高放废物处置库芨芨槽预选场址深部地下水同位素研究  

Isotopic Study of Deep Groundwater in Jijicao Preselected Site for China's High Level Radioactive Waste Disposal Repository

作　　者：郭永海[1] 王海龙[1] 董建楠[1] 苏锐[1] 刘淑芬[1] 周志超[1] 

机构地区：[1]核工业北京地质研究院,北京100029

出　　处：《地质学报》2013年第9期1477-1485,共9页Acta Geologica Sinica

基　　金：国家自然科学基金项目(编号91025020);"核设施退役及放射性废物治理专项"项目(编号中核计发2010-716)资助成果

摘　　要：深地质处置是目前国际上普遍接受的高放废物安全处置方案。对于这种方案而言,安全处置高放废物的前提是选择适宜的场址,而场址的适宜性在很大程度上取决于其水文地质条件。高放废物处置库场址需要低渗透岩体作为处置库围岩,对于低渗透岩体而言,经典和传统的水文地质研究方法受到了很大的限制,而同位素技术与其他水文地质方法结合时,却能发挥出良好的作用。本文以目前我国高放废物处置库预选场址之一的芨芨槽场址为例,重点讨论了同位素方法在花岗岩体场址水文地质研究中的应用。根据钻孔不同深度的地下水环境同位素（δD、δ~18O、3~H和14~C）组成特征,结合场址水文地质条件,识别了区内地下水的来源,揭示了控制地下水运移交替速率的主要因素。结果表明,该区深部地下水14~C年龄高达8000a左右,说明其交替、运移十分缓慢,但同时也含有少量的氚,说明地下水以侧向补给的＂老水＂为主,接受当地大气降水入渗补给的＂新水＂所占比例很小。此外,通过地下水14~C年龄与取样段岩芯采取率的对比,认识到对于区内的花岗岩体而言,决定地下水交替、运移速率的主要因素是裂隙的发育程度,而不是深度。At present, deep geological disposal scheme is widely accepted for high level radioactive waste disposal in the world. The precondition of high level radioactive waste safe disposal for this scheme is to select a feasible site. The feasibility of a site mainly depends on the hydrogeological conditions. A potential site for high level radioactive waste disposal needs very low-permeability rock body to isolate the waste. The use of classical and conventional methods is limited for the research of very low-permeability rock body. But isotope hydrology techniques can be particularly valuable when used in coniunction with other hydrogeological methods. This paper, taking Jijicao preselected site of high level radioactive waste disposal repository in our country at present stage as an example, mainly studied the isotopic methods used in site hydrogeological research in granite body. According to the environmental isotopic component characteristics of groundwater in different depths and combined with hydrogeological conditions, the origin of groundwater was recognized and the main factors controlling the velocity of groundwater movement and alternation in the site was explored. The results show that 14C age of deep groundwater in the area can reach about 8000 years which indicates the deep groundwater movement and alternation is very slow. But the deep groundwater also contains some tritium which indicates it is recharged mainly by ＂ old water＂ coming from lateral flow and the ＂ new water＂ recharged from infiltration of local rainfall if little in the deep groundwater. In addition, through comparison of 1~C age of deep groundwater with percentage of core recovery of water sampling section in the boreholes, it is known that the factor controlling the velocity of groundwater movement and alternation in the granite body in the site area is fissure characteristics, but not the depth.

关 键 词：高放废物处置库 深部地下水 同位素 14~C年龄 运移和交替 

分 类 号：TL942.2[核科学技术—辐射防护及环境保护]