Radioactive contamination of several materials following the Fukushima Daiichi Nuclear Power Station accident

福島第一原子力発電所の事故におけるサイト内のいくつかの物質の放射性核種による汚染

駒 義和  ; 柴田 淳広  ; 芦田 敬 

Koma, Yoshikazu; Shibata, Atsuhiro; Ashida, Takashi

2011年に発生した東京電力福島第一原子力発電所の事故により、放射性核種が環境に拡散し、種々の物を汚染した。発電所サイト内の汚染物,滞留水,瓦礫,土壌と植物に関して公開されている分析データを基にして、放射性核種の汚染ふるまいを検討した。放射性核種の濃度のCsに対する比を損傷燃料の組成により規格化して考察に用いた。瓦礫や土壌へのSrの移行はCsに比べて10から10であり、このような空気を経由した汚染に比べて、滞留水への移行が大きく、Csと同等である。Pu, AmとCmの移行は、Csに比べてごく小さい。ヨウ素、セレンやテルルの移行は、空気と水を経由するいずれについてもCsと同等以上である。HとCの汚染は、Cs, SrやTRU核種と独立しており、異なる移行過程による可能性がある。

Due to the accident of Fukushima Daiichi Nuclear Power Station (NPS) of Tokyo Power Electric Co. in 2011, radioactive nuclides were released to environment and heavily contaminated the NPS site itself. Analytical concentration of radionuclides for contaminated materials including the accumulated water, rubble, soil and vegetation which already opened were utilized to discuss contamination behavior of some radionuclides. The concentration ratio of a radionuclide to that of Cs was normalized with composition of the damaged reactor fuels referred to as "transport ratio" to investigate elemental behavior. The transport ratio of Sr to rubble and soil compared with which was assumed to be via air was approximately 10 to 10, and the successive transport to the accumulated water was comparable to Cs except for the initial release. Transport of Pu, Am and Cm were scarce relative to Cs regardless of transport process by means of air and water, whereas those of iodine, selenium and tellurium were comparable or greater. Contamination with and C was independent of Cs, Sr and TRU nuclides and would be a result of different transport process.