Great Country Academician

After Zhao Guanggui left, Xu Chuan returned his attention to his previous research on magnetic surface tearing, twisting modes, and plasma magnetic islands.

Glancing at the computer, the model that was running in the supercomputing center before, except for a part of the data, but most of it is still being processed.

Even with the assistance of supercomputing, it is not so easy to simulate the tearing effect of the magnetic surface produced during the high-temperature and high-density deuterium-tritium plasma flow fusion process.

After all, the amount of data is too large.

After slightly checking the operation of the model, and after confirming that there was nothing wrong, Xu Chuan picked up the data that Zhao Guanggui had brought over on the table and read it again.

He is very interested in this new material that has not yet been named.

After all, the value of a composite material that can withstand a high temperature of 3,500 degrees is quite amazing.

Even if it doesn't necessarily apply to the first wall material of controllable nuclear fusion, it still has enough value.

In addition to being commonly used as high-temperature refractory materials such as abrasives, casting molds, nozzles, heat-resistant bricks, etc., heat-resistant materials can also be used as structural components of top-level technologies such as fighter jets and rockets.

For example, the space shuttle of the United States, the outermost material is a layer of high temperature resistant and heat insulating ceramic material.

Of course, the material in front of us must not reach this level.

Because it has an important defect, when most of the materials are carbon nanomaterials, its high temperature resistance properties can only withstand high temperatures in a vacuum environment, and the use conditions are quite harsh.

This is no problem for controlled nuclear fusion, after all, the reactor chamber itself is in a vacuum state after operation.

But for aerospace, the problem is very big.

After all, the areas where most fighter jets, rockets, and space shuttles need to use high-temperature resistant materials are exposed to the air.

Such as aircraft engines, rockets, and space shuttle outer insulation materials.

Of course, if this new material is covered with a high-temperature-resistant and air-insulating coating, it should be applied to the engine.

It's just that the life of the coating is generally a big problem, especially in places where the working environment of fighter jet engines is extremely harsh.

If the characteristics of this new material can be optimized, and the carbon material inside can be optimized so that it can withstand high temperatures above 3,000 degrees in a conventional environment, then this new material will be of great value.

But this is not an easy task, at least in a short period of time, he can't find any good inspiration and ideas from the data in front of him.

Of course, this is just a incidental matter of hugging grass and beating rabbits.

Rather than optimizing the high temperature resistance of this new material in the air, what Xu Chuan wants to do is to see if he can use mathematics to calculate whether this new material can withstand neutron radiation.

It is not impossible to verify the radiation damage of a material when it is irradiated with neutrons through mathematical tools and models.

After all, it is too difficult to do neutron irradiation experiments with real swords and guns.

Not to mention other countries, in China, there are only a handful of places that have the ability and qualifications to conduct complete neutron irradiation experiments.

One is the Daya Bay nuclear fission power station, and the other is the spallation neutron source base in Dongguang.

The former uses neutrons emitted by nuclear fission itself to conduct irradiation experiments, while the latter uses high-current proton accelerators to accelerate protons to collide with metals such as tungsten and beryllium to produce neutrons, and then conduct neutron irradiation tests.

But no matter what it is, there is a considerable gap in the energy level from the neutrons produced by the real deuterium-tritium fusion.

Each deuterium-tritium nuclear fusion produces a neutron at 14.1 MeV, although in a large strong particle collider, 14.1 MeV is not a very high energy level.

But to produce neutrons of such a high energy level, there are almost no other ways except hydrogen bomb explosion and deuterium-tritium fusion.

This is one of the reasons why the first wall material is difficult to develop.

There is no way to do neutron irradiation experiments, but it is impossible not to research and develop the first wall material, so physicists, material scientists, and programmers worked together to come up with a "nuclear data processing program", which includes the "medium Sub-irradiation effects' measurement.

In fact, the principle is very simple. It uses the neutron radiation damage mechanism to make a phenomenological or big data prediction of the collision between the neutron beam and the target material.

Because the energy carried by different neutrons is different, for example, the high-energy neutrons in the deuterium-tritium fusion process will carry 14.1 Mev of energy, and how much damage it will cause to the target can be speculated.

After all, in the process of interaction between energy-carrying neutrons and target atoms, neutrons must first interact with a lattice atom (that is, collide), and then energy-carrying neutrons can transfer energy to this lattice atom, generating a KPA Collision atoms.

And whether this KPA collides with atoms, whether it will continue to leave the nucleus to collide with the next atom, and how much energy will be lost, these are all original records, which can be speculated.

It's just that this simulation method itself is only image-only, and the simulated data is more or less "a little bit" unreliable.

Referring to the phenomenological mathematical model he established for plasma turbulence, the first experiment was barely controlled for 45 minutes.

After obtaining accurate experimental data later, after targeted adjustment and optimization, the running time was pushed to more than two hours.

From this we can see how unreliable the only image model is.

But in terms of neutron irradiation experiments, there is no other way.

Although the simulation results are not necessarily reliable. But at least, it is much better to use the phenomenological model to exclude some materials first, and then to do specific experiments rather than directly.

