Using nuclear fusion to obtain a steady supply of clean energy like the sun has been a long-standing dream of mankind. China is already at the forefront of the world in using controlled nuclear fusion to "grow the sun." In December 2020, the new generation of " artificial sun " developed by the Fusion Science Institute of the Southwest Institute of Physics of the CNNC Nuclear Industry Group - the China Circulator No. 2 M device (HL-2M) achieved its first discharge. Among the 76-person team undertaking this high-tech scientific project, 57 are young people under the age of 35. This year's May Fourth Youth Day, this team that bravely climbed to the peak of science and technology won the 26th " China Youth May Fourth Medal Collective ". A reporter from " Global Times " recently conducted an exclusive interview with China's "Sun Planting" team and listened to their story about how to realize China's "fusion energy dream" despite foreign technological blockades.
The core components of the new generation of "artificial sun" devices
are independently designed and manufactured in China
Zhong Wulu, deputy director of the Fusion Science Institute of the Southwest Institute of Physics of the China National Nuclear Corporation, said in an exclusive interview with a reporter from the Global Times, "'Artificial Sun' With its advantages of rich resources, environmental friendliness and inherent safety, it will become the ideal energy source for mankind in the future, and it is also an effective way to ultimately solve the energy and environmental problems of human society. It is of great strategic significance to my country's economic and social development and industrial construction."
However, compared with the mature application of the nuclear fission principle in nuclear power plants, humans face many difficulties and challenges if they want to "control" the thermonuclear fusion reaction.
Zhong Wulu said that the conditions for nuclear fusion to occur are very harsh. This process first needs to be carried out under extremely high temperature conditions. " The nucleus must have high enough kinetic energy, such as the temperature reaching hundreds of millions of degrees, to overcome the interference between the nuclei." Coulomb repulsion, close enough to each other to allow short-range internuclear attraction to play a major role”. In addition, it is necessary to create high-density conditions for plasma . "The density of deuterium and tritium nuclei is high enough to increase the probability of nuclear fusion reactions due to collisions between nuclei." In order to achieve controllable nuclear fusion , it is necessary to maintain a long energy confinement time. "The high-temperature and high-density nuclear reaction conditions must be maintained for a long enough time to enable the nuclear fusion reaction to continue."
According to Zhong Wulu, although the principle of nuclear fusion sounds simple, developing nuclear fusion energy is a challenge to the limits of human science and technology, because it requires the ion temperature and density of the plasma to be controlled under artificial control conditions. The "triple product" with the energy constraint time must reach a certain value. In science, this special condition that will maintain the energy balance in a nuclear fusion reactor is called the "Lawson criterion." "Only when the nuclear fusion reaction releases enough energy can the operation of the nuclear fusion reactor be maintained and considerable energy output be achieved, allowing the fusion reaction to continue."
According to China's Nuclear Energy Development "Thermal Reactor - Fast Reactor - Fusion Reactor "With the three-step strategy, China's goal is to independently develop nuclear fusion energy reactors. Among them, the new generation of "artificial sun" is an important measure for my country to develop nuclear fusion energy. It marks that my country has independently mastered the design, construction, and operation technology of large-scale advanced tokamak devices. It will provide the next step for my country to independently design and build fusion reactors. Lay a solid foundation.
Zhong Wulu said that the new generation of "artificial sun" is my country's largest and highest parameter capacity magnetic confinement nuclear fusion experimental research device. It adopts advanced structure and control methods, and its plasma volume reaches the level of existing domestic devices. More than 2 times, the plasma current capacity is increased to more than 2.5 megaamps, the plasma ion temperature can reach 150 million degrees, and high-density, high-specific pressure, and high bootstrap current operation can be achieved. The device is also the world's first advanced nuclear fusion research platform capable of realizing a variety of advanced divertor configurations under megaampere plasma current. "The core components of the device are independently designed and manufactured in China. It is an important supporting device for realizing the leap-forward development of my country's nuclear fusion energy development industry. It is also an important device for my country to absorb one of the world's largest international cooperation projects - the International Thermonuclear Experimental Reactor (ITER). ) technology is an indispensable and important platform."
