中低放核废料地下处置对围岩介质（花岗岩体）温度场的影响

在核废料的地下处置过程中，由于放射性元素的衰变，将产生大量的热量，因此，核废料的地下处置将影响围岩的温度场。初步探讨了中低放核废料的地下处置对围岩介质花岗岩体温度场的影响。     

花岗岩介质中处置中低放核废料的热应力

花岗岩介质是核废料地下处置的理想介质之一。在“中低放核废料地下处置对围岩介质（花岗岩体）温度场的影响”一文基础上,进一步探讨花岗岩介质中处置中低放核废料热应力效应,旨在为核废料的地质处置作一有益的探索。     

花岗岩介质中处理中低放核废料的热应力

花岗岩介质是核废料地下处理的理想介质之一。在“中低放核废料地下处置对围岩介质（花岗岩体）温度场的影响”一文基础上,进一步探讨花岗岩介质中处置中低放核房料热应力效应,旨在为核废料的地质处置作一有效的探索。     

微生物与核废料的长期管理

近年来,开发利用地下空间引起广泛关注,建设地下生态宜居城市、构建深地科学实验室进行科学探索等相关问题成为研究的热点.地下生活着种类繁多的微生物,它们包括古菌、细菌和真菌,这些地下微生物对开发利用地下空间起着不可忽视的作用.目前研究发现:在核废料的长期管理中,硫酸盐还原菌的活动会导致地下工程设施的腐蚀,地下微生物气体产量会导致地下空间气压变化,这些微生物作用都可能对核废料处置室和核废料容器的性能产生负面影响.概述了地下微生物的研究现状及其对核废料长期管理的影响.     

地质系统热-水-力耦合作用的随机建模初步研究

热-水-力(THM)耦合作用是岩石力学与环境地质中的重要基础理论问题,核废料地质处置库周围的缓冲材料和围岩中的热-水-力耦合现象将影响其力学稳定性、热传导性和渗透性,进而影响放射性核素在裂隙岩体中的迁移规律。核废料或放射性废料的地下深埋处置是国际上正在研究的永久性隔离的有效方法之一。因此,对核废料地质处置法安全性评估的一个重要内容就是对裂隙岩体中力学稳定性与构造应力、地下水渗流及热载荷等的耦合作用之数值模拟和评估。这已成为当前刻不容缓的重要的环境影响评价课题。笔者研究了温度场-渗流场-应力场中热传导系数和渗透率以及岩体力学参数的空间变异性,用实验方法研究三场耦合效应及裂隙岩体的场性能等效处理,试图建立热-水-力耦合作用的随机性数学模型及可视化数值模拟方法,为核废料地质处置安全性评估提供直观的新方法。     

泥岩核废料处置库温度-渗流-应力耦合参数敏感性分析

针对比利时HADES地下实验室PRACLAY现场加热试验,应用温度-渗流-应力耦合弹塑性模型,模拟现场加热过程中泥岩核废料处置库的水力学响应特征。采用单因素分析法,就泥岩热、水、力学参数对核废料处置库围岩孔压、温度、有效应力的影响进行了三维有限元分析。并基于参数敏感性分析结果,就温度、渗流、应力三场两两耦合作用对处置库围岩水力学响应的影响程度进行了系统分析。研究结果表明：泥岩热、水、力学参数中,渗透系数、弹性模量以及导热系数对加温所导致的超孔压的值影响较大;凝聚力、内摩擦角以及热膨胀系数对孔压的影响较小,但会显著影响围岩的有效应力;导热系数对围岩温度场的分布有决定性影响,温度传递的差异会显著影响围岩的孔压和有效应力;不同的热、水、力学参数对孔压、温度以及有效应力的影响机制是不同的,温度、渗流、应力三场两两耦合作用对围岩水力学响应的影响程度也存在显著的差异性。温度场对应力场、温度场对渗流场的耦合效应十分显著,加热后,围岩超孔压的产生以及热膨胀导致的有效应力变化会显著影响处置库的稳定。该研究结果在一定程度上可以为核废料处置库泥岩的热、水、力学参数的确定及耦合机制分析提供科学依据。     

