The Study Of Fast Measurement Method For Potential Radon Concentration In Soil

Radon and its daughters, a major source of natural radiation suffered by humanbeing, caused the dose of about50%of all natural radiation. The world average, about60.4percent of the low-rise buildings indoor radon comes from the buildingfoundation and surrounding soil. The potential radon concentration in soil(themaximum radon concentration in soil) is directly related to indoor radon levels of thelow-rise buildings, the depth of direct measurement normally takes up to severalmeters,the measurement is very difficult. There are not yet fast and reliablemeasurement methods of the potential radon concentration in soil. In china, the radonconcentrations in soil measured is the radon concentration in shallow soil, because themeasuring depth is only0.5-0.8m. So that it’s necessary to find a way to get thepotential radon concentration in soil fast.In this paper, based on analyzing the migration and distribution of radon in theinfinite homogeneous soil, we established a dual-source method theoretical modelwhich can get the potential radon concentration in soil fast by take advantage of theradon concentration in the shallow soil and the radon exhalation rate of soil surface,and verified this theoretical model by experiment in the soil jar of Shenzhen instituteof building. The experimental results show that the relative error between thepotential radon concentration value measured by the dual-source method and thevalue measured by normal method within the range of±10%, it’s proved that thepotential radon concentration in soil measured by dual-soure method is reliable.Meanwhile, we conducted a detailed analysis of the experimental datas, because ofthe soil jar can not meet the requirements of the infinite homogeneous soil, we made acompensatory correction and a repeated-iterated correction for the experimental datas,and achieved better results. On the other hand, in this paper we introduced the research about two-point method, two-point method using the distribution curve ofradon concentration in the infinite homogeneous soil, which can also be used for themeasurement of potential radon concentration in soil. We can get reliable results ofthe potential radon concentration by two-point method in the infinite homogeneoussoil, but if the measured soil does not satisfy this condition, then the two-point methodcan’t be used to measure the potential radon concentration. Meanwhile, we conducteda field application of the dual-source method, the results show that there will be alarge error during the rainfall weather conditions cause of the low radon exhalationrate. But if the weather is fine, we can get a reliable result of the potential radonconcentration in soil by take advantage of the dual-sorce method.The dual-source method reserched in this paper will make the measurement ofthe potential radon concentration in soil become convenient, it’s avoid thecomplicated work that drilling holes2to3meters deep. What’s more, the dual-sourcemethod will make the measurement of the radon concentration in soil more practicaluseful, no longer confined to the measurement of the radon concentration in theshallow soil which have low representativeness. On the other hand, the results of thispaper can provide an effective method to quickly and accurately find the radonanomaly area, and the technical support for the building site, the building design ofradon protection and developing more scientific indoor radon control procedures bynational authorities, is of great scientific significance and practical value.