Modelling the long term dispersion of radioactive liquid effluent and dose from marine pathways using a grid model

A grid model was developed to combine small-scale grid resolution and long-term predictions of radionuclide dispersion in shallow seas. A predictor-corrector algorithm ensures an unconditional stability of the model. Four modules calculate the concentration of suspended sediments, the dispersion of radionuclides in the marine environment, and the doses to members of the public and marine biota. The model was applied to the dispersion of liquid effluent in the Irish Sea from the Sellafield nuclear reprocessing plant, Cumbria (UK). The concentration factors and partition coefficients have been calibrated for biota species and local conditions. The validation against environmental samples for twenty-two radionuclides shows a good agreement between predicted and measured values.