国外核废料处置地质研究动向

笔者参加了第29届国际地质大会,现将会上了解到的关于核废料处置的一些研究动向介绍如下。大会设置的有关核废料处置的地质研究专题有“放射性和有害废料的地质处置”、“核废料处置研究计划”和“核废料处置地点特征及天然类比研究”。来自日本、法国、加拿大、芬兰、瑞典、比利时、俄罗斯、德国、英国和美国的代表在会议上交流了四十几篇论文。其中,法国和日本等核电大国代表的文章较多。从大会宣读和张贴的资料看,目前进行的核废料处置的地质研究工作主要有三个方面的内容。一是构造稳定性问题,其主要研究方向是放射性废料处置地点局部和区域上地质构造稳定程度的估价。二是地球化学问题,主要研究核废料中放射性有害物质在处置地点及其邻     

考虑溶质浓度影响的热-水-应力-迁移耦合模型及数值模拟

高放射性核废料地质处置库围岩中地下水的密度因溶质浓度不同而发生变化,这将影响到饱和-非饱和孔隙介质中近场和远场的热-水-应力耦合过程, 同时温度场、应力场也要对地下水中的核素及矿物质迁移产生作用。考虑这两个因素,建立和引入了相关的应力平衡方程、水连续性方程、能量守恒方程和渗透迁移方程,并研制出了对应分析孔隙介质中热-水-应力-迁移耦合问题的二维有限元程序。通过对一个假定的核废料地下处置库在核素泄漏后多场耦合过程的数值计算,考察了近场围岩中的温度、应力、孔隙水压力、核素浓度的分布及随时间的变化。结果初步显示了所建模型及程序可模拟热-水-应力-迁移耦合现象,因而具有一定的实用性。     

国外大口径钻孔处置核废料概况

本文简述了核废料地质处理方案和竖井—坑道处置系统,介绍了利用大口径钻孔处置固体核废料、液体核废料和竖井—坑道—大口径钻孔联合处置核废待的概况以及处置核废料的钻探设备、钻进技术、回填材料、填封技术、成本和施工周期.     

城市地质工作的新领域——城市垃圾处置现状及堆场选址地质工作初探

目前,国内外城市垃圾处置的方法主要是露天堆放、卫生填埋、焚烧、堆肥。对于核废料处置以地下填埋为主。国外垃圾处置的方向是推行焚烧及热分解,残渣进行填埋处理,达到资源化、能源化、无害化。我国是一个发展中的国家,地表与地下结合处置垃圾将是今后主要处理方式。垃圾处理场地质工作研究,对于我国水资源及环境保护具有重要意义。     

根据地球物理场特征评价核废物处置场址——对疏勒河断裂带稳定性评价

以疏勒河断裂带中段及其以北的北山地区遥感地质图象特征为基础，从该地区地球物理场（包括磁场、电磁场、射气场和地温场）特征的角度，对建造高放废物处置库的稳定性进行评价，得出结论：疏勒河断裂带中段及其北山地区的地质稳定性较好，是高放废物处置库选址的有利地区。     

Stability of expansive cement grout borehole seals emplaced in the vicinity of underground radioactive waste repositories

An expansive cementitious borehole plug emplaced in an underground opening in the vicinity of an underground nuclear waste repository may generate radial stresses on the walls of the opening due to an axial stress applied to the borehole plug and due to plug swelling. As these radial stresses may lead to the tensile fracturing of the rock, minimizing or preferably eliminating tensile stresses in rock is particularly important to preserve waste containment. Presented in this paper are the theoretical radial (normal) stress distribution and tensile strength in a borehole plug–rock system due to combined axial, thermal and lateral loading, along with analyses of plug–rock mechanical interactions in regards to borehole stability against tensile fracturing.     

Model of colloidal transportation of radionuclides by groundwater

The transportation of colloidal radionuclides by groundwater was subject to theoretical analysis. The far field of radioactive contamination of the underground environment (liquid waste pumping sites or storage of solidified waste) is dominated by pseudocolloids, i.e., colloidal particles of natural origin contaminated with radionuclides upon contact of groundwater with radioactive materials. Properties of real pseudocolloids were analyzed at sites of radioactive contamination of the underground environment. Based on a probabilistic approach, we developed a mathematical model of pseudocolloid transportation by groundwater, taking into account the difference in size of colloidal particles and the occurrence of nonradioactive natural particles with a similar composition in the groundwater. It is proved that nonuniform dimensions of the particles considerably affect the water transportation rate.     

