Thermal transport properties of complex salts systems in solid and liquid states for new energy sources applications

拟议的研究计划的目的是开发一个强大的和系统的方法来预测复杂的熔融和固体盐多组分系统的热传输性能。目标有两个：第一，缓解实验数据的严重缺乏，以协助太阳能和核工业设计最佳材料;第二，从微观角度了解液态和固态复盐内的热传递机制，特别是涉及溶液中的合金效应。如今，材料科学在很大程度上依赖于模型和数值模拟来预测材料的行为，例如，优化工业过程和设计新材料。当人们想要预测复杂材料的热物理，结构和热性质作为组成，温度和约束的函数时，已经表明密度泛函理论（DFT）和平衡分子动力学（EMD）是具有最佳预测能力的原子尺度模拟的类别。虽然原子尺度模拟可以预测材料在某些特定温度、组成和约束条件下的性质，但它们不能正式表示在广泛的组成和温度范围内的这些性质。为了实现这一点，必须理解所研究的性质背后的物理学，并且必须将性质制定为控制性质随温度、组成和约束的演化的物理参数的函数。熔盐的导热率和热扩散率是设计用于聚光太阳能发电（CSP）或核熔融板条反应堆（NMSR）材料的相变材料（PCM）时要考虑的关键特性，这些材料今天被认为是有前途的能源，以减少我们对化石燃料能源的依赖，因此有助于减少温室气体排放。由于其高存储容量、低成本和良好的热性能，LiCl-NaCl-KCl-MgCl 2（低LiCl）被认为是用于CSP应用的下一代PCM的良好候选者。然而，通过添加诸如CaCl 2、SrCl 2和ZnCl 2的添加剂，可以在保持低熔化温度的同时提高储热能力和耐腐蚀性。 同样地，LiF-NaF-BeF 2-UF 4-ThF 4-PuF 3的热输运的理解和分析公式是下一代NMSR的燃料设计中的重要挑战。为了实现这一点，有必要了解热传输和局部结构之间的关系。 对于第一次，拟议的研究允许准确地预测复杂材料的热导率和扩散率的CSP和NMRS材料从原子尺度模拟和理论建模。加拿大的利益将是重要的研究可持续的替代能源的化石燃料。

The objective of the proposed research program is to develop a robust and systematic approach to predict the thermal transport properties of complex molten and solid salts multicomponent systems. The objective is two-fold: first, alleviate the severe lack of experimental data in order to assist the solar and nuclear industry to design optimal materials and, secondly, understand, from a microscopic point of view, the thermal transport mechanisms within complex salts in both liquid and solid states, especially involving alloying effects in solutions. Nowadays, materials science is strongly dependent on models and numerical simulations to predict the behaviour of materials in order, for instance, to optimize industrial processes and to design new materials. When one wants to predict the thermophysical, structural and thermal properties of complex materials as a function of composition, temperature and constraints, it has been shown that Density Functional Theory (DFT) and Equilibrium Molecular Dynamics (EMD) are the classes of atomistic scale simulations with the best predictive capability. If atomistic scale simulations could predict materials properties at some specific temperature and compositions and  constraints, they can not formally represent these properties in a wide range of compositions and temperatures. In order to achieve this, the physics behind the studied properties must be understood and the properties must be formulated as a function the physical parameters governing the property evolution with temperature, composition and constraints. The thermal conductivity and thermal diffusivity of molten salts are key properties to consider in the design of Phase Change Materials (PCMs) for Concentrate Solar Power (CSP) or Nuclear Molten Slats Reactor (NMSR) materials which, today, are considered as promising sources of energy to reduce our world dependence on fossil fuels energy, therefore contributing to the reduction of greenhouse gas emissions. Due to its high storage capacity, low cost and good thermal properties, LiCl-NaCl-KCl-MgCl2 (low in LiCl) is considered as a good candidate for next generations of PCM for CSP applications. However, by adding additives such as CaCl2, SrCl2 and ZnCl2 the heat storage capacity and corrosion resistance can be improved while keeping a low melting temperature.  Likewise, the understanding and the analytical formulation of the thermal transport of LiF-NaF-BeF2-UF4-ThF4-PuF3 is an important challenge in the fuel design for the next generations of NMSR. To achieve this, it is necessary to understand the relationship between the thermal transport and the local structure.  For the first time, the proposed research permits to predict accurately the thermal conductivity and diffusivity of complex materials for CSP and NMRS materials from atomistic scale simulations and theoretical modelling. Benefits to Canada will be important for research of a sustainable alternative energy sources to fossil fuels.