After all, the anti-neutron radiation performance testing experiment is too precious and difficult to do, especially the high-energy neutron radiation experiment is even more difficult.

After integrating the material data in his hand, Xu Chuan entered it into the computer.

Although the material is newly developed, elements such as carbon, silicon carbide, and hafnium oxide are all conventional substances in neutron irradiation experiments.

The only unstable point lies in the unique arrangement of the carbon nanotube hafnium crystal structure. There is no relevant empirical data for this material in the past. Xu Chuan can only make a guess based on the conventional radiation test data in the data.

After thinking about it, Xu Chuan pulled out a stack of A4 papers from the drawer.

The black signature pen in his hand stayed on avoidance, and after thinking for a while, he did it.

"Without considering the crystal effect and the interaction potential between atoms, it is calculated according to classical mechanics. Suppose: the incident neutron mass M1, the energy Eo; the resting target atomic mass M2"

"Then the calculation formula of DPA can be expressed as DPA=(∫σpx(E)(E)ΦE)t(6), and obx(E) is the off-site cross-section of the incident particle with energy E, and t is the irradiation time. "

"Derived: σpx(E) = 2∑i∫Tmax, Td vd(T).dσd(T, E)/dT DT"

"Vd(T) = (0.8/2Td)·Tdam"

The line-by-line formula was written by Xu Chuan. If the Lindhard-Robinson model is used to calculate the DPA under neutron irradiation conditions, it is enough for him to make a model and input data into it.

However, the unique arrangement of carbon nanotubes and hafnium crystals requires him to re-consider some variables related to materials, especially the speed of hafnium’s neutron absorption rate, which needs to be calculated.

Instead of modifying the Lindhard-Robinson model and making a new one, he might as well write the calculation directly.

Anyway, it's not that difficult.

At least, for him it was.

For him, troubles that can be solved by mathematics are not troubles.

I don't know how much time has passed. When Xu Chuan put down the black signature pen in his hand, there were lines of functions on a piece of manuscript paper specially used to list the calculation result data.

[PWR DPA, dpa/s=2.718E-08]

[PWR He, appm/s=6.172E-09]

[HTTR DPA, dpa/s=2.602E-09]

【HTTR He】

Picking up the manuscript paper on the table and looking at the results on it, Xu Chuan let out a long sigh of relief and couldn't help shaking his head.

From the calculation results of the simulation, it is obvious that the performance of this new material is not excellent when faced with the numerical calculation of simulated neutron irradiation.

Even, it is not as good as austenitic steel.

As for the key, it should lie in the additive hafnium oxide.

After all, for a material resistant to neutron radiation, not all the energy of incident particles is transferred to the struck atoms, resulting in radiation damage to the material.

The energy of neutrons is transferred to the inside of the atom, causing ionization and electron excitation effects, but it will not last in the material, only part of the energy is transferred to the nucleus, resulting in secondary dislocation and the formation of point defects. This part of the energy is called radiation damage energy .

To put it simply, neutrons collide with material atoms. If the energy transferred to the lattice atom exceeds a certain minimum threshold energy, the atom will leave its normal position in the lattice and leave a vacancy in the lattice. Not to mention, the knocked out atoms will continue to form multiple collisions in the material.

Just like playing billiards, you can do miracles with great force. When you hit the cue ball with infinite force, the cue ball will transmit the force to other child balls.

And as long as these balls run on the table for long enough, they will always fall into the pocket.

Of course, this is only theoretically feasible. In fact, the billiard ball will stop for various reasons, or it will not fall into the bag because of the angle problem.

The same is true for neutrons. Xu Chuan wants these neutrons, and the bag is equivalent to the neutrons passing through the first wall material smoothly, and those at wrong angles will cause radiation damage

The hafnium element has a very high absorption rate of neutrons, and in this process, the initial value will increase significantly, which in turn leads to the amplification of the damage caused by the neutron irradiation effect.

This is a fatal flaw for the first wall material.

Although the data calculated by the Lindhard-Robinson calculation formula is phenomenological, it can generally reflect the performance of materials in terms of resistance to neutron radiation.

However, although the calculation result was terrible, Xu Chuan was not discouraged.

On the contrary, there was a hint of excitement in his eyes.

Because this calculation result confirmed his previous speculation.

Hafnium oxide as an additive in the material doesn't work, so what about zirconia?

Zirconium is not much different from hafnium in terms of chemical properties, but it can be described as two extremes in terms of neutron absorption rate.

Hafnium has an extremely affinity for neutrons, and its absorption rate is more than 500 times that of zirconium.

If zirconia can replace hafnium oxide as an additive to reconstruct this new type of carbon composite material, maybe the first wall material really has a place.

Looking at the data on the manuscript paper, Xu Chuan's eyes danced with joy and excitement.

Now, we just need to wait for Zhao Guanggui and the others to replace hafnium oxide with zirconium oxide to resynthesize the material again. I hope everything goes well.

PS: there will be another chapter later