【作者】 谭凯旋； 刘泽华； 曾晟； 冯松；

【Author】 TAN Kai-xuan,LIU Ze-hua,ZENG Sheng,FENG Song (School of Nuclear Resources and Nuclear Fuel Engineering,University of South China, Hengyang 421001,China)

【机构】 南华大学核资源与核燃料工程学院；

【摘要】 铀矿开采和水冶过程中所产生的尾矿是一种大规模低水平放射性物质,与尾矿库相关的典型的环境问题就是氡的析出,研究铀尾矿氡的析出机理是尾矿治理的基础。以衡阳272厂的铀尾矿为对象,通过室内实验测定了尾矿氡析出率随时间的变化,结果表明尾矿中氡析出率随时间呈现明显的振荡变化。非线性分析得出氡析出率时间序列的Lyapunov指数为0.1 566和0.4427,混沌吸引子分维值分别为4.55和4.49,其饱和嵌入维为8。氡的析出是一个混沌动力学过程,其动力学可用低维吸引子来描述,描述氡析出率随时间演化所需要的相关变量数的下限是5。尾矿的非均匀性、反冲、He-Rn团簇、孔隙中的分形扩散、近地面大气层的湍流扩散是引起氡析出混沌演化的可能机理。更多还原

【Abstract】 Multitude mill tailings,generated in the course of uranium mining and hydrometallurgy process,are low level radioactive materials.The typical environmental problem related to tailings reservoir is radon emanation,and the study on radon emanation mechanism of uranium mill tailings is the basis of tailing treatment.Taking uranium mill tailing of the 272 plant as example,the change of radon emanation mechanism of uranium mill tailings with the time was determined in laboratory.The result shows that the change of radon emanation mechanism of uranium mill tailings presents obvious vibrating shaped change with the time.Based on the nonlinear analysis,the Lyapunov exponent of radon emanation rate time series is 0.1566 and 0.4427,and the fractal dimension of chaotic attractor is 4.55 and 4.49, and the embeding dimension is 8.Radon emanation is a chaotic dynamical process,the dynamics can be described by low-dimensional attractor,and the lower limit of the correlated variables number,describing the evolution of radon emanation with time,is 5.The chaotic evolution of radon emanation may be induced by mechanism such as the heterogeneity of tailings,recoiling,He-Rn cluster,fractal diffusion in the pores,and turbulent diffusion in near-surface layer.更多还原