Assessment of the dispersion of radionuclides in flowing water using a dynamic model

Abstract

A one-dimensional model has been developed which is used to calculate the concentration of radionuclides in water, suspended matter, and sediment along a river. The model is based on three coupled differential equations, corresponding to the three interacting environmental sectors, which have to be solved numerically. In the example given—a four hour release of 137 Cs into the Upper Rhine—a Runge-Kutta method was used to solve the equations. Long-term effects, such as desorption of radionuclides from sediment back into water, are investigated and areas for further development of the model are discussed. Although this dynamic model is especially suitable for short-term releases, it had to be validated using a long-term source term due to the lack of appropriate measurements. There was satisfactory agreement between the available measurements and the calculated results.