Chapter 522: Take an unusual step

With that sketch, Chief Engineer Wang left the STAR Imaging Research Institute and returned to the headquarters of the Nuclear Industry Group in Shangjing that day. He contacted the experts in the field of magnetic fluid power generation in the Engineering Academy. The feasibility of the application on the controlled fusion device was discussed.
However, although the team was gone, the nuclear industry group's working group remained in Jinling, and they continued to communicate with the researchers of the STAR Imaging Research Institute on technical issues.
At the same time, the experiment of the STAR device did not stop there.
After receiving sufficient funding guarantees, the institute was almost extravagant to conduct experiments every three days, using hydrogen and helium as research objects, and observing the various complex physical properties of the plasma in the stellarator.
Furthermore, in order to collect valuable data, Lu Zhou even ordered 1mg of valuable deuterium / tritium mixture to be injected into the reaction chamber, and conducted a test ignition at the risk of damaging the first wall material.
In fact, this experiment did cause some damage to the STAR device, but fortunately, the damage is still in the repairable category. Even so, the entire unit must not be shut down for one month.
Of course, although the price is high, the returns are also quite generous.
They not only verified the feasibility of the technology to realize the fusion reaction ignition, but also obtained a lithium sheet bombarded by a neutron beam carrying energy.
Especially for the latter, its scientific research value cannot be converted by money.
In China, it is probably only them who can do such a luxurious experiment.
At this moment, this hard-won lithium metal sheet is quietly lying in a specially treated oxygen-free glass slide, and the worker wearing protective clothing is placed under a scanning electron microscope to observe.
In a laboratory isolated from the outside, Lu Zhou and other researchers standing in front of the computer saw the data and pictures collected from the scanning electron microscope on the screen.
As they expected, the originally regular metal surface was now full of scars.
Through the detection of the infrared spectrometer, traces of residual helium and thorium can even be observed in the tortuous channels.
Fortunately, this shows that the neutron beam carrying energy did react with 63Li, and they successfully recovered a part of plutonium in the experiment.
As for the helplessness ...
They are facing too many problems, and they can't finish talking in a few words.
Looking at the image on the computer screen, Professor Li Changxia sighed softly.
"I bet this thing will break if you touch it lightly."
"Don't bet, even if it hasn't been bombarded by a neutron beam, this stuff can't be as strong." Staring at the hard-won data on the computer screen, Lu Zhou said casually.
Sheng Xianfu shook his head: "It's not just a matter of radiation damage, but the tritium production ratio is too low. And the most critical problem is not in the recovery itself. The energy carried by the neutron beam is too high, often not on the surface The 63Li reacted, but scrambled inside the cladding material. Even if the voxels we needed were left in the material, it couldn't be released at all. "
The neutron carrying energy is like a cannonball, and all the metal keys in front of it are as vulnerable as toys.
Moreover, the neutron penetrating the first wall is not just as simple as making a hole in the first wall. It will form a cavity inside the first wall material like a balloon, and eventually lead to the entirety of the first wall material. Swelling, embrittlement, and even surface material fall off, causing serious accidents.
This is also one of the main reasons why the fission reactor cladding material cannot be directly used in the fusion reactor.
In terms of resistance to radiation damage, the two materials differ by two orders of magnitude.
Until now, their research has entered an unknown area, and this also means that there is no previous experience to refer to. What to do next and how to solve these problems depends on them to think for themselves.
After thinking for a while, Professor Li Changxia tried to propose: "How about switching to molybdenum for structural materials?"
"Molybdenum doesn't work," he immediately rejected the proposal, and Lu Zhou shook his head. "Molybdenum has good heat resistance, but it will change to radioactive elements under neutron radiation."
Another researcher went on to suggest: "What about tungsten? Tungsten has good heat resistance. The products of transmutation are thorium and thorium, and there is no radioactive problem!"
This time, I do n’t need to talk about Lu Zhou. Professor Li Changxia shook his head.
A common question. The heat resistance of tungsten is no problem, but the plasticity is too poor. Thermal stress will cause the surface of the material to crack ... I visited in the DIIID laboratory. When I was studying, there was a special report there that dealt specifically with this issue. In short, using tungsten is impossible. "
There was silence again in the laboratory.
At this time, Lu Zhou, who had been staring intently at the data on the screen, suddenly spoke.
"If we can't block the neutron beams inside, why don't we consider putting them in?"
"Let it go?" Sheng Xianfu gave a slight slump, then shook his head with a smile, "How do we recover the neutrons produced by the reaction?"
Recovery of neutrons generated in DT fusion reactions is a key part of the entire nuclear fusion reactor technology. After all, the price of tritium resources is not only tens of thousands of times that of deuterium. Not only is it sold for grams, the cost of one gram is as high as 30,000 US dollars (17 Annual data).
If the neutrons generated by the reaction cannot be recovered, it will not only cause a large amount of energy loss, but also cause the reactor to "shut down" due to the loss of plutonium.
In an ideal fusion reactor, whether it is tritium or neutron, it should be preserved as an intermediate product. The final waste produced is only helium and heat.
Therefore, it is impossible to let go of the neutron, and you have to leave it behind.
Hearing Sheng Xianfu's question, Lu Zhou smiled slightly and continued.
