Min, B.-I.; Suh, K.-S., and Park, K., 2017. Analysis of continuing cesium release to the sea from the Fukushima Dai-ichi nuclear power plant until 2013. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 80–84. Coconut Creek (Florida), ISSN 0749-0208.

A two year time-series of ¹³⁷Cs concentration is presented from the ocean surface observed at sites 20 km radius from Fukushima Daiichi Nuclear Power Plant (FDNPP). The data used in this study were publicly released by the Tokyo Electric Power Company (TEPCO) and are available on websites of TEPCO. Publicly released data on ¹³⁷Cs radioactivity in seawater near the power plant strongly suggest a continuing release of radionuclides to the sea. The ¹³⁷Cs radioactivity in the harbour water was substantially higher than that of seawater outside and remained relatively stable after June 2011. The consistent gradient of radioactivity between observed results at outer sea sites a 20 km radius from FDNPP indicates that radionuclides are still being released continuously from somewhere in the vicinity of the reactor housings. The relatively stable ¹³⁷Cs radioactivity of the harbour water cannot be explained without a continuous input of radioactivity into the harbour. Assuming a steady state, there is a continuous input to the harbour and hence a continuous release to the outer sea.