摘要
为研究不同示踪源层材料对水份运移和核素迁移的影响 ,开展了以石英砂和黄土分别为示踪源层载体时 Sr、Nd、Ce在包气带中迁移的对比试验。试验历时 4 70 d,在两种源层条件下各取土芯样 4次。试验结果表明 :在喷淋强度为 5 mm/h、3h/d条件下 ,Nd和 Ce无论在石英砂示踪源层还是黄土示踪源层中浓度峰位均没有明显向下迁移 ;对于 Sr,在黄土示踪源层中 ,4 70 d后其峰位向下迁移约 15 cm(按质心计算为 10 cm左右 ) ,而从石英砂示踪源层中向下迁移不明显 (按质心计算 ,迁移约 2 .7cm) ,只是峰位有些展宽。上述结果表明 ,极薄 (7mm)的细石英砂层也能对非饱和入渗水产生明显屏流作用 ,使得核素从石英砂示踪源层中向下迁移速度减慢。
In order to study the influence of different tracer source layer material on nuclide migration behavior, the comparative test on stable elements Sr, Nd and Ce migration in aerated loess zone was carried out using loess and arenaceous quartz as the tracer source layer materials respectively. The test lasted 470 days. During the test, four times of sampling were done. The testing results indicate that under artificial sprinkling of 5 mm/h and 3 h/d, Nd and Ce not only in loess tracer source layer but also in arenaceous quartz tracer source layer did not obviously downwards migrated. Concentration peak of Sr for loess layer migrated down about 15 cm in 470 d (mass center moved down about 10 cm) but for arenaceous quartz layer the concentration peak of Sr did not obviously migrated down (mass center moved down about 2.7 cm). The test results show that very thin arenaceous quartz layer with thickness of 7 mm is also able to shield unsaturated water flow obviously. This is the main reason why the nuclides in arenaceous quartz layer migrate down slowly. (
出处
《辐射防护》
CAS
CSCD
北大核心
2002年第6期349-353,共5页
Radiation Protection
