Energy and the Physical Sciences:Beta-enhanced thermionic energy converters and nuclear batteries employing nanostructured diamond electrodes

对退役的Magnox和AGR反应堆的辐照石墨的废物管理和处置是英国核工业面临的主要挑战。据估计，来自英国退役反应堆的辐照石墨(约90,000吨)约占目前中级废物(ILW)库存的三分之一，这是一项重大的财务负担。这一分类是根据辐照石墨的碳14浓度预测得出的，这相当于国家碳14库存的大约40%。英国核工业并不是唯一面临这一辐照石墨废物管理挑战的国家。目前估计，全球库存约为250,000吨；法国、俄罗斯、美国有大量库存，日本、意大利、德国和西班牙数量较少。这项建议旨在解决这一废物问题，并为其处理提供具有成本效益的解决方案；回收材料作为一种新型热离子能量转换器的原料，称为贝塔增强型热离子钻石转换器(BTDC)。该建议将研究如何利用贝塔辐射来改善钻石电极材料的运行性能，并试图展示一种以更低的单位成本和更高的效率生产可再生能源的颠覆性技术。集中热能可以从许多来源获得，包括太阳能、地热和核能。这种能量可以通过一种叫做热离子能量转换器的装置转换成电能。这种装置在20世纪50年代和60年代正在密集开发，作为为航天器提供动力和从核反应堆中获取电力的手段。这些器件的性能主要受到缺乏能够表现出低于1 eV的稳定低功函数的材料电极表面的限制。这限制了该技术的应用范围，仅限于那些可以在1200摄氏度以上提供热量的设备。锂化纳米钻石是这一技术障碍潜在解决方案的关键部分。由于钻石表面的独特功能化，它具有非常大的负电子亲和力。这种表面具有许多有益的性质，包括化学稳定性、温度稳定性、高光电产额和低功函数。这种锂化金刚石表面的新颖性质也使其在辐射探测器、高亮度电子源、电流放大器和离子源中的应用具有吸引力。这项提议寻求在热离子转换器中最大限度地发挥这种钻石材料的好处：将其与等离子体纳米结构结合以吸收热能，并结合贝塔辐射源以增强热能到热离子的转换。

The waste management and disposal of irradiated graphite from decommissioned Magnox and AGR reactors is a major challenge for the UK nuclear industry. It is estimated that irradiated graphite (~90,000 tonnes) from the UK's decommissioned reactors represents about one third of the current Intermediate Level Waste (ILW) inventory, a significant financial liability. This classification arises from the predicted carbon 14 concentration of irradiated graphite which equates to approximately 40% of the national carbon 14 inventory. The UK nuclear industry is not alone with this irradiated graphite waste management challenge5. It is currently estimated that the global inventory is of the order 250,000 tonnes; with significant quantities in France, Russia, USA and smaller amounts in Japan, Italy, Germany and Spain. This proposal seeks to address this waste problem and provide a cost effective solution for its disposal; re-cycling the material as a feedstock for a novel type of thermionic energy converter, termed a Beta-enhanced Thermionic Diamond Converter (BTDC).This proposal will investigate how beta radiation can be used to improve the operating performance of diamond electrode materials and seek to demonstrate a disruptive technology for producing renewable energy at a lower unit cost and with improved efficiency. Concentrated thermal energy can be harvested from numerous sources including Solar, Geothermal and Nuclear. This energy may be converted into electricity by a device called a thermionic energy converter. Such devices were under intensive development in the 1950s and 1960s as a means to power space craft and extract power from nuclear reactors. The performance of these devices was primarily constrained by the lack of a material electrode surface that could exhibit a stable low work function of less than 1 eV. This limited applications of the technology to those that could supply heat at temperatures exceeding 1200 centigrade. Lithiated nanodiamond offers a key part of a potential solution to this technological barrier. It possesses a very large negative electron affinity due to a unique functionalisation of the diamond surface. This surface has a number of beneficial properties including, chemical, temperature stability, high photoelectric yield and low work function. The novel properties of this lithiated diamond surface also make it attractive for applications in radiation detectors, high brightness electron sources, current amplifiers and ion sources. This proposal seeks to maximise the benefits of this diamond material in a thermionic converter: combining it with plasmonic nanostructures to absorb thermal energy, incorporating a beta radiation source to enhance the conversion of heat to thermionic energy.