铀矿污染土壤γ剂量率与核素活度的表征关系

摘要/Abstract

摘要： 为了对铀矿冶退役治理源项调查作出快速、准确的判定,解决调查过程中存在的测量周期长、检测手段繁琐等问题。以某铀矿污染土壤为研究对象,通过分析铀系核素不平衡条件下的衰变特点,采用半无限大体源估算模式计算了不同垂深污染土壤所致表层关注点的γ剂量率,根据铀系核素的剂量率贡献及对不同垂深的影响,推导出土壤表层γ剂量率与核素活度的表征关系。结果表明:铀系核素所致关注点γ剂量率主要由^234mPa、²¹⁴Bi和²¹⁴Pb三个子体贡献,占比为96%;土壤表层(20 cm)污染核素所致关注点剂量率占比约为94%;根据铀系核素分段平衡理论及铀镭平衡系数,推导出以²³⁸U和²²⁶Ra为代表核素,与土壤表面γ剂量率的表征关系,经与实际监测结果进行对比,偏差在±5%以内。以此为依据可快速识别土壤的污染范围,提高源项调查监测布点的效率,为科学客观的开展污染土壤源项调查提供了新思路。

关键词: 铀矿, 污染土壤, 剂量率, 核素活度, 表征关系

Abstract: In order to quickly and accurately determine the pollution source terms for the decommissioning of uranium mines, and to solve the problems of long test cycle and cumbersome detection methods in the investigation process, the contaminated soil from uranium mines was used as research object in this paper. The decay characteristics under unbalanced conditions was analyzed, and the semi-infinite general source estimation model was used to calculate the γ dose rate of the surface concern points caused by the contaminated soil at different vertical depths. According to the dose rate contribution of uranium-series radionuclides and the effect on different vertical depths, the relationship between γ dose rate and radionuclide activity in soil surface layer was deduced. The results showed that the γ dose rate of the concern point caused by uranium series radionuclides is mainly contributed by the three daughters ^234mPa, ²¹⁴Bi and ²¹⁴Pb, which accounted for 96%. The dose rate of concern points caused by polluted radionuclides in the soil surface layer (20 cm) accounts for about 94%. According to the segmental equilibrium theory and the uranium- radium equilibrium coefficient, the characterization relationship between ²³⁸U and ²²⁶Ra as the representative radionuclides and the γ dose rate on the soil surface is deduced, compared with the actual monitoring results, the error was within ±5%. Based on this, the scope of the polluted soil could be quickly identified, the efficiency of source item investigation and monitoring distribution could be improved, and new ideas for scientific and objective in source item investigation of polluted soil could be provided.

Key words: uranium mine, contaminated soil, dose rate, radionuclide activity, characterization relationship

中图分类号:

杜娟, 冀东, 刘晓超, 侯铁钢. 铀矿污染土壤γ剂量率与核素活度的表征关系[J]. 辐射防护, 2024, 44(2): 160-166.

DU Juan, JI Dong, LIU Xiaochao, HOU Tiegang. Characterization relationship between gamma dose rate and radionuclide activity in uranium-contaminated soil[J]. RADIATION PROTECTION, 2024, 44(2): 160-166.

