福島第一原子力発電所の事故後に発行された文部科学省の放射線副読本の内容分析

抄録

  After the Fukushima nuclear accident in March 2011, the Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT) issued new educational materials (supplementary readers) on radiation for school children in November 2011. The readers were revised in 2014 and then again in 2018. They provide information focusing on situations after the accident, scientific knowledge on radiation, and the progress of recovery in Fukushima Prefecture. On the other hand, the readers have received much criticism from teachers and citizens, including that there is little information on the facts and lessons learned about the accident. In order to objectively and quantitatively clarify the characteristics of the Japanese government's supplementary readers on radiation, content analysis was applied. As the result of the text mining and sentiment analysis, the following characteristics were clarified: 1) the most frequently appearing word is “hoshasen” (radiation) in each reader; 2) “shizen” (nature) is seen to have a stronger co-occurrence with “hoshasen” (radiation) in the 2011 and 2018 readers when compared to the 2014 edition; 3) positive words “riyou” (use, noun) or “tsukau” (use, verb) ranks within the top 20 words which have most strongest co-occurrence with “hoshasen” (radiation) in the 2011 and 2018 readers; and 4) the negative word “osen” (contamination) was nearly deleted from the text in of the 2018 edition, that is, removed from the 2014 version. The results of content analysis indicate that the explanation of natural radiation increased again in the 2018 reader, similar to that of the 2011 edition, while the words describing the actual pollution caused by the Fukushima nuclear accident were deleted.