Article from NHK News, excerpt :
" The Japanese government has expanded its current 20-kilometer evacuation zone around the crippled Fukushima Daiichi nuclear power plant due to the risks associated with long-term radiation exposure.
Chief Cabinet Secretary Yukio Edano told reporters on Monday that residents in the expanded zone have been asked to evacuate within about a month.
Edano said annual exposure in the zone is expected to be above 20 millisieverts. The worldwide average exposure from the natural environment is 2.4 millisieverts.
The expanded zone includes Katsurao Village, Namie Town, Iitate Village and some parts of Kawamata Town and Minami Soma City.
Edano added that the government will consult with local municipalities. The residents do not have to evacuate immediately.
People in the areas between 20 and 30 kilometers from the plant are now asked to stay indoors or voluntarily evacuate.
Edano said that residents in other areas of the 30-kilometer zone will be asked to prepare for an emergency evacuation. He also said they will need to evacuate on their own. Vulnerable people, such as the handicapped, should be prepared for any contingency."