Modelling of Primary Water Stress Corrosion Cracking (PWSCC) of Nickel Based Alloys (NBAs) in Nuclear (PWR) Primary Coolant

与传统的钢材料相比，镍基合金材料及其相关的焊接金属具有优越的结构性能，因此在新建和先进的核反应堆中备受关注。它们已经在美国压水堆反应堆中实施，注意到对材料的要求能够抵抗苛刻的环境条件，运行周期约为60至80年。在压水堆的一次回路中，结构材料在高压水环境中承受高温。因此，一些NBAs显示出对初级水应力腐蚀开裂（PWSCC）的敏感性，这已经被Wood plc进行的PWSCC实验室测试项目所证实。虽然材料内的应变水平显然对PWSCC有重大影响，但对增加PWSCC敏感性因素的机理理解有限。因此，建议采用连续介质力学建模方法来理解在PWSCC测试期间这些材料内部的损伤积累。这种方法可以扩展到理解母材、焊缝和相关热影响区的复合焊缝试样测试中涉及的更复杂的行为

Nickel Based Alloy (NBA) materials and their associated weld metals are of interest to new build and advanced nuclear reactors due to their superior structural performance when compared with traditional steel materials. They are already implemented in US PWR reactors, noting the requirement for materials resistant to demanding environmental conditions for operating periods of ~60 to 80 years. Within the primary circuit of a PWR, structural materials are subjected to elevated temperatures in a high pressure water environment. As a result, some NBAs have shown susceptibility to Primary Water Stress Corrosion Cracking (PWSCC), and this has been confirmed by a significant programme of PWSCC laboratory testing conducted by Wood plc. Whilst it is apparent that strain levels within a material have a significant impact on PWSCC, mechanistic understanding of factors that increase PWSCC susceptibility is limited. Therefore, it is proposed that a continuum mechanics modelling approach is applied to understand the damage build-up within these materials during a PWSCC test. This approach can be extended to understand the more complex behaviour involved in testing of composite weld specimens of parent material, weld and associated heat affected zone