We already have a sun, why make another?

Source: Voice of China, China Central Radio and Television Station

Recently, a major breakthrough has been made in the development of nuclear fusion in my country. At 14:02 on December 4, 2020, a new generation of "artificial sun" device - China Circulator No. 2 M device (HL-2M) was completed in Chengdu and achieved its first discharge. Build a solid foundation. So, what exactly is an "artificial sun"? What technological breakthroughs and independent innovations have been achieved by China Circulator No. 2 M device? The Voice of China exclusively interviewed Zhong Wulu, deputy director of the Fusion Science Institute of the Southwest Institute of Physics of China National Nuclear Corporation.

Why do we need a second sun?

As the saying goes, everything grows on the sun, and the core temperature of the sun is about 15 million to 20 million degrees, while the metal materials on the earth will melt at about 1000 degrees. Zhong Wulu introduced that what China's "artificial sun" needs to do is to build a device on the earth that can withstand high temperatures of 100 million degrees, or even more than 200 million degrees.

Zhong Wulu: The sun is estimated to have been burning for about 5 billion years so far. Why can the sun burn forever? It is because its mass is very large, relying on this gravitational force, it can forcefully squeeze these fusion materials, that is, the hydrogen element atomic nuclei in its outer layer, to the core of the sun to achieve a very high temperature. At a very high density, nuclear fusion reactions naturally occur. "

Zhong Wulu once gave a speech "Controlled Nuclear Fusion: Lighting up Energy Dreams with an "Artificial Sun""

Director Zhong often encounters people asking him, we already have a sun, why do we need to build another sun? Director Zhong explained: "The principle of this device is similar to the principle of the sun's light and heat, which is the principle of nuclear fusion, so it is not a new sun, but a fusion device, or we say it is a fusion device. Heap, in fact, our ultimate goal is to use it to achieve nuclear fusion, and release energy to generate electricity. "

Nuclear fusion is actually the energy source of the entire universe, and the construction of the "artificial sun" is also to continuously and stably output energy through nuclear fusion reactions, and finally solve human energy problems, thereby benefiting mankind. The principles are very similar, so these devices for the purpose of exploring fusion clean energy are called "artificial suns".

How do "artificial suns" generate electricity?

Currently, the Eastern Super Ring (EAST), China Circulator-2 Both A (HL-2A) and M (HL-2M) belong to the "artificial sun" experimental device. Zhong Wulu introduced that the China Circulator No. 2 M device (HL-2M) built this time is a new generation of advanced magnetic Confinement nuclear fusion experimental research device. He said: "This device is independently designed and built by our country. It adopts advanced structure and control methods and has the advantage of advanced divertor configuration. It is currently the largest advanced tokamak device with the highest parameters in my country. Its volume is more than twice that of existing domestic devices. The current capacity of plasma can be increased to 2.5 megaamperes. The temperature of the sun can reach 150 million degrees, which means 10 times the core temperature of the sun. "

China Circulator No. 2 M device (HL-2M) was completed in Chengdu and achieved the first discharge

During the construction of the HL-2M device, the Southwest Institute of Physics of the Nuclear Industry united with many domestic research and development units in the physical and structural design of the device A number of breakthroughs have been made in the development of special materials, research and development of material connection and key components, and assembly integration. The detachable coil structure has been realized, the control and operation level has been enhanced, and the research ability of the physical experiment of the device has been improved; the high-nickel alloy hyperboloid has been overcome. Key technologies such as compression molding and welding deformation control of large vacuum containers for thin-walled parts; mastered the manufacturing process of special-shaped copper alloy thick plates with international advanced level, and realized the independent localization of high-strength expansion bolt components; successfully developed international advanced level The first large-scale vertical shaft pulse generator set in China. Driven by the construction of the HL-2M device, the key technologies such as special materials, key equipment, and extreme condition precision manufacturing mastered by the Western Institute of Physics and Technology have formed a "synchronous radiation" effect. Innovative applications in cutting-edge fields such as electronics.

China Circulator No. 2 M device (HL-2M) was built in Chengdu and achieved the first discharge

Can we control the "artificial sun"?

nuclear fusion, also known as nuclear fusion , simply put, is the process of fusion of two lighter nuclei to form a heavy nucleus, which is opposite to the principle of nuclear fission. Human beings can already achieve uncontrolled nuclear fusion, such as the explosion of a hydrogen bomb.

Zhong Wulu introduced that in order to use nuclear fusion energy , nuclear fusion must be made controllable, which means that three very stringent conditions must be met. "The first condition requires a particularly high temperature, because only when the temperature is particularly high can the nucleus have sufficient kinetic energy, that is, the nucleus will run faster. The second condition is that the density of the plasma must be sufficient High, the concept of high is that the probability of collision and polymerization reaction between atomic nuclei should be increased. The third is to control these atomic nuclei for a long time, that is, to maintain the high temperature and high density nuclear reaction conditions for a long enough time, so that Only then can nuclear fusion occur and continue.”

However, on the earth, there is no material that can directly wrap the 100 million-degree high-temperature plasma. But scientists have thought of a way - to use a strong magnetic field to confine charged particles. When Director Zhong returned to the Institute of Nuclear Science and Technology, it was just in time for the 2A team to focus on a key technology—to achieve high-constraint mode operation. After more than 10,000 experiments, the team finally realized the high-constraint model operation for the first time in China in 2009.

The "artificial sun" is not far away from us

my country's nuclear energy development implements the three-step strategy of "thermal reactor-fast reactor-fusion reactor", taking fusion energy as the final step to solve energy problems.

The expectation of human beings for clean energy is a kind of energy with no exhaust gas, no radioactive waste discharge, and abundant resources. Zhong Wulu introduced that nuclear fusion energy is precisely such an energy source. He said: "First, the nuclear fusion reaction fuel, we say that its resources are very rich, and the nuclear fusion reaction fuel deuterium can be extracted from water. The second characteristic is that the reaction of nuclear fusion is It is inherently safe, it does not have the so-called uncontrollable, and there will be no so-called explosion. Third, because of the nuclear fusion reaction, it will not emit waste gas, produce greenhouse gases, and will not produce long-lived radioactivity Therefore, it is the most ideal energy source that humans have realized so far.”

Director Zhong always likes to end with a song when he shares his research results. This is the well-known "Planting the Sun". This feeling of fusion energy is like seeing ourselves light a bonfire for the first time — glowing and hopeful. At present, judging from the general situation and status quo of international and domestic nuclear fusion research and development, the industry generally believes that the commercial application of fusion energy is expected to be realized by the middle of this century.

China Circulator No. 2 M Unit (HL-2M)

At present, the National Atomic Energy Agency is studying the layout of an integrated nuclear fusion research innovation system, creating a national-level nuclear fusion innovation research platform, an exchange platform for domestic and foreign experts and scholars, and a growth platform for young scientists , and comprehensively promote my country's nuclear fusion industry to move from a parallel to a leader.

Source: China Central Radio and Television (ID: zgzs001)