Abstract Geologic disposal is a promising solution for a safe permanent isolation of accumulated high-level nuclear waste from nuclear powerplants. The behavior of host rock is highly coupled thermally, hydromechanically, and chemically. Numerical simulations of such coupled phenomena for the extremely long term (>100,000 years) and large length scale (>1 km) of geologic disposal remain to be computationally challenging. In this study, a methodology has been developed to approximate stress and stress-induced permeability change in host rock using only thermo-hydrological (TH) variables. A coupled thermo-hydromechanical (THM) simulation is carried out using TOUGH-FLAC simulator to model THM behaviors of a generic nuclear waste repository, in order to evaluate the performance of the developed methodology, which is implemented in a coupled TH simulation. Results show that stress and permeability change estimated by the developed methodology in the TH-coupled simulation match those calculated in the THM-coupled simulation over the simulated timeframe of over 10,000 years. Details about errors in stress and permeability estimates accrued by the developed methodology are discussed in this paper. The developed methodology will help incorporate stress-induced permeability change into existing TH simulators for the long-term radionuclide transport in geologic disposal.

中文翻译：

---

在热水耦合模拟中估计地质核废料储存库中的应力和应力引起的渗透率变化

摘要 地质处置是从核电厂安全永久隔离积累的高放核废料的一种有前途的解决方案。主岩的行为在热力、流体力学和化学上高度耦合。在超长期（> 100,000 年）和大尺度（> 1 km）地质处置中对此类耦合现象进行数值模拟在计算上仍然具有挑战性。在这项研究中，开发了一种方法来仅使用热水文 (TH) 变量来近似计算主岩中应力和应力引起的渗透率变化。使用 TOUGH-FLAC 模拟器进行耦合热流体机械 (THM) 模拟，对通用核废料储存库的 THM 行为进行建模，以评估所开发方法的性能，这是在耦合 TH 模拟中实现的。结果表明，在超过 10,000 年的模拟时间范围内，THM 耦合模拟中开发的方法估计的应力和渗透率变化与 THM 耦合模拟中计算的应力和渗透率变化相符。本文讨论了由开发的方法产生的应力和渗透率估计误差的详细信息。开发的方法将有助于将应力引起的渗透率变化纳入现有的 TH 模拟器，用于地质处置中的长期放射性核素传输。本文讨论了有关由开发的方法产生的应力和渗透率估计误差的详细信息。开发的方法将有助于将应力引起的渗透率变化纳入现有的 TH 模拟器，用于地质处置中的长期放射性核素传输。本文讨论了有关由开发的方法产生的应力和渗透率估计误差的详细信息。开发的方法将有助于将应力引起的渗透率变化纳入现有的 TH 模拟器，用于地质处置中的长期放射性核素传输。