隧道施工作业人员辐射有效剂量估算

Estimation of the effective radiation dose for tunnel construction workers

目的分析建立隧道施工作业人员所接触不同电离辐射的有效剂量。方法采用方便抽样方法,选择5条采用钻爆法施工的隧道为研究对象,通过对工作场所γ剂量率、氡浓度、放射性活度浓度监测以及现场调查,估算不同作业岗位人员的内、外照射剂量和总有效剂量。结果钻爆法施工隧道工作场所存在的放射性危害因素包括氡及其氡子体、γ射线、放射性粉尘(铀-238、镭-226、钍-232和钾-40)等。隧道施工作业人员接触电离辐射的总有效剂量平均为(6.7301±1.5411)mSv。其中,氡及其氡子体、放射性粉尘、γ辐射贡献剂量平均分别为(6.1630±1.5128)、(0.0146±0.0091)和(0.5526±0.1387)mSv;放射性粉尘、贡献剂量为氡及其氡子体的0.24%。氡及其氡子体贡献剂量分别高于放射性粉尘和γ辐射的贡献剂量(P值均<0.05)。放射性粉尘中,贡献剂量由高到低依次为钍-232、铀-238和镭-226。结论隧道施工作业人员所接触电离辐射的有效剂量中,以氡及其氡子体所致内照射剂量贡献最大,其次为γ辐射所致外照射剂量;放射性粉尘所致内照射剂量可忽略不计。

Objective To analyze and set up the effective dose of different ionizing radiation for tunnel construction workers.Methods A total of five tunnels constructed using drlling and blasting methods were selected as the research subjects using the convenient sampling method.The workplaceγradiation effective dose,radon concentrations,and radioactive activity concentrations were detected,and on-site surveys were conducted to estimate the internal and external irradiation doses and total effective doses for workers in different work sites.Results Radiological hazards in tunnels constructed using drlling and blasting methods included radon and its progeny,γradiation,radioactive dust(uranium-238,radium-226,thorium-232,and potassium-40)and others.The average total effective dose of ionizing radiation exposure for tunnel construction workers was(6.7301±1.5411)mSv.The average dose of radon and its progeny was(6.1630±1.5128)mSv,radioactive dust was(0.0146±0.0091)mSv,γradiation was(0.5526±0.1387)mSv.The dose of radioactive dust of radon and its progeny was 0.24%.Radon and its progeny contributed more to the radioactive dose than radioactive dust andγradiation(all P<0.05).Among all the radioactive dusts,the dose contribution ranked from highest to lowest was thorium-232,uranium-238,and radium-226.Conclusion For tunnel construction workers,the largest contribution to the effective dose of ionizing radiation exposure is from radon and its progeny for internal irradiation,followed byγradiation for external irradiation.The contribution of radioactive dust to internal irradiation dose can be considered negligible.