破碎射气介质内氡渗流运移和析出规律的实验研究

渗流是破碎介质内氡运移的主要方式之一，研究氡在破碎射气介质内的渗流运移和析出规律对氡的防护设计具有重要意义。为此，本文以粒径为4～5 mm的铀矿石为实验样品，利用自制的一维渗流实验装置研究了不同渗流速度下破碎射气介质内孔隙氡活度浓度和介质表面氡析出率的变化规律。实验结果表明，破碎射气介质的气体渗透率较大，氡的运移很容易由渗流主导。当破碎射气介质内氡主要以渗流方式运移时，可通过测量介质内同一位置不同渗流速度的孔隙氡活度浓度或同一渗流速度不同位置的孔隙氡活度浓度，运用氡在射气介质中的浓度分布解析式和非线性最小二乘法，估算出介质的可运移氡产生率。一定渗流速度范围内，同一高度的氡活度浓度随渗流速度的增大呈负指数减小，同一渗流速度的氡活度浓度随离介质渗流入口距离的增大近似呈线性增大。介质渗流出口表面氡析出率随渗流速度的增大呈指数增大，最终趋于稳定。

Experimental Study on Radon Seepage Migration and Exhalation Laws in Fragmented Emanation Media

The seepage is one of the main ways of radon migration in the fragmented media, so it is of great significance to study radon seepage migration and exhalation laws in the fragmented emanation media for the design of radon protection. The uranium ore particles whose diameters were from 4 mm to 5 mm were chosen as the experimental samples, and a home-made one-dimensional seepage experimental device was used to study the variation of pore radon activity concentration in the fragmented emanation media and the variation of radon exhalation rate in the surface of fragmented emanation media at different seepage velocities. The experimental results show that the gas permeability is quite large in the fragmented emanation media, so the seepage becomes the main force of radon-migration. When the main way of radon migration is seepage, by measuring the pore radon activity concentrations under different seepage velocities at a fixed position or at different positions under a seepage velocity, the free radon production rate can be estimated according to the analytic equation of radon activity concentration distribution in the emanation media and the non-linear least square method. Within the range of certain seepage velocity, the radon activity concentration at a position decreases with negative exponent along with the seepage velocity increase, and the radon activity concentration under a seepage velocity increases approximately linearly along with the distance from the media seepage inlet. The radon exhalation rate on the surface of the media seepage outlet increases exponentially with the seepage velocity, and gets stable at last.