"Losting them is not the same as letting them go. In theory, no matter how we design the structure of the first wall, we cannot avoid the destruction of the metal bonds by the neutron beam. However, the self-healing ability of some metals is too poor, and it is more difficult. The problem of transmutation. "
"So why don't we set the first wall as a material that allows neutrons to pass and have strong self-healing ability, and then use liquid 63 lithium to recover neutrons behind the first wall. As for the other side of 63 lithium, use A beryllium metal coating that reflects neutrons that penetrate the liquid lithium layer without reacting. "
This design is equivalent to sandwiching liquid lithium between the first wall and beryllium.
Sheng Xianfu lowered his head for a while and thought that this method seemed feasible, but he always felt that there were problems everywhere.
After thinking about it for a while, he picked out the two most obvious ones from the problems that he could think of.
"But where do you say this material that allows neutrons to pass and has strong self-healing ability? Even after moving the lithium material to the first wall material, we still cannot solve the damage caused by neutron radiation to the structural materials. . And, as you said, to recover radon after the first wall, how can we move it back to the reactor from behind the first wall? "
After hearing these two problems, Lu Zhou smiled lightly and said, "The second problem is actually not difficult to solve. At the operating temperature of liquid lithium, both halogen and helium exist in gaseous form, and both are Incompatible with each other. "
"We only need to apply a weak upward force to the entire liquid lithium neutron recovery system to carry the generated halogen over the entire system."
"Then, we just need to recover the exhausted 'gas' above the entire system."
The generated plutonium and helium as exhaust gas are re-injected into the reaction chamber to be heated and ionized. As for how to remove helium from the reactor, this is how the diverter works.
As for whether to choose a water-cooled filter, a tungsten copper filter, or other filters, this time it depends on the specific needs to choose. Although this part of the technology is critical, it is not an insurmountable difficulty.
Having said that, Lu Zhou paused and continued, "As for the first question you said, such a material cannot be found in alloys. So, we simply discard the entire metal!"
When hearing this sentence, it was not only Sheng Xianfu who raised the question, including Professor Li Changxia, everyone in the laboratory froze.
Discard metal materials?
This……
This is too avant-garde, right?
"Metals are not used for structural materials?" Professor Li Changxia looked at Lu Zhou in surprise, "What's the use?"
Is it ceramic?
Although some research institutes have tried it this way, the effect is still reasonable, but fatally, the thermal conductivity of ceramics is really poor.
If the heat generated cannot be removed from the reactor, problems will eventually arise.
"Use carbon," Lu Zhou said in a certain tone after a pause, "or more accurately, use carbon fiber composites!"
This is not the way Lu Zhou came up with unexpected ideas. Before that, he had been thinking for a long time, even when he was chatting with Professor Kreiber at the Spiral Stone 7X Research Institute at the earliest.
The carbon nucleus is relatively stable, it is not easy to react with neutrons, and it can buffer the neutron beam, so that when the neutron beam is in contact with the liquid lithium layer, most neutron beams will not directly penetrate it. .
And the part of the energy reduced by the carbon fiber layer will be released in the form of thermal energy, and with its good thermal conductivity, it can also easily remove the heat generated inside the reactor.
As for the heat resistance, there is no problem at all.
When not in contact with air and oxidants, the carbon fiber material can withstand high temperatures of more than 3000 degrees, comparable to the melting point of tungsten, and fully meets the needs of the first wall material!
Looking around at the people in the laboratory, Lu Zhou said, "The low-activation metal material is completely removed from the first wall, and carbon fiber is used as the first wall material and the main structural material. The middle layer is filled with liquid lithium and the outer layer is used. Beryllium coating, reflecting neutrons. The shielding layer is covered with a mixture of paraffin and water and boron carbide and covered with nuclear power cement. In this way, we have every hope to solve the problem of tritium retention! "
As for what kind of carbon fiber composite materials to choose ~ EbookFREE.me ~ How to solve the problem of self-repair of carbon fiber composite materials, this subject will be studied by the Materials Research Institute of Jinling Institute of Advanced Research.
Although the problem is serious, Lu Zhou hopes to solve it!
Professor Li Changxia couldn't help but said, "This is too ..."
What he wanted to say was that it was incredible.
But this sentence was only half said, and was interrupted by Sheng Xianfu.
"No, maybe ... it's really promising!"
After interrupting Professor Li's words, Sheng Xianfu rubbed his chin with his index finger, and his eyes became brighter and brighter.
"I have reviewed relevant literature and replaced some austenitic steel and tungsten steel structures with carbon fiber. In the field of internationally controlled fusion, it is a technical route that is as promising as nanoceramics!"
"However, the carbon fiber composite material is used to completely replace the metal material as the main body of the structural material, and the decelerated neutron beam is placed on the outside of the cladding material to react with the liquid lithium. I have heard of these for the first time. "
I am afraid that the difficulty is not small, and it is not just a problem of the carbon fiber composite material itself. For example in temperature control. The working temperature of the carbon fiber material on the first wall is about 3000 degrees, while the boiling point of lithium metal is only 1340 degrees.
If the heat cannot be removed in a timely manner, the liquid lithium in the entire "liquid lithium neutron recovery system" is at risk of being gasified. It may be involved in the reactor with the plutonium-helium mixture generated by the reaction. The reactor blew up ...
There is also the problem of volume change caused by the solidification of liquid lithium when the reactor is stopped ...
But as Lu Zhou said, this idea seems feasible.
At least, it's worth a try!
(I went out to gather materials yesterday.)
Genius in one second: m.