Development And Implementation Of A Computer Code For Modelling The Dispersion Of Radioactive Pollutants Around Dumping Sites

A 3D mathematical model LMT3D has been developed and adapted to simulate the transport and dispersion of radioactive (RA) pollutants around dumping sites. The model consists of two coupled sub-models:hydrodynmic sub-model and mass-transport submodel. The hydrodynamic sub-model is 3D, non-linear and baroclinic. A finite hybrid numerical scheme is used in a orthogonal grid to solve the basic equations. The mass-transport sub-model solves the advection-diffusion equation by a lagrangian-based particle tracking method. Several forcing factors can be occounted for in both sub-models: wind forcing,thermo-haline forcing, inflow of rivers or inflow/outflow through straits. The integrated model was applied to carry out a detailed study of transport-dispersion of RA pollutants in the Japan Sea. The report presents a description of the problem, the model and the results. A large amount of radioactive (RA) waste has been deposited in the Japan Sea at the sea bottom, at a depth of about 3500 meters. Although several measurements of RA pollution in this sea have shown no increase of radioactivity over the natural values, concern exists that there may be some leakage of the RA pollutants from the dumped waste. The question is where they might be transported by currents and dispersion, and especially after what time and where they would reach the surface layers, where they might contaminate fish and other marine organisms.