Once the controllable nuclear fusion is realized, will the tritium on the earth be used up? Only a few kilograms

Controllable nuclear fusion technology is extremely important for human beings, because the realization of controllable nuclear fusion can not only provide humans with a powerful way to obtain energy, but more importantly, it can fundamentally solve the problem between development and the environment. the contradiction.

Controllable nuclear fusion is different from the controllable nuclear fission technology used in today's nuclear power plants. Because it can react stably in the natural environment, there is no risk of nuclear leakage. It can be described as an absolute clean energy. Replacing fossil fuels with controllable nuclear fusion can fundamentally cut off the emission of atmospheric pollutants, thus solving a series of atmospheric environmental problems represented by the greenhouse effect. Moreover, fossil fuels are non-renewable energy sources, and it is only a matter of time before they are exhausted in view of the increasing energy demand of mankind. Therefore, whether from the perspective of environmental protection or from the development needs of human civilization, controllable nuclear fusion is of great significance, so it is also regarded as a symbol of the realization of the first universe civilization.

Although controllable nuclear fusion is good, it is also very difficult to achieve. For example, how can we use magnetic fields or inertia to stably constrain the tritium and deuterium participating in the reaction, so as to avoid these high-temperature plasmas from coming into substantial contact with any substance; and How can the balance of energy output be achieved; where does the fuel involved in the reaction come from?

There are still many such problems, so it is generally believed that the realization of controllable nuclear fusion may be a hundred years away, and there are relatively optimistic views that China's artificial sun is expected to be realized in 2040. It's really a good thing. The realization of controllable nuclear fusion is difficult, and once it is realized, there is a new problem in front of us, that is, once the controllable nuclear fusion is realized, will it be able to find enough fuel support on the earth? In fact, there are many fuels that can be used in controllable nuclear fusion, including deuterium-deuterium fusion, deuterium-tritium fusion, deuterium-helium fusion, and helium-helium fusion, etc. Different reaction methods have different difficulties.

Taking helium-helium fusion as an example, the required temperature is currently difficult to achieve, so compared with other reaction methods, deuterium-tritium fusion is the easiest to achieve, which is also the current research direction of controllable nuclear fusion in all countries.

So, is there enough deuterium and tritium on Earth? The reserves of deuterium on the earth are very rich. There is a large amount of deuterium in the earth's oceans. According to previous research data, the deuterium content in the earth's oceans is about 45 trillion tons, so we don't need to worry about not having enough deuterium. of deuterium to participate in controlled nuclear fusion. So if there is deuterium in the ocean, is there also tritium? There are, but the reserves are very limited, at least until Japan dumps nuclear waste into the ocean. Having said that, you finally understand why the word "tritium" is so familiar. Yes, the main radioactive pollutant in the nuclear waste water discharged by Japan into the ocean is tritium. However, according to the data provided by Japan, the total content of tritium in the nuclear waste water it discharges is only less than 3 grams. If this is the case, then it can be said that the harm is not too big, but as to whether it is really only such a small amount of tritium, we do not know. , also declined to comment.

The reserves of tritium are limited, so how limited is it? We must first understand what tritium is and how does it come from?

Tritium is one of the isotopes of hydrogen, but it is a very unstable isotope. Compared with those radioactive elements whose half-life is tens of millions of years, the half-life of tritium is only 12.43 years. To put it simply, every 12.43 years, Half of the tritium decays into helium-3. The half-life is so short, which determines that tritium cannot be accumulated through time. No matter how it is produced, it is difficult to accumulate more and more in the long river of time.

So how is tritium produced? As far as tritium on the earth is concerned, its main production method is the impact of cosmic rays on the deuteron nucleus and the fission reaction in the nuclear power plant. Since the output is extremely limited and the half-life is very short, the content of tritium on the earth is also very rare. .

On the surface of the earth, tritium can be said to be scattered in every corner, and if all the tritium scattered on the surface of the earth is collected, it may only look like five or six pounds, so there is no need to worry that controlled nuclear fusion will consume all the tritium, Because it was close to nothing.

Since the tritium on the earth's surface is so barren, how can it support controlled nuclear fusion? Although the amount of tritium on the Earth's surface is extremely limited, we can make it artificially, and we can make it in the process of nuclear fusion. In the process of deuterium-tritium fusion, neutrons are generated. If the generated neutrons can be controlled and used to bombard lithium-6, then tritium can be obtained, but the direction of movement of the neutrons generated by the reaction must be controlled. It is still difficult to do it now. If a control method can be found in the future, then the research and development of controllable nuclear fusion will take a big step forward. Moreover, the reserves of lithium-6 are still very rich on the earth, and within a thousand years No need to worry about running out.