After receiving the data from Zhao Guanggui, Xu Chuan read through it carefully.
The problem of irradiation of high-energy neutron beams has been a century-long problem that is being studied all over the world.
The most troublesome thing about high-energy neutrons is not the radiation they carry, but that they can collide with the nuclei of different elements.
When neutrons collide with various atomic nuclei, the phenomenon of "neutron excitation" will occur, producing unstable isotopes, making materials radioactive and damaging the structure of materials.
To put it simply, it looks like the original material is a family of four, two neutrons and two protons forming a loving family.
Then foreign high-energy neutrons hit the nucleus and were forcibly inserted into it like a mistress. Then, the family was broken and imperfect.
At present, the scientific community generally uses neutron moderating materials and slow neutron absorbing materials to intercept neutron irradiation when dealing with the problem of neutron irradiation.
Among them, neutron moderating materials are divided into two types: heavy and light elements. Heavy elements are mainly common metal materials such as lead, tungsten, and barium.
They can block fast neutrons and reduce the energy of the neutron beam, turning it into slow neutrons.
Neutrons that have been slowed down by heavy elements need to be further slowed down by light elements before they can be absorbed by slow neutron absorbing substances.
This step mainly uses water, paraffin, polyethylene and other high polyhydrogen materials for processing.
Only slow neutrons that have been treated with light elements can be completely absorbed and destroyed by materials containing lithium or boron, such as lithium fluoride, lithium ozone, boron oxide and other materials.
Otherwise, even the slowest neutrons can be destructive to materials or human organisms.
Just dealing with neutrons is so troublesome, and the first wall material of controllable nuclear fusion also has to withstand various problems such as high temperature, high-energy deuterium and tritium particles, gamma rays, and ion pollution.
Even if materials constructed through atomic recycling technology and radiation gaps have the ability to absorb radiation and rays, it is quite difficult to find a material that can allow neutrons to pass through and maintain self-healing in the face of high temperatures.
Especially after excluding metal materials as an option, it becomes even more difficult.
After all, there are not many non-metallic materials that can withstand temperatures of thousands of degrees.
Ceramic materials count as one, carbon materials count as graphite, and diamonds are also carbon materials, and composite materials also count, but there are many types, and only some of them are available.
At present, these are the non-metallic materials that can withstand temperatures above 3,000 degrees Celsius.
As first wall materials, these materials basically have their own shortcomings.
So Xu Chuan was quite surprised when he heard Professor Zhao say that the new material they developed might have the potential to be used in first wall materials.
After all, it has only been two or three months since he officially issued the order to study the first wall material.
Even if he pointed out the direction and related methods from the beginning, with the assistance of the materials calculation mathematical model from the Sichuan and Hai Institute of Materials Research, the speed was still a bit too fast.
It took Xu Chuan ten minutes to carefully read through the data in his hand.
Judging from the information at hand, Zhao Guanggui and the others developed a carbon nanotube, carbon fiber reinforced silicon carbide, and hafnium oxide-based composite material.
In terms of properties, it is similar to high-temperature-resistant composite ceramic materials and has most of the properties of high-temperature-resistant and high-temperature ceramic materials.
The difference is that because the main structure is made of carbon nanotube and carbon fiber reinforced silicon carbide materials, the thermal conductivity has been greatly improved compared to ceramic materials.
The thermal conductivity of ordinary ceramic materials is between 01/·, while the thermal conductivity of this composite material is 211/·, which exceeds the 40/· of graphite.
Of course, the thermal conductivity of 0/· is nothing in some special ceramics.
For example, the thermal conductivity of silicon carbide c ceramic substrate can reach /·, and the thermal conductivity of aluminum nitride aln ceramic substrate can reach /.
These two ceramic substrates have the best thermal conductivity among ceramic substrates, but their high temperature resistance is not enough.
Most silicon carbide will melt when it exceeds 1600 degrees, while aluminum nitride can be stable up to 2200 degrees, but still does not meet the requirement of 3000 degrees.
Of course, if the temperature is just not up to standard, the temperature can still be maintained through water-cooling equipment. The key point is the destruction of metal bonds by neutron irradiation.
Although alumina is a ceramic material, the aluminum-metal bond is the core supporting bond, and neutron irradiation is particularly damaging to the metal bond.
As for carbon nanotube materials and carbon fiber materials, although they can withstand temperatures exceeding 3,000 degrees in an oxygen-free environment, the absorption of deuterium and tritium raw materials by simple carbon materials is too serious.
As a result, pure carbon materials, such as graphene and carbon nanotubes, are difficult to apply to the first wall.
