Degradation processes of nuclear waste container materials

几十年来，加拿大一直使用核反应堆来产生大量不排放的电力，保持一个可行的核工业对于履行我们在《泛加拿大清洁增长和气候变化框架》中概述的减少温室气体排放的集体承诺至关重要。安全、永久地处置乏核燃料是维持加拿大和世界各地核工业生存能力的一个必要步骤。这一研究项目是与核废料管理组织(核废料管理组织)合作进行的，它将提供所需数据库的重要组成部分，以开发对实现加拿大高放射性核废料的安全处置至关重要的绩效评估模型。该项目将调查核废料容器材料腐蚀和乏燃料溶解的基本过程。将对镀铜钢废物容器材料以及二氧化铀和模拟乏核燃料样品进行广泛的电化学、光谱、显微和表面分析实验。在镀铜钢试件上，将评估当深层地质核废料储存库的条件如预期那样从温暖和氧化演变为冷却和缺氧时可能发生的各种腐蚀过程。其目的将是确定：(1)在短期氧化期内保护底层钢免受地下水污染所需的铜腐蚀容限；(2)容器的整体寿命；(3)容器制造问题的后果，如吸氢和存在未检测到的透层缺陷。对于燃料，将检查燃料表面发生的各种化学过程的速率，目的是了解和量化辐射分解产生的氧化剂(例如过氧化氢)与氧化剂清除剂之间的相互作用，例如辐射分解产生的氢和钢制容器的腐蚀。这项工作将由瑞典和瑞士的核废料管理当局监督，这两个国家也遇到了类似的问题。

Canada has employed nuclear reactors to generate large amounts of non-emitting electrical power for several decades, and maintaining a viable nuclear industry will be essential to meeting our collective commitment to decreasing greenhouse gas emissions, as outlined in the Pan-Canadian Framework on Clean Growth and Climate Change. The safe, permanent disposal of spent nuclear fuel is one necessary step in maintaining the viability of the nuclear industry in Canada and around the world. This research project, performed in partnership with the Nuclear Waste Management Organization (NWMO), will furnish a critical part of the required database for the development of the performance assessment models essential to achieving the safe disposal of Canada's high level nuclear waste. This project will investigate the fundamental processes that underlie the corrosion of nuclear waste container materials and the dissolution of the spent fuel. A wide range of electrochemical, spectroscopic, microscopic and surface analytical experiments will be conducted on copper-coated steel waste container materials and on uranium dioxide and simulated spent nuclear fuel specimens. On copper-coated steel specimens, the various corrosion processes that could occur as the conditions in a deep geologic nuclear waste repository evolve, as anticipated, from warm and oxidizing to cool and anoxic, will be evaluated. The aim will be to determine; (i) the copper corrosion allowance necessary to protect the underlying steel against exposure to groundwater during the short-term oxidizing period, (ii) the overall lifetime of the containers, and (iii) the consequences of container fabrication issues, such as hydrogen absorption and the presence of undetected through-coating defects. For the fuel, the rates of the various chemical processes occurring on the fuel surface will be examined, with the objective of understanding and quantifying the interactions between oxidants produced by radiolysis (e.g., hydrogen peroxide) and oxidant scavengers, such as hydrogen from radiolysis and the corrosion of the steel vessel. The work will be monitored by nuclear waste management authorities from Sweden and Switzerland, where similar issues are encountered.