舟山口岸进口燃煤中放射性核素含量调查分析

Investigation of content of radioactive nuclide in imported coal of Zhoushan port

选取澳大利亚、俄罗斯和印尼2015~2016年度170批次燃煤样品,采用高纯锗γ谱仪分析燃煤样品中放射性核素活度浓度,对舟山口岸进口燃煤中放射性核素的活度进行分析及评价。所有样品中均有检测放射性核素40 K、238 U、226 Ra和232 Th,其最大值分别为212.8 Bq/kg、464.3Bq/kg、62.8Bq/kg和33.5Bq/kg。比活度在600.0Bq/kg以上的样品占总量的5.71%,检测结果除232 Th外,40 K、238 U和226 Ra均高于国外同类报道。实验结果与国内燃煤检测结果相比,天然放射性核素除40 K以外,均普遍高于国内燃煤放射性核素活度平均值。舟山口岸进口燃煤放射性核素40 K、238 U、226 Ra和232 Th活度浓度均低于免管限量(≤1 000.0Bq/kg),不会危害燃煤质量安全,但考虑到天然放射性核素的生物效应和富集因素,仍应加强对进口燃煤中放射性核素的监测力度以保障我国进口燃煤的质量安全。

Selecting 170 batches of fuel coal sample in 2015～ 2016 from Australia,Russia and Indonesia,using high purity germanium（HPGe）gamma-ray spectrometer,the activity concentrations of radioactive nuclide in fuel coal samples were analyzed,the analysis and evaluation of specific activity values of radioactive nuclide in imported coal at Zhoushan Ports were done.All samples tested contained ^40 K,^238 U,^226 Ra and ^232 Th,with the maximum amount of 212.8 Bq/kg,464.3 Bq/kg,62.8 Bq/kg and 33.5 Bq/kg respectively.The samples with the specific activity above 600.0 Bq/kg accounted for 5.71%of the total,^40 K,^238 U and ^226 Ra were higher than foreign reports except 232 Th.The results of this study and results of the domestic coal were compared,the natural radionuclides were generally higher than the average values of the domestic coal radionuclides except 40 K.The activity concentration of radionuclide in the imported coal at Zhoushan Port were all less than the free limit（1 000 Bq/kg）,the coal would not be harmful to coal quality and safety,however,because of the biological effect and the enrichment of natural radionuclides,we should strengthen the monitoring of the radioactive nuclide in imported coal and guarantee the quality and safety of Chinese imported coal.