niveau de radioactivité constaté extrêmement élevé sur des bâches, recouvrant une cour d école primaire à Tokyo

Un niveau extrêmement élevé de césium radioactif a été détecté sur des bâches, recouvrant une cour d'école primaire à Tokyo.

Des fonctionnaires de l'arrondissement de Suginami ont mesuré 90 600 becquerels de césium radioactif par kilo sur les bâches en question. Elles avaient été étendues pour protéger le gazon de la cour contre le gel entre le 18 mars et le 6 avril. A noter que l'école se trouve à environ 230 kilomètres de la centrale de Fukushima.

Le niveau de radioactivité constaté est plus de 11 fois supérieur aux 8000 becquerels par kilo, définis par le gouvernement comme limite pour l'élimination des déchets par enfouissement.

La municipalité envisage d'incinérer les bâches avec les autres déchets.

An extremely high reading of radioactive cesium has been detected on a groundsheet at an elementary school in Tokyo.Officials of Suginami Ward detected 90,600 becquerels per kilogram of radioactive cesium on the sheet. It was used to protect the school lawn against frost from March 18th to April 6th, soon after the Fukushima nuclear accident. The school is located about 230 kilometers from the nuclear plant.The sheet's radioactivity level is over 11 times the government's 8,000 becquerels-per-kilogram limit for disposal by burying underground.The city is considering incinerating the sheet with other garbage.The school stored the sheet next to a gymnasium until early November. Ward officials who measured radioactivity near the area where the sheet was kept detected 3.95 microsieverts per hour at about one centimeter above the ground.A mother whose son and daughter attend the school said she is worried that contamination from the nuclear plant is reaching Tokyo, despite the capital's distance from Fukushima. She says she wants a thorough inspection of the school building, including windows and gutters.

Simulation césium radioactif

http://www3.nhk.or.jp/nhkworld/french/top/news.html

A team of researchers says radioactive cesium discharged from the damaged Fukushima Daiichi nuclear plant may have contaminated soil in Hokkaido and areas of western Japan more than 500 kilometers from the plant.The international team, including researchers from Nagoya University, simulated the spread of radioactive materials. They combined global atmospheric patterns with nationwide radioactive measurements taken over one month from March 20th, 8 days after a hydrogen explosion at the Fukushima plant.The researchers say the results suggested that some cesium-137 had reached the northernmost island of Hokkaido, and the Chugoku and Shikoku regions of western Japan.They say the radioactive material may have accumulated in the soil due to rain.Cesium-137 has a half-life of 30 years.But the research team says the pollution is not high enough to require decontamination.The radiation density per kilogram reached 250 becquerels in eastern Hokkaido, and 25 becquerels in mountainous areas of western Japan.Nagoya University professor Tetsuzo Yasunari says the simulation suggested cesium had dispersed across a wide area. He called for a nationwide testing of soil, and warnings of hot spots where radiation levels are high.