16:15 〜 16:30
[MAG34-09] Estimation of radionuclide source from the Fukushima Daiichi Nuclear Power Plant using 3H/137Cs ratio
キーワード：Radionuclide dispersion, Fukushima Daiichi Nuclear Power Plant Accident, H-3/Cs-137 ratio, Groundwater
Thirteen years have passed since the accident at the Fukushima Daiichi Nuclear Power Plant, but the levels of 137Cs and 3H near the power plant have not returned to the levels they were at before the accident. In addition, the levels of 137Cs and 3H near the power plant continue to be higher than in other areas of the sea. This suggests a persistent leakage from the power plant or the surrounding sea area. However, the mechanism of the leakage is unknown. As the estimated rate of leakage outside the port is higher than the estimated rate of leakage inside the port, it is also possible that the leakage is not via the port.
The ratio of radioactive material concentration does not change in seawater over a short period of time, so it is useful for estimating the source of leakage. Here, we focused on the ratio of 3H and 137Cs and analyzed the data.
After 2016, the concentration of 137Cs near the power plant has hardly decreased.
The concentration of 137Cs and 3H is high in the port area and low outside the port area. However, the 3H/137Cs ratio is small in the port area and large outside the port area. This suggests that the concentration of137Cs and 3H in the port area does not necessarily affect the concentration outside the port area, and there is a possibility that there is another source.
The 3H/137Cs ratio exhibits significant spatial and temporal variations. This could be attributed to the presence of multiple sources with varying 3H/137Cs ratios, or it might be a sampling issue caused by substantial fluctuations in concentration over time and space.
We have now started analyzing the 3H/137Cs ratio in nearby river water and groundwater and will discuss the relationship between these at the time of the presentation.
The ratio of radioactive material concentration does not change in seawater over a short period of time, so it is useful for estimating the source of leakage. Here, we focused on the ratio of 3H and 137Cs and analyzed the data.
After 2016, the concentration of 137Cs near the power plant has hardly decreased.
The concentration of 137Cs and 3H is high in the port area and low outside the port area. However, the 3H/137Cs ratio is small in the port area and large outside the port area. This suggests that the concentration of137Cs and 3H in the port area does not necessarily affect the concentration outside the port area, and there is a possibility that there is another source.
The 3H/137Cs ratio exhibits significant spatial and temporal variations. This could be attributed to the presence of multiple sources with varying 3H/137Cs ratios, or it might be a sampling issue caused by substantial fluctuations in concentration over time and space.
We have now started analyzing the 3H/137Cs ratio in nearby river water and groundwater and will discuss the relationship between these at the time of the presentation.