Modelling radiation resistant low activation High Entropy Alloys

英国政府的政策是，核能在提供安全、低碳、废物产生最少的能源未来方面发挥着重要作用；例如，政府今年夏天发布的“核能行业协议”文件将“创新主导增长的长期愿景作为优先事项，该愿景将不断降低发电成本，并为纳税人减少20%的退役成本”。2018年，英国约20%的电力来自核反应堆，很可能对电能的需求只会增加，例如通过运输电气化。在短期内，小型模块化反应堆（SMR）和第三代技术可以用来满足需求。用于下一代核反应堆的抗辐射合金的开发将有助于维持和扩大英国建造先进发电厂的能力，并有能力提供可靠的低碳能源。随着2016年EPSRC裂变和聚变独立审查中材料科学被强调为关键挑战，该项目将旨在利用先进的计算机建模和仿真来解决功能材料的挑战。因此，在这个项目中，原子模型高熵合金（HEAs）将被开发，并用于研究特定低活化HEAs的机械和热性能（即它们在长时间内不会变成高放射性）。HEAs是一种新型合金，其中没有单一金属元素占主导地位，四种或四种以上元素以接近相等的原子比使用。HEAs目前是一个重要的国际研究课题，因为与传统合金相比，HEAs具有优异的机械性能，如优异的硬度、高温强度和稳定性。因此，只要它们在辐照下不发生活性，它们在核应用方面具有极好的潜力。基于从头算技术的各种理论模型将被实施来研究机械和热性能，并将这些与实验进行比较。然而，由于计算限制，使用从头算方法可以研究的系统规模必然很小，因此该项目的第二个目标是通过将从头算结果与经典势形式主义联系起来，通过使用多尺度建模来研究更大的系统。这将允许合金在辐照下的行为进行研究，并将结果与其他更传统的材料进行比较。该项目将集中研究低活化HEAs，特别是由TiVZrTa、VWMoCr和TiVCrMnFe组成的HEAs，这将在相关的实验方案中考虑，但将开发和使用的技术将普遍应用于其他复杂合金，因此可能广泛应用于核领域以外的领域。

The UK Government policy is that nuclear energy has an important role to play in providing an energy future that is safe and low carbon with minimal waste production; for example, the Government's "Nuclear Sector Deal" paper published this summer has as a priority "a long-term vision of innovation-led growth that delivers successively lower generation costs and a 20% reduction in decommissioning costs to the taxpayer".In 2018, the UK derived ~20% of its electrical power from nuclear reactors and it is likely that demand for electrical energy will only increase, e.g., through the electrification of transport. In the short term, small-modular reactors (SMR) and Gen-III technologies may be utilised to meet demand. The development of radiation-resistant alloys for use in next-generation nuclear reactors will help sustain and expand the UK's capacity to build advanced power plants, with the ability to deliver reliable low-carbon energy. With Materials science highlighted as the key challenge in the 2016 EPSRC Independent Review of Fission and Fusion, this project will aim at addressing the functional materials challenge using advanced computer modelling and simulation.Therefore in this project, atomistic models High Entropy Alloys (HEAs) will be developed and the models used to investigate the mechanical and thermal properties of specific low activation (i.e. they do not become highly radioactive for long periods) HEAs. HEAs are novel alloys where no single metallic element dominates and four or more elements are used in near equal atomic ratios. HEAs are currently the subject of a significant international research effort due to their reported superior mechanical properties compared to conventional alloys, such as excellent hardness and high temperature strength and stability. They have therefore excellent potential for nuclear applications provided they do not become active under irradiation.Various theoretical models based on ab initio techniques will be implemented to investigate mechanical and thermal properties and these will be compared to experiment. However the system sizes that can be studied using ab initio methods are necessarily small due to computing limitations and so a second aim of the project is to study larger systems through the use of multi scale modelling by linking the ab initio results with a classical potential formalism. This will allow the alloy behaviour under irradiation also to be investigated and the results compared with other more conventional materials.The project will concentrate on the investigation of reduced activation HEAs specifically those comprising of TiVZrTa and VWMoCr and TiVCrMnFe, which will be considered in a related experimental programme but the techniques that will be developed and used will have a general application to other complex alloys and therefore potentially wide use outside the nuclear area.