Lubrication in Magnetically Confined Fusion Reactors

With the development of socially productive forces and the continuous progress of science and technology, the scope of human utilization of energy is constantly expanding, and the position of energy in life is becoming more and more important. At present, the reserves of fossil energy on the earth can only be used by mankind for another 100 to 200 years, so it is a very urgent strategic task for all mankind to explore new energy and realize energy transformation. It was not until the 1950s that nuclear reaction power plants, which provides new energy in the form of nuclear reaction, appeared on the world energy stage. After decades of development, China, as the country with the fastest growth in nuclear power generation, has put forward higher requirements for the safety technology and economic indicators of nuclear reactors. Nuclear fusion is a reliable way to sustainable energy development in the future by providing almost unlimited energy from very small amounts of fuel in a clean and safe way. Magnetic confinement nuclear fusion produces clean energy by confining high-temperature and high-density deuterium-tritium plasma discharge with a strong magnetic field. In the installation, equipment operation and maintenance are involved in the lubrication of parts. Considering the operating environment of the device, the lubricating materials used in the moving parts of the magnetic confinement fusion device not only face cyclic stress, friction, and wear but also withstand heavy load, high and low temperature alternating, high vacuum and strong and diversified radiation environment (high energy, high flux neutrons and high-density plasma, etc.) during the operation of the fusion device. Irradiation of high-energy particles causes spot defects such as vacancy and gap atoms to form inside the service lubrication materials. Under the action of the temperature field and stress field, defect clusters are aggregated to form dislocation, cavity and amorphous transformation inside the materials, leading to material embrittlement, failure and other performance degradation. These problems will affect the service safety of nuclear power reactor equipment and are the key technical problems of the system. Therefore, it is very important to understand and master the selection and service behavior of lubricating materials in the harsh nuclear environment to improve the ability of lubricating materials to resist radiation damage. For the design of nuclear energy systems, it is to ensure the safe, stable operation and later maintenance of the whole device. In this paper, the lubrication challenges and solutions of various components such as vacuum chamber, superconducting magnetic field, ion cyclotron heating system, and teleoperating system during the development of magnetic confinement fusion devices were systematically summarized, and the lubrication materials and technologies required for commercial magnetic confinement fusion reactors in the future were prospected.