Distribution of Cs on components in urban area four years after the Fukushima Dai-ichi Nuclear Power Plant accident

Yoshimura, Kazuya  ; Saito, Kimiaki  ; Fujiwara, Kenso 

This study evaluated relative Cs inventory on urban surfaces to the initial inventory on plane permeable field in evacuation zone about four years after the Fukushima Dai-ichi Nuclear Power Plant accident. The average relative inventory of paved ground was 0.18, accounting for 20% of that on plane permeable ground. Other urban surfaces showed small average values less than 0.1, indicating rapid removal of radiocesium from urban surfaces. Roads, roofs and rooftops, however, showed large variations in the relative inventories, which occasionally exceeded 0.4. Difference in material was indicated to be a factor of the variation observed for roofs/rooftops. Different relative inventories were found for roads and roofs between this study and the case in Europe, suggesting the importance to evaluate regionally-specific relative inventory on urban surfaces.