About a third of the 225 youngsters who were evacuated from around the Fukushima No. 1 nuclear plant last March but still reside in the prefecture say the disaster made them aware of radiation dangers for the first time, a new survey says.

According to the survey results released Sunday, the youngsters were either 11 or 14 years old.

Only three said they were mindful of radiation before the disaster, while 138 said they haven't bothered to worry about it since, according to the poll, which covered fifth-grade elementary school and second-year junior high school students.

Of those mindful of radiation, 44 percent said they are concerned about dosages near their homes and neighborhoods, 33 percent are worried about food, and 25 percent said they don't know what they should be concerned about, the responses to a multiple-choice question said.

Some 46 percent said they fear radiation and 42 percent said they don't understand it very well, another multiple-choice question said. The survey was held in February and March in cooperation with eight of the 11 Fukushima municipalities in the hot zone.

At least 4,000 of some 16,000 elementary and junior high school students in the 11 municipalities have left Fukushima.

Of the respondents, only 3 percent said they want to take refuge outside Fukushima, while 14 percent said they don't.

The respondents were also asked questions about Fukushima Prefecture's demand to decommission all 10 of the nuclear reactors it hosts.

A total of 46 percent said nuclear energy is necessary for society, while 10 percent said it was only necessary outside Fukushima.

The high percentage of children who learned about radiation only after the disaster struck suggests they only started fearing it after the evacuation, said Mitsuo Yamakawa, professor at Fukushima University.