Testing a model of Cs¹³⁷ movement in a catchment-lake system. Problems found in parameter identification and uncertainty assessment

Summary

A comprehensive Catchment-Lake model has been developed to evaluate the transfer to several lake subsystems of airbone Cs¹³⁷. The model has been built using standard radiological protection techniques and has been applied to Esthwaite Water (UK), comparing the simulated results with experimental values. This research has been carried out in the frame of IAEA Validation of Model Predictions (VAMP) exercise. This paper summarises the conceptual and quantitative problems encountered in evaluating the sources of uncertainity in the final result. The most uncertain parameters are related to the drainage processes. Even though it does not have a large effect on the evaluation of the integrated concentrations in the lake, it can produce large misper-formance of the model in time dependent predictions, specially when very different scenarios are addressed.