Thursday, November 17, 2011

Half of radioactive materials from Fukushima fell into sea: study - 17th Nov 2011

More than half of the radioactive materials that were emitted into the atmosphere in the days after the Fukushima nuclear disaster have since fallen into the ocean, according to a recent simulation by a team of researchers.

Between 70 and 80 percent of the radioactive cesium from the Fukushima Daiichi power plant in Fukushima Prefecture had fallen into the sea by April, with the rest having fallen on land, according to the simulation done by the Meteorological Research Institute in Tsukuba, Ibaraki Prefecture, and other researchers.

"The Fukushima nuclear power plant is located on the eastern edge of Japan, so only small amounts ended up falling on land because (such materials) get carried by the westerlies between March and April," said Yasumichi Tanaka, a senior researcher at the Japan Meteorological Agency institute and a member of the research team. However, it suggests the fallout that did not make landfall polluted the ocean, he added.

A simulation model applied in the study was developed by the institute and the agency, and was used to see how such radioactive isotopes as cesium-131, cesium-134 and cesium-137 got dispersed in the days after the disaster triggered by the March 11 earthquake and tsunami.

On the premise that the materials were dispersed with each particle being the size of less than 1 micrometer, the simulation showed they largely completed a trip around the globe in roughly 10 days after first crossing the Pacific. Read More