Degradation processes of nuclear waste container materials

几十年来，加拿大一直利用核反应堆生产大量无排放电力，维持一个可行的核工业对于履行我们减少温室气体排放的集体承诺至关重要，正如《泛加拿大清洁增长和气候变化框架》所概述的那样。安全、永久地处置用过的核燃料是维持加拿大和全世界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（核废物组织）合作进行的，它将提供所需数据库的一个关键部分，以发展安全处置加拿大高水平核废料所必需的业绩评估模式。这个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。将对镀铜钢废料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、微观和表面分析实验。对镀铜钢试样，将评估随着深层地质核废料储存库条件的演变，如预期的那样，从温暖和氧化到寒冷和缺氧，可能发生的各种腐蚀过程。其目的将是确定；(i)在短期氧化期间保护底层钢材免受地下水暴露所必需的铜腐蚀余量，（ii）容器的整体寿命，以及（iii）容器制造问题的后果，例如氢气吸收和未检测到的穿透涂层缺陷的存在。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）和氧化剂清除剂（例如辐射分解产生的氢和钢容器的腐蚀）之间的相互作用。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.