After receiving the data from Zhao Guanggui's hand, Xu Chuan read it carefully.

The problem of irradiation of high-energy neutron beams has always been a problem of the century that has been studied all over the world.

The most troublesome thing about high-energy neutrons is not the radiation they carry, but the fact that they can collide with the nuclei of different elements.

When neutrons collide with various atomic nuclei, the phenomenon of "neutron excitation" occurs, producing unstable isotopes, making matter radioactive and damaging the structure of matter.

To put it simply, some of the original materials are a family of four, two neutrons + two protons form a loving family.

Then the foreign high-energy neutron hit the nucleus of the atom and forcibly inserted it like a little three, and then, the family was broken and imperfect.

At present, the scientific community deals with the problem of neutron irradiation, and generally uses neutron moderation materials and slow neutron absorbing substances to intercept neutron irradiation.

Among them, neutron moderation materials are divided into two types: heavy and light elements, and the heavy elements are mainly common metal materials such as lead, tungsten, and barium.

They block fast neutrons, reducing the energy of the neutron beam and making them slow neutrons.

Neutrons that have been moderated by heavy elements need to be further moderated by light elements before they can be absorbed by slow neutron absorbing substances.

This step is mainly carried out with materials high in polygen, such as water, paraffin, polyethylene, etc.

After light element treatment, slow neutrons can be completely absorbed and eliminated by materials containing lithium or boron, such as lithium fluoride, lithium bromide, boron oxide and other materials.

Otherwise, even the slowest neutron can be destructive to materials or human organisms.

Dealing with neutrons alone is so cumbersome, and the first wall material of controlled nuclear fusion also has to withstand various problems such as high temperatures, deuterium-tritium high-energy particles, gamma rays, ion contamination, etc.

Even though materials built through atomic circulation technology and radiation gaps have the ability to absorb radiation and rays, it is difficult to find a material that allows neutrons to pass through, faces high temperatures, and remains self-healing.

This is especially true when metallic materials are excluded.

After all, there are not many non-metallic materials that can withstand thousands of degrees of high temperatures.

Ceramic materials are counted as one, carbon materials are counted as one (graphite, diamond are also carbon materials), and composite materials are also counted, but there are many types of this, and only some of them are available.

At present, there are non-metallic materials that can withstand high temperatures of more than 3,000 degrees Celsius.

As the first wall material, these materials basically have their own defects.

Therefore, when he heard Professor Zhao say that the new materials they developed may have the potential to be applied to the first wall materials, Xu Chuan was quite surprised in his heart.

After all, it has only been two or three months since he officially gave 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 mathematical model of material calculation from the Chuanhai Materials Research Institute, this speed is a little too fast.

It took more than ten minutes for Xu Chuan to read the data in his hand completely.

Judging from the information in hand, Zhao Guanggui and the others developed a carbon nanotube + carbon fiber reinforced silicon carbide + hafnium oxide matrix composite.

In terms of properties, it is similar to high-temperature resistant composite ceramic materials, and has the properties of most temperature-resistant and high-temperature ceramic materials.

The difference is that because the main structure is carbon nanotubes and carbon fiber reinforced silicon carbide materials, the thermal conductivity has been greatly improved compared with ceramic materials.

The thermal conductivity of ordinary ceramic materials is between 0.5-1W/m·K, while the thermal conductivity of this composite material is 52.11W/m·K, which exceeds the 40W/m·K of graphite.

Of course, the thermal conductivity of 50W/m·K is nothing in some special ceramics.

For example, the thermal conductivity of silicon carbide (SiC) ceramic substrates can reach 120-490 W/m·K, and the thermal conductivity of aluminum nitride (AlN) ceramic substrates can reach 170-230 W/mK.

These two ceramic substrates are considered to have the best thermal conductivity among ceramic substrates, but they are not high temperature resistant.

The vast majority of silicon carbide will melt after more than 1600 degrees, while aluminum nitride can be stabilized to 2200 degrees at most, but it still cannot meet the requirements of 3000 degrees.

Of course, if the temperature is not up to standard, the temperature can still be maintained through the water cooling equipment, and 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 support bond, and the damage to the metal bond by neutron irradiation is particularly obvious.

As for carbon nanotube materials and carbon fiber materials, although they can withstand temperatures of more than 3,000 degrees in an oxygen-free environment, the absorption of deuterium-tritium raw materials by carbon materials alone is too serious.

As a result, it is difficult for pure carbon materials, such as graphene and carbon nanotubes, to be applied to the first wall.

