珠海口岸出入境邮件和快件中核与辐射调查研究

〔目的〕了解珠海口岸出入境邮件和快件的核与辐射水平,防止核与辐射通过邮件和快件在我国国境口岸传入和传出。〔方法〕采用便携式辐射检测仪和邮件核与辐射检测系统对出入境邮件和快件进行γ射线和中子射线检测。〔结果〕从出境的货车中,检测到18件(箱)重236kg陶瓷珠子γ射线剂量当量率为2.65μSv/h,为本底值的9.8倍,放射性核素含量238U为598±33 Bq/kg,232Th为625±5 Bq/kg。从入境的货车中,检测10包矿石色粉γ射线剂量当量率为16.5μSv/h,为本底值的61倍,放射性核素含量238U为4.30×103Bq/kg,226Ra为2.43×104Bq/kg,232Th为1.37×105Bq/kg,超过我国现行的标准值。〔结论〕需加强对邮件和快件的放射性监管,防止放射性超标的货物通过快递方式进出国境。

Investigation on Nuclear Rediation in Entry-exit Mail and Express Mail at Zhuhai Port

Objective To understand the content of nuclear radiation in entry-exit mail and express mail at Zhuhai Port.Method γ-rays and neutron rays in entry-exit mail and express mail were detected used by identifinder-N Radiation and TSA′s Conveyor Monitors.Result Gamma radiation dose equivalent rate in 18 boxes of Ceramic beads was 2.65μSv/h,and the Content of Radioactive nuclide was in the range of 238U,598±33Bq·kg-1,232Th,625±5 Bq·kg-1,respectively.Gamma radiation dose equivalent rate in 1 box of Mineral powder was 16.5 μSv/h,and the Content of Radioactive Nuclide was in the range of 238U,4.30×103Bq·kg-1,226Ra,2.43×1043Bq·kg-1,232Th,625±5 Bq·kg-1,respectively.Conclusion It is very necessary to stress radioactivity surveillance in the express mail.