Follow the light day by day
Approaching China's new generation of "artificial sun" HL-2M
Planetary engines, intelligent quantum computers, space elevators... For a period of time, the "hard-core technology" elements in the movie "The Wandering Earth 2" have attracted widespread attention.
do you know?
Many of the equipment in the movie have prototypes in reality.
"You can imagine, we are responsible for realizing it." Recently, on social media, a poster of China National Nuclear Corporation detonated the Internet, showing the planetary engine in the movie and China's new generation of "artificial sun" device (HL-2M ), China Circulator No. 2 A device (HL-2A).
Netizens couldn't help feeling excited, and sighed, "It turns out that behind Chinese science fiction is made in China."
Science fiction into reality.
In the movie, the planetary engine pushes the earth to use the energy released by nuclear fusion, and HL-2M and HL-2A are important devices for my country to explore controlled nuclear fusion, and are called "artificial suns".
Among them, the HL-2M device is currently the largest and highest-parameter magnetic confinement fusion experimental research device in my country.
Not long ago, it was selected as one of the "Top Ten State-owned Enterprises of 2022".
Why are these devices called "artificial suns"?
Why do we have to create a "sun"?
What technological breakthroughs and independent innovations have been achieved in the new generation of "artificial sun"?
The reporter recently interviewed relevant comrades in charge of the Southwest Institute of Physics of the China National Nuclear Corporation. Let us follow the "sun builders" and explore the mysteries of the new generation of "artificial suns".
Inexhaustible raw materials, low fuel consumption, high energy, clean and friendly products
Controlled nuclear fusion, the ideal "ultimate energy source"
The Southwest Airport in Shuangliu, Chengdu, Sichuan Province, is located in the Southwest Institute of Physics of the Nuclear Industry.
This is the earliest professional research institute engaged in the development of nuclear fusion energy in my country.
The 22-year-old building of the Fusion Science Institute of the Research Institute is the "home" of the new generation of "artificial sun".
Can humans really create the sun?
Facing the reporter's question, Zhong Wulu, director of the Institute of Fusion Science of the Southwest Institute of Physics of the Nuclear Industry, gave the answer: "Artificial sun" does not really build a sun, but a device that uses the principle of the sun to emit light and generate heat. Continuous and controllable output of energy.
"Why can the sun continue to shine and heat? It is because it is undergoing nuclear fusion reactions all the time." Zhong Wulu told reporters that the ultimate goal of our "building the sun" is to generate electricity through nuclear fusion.
As we all know, the energy crisis is considered to be the biggest problem facing the development of human society.
Scientists turn their attention to nuclear energy, and nuclear energy mainly has two forms: nuclear fission and nuclear fusion.
At present, the world's commercial nuclear power plants use nuclear fission energy, that is, a heavier atomic nucleus (such as uranium) is split into two or more lighter atomic nuclei through a nuclear reaction process, and energy is released from them.
However, uranium reserves are limited, and it is still difficult to meet human needs in the long run.
The process of nuclear fusion is just the opposite. It refers to the fusion of lighter atomic nuclei into heavier atomic nuclei under ultra-high temperature conditions, and releases huge energy, and the energy released per unit mass is much higher than that of fission.
The sun's light and heat come from the energy released by nuclear fusion reactions.
"The advantages of nuclear fusion energy are very obvious. First, the reserves of fuel on the earth are extremely rich; second, it does not produce high-level radioactive nuclear waste and is environmentally friendly; third, it has inherent safety and other advantages." Zhong Wulu further explained.
The reporter learned that the main raw material supporting the nuclear fusion reaction can be extracted from seawater.
According to calculations, the deuterium extracted from one liter of seawater can release energy after a complete fusion reaction, enough to drive a car from Beijing to Hainan.
According to the calculation of seawater resources on the earth, theoretically, the energy released by fusion reaction is enough for human beings to use for tens of billions of years, which is almost endless.
Data is the most convincing.
According to Zheng Xue, a senior engineer born in the 1990s and a gold medal member of the Science Popularization Team of the Southwest Institute of Physics of the Nuclear Industry, a 1 million-kilowatt thermal power station consumes about 2.1 million tons of coal every year; a nuclear power station of the same level consumes about 30 tons of enriched uranium every year .
And if a nuclear fusion power plant of 1 million kilowatts is built, it only needs to consume about 0.12 tons of fuel per year.
Because of this, nuclear fusion energy is considered an ideal "ultimate energy source". Once successfully applied, it will fundamentally solve the problem of human energy demand.
However, in order to utilize nuclear fusion energy, nuclear fusion must also be made controllable.
"In the 1950s, the successful detonation of the first hydrogen bomb meant that it became a reality for humans to create nuclear fusion reactions, but it was uncontrollable and instantaneous. We 'created the sun' through a special way. Make the nuclear fusion reaction process controllable, and let it continuously output fusion energy for our use." Zhong Wulu said.
