Integrated radiation air dose rate maps over the 80 km radius of the Fukushima Daiichi Nuclear Power Plant and the entire Fukushima Prefecture during 2011-2022.

In this study, we created integrated radiation air dose rate maps in the Fukushima region during 2011-2022 using airborne, car-borne, and walk surveys and fixed-location measurements. We applied a Bayesian geostatistical method to the 80 km radius of the Fukushima Daiichi Nuclear Power Plant and the entire Fukushima Prefecture while considering the history of the evacuation zone lifting in Fukushima. The integrated maps in this study fixed the bias to underestimate the air dose rates in forest areas and created integrated maps with a wider area and time series than previous studies.

Simulation study on H behavior in the Fukushima coastal region: Comparison of influences of discharges from the Fukushima Daiichi and rivers.

The release of tritium (H) to the ocean is planned on the coastal environment in the Fukushima coastal region from Spring or Summer of 2023. Before its release, we evaluate the effect of H discharges from the port of Fukushima Daiichi and rivers in the Fukushima coastal region using a three-dimensional hydrodynamic model (3D-Sea-SPEC). The simulation results showed that discharges from the port of Fukushima Daiichi dominantly affected the H concentrations in monitoring points within approximately 1 km.

A modeling approach to estimate H discharge from rivers: Comparison of discharge from the Fukushima Dai-ichi and inventory in seawater in the Fukushima coastal region.

Estimation of H discharge from river catchments is important to evaluate the effect of Fukushima Dai-ichi discharge and future planned H release to the ocean on the coastal environment. Using a previously developed model based on the tank model and observed H concentration in river water, the H discharge from the Abukuma River and 13 other rivers in the Fukushima coastal region were estimated from June 2013 to March 2020. The H discharge from catchments of the Abukuma River and 13 other rivers in the Fukushima coastal region during 2014-2019 were estimated to be 1.

Dynamics of radiocaesium within forests in Fukushima-results and analysis of a model inter-comparison.

Forests cover approximately 70% of the area contaminated by the Fukushima Daiichi Nuclear Power Plant accident in 2011. Following this severe contamination event, radiocaesium (Cs) is anticipated to circulate within these forest ecosystems for several decades. Since the accident, a number of models have been constructed to evaluate the past and future dynamics of Cs in these forests.

Vertical and horizontal distributions of Cs on paved surfaces affected by the Fukushima Dai-ichi Nuclear Power Plant accident.

Vertical and horizontal distributions are fundamental for sampling and in-situ gamma spectrum measurement strategies. The distributions of Cs were investigated for paved surfaces affected by the Fukusima Dai-ichi Nuclear Power Plant accident. Additionally, the effects of the distributions on the measurement uncertainties of in-situ spectrometry were evaluated.