1 Mars 2012
http://mdn.mainichi.jp/mdnnews/news/20120301p2g00m0dm031000c.html
TOKYO (Kyodo) -- Radioactive cesium released into the atmosphere in the disaster at the Fukushima Daiichi nuclear power plant amounted to between 30,000 and 40,000 terabecquerels, possibly equal to 20 to 30 percent of the isotope released in the 1986 Chernobyl disaster, a study showed Wednesday.
The study was compiled by a team of researchers from the Meteorological Research Institute of the Japan Meteorological Agency and the Central Research Institute of Electric Power Industry.
According to one estimate, a total of 137,000 terabecquerels of radioactive cesium were released into the atmosphere in the Chernobyl accident.
Researchers at the institutes analyzed the amount of cesium in seawater collected at 79 spots in the Northern Pacific between April and May last year. They then estimated how much cesium-134 and cesium-137 were released between mid-March and early April with the help of a computer model that analyzed how radioactive materials dispersed in the air and sea.
Most of the releases up until early April were into the atmosphere, the study said, consisting of between 15,000 and 20,000 terabecquerels of both cesium-134 and cesium-137.