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

镍基合金（NBA）材料及其焊缝金属由于其上级结构性能优于传统钢材而受到新建和先进核反应堆的关注。它们已经在美国PWR反应堆中实施，并注意到对材料的要求，这些材料能够耐受约60至80年的运行期的苛刻环境条件。在PWR的主回路内，结构材料在高压水环境中经受高温。因此，一些NBA显示出对一回路水应力腐蚀开裂（PWSCC）的敏感性，这一点已被Wood plc进行的PWSCC实验室测试的重要计划所证实。虽然很明显，材料内的应变水平对PWSCC有显著影响，但对增加PWSCC敏感性的因素的机械理解是有限的。因此，建议采用连续介质力学建模方法来了解PWSCC试验期间这些材料内的损伤累积。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试验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