This paper provides an overview and information on radon migration in the crust. In the past several decades, numerous studies on radon migration have been published. However, there is no there is no comprehensive review of large-scale radon transport in the earth crust.
View Article and Find Full Text PDFEnviron Sci Pollut Res Int
April 2023
This paper develops a new two-dimensional model to estimate the radon exhalation rate of fractured porous media. The fractal discrete fracture network is used to characterize the fracture structure in the model. The finite element method solves the governing equations of radon migrations in fractures and porous matrix.
View Article and Find Full Text PDFThe temperature-dependent diffusion coefficient of radon is one of the most important parameters for predicting radon migration in porous media. In order to measure this parameter more effectively and accurately, theoretical formulas were derived by the steady-state one-dimensional equation of radon migration in porous media for designing the corresponding experimental device, which was used to measure the diffusion coefficients of radon in uranium mill tailings. The results show that the diffusion coefficient of radon in porous media increases with increasing the temperature, which is in agreement with existing researches, verifying the method effectiveness.
View Article and Find Full Text PDFA novel model is proposed to simulate radon migration by combining the fractal theory and the discrete fracture network (DFN) model. In the model, a power-law distribution based on fractal theory is applied to fracture length and aperture and the fracture locations and orientations are modeled with the Poisson distribution and von Mises-Fisher distribution, respectively. The model was applied to produce a computer code that can calculate the radon concentration, flux, and diffusivity of the fractured media.
View Article and Find Full Text PDFRadon is considered a significant contaminant that affects indoor air quality. Neutralization is one of the most important environmental factors in changing pore structure of cement-based materials that may release radon. Therefore, it is necessary to study the radon exhalation of cement-based materials impacted by neutralization, which is extremely lacking.
View Article and Find Full Text PDFEnviron Sci Pollut Res Int
September 2020
Radon is one of the main causes of environmental pollution and lung cancer. The precipitation of radon from porous media is affected by the coupling of heat and moisture, which has not been considered in the existing knowledge. We present a model for predicting radon migration in porous media.
View Article and Find Full Text PDFIn order to study the radon release behavior when heap leaching uranium ores with dilute sulfuric acid, unleached uranium ores from a uranium mine in southern China were selected as test samples. Adopting parameters from leaching processes commonly used in uranium mines, a laboratory experiment was carried out for 21 days with a one-dimensional acid heap leaching experimental column. The surface radon exhalation rate of uranium ore column was determined by static accumulation method while spraying with deionized water and dilute sulfuric acid.
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