Advanced chemistry and corrosion studies under hot water conditions relevant to LWR coolant

该学生将在NNL的Tomas Martin博士、Oliver Payton博士和Rob Burrows博士的指导下，使用先进的材料表征来研究核反应堆钢的热水腐蚀。从欣克利角C核电站开始，英国的下一代核反应堆将不再采用英国特有的气冷设计，而是采用其他核电国家更常见的水冷式反应堆。这些轻水反应堆（LWR）将有明显不同的组件和运行设计，因此这些组件的腐蚀、应力和疲劳机制将与英国工业界和学术界目前研究的组件有很大不同。类似的加压水冷却系统将用于核聚变反应堆，如ITER和DEMO，并且将有许多相同的腐蚀问题。这个博士项目将研究在沸水反应堆（BWRs）的冷却剂中添加贵金属的影响，例如英国威尔法和奥尔德伯里的沸水反应堆。沸水堆存在应力腐蚀开裂（SCC）的历史问题，即水冷剂的腐蚀导致部件在机械应力下开裂。在美国，通过改变冷却水的化学性质，向水中注入氢、锌和铂来减少辐射分解的影响，并限制自由基的种类，可以缓解这个问题。虽然这些物质的加入已被证实有助于防止运行反应堆中应力腐蚀裂缝的增长，但在调试和测试期间，对新反应堆的水化学变化的调查却很少。该项目将与NNL合作开发一个高压灭菌器测试设备，并将一系列钢和镍合金暴露于LWR的水条件和各种水化学物质中，以更好地了解腐蚀背后的机制以及贵金属注入对其的抑制作用。这些样品将采用广泛的最先进的表面和材料分析技术进行表征，包括电子显微镜、电子背散射衍射、x射线衍射和聚焦离子束铣削。通过创建应力材料的小悬臂，将使用高分辨率化学作图工具（如透射电子显微镜和原子探针断层扫描）探索局部SCC的影响。除了使用高压灭菌器腐蚀实验的主要研究工作外，该项目还将在纳米尺度上使用NanoESCA的工作函数电子映射以及在液体电池中使用高速原子力显微镜进行腐蚀的实时成像来探测腐蚀的机制。

This student will be investigating hot water corrosion of nuclear reactor steels using advanced materials characterisation, under the supervision of Dr Tomas Martin, Dr Oliver Payton and Dr Rob Burrows of NNL. The next generation of nuclear reactors in the UK, beginning with Hinckley Point C, will eschew the UK-specific gas-cooled design for the water-cooled type of reactor more commonly found in other countries with nuclear power. These light water reactors (LWR) will have significantly different components and operational design, and as such the mechanisms of corrosion, stress and fatigue in these components will be dramatically different from those currently studied in UK industry and academia. Similar pressurised water cooling systems will be used for fusion reactors such as ITER and DEMO, and will have many of the same corrosion issues.This PhD project will investigate the effects of noble-metal addition to the coolant of Boiling Water Reactors (BWRs) such as those proposed at Wylfa and Oldbury in the UK. BWRs have had a historical issue with stress corrosion cracking (SCC), where corrosion from the water coolant results in cracking of components under mechanical stress. In the USA, this problem is mitigated by changing the coolant water chemistry, injecting hydrogen, zinc and platinum to the water to reduce the effect of radiolysis and limit free radical species. Whilst the addition of these species has been confirmed to help prevent the growth of stress corrosion cracks in operational reactors, there has been little investigation of this changed water chemistry on new reactors during commissioning and testing, and on the The project will develop an autoclave testing facility in partnership with NNL and expose a series of steel and nickel alloys to LWR water conditions and a variety of water chemistries to better understand the mechanism behind corrosion and its inhibition by noble metal injection. These specimens will be characterised with a wide range of state-of-the-art surface and materials analysis techniques, including electron microscopy, electron backscatter diffraction, X-ray diffraction and focused ion beam milling. By creating small cantilevers of stressed material, the effect of localised SCC will be explored using high resolution chemistry mapping tools such as transmission electron microscopy and atom probe tomography. In addition to the main research work using autoclave corrosion experiments, the project will probe the mechanism of corrosion at the nanoscale using electronic mapping of the workfunction using the NanoESCA combined with live imaging of corrosion using high-speed atomic force microscopy in a liquid cell.