Safer fuel and cladding for future nuclear reactor

最近发生在福岛的悲惨事故清楚地表明，迫切需要设计更安全的核燃料。如果燃料的导热性增加，铀基反应堆的安全性可以得到改善;这将降低燃料温度，防止反应堆堆芯熔化和燃料包壳失效。更高的导热率还将降低热应力，防止燃料裂化并延长其寿命。第四代反应堆，如超临界水冷（SWC）坎杜反应堆，将具有更高的热效率，并将在更高的温度和压力下运行，因此开发用于燃料包壳的新材料至关重要。我们的工作将集中在用放电等离子烧结制造新型高导热复合燃料，并测试可在高温下工作的包层材料。结合实验研究和预测模拟将使我们能够为SWR核反应堆的安全运行提出核材料建议。建造钍反应堆可以显著提高能源生产的安全性。然而，有几个重要的与材料有关的问题必须解决。Candu Energy Inc.，作为钍基坎杜反应堆的设计者，他为我们指出了钍燃料在高温下的哪些物理和机械特性还不为人所知，而这些特性是设计所必需的。我们计划应用最先进的第一原理（预测）建模来获得必要的数据。新的实验技术将首次用于分析结构和测量高达2800°C的大范围温度下的热特性。将详细研究热性能和选定的力学性能对微观结构的依赖性。我们的综合方法，从头算模拟与创新的实验相结合，将有助于事故容忍燃料和更安全的燃料包壳系统的未来坎杜反应堆的发展。

Recent tragic accident in Fukushima clearly demonstrates urgency of the design of safer nuclear fuel. The safety of uranium based reactors can be improved if thermal conductivity of the fuel is increased; this would lower the fuel temperature, prevent melting of the reactor core and the failure of fuel cladding. Higher thermal conductivity would also lower thermal stresses, prevent fuel cracking and increase its longevity. Generation IV reactors like Supercritical Water Cooled (SWC) Candu reactor, will have higher thermal efficiency and will be operating at higher temperatures and pressures and therefore development of novel materials for fuel cladding is critical. Our work will be focused on manufacturing novel high thermal conductivity composite fuel with spark plasma sintering, and testing materials for cladding that can operate at high temperatures. Combined experimental investigations and predictive simulations would allow us to make recommendations for nuclear materials for safer operation of SWR nuclear reactors. Safety of energy production can be significantly improved when thorium reactors are build. There are however several important material-related problems that have to be solved. Candu Energy Inc., designer of thorium based Candu reactor, identified for us what physical and mechanical properties of thorium fuel at high temperature are not well known, and these properties are required for their design. We plan applying state of the art, first principle (predictive) modelling to obtain necessary data. New experimental techniques will be used, for the first time, to analyse structure and measure thermal characteristics at large range of temperatures, up to 2800°C. The dependence of thermal, and selected mechanical properties on microstructure will be studied in details. Our comprehensive approach, combining ab-initio simulation with innovative experiments, will contribute to development of accident tolerant fuel and safer fuel cladding systems of future Candu reactors.