A simple model to simulate the diffusion pattern of radon in different soil media

Abstract

Radon is transported through soil matrix and is exhaled at soil-atmosphere interface. The exhalation rate from soil is largely governed by the concentration gradient and the pressure differences. Study of the transport phenomenon aids in evaluating the radon exhalation rate of the source matrix. The present study deals with numerically solving the well established one-dimensional radon transport model and simulates the radon propagation till the attainment of steady state. The modeling was done by adopting the finite difference method. The effect of advection phenomenon coupled along with diffusion was studied. The limitation of the explicit scheme was overcome by employing the implicit scheme. The model developed was fed with experimentally derived input parameters. The radon depth profile thus obtained was compared with the experimental values. The model was used to investigate how the radon concentration profile evolves with time, for two different diffusion coefficients.