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On December 30, 2021, the Experimental Advanced Superconducting Tokamak team, installed at the Hefei Institute of Plasma Physics, announced that it had managed to maintain plasma for more than 17 minutes at a temperature of more than 70 million degrees. China’s fusion ambitions now seem limitless: it plans to build the world’s largest pulsed power plant. Earth could have fusion power by 2028, says the project’s lead scientist.
Nuclear fusion is considered the holy grail of energy today. Powerful, clean, safe and inexhaustible fusion energy would be a real breakthrough for humanity. However, she remains elusive. Despite the progress made by public and private entities over the past decade, no laboratory in any country has yet succeeded in building a reactor that produces more energy than is needed to start a fusion reaction. Still, researchers put the records together: recently, a Korean tokamak (KSTAR) kept plasma at 100 million degrees for 30 seconds.
Against all odds, China has just announced particularly ambitious plans: it has approved the construction of the world’s largest pulse power plant; will be located in Chengdu, Sichuan Province. Professor Peng Xianjue, a distinguished scientist from the Chinese Academy of Engineering Physics who is an expert on nuclear power, believes that his country will have fusion power within the next six years. ” Being the first in the world to achieve energy-scale release of fusion energy will mark the most important milestone on the path to fusion energy for human beings. », stated? September 9 at a meeting organized by the Beijing think tank Techxcope.
A plant that will be based on the Z machine
Producing power from fusion is a particularly complex process that requires extreme temperatures (on the order of 100 million degrees) and very sophisticated plasma containment technologies. According to Professor Xianjue, “ fusion ignition is the crown jewel of science and technology in today’s world “, he reports South China Morning Post.
In addition to the latest record for a Korean tokamak, at the end of 2021, the Joint European Torus collaboration was also distinguished, producing 59 megajoules of energy for 5 seconds – a huge step forward for this reactor, which serves as a test bed for the ITER project. These projects, like most existing experimental fusion reactors, rely on fusion by magnetic confinement. However, the future Chinese factory will be based on a completely different technology: indeed, it is planned to produce a fusion reaction by inertial confinement, carried out by axial constriction (or Z-squeezing).
This approach could prove to be more efficient and economical because Z-pinch reactors do not need complex magnetic coil arrays or expensive shielding materials. The fuel capsule (deuterium and tritium) is placed in the center of a cylindrical network composed of metal wires (tungsten or aluminum). Then a strong electrical impulse vaporizes this cylinder and turns it into plasma, while the magnetic field created by the current compresses this plasma. The sudden increase in plasma pressure generates powerful X-rays, which in turn compress the envelope containing the atoms to be fused.
Z machines can store massive amounts of electricity and release it in nanoseconds. They were originally intended for the production of nuclear weapons. This new Z-pinch machine is expected to be completed in 2025 and is expected to generate 50 million amps of electricity. That’s almost twice as much as it’s capable of producing the “Z machine” from Sandia Laboratoriesin Albuquerque, New Mexico.
Combination of fusion and fission energies to increase yield
No existing Z machine has yet succeeded in generating more energy than is necessary to create an electrical impulse. Xianjue said during his presentation that he and his team will try to start a fusion reaction with a modest amount of fuel. They intend to regulate the process to limit the pulse energy released to a few hundred million joules – roughly the same energy as a 20-kilogram bag of TNT.
But unlike most current experiments, the fusion energy produced by this Chinese device will not be directly used to power the electrical grid: the goal is to create a stream of fast particles that collide with uranium, the fuel from the “fissile” component. device. Because it is a hybrid plant based on both fusion and fission energy that Beijing wants to build.
Specifically, it will involve coating the walls of the fusion ignition chamber with uranium, which absorbs the particles produced by the fusion to produce two lighter elements – a process similar to that used in current nuclear power plants. Project scientists estimate that this combination of reactions will increase the overall thermal efficiency of the power plant by 10 to 20 times.
This, of course, could greatly accelerate the use and commercialization of fusion energy. On the other hand, this approach brings the same risks and disadvantages as current nuclear power plants – namely the risks of nuclear accidents and radioactive waste management. In addition, several issues remain to be resolved, such as the design of components capable of supporting this dual reaction.
But according to Eurasian Times, scientists claim to use different techniques than those used in the West and argue that their approaches are more effective (of course they are being developed in top secrecy). And the team’s plan is very ambitious: to produce energy from nuclear fusion by 2028 and to refine the technology for commercial use by 2035.