The Science Fiction World of Xueba

Pang Xuelin smiled and shook his head, but he had no intention of talking to Baker.

At this stage of physics research, it can only be a castle in the air, without experimental verification, no matter how big the brain is, it is meaningless.

Moreover, in these papers, he did not find a few new theories that could avoid sophon interference experimentally, let alone a way to shield sophon interference.

But Pang Xuelin is also very clear that there is no rush for this kind of thing.

According to his plan, before promulgating the law of the dark forest, it is best to find a way to shield sophons. If he can't find it, as long as his plan can be implemented smoothly, the overall impact on the future development of mankind will not be great.

It took nearly half a month for Pang Xuelin to have a general understanding of the technological progress of the past five years.

In general, aerospace has made rapid progress, but it is basically the result of piling up resources.

Human spaceflight activities still cannot get rid of chemical rocket power, and in the foreseeable future, there is no other way to replace chemical rocket power.

In other fields, the transistor density of integrated circuits has quadrupled compared to five years ago, but it is already approaching the limit of Moore's Law.

And because of the blockade of sophons, there is no need to think about quantum computers. Currently, scientists are considering replacing the original silicon-based chips with carbon-based chips.

Biomedicine, new energy, modern agricultural technology and other fields even show signs of retrogression.

In particular, new energy has suffered a devastating blow.

At present, countries have generally no longer considered issues such as climate change and global warming, and have begun to turn a blind eye to environmental pollution. Those expensive solar and wind power are no longer favored by governments, and low-cost thermal power generation Power stations and nuclear power plants have become the first choice for power sources.

Those solar energy, wind energy and other enterprises that had developed well have closed down one after another in recent years, and only a few are still persisting, but they will not last long.

In the field of agriculture, the climate anomalies in the past few years have shown signs of intensifying, but they have not yet had a particularly large impact on agricultural production.

Pang Xuelin estimates that this influence will not be evident until at least twenty or even thirty years later.

On this day, Pang Xuelin handed a list to Cheng Xin and said, "Notify the people on the list,

Three days later, there will be a meeting at the Xinghuan Institute for Advanced Study. Some of them are on business trips, so they must come back in three days! "

Cheng Xin was slightly taken aback, glanced at the names on the list, nodded and said, "Okay, I'll notify you right away."

What Pang Xuelin wanted Cheng Xin to inform were experts in the fields of nuclear physics and materials recruited by Kanter in recent years at the Transwarp Institute for Advanced Study.

In the past five years, international research on nuclear fusion has mainly focused on ITeR-based multinational cooperation. Compared with the multilateral cooperation projects before the Three-Body Crisis, the efficiency of ITeR is now several times higher. The various technical indicators have also increased a lot.

This also led to the unsatisfactory progress of ITeR even after five years.

Pang Xuelin is going to start anew and build a fusion reaction experimental reactor in Xinghuan City.

Controlled nuclear fusion is known as the ultimate energy source for mankind. One liter of seawater contains about 30 mg of deuterium. The energy released through fusion reaction is equivalent to the energy of more than 300 liters of gasoline, and the reaction products are non-radioactive.

In other words, 1 liter of seawater can produce energy equivalent to 300 liters of gasoline. A 1 million kw nuclear fusion power plant consumes only 304kg of deuterium per year. It is estimated that there are 4.5 billion tons of deuterium naturally present in seawater. The deuterium in seawater is converted into energy through nuclear fusion. According to the current world energy consumption level, it is enough to meet the energy demand of human beings for billions of years in the future.

Not to mention, there is a surprising amount of helium reserves suitable for second-generation fusion reactors on the moon.

However, in order to achieve a controllable nuclear fusion reaction, there are naturally many technical difficulties.

First, tens of millions or even hundreds of millions of degrees of high temperature, at this temperature some nuclei in the plasma gas may undergo fusion reactions, the higher the temperature, the faster the fusion reaction will proceed.

The second is sufficient confinement, that is, to confine the plasma at high temperature in a certain area and keep it for a sufficient time to make it fully fused.

Third, the rather low density. The plasma gas at high temperature has a very high pressure, so the gas in the container should be pumped to a considerable vacuum, so that the number of particles per unit volume cannot exceed 10 to the 15th power, which is equivalent to tens of thousands of gas density at room temperature one.

Fourth, ensure self-sustainability. The instability of the plasma at high temperature means that it can only be confined for a short time. In order to make a sufficient amount of plasma gas undergo fusion reaction and be self-sustaining, there must be a requirement between the density of the plasma gas participating in the reaction and the reliable constraint time for it, that is, the Lawson condition. For example, the conditions for realizing the deuterium-tritium fusion reaction are: the plasma temperature reaches 200 million degrees, the particle number density reaches 10^20m^-3, and the energy confinement time exceeds 1s.

The fifth, and the most difficult and most important point, is to make nuclear materials for fusion reactors.

