasing steadily, although high level concentration is still observed in wild plants, wild mushrooms, animals and some kind of fishes. Conclusion: According to extensive studies, not only the effect of the accident but also the pathway and countermeasures against radioactive contamination have been revealed, and they are applied very effectively for restoration of environment and reconstruction of the area.


  1. Baba M. Fukushima accident: what happened? Radiat. Meas. 2013;55:17-21.
  2. Hideo H. An evaluation of personal dosimeter for widely distributed $^{134}Cs$ and $^{137}Cs$ by using EGS code. Radioisotopes. 2013;62(6);335-345.
  3. Hayano RS, Tsubokura M, Miyazaki M, Satou H, Sato K, Masaki S, Sakuma Y. Internal radiocesium contamination of adults and children in Fukushima 7 to 20 months after the Fukushima NPP as measured by extensive whole-body-counter surveys. Proc. Jpn. Acad., Ser. 2013;89(4):157-163.
  4. Shinji T, Masahiro H, Suminori A, Atsuyuki S, Ikuo K, Mikhai B. Thyroid doses for evacuees from the Fukushima nuclear accident. Scient. Rep. 2012;2(507):1-4.