核废料贮库围岩介质THM耦合的定解问题及其加权积分方程

以核废料贮库裂隙岩体介质热-液-力耗散过程的定力解方程为基础，结合核废料地下贮存，分析了热、液、力三方面的边值及初始条件。根据计算力学加权残值法，导出了定解问题的加权积分方程，为实现核废料贮库围岩介质THM耦合有限元数值计算，打下了理论基础。     

Seismogeological acceptance criteria for geological repositories for spent nuclear fuel

Qualitative geological acceptance criteria and quantitative seismological acceptance criteria for radioactive waste disposals are developed. The background material for the initiation of site selection and for its earthquake hazard assessment is discussed. The recent movements of the Earth's surface as well as the other mechanical properties of geological media, hydrological conditions of geological blocks, their groundwater chemistry, geochemical rheology, petrological analyses of rocks, etc., have to be taken into account. A new comprehensive integrated safety analysis of the final underground disposal of spent nuclear fuel has been underway in the Czech Republic since 1991. In accordance with these seismogeological acceptance criteria regions for building underground final radioactive waste disposals are singled out in the Czech Republic.     

长清井田环境水文地质特征分析与评价

在分析井田环境水文地质特征的基础上，利用浅层地下水的分析测试资料，依据水环境污染综合评价指数方法对浅层地下水环境质量的现状进行了评价。简要阐述了矿区开发对地下水资源可能造成的影响，矿区开发后地下水环境的一些变化趋势及初步预防措施，为将来矿井设计、建设和生产过程中浅层地下水环境的保护和利用提供了参考资料。     

Thermal stress analysis of underground openings

In the use of underground space for storage of solar energy, storage of excess heat from thermal power plants and containment of nuclear waste, the host medium is subjected to a thermal field accompanied by a thermal stress field. These stresses may endanger the stability and integrity of the structure. In this paper, the stress field, in circular and spherical openings, due to a given thermal field is analytically determined and numerically verified. Both lined and unlined openings are considered. The numerical and analytical results are in a satisfactory agreement. The lining stresses, support pressure and radial interface displacement depend only on the thermal field in the lining. A simplified method of stress computation applicable to a thin lining is also presented.     

Reversed mining and reversed-reversed mining: the irrational context of geological disposal of nuclear waste

Man does not only extract material from the Earth but increasingly uses the underground for storage and disposal purposes. One of the materials that might be disposed of this way is high-level nuclear waste. The development of safe disposal procedures, the choice of suitable host rocks, and the design of underground facilities have taken much time and money, but commissions in several countries have presented reports showing that — and how — safe geological disposal will be possible in such a way that definite isolation from the biosphere is achieved. Political views have changed in the past few years, however, and there is a strong tendency now to require that the high-level waste disposed of will be retrievable. Considering the underlying arguments for isolation from the biosphere, and also considering waste policy in general, this provides an irrational context. The development of new procedures and the design of new disposal facilities that allow retrieval will take much time again. A consequence may be that the high-active, heat-generating nuclear waste will be stored temporarily for a much longer time than objectively desirable. The delay in disposal and the counterproductive requirement of retrievability are partly due to the fact that earth-science organisations have failed to communicate in the way they should, possibly fearing public (and financial) reactions if taking a position that is (was?) considered as politically incorrect. Such an attitude should not be maintained in modern society, which has the right to be informed reliably by the scientific community.     

Influence of underground space development mode on the groundwater flow field in Xiong’an new area

The degree and scale of underground space development are growing with the continuous advancement of urbanization in China. The lack of research on the change of the groundwater flow field before and after the development of underground space has led to various problems in the process of underground space development and operation. This paper took the key development zone of the Xiong’an New Area as the study area, and used the Groundwater modeling system software (GMS) to analyse the influence on the groundwater flow field under the point, line, and surface development modes. The main results showed that the underground space development would lead to the expansion and deepening of the cone of depression in the aquifer. The groundwater level on the upstream face of the underground structure would rise, while the water level on the downstream face would drop. The “line” concurrent development has the least impact on the groundwater flow field, and the maximum rise of water level on the upstream side of the underground structure is expected to be approximately 3.05 m. The “surface” development has the greatest impact on the groundwater flow field, and the maximum rise of water level is expected to be 7.17 m.