^(85)Sr在非饱和黄土中的迁移特征  

Migration Characteristics of^(85)Sr in Unsaturated Loess

作　　者：王志明[1] 安永锋[1] 

机构地区：[1]中国辐射防护研究院,山西太原030006

出　　处：《原子能科学技术》2004年第1期29-34,共6页Atomic Energy Science and Technology

摘　　要：通过放射性核素在非饱和黄土中迁移的现场试验和实验室模拟实验可以看到:黄土对85Sr有较强的吸附能力;85Sr的延迟系数Rd不是常数,而随黄土中含水量θ的增加而增大;由分配系数kd按常用传统公式导出的Rd不仅大于实测值,而且随含水量的变化趋势也与实测结果相反;在天然降水条件下,85Sr的侧向浓度分布方差σ2y与纵向浓度分布方差σ2x相当,这表明,在降水入渗量甚小的非饱和黄土中,85Sr的侧向迁移是一不容忽视的因素;降水强度明显影响85Sr的纵向浓度分布方差,但对侧向浓度分布方差影响不大;85Sr迁移快成分影响着评价结果的保守性。这些特征极大地影响着下游关心点浓度的预测结果,从而极大地影响着污染物通过地质介质迁移的潜在危害的大小。From the results of two kinds of radionuclide migration tests in unsaturated loess conducted in the field and laboratory, it can be seen that loess has stronger sorption capacity for^85Sr; retardation coefficient, R_d, of^85Sr increases with water content θ rather than a constant; R_d derived according to conventional equation from distribution coefficient, k_d, obtained by batch in laboratory is more than the measured results; variation trend of the derived R_d with θ in unsaturated loess is contrary to the measured results; lateral concentration distribution variance, σ~2_y, is equivalent to longitudinal concentration distribution variance, σ~2_x, and can't be neglected under natural rainfall condition; rainfall rate affects obviously longitudinal expansion of^85Sr rather than lateral one; moreover, migration fast composition of^85Sr affects conservative level of assessment results. The characteristics mentioned above would considerably affect the predicted concentration of^85Sr at the concerned place towards lower reaches and hence affect considerably magnitude of potential risk to human.

关 键 词：^85Sr 非饱和黄土 迁移特征 放射性核素 吸附能力 废物处置 

分 类 号：TL942.1[核科学技术—辐射防护及环境保护]