After years of research, China's scientific research team has successfully overcome a large number of international common problems, and for the first time in the world, it has realized the high constraint operation of continuous discharge of 50 million degree plasma for 101.2 seconds. This breakthrough has laid an important technical foundation for the development and utilization of nuclear fusion clean energy.
After a major breakthrough at the end of 2016, China has made another milestone breakthrough every six months, achieving a leap from 60 seconds to 100 seconds, which shows that the development speed of fusion research in China is far ahead of other countries. Its importance is that the high constraint model is considered by physicists as the best working state of future nuclear fusion power plants. This breakthrough has qualitative significance for the subsequent research of nuclear fusion power plants.
There is no doubt that this breakthrough will lay a solid foundation for the construction of China's next-generation nuclear fusion device, the world's first nuclear fusion power plant, the proposed China Fusion Engineering Test Reactor (cfetr), and the development and utilization of clean energy for international nuclear fusion.
China's new generation 'artificial sun' experimental device has made a major breakthrough
What is' artificial sun '
In the current era of human being, energy applications are ubiquitous, but so far, the use of all kinds of energy is more or less limited by the total amount, time or region, and the development of fusion energy will help mankind to completely solve the energy needs.
Scientific experiments tell us that when the atoms with smaller mass merge into the atoms with larger mass, mass reduction and energy release will occur, that is, nuclear fusion reaction. Unlike nuclear fission, in which atoms merge with each other for fusion, their nuclei must be brought close to the flying meter level. To reach this distance, the nucleus needs to be heated to tens of millions of degrees Celsius, so that it has a great kinetic energy to overcome the great repulsion between charges. Therefore, nuclear fusion reaction is also called thermonuclear reaction.
Compared with other kinds of energy, the fuel supply of nuclear fusion is abundant. Deuterium, the main fuel of nuclear fusion energy, is abundant in seawater. The total amount of deuterium in seawater is about 45 trillion tons. According to the energy consumed in the world, the fusion energy of deuterium in seawater can be used for tens of billions of years. Tritium, another main fuel for nuclear fusion, can be made of lithium. Although the reserves of lithium on earth are less than that of deuterium, from the known reserves of more than 200 billion tons, human beings have enough to use it for deuterium tritium reaction.
Known as a large-scale nuclear fusion reactor, the sun is generating huge energy every day, with a central temperature of 15 million degrees Celsius. Although nuclear fusion energy is inexhaustible, how to use fusion energy safely and controllably is a problem that human beings have been trying to solve.
In order to solve the problem of fusion control, many fusion experimental devices have been set up around the world. In the mid-1980s, the United States, France and other countries launched a multi billion euro International Thermonuclear Experimental Reactor (ITER) program, aiming to build the world's first controlled thermonuclear fusion experimental reactor, and to deliver huge clean energy for human beings. This process is similar to the solar energy generation process, so the controlled thermonuclear fusion experimental device is also known as "artificial sun".
Steady state high constraint operation mode is the basic operation mode of ITER plan, and also the key scientific problem to be solved in the future. ITER is expected to ignite in 2025, producing the first plasma. China joined the program in 2003 and takes on 10% of the work in the project.
Chinese and western angle 'artificial sun'
Although China initially took on a small amount of work in ITER plan, its role in the plan became more and more important over time. In 2016, the core components of the thermonuclear fusion reactor developed by China took the lead in international certification. In the international competition, Chinese researchers took the lead in exploring and selling the innovative process of three materials closely combined, and withstood the test of extreme high temperature environment 20% higher than the design standard in the experiment conducted by the authority. The industry believes that this is China's significant contribution to the international thermonuclear fusion experimental reactor project.
In addition to participating in ITER project, China is also developing its own fusion experimental device, which is named East. East is the world's first all superconducting nuclear fusion experimental device independently designed and built by Chinese scientists in 8 years. It passed the national acceptance in 2007. Its scale is smaller than ITER, but both of them are all superconducting non-circular cross-section tokamaks, i.e. their plasma configuration and main engineering technology foundation are similar, and East is at least 10 to 15 years earlier than ITER.
East, an experimental facility for all superconducting tokamak fusion in China
In recent years, East has achieved a series of international leading experimental results. The fourth generation of China's nuclear fusion experimental device, Dongfang super ring, is 11 meters high, 8 meters in diameter and 400 tons in weight. In November 2016, East became the world's first tokamak fusion experimental device to achieve steady-state high constraint mode operation duration of minutes. This time, East achieved a breakthrough in the order of hundreds of seconds, which is the longest world record for plasma controlled in high confinement mode.
It is understood that ITER will adopt RF dominated low momentum injection operation mode and active water-cooled tungsten diverter structure. East is the only superconducting tokamak in the world with these two characteristics and long pulse operation capability. Its steady-state operation mode will provide important reference for ITER and future nuclear fusion reactors.
As an important international long pulse fusion experimental platform, in recent years, East has successively completed the upgrading and transformation of auxiliary heating, tungsten divertor, plasma physical diagnosis and other systems, overcome the key technical problems such as heating and current drive, measurement of distribution parameters, in-depth research and basic solution of RF wave coupling, high constraint plasma stability control, plasma and wall phase Interaction physics, heating and current driven transport under low momentum, impurity transport and control are a series of physical problems closely related to steady-state operation.
China and the West are obviously at a disadvantage in their struggle against the artificial sun.
Western worries
On April 25, 2016, the first set of ion cyclotron antenna built by the Institute of plasma physics of the Chinese Academy of Sciences for West, a French fusion experimental device, was completed and delivered to France. This is the first time for China to export nuclear fusion engineering technology to France, and it is also the first time for China to export the industry's highest standard nuclear fusion key components to the world.
Obviously, China's rapid development has caused other countries' concerns. The proposed cfetr will be put into operation in 2030 with an initial capacity of 200 megawatts, which will be increased to gigawatts in the next 10 years, exceeding the capacity of all commercial fission reactors in Daya Bay. If China becomes the first country to commercialize fusion technology, its economic and geopolitical advantages will be more obvious.
In recent years, China's influence in ITER project has increased significantly. It is rumoured that China will use the knowledge obtained from ITER to speed up the construction of cfetr. The other six participants in ITER project, Japan, South Korea, Russia, the United States, India and the European Union, even discuss to kick china out of the international project team. But the reality is that ITER, which has been plagued by years of delays and huge overspending, may not continue if China no longer participates.
Among the seven participants, ITER has the lowest number of Chinese employees at the beginning, and now it is second only to the EU. "For other countries, the best choice is to accept or even support China's leading fusion research," said Steven Cowley, Dean of the Christchurch college at Oxford University and former director of the British fusion center in kalem.