Schematic diagram of Max Planck Lab's core stellarator?

Everyone present, including the old man at the head, was hooked to be interested.

"Previously, Academician Wang said that the Max Planck laboratory has made a major breakthrough in the first inner wall material of the stellarator, and this conclusion can be said to be or not."

Lu Yi took the laptop from Zhang Qing's hand, connected it to the projector and projected the screen.

Seeing the schematic diagram on the projection light screen, the experts in the field of nuclear fusion were stunned, what is this gap that directly reaches the orbit of the plasma?

After waiting for a while, someone seemed to understand, and a trace of shock flashed in his eyes, and then Lu Yi continued: "The first time I knew about this construction scheme was when Max Planck Labs announced the start of the construction of the demonstration reactor.

At that time, two engineers from Max Planck Labs told us that Max Planck Labs had always had this option, and then I asked Tomorrow Group to use the capital relations in Western Europe, and after this period of hard work, I finally obtained this specific information.

Of course, the fact that such a highly confidential information can be obtained so easily may also have something to do with the fact that they don't take this information too seriously.

Because even if this design structure is made public, there are only a few countries in the world that can realize it, and for the time being, only Max Planck Labs and Germany where they are located have the conditions to realize it and have in-depth research on the stellarator. ”

"The approximate structure of the stellarator must be well understood, and the orbit running from the plasma is divided into the first inner wall, the lithium breeding cladding, the cooling layer, the shielding layer, the vacuum chamber, and the outermost outer magnetic field coil, in which the deflector also works on the first inner wall.

In the past, the biggest problem with stellarators was that plasma turbulence was unpredictable, resulting in the shape of the confined magnetic field not being perfectly matched by the plasma.

As a result, in the edge area of the magnetic field, a large number of plasma with a temperature of more than 100 million degrees Celsius will penetrate the magnetic field, forming a terrifying plasma irradiation on the first inner wall, causing the temperature of the first inner wall to rise rapidly.

The subsequent plasma turbulence model has been broken through, and the optimized control scheme has made the confinement magnetic field and the plasma fit more perfectly, which reduces the plasma irradiation by more than 99%.

Of course, it is not perfect, and it cannot be perfect, after all, even if the sun cannot perfectly bind all plasma.

However, plasma irradiation has dropped by more than 99 percent, which also means that this problem has been solved and there are commercial standards, so the remaining problems of the stellarator are several major problems such as neutron irradiation, tritium retention, tritium proliferation and recycling.

Now controlled nuclear fusion uses deuterium-tritium fusion, which can be extracted from seawater, and the earth content is very large.

Because the half-life of tritium is only 12 years, it is almost non-existent in nature and can only be obtained through the reaction of neutrons and lithium, which makes tritium extremely rare and valuable.

In order for controlled nuclear fusion to be commercialized, the first problem is to meet the repeated recycling of tritium, which is recycled through the reaction of neutrons and lithium produced by tritium-deuterium fusion.

If the lithium neutron recovery system does not meet the application standards, there will be less and less tritium in the reactor, and the fusion reaction will eventually be stopped. ”

"In that case, Professor Lu, do you have any ideas for solving these problems?"

The big man of the Energy Bureau, who was sitting at the bottom of the old man, asked a little curiously.

"There are ideas, but the material properties are not up to them."

Lu Yi shook his head, and continued: "Deuterium-tritium fusion, a tritium nucleus and a deuterium nucleus fusion produce a helium nucleus plus a high-energy neutron containing 14 MeV energy, and release 17.6 MeV of energy.

The neutron energy released by deuterium-tritium fusion is too high, and strong neutron irradiation will cause the inner wall material to fall off or even crumble, and be involved in the plasma and cause major safety accidents.

In addition to the denaturation and brittleness of the material, high-energy neutrons will also blow up cavitations in the material like blowing up balloons, which will form an accumulation and retention problem for tritium produced by the reaction between neutrons and lithium, affecting the recycling of tritium.

In order to solve these problems, the material of the first inner wall must make a breakthrough, improve the resistance of the material to neutron irradiation, reduce the generation of cavitation, and the transmutation products should also be non-radioactive products.

In addition, because the inner wall material is directly facing the high-temperature plasma, this has high requirements for the heat resistance, thermal stress, and heat dissipation performance of the inner wall material.

If the heat resistance is not good, the inner wall material will not be able to withstand the high temperature caused by discrete plasma irradiation in the first place, and if the thermal stress is not good, the material will be denatured as soon as the temperature rises.

If the heat cannot be dissipated in time to stabilize the temperature, the energy accumulation will cause the denaturation of the material, and the boiling point temperature of the lithium cladding is only 1340 degrees Celsius, and the high temperature will directly cause the vaporization of lithium metal.

These demanding material performance requirements are the current problems of stellarators, and there is no material in the world that can meet these performance indicators. ”

Lu Yi explained very carefully, and the sentences were smooth and clear about the current problems encountered by the stellarator, and the people present listened very carefully.

Originally, the big man of the Energy Bureau and the old man, who didn't know much about these technical details, also had a relatively clear idea of the current problems of the stellar mimic in their hearts.

"The material problem of the first inner wall bothered us, and of course it bothered Max Planck Labs."

Lu Yi enlarged the schematic diagram on the screen and said: "They solved this problem by using a tricky method, processing the ceramic material into a movable chain network structure, and then opening an opening on the stellar simulator to stick into it."

It is like a piece of weaving, spiraling around the outer diameter of the plasma's orbit, and subjecting the plasma radiation energy to circle and then come out.

Originally, in the Spiral Stone 7-X stellarator, they used a 2 mm ceramic interlayer.

But this time, everything in the demonstration reactor was redesigned and manufactured, so more space could be reserved in advance, so they used two layers of 2mm ceramic interlayer this time.

Inorganic non-metallic ceramic materials have good neutron penetration, which makes them not block neutrons, thus affecting the recycling of tritium.

In addition, the poor thermal conductivity of ceramic materials, which was originally eliminated as the first inner wall material, has now become its advantage, which can absorb and withstand more heat gathered inside it and transport more heat out of the outside.

Based on the design data of this schematic diagram, we have roughly calculated that the working temperature of the first inner wall can be reduced to between 500 and 600 degrees Celsius after the blocking and heat removal of the first two layers of ceramic movable interlayers. ”

"500 to 600 degrees Celsius?"

Several nuclear fusion experts, including Academician Wang and Professor Zhang, who were present, couldn't help but exclaim, and they understood what this temperature meant.