At 14:02 on December 4, 2020, the nuclear fusion device known as the “artificial sun”-China Circulator No. 2 M device (HL-2M) was launched in Chengdu and realized its first discharge, which marked China’s independent control The design, construction and operation technology of large-scale advanced tokamak devices have been developed, and nuclear power research capabilities have once again made significant progress.
The HL-2M Tokamak reactor is currently China’s largest and most advanced magnetically confined nuclear fusion experimental research device. The project was approved by the National Atomic Energy Agency in 2009 and was independently designed and built by the Southwest Institute of Physics (SWIP) of China Nuclear Industry Corporation Scientists hope the device releases powerful clean energy. It uses a powerful magnetic field to confine the plasma to undergo nuclear fusion reactions. The maximum core temperature can reach 150 million degrees Celsius, which is about ten times the core temperature of the sun.
Nuclear fusion energy has many potential attractions. First of all, its fuel is relatively rich in hydrogen isotopes. One of the necessary isotope fuels: deuterium, which can be extracted from seawater. The deuterium extracted from one liter of seawater can be released in a complete fusion reaction equivalent to burning 300 liters. The energy of gasoline; and another isotope fuel: tritium, which can be generated by the reaction of neutrons with lithium. Lithium is abundant in the crust and seawater. In addition, compared with the pollutants produced by traditional nuclear reactors, nuclear waste produced by nuclear fusion has an extremely short half-life (low management costs, lower total hazards during nuclear leakage, and only need to evacuate within one kilometer at most) and higher safety ( Do not maintain the nuclear constraints will stop the reaction).
In the sun, energy is generated through nuclear fusion of atomic nuclei, which fusion of hydrogen atoms into helium atoms, which emits light and generates heat at about 620 million tons of hydrogen per second. This is also the controlled nuclear fusion device that is vividly called “man-made The reason for the sun.
The principle of nuclear fusion is not mysterious. It was proposed by scientists in 1920. In the 1940s, nuclear fusion for military purposes began to be studied, and after the 1950s, humans turned to explore the use of nuclear fusion to create energy. According to the mass-energy equation E=mc, a huge amount of energy is contained in the nucleus, and the change in the net mass of the nucleus (the difference between the mass of the reactant and the product) can cause the release of energy.
If it changes from a heavy nucleus to a light nucleus, it is called nuclear fission, such as an atomic bomb explosion; if it changes from a lighter nucleus to a heavier nucleus, it is called nuclear fusion, such as a hydrogen bomb.
The principle seems simple, but it is difficult for nuclear fusion to be precise and “controllable”, so that the energy output can be sustained and stable, because it cannot release all the energy at once like a hydrogen bomb.
Under normal conditions, the mixed state of deuterons and tritons will not produce continuous nuclear fusion. The nucleons must be brought together by external energy. Even in the center of the sun with extremely high temperature and high density, each proton has to wait billions on average. It takes only one year to participate in fusion. And because the nuclei are positively charged and will repel each other, it is difficult to make them close to each other. To overcome their repulsive force, the temperature, density and confinement time of the plasma must be properly controlled. These three conditions Indispensable.
Since the plasma will fly away soon, it must be enclosed first. The sun uses huge gravity to seal the plasma. On the earth, other methods must be adopted. Only when the plasma is heated to more than 100 million degrees can it achieve controllable nuclear fusion. On the earth, there is no material that can The high temperature plasma of 100 million degrees is wrapped, and the strong magnetic field is one of the methods invented by scientists.
When the plasma is charged, the electric charge is wound on the magnetic line of force. Therefore, as long as the magnetic field is created, the plasma can be enclosed and suspended in a vacuum. The magnetic field is used to confine the charged particles in the high-heat plasma and make them spiral. The wire moves to further heat the plasma until a nuclear fusion reaction occurs.
Currently, the world’s largest experimental tokamak reactor under construction is the International Thermonuclear Experimental Reactor (ITER) in the south of France. Construction began in 2007. The project is jointly organized by the European Union, India, Japan, China, Russia, and South Korea. It is funded and operated by seven member states including the United States. The European Union, as the sponsor of the ITER facility, contributes about 45% of the cost, and China bears nearly 10% of the procurement package for the ITER facility. The goal of the facility is to promote plasma frontier physics. Experimental research has turned the large-scale application of nuclear fusion power generation technology from expectation into reality.
According to the design of the International Thermonuclear Experimental Reactor, ITER is to produce about 500 MW of fusion power from an input power of 50 MW, with a long pulse duration of 400 to 600 seconds, and fusion of about 0.5 in its approximately 840 cubic meter reactor. g Deuterium/Tritium mixture.
Experts estimate that it will conduct the first phase of testing in December 2025. If the experiment is successful, it will assist the first batch of nuclear fusion power plants to be put into operation by 2040. ITER was initially expected to cost about 10 billion euros, but with the price of raw materials The current investment has exceeded 16 billion euros and the total cost is estimated to reach about 20 billion euros.
The peaceful use of nuclear fusion is a major strategic project for every energy-consuming country. Since the 1970s, Chinese scientists have also been researching and developing smaller versions of nuclear fusion reactors, focusing on selecting tokmak facilities as their main research direction.
Before the China Circulator No. 2 M device (HL-2M), small CT-6 (Institute of Physics, Chinese Academy of Sciences), KT-5 (University of Science and Technology of China), HT-6B (Institute of Plasma, Chinese Academy of Sciences), HL -1 (SWIP), HT-6M (Institute of Plasma, Chinese Academy of Sciences) and medium HL-1M (SWIP) and other projects.
In the next ten years, high-level experimental research will be carried out on the two main devices, EAST and HL-2M.
Among them, the advanced experimental superconducting tokamak experimental device (HT-7U) of the Institute of Plasma Physics, Chinese Academy of Sciences is also called the “Eastern Super Ring”, and the project was later renamed EAST. On September 28, 2006, the device successfully discharged for the first time, and on July 3, 2017, it realized a stable 101.2 second steady-state long pulse high-confinement plasma operation, becoming the first in the world to achieve steady-state high-confinement mode operation Tokamak nuclear fusion experimental device with a duration of hundreds of seconds.
On November 12, 2018, EAST achieved heating power exceeding 10 MW for the first time, plasma energy storage increased to 300 kJ, plasma center electron temperature reached 100 million degrees for the first time, and many experimental parameters obtained were close to the steady state of future fusion reactors The physical conditions required for the operating mode.
The completion of the HL-2M can use the unique advanced divertor position to carry out boundary plasma physics experiments under high power conditions, especially to explore future demonstration reactors under high power, high thermal load, and strong plasma-material interaction conditions , The effective removal methods and means of particles, heat flow, and helium ash complement the EAST device, which will enable my country’s core-level plasma physics research and related key technologies to reach the international advanced level, and it can also quickly absorb and digest the International Thermonuclear Fusion Experimental Reactor Brought forward technological exploration.
In science fiction movies, whether it is the planetary engine in the wandering earth, the Ark reactor in the chest of Iron Man, or the speed engine in Star Trek, people are full of imagination for powerful energy and energy, and controllable nuclear fusion Technology is the holy grail of energy in the eyes of scientists, and it is expected to be reflected in reality in the near future.