A dynamic box model to predict the radionuclide behaviour in rivers for medium and long-term periods

Abstract

Abstract. This paper presents a dynamic box model for the radionuclide behaviour in rivers on medium-and long-term periods (several days to several years). The river is described as a succession of boxes representative of its different reaches. In each reach, the compartments are the water column and three bottom sediment layers. Called interface, the first layer plays a fundamental role for the vertical exchanges of solid radionuclide phases between the water column and the sediment. The second layer results from the consolidation of the previous one. Its interstitial water is mobile and the dissolved radionuclide phases can be exchanged with the water column. It is called active. The last layer results from the consolidation of the active layer. Its interstitial water is slightly mobile and it is assumed that its dissolved radionuclide phases cannot be exchanged. It is called passive. In each compartment, the model computes the temporal evolution of the radionuclide activities in the main abiotic and biotic components. The abiotic components are the water and different matter classes classified according to their deposit kinetics. The biotic components are phytoplankton, zooplankton, and fish distributed in planktonivorous and omnivorous species, in water column and macrobenthos in bottom sediment.

Erosion threshold of saturated natural cohesive sediments: Modeling and experiments

“…[3] It has been shown that assessing the sediment flux could provide a basis for evaluating the eroded flux of pollutants [Boyer et al, 2005]. The erosion flux E (kg m À2 s À1 ) is quantified by threshold laws [Partheniades, 1965;Winterwerp and van Kesteren, 2004], which involve the ratio between the bed shear stress t (N m À2 ) of the flow and the critical erosion shear stress of the eroded surface t ce (N m À2 ).…”

Transfer modelling and toxicity evaluation of the effluent from an installation of cleansing and uranium recovery using a battery of bioassays

“…To this end, modelling was performed with the CASTEAUR code that evaluates, according to space and time, the radionuclide concentrations in the main abiotic and biotic compartments of a river (Boyer et al 2005;Duchesne et al 2003). For this study, three modules of the code were used: -The hydrographical module represents the geometry of the river as a succession of reaches, each described by its length, slope, roughness and trapezoidal section.…”

Assessment, validation and intercomparison of operational models for predicting tritium migration from routine discharges of nuclear power plants: the case of Loire River

“…The code Casteaur v0.1 (Boyer et al, 2005;Boyer and Beaugelin-Seiller, 2002;Beaugelin-Seiller et al, 2002;Duchesne et al, 2003) is dedicated to operational assessments of the radionuclides transfers in rivers. It is based on five modelling layers: a hydrographical model, a hydraulic model, a sedimentary model, a trophic chain model and a radioecological model.…”