Improving the Performance of Advanced Technology Fuels

核燃料设计变革的动力是向事故容忍度发展，特别是与冷却剂高温包层氧化的缺失或延迟有关。任何UO2燃料的替代品都必须提供更安全的操作和更低的燃料循环成本；要么长周期，要么低富集。目前的候选材料是单氮化铀（UN），它提供了这些特性的最大组合，并具有工业规模化的潜力。然而，这种水有一个主要的性能缺陷，更重要的是，在运行期间，高T水/蒸汽对UN的腐蚀性明显大于目前在水慢化反应堆中使用的UO2氧化物燃料。拟议的博士项目将专门解决驱动事故耐受性燃料（ATF）研究的两个关键问题：导热性退化和腐蚀行为，主要关注燃料-水相互作用。这种相互作用将与燃料生命周期的三个关键阶段，在operando（高温水/蒸汽），在临时储存和在长期废物储存情况下进行探讨。该项目将需要合成大块和薄膜样品；多晶和单晶，使用特高压气体钻机和专用的锕系元素直流磁控溅射系统。表征将使用一系列表面分析技术进行，特别强调利用x射线衍射（XRD）和x射线光电子能谱（XPS）。我们将利用布里斯托尔牛津核研究中心（NRC），并使用牛津TEM套件在原子尺度上研究燃料表面。博士学位是目前英国核裂变研究和发展的前沿。它将研究改善燃料水性能的潜在途径，包括掺杂剂和表面涂层，对可能的选择进行全面审查

The drive for change in nuclear fuel design is towards accident tolerance, which specifically relates to the absence or delay of high-temperature clad oxidation by coolant. Any replacement for UO2 fuel must offer a combination of safer operation with lower fuel cycle cost; either longer cycles or lower enrichment. The candidate material that offers the greatest combination of these properties with the potential for industrial scale-up is currently uranium mononitride, UN. However, there is a major behavioural draw-back in that water, and more importantly during operation, high T water/steam, is significantly more corrosive to UN than the UO2 oxide fuel currently employed in water moderated reactors.The proposed PhD project will specifically address the two key issues that are driving research of accident tolerant fuels (ATF): thermal conductivity degradation and corrosion behaviour, with the main focus on the fuel-water interaction. This interaction will be explored with relation to three key stages of the fuel life cycle, in operando (high temperature water/steam), in interim storage and in long-term waste storage scenarios. The project will require synthesis of both bulk and thin film samples; polycrystalline and single crystals, using UHV gas rigs and a dedicated actinide dc magnetron sputter system. Characterisation will be conducted using a range of surface analysis techniques, with particular emphasis on utilising x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS). We will make use of the Bristol Oxford Nuclear Research Centre (NRC) and employ the Oxford TEM suite to investigate the fuel surfaces on an atomic scale.The PhD is at the forefront of current UK research and development in nuclear fission. It will investigate potential avenues for improving fuel-water performance, including dopants and surface coatings, providing a comprehensive review of possible options