As for the reinforced composite material researched by Zhao Guanggui, it can withstand ultra-high temperatures of more than 3,400 degrees Celsius in an oxygen-free environment.

This value, if compared in pure metals, is comparable to tungsten.

If it is an alloy, there is still some distance from the melting point of 4215 degrees Celsius of pentacarbide tetratantalum hafnium (Ta4HfC5).

However, it is enough to apply it to the first wall of a controlled nuclear fusion reactor.

The most important thing is the absorption of deuterium-tritium raw materials, which can be seen from the test results, this composite material, unless it carries high-energy deuterium-tritium ions uncontrollably hit the surface of the material, it will not combine and react with the material itself.

Putting the document in his hand on the table, Xu Chuan looked up at Zhao Guanggui and asked with interest:

"Interestingly, from the cross-sectional electron microscopy of the material, it seems that the atomic cycle technology and the radiation gap structure led to the combination of carbon nanotubes and the hafnium oxide substrate, and the chemical bonds of the carbon nanotubes replaced the oxidation bonds of the hafnium oxide substrate, forming a unique sequence of carbon nanotubes-hafnium crystal structure."

"And this unique sequence 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-tritium ions."

"Is there a process done specifically for this?"

For him, with all the detailed data of a material in front of him, it is not difficult to determine where the core key points of the material are.

At present, this composite material is a carbon nanotube and hafnium crystal structure with a special structure, which he has never seen before.

Zhao Guanggui nodded and said, "I did the inspection, but the results are not ideal, we can't separate the crystal structure you said, and we can't reproduce this unique sort of carbon nanotube hafnium crystal structure with carbon nanotubes and hafnium oxide alone." ”

"So at present, only the detection data of this material can be obtained, and the crystal structure data of the core cannot be obtained."

After the test data of this material came out, some people in the research team came up with the same idea as Xu Chuan, speculating that this unique crystal structure was at work.

It's just that there is no way to separate this special structure in the future, and there is no way to confirm whether it is playing a core enhancing role.

Hearing this, Xu Chuan touched his chin and thought about it.

If it can't be separated, it's really impossible to judge, but it doesn't have a big impact, as long as the material can be used.

Judging from the test data, whether it is thermal conductivity, high temperature resistance, or strength, ordinary physical properties, it meets the needs of the first wall material.

Of course, the more critical point is not these ordinary properties, but the resistance to deuterium-tritium high-energy particle impact, gamma rays, ion pollution, and most importantly, anti-neutron irradiation and other high-energy areas.

The former is not a big problem, and the atomic cycle technology and the structure of the radiation gap have been verified.

There is also a test in the data data, although it is not complete, but it can also be glimpsed, which is quite excellent.

As for the latter, the latter has not yet been experimented.

Neutron irradiation experiments are not so easy to do.

Interested asked, "How did you come up with this material?" ”

From the materials in his hands, he saw traces of the two materials construction techniques, 'atomic cycle' and 'radiation gap zone'.

The most obvious is the peculiar crystal gap zone shown on the section structure diagram, which is the crystal structure used to absorb β radiation.

Hearing this question, Zhao Guanggui smiled a little embarrassedly and said, "Strictly speaking, the idea of this material is not actually something that I thought of alone. ”

"After you arranged for me to study carbon materials last time, I asked Professor Han Jin and Academician Peng to learn about the two technologies you developed: atomic cycle technology and radiation gap zone."

During the discussion, Professor Han Jin mentioned the radiant energy semiconductor conversion materials you developed when you were studying nuclear waste. Considering that the first wall will also face the problem of strong radiation, I think that some silicon carbide materials can be doped into carbon nanomaterials as impurities to make semiconductors, which can be used to derive the electrical energy of radiant heat conversion, so as to maintain the stability coefficient of the material itself to a certain extent. ”

"I did research from this route, and then with the help of the material model of the Chuanhai Materials Research Institute, I gradually added another hafnium oxide material as a reinforcing agent."

"Unexpectedly, hafnium oxide and carbon nanotubes, which are reinforcing agents, have undergone unexpected changes, and the two form a special crystal structure, which not only reduces the thermal conductivity of carbon materials, but also brings new changes and optimizes the shortcomings of carbon materials to absorb deuterium-tritium raw materials."

Hearing this, Xu Chuan was a little surprised and asked, "So it's a lucky accident?" ”

After a pause, he then smiled: "Of course, in materials science, luck is also part of strength. ”

Zhao Guanggui scratched his head a little embarrassed.

