铀矿山排风井氡排放率连续测量方法的研究

发布时间：2018-01-18 01:03

本文关键词：铀矿山排风井氡排放率连续测量方法的研究　出处：《南华大学》2016年硕士论文　论文类型：学位论文

【摘要】：随着核工业发展的备受重视,我国对于铀矿资源开采正在逐年向更快,更深方向发展。据研究表明,铀矿冶系统对公众产生的集体剂量中,气态放射性流出物造成的集体辐射剂量占76.6%,且井下作业的工作人员所受辐射危害,85%是来自铀矿通风风流中的氡及其子体对人体造成的内照射。GB23726—2009《铀矿冶辐射环境监测规定》和GB23727—2009《铀矿冶辐射防护和环境保护规定》等国家标准,都提到排风井氡浓度及排放率是矿山放射性气态流出物监测项目之一,但目前对于铀矿冶气态流出物的排放限值国内标准中并没有相关规定。排风井氡排放浓度是具有一定分布规律的,但实际工作中仅简单从排风井口选取一点进行取样测量氡浓度以及风速,从而估算出来的氡排放率会有很大误差。因此急需对铀矿排风井的氡浓度分布规律进行研究,并据此建立一种快速准确测量氡排放率的方法。采用单点采样法测量研究了我国某铀矿排风井排放口的氡浓度以及风速分布,并用插值积分程序计算排氡率,研究结果发现,铀矿排风井井口2m深度断面上的氡浓度及风速径向分布均呈近似轴对称的抛物线状分布,即中心最高,从中心往两边,距离井壁越近,氡浓度和风速都越低。在此研究基础上设计了一种便于无人值守监测的混合平均测量氡浓度法。在结束单点采样测量后,应用混合平均测氡方法进行了对同一铀矿通风口进行了约12小时的连续监测,实验结果表明,混合平均测氡法刚开始测量的一段时间内,氡浓度测量结果较稳定,该方法测量出来的平均氡浓度约为6.36×104Bq/m3,计算出来的氡排放率为7.414×106Bq/s,而单点采样计算出来的平均氡浓度约为6.35×104Bq/m3,计算出来的氡排放率为7.419×106Bq/s,两种方法得平均氡浓度测量结果相对偏差在0.1%以下,二者最终结果非常接近,这印证了混合平均测氡法的有效性。由此可以看出单点采样法能够较准确的测量铀矿排风井的氡浓度分布情况,而混合平均测量氡浓度法适合对排风井的平均氡浓度测量,该方法既保证了测量的准确性,又能够节约大量的人力物力,因此混合平均法是发展铀矿排风井氡排放率连续监测的重要手段。此研究工作为今后实现矿山排风井氡排放率的连续准确监测奠定了基础。
[Abstract]:With the development of nuclear industry has been paid more attention in China for the exploitation of uranium resources is gradually to faster and deeper direction. According to the study, the collective dose from uranium mining and metallurgy system for the public to produce in the collective radiation dose caused by radioactive gaseous effluents accounted for 76.6%, and the downhole operations staff radiation hazards, 85% from radon ventilation in uranium ore body on the human body caused by the irradiation of.GB23726 radiation monitoring provisions on the environment of 2009< and GB23727 - 2009< uranium mining and metallurgy of uranium mining and metallurgy in radiation protection and Environmental Protection Regulations > and other national standards, mentioned the exhaust shaft radon concentration and emission rate is one of the mine radioactive gaseous effluent monitoring project, but for uranium the mining of gaseous effluent discharge limits of domestic standards and no relevant provisions. The emission concentration of radon exhaust outlet is a certain distribution, but in practice only Jane The single row is selected from a wind wellhead sampling and measuring radon concentration and wind speed, and the estimation of radon emission rate will have a great error. So it is necessary to uranium mine Radon concentration distribution were studied, and established a rapid and accurate method for measuring radon emission rate. The radon concentration and velocity distribution of a uranium mine exhaust shaft with discharge of single point measurement method, and exhaust radon rate interpolation integral calculation, the results of the study showed that radon concentration and velocity of radial distribution of uranium mine wellhead 2m depth section showed approximate axis of the parabola, i.e. high center and from the center to both sides. The wall distance closer, radon concentration and wind speed are lower. Based on the study of a design for unmanned monitoring and mixed average radon concentration measurement method. At the end of the single point sampling survey, the average mixed application Radon measurement methods are of the same uranium were continuously monitored vents for about 12 hours, the experimental results show that the mixed average radon method at the beginning of the measurement for a period of time, the concentration of radon measurement results are stable, the average radon concentration measurements from about 6.36 * 104Bq/m3, calculated the rate of radon emission 7.414 * 106Bq/s, the average radon concentration and single point sampling calculated about 6.35 * 104Bq/m3, radon emissions calculated rate of 7.419 * 106Bq/s, the two methods have the average radon concentration measurement results of the relative deviation below 0.1%, two final results are very similar, which confirms the validity of the hybrid average radon method. It can be seen that the radon concentration distribution of single point sampling method can accurately measure the uranium mine, and mixed average radon measurement method is suitable for the average radon concentration measurement method of the exhaust outlet, it can ensure the measurement The accuracy, but also save a lot of manpower and resources, so the mixed average method is an important means to develop uranium mine radon emission rate of continuous monitoring. Laid the foundation for the research work of continuous accurate monitoring of radon emission rate of exhaust outlet for the future of the mine.

【学位授予单位】：南华大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TL751

【相似文献】