【作者】 张金钊；

【导师】 曾兵；

【作者基本信息】 成都理工大学 ， 核技术及应用， 2011， 硕士

【摘要】 氡气作为一种放射性气体,在环境中很容易被人吸收,如果人体长期受到氡及其子体的电离辐射将诱发肺癌、白血病和呼吸道等疾病。氡气在空气中的运移研究是氡气测量和防护的基础理论问题。本论文以实验为基础,采用活性炭累积测氡方法,对氡气在不同气体压强下的运移规律进行研究,并建立氡气在空气中的一维、三维运移方程。以下为设计的三组对比实验,用以探索氡气在空气中运移的内在规律:1.通过相同的累积时间、温度、湿度、不同的压强,分别在真空度为-0.06MPa、真空度为-0.05MPa、真空度为-0.04MPa、常压下测量了氡气在竖直密闭玻璃管内的分布。2.通过相同的压强、湿度、温度、不同的累积时间,在真空度为-0.06MPa下测量氡气在竖直、水平密闭玻璃管内的浓度分布。3.利用氡气在空气中的运移方程与氡气在不同气体压强下的浓度分布,估算出氡气在不同压强情况下的平均速度。通过实验得出以下结论:氡气在空气中运移速度与空气压强有关,空气压强越大,运移速度越快,在低压状态下向下运移更加明显;对比氡气在竖直方向和水平方向上测量结果,不管压强高低氡气运移在竖直方向上的运移能力远远超过水平方向;在不同压强情况下氡气平均速度估算结果:常压下向上运移平均速度为1.02 10^-6m/s、向下运移平均速度为2.08 10^-6m/s,低压下（相对真空度为-0.06MPa）时氡气的向上运移平均速度为0.91 10^-6m/s、向下运移平均速度为2.77 10^-6m/s,与实际测量结果符合性良好。更多还原

【Abstract】 Radon, as one kind of radioactive gas in environment, can easily be absorbed by human body. If the human body has long been ionizing radiation exposure to the radon and its daughter, it will induce lung cancer, leukemia and respiratory and other diseases. The migration study of Radon in the air is the foundation theory problems of radon measurement and protection. Basing on experiment, this thesis uses the method of active carbon accumulated measuring radon to study the migration regularity of radon gas in different gas pressure, and establish one-dimensional, 3-d migration equations of the radon in the air.The three groups of comparative experiments are as following to explore the inherent migration law of radon in the air:1.The paper measures the concentration distributions of radon in airtight vertical glass tube under the same cumulative time, temperature, humidity and different pressure in vacuum （respectively for -0.06MPa, -0.05MPa, -0.04MPa, atmospheric conditions）.2.The paper measures the concentration distributions of radon in airtight horizontal、vertical glass tube under the same pressure（for -0.06MPa vacuum）, temperature, humidity and different cumulative times.3.Basing on the migration equations of radon gas in the air and the concentration distribution of radon under different gas pressure, the paper estimates the average speed of radon gas under different pressures.Through series experiments, following conclusions can be obtained: the migration velocity of radon in the air is related with the air pressure: with greater air pressure, the conveyance speed is faster. Especially at low-pressure state the downward migration is more apparent. Through the comparison of measurement results of radon in vertical direction and a horizontal direction, the migration ability of radon in the vertical height is far larger than that in the horizontal direction whatever the pressure is. The average speed of radon in different pressures cases are estimated as follows: the upward migration average speed under atmospheric environment is 1.02×10^-6m/s, the downward migration average speed is 2.08×10^-6m/s; The upward migration average speed under -0.06MPa vacuum environment is 0.91×10^-6m/s, the downward migration average speed is 2.77×10^-6m/s. As is consistent with the practical measurement result.更多还原