Development of Novel-Fuels with Enhanced Safety Characteristics for Use in Nuclear Power Generation

许多新兴经济体正在考虑建设数百座新的核电站，为日益电气化的经济体（包括电动汽车的电力）提供电力，并抵消导致气候变化的排放。在北美，重点是延长现有发电站的使用寿命。无论新建或翻新计划如何，核电作为基本负荷发电机继续发挥重要作用，其碳排放量低于天然气甚至太阳能发电[来源：NRCAN 2015]。自2011年3月日本福岛核电站发生事故以来，核安全和减轻严重事故的主题一直主导着核工程领域的活动。为了在核安全方面做出革命性的改变，我们必须创新我们的核电技术。虽然下一代概念，如GEN-IV反应堆的设计已经为未来的新反应堆建设带来了实质性的变化，但它们无法改变现有核电站的基本特征，这些核电站可能还有30-60年的额外发电寿命。这项研究计划的目标是开发和测试新的核燃料概念，即所谓的事故容忍燃料（ATF），从根本上提高现有运行反应堆的安全性。在核安全领域，主要使用两个指标来评估安全特性：a)堆芯损伤（CD）和b)大提前释放（LER）。假定的导致燃料熔化/错位的事件被归类为潜在的CD事件。可能向环境释放放射性物质且没有足够时间实施应急措施的极端事件称为LER。这一发现基金考察了具有以下特点的新型事故耐受燃料：a)更好的传热，从而大大增加了护套和燃料失效的边际，从而降低了cd的可能性。b)在燃料失效（在正常运行期间长期发生，特别是在核事件期间）的情况下，改善了放射性核素的保留。c)避免在CD事件中产生氢的快速氧化反应，从而防止可能导致事件发展为LER的氢爆炸。根据十多年来对纳米颗粒传热和核安全的研究结果，我认为最有潜力的ATF可能涉及纳米结构材料和核燃料的混合。在现有文献中，只发现了1篇研究加拿大CANDU设计的潜在改进的论文，该工作的重点是钚混合氧化物燃料，而不是现有的燃料供应链（天然到微浓缩铀）。这项工作将为ATF概念提供坚实的基础，并将产生具有这一新兴领域知识的HQP。

Many emerging economies are considering construction of hundreds of new nuclear plants to supply electricity for increasingly electrified economies (including power for electric vehicles) and to offset climate changing emissions. In North America the focus is on life-extensions of existing power stations. Irrespective of new build or refurbishment plans nuclear power continues to play an important role as a base-load generator with carbon emissions rated below that of natural gas or even solar power [source: NRCAN 2015]. Since the accident at the Fukushima nuclear power plant in Japan in March 2011, the topic of nuclear safety and severe accident mitigation have dominated activity within the field of nuclear engineering. In order to make transformative changes in nuclear safety we must innovate our nuclear power technologies. While next-generation concepts such as GEN-IV reactor designs have given rise to substantive changes for future new-reactor builds, they cannot change the basic features of existing plants which may have 30-60 years of additional generation life. The objective of this research program is to develop and test new nuclear fuel concepts, known as accident tolerant fuels (ATF), to radically improve safety in existing operating reactors.Within the nuclear safety field, two metrics are predominantly used to evaluate safety characteristics: a) Core Damage - CD and b) Large Early Release - LER. Postulated events that cause fuel melting/dislocation are classified as potential CD events. Extreme events that may release radioactivity to the environment and with insufficient time for implementation of emergency measures are termed LER. This Discovery Grant examines new Accident Tolerant Fuels with the following characteristics:a) Better heat transfer such that margins to sheath and fuel failures are significantly increased thereby reducing the probability of CD.b) Improved retention of radio nuclides in the event of fuel failures (those that occur both chronically during normal operation and in particular during a nuclear event), thereby reducing the amount of radiological inventory which might be released in an accident.c) Avoid the rapid-oxidization reactions which give rise to hydrogen production during CD events, thereby preventing hydrogen detonations which may cause the event to progress to a LER.Based on the results of over 10 years of research on nano-particle heat transfer and nuclear safety, I believe the best potential ATF may involve a hybrid of nano-structured materials and nuclear fuels. In the available literature only 1 paper was found examining the potential improvement to the Canadian CANDU design, and the focus of that work was Plutonium mixed-oxide fuels, and not on the existing fuel supply chain (natural to slightly enriched Uranium). This work will provide a firm basis for ATF concepts and will generate HQP with knowledge in this emerging area.