Materials Chemistry Applications that Support the Nuclear Industry

这项拟议的研究旨在支持核工业在应用热力学、高温材料化学和高温下的水化学等领域的研究。已经确定，存在与燃料循环的所有方面有关的材料化学问题，从加工黄饼、设计新燃料、下一代核反应堆，到乏燃料的废物处理。虽然在开发热力学模型来描述燃料在各种环境(即气态、水相)中的行为方面取得了进展，但随着21世纪对生产对环境负责的形式的能源的需求的增加，找到解决这些问题的办法是至关重要的。*高温材料的基本工具之一是相图和相图评估。拟议的研究将建立在主要研究人员将热力学相图建模应用于感兴趣的系统的背景之上。PI之前的工作已经模拟了各种已知在燃烧的燃料中形成的金属合金系统。众所周知，Pd-Sn-Sb-Te四元系和Pd-Ag-Cd三元系在事故场景中是重要的：热传递回路中的气溶胶中的四元系和带有控制棒的三元系。此外，还有其他金属合金系统可能适合作为下一代反应堆的液体冷却剂。*在拟议的新燃料领域，碳化铀和氮化物显示出潜力，但没有像UO2那样得到很好的理解。此外，用钍取代铀(或同时使用两者)可能会令人感兴趣。了解这些系统的行为是将它们开发成燃料的第一步，在考虑事故情况时也很重要。*正在提出一种多年和多方面的方法，安大略大学理工学院正在使用X射线衍射(XRD)、差热分析(DTA)和其他方法进行持续的实验工作。作为PI和CNL，与加拿大核实验室(粉笔河)的持续合作有着悠久的历史。在国际上，国际和平研究所与欧洲的主要研究机构(如CEA、ITU和IRSN)建立了联系。这使得有可能与这些伙伴一起在共同感兴趣的领域开展试验性工作。*与UOIT的同事合作，计划对拟议的燃料处置方法进行研究。燃料模型虽然是为高温行为而开发的，但也可以适用于水环境(如储存舱)或拟议的地下埋藏环境。这项工作也有助于研究各种核应用中的腐蚀。总之，这项工作将加强在UOIT(或其他地方)进行的实验工作与随后可以开发的热力学和热化学模型之间的联系。

The proposed research is intended to support the nuclear industry in the research areas of applied thermodynamics, high temperature materials chemistry, and aqueous chemistry at elevated temperatures. It has been established that there are material chemistry issues related to all aspects of the fuel cycle, from processing yellow cake, design of new fuel, the next generation of nuclear reactors, and waste disposal of spent fuel. While progress has been made to develop thermodynamic models for describing the behaviour of fuel in various environments (i.e., gaseous, aqueous) issues remain, and as the need to produce environmentally responsible forms of energy increases in the 21st century, it is essential that solutions to these issues be found.***One of the basic tools for high temperature materials is the phase diagram and phase diagram evaluation. The proposed research will build on the primary investigator's background in applying thermodynamic phase diagram modelling to systems of interest. Previous work by the PI has modelled various metallic alloy systems known to form in burned up fuel. The quaternary system of Pd-Sn-Sb-Te and the ternary Pd-Ag-Cd are known to be important during accident scenarios: the quaternary in aerosols in the heat transfer circuit and the ternary with the control rods. As well, there are other metallic alloy systems that may be suitable liquid coolants in the next generation of reactors.***In the area of proposed new fuels, uranium carbides and nitrides show potential, but are not as well understood as UO2. Further, replacing uranium with thorium (or using both together) may be of interest. Understanding how these systems behave is the first step in developing them into fuel, and is important in considering accident scenarios.***A multi-year and multi-faceted approach is being proposed, continuing experimental work being performed at the University of Ontario Institute of Technology using X-ray Diffraction (XRD), Differential Thermal Analysis (DTA), and other methods. Continuing collaborations with the Canadian Nuclear Labs (Chalk River) as the PI and CNL have a long standing history. Internationally, the PI has developed links to the major research institutions in Europe (e.g., CEA, ITU, and IRSN). This has allowed for the potential to do experimental work in conjunction with these partners in areas of mutual interest.***In collaboration with colleagues at UOIT, studies of proposed disposal methods for fuel are planned. The models for fuel, while developed for high temperature behaviour can be adapted to an aqueous environment (e.g., storage bays) or proposed environments for underground burial. The work also lends itself to studying corrosion in various nuclear applications. In conclusion, this work will strengthen the links between experimental work performed at UOIT (or elsewhere) and the thermodynamic and thermochemical models that can be subsequently developed.**