Software Package of Atmospheric Radionuclide Distribution Models and Its Use for Assessing the Radiation Conditions after the Fukushima Dai-ichi Nuclear Power Plant Accident

K. G. Rubinshtein, E. M. Nabokova, R. Yu. Ignatov, M. M. Smirnova, R. V. Arutyunyan, V. N. Semenov, O. S. Sorokovikova, A. V. Fokin, D. A. Pripachkin, and D. V. Dzama

Described is the process of trial, adjustment, and development of the joint complex of models consisting of the WRF-ARW (Weather Research and Forecasting) regional hydrodynamic model (the United States) and radionuclide transport model from the NOSTRADAMUS package. Using these models, the computation is carried out of the fallout and radiation dose rate on the territory of Japan after the Fukushima nuclear power plant accident. To adjust the hydrodynamic model, its results were preliminarily compared with the data of observations at the mast and the assessment of the model complex was based on the data of atmospheric tracer concentration measurements during the in situ experiments carried out in 1983–1985 near Karlsruhe (Germany). Described is the version of hydrodynamic prognostic model and radionuclide transport model prepared for the present paper. Given are the results of the statistical analysis of different numerical experiments of the model complex and the results of the simulation of radiation conditions on the territory of Japan after the Fukushima Dai-ichi nuclear power plant accident. It is demonstrated that the errors in the vertical distribution of the model wind are extremely sensitive to the type of parameterization of surface and boundary layers in the model. The comparison of computed and measured values demonstrated their satisfactory coincidence.