Vibro-impact dynamics of complex engineering structures with applications to fretting of nuclear fuel bundles

复杂工程结构的振动冲击动力学及其在核燃料束微动磨损中的应用

• 批准号: 203167-2007
• 负责人: Yu, Shudong
• 金额: $ 1.31万
• 依托单位: Ryerson University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2007
• 资助国家: 加拿大
• 起止时间: 2007-01-01 至 2008-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=362449
• 关键词: Vibro; impact; dynamics; complex; engineering

In a nuclear reactor, presence of excessive vibrations of fuel bundles was found responsible for abnormal wear of the supporting structures or pressure tube. Failures of reactor components may lead to the partial loss of production or even complete shutdowns. Maintenance and replacement of severely worn components can be very costly. During operations, a string of fuel bundles are placed inside a fuel channel and are subjected to several sources of excitations including acoustic pressure pulsations, flow induced dynamic forces, etc.  Because of small clearances between fuel bundles structures and the pressure tube, even small amplitude vibrations (fretting) can cause impact and sliding periodically.   In this proposal, fretting of fuel bundle structures and contact-impact forces will be modeled for typical CANDU fuel bundles under various operating conditions. Although significant amount of research has been conducted to investigate the mechanisms of fretting, there is still a lack of a comprehensive understanding of fuel bundle fretting mechanisms for new fuel or existing fuel when operating conditions change. Quantification of fuel bundle vibrations is important for either case.  The Canadian nuclear industry is interested in developing a comprehensive fretting model. Such a model, once validated, will be invaluable for future certifications of new fuel designs by the regulatory authorities. Because of the complex configuration of fuel bundles, and their coupling with fluid flow, prediction of fretting requires dedicated research, rigorous modeling and experimental validation.  The main objectives are to advance understanding of the dynamic behaviors of structures, confined in liquid-flowing pipe, to study the effects of design changes, to aid the nuclear industry in developing a code and standard for fretting. Simulation results can be used to assess wear rate of pressure tube materials at all critical locations. Completion of this research proposal will assist the Canadian nuclear industry in achieving further technical success and certification of new CANDU nuclear fuel.

在核反应堆中，燃料束的过度振动被发现是导致支撑结构或压力管异常磨损的原因。反应堆组件的故障可能导致部分生产损失甚至完全停堆。严重磨损部件的维护和更换成本可能非常高。在运行过程中，一串燃料棒束放置在燃料通道内，并受到多种激励源的影响，包括声压脉动、流动引起的动态力等。由于燃料棒束结构和压力管之间的间隙很小，即使是小幅度的振动（微动）也会引起周期性的冲击和滑动。   在该提案中，将对各种运行条件下的典型 CANDU 燃料棒束结构的微动磨损和接触冲击力进行建模。尽管已经进行了大量的研究来研究微动磨损的机制，但仍然缺乏对新燃料或现有燃料在工况变化时的燃料管束微动磨损机制的全面了解。燃料束振动的量化对于这两种情况都很重要。  加拿大核工业有兴趣开发综合微动模型。这样的模型一旦得到验证，对于监管机构未来对新燃料设计的认证将具有无价的价值。由于燃料束的复杂配置及其与流体流动的耦合，微动预测需要专门的研究、严格的建模和实验验证。  主要目标是增进对液体流动管道中结构动态行为的理解，研究设计变更的影响，帮助核工业制定微动规范和标准。模拟结果可用于评估压力管材料在所有关键位置的磨损率。该研究计划的完成将有助于加拿大核工业取得进一步的技术成功并获得新型 CANDU 核燃料的认证。