The construction of the BEST host for China's nuclear fusion device has begun comprehensively
On October 1st, a key breakthrough was made in the construction of China's nuclear fusion device BEST.
The base weighing over 400 tons was successfully installed and will be used to carry the BEST host with a total weight of about 6700 tons, marking the comprehensive start of construction for this major country's heavy machinery host.
In the future, this device will be the first internationally validated demonstration of nuclear fusion power generation, and is expected to light up the first light through nuclear fusion by 2030.
Nuclear Fusion: The Ultimate Password for Exploring Cosmic Energy
From the mystery of the continuous burning of the sun for 4.6 billion years to humanity's ultimate pursuit of "inexhaustible" clean energy, nuclear fusion has always been one of the most dazzling research directions in the field of science. It is not only the core driving force for stars to emit light and heat in the universe, but also a cutting-edge technology that has the potential to completely change the human energy landscape.
Simply put, nuclear fusion refers to the process of lighter atomic nuclei (such as hydrogen isotopes deuterium and tritium) overcoming electrostatic repulsion (Coulomb repulsion) between nuclei at extremely high temperatures and pressures, colliding and fusing into heavier atomic nuclei (such as helium), while releasing enormous amounts of energy. This process follows Einstein's mass energy equation "E=mc ²" - the total mass of the fused new nucleus is slightly less than the sum of the masses of the two nuclei before fusion, and the reduced mass (mass loss) will be released in the form of energy, with an energy density far exceeding any energy currently used by humans.
To understand the energy intensity of nuclear fusion, only one set of data comparison is needed: the energy released by a fusion reaction of 1 kilogram of deuterium tritium mixture is equivalent to the heat generated by the combustion of 27000 tons of standard coal or the energy generated by the complete combustion of 120 tons of gasoline; However, the energy released by nuclear fission fuel of the same quality (such as uranium-235) is only about 1/4 of that released by nuclear fusion. More importantly, the fuel sources for nuclear fusion are almost infinite - deuterium is widely present in the seawater on Earth, and each liter of seawater contains deuterium that can release energy equivalent to 300 liters of gasoline through fusion. The deuterium contained in seawater worldwide can meet the energy needs of humanity for over a million years; Although tritium is extremely rare in nature, it can be artificially prepared by reacting lithium (an element abundant in the Earth's crust) with neutrons, and there is no "fuel shortage" problem.
However, achieving controllable nuclear fusion is not an easy task, and its core challenge lies in "how to create and maintain extreme conditions for nuclear fusion". Inside the Sun, gravitational collapse creates a high temperature of 15 million degrees Celsius and a high pressure of 250 billion atmospheres, naturally meeting the "ignition conditions" for nuclear fusion; But on Earth, humans cannot replicate such strong gravity and can only simulate extreme environments through technological means. Currently, there are two mainstream research directions:
One type is magnetic confinement fusion, represented by the International Thermonuclear Experimental Reactor (ITER), commonly known as the "artificial sun". It uses a super strong magnetic field (about 100000 times stronger than the Earth's magnetic field) to confine plasma (the fourth state of matter where atomic nuclei and electrons are separated) with a temperature of up to 150 million degrees Celsius in a circular vacuum chamber (tokamak device), avoiding high-temperature plasma from contacting the device wall and causing cooling, while continuously heating the plasma to meet the conditions required for fusion reactions. In 2023, China's "Artificial Sun" device (EAST) achieved a continuous operation of plasma at 120 million degrees Celsius for 403 seconds, setting a world record and laying the foundation for subsequent experiments of ITER.
Another type is Inertial confinement fusion, represented by the National Ignition Facility (NIF) of the United States. It focuses 192 high-energy lasers on a deuterium tritium target with a diameter of only a few millimeters, heats the target to 30 million degrees Celsius and compresses it to 100 times the density of the Earth's core in a very short period of time (about 10 trillionths of a second), utilizing the inertia of the plasma to complete the fusion reaction in an instant when diffusion is not possible. In December 2022, NIF achieved "net energy gain" for the first time - the energy released by fusion reactions exceeded the energy of the input laser, marking a major breakthrough in the inertial confinement route.
In addition to high energy density and abundant fuel, nuclear fusion also has ultimate safety and environmental friendliness. Unlike nuclear fission, nuclear fusion reactions will immediately terminate once extreme conditions are lost (such as magnetic field interruption or laser stop), and there is no risk of "core meltdown"; The main reaction product is helium (a non-toxic and harmless inert gas), which does not produce long-term radioactive waste like nuclear fission and has almost no pollution to the environment.
Although human beings have not yet achieved commercial nuclear fusion power generation (expected to require 30-50 years of technological breakthroughs), every step of progress in nuclear fusion, from natural fusion of the sun to gradual breakthroughs in the laboratory, is pushing humanity closer to the goal of "energy freedom". In the future, when nuclear fusion power plants are spread all over the world, humanity will completely break free from dependence on fossil fuels, solve global problems such as climate change and energy shortages, and usher in a new era based on clean and unlimited energy.