It is a world-class problem to make nuclear fusion controllable, and three very harsh conditions must be met at the same time, which is the so-called "fusion triple product".
"The first one is that it needs a high temperature of hundreds of millions of degrees Celsius, because only when the temperature is extremely high, the atomic nuclei will 'run' faster. The second is that the density of the plasma must be high enough so that the collisions between the atomic nuclei and the polymerization reaction will occur. The probability will increase. The third is to control these nuclei for a long time, that is to say, to maintain the high-temperature and high-density nuclear reaction conditions for a long enough time. Only in this way can nuclear fusion occur and continue.” Zhong Wulu said.
What is the concept of a high temperature of hundreds of millions of degrees?
You know, the core temperature of the sun is only 15 million to 20 million degrees.
Metal materials on the earth will melt at about 1000 degrees.
Clever scientists use strong magnetic fields to suspend high-temperature plasma to achieve isolation from materials.
That is to say, let the high-temperature plasma carry out the fusion reaction under the confinement of the magnetic field.
Up to 2.5 trillion amperes of current, 150 million degrees of high temperature independent innovation to create a new generation of "artificial sun"
Wang Jin, a senior technician at the Southwest Institute of Physics of the Nuclear Industry.
Comparing and analyzing the experimental data, checking and repairing the vacuum chamber of the main engine...Recently, he and his colleagues have carried out a new upgrade on the HL-2M device to prepare for the upcoming next round of discharge experiments.
In the host computer room of the new generation of "artificial sun", various pipelines and cabinets surround a giant "tire" machine, which is dazzling.
However, Wang Jin knows every part here like the back of his hand.
"The tens of thousands of parts on it were installed and debugged by myself and my colleagues." Wang Jin said proudly.
The reporter learned that the HL-2M device is currently the largest and highest-parameter magnetic confinement fusion experimental research device in my country. It adopts advanced structure and control methods. The plasma volume is more than twice that of existing domestic devices, and the plasma current capacity is improved. The temperature of plasma ions can reach 150 million degrees Celsius when it exceeds 2.5 megaamperes, and can achieve high density, high specific pressure, and high bootstrap current operation.
At the same time, it is also the first nuclear fusion advanced research platform in the world that has the ability to realize various advanced divertor configurations under megaampere plasma current.
"More importantly, the core components of the device are all designed and built independently by our country." Zhong Wulu said.
According to reports, the new generation of "artificial sun" is composed of core components such as vacuum chambers, coil systems, generator sets and supporting structures.
Behind its design and construction, there are too many stories of breaking foreign technology blockades and filling domestic gaps. From core components such as vacuum chambers to special expansion bolts, they are constantly challenging the limits of domestic related engineering technology.
"The 'tire'-shaped device in the middle with a diameter of about 5 meters and a height of about 3 meters is a vacuum chamber." Wang Jin told reporters that only the design and manufacture of the container has gone through 6 years of difficult exploration.
According to reports, the HL-2M device mainly relies on strong magnetic fields to confine high-temperature ions in a vacuum environment without contact with any materials.
And this ultra-vacuum environment is several orders of magnitude higher than the requirements of the space environment.
In the initial stage of design and development, the scientific research team did a lot of research and visited more than 10 large-scale manufacturing companies, but was told that it could not be processed due to reasons such as high design precision, difficult manufacturing, difficult control of welding deformation of thin-walled parts, and no relevant domestic experience.
The team quickly adjusted scientific thinking to engineering thinking, refined scientific design parameters into achievable engineering drawings, and guided manufacturers to process through joint research and development and hands-on teaching.
This is a huge pressure on the team that has been engaged in basic scientific research for a long time and lacks engineering experience.
However, in the end, my country's first D-shaped cross-section special material double-layer double-curvature thin-walled fully welded annular ultra-high vacuum container was developed and manufactured, and the relevant process and technical indicators have reached the international leading level.
The coil system is also very important. It provides a strong magnetic field about 50,000 times that of the earth's magnetic field for the discharge experiment of the HL-2M device, so as to accurately and stably control the high-temperature plasma of hundreds of millions of degrees.
According to the original design, the coil manufacturing "renovation" was the most reliable and efficient solution at that time.
However, the scientific research team chose to re-develop.
In the end, it created the largest domestic operating current strong magnetic field D-shaped bit plate type detachable toroidal field coil, breaking through the original production capacity limit of the domestic large-section outer square inner circle special-shaped oxygen-free copper tube, and uniquely mastered the domestic large-size special-shaped high-strength Chromium-zirconium copper material manufacturing technology, many processes are ahead of foreign first-class equipment.
Not only that, the installation accuracy and cleanliness of the relevant parts of the device are also extremely demanding.
