Abstract Low permeability rocks provide an attractive option for disposal of radioactive waste because transport of radionuclides will be diffusion dominated and hence slow. However, heat generated by the waste will cause an increase in the pore pressure which may become high enough to damage the rock creating higher permeability areas and faster radionuclide transport paths. It is therefore important to understand the magnitude of pore pressure changes caused by the heating effect of the waste, to develop confidence that the rock will maintain its low permeability. This paper considers coupled Thermal-Hydraulic-Mechanical (THM) modelling of two experiments at the Meuse/Haute-Marne URL: the TED experiment at 1/5th scale and the ALC experiment at full repository scale. Modelling these experiments has enabled testing of understanding of key processes and parameterisation through a blind prediction of the results of the ALC experiment based on modelling of the TED experiment. Calibration of models to both experimental data sets has improved understanding of the importance of processes and parameters in determining pore pressures. The modelling captures the key features of the experiment, demonstrating that the physical processes are well represented in the model whilst spatial variability of physical properties can lead to significant uncertainties in pore pressure estimates. The work demonstrates the benefits of conducting experiments at full-scale, ideally located close to the repository site, and of building a good understanding of the spatial variability of the host rock properties.

中文翻译：

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低渗透性主岩中放射性废物处置的孔隙压力响应

摘要 低渗透性岩石为放射性废物的处置提供了一种有吸引力的选择，因为放射性核素的运输将以扩散为主，因此速度缓慢。然而，废物产生的热量会导致孔隙压力增加，孔隙压力可能变得足够高以损坏岩石，从而产生更高的渗透率区域和更快的放射性核素传输路径。因此，了解废物热效应引起的孔隙压力变化的幅度非常重要，以建立对岩石将保持其低渗透性的信心。本文考虑了 Meuse/Haute-Marne URL 的两个实验的耦合热-液压-机械 (THM) 建模：1/5 比例的 TED 实验和完整存储库规模的 ALC 实验。通过对基于 TED 实验建模的 ALC 实验结果的盲目预测，对这些实验进行建模使得能够测试对关键过程和参数化的理解。对两个实验数据集的模型校准提高了对确定孔隙压力过程和参数重要性的理解。该建模捕获了实验的关键特征，证明物理过程在模型中得到了很好的体现，而物理特性的空间可变性会导致孔隙压力估计的显着不确定性。这项工作证明了在靠近处置库地点的理想位置进行全尺寸实验的好处，以及对母岩性质的空间变异性建立良好理解的好处。