Scientific Reports | Article Open
Isotopic evidence of plutonium release into the environment from the Fukushima DNPP accident
Jian Zheng, Keiko Tagami, Yoshito Watanabe, Shigeo Uchida, Tatsuo Aono, Nobuyoshi Ishii, Satoshi Yoshida, Yoshihisa Kubota, Shoichi Fuma & Sadao Ihara
Article number: 304 doi:10.1038/srep00304
Received 12 January 2012 Accepted 17 February 2012 Published 08 March 2012
The Fukushima Daiichi nuclear power plant (DNPP) accident caused massive releases of radioactivity into the environment. The released highly volatile fission products, such as 129mTe, 131I, 134Cs, 136Cs and 137Cs were found to be widely distributed in Fukushima and its adjacent prefectures in eastern Japan. However, the release of non-volatile actinides, in particular, Pu isotopes remains uncertain almost one year after the accident. Here we report the isotopic evidence for the release of Pu into the atmosphere and deposition on the ground in northwest and south of the Fukushima DNPP in the 20–30 km zones. The high activity ratio of 241Pu/239+240Pu (> 100) from the Fukushima DNPP accident highlights the need for long-term 241Pu dose assessment, and the ingrowth of 241Am. The results are important for the estimation of reactor damage and have significant implication in the strategy of decontamination.