核素在水平组件迁移的现场示踪试验

FIELD TRACER MIGRATION TEST OF NUCLIDES IN HORIZONTAL ASSEMBLY

在水平组件中的迁移试验是核素在含水层迁移试验的重要组成部分。本文主要介绍在中国辐射防护研究院野外试验场地下研究设施 (URF)试验竖井中进行的水平组件试验的方法和结果。水平组件中装有示踪剂和在含水层采集的未扰动土壤 ,通过试验竖井壁水平插入含水层 ,天然地下水通过与含水层介质紧密相连的一端流过组件 ,在接取样管的另一端接取水样 ;通过测量试验期间采集的水样和试验结束后切割的土壤样品中示踪剂的浓度 ,得到核素的迁移数据。试验结果表明 ,黄土对试验所用的90 Sr、2 3 7Np、2 3 8Pu和 2 41Am以及 Sr、Nd和 Ce都有较强或很强的吸附能力 ;核素迁移具有偏心现象 ;腐殖酸延缓了 90 Sr的迁移 ;3 H的迁移速度慢于 Br-。

The tracer migration test in horizontal assembly is an important part of the field tracer migration test of nuclides in aquifer. The method and results of the test, which was conducted in the experimental shaft of the CIRP′s Field Test Site, are introduced in this paper. The horizontal assemblies, in which tracers and undisturbed soil collected from the aquifer were filled, were inserted into the aquifer through the experimental shaft wall. Natural underground water flowed through the assemblies were collected in sampling bottles. The tracer concentrations in both water and soil samples were obtained. It is found from the results that loess has stronger capacity to sorb the nuclides, 90 Sr, 237 Np, 238 Pu, 241 Am, Sr, Nd and Ce, concentration distributions of tracers have eccentric phenomena, the humus retarded migration of 90 Sr as well as 3H migrated at slower velocity than Br -. (