Modelling the Sea-to-Land Transfer of Marine Discharges from Sellafield — Validation Against Environmental Measurements

Abstract

Radionuclides discharged into the sea may return to land in the marine aerosol. The extent and significance of this transfer around Sellafield has been assessed using a series of computer models.

A marine model calculates the dispersion of radioactivity through the Eastern Irish Sea. Validation of the model is by comparison against the observed distributions of ²⁴¹Am. Transfer of radionuclides to the land is empirically modelled using measured deposition. This simple model reproduces both current and cumulative deposition well. Validation of airborne activity against time series data is less good.

The maximum dose to the average person in Seascale due to the transfer of actinides was calculated to be 24 μSv in 1973, which will reduce to 2 μSv in 2000. However, use of site-specific data may change these predictions.