Monte Carlo method for determining radon diffusion coefficients in porous media

Highlights: • A method for determining radon diffusion coefficients is established by combining fractal theory and Monte Carlo method. • The method can reveal more mechanisms affecting radon diffusion than other empirical models. • The method has a fast convergence rate with good accuracy. -- Abstract: Radon diffusivity is a key parameter for estimating radon emanation from porous media. We have developed a Monte Carlo method for determining radon diffusion coefficients in porous media. In the proposed method, the probability model for pore diameter derived from fractal theory is used to describe the microscopic pore structure of porous media. The Monte Carlo technique is utilized to search for the pore size that satisfies the probability model for porous media. The convergence rate of the proposed is fast (∼3 min). Radon diffusion coefficients measured by the closed chamber method are used to validate the accuracy of the proposed method.