Spreading of the radioactive leakage from Fukushima nuclear plant in Japan

The extraordinary earthquake that generated an extreme tsunami that struck Japan, has led to radioactive leaks into the sea from the Japanese Fukushima reactors. Dr. Yongqi Gao and Prof. Ola M. Johannessen at the Mohn Sverdrup Center at the Nansen Environmental and Remote Sensing Center in Bergen, Norway and Nansen-Zhu International Research Center (NZC, Beijing, China), used a numerical model to simulate the potential spread of radioactive waste into the sea from Fukushima reactors and among other things the spreading towards China. This modelling system has been developed over the past ten years and has previously been used for the modeling of radioactive dispersal from Sellafield in the UK and from sources in the Russian Arctic sector both at present and in the future under different scenarios, supported by the Norwegian Research Council, the EU and with contributions from Trond Mohn c / o Frank Mohn AS.

With the simulation from Fukushima reactors, we assume a constant leak throughout one year from March 2011. Even with only one month of leakage the spreading patterns will in principle be the same, but over a smaller area. The results show that the maximum concentration propagates eastward in the Pacific toward the United States during a 7-year period while the total concentration drops to 1-2% of the source concentration (100%) after 5 years. (see figure and the animation at the below link).

It should be mentioned that a more scientific assessment of the potential threat to the marine environment requires real values of the radioactive leak and the fallout from the atmosphere, which we do not yet have at present.

Figure caption: The figure shows a hypothetical simulated dispersal pattern of a radioactive leak from Fukushima reactors that lasts for one year from March 2011. As time passes and the spread covers a larger area, the concentration of the radioactive substances decrease to approx. 2% after 5 years. 2011 (a), 2012 (b), 2013 (c), 2014 (d), 2015 (e), 2016 (f), 2017 (g) og 2018 (h).

Norwegian TV2 news report; Ocean spreading of radioactivity from the Fukushima nuclear power plant.

The Nansen Center has made model simulations of potential oceanic spreading of radioactivity in from the Fukushima nuclear power plant in Japan. The simulations indicate a seven years time to cross the Pacific Ocean to the US coast.

For further information contact:
Ola M. Johannessen (ola.johannessen@nersc.no) Mobil: 901 35 336.