Identifying Cesium Discharge to the Ocean from Fukushima Daiichi NPP through Leaked Tritium Analysis

Yuichi Onda; Hikaru Sato; Daisuke Tsumune; Katsuhiko Kohata; Tomomi Okamura

Presentation information

[J] Oral

M (Multidisciplinary and Interdisciplinary) » M-AG Applied Geosciences

[M-AG34] Radioisotope migration: New Development of Environmental Dynamics Research on the 1FNPS Accident

Fri. May 31, 2024 10:45 AM - 12:00 PM 303 (International Conference Hall, Makuhari Messe)

convener:Daisuke Tsumune(University of Tsukuba), Yoshio Takahashi(Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo), Akira Kirishima(Tohoku University), Hiroaki Kato(Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba), Chairperson:Daisuke Tsumune(University of Tsukuba), Yoshio Takahashi(Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo), Akira Kirishima(Tohoku University), Hiroaki Kato(Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba)

11:15 AM - 11:30 AM

[MAG34-03] Identifying Cesium Discharge to the Ocean from Fukushima Daiichi NPP through Leaked Tritium Analysis

★Invited Papers

*Yuichi Onda¹, Hikaru Sato¹, Daisuke Tsumune¹, Katsuhiko Kohata², Tomomi Okamura² (1.Center for Research on Radiation, Isotopes and Earth System Sciences, 2.Tokyo Electric Power Company Holdings)

Keywords:Cs-137, Fukushima Daiichi Nuclear Power Plant, Tritium

Mitigating radionuclide dispersal is crucial for the decommissioning of nuclear sites and recovery post-disaster. At Fukushima Daiichi, a seawall installation led to a diminished maritime dispersal of 137Cs, though periodic releases persisted without clear causality. Contaminated groundwater, post-cleansing via ALPS and storage, showed traces of 3H post-leakage in 2013 and 2014. This study utilizes a hydrologic tracer methodology, analyzing 2015-2021 data on 3H and 137Cs in groundwater and drainage pathways at FDNPP. The analysis of leaked 3H enabled the discernment of surface flow contributions and elucidation of 137Cs sources and periodicity factors within the drainage systems. 3H-marked surface flow, bifurcated via effective rainfall methods, pinpointed high 137Cs concentrations emanating from structures, implicating them as primary 137Cs contributors. Influences of temperature and precipitation on 137Cs concentrations in basal and surface flows were observed, enhancing decommissioning efforts and suggesting the potential of 3H tracing for identifying land-to-sea pollution pathways in similar locales.