氡析出率测量过程中抽气采集容器内氡运移的数值研究

Numerical Investigation of Radon Migration in the Collection Chamber in the Process of the Radon Exhalation Rate Measurement

氡及其子体是人类所受到的来自天然辐射的主要辐射照射源,近年来我国掺渣建材的广泛使用使得室内氡平均水平有所提高。建筑工程上的防护和减缓是降低室内氡的关键及低成本方法。GB50325-2010首次给出了建材氡析出率检测方法标准。其中主动抽气采集型测定建筑材料表面氡析出率步骤要求抽气采集容器的平均高度为0.5 m。论文通过数值模拟得到较高的高度有利于减少222Rn测量中220Rn的干扰,而且可以降低采气容器内的222Rn浓度,减少反扩散效应。因此222Rn的析出率可以利用低成本的仪器和简洁的计算得到。

The main radiation exposure from natural radiation sources for human are Radon and its daughters .In recent years , the widespread use of building materials mixed with slag make the average indoor radon level in -creased .The protection and mitigation on construction work are the key and low -cost method to reduce indoor radon.The average height of collection chamber is 0.5m required by the procedure of active drawing air type for measuring radon exhalation rates from building materials surface defined by GB 50325-2010 .In this paper , we find that higher height of the collection chamber can reduce the ^220 Rn interference in ^222 Rn measurements by nu-merical simulation;and also can decrease the ^222 Rn concentration in the collection chamber to reduce the effect of back-diffusion.222 Rn exhalation rate can be obtained by low -cost equipment and simple calculations .