INES Scale Reassessment of the Accident at the Fukushima Dai-ichi Nuclear Power Station

April 22, 2011

On April 12, Japan upgraded the accident at the Fukushima Dai-ichi Nuclear Power Station to a seven on the International Nuclear Event Scale (INES). However, this new assessment does not mean that the situation in Fukushima has worsened. It is based on the latest calculation of the total amount of radioactive substances released, in accordance with the IAEA criteria.

Furthermore, most of the radioactive substances were released in the first few days of the accident and the airborne radiation dose has been gradually declining. For example, radiation levels in Tokyo have never reached a level which would affect the human health, and have been declining steadily. The current data shows that they have returned to a normal level. Radiation levels will continue to be monitored.

The incident in Fukushima differs greatly from the Chernobyl accident. Although the two accidents are assessed as the same level 7, the IAEA has explained that the two differ substantially. First, while the reactor itself exploded at Chernobyl, the reactors at Fukushima automatically shut down and there was no large-scale fire at the site. Second, the total amount of radioactive substances released from the Fukushima plant at present is estimated to be far less than that of Chernobyl. Third, there is neither loss of life by radioactive exposure nor health problem caused by radiation among residents in the vicinity of the nuclear power station.

After the reassessment on April 12, several prominent international organizations determined that excessive measures, such as a general travel restriction to Japan, are not needed. On April 14 and 15 respectively, the International Civil Aviation Organization (ICAO) and International Maritime Organization (IMO) stated, “Radiation monitoring around airports and seaports in Japan continues to confirm that levels remain well within safe limits from a health perspective. In addition, monitoring of passengers, crew and cargo from Japan carried out to date in other countries, in accordance with their national policy, does not suggest any health or safety risk. Therefore, screening of radiation for health and safety purposes is currently considered unnecessary at airports and seaports around the world.” Furthermore, the World Health Organization (WHO) stated on April 13, “Public health risks beyond the 30 km evacuation zone around the plant are currently still low. The latest monitoring of radiation levels in air, drinking water and soil reveal declines in all three. Local authorities review restrictions on food sales on a weekly basis. The International Food Safety Authorities Network (INFOSAN) - a joint WHO/FAO initiative - provides regular updates to the 177 countries belonging to the network, one of which is Japan.”

I hope you find this letter informative. Should you have any questions, please contact the Consulate General of Japan at 404-240-4300 or info@aa.mofa.go.jp.

Thank you.

Sincerely,

Takuji Hanatani
Consul General of Japan