Research to enable rapid development of High Temperature Superconducting magnets for fusion energy and other applications.

托卡马克能源有限公司是一家私营公司，目标是到2030年将核聚变作为一种清洁和安全的能源。该公司的目标是通过将球形托卡马克（一种磁约束聚变装置）与高温超导（HTS）磁铁相结合来实现这一目标，高温超导（HTS）磁铁可以在紧凑型设备中提供非常强的磁场。该公司认为，高温超导球形托卡马克是快速交付商业聚变能源的关键途径。该项目旨在解决高温超导磁体技术领域的两个关键挑战，以加速用于聚变能和其他应用的高温超导磁体的发展。第一个挑战是为高温超导导体的特性和质量保证（QA）开发一种技术和战略方法，然后在几年内采购的数百公里导体上实施这一方法。这里的关键困难在于稀土钡铜氧化物（REBCO）高温超导导体的电流容量非常大，并且对温度、磁场强度、场方向和晶体的纳米结构有非常复杂的依赖关系。由于涉及高磁场和电流，在聚变磁体的最终使用条件下测量导体性能极具挑战性。因此，尽管磁体设计非常依赖于他们的知识，但完整的表征不能常规地进行。该项目将建立必要的性能指标（平衡成本、风险和信息深度），开发测量它们所需的方法，并在实际导体到达时将其实施。第二个挑战是开发用于高温超导聚变磁体的可拆卸线圈结构。高温超导磁体可以在相对较高的温度（>~ 20k）下工作，在这种温度下，冷却系统可以容纳导体之间的接头产生的大量热负荷。与传统的低温超导体（LTS）不同，高温超导导体在高温下工作非常热稳定，因此可以忍受其结构周围几度开尔文的温度变化。这使得可以考虑可拆卸的线圈结构，其中磁铁的匝数可以在组装和拆卸期间相互连接和断开。对于托卡马克磁体来说，这是一个非常有吸引力的设计选择，对于一些线圈（例如极向场线圈（pf））来说，将螺纹插入其他线圈组（例如环向场线圈（tf））是有利的。如果线圈是可拆卸的，例如真空室和中子屏蔽的组装，那么托卡马克更广泛的组装过程也会大大简化。可拆卸线圈的开发是一个多方面的问题，包括开发新的低电阻连接方法，在托卡马克装配大厅环境中的实际实施方法，以及设计更宽的磁铁系统以容纳接头（包括绝缘方法和磁铁工作原理）。

Tokamak Energy Ltd is a private company targeting the delivery of fusion as a clean and safe energy source by 2030. The company aims to do this by combining spherical tokamaks, which are a type of magnetic confinement fusion device, with high temperature superconducting (HTS) magnets, which can deliver very strong magnetic fields in compact devices. The company believes that HTS spherical tokamaks are the key route to delivering commercial fusion energy on a rapid timescale. This project aims to address two key challenges in the field of HTS magnet technology, in order to accelerate the development of HTS magnets for fusion energy and other applications. The first challenge is to develop a technical and strategic approach towards the characterisation and quality assurance (QA) of HTS conductors, then implement this on several hundred kilometres of conductor procured over a period of several years. The key difficulty here is that the current capacity of rare-earth barium copper oxide (REBCO) HTS conductors is extremely large and has a very complex dependence on temperature, magnetic field strength, field direction and the crystal's nanostructure. Measurement of conductor performance under the end-use conditions in fusion magnets is extremely challenging due to the high magnetic fields and currents involved. Therefore, complete characterisation cannot be carried out routinely despite magnet designs relying crucially on their knowledge. This project will establish the necessary performance indicators (balancing cost, risk and depth of information), develop the methods required to measure them, and implement this on the real conductor as it arrives. The second challenge is the development of dismantlable coil structures for HTS fusion magnets. HTS magnets can be operated at relatively high temperatures (>~20 K) at which substantial heat loads from joints between conductors can be accommodated by cooling systems. Unlike conventional low temperature superconductors (LTS), HTS conductors operated at high temperatures are extremely thermally stable and can therefore tolerate substantial temperature variations of several degrees Kelvin around their structures. This enables dismantlable coil structures to be considered, in which the turns of the magnet can be connected and disconnected from one another during assembly and disassembly. This is an extremely attractive design option for tokamak magnets, where it is advantageous for some coils (e.g. poloidal field coils (PFs) ) to be threaded inside other coil sets (e.g. the toroidal field coils (TFs)). The wider assembly process for tokamaks is also greatly simplified if the coils are dismantlable, for example the assembly of vacuum chambers and neutron shields. Development of dismantlable coils is a multifaceted problem involving development of novel low resistance jointing methods, practical implementation methods in a tokamak assembly hall environment, and design of the wider magnet system to accommodate the joints (including insulation methods and magnet operating principles).