Development of a sustainable solution for the elimination of helium in copper cold spray process for used nuclear fuel containers

开发可持续解决方案，消除废旧核燃料容器铜冷喷涂工艺中的氦气

• 批准号: 514654-2017
• 负责人: Jodoin, Bertrand
• 金额: $ 2.6万
• 依托单位: University of Ottawa
• 依托单位国家: 加拿大
• 项目类别: Collaborative Research and Development Grants
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=618242
• 关键词: Development; sustainable; solution; elimination; helium

Canadas nuclear reactors have produced almost 2.6 million used fuel bundles over the last decades. Thisnumber is expected to double over the next 40 years. Only very recently has Canada adopted a course of actionto deal with the long-term containment of the spent nuclear fuel, with the Nuclear Waste ManagementOrganization (NWMO) responsible for designing and implementing Canada's plan. Assessment of long-termsafe and secure management options has led to the development of a centralized containment and isolation ofCanada's used fuel in a deep geological repository (DGR). What differentiates the Canadian design from othersis the corrosion-resistant outer copper coating that is proposed. As opposed to existing dual-shell overpackdesigns (thick copper sleeve on steel shell), the corrosion resistant copper coating is thinner (3 mm thick) andintegrally bonded to the steel shell. This design reduces drastically the amount of copper required for each UFCand mechanical stresses on the steel shell. NWMO has selected electrodeposition to produce the coppercoatings on the steel vessels prior to loading them with used nuclear fuel bundles and closing them with acopper coated cap end. Cold Gas Dynamic Spraying (CGDS or cold spray) was selected as the preferredtechnique to complete the copper coating at the containment vessel and cap end junction (closure weld zone).NWMO is still seeking a new innovative way to alleviate the use of helium in the CGDS process. Analternative approach to enhance CGDS coating adhesion is the control of substrate temperature prior to particleimpact. This proposal aims to build on few limited studies that have highlighted the potential of substratepreheating as a surface preparation method prior to CGDS. It is envisioned that proper substrate heating priorto applying copper coating on steel by CGDS could result in enhanced coating adhesion strength (fromincreased mechanical and metallurgical bonds) and allow the use of nitrogen only as the process gas. Thiswould represent a safe, highly efficient and cost-effective solution for the CGDS coating of the closure weld zone.

在过去的几十年里，加拿大的核反应堆生产了近260万束用过的燃料束。这一数字预计将在未来40年内翻一番。直到最近，加拿大才通过了一项处理乏核燃料长期遏制问题的行动方针，由核废料管理组织负责设计和执行加拿大的计划。对长期、安全和有保障的管理选择的评估导致制定了一种集中控制和隔离加拿大深层地质储存库(DGR)中的废燃料的方法。加拿大的设计与其他设计的不同之处在于提出了耐腐蚀的外层铜涂层。与现有的双壳外包装设计(钢壳上厚的铜套)不同，耐腐蚀的铜涂层更薄(3毫米厚)，并且与钢壳整体结合。这种设计大大减少了每个UFC所需的铜量和钢壳上的机械应力。NWMO选择了电沉积在钢制容器上产生铜涂层，然后将用过的核燃料束装载到钢容器上，并用涂有铜涂层的帽端关闭它们。冷气动力喷涂(CGDS或冷喷涂)被选为在安全壳和帽端接头(闭合焊接区)处完成铜涂层的首选技术。NWMO仍在寻求一种新的创新方法来减少CGDS工艺中的氦使用量。提高CGDS涂层附着力的另一种方法是在颗粒冲击之前控制衬底温度。这项提议旨在建立在少数几项有限研究的基础上，这些研究强调了在CGDS之前将衬底预热作为一种表面准备方法的潜力。可以预见，在用CGDS在钢上涂覆铜涂层之前，适当的衬底加热可以提高涂层的结合强度(增加机械和冶金结合)，并允许只使用氮气作为工艺气体。这将是一种安全、高效和经济的闭合焊接区CGDS涂层解决方案。