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Tsumune, D. ., Central Research Institute of Electric Power Industry, Abiko, Japan, tsumune@criepi.denken.or.jp
Tsubono, T. ., National Center for Atmospheric Research, Boulder, USA, tsubono@ucar.edu
Aoyama, M. ., Meteorological Research Institute, Tsukuba, Japan, maoyama@mri-jma.go.jp
Hirose, K. ., Sophia University, Tokyo, Japan, hirose45037@mail2.accsnet.ne.jp

DISTRIBUTION OF 137CS FROM THE FUKUSHIMA DAIICHI NUCLEAR POWER PLANT SIMULATED NUMERICALLY BY A REGIONAL OCEAN MODEL

Radioactive materials were released to the environment from the Fukushima Daiichi Nuclear Power Plant as a result of the reactor accident after the Tohoku earthquake and tsunami of 11 March 2011. The two major likely release pathways from the accident site, i.e. direct release of high radioactive liquid wastes and the atmospheric deposition, existed. By analysis of the 131I/137Cs activity ratio, we determined that direct release from the site contributed more to the measured 137Cs concentration than atmospheric deposition did. We then used a regional ocean model to simulate the 137Cs concentrations resulting from the direct release to the ocean off Fukushima and found that from March 26 to the end of May the total amount of 137Cs directly released was 3.5 ± 0.7 PBq. Further, the simulated temporal change in 137Cs concentrations near the Fukushima Daini Nuclear Power Plant site agreed well with observations. Our simulation results showed that 137Cs concentrations decreased to less than 10 Bq L-1 by the end of May 2011 in the whole simulation domain as a result of oceanic advection and diffusion.

Session #:088
Date: 2/21/2012
Time: 14:45
Location: Ballroom E

Presentation is given by student: No