Article ID Journal Published Year Pages File Type
8083311 Journal of Environmental Radioactivity 2013 12 Pages PDF
Abstract
To assess the migration patterns of radiocesium emitted from the Fukushima Dai-ichi Nuclear Power Plant (FDNPP), we analyzed 228Ra/226Ra ratios and 7Be concentrations and compared them with 134Cs and 137Cs concentrations in seawater samples collected within the Sea of Japan before and after the FDNPP accident (i.e., during the period 2007-2012) using low-background γ-spectrometry. The 228Ra/226Ra ratios in surface waters exhibited lateral and seasonal variations, reflecting the flow patterns of surface water. This indicates the transport patterns of the FDNPP-derived radiocesium by surface water. Cosmogenic 7Be (half-life: 53.3 d) exhibited markedly high concentrations (5-10 mBq/L) at depths shallower than 50 m, with concentrations decreasing steeply (0.2-2 mBq/L) at depths of 50-250 m. The distribution of 7Be concentrations suggests that the downward delivery of the FDNPP-derived radiocesium to below 50 m depth was negligible for a few months prior to its removal from the Sea of Japan.
Related Topics
Physical Sciences and Engineering Energy Nuclear Energy and Engineering
Authors
, , , , , , , , , , , , , ,