Coastal transport of river-discharged radionuclides: Impact of speciation and transformation processes in numerical model simulations.

Following a potential nuclear accident, river run-off may potentially become a significant source of radionuclide contamination to the coastal marine environment. In the present work, code for radionuclide speciation and dynamic transfer of radionuclides between the different species was implemented in a Lagrangian marine dispersion model. A case study was performed where the model system utilized ocean circulation fields at relatively high spatial (160 m × 160 m in horizontal direction) and temporal resolution (1 hour), considering a hypothetical accident scenario including river discharges of Cs to the marine environment.

The impact of tidal and mesoscale eddy advection on the long term dispersion of Tc from Sellafield.

In the present work, numerical models are used to study the fate of the Tc discharges from Sellafield with a specific focus on the role of mesoscale eddy and tidal advection on the transport and dispersion of this radionuclide. Transport estimates are made with an ocean model that resolves a large part of the ocean mesoscale eddy field and also includes tides. Equivalent estimates are also computed with another model in which these processes are either absent or parametrized.