Nie wieder Sushi, Frankfurter Rundschau, March 20, 2011:

Google Translation

How long does it take for a contaminated area can be inhabited again?

[Renowned radiation biologist Edmund Lengfelder:] There is a rule of thumb: For a nuclide such as cesium-137, the half-life of 30 years. It takes ten half-lives, so you can populate an area again, making a total of 300 years. But in Japan is still added a difficulty: the nuclear fission process, radioactive substances, it is called the radioactive inventory of a reactor. In a boiling water reactor in Fukushima this inventory is 30 to 40 times as high as in Chernobyl, it can thus escape much more radiation. If we summarize it: In Japan, more people are concerned because the population density is higher than in Chernobyl and there is a higher contamination.