Experimental study of radon migration parameters in uranium tailings under frozen and non-frozen conditions

Abstract

To investigate the relationship between the radon diffusion coefficient and free-radon production rate with ambient temperature and water saturation of uranium tailings under frozen and non-frozen conditions, a method was proposed to simultaneously determine the free-radon production rate as well as the diffusion coefficient in porous emanation media based on the pure diffusion migration theory of radon. The diffusion coefficient (α), the free-radon production rate (D), and gas permeability (K) of radon at different temperatures (20 °C, 0 °C, − 10 °C and − 20 °C) and water content saturation (m = 0 and m = 0.52) were determined by a self-made experiment device. The results showed that: (1) the free-radon production rate and the diffusion coefficient of uranium tailings increased with the increase of temperature in the range of 0.77–4.80 Bq·m⁻³·s⁻¹ and 1.56 × 10^–6–3.27 × 10^–6 m²·s⁻¹, respectively, when the temperature was in the range of − 20 to 20 °C. (2) With the increase of temperature, the free-radon production rate of dry uranium tailings and uranium tailings with a water saturation of 0.52 increased linearly, and the diffusion coefficient increased nonlinearly; (3) the permeability of uranium tailings with a water saturation of 0.52 at the same temperature was less than that of dry uranium tailing, and the former increased with increasing temperature, while the latter was the opposite. The methods and data obtained in this study can provide references for further research in this field, and the relevant results can be used to evaluate the potential environmental effects of radon migration parameters in uranium tailings ponds under different seasonal temperatures and water saturation conditions.