The world's largest "artificial sun": Can only China complete the final crucial step?
Chinese construction teams have long been well - known around the world, but the task they're about to undertake this time is a bit different.
At the end of February 2024, the ITER project, the world's largest "artificial sun," signed a contract for the assembly of vacuum chamber modules with a Sino - French consortium led by China Nuclear Engineering Corporation under the China National Nuclear Corporation.
After successfully installing the "heart" equipment of ITER, China National Nuclear Corporation has become the sole contractor for the installation of the ITER main unit.
Why is a Chinese enterprise responsible for installing the world's largest "artificial sun"?
Artificial Sun
Nuclear reaction is the most efficient energy production method known to humanity, with two types: nuclear fission and nuclear fusion. The corresponding weapons are atomic bombs and hydrogen bombs respectively.
Zhengjieju has previously introduced nuclear - powered container ships. The fourth - generation molten salt reactor they use represents the current pinnacle of nuclear fission technology.
Compared with nuclear fission, what we most commonly encounter is actually nuclear fusion. Just look up during the day, and you can see it - the sun is constantly undergoing nuclear fusion reactions, emitting light and heat.
The principle of nuclear fusion is simpler than that of nuclear fission. Lighter atomic nuclei, such as deuterium (D) and tritium (T), combine to form heavier atomic nuclei, such as helium, while releasing a huge amount of energy.
Schematic diagram of the nuclear fusion reaction
The principle is simple, but it's difficult to achieve.
Since nuclear fusion requires extremely high temperatures, the nuclear fusion technology currently mastered by humans is all thermonuclear fusion technology. From the R & D route, atomic bombs are developed first, followed by hydrogen bombs. Because to detonate a hydrogen bomb, an atomic bomb must be detonated first.
This is true for military applications, and the same goes for civilian ones.
Generating electricity using nuclear fission is no longer something new.
However, humans have not yet succeeded in generating electricity through nuclear fusion.
The nuclear fusion in hydrogen bombs releases too much energy instantaneously to be used for power generation. What humans need is controllable thermonuclear fusion.
How to create an "artificial sun" has become the goal that scientists from various countries have been tirelessly pursuing.
In the 1950s, Soviet scientists proposed a concept of using superconductors to generate an extremely strong magnetic field to confine energy. Its core component is called a tokamak, which is used to achieve thermonuclear fusion.
The upgraded Russian tokamak T - 15MD in 2021
In 1985, at the Geneva Summit, the United States, the Soviet Union, Europe, and Japan jointly launched the International Thermonuclear Experimental Reactor project, namely the ITER project, as one of the landmark actions to end the Cold War.
In 1988, the research and design work of the ITER project began.
After integrating global fusion research results, spending 13 years and $1.5 billion, the research and design was finally completed in 2001.
In 2007, construction of this world's largest "artificial sun" officially started.
The ITER project initially had only four members: the United States, the Soviet Union, Europe, and Japan. Later, it expanded to seven members: the United States, Russia, Europe, Japan, China, South Korea, and India, and the number of collaborating countries has also increased to 35.
With a long time span and high project difficulty, the ITER project is considered the largest global collaborative project by all of humanity after the space station.
According to the plan, if everything goes smoothly, all construction work will be completed in 2025.
By 2050, the ITER project will achieve continuous and safe energy output on a commercial scale.
Like many international collaborations, there is also political gaming behind the ITER project.
The ITER project is so important that everyone wants to gain the leading role.
Among them, the competition between France and Japan is the most intense.
France has rich experience in nuclear power and is willing to invest. Coupled with the fact that the European Union contributes the most funds to the entire project, it finally won the majority of votes.
Japan has always been at the global leading level in thermonuclear fusion research and is also generous in its investment. However, it has a major drawback: it is located in an earthquake - prone zone.
Aerial view of the ITER project. The tallest black building is its tokamak part
Finally, the ITER project was located in the small town of Saint - Paul - le - Durance, about 80 kilometers north of the southern French port city of Marseille.
Facing Numerous Difficulties
It seems that the longer the delay in the deadline, the more it becomes the fate of large - scale projects.
The ITER project has mainly encountered two technical problems.
First, in the installed 19×11 - meter (62×36 - foot) gas chamber, dimensional errors were found in the block joints that need to be welded together.
In the design concept, fusion requires compressing the nuclei of light atomic elements in super - hot plasma together. Therefore, the plasma needs to be held in a tokamak, that is, a closed toroidal chamber, by a strong magnetic force.
If the dimensions of the block joints are incorrect, the tokamak won't just leak a little gas. It is very likely to explode directly.
Second, in the selection of heat - insulation boards designed to protect the outside world from the huge heat generated by nuclear fusion, data simulation has revealed significant problems with the existing materials.
