Welded joints behaviour in high temperature reactors

焊接接头是反应堆结构中最关键的安全部位之一。它们在运行了几十年后往往容易损坏，可以被认为是英国先进的气冷反应堆的寿命限制因素之一。这是因为焊接过程复杂，包括残余应力、不同的显微组织及其复杂的几何形状。该项目的目的是通过先进的实验技术，如数字图像相关和同步辐射X射线衍射，确定在焊接接头界面产生的应力集中的临界点。实验工作预计将得到有限元模拟的补充，以评估在焊接界面累积的蠕变损伤的严重程度。关键的是，关键结果预计将包括在工程师日常使用的完整性评估程序中，以评估反应堆部件的服务适宜性。

Welded joints are one of most safety critical locations in a reactor structure. They are often prone to damage after decades of operation and can be considered to be one of the life-limiting factors in the UK's advanced gas cooled reactors. This is because of the complexities involved in a weld including the residuals stress, varying microstructure and their complicated geometry. The aim of this project is to identify the criticality of the stress concentration created at the interface of a welded joint through advanced experimental techniques such as Digital Image Correlation and synchrotron X-ray diffraction. The experimental work is expected to be complemented by finite element simulations to assess the severity of the creep damage accumulated at the weld interface. Critically, the key results are expected to be included in the integrity assessment procedures the engineers use day to day to evaluate the fitness for service of reactor components.