A whole-life approach to the development of high integrity welding technologies for Generation IV fast reactors

“焊接模型”是了解焊接结构性能的有力工具。传统的基于连续介质力学的焊接应力预测已经在理解英国核反应堆船队中焊缝的使用性能和退化机制方面取得了相当大的成功。然而，目前它们的实际应用仅限于在焊接过程中不发生所谓的固态相变(SSPT)的材料，因为SSPT的存在使得有必要预测材料微观结构的变化以预测应力。此外，焊接引起的微观组织变化对焊缝的蠕变、热老化、氧化、应力腐蚀和其他在役退化机制以及对裂纹存在的敏感性具有深远的影响。联谊会研究计划旨在将传统的焊接模型扩展为一种多学科工具，既可以预测连续介质参数(如应力和变形)，也可以预测微观结构参数(如晶粒度和形状、第二相的出现和析出物的分布)，因此既可以直接预测长期结构性能，也可以用于焊接工艺和新焊接工艺过程的虚拟样机。无论是在英国现有的核反应堆船队，还是在焊缝的长期结构性能非常重要的任何工业部门，成功都提供了更好地了解焊缝使用性能的前景。它还将帮助选择焊接件材料、接头设计和焊接工艺，用于新建核电站的结构焊缝，以及可能建立在更长时间框架上的先进的第四代设计。

"Weld modelling" is a powerful tool in understanding the structural performance of welded structures. Conventional continuum-mechanics-based predictions of the stresses generated by welding have achieved considerable success in understanding the in-service performance and degradation mechanisms of welds in the UK's nuclear reactor fleet. However their practical use is currently limited to materials that do not undergo so-called solid state phase transformation (SSPT) during welding, since the presence of SSPT makes it necessary to predict changes in the material microstructure in order to predict the stresses. In addition, the microstructural changes imposed by welding have a profound influence on a weld's resistance to creep, thermal ageing, oxidation, stress corrosion and other in-service degradation mechanisms, and upon its sensitivity to the presence of cracking.The Fellowship research programme aims to extend conventional weld modelling into a multi-disciplinary tool that can predict both continuum parameters such as stress & distortion, and microstructural parameters such as grain size and shape, the occurrence of secondary phases, and precipitate distributions, and hence both directly predict long term structural performance and be used for "virtual prototyping " of weld processes and procedures for novel welding processes. Success offers the prospect of better understanding of in-service performance of welds in both the existing UK nuclear reactor fleet, and in any industrial sector where the long term structural performance of welds is important. It will also aid the choice of weldment materials, joint design and welding process for structural welds in new-build nuclear power plants, and in advanced Generation IV designs that may be built on a longer time frame.