Liquid lithium corrosion for nuclear fusion

未来核聚变装置的包层模块可能会有一种冷却剂，不仅可以冷却反应堆，还可以产生氚，这种燃料用于等离子体中。这可以是PbLi共晶或纯锂。PbLi由于其增殖中子（Pb）和增殖氚（Li）的能力而被广泛研究。然而，PbLi不会像纯锂那样产生那么多的氚。虽然使用锂离子电池的腐蚀测试很多，但使用液态锂的测试却少得多。20世纪70年代的报告表明，难熔金属在液态锂中的相容性比其他金属好，而日本最近的研究表明，氧化铒可能是一种潜在的涂层。我们在牛津开发了一个定制的液态锂测试平台，可以在静态锂和PbLi的温度范围内进行测试。为了了解这些涂层对环境的耐受性，在Li中进行了初步测试，以了解化学相容性。然而，由于全球缺乏测试设备，了解液态锂和辐照的协同效应的测试既困难又昂贵。因此，Li和辐照环境中的试验通常是随后进行的，而不是同时进行的。该项目将使用国家离子束中心的质子辐照和新建立的牛津测试设施的PbLi和Li腐蚀的组合，以了解在这些条件下可能发生的协同效应。降解过程的表征将使用分析电子显微镜，包括STEM-EDX， SEM-TKD和FIB-SEM断层扫描。涂层的粘合性能将使用牛津大学开发的划痕测试方法来测量，以了解界面破坏机制。显微结构和力学表征的结果将用于设计合金化学或涂层组合，以提高抗降解和脱粘的能力。作为该项目的一部分，腐蚀设施的进一步发展将包括在液态锂坩埚内集成搅拌和氧位传感器。该项目可能会得到中小企业的工业支持。

The blanket module of the fusion devices of the future is likely to have a coolant, that not only cools the reactor, but breeds tritium, the fuel that is used within the plasma. This can either be PbLi eutectic or pure lithium. PbLi has been extensively studied due to its ability to multiply neutrons (Pb) and breed tritium (Li). However PbLi does not breed as much tritium as a pure lithium. Whilst there has been much corrosion testing using PbLi there has been much less using liquid lithium. Reports form the 1970's suggest refractory metals have better compatibility in liquid lithium than other metals and more recent work in Japan suggest erbium oxide maybe be a potential coating. We have developed a bespoke liquid lithium testing rig in Oxford to allow testing at a range of temperatures in static Li and PbLi. To understand the tolerance of these coatings with the environment, preliminary tests in Li have been performed to understand the chemical compatibility. However, tests to understand the synergistic effects of liquid lithium and irradiation are difficulty and costly as there is a lack of testing equipment globally. So, tests in Li and irradiation environments are usually done subsequently, rather than concurrently.This project will use a combination of proton irradiation at the National Ion Beam Centre and PbLi and Li corrosion at the new established Oxford testing facility to understand synergistic effects that may occur under these conditions.Characterisation of the degradation process will use analytical electron microscopy including STEM-EDX, SEM-TKD and FIB-SEM tomography. Adhesive properties of the coatings will be measured using scratch testing methods developed in Oxford to understand interfacial failure mechanisms. The results from the microstructural and mechanical characterisation will be used to either engineer the alloy chemistry or coating combinations to improve the resistance to degradation and decohesion. Further development of the corrosion facilities as part of the project will include integration of the stirring within the liquid lithium crucible and oxygen level sensors. There is likely to be industrial support from a SME to this project.