Long-term impact on the marine environment; Simulation of the marine dispersion of released radionuclides from Fukushima-Daiichi Nuclear Power Plant and estimation of internal dose from marine products

長期的な海洋環境影響は?; 福島第一原子力発電所からの放出放射能の長期的海洋拡散シミュレーションと海産物摂取による内部被ばく評価

中野 政尚 

Nakano, Masanao

As a result of the accident at Fukushima Daiichi Nuclear Power Plant caused by the 2011 Off the Pacific Coast of Tohoku Earthquake and tsunami on March 11, radioactive materials were released into the environment. A global scale calculation of the long-term diffusion of radioactive materials in ocean using long-term assessment model for radioactivity in the oceans (LAMER), which is a calculation code developed by Japan Atomic Energy Agency, was conducted to estimate their concentration in seawater and the exposure dose caused by seafood ingestion. When we postulate that 8.45 PBq of Cs has been released, the calculation of the Cs concentration in seawater after April 2012 would be a maximum of 23 Bq/m, which is 14 times more than the concentration originated from atmospheric nuclear tests before the accident. The highest concentration continued to decrease after that point of time, and it will be of the same level as the concentration originated from the nuclear tests by 2023. Moreover, internal exposure from I, Cs, and Cs caused by seafood ingestion was calculated to be a maximum of 1.8 Sv/y, which is approximately equal to the past yearly dose derived from the atmospheric nuclear tests.