Experimental Study On The Migration Of Radon In Particle-stacked Emanation Medium Under Heat And Moisture Transfer

In recent years,the Chinese government's nuclear policy has been promoting the development of the uranium mining and smelting industry in the country.The problem of thorium pollution in the development and exploitation of uranium resources has also become more prominent.The external environmental factors of the uranium ore heap and uranium tailings heap will not only affect the decantation process of the surface of uranium ore and uranium tailings heap,but also affect the migration process of thorium within the uranium heap and uranium tailings heap.In this thesis,the uranium ore sand collected by the tailings yard of Hengyang 272 Factory was selected as a test sample,which was abstracted as a particle-packed porous emissive medium.Using a self-designed multi-functional test device,the temperature,air percolation velocity and humidity were studied.The influence of the internal migration and the radon exhalation rate on the surface of the sample was studied.Finally,the activity concentration distribution and the precipitation rule of the radon in the sample were obtained by the scintillation chamber method,and the related influencing factors were discussed.A series of research results have been obtained:(1)Under the experimental conditions,when the sample is in the free diffusion equilibrium state,the pore activity concentration decreases with the increase of the sample height,and the pore activity concentration tends to increase with the increase of the sample depth Smooth value;(2)When the sample is in different room temperature,the concentration of the pore activity at the same height and the surface radon exhalation rate increase with the increase of the room temperature;when the room temperature is constant,the sample surface excretion rate with the xenon lamp When the power rises,it increases;when the room temperature is constant and after 8 hours of exposure,the shallow temperature change of the sample is affected by the power of the xenon lamp.The rate of deuterium deposition on the sample surface changes with the power of the xenon lamp big;(3)At the same air permeation velocity,the concentration of pore enthalpy increases with the height of the sample;the rate of decantation on the surface of the sample increases with the increase of seepage velocity,but the rate of increase becomes smaller.At the end of the test,the surface radon exhalation rate tends to a stable value;(4)After the test column reaches a stable shower,the water content at different heights of the sample will increase with the increase of the spray intensity,but the temperature change range is small;when the spray is stable,the medium will maintain a certain spray.In the case of strength,the concentration of pore activity decreases with the increase of the height of the sample;the rate of precipitation on the surface of the sample decreases with the increase of the spray intensity,but the decreasing amplitude gradually decreases,and the rate of deuteration on the surface of the sample finally decreases.Tend to a stable value.