Scientific and technological personnel are discussing in the vacuum chamber of the new generation of "artificial sun".
Breaking through the technical blockade and improving China's manufacturing
According to the "Global Times" reporter, the new generation of "artificial sun" consists of a vacuum chamber, coil system, generator set and support structure It is composed of other core components. Behind China’s “artificial sun”, there are a series of inspirational stories of breaking foreign technological blockades and filling domestic gaps.
Take the vacuum chamber as an example. This device provides an ultra-vacuum environment for the “artificial sun” discharge experiment, using It is used to contain high-temperature plasma of hundreds of millions of degrees, which is several orders of magnitude lower than the vacuum degree of the space environment. In the early stage of design and development, the "Sun Planting" team visited more than 10 large-scale manufacturing companies, all because of the high design accuracy of this equipment. They were told that they could not be processed due to the difficulty in manufacturing, the difficulty in controlling the welding deformation of thin-walled parts, and the lack of relevant domestic experience. The team refined the scientific design parameters into achievable engineering drawings and guided the manufacturers through joint research and development and step-by-step teaching. Processing. After 6 years of hard exploration, the team created my country's first D-shaped cross-section special material double-layer double-curvature thin-walled fully welded ring-shaped ultra-high vacuum container. The relevant process and technical indicators have reached the international leading level. The
coil system is " The discharge experiment of the "artificial sun" device provides a strong magnetic field about , 250,000 times the earth's magnetic field, to accurately and stably control high-temperature plasmas of hundreds of millions of degrees. According to the original design plan, the coil manufacturing originally adopted a "reuse and transformation" plan. With the deepening of construction and the rapid development of international nuclear fusion research, the R&D team found that if they adopt "new development", the design parameters can ensure that they reach the internationally advanced level and even achieve partial leadership. However, the development risk is extremely high and the innovation may fail. Faced with the dilemma, the team chose the more challenging "new development" based on a large number of scientific calculations and analysis. They pioneered the D-shaped bit plate detachable toroidal field coil with the largest operating current and strong magnetic field in China, a breakthrough The domestic large-section externally square and internally circular special-shaped oxygen-free copper pipes have the original production capacity limit. We have creatively mastered the domestic large-size special-shaped high-strength chromium-zirconium copper manufacturing technology, and many processes are ahead of foreign first-class devices. The
generator set is an "artificial The giant "power bank" that provides operating power from the "Sun" can release up to 1,300 megajoules of energy at a time, and its power is equivalent to the Qinshan Phase I nuclear power station. The development team has overcome the ultra-high power slip regulation and large-scale vertical six-phase pulse power generation With electromechanical braking and other technologies, we have developed China's first large-scale vertical-axis pulse generator set with completely independent intellectual property rights. Its power generation can cover the basic electricity consumption of a city with a population of one million, and some indicators also lead the international level.
Zhong Wu According to Lu, in order to ensure that the performance of the device meets the needs of physical experimental research under core-level plasma parameter conditions, the engineering and technical difficulty and process complexity of the "artificial sun" have increased significantly, constantly challenging the limits of relevant domestic engineering technologies. . "The United States once banned the sale of high-strength expansion bolts needed to build an 'artificial sun' on the grounds of core technology. Faced with this 'stuck neck' problem that must be solved, we found a breakthrough from the vast literature and went through hundreds of materials After comparison and thousands of trial productions, we finally conquered the key technology, broke the foreign blockade, and produced large-size and high-strength expansion bolts that had no domestic production precedent, reducing production costs by nearly 90% and greatly saving scientific research funds."
It is through this kind of high-intensity technical research that the "Artificial Sun" R&D team has mastered a number of core technologies. Through joint research with large state-owned enterprises, it has greatly improved the company's research and development capabilities and equipment manufacturing level of complex products, and is advancing While technological innovation also drives industrial technology upgrading.
Global Times reporters Fan Wei Cao Siqi
