COMPREHENSIVE INVESTIGATION OF SELECTED METAL OXIDES WITH APPLICATION FOR CLEAN ENERGY

对选定的金属氧化物及其在清洁能源中的应用进行全面研究

• 批准号: RGPIN-2014-04274
• 负责人: Szpunar, Barbara
• 金额: $ 1.38万
• 依托单位: University of Saskatchewan
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=666349
• 关键词: COMPREHENSIVE; INVESTIGATION; SELECTED; METAL; OXIDES

This proposal concerns the application of multi-scale modeling at both nuclear and atomistic levels. This work is unique because it combines nuclear simulations with materials modeling. Although the techniques to be used are well established, they have never been coupled together as proposed here. This work will apply state of the art, first principles (predictive) and improved modeling to investigate structural, optical, mechanical, and thermo-physical properties of novel and nuclear materials. The overall objective of this research is to develop a fundamental understanding of the properties of novel and nuclear materials. The short-term objectives over the next three years focus on (1) use of combined simulation of the radiation sources and atomistic molecular dynamics modeling of nuclear materials to achieve a better, fundamental understanding of the effects of radiation; (2) use of ab initio, predictive, and semiempirical methods to study the effect of radiation induced defects on the properties of materials on a large scale; (3) determining structural, mechanical, and thermo-physical properties for various nuclear fuels from simulations; (4) investigating optical and electronic properties of actinide oxides (with emphasis on U3O8); and (5) preparing interactive code for a reactor safety course.**The semiconductive properties of uranium oxides are of interest since these oxides have dielectric constants much higher (e ~ 20) than SiO2 (3.5). Depleted uranium oxides can be recovered from nuclear waste and have potential application in solar cells and electronics. They are also a by-product of the production of enriched uranium. U3O8 is the most stable uranium oxide but there are no experimental data available about optical band gap. We have the required expertise to investigate the electronic structure and the band gap of U3O8, both experimentally (at Canadian Light Source) and theoretically. Cameco Inc. in Saskatoon can provide us with samples of depleted U3O8 that can be safely examined. Once the band gap has been determined both the optical and mechanical properties will be accurately determined from first principles calculations. They will be used to evaluate the potential application of U3O8 in solar panels. It will lay the groundwork for new applications for uranium oxides in the province of Saskatchewan beyond the current export of uranium ore. Accurate data on the mechanical and structural properties of U3O8 would allow the prediction of stresses when urania volume increases due to oxidation during an accident in a reactor or waste storage compartment.**We have studied various nuclear fuels theoretically, especially inherently safe thoria with high thermal conductivity that prevents fuel melting by more efficient heat dissipation. However the experimental data for thermal conductivity of fuel show big differences and implications of burn-up-induced degradation is not well known. Monte Carlo code will be used to simulate the atoms displacements in fuels in operating fuel rods and a physical burnup will be evaluated. The parameters in classical molecular dynamics code will be tuned up using the first principles calculations and it will be used to evaluate the degradation of the thermal conductivity by the physical burnup. The comparison between urania and thoria fuel behaviours will be investigated.**The developed thermal conductivity correlations for pure fuel and with inclusion of defects will be used in the new interactive software for multidisciplinary investigation of nuclear reactor safety and investigation of fuel melting in an accident similar to Fukushima. It is critical for the design of safer reactors to have access to new methods of simulating the properties of uranium oxides and new safer fuels (thoria, UC).

该提案涉及多尺度建模在核和原子水平上的应用。这项工作的独特之处在于它将核模拟与材料建模相结合。尽管要使用的技术已经很成熟，但它们从未像这里提出的那样耦合在一起。这项工作将应用最先进的、第一原理（预测）和改进的模型来研究新型材料和核材料的结构、光学、机械和热物理特性。这项研究的总体目标是对新型核材料的特性有一个基本的了解。未来三年的短期目标集中在（1）利用辐射源的组合模拟和核材料的原子分子动力学建模，以更好地、根本性地了解辐射的影响； （2）利用从头算、预测和半经验方法大规模研究辐射引起的缺陷对材料性能的影响； (3) 通过模拟确定各种核燃料的结构、机械和热物理特性； (4) 研究锕系氧化物的光学和电子性质（重点是U3O8）； (5) 为反应堆安全课程准备交互式代码。 ** 铀氧化物的半导体特性令人感兴趣，因为这些氧化物的介电常数 (e ~ 20) 远高于 SiO2 (3.5)。贫铀氧化物可以从核废料中回收，并在太阳能电池和电子产品中具有潜在的应用前景。它们也是浓缩铀生产的副产品。 U3O8是最稳定的氧化铀，但没有关于光学带隙的实验数据。我们拥有研究 U3O8 的电子结构和带隙所需的专业知识，无论是实验（在加拿大光源）还是理论上。萨斯卡通的 Cameco Inc. 可以为我们提供可以安全检查的贫化 U3O8 样品。一旦确定了带隙，光学和机械性能都将通过第一原理计算准确确定。它们将用于评估 U3O8 在太阳能电池板中的潜在应用。它将为萨斯喀彻温省当前铀矿石出口之外的铀氧化物新应用奠定基础。 U3O8 机械和结构特性的准确数据将有助于预测反应堆或废物储存室事故期间氧化铀体积增加时的应力。**我们从理论上研究了各种核燃料，特别是具有高安全性的氧化钍。导热性通过更有效的散热来防止燃料熔化。然而，燃料热导率的实验数据显示出很大的差异，并且燃耗引起的降解的影响尚不清楚。蒙特卡罗代码将用于模拟运行燃料棒中燃料中的原子位移，并评估物理燃耗。经典分子动力学代码中的参数将使用第一原理计算进行调整，并将用于评估物理燃耗引起的热导率下降。将研究铀和钍燃料行为之间的比较。**开发的纯燃料热导率相关性和包含缺陷的热导率相关性将用于新的交互式软件，用于核反应堆安全的多学科调查和事故中燃料熔化的调查与福岛类似。对于更安全的反应堆的设计来说，获得模拟铀氧化物特性的新方法和新的更安全的燃料（钍、UC）至关重要。