参考文献

[1] 李韧杰, 潘英杰, 周星火, 等. 铀矿冶设施退役与环境治理[M]. 北京: 原子能出版社, 2001.
LI Renjie, PAN Yingjie, ZHOU Xinghuo, et al.Decommissioning of uranium mining and metallurgical facilities and environmental treatment[M]. Beijing: Atomic Energy Press,2001.
[2] UNSCEAR. Sources and effects of ionizing radiation:UNSCEAR 2000 Report to the General Assembly, with scientific annexes [M]. United Nations, New York, 2000.
[3] Abdelouas A. Uranium mill tailings: Geochemistry, mineralogy, and environmental impact[J]. Elements, 2005,2(6):335-341.
[4] Yin M L, Zhou Y T, Tsang D C W,et al. Emergent thallium exposure from uranium mill tailings[J]. Journal of Hazardous Materials,2021,407:124402.
[5] 蒋文波,高柏,张海阳,等.某铀矿区周边土壤²³⁸U和²²⁶Ra分布特征及污染评价[J].中国环境科学,2021,41(4):1799-1805.
JIANG W B, GAO B, ZHANG H Y, et al. Distribution characteristics and pollution assessment of ²³⁸U and ²²⁶Ra in soils surrouding a uranium ore area[J]. China Environmental Science, 2021,41(4):1799-1805.
[6] 薛清泼,魏浩,张国瑞,等. 某铀矿区周边土壤典型重金属污染特征及植物筛选[J].中国矿业,2019,28(6):81-88.
XUE Qingpo, WEI Hao, ZHANG Guorui, et al. Pollution characterisatics of typical heavy metals in soil and plant screening around a uranium mine[J]. China Minine Magazine, 2019, 28(6):81-88.
[7] Lamarsh J R, Baratta A J. Introduction to Nuclear Engineering[M].New York: Prentice Hall, 2001:511-515.
[8] International Atomic Energy Agency. http://www.nndc.bnl.gov/nudat2/reCenrer.jsp?n=143&z=91.
[9] 李德平, 潘自强. 辐射防护手册(第一分册) 辐射源与屏蔽[M]. 北京: 原子能出版社, 1987: 158-160.
LI Deping, PAN Ziqiang. Radiation protection handbook (Volume 1) radiation sources and shielding [M].Beijing: Atomic Energy Press,1987: 158-160.
[10] 卢希庭. 原子核物理[M]. 北京: 原子能出版社, 2008:27-35.
LU Xiting. Nuclear physics[M].Beijing: Atomic Energy Press,2008:27-35.
[11] 张建, 张庆贤, 胡建伟, 等. 稀土废渣现场γ射线剂量率分段计算方法[J]. 同位素, 2020, 33(3): 156-162.
ZHANG Jian, ZHANG Qingxian, HU Jianwei, et al. The on-site gamma-ray dose rate piecewise calculation method for rare earth tailings[J]. Journal of Isotopes, 2020, 33(3): 156-162.
[12] 陆志仁. 不平衡铀系和锕铀系的放射性活度计算[J].辐射防护, 1984,4(5):366-376.
LU Zhiren. Calculation of radioactivity of non-equilibrium uranium and actinium-uranium series[J]. Radiation Protection, 1984,4(5):366-376.
[13] 章晔, 华荣洲. 放射性方法勘查[M]. 北京: 原子能出版社, 1990.
ZHANG Ye, HUA Rongzhou. Radioactive method survey[M]. Beijing: Atomic Energy Press,1990.
[14] Grove Software, Inc. Microshield^® User’s Manual[Z]. 2020.https://radiationsoftware.com.
[15] 中核浙江衢州铀业有限责任公司.771军工核设施退役治理Ⅰ期工程源项调查报告[R]. 2009.
[16] 国家环境保护局. 中国环境天然放射性水平[M]. 北京: 国家环境保护局, 2015.
State Environmental Protection Administration. Environmental natural radioactivity levels in China[M]. Beijing:State Environmental Protection Administration,2015.
[17] 生态环境部,国家市场监督管理总局. 铀矿冶辐射防护和辐射环境保护规定:GB 23727—2020[S].北京:中国标准出版社,2021.
Ministry of Ecology and Environment, PRC, State Administration for Market Regulation. Regulations for radiation protection and radiation environment protection in uranium mining and milling: GB 23727—2020[S]. Beijing: China Standard Press,2021.
[18] 施宸皓,梁婕,曾光明,等.某废弃铀矿周围农田土壤重金属和放射性元素的风险分析和修复措施[J].环境工程学报,2018,12(1):213-218.
SHI Chenhao, LIANG Jie, ZENG Guangming, et al. Assessment of heavy metal and radionuclide pollution risk in farmland around an abandoned uranium mine and its related remediation measures[J]. Chinese Journal of Environmental Engineering, 2018,12(1):213-218.
[19] 郑立莉,周仲魁,饶苗苗,等. 华东某铀矿区周围河流表层沉积物的天然放射性评价[J]. 生态毒理学报,2020,15(2):260-267.
ZHENG Lili, ZHOU Zhongkui, RAO Miaomiao, et al. Natural radioactivity evaluation of surface sediments of rivers around a uranium minging area in east China[J]. Asian Journal of Ecotoxicology, 2020,15(2):260-267.
[20] 生态环境部. 环境γ辐射剂量率测量技术规范: HJ 1157—2021[S]. 北京: 中国标准出版社, 2021.
Ministry of Ecology and Environment, PRC. Technical specification for the measurement of environmental gamma radiation dose rate: HJ 1157—2021[S]. Beijing: China Standard Press,2021.