FaSCiNATe: Facility for the Structural Characterisation of materials for Nuclear Applications operating at high Temperatures

FaSCiNATe将提供一套独特的、互补的科学仪器，以验证中子辐照材料中微观结构损伤的热稳定性以及对机械性能的相关影响。为了延长现有核反应堆的寿命，提高燃料组件的安全性和运行效率，以及为未来设计更高效的反应堆，需要能够预测材料在辐照下的降解。目前正在研究新材料，使未来的反应堆能够在更高的温度下运行，从而提高效率。然而，为了了解反应堆内部材料特性的变化，需要在这些更高的温度下对中子辐照样品进行测试。该项目中的仪器将提供高温下的性能信息和微结构变化，以便更好地了解导致性能下降的潜在机制。这将有助于改进材料，使其能够科普未来反应堆系统的高辐射剂量和高温环境。在英国原子能机构的材料研究设施（MRF），由于受到中子或高能质子照射而具有放射性的材料可以在提供屏蔽的环境中进行处理和分析，以保护工作人员免受照射。将实施另外三种补充科学技术，以测量材料微观结构的变化及其对热性能和机械性能的影响：差示扫描量热法，高温X射线衍射和高温下的原位微米级机械测试。这些科学仪器将被整合到屏蔽环境中，并配备自动样品安装系统，以便将放射性样品远程插入分析设备并从中取出。通过研究材料在微米尺度上的变形，可以推导出辐照如何影响基本的变形机制。安装在电子显微镜内部的原位加载框架将允许观察材料在工作温度下的变形，以推断通过改进材料设计来防止严重损伤累积的方法。加热有缺陷的材料将导致原子重新排列，从而修复一些损伤，从而释放能量。根据缺陷和材料的不同，这种能量可能很小，需要灵敏的设备来检测。高真空差示扫描量热法可以准确地检测能量随温度的变化，从而测量辐照材料中储存的能量。相变也会释放或吸收能量，因此辐照诱导的相变也可以通过这种技术进行量化。由于辐照缺陷团簇的存在而引起的原子位置的细微变化可以通过高灵敏度的X射线衍射技术进行非破坏性检测。在此应用中提出的改进将允许原位加热的标本，从而揭示了随着温度的升高恢复的损伤的演变，照亮可能的策略，以消除损伤和基本的information.The这些技术的组合提供了一个全面的表征微观结构损伤的统计方式，补充当地的详细表征使用透射电子显微镜。这将使中子和质子辐照样品的材料研究能够用于广泛的高影响力研究课题，包括：安全关键部件的结构完整性，燃料包壳降解机制，通过反应堆压力容器退火延长寿命，以及为未来反应堆系统开发新材料，第四代裂变和聚变，在更高的温度和更高的剂量下运行。

FaSCiNATe will provide a unique and complementary suite of scientific instruments to characterise the thermal stability of microstructural damage in neutron irradiated materials and the associated effects on mechanical properties. Being able to predict materials degradation under irradiation is required for life-time extension of existing nuclear reactors, improving safety and operational efficiencies of fuel assemblies and for designing more efficient reactors for the future. Research is ongoing on new materials that would enable future reactors to operate at higher temperatures and therefore be more efficient. However, to understand how material properties change inside reactors, tests on neutron irradiated samples need to be done at these higher temperatures. The instruments in this project will give performance information at high temperatures and characterise microstructural changes so that underlying mechanisms causing performance degradation can be better understood. This will allow to improve materials to be able to cope in the high radiation dose and high temperature environment of future reactor systems.At UKAEA's Materials Research Facility (MRF), materials that have become radioactive by being subjected to neutron or high energy proton irradiation, can be processed and analysed in an environment that provides shielding to protect staff from exposure. Three additional complementary scientific techniques will be implemented to measure changes in the materials' microstructure and the resulting impact on their thermal and mechanical properties: differential scanning calorimetry, high temperature X-ray diffraction and in-situ micron-scale mechanical testing at high temperature. These scientific instruments will be integrated in shielded environments and equipped with robotic sample mounting systems to remotely insert and retrieve radioactive samples into the analysis equipment.Neutron irradiation damage often affects mechanical behaviour of components under load. By studying material deformation at the micron-scale, it can be derived how irradiation affects the fundamental deformation mechanisms. The in-situ load frame mounted inside an electron microscope will allow to observe materials deform at operational temperatures to infer ways to prevent the accumulation of serious damage by improved material design.Heating defective materials will cause atoms to rearrange and therefore heal some of the damage, thus releasing energy. Depending on the defects and the material, this energy can be small and needs sensitive equipment to detect it. A high-vacuum differential scanning calorimetry can accurately sense the change in energy as a function of temperature and therefore measure the amount of energy stored in irradiated materials. Phase changes also release or absorb energy, so irradiation-induced phases can also be quantified with this technique.Subtle changes in atomic positions, caused by the presence of irradiation defect clusters can be detected non-destructively using the highly-sensitive technique of X-ray diffraction. Improvements proposed in this application will allow in-situ heating of the specimen, thus revealing the evolution of the damage as it recovers with increasing temperature, illuminating possible strategies for removing damage and fundamental information.The combination of these techniques provides a comprehensive characterisation of microstructural damage in a statistical way, complementing local detailed characterisations using transmission electron microscopy. This will enable materials research on neutron and proton irradiated samples for a wide range of high-impact research topics including: structural integrity of safety critical components, mechanisms of fuel cladding degradation, lifetime extension through annealing of the reactor pressure vessel and development of new materials for future reactor systems, Gen-IV fission & fusion, which operate at higher temperatures and higher doses.