某铀矿10年监测资料分析和井下氡及其子体浓度的分布

目的了解某铀矿井下氡及其子体在10年间不同年份、不同季节、不同场所的分布规律,以便有针对性地采取井下降氡措施。方法收集1995~2004年间某铀矿井下氡及其子体浓度资料,计算平衡当量氡浓度及平衡因子F。结果主要工作面(一类)的氡及其子体浓度均高于辅助工作面(二类)(P<0.01),未通风时的氡浓度明显高于通风时的浓度(P<0.01)。铀矿井下氡及其子体浓度在夏季、秋季比春季、冬季高,5月和9月的水平接近年平均水平。在出碴、出矿、打钻和支柱等主要作业面的作业点处氡及其子体浓度较高。导出铀矿井下空气中年平均氡浓度为2 977 Bq/m3,测定样品中超过年平均浓度的占26%,平均平衡因子F=0.34。结论通风是降低井下氡及其子体浓度主要的有效方法。5月和9月是调查铀矿井下氡及其子体平均辐射水平可考虑的最佳季节。

Analysis on Monitoring Data in 10 Years and Concentration Distribution of Radon and Its Daughters in Uranium Mine

Objective To analyze the variations of radon and its daughters' concentrations in ten years in a uranium mine in order to implement relevant measures to lower the concentration.Methods The monitoring data of radon and its daughters from 1995 to 2004 were collected to calculate its equilibrium equivalent concentration(C_(eq))and its equilibrium factor.Results Radon and its daughters' concentrations in the air of the main workplaces were higher than those of the auxiliary workplaces(P<0.01).Concentrations under ventilation were lower than those without ventilation(P<0.01).Concentrations in autumn and summer were higher than those in spring and winter.Concentrations in May and September approximated with the yearly average.Those in the job categories such as mining,drilling,and supporting were higher than in others.The yearly average radon concentration was 2977 Bq/m~3,with 26 percent of the total samples exceeding the average.The equilibrium factor was calculated as 0.34.Conclusions Ventilation is an effective way to lower the radon and its daughters concentration.May and September may be taken as the optional months for investigating the average level of the mine.