高放核废物地质处置中工程屏障研究新进展

中国对该课题的研究始于1985年，但是长期以来未能引起足够的关注，相关研究项目也非常有限。近年来，随着中国经济的快速增长，能源短缺问题越来越严重，发展和利用核能己作为一种主要的解决方案，因此核废物的安全处置则成为现实的重要课题。中国在利用膨润土作为工程隔绝材料方面的研究工作，主要限于选择合适的膨润土，而高庙子膨润士作为最终选择的缓冲材料，其基本物理-化学特性已得到确定，但有关热-水-力耦合的试验尚未开展，相关课题的研究也尚需努力。鉴于国际上已对多种其他备选膨润土进行过大量研究，有关成果可望用于指导即将在中国进行的高庙子膨润土试验研究。此文的主要目的就是为中国核废物的地质处置研究提供一些有益的经验。首先，介绍使用基于膨润土的工程隔绝核废物地质处置方法，这一方法已为广泛接受；然后，介绍膨润土的选择标准，地质-化学特性、热-水-力性态（包括微观结构、宏观性态、接缝性态和数值分析），以及在放射性废物处置过程中产生的气体对工程隔绝层的影响等，通过不同实例来展示试验原理和主要结果；最后，对近期国内外研究成果和未来发展前景进行总结。

RECENT ADVANCES IN RESEARCH ON ENGINEERED BARRIER FOR GEOLOGICAL DISPOSAL OF HIGH-LEVEL RADIOACTIVE NUCLEAR WASTE

In China,the issue of nuclear waste disposal was started in 1985,but without paying significant attention and therefore the progress has been quite limited. Recently,with the impressive economic boom in China,energy shortage has become a more and more serious problem. In this study,nuclear energy is considered as one of the alternative solutions. Obviously,the issue on nuclear waste disposal becomes important actuality. In this paper,the research state in China about the bentonite as engineered barrier material was first presented. As a whole , the selection of Gaomiaozhi(GMZ) bentonite as buffer material has been performed , and its physicochemical characteristics have been identified. No thermo-hydro-mechanical(THM) tests have been carried out yet. Considering that significant work has been performed over the world on other candidate bentonites,it seems to be of benefit to have an overview on the recent advances in order to better orientate the future researchwork on GMZ bentonite. The main aim is therefore to provide some helpful experience and perspectives for the study on geological disposal of nuclear waste in China. Firstly,the disposal method is presented by using bentonite-based engineered barrier. It corresponds to the widely accepted concept,and no further research seems to be needed on this question. Secondly,the selection criteria of bentonite,its geochemical properties, thermo-hydro-mechanical behaviors including the relationship between microstructure and macroscopic behaviour,as well as the joint behaviour and numerical analysis,influence of gas generation during radioactive waste disposal on the engineered barrier are introduced. Different examples are given to illustrate either the experimental principle or the main results obtained. As mentioned above,only the issue on bentonite selection has been dealt with in China;and other issues should be studied with energy. Finally,some recent achievements are summarized and some perspectives are given.