Study On Radon Transport Regularity In Finite-thickness Crushing Emanation Medium And Its Application

The personal dose level of uranium mine workers of our country is3to5times higher than theworld average level, and it is undoubted that such a high personal dose will restrict the sustainabledevelopment of uranium mining industry of our country. While crushing emanation media such asuranium ore heap existing extensively in uranium mine are the main source of radon and its progenies,the study of radon transport and its exhalation law in uranium ore heap is rare up to now. Therefore, tostudy the radon transport and its exhalation law in uranium ore heap is of significant practical sense andapplication value for the radon protection design of uranium mines, and it will also provide theoreticalinference for radon transport in various geological environments.Supported financially by the national natural fund project (project number:11105069), this paperabstracted the uranium ore heap as a finite-thickness crushing emanation medium.. Firstly, the radontransport and exhalation mechanisms in the crushing emanation medium were analyzed. Then, theuranium ores of particle size+4mm-5mm from certain uranium mine were chose as the experimentalsample. The diffusion coefficient and the free radon production rate of the crushing emanation mediumwere obtained using the self-made multifunctional experimental apparatus simulating the radondiffusion-flow transport. And the effect of air flow velocity on the radon transport in the crushedemanation medium and the radon exhalation rate on the medium’s surface was studied. finally, thenumerical simulation of the radon transport in the blind roadway of certain uranium mine wasconducted by the Fluent, obtaining the radon concentration distribution and exhalation law of theuranium ore heap in the blind roadway. Afterwards the relative influence factors were analyzed.The outcomes of this study are as follows:1. A multifunctional experimental apparatus simulating the radon diffusion-flow transport in thefinite-thickness crushing emanation medium was designed and made.2. The experiment of radon diffusion in the finite-thickness crushing emanation medium wasconducted using the self-made experimental apparatus, studying the radon diffusion transport law in thecrushing emanation medium. This provides a simple and effective method for obtaining the diffusioncoefficient and the free radon production rate.3. The experiment of radon flow in the finite-thickness crushing emanation medium was conductedusing the self-made experimental apparatus, studying the radon transport in the crushed emanationmedium and the variation law of the radon exhalation rate on the medium’s surface under different flow velocities. As the experimental results showed, when the gas permeability in the crushing emanationmedium is quite large, the internal radon transport is prone to be governed by the flow. Within a certainflow velocity range, the radon concentration at the same height with the flow velocity increasingdecreased in the negative exponent way, and the radon concentration under the same flow velocity withthe medium height increasing increased linearly. Moreover, the radon exhalation rate on the medium’ssurface increased exponentially with the flow velocity increasing.4. The numerical simulation of the radon transport in the blind roadway of certain uranium mine wasconducted by the Fluent, obtaining the radon concentration distribution and exhalation law of theuranium ore heap. This provides a significant inference for the selection of ventilation pattern and theventilation design of the blind roadway.