Consideration of Co incorporation behavior in oxide film under advanced boiling water reactor conditions

沸水反应堆（BWRs）在温度高达288C的高纯净水中运行，在饱和蒸汽和压力~70 Bar的水中运行，由于其良好的强度和耐腐蚀性，大多数结构部件和管道由不锈钢制成。然而，当不锈钢在高温水中被腐蚀时，结构材料中的杂质——非放射性的钴59被释放到水中，被活化，变成放射性的Co-60。然后，反应堆冷却水中的Co-60会被掺入沸水堆结构材料的氧化膜中，导致工作人员在检查和维护期间受到辐射。为了减少工人的职业暴露，冷却剂的水化学得到充分控制，新建工厂可能会使用在线NobleChem （OLNC）与氢水化学（HWC）结合在水中注入锌，以减少Co-60的掺入，减轻结构材料的腐蚀行为。然而，对Co在氧化物中掺入的机理还不完全了解。因此，该项目的目的是发展对不同水化学处理对氧化物演变的协同作用的科学理解，以便下一代发电厂的水化学可以得到优化。该项目将在材料性能中心进行，该中心是材料系的一部分，也是曼彻斯特大学核道尔顿研究所的一个中心。该中心在核部件的微观结构表征、冶金、氧化和结构完整性方面拥有广泛的专业知识，并拥有大量最先进的材料表征设施和用于复制核环境的高压灭菌器。成功的候选人将掌握材料性能方面的技能，并精通材料和微观结构表征，包括二次电子显微镜（SEM），聚焦离子束（FIB），透射电子显微镜（TEM）， x射线衍射（XRD）和其他先进的表征技术。

Boiling water reactors (BWRs) operates in high-purity water at temperatures up to 288C in saturated steam and water at pressure ~70 Bar and most structural components and piping are made out of stainless steel thanks to their good strength and corrosion resistance properties. However, when stainless steel corrodes in high temperature water, non-radioactive cobalt 59, which is an impurity in structural materials, is released into the water, gets activated and become radioactive Co-60. This Co-60 in the reactor coolant water can then be incorporated within the oxide film of the structural materials in the BWR and cause workers to be irradiated during inspection and maintenance. To reduce occupational exposure of workers, water chemistry of coolant is adequately controlled and new build plants will probably apply on-line NobleChem (OLNC) with hydrogen water chemistry (HWC) in combination with zinc injection in the water to reduces the Co-60 incorporation and mitigate the corrosive behaviour of structural materials. However the mechanistic understanding of the Co incorporation in the oxide is not fully understood. Therefore the aim of this project is to develop a scientific understanding of the synergisms of different water chemistry treatments on oxide evolution so that the water chemistry of the next generation power plants can be optimized. The project will be carried out at the Materials Performance Centre, part of the Department of Materials and one the centres of the Nuclear Dalton Institute at the University of Manchester. The centre has extensive expertise in microstructural characterization, metallurgy, oxidation, and structural integrity of nuclear components and has a large number of state-of-the-art material characterization facilities and autoclaves for replicating nuclear environments. The successful candidate will acquire skills in materials performance and will become proficient in the materials and microstructural characterization, which include secondary electron microscopy (SEM), focused ion beam (FIB), transmission electron microscopy (TEM), X-ray diffraction (XRD) and other advanced characterization techniques.