Thermo-Hydro-Mechanical Processes in Evolving Multi-Phasic Geomaterials, Interfaces and Geoenvironmental Endeavours

演化的多相岩土材料、界面和地质环境努力中的热水力机械过程

• 批准号: RGPIN-2021-02650
• 负责人: Selvadurai, Antony
• 金额: $ 3.79万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=742132
• 关键词: Thermo; Hydro; Mechanical; Processes; Evolving

Developing feasible techniques for disposal of hazardous, heat emitting nuclear fuel waste is a critical environmental concern to many countries that store their waste at reactor sites, which, as they age, become increasingly unsuitable for safely storing the waste. Events in Fukushima have emphasized the vulnerability of temporary storage sites; safe disposal strategies must address the cradle-to-grave cycle and restore nuclear energy as a viable option to reduce reliance on fossil fuels. Many countries favour the creation of a Deep Geologic Repository (DGR) in stable geologic formations to contain the stored waste and prevent release to the geosphere and the biosphere. The favoured geologic media varies by country; clay deposits in Belgium, argillaceous rocks in France, granitic rock masses in Canada, Finland, Japan, Sweden and Switzerland, salt formations in Germany, arid geologic media in China, sedimentary rock formations in the UK and Spain and porous tuff in the USA. Since the 1960's Canada has considered locating a DGR for high-level nuclear waste in the Canadian Shield and possibly a DGR for short-lived low- to intermediate-level nuclear waste in the argillaceous rock formations of southern Ontario. Developing a DGR is not routine; strict environmental controls must be in place with a series of engineered barriers to minimize both short- and long-term release of radionuclides to the environment. Any rock mass that houses a DGR is a key element in a disposal concept and should act as a natural geologic barrier to retard radionuclide migration in the long term. The Thermo-Hydro-Mechanical (THM) behaviour of intact rocks and defects such as fractures are critical factors that will decide the efficacy of a DGR concept. The mechanical, fluid flow and thermal properties of rocks can be altered by the creation of a storage vault and by the thermal loading by the stored waste. The long-term impacts on the DGR, ranging from groundwater flow alterations due to climate change, glacial advance and other processes such as induced earthquakes, need to be accounted for in the safety assessment. Most importantly, the performance of the DGR needs to be investigated for time scales that transcend conventional engineering endeavours. Suitable mathematical models of THM processes and experimental techniques, have to be developed to evaluate the parameters characterizing the multi-physics processes. The mathematical models have to be implemented in computational procedures to predict the performance of a DGR at time scales of interest to long-lived radioactive wastes. These important research components will lead to the implementation of a successful deep geologic disposal strategy in Canada. The over-arching findings related to THM research examined in this proposal can also enhance our understanding of both leakage of sequestered greenhouse gases and methane from defective interfaces and ground subsidence due to water and resource extraction.

对于许多将废物储存在反应堆场地的国家来说，开发可行的技术来处置危险的、发热的核燃料废物是一个关键的环境问题，随着反应堆的老化，这些废物越来越不适合安全储存废物。福岛事件凸显了临时储存地点的脆弱性；安全处置战略必须解决从摇篮到坟墓的循环问题，并恢复核能作为减少对化石燃料依赖的可行选择。许多国家赞成在稳定的地质构造中建立深层地质处置库（DGR），以容纳储存的废物并防止释放到地质圈和生物圈。不同国家喜欢的地质介质有所不同；比利时的粘土矿床，法国的泥质岩，加拿大、芬兰、日本、瑞典和瑞士的花岗岩岩体，德国的盐层，中国的干旱地质介质，英国和西班牙的沉积岩层以及美国的多孔凝灰岩。自 1960 年代以来，加拿大一直考虑在加拿大地盾中建立一个用于高放核废料的 DGR，并可能在安大略省南部的泥质岩层中建立一个用于短期中低放核废料的 DGR。开发 DGR 并不是例行公事；必须实施严格的环境控制，并设置一系列工程屏障，以最大限度地减少放射性核素向环境的短期和长期释放。任何含有 DGR 的岩体都是处置概念中的关键要素，并且应充当天然地质屏障，以长期阻止放射性核素迁移。完整岩石的热-水-机械 (THM) 行为和裂缝等缺陷是决定 DGR 概念有效性的关键因素。岩石的机械、流体流动和热特性可以通过建立储存库和储存废物的热负荷来改变。安全评估中需要考虑对 DGR 的长期影响，包括气候变化、冰川推进和诱发地震等其他过程引起的地下水流变化。最重要的是，需要在超越传统工程努力的时间尺度上研究 DGR 的性能。必须开发合适的 THM 过程数学模型和实验技术来评估表征多物理过程的参数。数学模型必须在计算程序中实施，以预测 DGR 在长寿命放射性废物感兴趣的时间尺度上的性能。这些重要的研究组成部分将导致加拿大成功实施深层地质处置战略。本提案中与 THM 研究相关的总体发现也可​​以增强我们对封存温室气体和甲烷从有缺陷的界面泄漏以及由于水和资源开采而导致的地面沉降的理解。