Improving the Performance of Advanced Technology Fuels

改变核燃料设计的动力是事故容忍度，这具体涉及到没有或延迟冷却剂高温包层氧化。任何UO2燃料的替代品必须结合更安全的操作和更低的燃料循环成本；或者更长的循环或更低的浓缩度。目前，将这些特性与工业放大潜力最好地结合在一起的候选材料是联合国的一氮化铀。然而，在这种水中有一个主要的行为回撤，更重要的是，在运行期间，高T水/蒸汽对联合国的腐蚀性明显高于目前水慢化反应堆中使用的UO2氧化物燃料。拟议的PHD项目将具体解决推动事故容忍燃料(ATF)研究的两个关键问题：导热性能下降和腐蚀行为，主要集中在燃料-水相互作用上。将结合燃料生命周期的三个关键阶段来探讨这种相互作用，即在操作区(高温水/蒸汽)、临时储存和长期废物储存情景中。该项目将需要使用特高压气体装置和专用的鳗系元素直流磁控溅射系统，合成块状和薄膜样品；多晶和单晶。将使用一系列表面分析技术进行表征，特别是利用X射线衍射(X射线衍射)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)和牛津电子显微镜套件在原子尺度上研究燃料表面。该博士处于当前英国核裂变研究和发展的前沿。它将调查改善燃料-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