As for the reinforced composite material developed by Zhao Guanggui and others, it can withstand ultra-high temperatures exceeding 3,400 degrees Celsius in an oxygen-free environment.
This value, if compared among pure metals, would be comparable to that of tungsten.
If it is an alloy, it is still some distance away from the melting point of tantalum hafnium pentacarbide ta4c421 degrees Celsius.
However, it is enough to be used on the first wall of a controllable nuclear fusion reactor.
The most critical thing is the absorption of deuterium and tritium raw materials. This can be seen from the test results. This composite material will not combine with the material itself unless the high-energy deuterium and tritium ions hit the surface of the material out of control.
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Putting the document in his hand on the table, Xu Chuan looked up at Zhao Guanggui and asked with interest:
"It's a bit interesting. Judging from the cross-section electron microscopy of the material, it seems that the atomic recycling technology and radiation gap structure caused the carbon nanotubes to combine with the hafnium oxide substrate. The chemical bonds of the carbon nanotubes replaced the oxygen of the hafnium oxide substrate.
Chemical bonds form a uniquely ordered carbon nanotube-hafnium crystal structure."
"This unique arrangement of carbon nanotubes and hafnium crystal structure should be the key point for this composite material to withstand high temperatures and no longer absorb deuterium and tritium ions."
"Is there a specific inspection on this process?"
For him, all the detailed data of a material are displayed in front of him, and it is not difficult to judge the core key points of this material.
The current composite material is a special carbon nanotube hafnium crystal structure, which he has never seen before.
Zhao Guanggui nodded and said: "We did an examination, but the results were not ideal. We cannot separate the crystal structure you mentioned, and we cannot reproduce this unique crystal structure using carbon nanotubes and hafnium oxide alone."
"So currently, we can only obtain the detection data of this material, and the core crystal structure data cannot be obtained."
After the test data of this material came out, someone in the research team came up with the same idea as Xu Chuan, speculating that this unique crystal structure was at work.
However, there is no way to isolate this special structure in the future, and there is no way to confirm whether it is playing a core enhancement role.
Hearing this, Xu Chuan touched his chin and started thinking.
If it cannot be separated, it is indeed impossible to judge, but this does not have a big impact, as long as the materials can be used.
Judging from the testing data, both thermal conductivity, high temperature resistance, and general physical properties of strength meet the needs of the first wall material.
Of course, the more critical point is not these ordinary performances, but the resistance to high-energy fields such as deuterium and tritium high-energy particle impact, gamma rays, ion pollution, and the most critical resistance to neutron irradiation.
The former is not a big problem, as the atomic circulation technology and radiation gap structure have been verified.
There are also test results in the data. Although it is not complete yet, it can be seen, and it is quite excellent.
As for the latter, the latter has not yet been tested.
Neutron irradiation experiments are not that easy to do.
Interested, he asked: "How did you come up with this material?"
He saw traces of the two material construction technologies of 'atomic circulation' and 'radiation gap' from the information in his hand.
The most obvious one is the special crystal structure gap shown in the cross-sectional structure diagram, which is the crystal structure used to absorb beta radiation.
Hearing this question, Zhao Guanggui smiled sheepishly and said: "Strictly speaking, the idea of this material was not thought of by me alone."
"After you arranged for me to study carbon materials last time, I went to Professor Han Jin and Academician Peng to learn about the two technologies you developed, the atomic circulation technology and the radiation gap."
"During the discussion, Professor Han Jin mentioned the radiation electric energy semiconductor conversion material you developed when studying nuclear waste. Considering that the first wall will also face strong radiation problems, I think some carbonization can be doped into the carbon nanomaterials.
Silicon material is used as an impurity to manufacture semiconductors and is used to derive electrical energy converted from radiant heat energy, thus maintaining the stability coefficient of the material itself to a certain extent."
"We conducted research along this route, and then gradually added additional hafnium oxide materials as reinforcing agents with the help of the material model from the Chuanhai Materials Research Institute."
"Unexpectedly, hafnium oxide and carbon nanotubes as reinforcing agents have undergone unexpected changes. The two formed a special crystal structure, which not only reduced the thermal conductivity of carbon materials, but also brought new changes.
The shortcomings of carbon materials absorbing deuterium and tritium raw materials are optimized.”
Hearing this, Xu Chuan was a little surprised and asked: "So it's just luck?"
After a pause, he continued with a smile: "Of course, in materials science, luck is also a part of strength."
Zhao Guanggui scratched his head in embarrassment.
Indeed, apart from some empirical processes, this material research and development can be said to be completely unexpected.
No one expected that after hafnium oxide is added as an additive to carbon materials, with the assistance of atomic recycling technology, a unique carbon nanotube-hafnium crystal structure will be formed.