At present, the first three technical difficulties have been basically overcome. If the ITeR project goes well, the fourth problem is expected to be solved in the next two decades, and only the fifth problem is still far away.

Fermi once said that the success or failure of nuclear technology depends on the behavior of materials in the reactor under the intense radiation field.

Although this sentence is appropriate for fission reactors, it is also valid for fusion reactors. To some extent, it is the key to the success of controllable nuclear fusion.

In a commercial Tokamak fusion reactor, the first wall material, that is, the layer directly facing the plasma, needs to meet the following stringent requirements:

The first is low tritium retention.

Compared with the legendary helium fusion, the most easily controlled fusion reaction is the deuterium-tritium reaction.

However, tritium (T) has a short half-life and there is no natural tritium. Artificial production is almost impossible, hundreds of millions of dollars per kilogram, there is still a price but no market. Therefore, the tritium in the fusion reactor needs to be recycled.

At present, the main method in the scientific community is to use the multiplied neutrons to react with lithium, and then recover tritium, so that tritium becomes a catalyst-like existence.

However, the current consumption/multiplication ratio of tritium is very low (1:1.05 in memory, may be wrong), so the tritium dissipated in each link must be strictly controlled. Among them, because the first wall is directly in contact with the plasma, it is regarded as a large tritium retention, which needs to be strictly controlled. Otherwise, the more tritium is used, the less it will directly cause the plasma to go out and shut down the reactor.

The second is the ability to resist neutron radiation.

Each deuterium-tritium fusion will produce a neutron with an energy of 14meV. These high-energy neutrons can easily break the metal bonds in the first wall material, resulting in a large number of defects, causing radiation swelling, embrittlement, creep and other problems, making the material Totally unusable.

The neutron dose to the first wall of a commercial fusion reactor is expected to exceed 100dpa, while the dose of a fission reactor is on the order of 1dpa, so it is impossible for existing fission reactor materials to be directly used in a fusion reactor.

Third, anti-plasma radiation.

At present, the boundary of magnetic confinement is not ideal, and there is still a lot of room for improvement in plasma turbulence control.

Therefore, the first wall, especially the divertor armor, is still subject to high-flux deuterium/tritium/helium plasma impact. After these plasmas are bombarded into the material, they will gather on the surface, causing the surface to bubble and peel off.

On the one hand, the surface integrity of the material is destroyed, and on the other hand, the falling debris enters the plasma, which will also cause the plasma to burst.

Fourth, the problem of low activation.

Under the bombardment of neutrons, many elements undergo nuclear reactions and transmutation into other nuclides. Some nuclides are unstable and will continue to emit radiation through further decay. In this way, the advantage of the non-radiation pollution product of the fusion reaction is gone, so the materials used as the first wall are all low-activation materials, that is, elements that are still stable and do not decay after transmutation.

For example, at the beginning, people planned to use metal molybdenum as the first wall material, but later found that the transmutation products were too difficult to handle due to radiation, and now they are gradually replaced by metal tungsten.

Fifth, high temperature resistance and thermal shock resistance.

The working temperature of the first wall of a commercial fusion reactor is above 1,000°C, and it can reach 2,000-3,000°C when the plasma is shattered. Materials with low melting points such as steel and copper are directly eliminated.

In addition, the task of the first wall is to export heat energy, and ceramic materials with high melting point but poor thermal conductivity are basically eliminated.

The currently promising candidate material, metal tungsten, has a melting point of 3400. However, tungsten also has the disadvantage of poor plasticity. Under the thermal shock of plasma collapse, the thermal stress often causes the surface of the material to crack.

It is already very difficult to satisfy one of the above conditions, and materials that satisfy all the conditions do not exist yet.

Because of this, controllable nuclear fusion is considered to be the most challenging mega-science project encountered in the history of human science and technology.

But for Pang Xuelin, these are not problems.

In the world of Wandering Earth, human beings have already realized heavy nuclear fusion technology, and light nuclear fusion is of course not a problem.

In the world of Wandering Earth back then, Pang Xuelin also specially memorized the technical route for the realization of controllable nuclear fusion.

Although he did not have a detailed understanding of the specific technical details, he is very clear about the key nodes and technical directions for realizing controllable nuclear fusion.

He originally thought that it might come in handy when he returned to the real world.

But he soon realized that in the real world, he had no way of gaining control over the development of controlled nuclear fusion.

And even if he knows the direction of technological development, with the level of technological development in the real world, if he wants to truly manufacture a fusion reactor that can be operated commercially, the cycle will be at least ten years.

So in the real world, he gives priority to making breakthroughs in the fields of carbon-based chips and high-density energy storage batteries, and will only develop controllable nuclear fusion when he has the opportunity in the future.

But in Three-Body World, none of this is a problem.

What's more, Pang Xuelin has to deliberately control the realization time of controllable nuclear fusion. He must take out controllable nuclear fusion after the arrival of the big trough, and the power of all countries has weakened to the point where he is unable to control the global situation, so as to realize the benefits maximize.