核素在非饱和黄土介质中的二维迁移  

Two-dimensional radionuclide migration in unsaturated loess

作　　者：王志明[1] 李书绅[1] 金月如[1] 樊耀国[1] 马如维[1] 

机构地区：[1]中国辐射防护研究院,太原030006

出　　处：《核技术》2002年第8期619-623,共5页Nuclear Techniques

摘　　要：试验结果表明 ,天然降水条件下 ,在近 3年的试验期间 ,6 0 Co、85Sr和134 Cs三种核素在非饱和黄土介质中的比活度分布质心仍在示踪源层之内 ,85Sr的侧向比活度分布方差与纵向比活度分布方差相当 ;在人工喷淋条件下 ,这些核素的迁移距离也很短 ,说明非饱和黄土对这些核素有较强的吸附滞留能力。或者换句话说 ,非饱和黄土可以作为中低放废物处置的候选地质介质。另外 ,根据对试验结果的拟合与分析看出 ,降水入渗量极大地影响着核素向下的迁移速度和纵向扩展 ,因此 ,控制流经处置库的入渗水量 。It can be seen from the tracer migration test results that the centers of mass of specific activity distribution of radionuclides, 60 Co, 85 Sr and 134 Cs, in unsaturated loess medium are still within tracer source layer under natural rainfall condition during about 3 years. And lateral specific activity distribution variance of 85 Sr is equivalent to that of longitudinal distribution. Migration distances of the radionuclides under artificial sprinkling condition are also small. It is shown from the result that unsaturated loess has stronger sorption capacity to the radionuclides. In other words, unsaturated loess can be one of the candidate of geological media for disposal of ILRW. Moreover, it can be seen that the amount of water infiltration affects obviously downward migration velocity and longitudinal spread of radionuclide, and hence control of water infiltration amount through repository is a very important measure for decreasing effect of radionuclides in disposed waste on environment according to fitting and analyses to the tracer migration test results.

关 键 词：黄土介质 二维迁移 非饱和带 现场示踪试验 放射性核素 放射性废物 近地表处理 

分 类 号：TL942.1[核科学技术—辐射防护及环境保护]