Research On Radon Exhalation Mechanism And Control Of Building Materials

Radon and its progeny exposure to humans account for 50%of the total natural radiation dose.At the same time,radon and its progeny are listed by the World Health Organization?WHO?as major environmental carcinogens.With the rapid development of China's economy and society and the improvement of people's living standards,indoor radon pollution caused by building materials and building interior decoration and decoration has gradually attracted people's attention.In this paper,through the combination of experimental measurement and system simulation,the related research on the decontamination and pollution control of indoor building materials was carried out.?1?This article first studies the influence of the difference between the core temperature of the building material and the ambient temperature?0-20°C?and the internal moisture content of the building material?0-15%?on the cumulative activity concentration of radon in cement bricks under single factor conditions.On this basis,The variation rule of radon precipitation in the experimental group under single factor conditions?temperature difference:0²0?,internal moisture content of the test block 0¹5%?was analyzed,and a function between the single factor variable and the corresponding radon precipitation rate was obtained The relationship between the two factors?temperature difference,water content?was obtained under the combined action of the radon precipitation on the sample surface.?2?Scrape coating of cement mortar on the surface of cement bricks,the ratio of cement mortar cover layer?cement:sand=1:0.5¹:3?,thickness?15mm³0mm?and water content?0%⁹.3%?)The effect of cumulative radon activity concentration on cement bricks was analyzed,and the effect of cement mortar plaster covering layer on the radon precipitation on the surface of cement brick test blocks under different proportions,thicknesses and water contents was analyzed,and putty was applied on the basis of this.The effect of the thickness of the putty cover layer?5mm²0mm?on the precipitation of radon on the surface of the cement brick test block was studied.?3?Using Simulink system simulation method,establish a room model of 4m×3.8m×3m,for different air change rate(0.8 h^-1,3.0 h^-1,5.0h^-1,6.0 h^-1)and return air ratio?0,0.3,0.5,0.7,0.9?were simulated,and the variation rule of indoor radon activity concentration under different return air ratio conditions was obtained.And the system simulation results were verified by the experiment of air supply conditions,and the relative error did not exceed 10%.