4. Consequences outside the plant

4.1 Evacuation orders

On March 11, 2011, at 8:50 p.m., Fukushima Prefecture ordered an initial evacuation within a 2 km radius of the plant. This radius was rapidly extended by the Japanese government to 3 km, with the population sheltered between 3 km and 10 km, at 9:23 p.m., then to 10 km on March 12 at 5:44 a.m. and to 20 km on March 12 at 6:25 p.m., representing some 78,000 people, spread over nine municipalities. Evacuation within a 20 km radius took effect on March 15. At 11 a.m. on the same day, the government gave the order to shelter people living between 20 and 30 km away. On March 25, a "voluntary" evacuation was recommended within this radius, involving 62,000 people. Finally, on April 22, on the basis of the first airborne mapping of dose rates (figure