Open Access

A. Diacre, Thomas G. Chalaux, S. Burban, C. Gauthier, A. Hubert, A.-C. Humbert, I. Lefevre, O. Evrard

• The current dataset was compiled to investigate the temporal evolution of plutonium concentrations, isotopic ratios and radiocesium activity concentrations in flood sediment deposits collected in the Ukedo and Takase Rivers, draining a part of the Difficult-to-Return Zone, in Fukushima Prefecture, from 2013 to 2020. These radionuclides were released in large quantities during the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident that occurred in March 2011 in Northeastern Japan (Steinhauser et al., 2014). Models showed that ~ 80 % of radionuclide releases occurred over the ocean (Mathieu et al., 2018; MEXT, 2011). The radioactive plume is drained by several coastal rivers to the Pacific Ocean, and sediment-bound radionuclide transfers in these rivers are mainly controlled by the occurrence of typhoons and tropical storms (Evrard et al., 2021). The objective of the research relying on the current database is to investigate the temporal changes in Pu signatures that occurredThe current dataset was compiled to investigate the temporal evolution of plutonium concentrations, isotopic ratios and radiocesium activity concentrations in flood sediment deposits collected in the Ukedo and Takase Rivers, draining a part of the Difficult-to-Return Zone, in Fukushima Prefecture, from 2013 to 2020. These radionuclides were released in large quantities during the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident that occurred in March 2011 in Northeastern Japan (Steinhauser et al., 2014). Models showed that ~ 80 % of radionuclide releases occurred over the ocean (Mathieu et al., 2018; MEXT, 2011). The radioactive plume is drained by several coastal rivers to the Pacific Ocean, and sediment-bound radionuclide transfers in these rivers are mainly controlled by the occurrence of typhoons and tropical storms (Evrard et al., 2021). The objective of the research relying on the current database is to investigate the temporal changes in Pu signatures that occurred between 2013 and 2020 in flood sediment deposits collected in the Ukedo and the Takase Rivers, and to identify potential factors controlling these changes by the means of statistical approach. The current dataset comprises an Excel file including the variables description, and the data itself.…