11:00 AM - 11:15 AM
[MAG34-07] Tracer study using 3H in groundwater by post-accident applied to runoff analysis at the Fukushima Daiichi Nuclear Power Plant
Keywords:Cs-137, H-3 tracer, surface runoff, base flow, Fukushima Daiichi Nuclear Accident
The main data used in the analysis for the period 2015-2020 were obtained from the website of Tokyo Electric Power Company Holdings. The concentrations of 3H, 137Cs, and β in the drainage canal water showed that the water was a mixture of two types of water. Thus, a binary mixing model using 3H concentrations and discharge rates could be used to calculate the fractions of surface runoff and base flow. Although the concentration of 137Cs in the drainage channel tended to increase as the contribution of surface flow increased, the estimated concentration in the surface flow was found to be independent of the contribution of surface flow. In addition, the estimated concentrations in surface flow, which were several hundred Bq/L until 2016, decreased to tens of Bq/L in 2020, however, no decrease in concentrations was observed after 2017. Thus, 3H originating in the post-accident can be applied as a tracer to the runoff analysis at the site. This is expected to lead to the further development of studies on the dynamics of radionuclide concentration.