A New comparison of marine dispersion model performances for Fukushima Dai-ichi releases in the frame of IAEA MODARIA program

Periez, R.*; Brovchenko, I.*; Duffa, C.*; Jung, K.-T.*; Kobayashi, Takuya ; Lamego, F.*; Maderich, V.*; Min, B.-I.*; Nies, H.*; Osvath, I.*; Psaltaki, M.*; Suh, K.-S.*

A detailed intercomparison of marine dispersion models applied to the releases from Fukushima Dai-ichi Nuclear Power Plant has been carried out in the frame of MODARIA program, of the IAEA. Models have been compared in such a way that the reasons of the discrepancies between them can be assessed. The overall idea is to harmonize models, making them run with the same forcing in a step-by-step procedure, in such a way that the main agent in producing discrepancy between models can be found. It has been found that the main reason of discrepancies between models is due to the description of the hydrodynamics. However, once this has been suppressed, some variability between model outputs remains due to intrinsic differences between models. The numerical experiments have been carried out for a perfectly conservative radionuclide and for Cs. Model outputs for this radionuclide have also been compared with measurements in water and sediments.