2018 Annual Meeting

Presentation information

Oral presentation

VI. Health Physics and Environmental Science » Health Physics and Environmental Science

[3E05-09] Environmental Radioactivity and Dose Assessment

Wed. Mar 28, 2018 10:35 AM - 12:00 PM Room E (R1-311 -R1 Building)

Chair: Takahashi Fumiaki (JAEA)

11:05 AM - 11:20 AM

[3E07] Long term behavior of radiocaesium and tritium off Fukushima

*Michio Aoyama1 (1. Inst. of Environmental Radioactivity, Fukushima Univ.)

Keywords:radiocaesium, tritium, Fukushima Dai-ichi Nuclear Power Plant accident, water cycle

Radiocaesium and 3H data were examned in terms of temporal variation and 3H vs 137Cs activity ratio and 134Cs vs 137Cs acticity ratio. The radiocaesium and 3H activity concentration in surface seawater close to the FNPP1 site showed decreaseing trend for both northward and southward in general. A temporal changes of direct release rates were different between 137Cs and 3H. 134Cs vs 137Cs activity ratio in surface seawater off Fukushima showed excelent consistency which indicate that that main process during the transport is physical dilution by open ocean waters for both radiocaesium and 3H. It is however 3H vs. 137Cs acticity ratio varied much which may indicate evaporation and contribution from river water/sporadic release of 3H rich water from the FNPP1 site.