The metal of the cooling pipes densely distributed on the heat - insulation boards is prone to aging in drastic temperature changes, producing cracks that penetrate the entire pipe, posing a great safety hazard.
Cracks were found in the pipes during the inspection of ITER
Pietro Barabaschi, the then - director - general of the project, once used the words "This will be a problem for months or even years" to express the severity of the situation.
According to his estimate, due to these two problems, it is impossible to complete the project in 2025, but it still seems possible to complete the entire plan by 2035.
Compared with the delays caused by technical problems, the lack of funds is even more frustrating.
When the project was launched in 2006, the participating countries jointly raised 5 billion euros for a ten - year period. Unexpectedly, this amount of money was quickly exhausted.
At the beginning of 2023, the ITER official statistics showed that according to the current project progress and expenditure, the estimated total cost would exceed 20 billion euros.
The latest documents indicate that even this amount is no longer valid, and the real situation is definitely worse.
Construction components borne by each country in the ITER project
Without money, the project can only be postponed.
Internal staff are very pessimistic, believing that the remaining technical challenges will cause the budget to increase geometrically.
The construction of the ITER project is at risk of getting out of control.
China Enters the Scene
For a long time in the past, China was excluded from the ITER project.
The apparent reason was that China's level of fusion research was insufficient.
Of course, this reason doesn't hold water.
In fact, as early as 1994, China's first circular - cross - section fully superconducting tokamak fusion experimental device, EAST "Hefei Super - ring" (HT - 7), was successfully developed.
This made China the fourth country after Russia, France, and Japan to possess a superconducting tokamak device.
The world's first fully superconducting tokamak main unit built by China
Even so, when most of the seven member countries didn't have their own superconducting tokamak devices, ITER still refused to admit China.
In 2003, a turning point emerged.
After Canada failed in the competition for the project location, it angrily announced its withdrawal.
There was suddenly a funding gap of 1 billion euros in the ITER project. Considering China's financial strength, ITER finally agreed to China's participation.
China's participation also had a spill - over effect.
The United States had withdrawn from the ITER project in 1998 under the pretext of strengthening basic research.
After China expressed its willingness to participate in consultations at the beginning of January 2003, the United States announced its re - participation in the ITER project at the end of January.
The United States' return clearly shows that it saw the hope of the project's success due to China's participation.
China's performance has indeed lived up to expectations.
Although China joined the project the latest, it has become the biggest guarantee for the ITER project to progress to the present.
To date, the four most important installation milestones of ITER have all been completed by the Chinese.
In May 2020, the successful hoisting of the Divertor Water Cooled Structure (DWS) base was the first step.
The DWS base is the most important core equipment in the ITER tokamak device. It is not only the first large - scale component to be installed but also the foundation for all important equipment, serving as a safety barrier.
The DWS base after hoisting, with an aesthetically pleasing industrial design
The DWS base weighs 1,250 tons, and the installation accuracy must be controlled within 2 millimeters.
For such an extremely difficult task, a team of only 48 people from China National Nuclear Corporation successfully completed it and also broke the installation accuracy record for large - scale equipment hoisting in China's nuclear energy industry.
After the base was installed, four months later, the hoisting of the lower cylinder of the DWS began.
Although this "little guy" only weighs 400 tons compared to the previous one, it is still equivalent to the weight of two Boeing 747 airplanes, and its size accounts for one - third of the ITER tokamak device. The technical difficulty of the hoisting operation is not small.
In January 2021, the successful hoisting of the DWS cold shield (LCTS) completed the installation of the third major component of the tokamak device.
In April 2021, the successful installation of the poloidal field superconducting coil PF6 marked the successful completion of the quadruple hoisting of the ITER core equipment by China and also marked the full - scale start of the installation work of the magnetic system of the International Thermonuclear Experimental Reactor.
The PF6 coil is one of the lowest - lying, heaviest, and most difficult - to - manufacture superconducting magnets among all ITER superconducting magnets. It is also one of the most important coils determining the success or failure of the ITER device's operation. It took more than seven years to manufacture and was completed by the Institute of Plasma Physics of the Chinese Academy of Sciences.
Five months later, the last lower main magnet PF5 of the tokamak was also successfully installed.
It should be noted that this was during the pandemic, and China didn't delay the work at all, demonstrating the true demeanor of a responsible major country.
Here, we must mention again the news at the beginning of the article.
Photo of the signing ceremony
According to the original plan, the ITER vacuum chamber modules to be hoisted by the Chinese team were supposed to be assembled by Japan.
For this purpose, Japan jointly developed the JT - 60SA with the European Union as a pilot project.
It was installed in 2020, debugged for three years, and put into operation in December last year.
Japan's tokamak JT - 60SA
The project was on the verge of starting, so why did ITER suddenly