China Press the "Acceleration Key" for Humanity to Realize the Dream of Unlimited Clean Energy Nuclear Fusion | China | China Net

China Net commentator Leshui

Recently, there have been frequent reports of successful research on controllable nuclear fusion in China. On August 25th, for the first time, the new generation artificial sun "China Circulation 3" achieved high constraint mode operation under a plasma current of 1 million amperes, following the 403 second steady-state high constraint mode plasma operation of China's fully superconducting tokamak on April 12th. The breakthrough of key technological challenges such as high constraint mode, 403 seconds, and 1 million amperes marks another important step towards "fusion ignition" in China's nuclear fusion research, and also means that humanity's dream of obtaining unlimited clean energy is coming true.

The energy issue has always been one of the main bottlenecks that constrain the development of human society. Today, 82% of global energy consumption comes from fossil fuels, and the resulting greenhouse gas emissions have also laid the foundation for global climate change. On the other hand, although existing nuclear power plants do not produce greenhouse gases, nuclear fission reactions may bring serious nuclear pollution. In 1986, the Chernobyl nuclear power plant accident contaminated over 4000 square kilometers of land, and more than 4000 people died from cancer and other diseases caused by nuclear radiation. Currently, the nuclear contaminated water being discharged by Japan is expected to cover the entire North Pacific in 1200 days. The great harm of nuclear pollution is alarming, therefore, the call to abolish nuclear power is constantly heard around the world.

The energy issue is a tight curse worn on human heads, and the search for clean and abundant energy has become a goal pursued by various countries. Controllable nuclear fusion is hailed as the "holy grail" in the field of clean energy, and is therefore highly anticipated. Unlike nuclear fission reactions, nuclear fusion reactions have no radioactivity and naturally do not produce nuclear contamination. Moreover, one of the raw materials for nuclear fusion, deuterium, has extremely abundant reserves in the ocean -0.03 grams of deuterium per liter of seawater, which can generate energy equivalent to burning 300 liters of gasoline in nuclear fusion reactions. It is said that once controllable nuclear fusion technology is breakthrough, deuterium in the Earth's oceans can be used by humans for 10 billion years. At that time, humanity will solve the energy problem once and for all.

Dreams are grand, but the road is winding. The implementation conditions of controllable nuclear fusion are extremely demanding: firstly, it is necessary to create a high-temperature environment above 100 million ℃ to overcome the repulsive force between atomic nuclei; Secondly, it is necessary to maintain a sufficiently high density so that sufficient collisions can occur between atomic nuclei; Finally, it is necessary to ensure a sufficiently long energy confinement time to avoid rapid energy loss of high-temperature plasma. In the 1950s, these three conditions were summarized by British physicist Lawson as the famous "Lawson criterion". According to Lawson's criterion, only when the product of temperature, density, and constraint time is greater than a certain value, can the energy output of nuclear fusion exceed the energy loss, and the nuclear fusion reaction can be sustained and stable, that is, successfully achieving fusion ignition.

Nowadays, China's controllable nuclear fusion device can operate at 150 million ℃, so meeting the first condition is not a problem. For the latter two conditions, scientists found that the density and energy confinement time of the plasma are directly proportional to the current of the plasma. That is to say, the higher the current of the plasma, the higher the product of the last two parameters. According to calculations, 1 million amperes is a necessary condition for achieving fusion ignition. Therefore, it is not an exaggeration to say that China's breakthrough in this key technological field is an important milestone in the development process of controllable nuclear fusion for humanity.

But we should also see that the road ahead is still long. The ultimate realization of fusion ignition requires the collective wisdom and efforts of all humanity. In 2006, China joined the International Thermonuclear Fusion Experimental Reactor Program and became one of the seven members of the board of directors. ITER aims to build reactor level nuclear fusion devices to verify the technological feasibility of peaceful use of fusion energy. It is reported that the under construction ITER thermonuclear fusion experimental reactor is currently the largest and most complex magnetic confinement fusion device in the world. The device was installed in 2020 and is scheduled to be ignited for the first time in 2025, with nuclear fusion experiments starting in 2035. China has undertaken approximately 9% of the tasks in the construction of ITER and has successfully completed the first piece manufacturing of its core component, the first wall for enhancing heat load, contributing "Chinese wisdom" to the smooth implementation of ITER. It is worth mentioning that while achieving technological breakthroughs, the "China Circulation 3" has also verified the feasibility of high constraint operation mode for ITER.

There used to be a "50 year curse" in the nuclear fusion industry, which means that humans will always be "50 years away" from using nuclear fusion energy. But now, as human understanding of nuclear fusion technology becomes more comprehensive, one technological challenge after another is being overcome. Especially with the orderly promotion of ITER construction, the commercial application schedule of controllable nuclear fusion has gradually become clear. Duan Xuru, the chief expert in the field of nuclear fusion reactor technology at China National Nuclear Corporation, once predicted to the outside world that by around 2050, humans may truly use nuclear fusion energy. From this perspective, humanity is emerging from the "50 year curse" and the dream of unlimited clean energy is expected to become a reality in the foreseeable future. And China is pressing the "accelerator button" to achieve this great dream.

Editor and Reviewer: Tang Hua, Zhang Yanling, Cai Xiaojuan