Corrosion of Spent Nuclear Fuel and High-Level Waste Glass in Anoxic Clay Disposal Environment – Technical Note

Many countries are pursuing deep geologic disposal of spent nuclear fuel (SNF) and/or high-level waste (HLW) glass in carbon steel containers in anoxic clay (and/or bentonite backfill) environments. If water contacts the nuclear material due to container failure by corrosion, corrosion (i.e., traditional dissolution) of SNF and/or HLW glass will occur potentially resulting in radionuclide release to the geosphere. Studies, generally independent of each other, have been conducted on corrosion of containers, corrosion of SNF and HLW glass, and radionuclide transport in the geological disposal setting. The output of these efforts is abstracted into integrated system performance assessments (PAs) in order to analyze the safety associated with generic deep geologic disposal systems of SNF and/or HLW glass (together also called HLW). This technical note considers the application of laboratory experimental test results from multiple research programs in the United States, Canada, Japan, and the European community on corrosion of SNF and/or HLW glass and mass transport in the clay/bentonite medium of a repository system. These studies also include work by staff at the U.S. Nuclear Regulatory Commission (NRC) and the Center for Nuclear Waste Regulatory Analyses (CNWRA). These are available to the public separately. Important examples include Ahn and Gwo (2020); and Pan and Ahn (2020, and 2018). In this additional paper-specific consideration is given to the corrosion of SNF and HLW glass controlled by aqueous transport of dissolved species in the aqueous media as the media is reaching solubility (or steady state) limits of the dissolved species.诸多国家正推进乏燃料（spent nuclear fuel, SNF）与/或高放废物（high-level waste, HLW）玻璃的深地质处置工作，具体为将其封装于碳钢容器内，置于缺氧黏土或膨润土回填材料构成的处置环境中。若因容器腐蚀失效致使水接触核物料，则乏燃料与/或高放废物玻璃将发生腐蚀（即传统溶解过程），进而可能引发放射性核素向地质圈的释出。此前学界已针对容器腐蚀、乏燃料与高放废物玻璃腐蚀，以及地质处置场景下的放射性核素输运开展了多项相互独立的研究。上述研究成果被整合至综合系统性能评价（system performance assessments, PAs）中，用于分析乏燃料与/或高放废物玻璃（二者亦可统称为高放废物）的通用深地质处置系统的安全性。 本技术说明旨在整合美国、加拿大、日本及欧盟多项研究计划中，关于乏燃料与/或高放废物玻璃腐蚀，以及处置库系统黏土/膨润土介质内质量输运的实验室实验测试成果。此类研究还涵盖了美国核管制委员会（U.S. Nuclear Regulatory Commission, NRC）与核废物监管分析中心（Center for Nuclear Waste Regulatory Analyses, CNWRA）工作人员的相关工作，上述成果均可单独面向公众开放获取。典型研究案例包括Ahn与Gwo（2020）以及Pan与Ahn（2020、2018）的相关工作。 本技术说明还专门针对当水介质中溶解物质达到溶解度（或稳态）极限时，由溶解物质水相输运调控的乏燃料与高放废物玻璃腐蚀过程展开探讨。