Not to mention researchers like them, even the material calculation model from the Sichuan and Hai Materials Research Institute did not predict this.
After all, the initial addition of the hafnium oxide substrate with the help of the model was just to increase the strength of the carbon material.
It can only be said that supercomputers cannot predict complex reactions in the field of materials.
Or to put it another way, God is helping them!
Avoiding this topic, Zhao Guanggui swallowed and continued nervously and worriedly: "Judging from the test data, except for neutron irradiation, all other properties of this material should meet the requirements of the first wall material.
The rest depends on how it performs when faced with neutron irradiation."
The selection of first wall materials for controllable nuclear fusion reactors can be said to be one of the most complex problems of all, ranking in the top three.
The difficulty is no less than the control of high-temperature plasma turbulence and tritium self-sustainment.
As for which of these three problems is more difficult, it depends on different people's opinions. Anyway, they are not easy to solve.
Xu Chuan thought for a while and said: "Carbon and silicon can maintain strong stability and integrity when faced with neutron irradiation. The only worry lies in this new type of carbon nanotube hafnium crystal structure.
How stable is it when faced with neutron irradiation?"
"Although it maintains its stability in the face of the impact of high-energy deuterium and tritium particles and strong radiation, the decay properties of hafnium metal make me a little worried. It may not be able to hold up when faced with neutron irradiation.
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Thinking that it might not be possible to talk about the materials that others had worked so hard to create, Xu Chuan quickly added: "Of course, these are just theoretical analyzes I did based on the data. The specific results still need to be seen from the experimental data."
"After the Dawning Device is repaired in the next year, let's test materials like yours first. Maybe we'll be really lucky this time?"
"If the test results are excellent, construction of the demonstration reactor can begin."
Hearing this, Zhao Guanggui's breathing became much faster.
This chapter is not over yet, please click on the next page to continue reading! If he can make a key contribution in the construction of the demonstration reactor, there should be no pressure to be elected as an academician in the coming year.
But after thinking about it, he quickly calmed down and swallowed nervously.
The neutron irradiation experiment is the real key. If this cannot be maintained, all previous efforts and excellent performance will be in vain.
And what the old man in front of me said is actually not a problem.
Hafnium is the main additive element in heat-resistant alloy materials, while hafnium dioxide is a ceramic material with a wide bandgap and high dielectric constant, which is why they chose it as an additive and catalyst this time.
But hafnium has a big flaw when it comes to neutron irradiation.
That is, hafnium has a very friendly attitude towards neutrons. To put it simply, hafnium can absorb neutrons, and its efficiency is hundreds of times that of ordinary materials.
In a nuclear fission reactor, uranium serves as nuclear fuel, and the ideal material for the uranium rod sheath is a material with added hafnium metal.
Because hafnium has an extremely high absorption rate of neutrons, only a small amount of hafnium is needed to greatly reduce the transparency of neutrons released during nuclear fission.
From this point of view, I am afraid that there may be huge problems with the materials this time.
Thinking about it, Zhao Guanggui's smile became a little bitter, and he said: "Hafnium element has a very high absorption rate of neutrons. Zirconium alloy with added hafnium material is used for uranium rod protective sheaths."
"From this critical point of view, I am afraid that this material cannot pass neutron irradiation."
Xu Chuan smiled and said: "There is still a possibility, but I don't think it is big."
After a slight pause, he continued: "But we are not without hope. The hafnium element has an extremely high absorption rate of neutrons, but don't forget that it also has an almost twin brother metal element."
"Perhaps you can try zirconium metal. Zirconium and hafnium both belong to the vb group of the periodic table of chemical elements. Their chemical properties are very similar. They are two metal types that coexist together in nature."
"Perhaps you can try using zirconium oxide as additives and catalysts. If my guess is correct, this should be feasible."
Hearing this, Zhao Guanggui's eyes suddenly brightened, and he quickly continued: "The most important thing is that the absorption rate of zirconium for neutrons is extremely low. In zirconium with sufficient purity, neutrons can easily penetrate it."
Xu Chuan smiled and said: "Yes, the absorption rate of zirconium nuclei for neutrons is very low. The only problem is that it can absorb hydrogen. In the same way, the isotopes of hydrogen, deuterium and tritium, will also be absorbed."
"However, as an additive, its amount is not very large. A slight loss of deuterium and tritium is acceptable in exchange for the stability of the first wall."
Zhao Guanggui nodded quickly and said: "I will go back and prepare the experiment again!"
p: I went to get the MRI results in the morning. There is only one update today and two updates tomorrow.