Can controlled nuclear fusion become a reality?

We live in an era of technological explosion, with new things appearing almost every day. However, among all the expected future technologies, the most anticipated is undoubtedly controlled nuclear fusion.

Why do humans pay so much attention to controlled nuclear fusion? Because this is a revolutionary technology that is different from other technologies. Its success will completely change our way of life and will bring human civilization into a new stage of development. Energy is the foundation of civilization development. The more advanced the civilization is, the greater the demand for energy. If the way of obtaining energy is not changed, it will be difficult for civilization to continue to move forward. Take the fossil energy used by humans now, for example. It is the key factor that restricts humans from moving towards the stars and the sea. Fossil energy is so heavy that a carrier rocket weighing more than 3,000 tons has a payload of only about 100 tons. In this way, how can we fly to the stars and the sea?

Controlled nuclear fusion is different. It is extremely efficient and very stable. If controlled nuclear fusion can be realized, not to mention the distant future, at least we can travel freely in the solar system, and the spaceships in science fiction movies will become a reality.

Another advantage of controlled nuclear fusion is that it is clean. Compared with the pollution caused by fossil fuels, nuclear energy is undoubtedly clean. However, traditional controlled nuclear fission still produces a certain amount of radioactive waste, and once a nuclear leak occurs, it may cause serious nuclear pollution to the surrounding areas. But controlled nuclear fusion is different. It can react stably under natural conditions, and there is no risk of radioactive waste or nuclear leak. Controlled nuclear fusion is so good, what is its principle?

Simply put, controlled nuclear fusion is to let two light atoms collide under high temperature and high pressure environment to aggregate into a heavy atom. In this process, mass loss will occur, and the lost mass will be released in the form of energy.

From the mass-energy equation, we know that energy equals mass multiplied by the square of the speed of light, so a small loss of mass will be converted into huge energy. Specifically, what is the raw material needed for controlled nuclear fusion? Some people say it is helium-3. Indeed, deuterium and helium-3 can undergo nuclear fusion reactions, and there are abundant helium-3 resources on the moon, but the problem is that the technical difficulty of this reaction is relatively high, belonging to the second generation of nuclear fusion. What we are studying now is the first generation of nuclear fusion with relatively low technical difficulty, and the raw materials used are two isotopes of hydrogen, deuterium and tritium.

Are deuterium and tritium abundant on Earth?

Deuterium is very abundant. We know that what the blue planet Earth lacks the least is sea water. 71% of the Earth's surface is covered by oceans, and each liter of sea water contains 0.03 grams of deuterium. In total, there are as much as 40 trillion tons of deuterium in the Earth's oceans. If it is only used for controlled nuclear fusion reactions, then it can be said that it is inexhaustible.

Unlike deuterium, tritium is very rare on Earth. Although tritium is an isotope of hydrogen, it is a radioactive element, and the half-life of this radioactive element is very short, only 12.43 years. Therefore, even if there is tritium in nature, it will quickly decay into other substances and cannot be preserved for a long time. There are almost no conditions in nature for the natural synthesis of tritium.

Tritium is so scarce on Earth, and it is indispensable for controlled nuclear fusion. What can we do? We can only synthesize it artificially.

In principle, it is not too difficult to synthesize tritium. You only need to bombard lithium with neutrons to obtain it. In reality, if you want to make synthetic tritium, you can use gas-liquid catalytic exchange technology and special electrolysis technology. In fact, it is not difficult to artificially synthesize tritium. The difficulty lies in consumption and cost. The purpose of studying controlled nuclear fusion is to obtain energy, and the process of making tritium must consume energy, and the later confined fusion reaction also consumes energy. So can consumption and output be proportional? Although there are many technologies for artificially synthesizing tritium, the cost is very high, and it is still difficult to mass produce. This is also a difficulty faced in the process of controlled nuclear fusion research.

In addition to obtaining raw materials, there are many difficulties facing controlled nuclear fusion.

The reason why the sun can emit light and heat is because of the nuclear fusion reaction inside it, so controlled nuclear fusion is also called the "little sun". But unlike the sun, the pressure inside the sun is very high, but such a huge pressure cannot be generated on the earth, so a higher temperature is required to promote the fusion reaction. This temperature has far exceeded the melting point of all known materials. So what can be used to support the fusion reaction? The current research direction is mainly magnetic field confinement. It is conceivable that this research road is full of thorns. Some scientists believe that the realization of controlled nuclear fusion will take a hundred years, while others are optimistic that it will only take a few years. In fact, based on the current research progress, these are just unfounded speculations. We only hope to see this revolutionary technology come out in our lifetime.

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