| Autor: |
Nielson, K. K., Rogers, V. C., Gee, G. W. |
| Zdroj: |
Soil Science Society of America Journal; May 1984, Vol. 48 Issue: 3 p482-487, 6p |
| Abstrakt: |
A mathematical model was developed for calculating radon diffusion coefficients from water contents and pore size distributions of soil materials. The model accounts for radon diffusion in the air‐filled and the water‐filled pore space, for radon solubility in water, and for Knudsen diffusion in extremely small air‐filled spaces. The model considers soil pores to be composed of all possible serial combinations of the size increments from a measured pore size distribution. Diffusion coefficients for the resulting composite pores are computed and then used to calculate the overall diffusion coefficient of the soil by assuming parallel diffusion through all of the pore combinations. The resulting diffusion coefficients increase with the median pore diameter, and decrease with increasing soil water contents and with increasing widths of the soil pore size distribution. The model diffusion coefficients compare well with measured coefficients and with empirical calculations and are useful in evaluating the required soil cover thickness for uranium mill tailings reclamation. |
| Databáze: |
Supplemental Index |
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