19 Juin 2012
TOKYO (Kyodo) -- The Japanese government failed to make use of maps showing the spread of radiation in the immediate aftermath of the Fukushima Daiichi nuclear plant disaster, prepared by the U.S. government using data collected by U.S. aircraft, sources familiar with the matter said Monday.
The sources said the maps were neither made public nor used for evacuation of residents near the Tokyo Electric Power Co. nuclear plant devastated by explosions in the days after a massive earthquake and tsunami struck the area on March 11, 2011.
From March 17 to 19, U.S. military aircraft collect radiation data over a radius of 45 kilometers from the plant for the U.S. Department of Energy. The data showed more than 125 microsieverts of radiation per hour being spread about 25 km northwest of the plant, meaning people in the area were being exposed to the annual permissible level within eight hours.
Before releasing the data on March 23, the U.S. government provided the data through the Japanese Foreign Ministry to the Nuclear and Industrial Safety Agency under the Ministry of Economy, Trade and Industry on March 18, and to the Ministry of Education, Culture, Sports,
Science and Technology on March 20, the sources said.
The data were not utilized for the evacuation of people as the agency and the technology minister did not forward the data to the prime minister's office and the Nuclear Safety Commission.
A substantial portion of radioactive materials released from the plant is known to have traveled northwest and fallen on the ground. With some residents "evacuated" to that direction, they could have avoided unnecessary exposure to radiation if the date were swiftly published.
"It was very regrettable that we didn't share and utilize the information," Tetsuya Yamamoto, the chief nuclear safety officer of the agency, told reporters.
Itaru Watanabe, an official of the Science and Technology Policy Bureau of the technology ministry, said it was appropriate for the United States, not Japan, to release the data.