June 30, 2025  1st IER seminar of FY2025 was held. <Project Associate Professor Gusyev, Professor Takata>

Institute of Environmental Radioactivity (IER) regularly holds the IER seminar in which the faculty members report on their research results, with the aim of facilitating their research activities and promoting communication.

In the 1st IER seminar of this fiscal year that was held on June 30, 2025, two presentations were given by Project Associate Professor Maksym GUSYEV and Professor TAKATA Hyoe to 26 participating researchers and students as follows.

Project Associate Professor Gusyev presented a newly published ocean modeling study, which was conducted in collaboration with the Institute of Industrial Science of the University of Tokyo, to investigate anthropogenic tritium levels released from the Fukushima Daiichi Nuclear Power Plant (FDNPP) site. Using the ocean general circulation model COCO4.9, the anthropogenic tritium input was simulated due to the FDNPP accidental discharge between March 2011 and 2019 and the planned release of ALPS-treated water from August 2023 to 2050. For the climate change in COCO4.9, the highest CO2 emission of the SSP5–8.5 climate scenario was implemented for the global ocean tritium simulations extended up to the year 2099. As a result, the anthropogenic tritium discharge would have negligible impact on tritium activity concentrations in the ocean for the past and far-future climates until 2099.

For the presented study, the audience confirmed the technical details of the global ocean tritium setup such as the simulations’ input of tritium radionuclide with the half-life of 12.32 years.

Professor Takata presented on the dynamics of trace elements from rivers to estuaries in Japanese coastal areas.

After each presentation, various questions and comments were raised by IER faculty members.