Clay Hydration, Drying, and Cracking in Nuclear Waste Repositories

核废料处置库中的粘土水合、干燥和裂解

• 批准号: EP/X011615/1
• 负责人: Jon Harrington
• 金额: $ 41.99万
• 依托单位: British Geological Survey
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FX011615%2F1
• 关键词: Clay; Hydration; Drying; Cracking; Nuclear

The design of geologic repositories for high-level waste (HLW) and spent nuclear fuel (SNF) remains an incompletely resolved question in the nuclear fuel cycle despite significant advances over the last several decades. A key theme in current designs is the multibarrier concept, whereby several layers of barrier materials, from canisters to EBS to low-permeability host rock, ensure the isolation of the waste. An important role is played by the Engineered Barrier System (EBS), which must maintain adequate sealing capacity (i.e., low hydraulic permeability, mechanical integrity) around the waste canisters for durations of thousands of years while exposed to (i) large thermal gradients caused by heat released by the waste; (ii) large geochemical gradients due to corrosion and ion-exchange reactions at the canister-EBS and EBS-host rock interfaces; and (iii) large geomechanical gradients driven by capillary stresses associated with the initial EBS rehydration, water evaporation and, later, with the possible generation of gases at the canister-EBS interface through corrosion and hydrolysis reactions. The objective of this project is to develop a new multi-scale simulation approach to predict the coupled thermal-hydrologic-mechanical-chemical (THMC) evolution of an engineered clay barrier in the near field of a geological repository for HLW and SNF.

尽管在过去几十年中取得了重大进展，但高放废物（HLW）和乏核燃料（SNF）地质处置库的设计仍然是核燃料循环中尚未完全解决的问题。当前设计的一个关键主题是多层屏障概念，即从罐到 EBS 再到低渗透性主岩的多层屏障材料，确保废物的隔离。工程屏障系统（EBS）发挥着重要作用，它必须在废物罐周围保持足够的密封能力（即低水渗透性、机械完整性）长达数千年，同时暴露于（i）引起的大热梯度通过废物释放的热量； (ii) 由于罐-EBS 和 EBS-主岩界面处的腐蚀和离子交换反应而产生大的地球化学梯度； (iii) 由毛细管应力驱动的大地质力学梯度，该毛细管应力与最初的 EBS 再水化、水蒸发以及随后通过腐蚀和水解反应在罐-EBS 界面处可能产生的气体有关。该项目的目标是开发一种新的多尺度模拟方法，以预测 HLW 和 SNF 地质处置库近场工程粘土屏障的热-水文-机械-化学 (THMC) 耦合演化。