Liquid lithium corrosion for nuclear fusion

未来聚变装置的包层模块可能会有一个冷却剂，它不仅能冷却反应堆，还能产生氚，氚是等离子体中使用的燃料。这可以是PbLi共晶，也可以是纯锂。PbLi由于具有倍增中子(Pb)和产生氚(Li)的能力而被广泛研究。然而，PbLi产生的氚不像纯锂那么多。虽然已经有很多使用PbLi的腐蚀测试，但使用液态锂的测试要少得多。20世纪70年代S的报告表明，难熔金属在液态锂中比其他金属具有更好的相容性，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台定制的液态锂测试台，可以在静态Li和PbLi的温度范围内进行测试。为了了解这些涂层与环境的耐受性，在LI进行了初步测试，以了解化学兼容性。然而，由于全球缺乏测试设备，了解液态锂和辐射的协同效应的测试是困难和昂贵的。因此，在锂和辐照环境中的测试通常是随后进行的，而不是同时进行的。这个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腐蚀来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包括STEM-EDX、SEM-TKD和FIB-SEM断层扫描在内的分析电子显微镜。涂层的附着力将使用牛津大学开发的划痕测试方法进行测量，以了解界面失效机制。微观结构和机械表征的结果将被用于设计合金化学或涂层组合，以提高耐降解性和脱附性。作为该项目的一部分，进一步开发腐蚀设施将包括集成液态锂坩埚内的搅拌和氧气水平传感器。这个项目很可能会得到中小企业的产业支持。

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.