Isotopic, Doped Diamond Materials as a Plasma-facing Material for Fusion Power

聚变能源的开发商面临着许多挑战，其中之一是聚变反应堆的布局和建造它的结构材料。这些反应堆壁材料还执行着确保聚变等离子体被安全限制的重要工作。反应堆最内壁被称为面向等离子体的材料(PFM)，其设计必须能够承受等离子体撞击，并充当聚变过程中产生的强烈辐射的散热器。污染等因素。在选择金属烤瓷时，必须考虑耐久性、导热性和导电性。到目前为止，钨、铍和碳-石墨材料等材料一直被使用。这项研究项目与EPSRC的能源主题保持一致，旨在评估同位素纯的CVD钻石(单晶和多晶)和石墨烯作为PFM在钻石结构上的使用。现有PFM材料面临的挑战之一是它们的化学稳定性以及从反应堆壁上侵蚀出来的材料有可能对聚变反应堆的运行产生不利影响。过去曾使用碳基墙体材料，但在高能等离子体粒子轰击和吸收燃料气体的情况下，热导率的损失被证明是有问题的。对于人造钻石，这也被视为一个需要解决的问题，尽管它的使用是有利的，因为它是一种对聚变等离子体操作影响较小的轻元素。该项目将探索新的方法，以提高钻石对聚变等离子体环境的复原力，并将其作为一种金属熔体进行操作。这将包括注入高含量氢同位素的钻石以限制氚的吸收，加入高浓度的硼，以及使用石墨烯来本地化/限制氚燃料气体的保留。布里斯托尔钻石实验室将通过化学气相沉积合成高质量、导热和导电的钻石结构，并将使用布里斯托尔的材料分析设施(NanoESCA、SIMS、XRT、HSAFM)和库勒姆的材料研究设施(MRF)对其物理和电学性能进行表征。候选的钻石PFM结构将通过中子和H、D、T辐射进行实验评估，以模拟PFM操作，使用临时H3AT设施中的库勒姆设施和偏滤器科学设施。为了支持实验工作，将与英国航空航天局人员合作，使用LAMMPS和MCNP进行模型计算。预计学生每年将被借调到英国AEA至少8周，参加英国AEA赞助的实验活动和博士培训活动。

A number of challenges are faced by developers of fusion energy, one of these being the fusion reactor layout and the structural materials from which it is built. These reactor wall materials also carry out the important job of ensuring that the fusion plasma is safely confined. The inner most wall in the reactor is known as the Plasma-Facing Material (PFM) and has to be designed to withstand plasma strikes and also act as a heat sink for the intense radiation produced during fusion. Factors such as contamination. durability, thermal and electrical conductivity must be taken into consideration when selecting a PFM. Materials such as tungsten, beryllium and carbon-graphite materials have been used up until this point.This research project is aligned with the EPSRC's Energy Theme and aims to evaluate the use of isotopically pure, CVD diamond (single crystal and polycrystalline) and Graphene on diamond structures as a PFM. One of the challenges with existing PFM materials is their chemical stability and the risk of the materials eroded from the reactor wall adversely affecting the operation of the fusion reactor. Carbon-based wall materials have been used in the past but the loss of thermal conductivity under energetic plasma particle bombardment and absorption of the fuel gases has proven problematic. For synthetic diamond this has also been viewed as an issue that needs to be resolved even though its use is favourable due to it being a light element that has less influence on fusion plasma operation. This project will explore new approaches for improving the resilience of diamond to the fusion plasma environment and its operation as a PFM. This will include the infusion of diamond with high loadings of hydrogen isotopes to limit tritium absorption, incorporation of high concentrations of boron and the use of graphene to localise/limit tritium fuel gas retention. High quality, thermally and electrically conductive diamond structures will be synthesised by chemical vapour deposition in the Bristol Diamond Laboratory, and their physical and electrical properties will be characterised using material analysis facilities at Bristol(NanoESCA, SIMS,XRT,HSAFM) and the Materials Research Facility(MRF) at Culham. Candidate diamond PFM structures will be evaluated experimentally by neutron and H,D,T irradiations to simulate PFM operation using facilities at Culham in the interim H3AT facilities, and the Divertor Science Facility. To support experimental work, model calculations using LAMMPS and MCNP will be conducted in collaboration with UKAEA personnel. It is anticipated that the student will be seconded to UKAEA for at least 8 weeks each year to participate in experimental campaigns and UKAEA-sponsored PhD training activities.