High Temperature Zirconium Alloys for Nuclear Fusion and Generation IV Fission Reactors

这项研究将开发未来核聚变和第四代裂变反应堆所需的新的锆基材料，这些材料可以用零或减少的长寿命核废料产生无碳能源。这项工作将与库勒姆聚变能源中心(CCFE)和劳斯莱斯合作进行，合作范围包括曼彻斯特、牛津、帝国理工学院、班戈、法兰克福DECHEMA和ANSTO Sydne.核能是我们摆脱化石燃料及其大规模二氧化碳排放的能源组合中的关键部分。然而，对长寿放射性废物、安全和成本的担忧阻碍了核能的发展。未来先进的核反应堆概念解决了这些担忧。核聚变不会产生如此长寿命的放射性废物，而且本质上是安全的，不可能发生失控的反应。下一代IV裂变反应堆提高了效率和容量，显著降低了燃料使用量和成本，同时本质上是安全的。对于聚变和裂变，除了等离子体物理和反应堆工程方面的挑战外，还需要超出当前能力的先进材料。该计划开发的先进材料将设计为在聚变和下一代裂变反应堆所需的高工作温度下保持稳定。1950-70年开发的锆合金在目前的裂变反应堆中表现出色，因为它们具有低的中子截面积和耐腐蚀性，在中等温度(~330℃)下具有足够的强度。然而，聚变和第四代裂变的运行温度要高得多(500-800摄氏度)，这与它们的先进冷却剂有关：液态金属、氦气或熔盐。目前的高温合金缺乏高温强度，这就需要本项目开发新的高温合金。针对高温钛合金开发的合金设计方法，通过80‘S和90’S，将扩展到锆合金，利用它们共同的晶体结构。强度将通过(1)结构细化和(2)高强度金属间化合物增强而获得。人们将关注用于产生这种机械性能改善的硅、铝和铬的添加是否也能提高环境对氧化、腐蚀或辐射损伤的韧性。第二种合金设计策略将采用局部高熵合金(HEA)方法，这是最近迅速发展的材料科学领域。我们将在我们最近对ZrTiVNb HEA系统(https://doi.org/10.1016/j.actamat.2019.01.006)，到ZrTiVTa和ZrTiV(Nb/Ta)X(X=Cr，Si，Al)HEA系统的概念验证研究的基础上，开展工作来表征锆基HEA。该项目将帮助英国保持在聚变和第四代裂变研究的前沿，并确立英国在快速发展的HEA领域的存在，目前英国在该领域的代表不足。

This research will develop new zirconium-based materials needed for future nuclear fusion and generation IV fission reactors, which allow carbon-free energy generation with nil or reduced long-lived nuclear-waste. The work will be carried out in partnership with Culham Centre for Fusion Energy (CCFE) and Rolls-Royce, with collaborations across Manchester, Oxford, Imperial College, Bangor, DECHEMA Frankfurt and ANSTO Sydney.Nuclear power is a key part of the energy mix in our transition away from fossil fuels and their large-scale emission of carbon dioxide. However, nuclear is held back by concerns over long-lived radioactive waste, safety and cost. Future advanced nuclear reactor concepts address these concerns. Nuclear fusion produces no such long-lived radioactive waste and is inherently safe with a runaway reaction impossible. Next Generation IV fission reactors have increased efficiency and capacity for significantly reduced fuel usage and cost whilst being intrinsically safe. For both fusion and fission, in addition to plasma physics and reactor engineering challenges, there is a need for advanced materials that are beyond current capabilities.The advanced materials developed in this programme will be designed for stability at the high operating temperatures required for fusion and next-generation fission reactors. Zirconium alloys developed 1950-70 excel in current fission reactors, owing to their low neutron cross section and corrosion resistance, with adequate strength at moderate temperatures (~330 degrees C). However, fusion and Gen IV fission operate at much higher temperatures (500-800 degrees C) associated with their advanced coolants: liquid metal, helium gas or molten salt. The current Zr alloys lack high temperature strength, necessitating this project's development of new high temperature Zr alloys.Alloy design approaches that were developed for high temperature Ti alloys, through the 80's and 90's, will be extended to Zr, exploiting their common crystal structure. Strength will be gained (1) by structural refinement and (2) by reinforcement with high strength intermetallic compounds. Attention will be made to see whether Si, Al and Cr additions employed to generate such mechanical property improvements also promote environmental resilience against oxidation, corrosion or irradiation damage. A second alloy design strategy will employ the topical high entropy alloy (HEA) approach, which is a recent and rapidly growing field of materials science. Work will be undertaken to characterise zirconium-based HEAs, building from our recent proof of concept study on the ZrTiVNb HEA system (https://doi.org/10.1016/j.actamat.2019.01.006), to ZrTiVTa and ZrTiV(Nb/Ta)X (X = Cr, Si, Al) HEA systems. These have the potential to further increase high temperature mechanical properties and environmental resistance.This project will help to keep the UK at the cutting edge of fusion and Gen IV fission research, as well as establishing the UK's presence in the rapidly developing HEA field, where it is currently underrepresented.