South Korean environmentalists hold umbrellas beside jets of water during a rally demanding South Korean government to stop expanding nuclear power plants in Seoul, South Korea, Wednesday, April 6, 2011. Fears over possible radiation contamination are growing in South Korea, the country closest to Japan, after Japanese nuclear power plants were damaged by earthquakes last month.(AP Photo/Ahn Young-joon)

Photo by: Ahn Young-joon

South Korean environmentalists hold umbrellas beside jets of water during a rally demanding South Korean government to stop expanding nuclear power plants in Seoul, South Korea, Wednesday, April 6, 2011. Fears over possible radiation contamination are growing in South Korea, the country closest to Japan, after Japanese nuclear power plants were damaged by earthquakes last month.(AP Photo/Ahn Young-joon)