"There are more than 40,000 parts installed in our vacuum chamber, all of which are installed manually. If any part is not installed firmly, or is not in the designated position, the team experiment of hundreds of people cannot be carried out. At the same time, due to space constraints All components are compact and need to be installed layer by layer, which is difficult to install.” Wang Jin introduced that the first “line of defense” outside the vacuum environment——the installation of the “first wall” is what he faces. biggest challenge.
In order to protect the various measurement devices behind, the "first wall" is densely distributed in the entire vacuum chamber, including multiple layers of functional and structural materials, the large ones are the size of playing cards, and the small ones are only the size of fingers.
"It sounds as simple as 'tiling tiles', but the requirements for clearance and flatness are extremely high. The height difference between two adjacent pieces of material cannot exceed 1mm, and the gap cannot exceed 2mm, and the working space is very limited. According to his recollection, it took more than half a year to install the entire "first wall". Only the eyes are left exposed.
Constantly making new breakthroughs and creating new records Nuclear fusion ignition is gradually approaching reality
The host of the HL-2M device is separated by a wall, which is the central control room of the device.
On February 9, Li Bo, a young post-90s director of the Control and Information Research Office of the Institute of Fusion Sciences, coordinated the relevant systems in the control room and conducted a test experiment on the peripheral auxiliary heating system.
He also has a title - "the driver of the 'artificial sun'".
"It is mainly responsible for the design, construction and operation of the 'central nerve' of the control device, and finally realizes the control of the plasma." Li Bo explained.
When the reporter mentioned the new record created by the HL-2M device in October 2022-the plasma current exceeded 1 million amperes (1 megaamperes) for the first time, Li Bo was quite excited.
According to him, in order to realize nuclear fusion power generation, fusion ignition must first be realized, which is a prerequisite.
"It's like drilling wood to make fire, first achieve fusion ignition, and then only need to continue to add 'firewood' to continue to output energy externally."
However, it is easy to light a firewood, but it is difficult to ignite a fire with nuclear fusion.
As mentioned above, the product of the three variable parameters of plasma temperature, density, and energy confinement time must exceed a specific value.
The plasma current breakthrough of 1 million amperes means that key parameters such as plasma density limit and energy confinement time have been significantly improved.
"This also means that we have taken another important step towards fusion ignition, which is of great significance to my country's deep participation in the world's largest 'artificial sun' - the ITER experiment of the International Thermonuclear Experimental Reactor and the independent design and operation of fusion reactors." Li said. Bo said.
However, with each experiment, each round of discharge, there will be new problems waiting to be solved.
"Just like the older generation who 'made the sun', we have to conquer one mountain after another." Li Bo told reporters that the institute is gathering elite soldiers from all walks of life to integrate multiple superior resources, and the two-level discipline inspection committee of the institute is strengthening Supervision linkage, fully guarantee the basic scientific research, and accelerate the solution to the bottleneck problem of the key core technology of the "artificial sun".
According to reports, my country's experimental research on controllable nuclear fusion began in the 1950s, almost in sync with the world.
After more than half a century of development, various types of magnetic confinement fusion research devices have been developed, such as pulsed magnetic mirrors, angular pinch devices, stellarators, superconducting magnetic mirrors, and tokamaks.
The current mainstream "artificial sun" device is a tokamak, and the HL-2M device is a tokamak device.
"In fact, it is to fill a large ring-shaped vacuum container with gas, then ionize the gas into plasma, and then use a strong magnetic field to control the charged particles and make them suspend in the vacuum container." Zhong Wulu said.
Prior to this, the Southwest Institute of Physics of the Nuclear Industry has successively developed HL-1, HL-1M, and HL-2A series devices, among which HL-1 is my country's first medium-sized tokamak experimental device, known as my country's first " "Artificial Sun" experimental setup.
In 2006, China, the European Union, the United States, Russia, Japan, South Korea and India jointly signed the ITER project initiation agreement. This project is currently one of the largest and most far-reaching international scientific projects in the world. The largest international scientific and technological cooperation project, and has continuously made new breakthroughs.
Today, some technologies in China's magnetic confinement nuclear fusion research have reached the international leading level.
"The realization of nuclear fusion ignition is gradually becoming a reality." For HL-2M, the only technology platform in my country that has the ability to carry out core-level plasma physics experiments, this group of "builders of the sun" is full of confidence, "In the future, HL-2M will Continue to carry out follow-up experiments in an orderly manner, impact higher parameters such as plasma current and ion temperature, comprehensively improve the three parameters of nuclear fusion, and realize a new leap in my country's "artificial sun" research."
"Every time I see the dazzling light of the plasma through the big screen in the central control hall, I think it is very beautiful, just like the first time a human being sees himself lighting a bonfire—glowing brightly and full of hope." Li Bo said with emotion I hope that the lights of our country will be lit by nuclear fusion energy as soon as possible.
(Reporter Wang Zhen from China Discipline Inspection and Supervision News)