Great Power Heavy Industry: Rise

Chapter 104 Popular Science: Controlled Nuclear Fusion
(Readers who don’t like it or already know the relevant knowledge can skip this chapter directly)
Nuclear fusion is the fusion of two lighter nuclei into one heavier nucleus, releasing energy.

The easiest fusion reaction in nature is the fusion of deuterium and tritium, an isotope of hydrogen, which has been going on for 50 billion years in the sun.

Controllable nuclear fusion is commonly known as artificial sun, because the principle of the sun is nuclear fusion reaction.

Nuclear fusion reactions mainly rely on hydrogen isotopes. Nuclear fusion does not produce long-term and high-level nuclear radiation that occurs in nuclear fission. It does not produce nuclear waste, and of course does not produce greenhouse gases, and basically does not pollute the environment.

It is known that thermonuclear fusion begins with the explosion of a hydrogen bomb.Scientists hope to invent a device that can effectively control the process of "hydrogen bomb explosion" so that the energy can be continuously and stably output.

Nuclear energy includes two main forms of fission energy and fusion energy.

Fission energy is the huge energy released by the fission of atoms of heavy metal elements, which has been commercialized.

Because heavy metal elements such as uranium needed for fission are scarce on the earth, and conventional fission reactors will produce long-lived and highly radioactive nuclear waste, these factors limit the development of fission energy.

Another form of nuclear energy is fusion energy, which is not yet commercially available.

The ultimate source of energy on Earth, whether stored in the form of fossil fuels, wind, water, or plants and animals, is the sun.

Fossil fuels evolved from animals and plants millions of years ago, and the energy of animals and plants (whether it is today or in the past) ultimately comes from the solar energy stored in the photosynthesis of plants at the bottom of the food chain.

The wind is caused by the unevenness of heat and cold caused by the sun's heating of the atmosphere.

The potential energy of water power also depends on the heating of the sun to evaporate the water body at a low level, rise up, and then be "transported" to a higher position in the form of precipitation, thereby forming potential energy.

Therefore, no matter which energy source humans use, they are ultimately using solar energy, and the energy of the sun comes from nuclear fusion.

Therefore, if human beings have mastered the way to release the energy of nuclear fusion in an orderly manner, it is equivalent to mastering the energy source of the sun, and it is equal to mastering the endless fossil fuel, wind power and water power energy.

The view that some people advocated that modern industry will perish because there is no energy source has also gone bankrupt.

Therefore, the controllable nuclear fusion reactor deserves to be called "artificial sun".

my country is in the leading position in the technology of controllable nuclear fusion. The EAST reactor, which is about to start operation, is the first reactor in the world to meet the practical engineering standard. Not far away.

Noun: Tokamak device

The tokamak device is the core device of controlled nuclear fusion.

The biggest difficulty in controllable nuclear fusion lies in where to put the reactants that reach hundreds of millions of degrees Celsius during nuclear fusion?

So far, humans have not created any chemical structure that can withstand 1 degrees Celsius, let alone hundreds of millions of degrees Celsius.

This is the only reason why human beings have not been able to effectively obtain energy from nuclear fusion after 50 years since the one-shot hydrogen bomb was manufactured.

Human beings are very smart, and we cannot use chemical structures to solve problems, so we use physical experiments.

As early as 50 years ago, two theories of confining high-temperature reactants were produced.

One is inertial confinement. This method puts a few milligrams of deuterium and tritium mixture gas into a small ball with a diameter of about a few millimeters, and then injects a laser beam or particle beam uniformly from the outside, so that the inner layer of the sphere is squeezed inward. .

The gas in the ball is squeezed, the pressure rises, and the temperature rises sharply. When the temperature reaches the required ignition temperature, the gas in the ball explodes and generates a lot of heat.

Such explosions occur three or four times per second, and continue continuously, releasing energy that can reach the level of millions of kilowatts.

The other is magnetic confinement. Since atomic nuclei are positively charged, as long as the magnetic field is strong enough, you cannot escape.

If a ring-shaped magnetic field is established, then the atomic nucleus can only move along the direction of the magnetic field lines and in a spiral shape, and cannot escape the range where the reaction occurs.

And at a little distance outside the annular magnetic field, a large-scale heat exchange device can also be established (at this time, the energy of the reactant can only be transferred to the heat exchange body in the form of thermal radiation).

Then use a method that humans are already familiar with to convert heat energy into electrical energy.

In order to achieve magnetic confinement, a device that can generate a sufficiently strong annular magnetic field is needed. This device is called "Tokamak device" - TOKAMAK.

That is, it is an abbreviation composed of the prefixes of "ring", "vacuum", "magnetic" and "coil" in Russian.

As early as 1954, the world's first tokamak device was built at the Kurchatov Institute of Atomic Energy in the former Soviet Union.

It seems to be going well, right?

In fact, otherwise, in order to be put into practical use, the energy of the input device must be much smaller than the output energy. We call it the energy gain factor——Q value.

The tokamak device at that time was a very unstable thing. It has been in operation for more than ten years and has not obtained energy output.

It was not until 1970 that the former Soviet Union obtained actual energy output for the first time on the tokamak device that had been improved many times.

However, it can only be measured with the most advanced equipment at that time, and the Q value is about one billionth.

Don't underestimate this one-billionth, which has made the whole world see hope, so the whole world has been motivated by this to build their own large-scale tokamak devices one after another.

What is a "Super Tokamak Device"?

The core of the tokamak device is the magnetic field. To generate a magnetic field, a coil must be used and electricity must be applied. Where there is a coil, there is a wire, and where there is a wire, there is a resistance.

The closer the tokamak device is to practicality, the stronger the magnetic field is, and the larger the current is to pass through the wire.

At this time, the resistance in the wire appears, and the resistance reduces the efficiency of the coil, and at the same time restricts the passage of large currents, which cannot generate enough magnetic field.

The tokamak seems to be coming to an end.

Fortunately, the development of superconducting technology has made the Tokamak a turnaround. As long as the coil is made into a superconductor, the problem of large current and loss can be solved theoretically.

Thus, a tokamak device using superconducting coils was born, which is the super tokamak.

noun: stellarator
Stellarator is also a controllable nuclear fusion device using the principle of magnetic confinement.

This is a magnetic confinement fusion experimental device with a helical winding.

It consists of a closed tube and an external coil, the closed tube is straight, "racetrack" or curved in space.

A common stellarator has two or three pairs of spiral windings, the magnetic surface of the former is similar to an ellipse, and the latter is approximately triangular.

Adjacent helical windings are passed currents of equal magnitude and opposite directions, and after the magnetic field generated by the helical windings is synthesized with the longitudinal magnetic field, the magnetic field lines are rotated and transformed, thus confining the plasma without longitudinal current.

Let's put it this way, the tokamak looks like a swimming ring, and the stellarator looks like a loose headband, which is very irregular.

Personally, I think that the tokamak is a better choice for the commercial use of controllable fusion energy under the condition that the magnetic confinement can be guaranteed to be controllable and safe. The stellarator still needs to be observed.

(End of this chapter)