The micromechanics of fracture of hydrides in Zr-2.5Nb CANDU pressure tubes

Zr-2.5Nb CANDU压力管中氢化物断裂的微观力学

• 批准号: 560391-2020
• 负责人: Abdolvand, HamidrezaHA
• 金额: $ 3.01万
• 依托单位: University of Western Ontario
• 依托单位国家: 加拿大
• 项目类别: Alliance Grants
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=759779
• 关键词: micromechanics; fracture; hydrides; Zr; 2.5Nb

CANDU reactors have been contributing significantly in providing clean energy to Ontario and Canada. More than 50% of electricity in Ontario is generated by CANDU reactors. Most of CANDU reactors are built in 1970s and 1980s and are aging. In order to continue to operate these reactors, engineers are required to demonstrate to regulatory authorities that they are safe. One of the main components that determine the lifetime of CANDU reactors is the zirconium-alloy pressure tubes that contain fuel bundles and separate the hot water coolant from the cold moderator. During operation, hydrogen from hot water diffuses towards the flaws induced in the tube and with time, forms a brittle phase called zirconium hydrides. To ensure the integrity of the tubes and safety of the reactors, it is important to show that a crack will not nucleate in these hydrides. This project focuses on using advanced numerical techniques and diffraction-based experiments to understand how the hydrides that form in the vicinity of flaws will crack and how such cracks lead to failure. Finite element models will be developed and used at Western University, and with the help of graduate students, experiments will be done at Canadian Nuclear Laboratories to study formation of cracks at nano and meso-scales. This will help understand the underlying mechanisms that control fracture of hydrides.The results from this research are expected to help improve the accuracy of the models used in nuclear industry and improve the lifetime of the pressure tubes used in the core of CANDU reactors.

CANDU反应堆在为安大略和加拿大提供清洁能源方面做出了重大贡献。安大略50%以上的电力是由CANDU反应堆产生的。大部分CANDU反应堆建于20世纪70年代和80年代，正在老化。为了继续运行这些反应堆，工程师必须向监管机构证明它们是安全的。决定CANDU反应堆寿命的主要部件之一是锆合金压力管，它包含燃料棒束并将热水冷却剂与冷慢化剂分开。在运行过程中，来自热水的氢向管中产生的缺陷扩散，随着时间的推移，形成称为锆氧化物的脆性相。为了确保管道的完整性和反应堆的安全，重要的是要表明裂纹不会在这些管道中成核。该项目的重点是使用先进的数值技术和基于衍射的实验，以了解在缺陷附近形成的裂纹如何破裂以及这种裂纹如何导致故障。有限元模型将在西部大学开发和使用，并在研究生的帮助下，将在加拿大核实验室进行实验，研究纳米和中尺度裂纹的形成。这将有助于了解控制断裂的基本机制，从这项研究的结果，预计将有助于提高在核工业中使用的模型的准确性，并提高在CANDU反应堆堆芯中使用的压力管的寿命。