Update on Radiation from Fukushima:http://www3.nhk.or.jp/daily/english/23_35.html
Radiation could affect people outside 30km zone
Chief Cabinet Secretary Yukio Edano says computer forecasts show that radiation leaking from a nuclear plant could pose a hazard to people outside its 30-kilometer zone.
Edano said at a news conference on Wednesday that a computer forecast system has shown that radiation levels in some areas outside the 30-kilometer zone would exceed 100 millisieverts, which is the level that could affect the human thyroid if a person is exposed to it outdoors for 24 hours.
Edano cited a lack of data and the need for more precise calculations, and said there is no need for immediate evacuation or to seek shelter indoors.
At the same time, he urged people living downwind from the plant to stay indoors as much as possible and keep the windows shut as a precaution.
The computer system, called SPEEDI, predicts how radioactive substances will spread in case of radiation leakage from nuclear power plants, based on measurements taken at various locations, prevailing winds and other weather conditions.
SPEEDI data can be used to draw up evacuation plans for residents around power plants in case of accidents.
Wednesday, March 23, 2011 18:55 +0900 (JST)