血液辐照仪Ⅱ类放射源退役辐射监测与分析

Monitoring and Analysis of Decommissioning Radiation of Class Ⅱ Radioactive Sources of Blood Irradiators

目的:探讨血液辐照仪Ⅱ类放射源退役,为放射源退役、放射性物品运输、放射源应用场址无限制开放等项目的辐射安全管理与防护工作提供借鉴与指导。方法:以某血站血液辐照仪Ⅱ类放射源退役项目为例,对运输货包与运输车辆及周围开展辐射环境监测,评估人员受照剂量;对辐照室及周围监测,评估场址放射性污染水平,达到开放的目的。结果:该运输车辆周围各监测点的最高辐射剂量率为7.77 n Gy/h×10^(3)n Gy/h,血液辐照仪退役后的辐照室及周围的γ辐射剂量率为84.8 n Gy/h~115 n Gy/h,α、β表面污染均低于最低探测限(α<0.02 Bq/cm^(2),β<0.14 Bq/cm^(2));结论:项目退役过程中,放射源货包专用运输车辆周围的辐射剂量率低于GB 11806—2019的有关要求;在放射源启运后,原辐照室及周围环境的监测结果未见异常,表明场所未受到放射性污染,能够达到满足开放的要求。

Objective:To explore the decommissioning of class Ⅱ radioactive sources of blood irradiators,provide reference and guidance for radiation safety management and protection of projects such as radioactive source decommissioning,radioactive material transportation,and unrestricted opening of radioactive source application sites.Methods:Taking the decommissioning project of class Ⅱ radioactive sources of blood irradiators in a blood station as an example,the radiation environment monitoring is carried out on the transportation packages,transportation vehicles and surrounding areas,and the exposure dose of personnel is evaluated;the radiation room and surrounding areas are monitored to evaluate the radioactive pollution level of the site,to achieve the purpose of opening.Results:The maximum radiation dose rate of each monitoring point around the transport vehicle is 7.77×10^(3) n Gy/h,irradiation room and surrounding area after the decommissioning of blood irradiator γradiation dose rate is 84.8~115 n Gy/h,the surface contamination of α and β is lower than the minimum detection limit(α<0.02 Bq/cm^(2),β<0.14 Bq/cm^(2)).Conclusion:During the decommissioning of the project,the radiation dose rate around the special transport vehicle for radioactive source packages is lower than the relevant requirements of GB 11806-2019;after the radioactive source is shipped,the monitoring results of the original irradiation room and the surrounding environment are normal,indicating that the site is not radioactive pollution and can meet the opening requirements.