Ocean Model Assures Safe Fukushima Wastewater Release

• Researchers from the University of Tokyo and Fukushima University have combined accurate estimates of tritium release with an ocean circulation model called COCO 4.9.

• The model solves the basic physics of ocean flow on a grid with 62 vertical layers and two alternative horizontal meshes.

• Tritium was injected into the model in two phases: adding 179- 181 TBq for the 2011-2019 period and 480 TBq over 2023-2051.

• Tritium levels in the open Pacific remained below current detection limits, except near the plant during the 2011 accident spike.

• The team reported that warmer oceans might shift the Kuroshio Current north and strengthen eastward flow, cutting the time the first trace of tritium takes to travel to the mid-Pacific and Asian subtropical coasts by roughly three years.

• The modelled concentration of tritium stayed three orders of magnitude under the detection threshold.

• The team’s findings will be published in the November 2025 edition of Marine Pollution Bulletin