6 Avril 2016
April 4, 2016
By YURI OIWA/ Staff Writer
Struck by ignorance about the 2011 nuclear disaster, high school science club members in Fukushima Prefecture enlisted the help of fellow students around Japan and abroad for a comparative study on radiation doses.
The results surprised even those living in the prefecture that hosts the Fukushima No. 1 nuclear power plant.
“The individual doses (of external radiation exposure in high school students) were almost equal inside and outside of Fukushima Prefecture, and in European areas,” Haruka Onodera, 18, said in English at the Foreign Correspondents’ Club of Japan (FCCJ) in Tokyo on Feb. 8.
A German correspondent asked her, “Would you declare Fukushima now safe?”
“Actually, we didn’t measure the doses in people living in the contaminated areas, so we can’t say all of Fukushima is safe,” Onodera answered, often pausing in thought in the middle of her words and phrases. “But I hope we will send (personal dosimeters) to contaminated areas and help do risk management for people living there in the future.”
Onodera, a third-year student of Fukushima High School and member of the physics and radiation division of the school’s Super Science Club, also showed explanatory slides at the FCCJ news conference titled, “Fukushima and radiation monitoring. The goal of the project is to show the realities of Fukushima Prefecture to the rest of the world.
The club’s physics and radiation division started the project in summer 2014. It involved 216 high school students and teachers in Japan and abroad carrying personal dosimeters for two weeks.
Six high schools in Fukushima Prefecture--Fukushima, Adachi, Aizu Gakuho, Iwaki, Asaka and Tamura--and another six located elsewhere in Japan--including in Gifu, Kanagawa, Nara and Hyogo prefectures--were involved in the project.
They were joined by 14 high schools from France, Poland and Belarus.
According to the measurements taken by the students, the annual radiation doses in Fukushima Prefecture ranged between 0.63 and 0.97 millisievert. For elsewhere in Japan, the range was from 0.55 to 0.87 millisievert, while in Europe, the annual doses were between 0.51 and 1.1 millisieverts.
The similar levels of external doses are believed to be partly attributable to the lower level of natural background radiation in Fukushima Prefecture compared with that in western Japan. That finding came from an analysis of a database on the radioactive content of soil in areas surrounding the different high schools across Japan.
Onodera, who was seated next to Ryugo Hayano, a professor of physics with the University of Tokyo, at the FCCJ news conference, had also presented the study results last year to a workshop of high school students in France and a conference on Fukushima foodstuffs held on the sidelines of an international food exposition in Italy.
Two second-year students of the Super Science Club--Minori Saito, 17, and Yuya Fujiwara, 17--gave a talk at a workshop organized in Date, Fukushima Prefecture, by the International Commission on Radiological Protection late last year.
First- and second-year students who are members of the club, joined by eight high school students from France, visited peach farmers and shiitake mushroom growers in Fukushima Prefecture in summer last year. It was part of a program for studying the current state of Fukushima from diverse views.
The students wanted to address global audiences after they were shocked by how little was known about the actual state of Fukushima Prefecture.
“Can humans live in Fukushima?” a French high school student asked the Fukushima students over Skype as part of an international exchange program in 2014.
That prompted the Japanese students to determine the actual situation on their own, and compare it with circumstances elsewhere in Japan and abroad. Hayano advised them to undertake the endeavor when he visited Fukushima High School to give a talk.
The findings of the study were surprising. Most of the Fukushima students expected the doses in Fukushima would be the highest, even by a large margin.
The students also studied how behavior affected the dose levels.
The Fukushima High School students were being exposed to lower radiation levels when they were at school than when they were at home. They believe the school’s concrete buildings provided a more effective shield from radiation sources than the wooden houses did.
By contrast, students attending Ena High School in Gifu Prefecture were exposed to more radiation when they were at school, where granite, containing radiation sources, is used in the buildings.
Their analysis results were published in November in a British scientific journal on radiological protection. Onodera was involved in writing the research paper.
“The experience has brought home to me how important it is to address reality objectively and scientifically,” she said.
Onodera said she was growing more interested in basic sciences and dreams of doing research on molecular biology at university.
“We hope to solicit help from people in evacuation zones within Fukushima Prefecture, and from high schools in countries we have yet to address, in further broadening our study,” said Takashi Hara, a teacher and adviser to the science club’s physics and radiation division.