Indeed, this material development can be said to be completely unexpected, except for some empirical processes.

No one thought that when hafnium oxide is added to carbon materials as an additive, with the help of atomic cycle technology, a unique carbon nanotube and hafnium crystal structure will be formed.

Not to mention these researchers, even the material calculation model of the Chuanhai Materials Research Institute has not been speculated.

After all, the hafnium oxide substrate was added with the help of the model in the first place, just to increase the strength of the carbon material.

It can only be said that supercomputers cannot predict the complex reactions in the field of materials.

Or to put it another way, it's Heaven helping them!

Bypassing this topic, Zhao Guanggui swallowed his saliva, and continued with some nervousness and concern: "Judging from the test data, the other properties of this material except for neutron irradiation should meet the requirements of the first wall material." The rest depends on how well it performs in the face of neutron irradiation. ”

The choice of the first wall material for a controlled fusion reactor can be said to be one of the most complex of all problems, ranking among the top three.

The difficulty is no less than that of high-temperature plasma turbulence control and tritium self-sustaining.

As for which of these three problems is more difficult, it is up to everyone to comment. It's not a good trouble to solve anyway.

Xu Chuan thought for a moment and said: "Carbon and silicon can maintain strong stability and integrity in the face of neutron irradiation, the only concern is that this new type of carbon nanotube hafnium crystal structure, in the face of neutron irradiation, how stable it is." ”

"Although it maintains its stability in the face of high-energy deuterium-tritium particles and strong radiation, the decaying nature of hafnium metal makes me a little concerned that it may not be able to withstand neutron irradiation."

Thinking that the materials that others had worked so hard to make might not work, Xu Chuan quickly added: "Of course, these are just theoretical analyses I made based on data, and the specific results still need to look at the experimental data." ”

"After the Daybreak Device is repaired in the next year, we will test your material first, maybe we will be really lucky this time?"

"If the test results are good, the demonstration reactor can start construction."

Hearing this, Zhao Guanggui's breathing was also a lot shorter.

The construction of the demonstration reactor, if he can make a key contribution in this, there should be no pressure to be elected an academician next year.

But after thinking about it, he quickly calmed down again, and swallowed a little nervously.

Neutron irradiation experiments are the real key, and if you can't support this, all the previous efforts and all the excellent performance will be in vain.

And what the big guy in front of him said is actually no problem.

Hafnium is the main added element of 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, simply put, hafnium can absorb neutrons, and the efficiency is hundreds of times that of ordinary materials.

In nuclear fission reactors, uranium acts as nuclear fuel, and the ideal material for a uranium rod sheath is one with hafnium metal added.

Because hafnium has an extremely high absorption rate of neutrons, only a small amount of hafnium needs to be added to reduce the transparency of neutrons released during nuclear fission.

From this point of view, I am afraid that the material may be extremely problematic this time.

Thinking about it, Zhao Guanggui's smile became a little bitter, and he said: "The hafnium element has an extremely high absorption rate of neutrons, and the zirconium alloy with hafnium material is used for uranium rod protection jackets. ”

"From this key point, I'm afraid that this material will not pass neutron irradiation."

Xu Chuan smiled and said, "There is still a possibility, but I don't think it's big." ”

After a slight pause, he continued: "But we are not hopeless, the hafnium element has an extremely high absorption rate of neutrons, but don't forget that it also has a brother metal element that is almost twin. ”

"Maybe you can try zirconium metal, zirconium and hafnium both belong to the VB group of the periodic table of chemical elements, and the chemical properties are very similar, and they belong to two metal types that coexist together in nature."

"Maybe you can try using zirconia as an additive and catalyst, and if I'm right, it should work."

Hearing this, Zhao Guanggui's eyes suddenly brightened, and he quickly continued: "The most important thing is that zirconium has a very low absorption rate of neutrons, and in zirconium with sufficient purity, neutrons can easily penetrate the past." ”

Xu Chuan said with a smile: "That's right, the zirconium nucleus has a very low absorption rate of neutrons, and the only problem is that it can absorb hydrogen, and in the same way, deuterium tritium, an isotope of hydrogen, will also be absorbed." ”

"However, as an additive, the amount of it is not very large, and a slight loss of some deuterium tritium in exchange for the stability of the first wall is acceptable."

Zhao Guanggui nodded quickly and said, "I'll go back and prepare for the experiment again!" ”

PS: I went to get the MRI results in the morning, and there is only one shift today, and there will be a double shift tomorrow.