A process-based model for the partitioning of soluble, suspended particulate and bed sediment fractions of plutonium and caesium in the eastern Irish Sea

The model predicts that sediment reworking and transport are the key environmental processes as the Sellafield Pu(α) and 137Cs discharge continues to decline. Inventory calculations generated by the model are consistent with previous estimations. For a hypothetical post-discharge scenario, the concentrations of these radionuclides in both seawater and surface sediments are predicted to decrease sharply, concurrent with a downward vertical migration of the activity retained in sediments.