Chasing the dream of the "artificial sun"

——Globally promote the commercialization of nuclear fusion power generation

　　Technological innovation world wave

　　◎Reporter Liu Xia

　　According to a recent report by the American Fun Science website, American scientists have produced a large amount of energy through nuclear fusion, which is one step closer to the ideal goal of "fusion ignition".

Fusion ignition means that more energy is created than consumed, which brings hope to the development of nuclear fusion, a new clean energy source.

　　China, the United States, Japan, India and other countries are working together to carry out the "International Thermonuclear Fusion Experimental Reactor" (ITER) project in southern France, which is scheduled to start operation in 2025.

In addition to the government's heavy investment, there are also many large technology companies around the world that are committed to promoting the commercial use of nuclear fusion power generation.

But in order to achieve this goal, there are still many problems to be solved.

"Artificial sun" attracts attention

　　Nuclear fusion is different from the fission technology currently used in nuclear power plants.

During the fission process, the bonds of the heavy atom nuclei will be broken and energy will be released, but if this process cannot be controlled, it will cause a serious nuclear accident.

　　According to a report on the website of Nihon Keizai Shimbun on August 20, during the fusion process, two light nuclei will "combine" together to create a heavy nucleus.

Nuclear fusion requires the use of deuterium (heavy hydrogen) and tritium (superheavy hydrogen) with neutrons in the nucleus. When high temperatures are reached, the atoms decompose into positively charged nuclei and negative electrons, forming a high-speed flowing "plasma" state.

When sealed under a magnetic field, these substances will collide and fuse violently, and the huge energy generated can be effectively used as heat energy for power generation.

In theory, 1 gram of fuel produces energy equivalent to 8 tons of oil.

　　In the interior of stars, including the sun, the same process is carried out, so the recurrence of nuclear fusion reactions on the ground is also called "the sun on the ground."

　　Nuclear fusion has several advantages.

First of all, nuclear fusion will stop the reaction when the fuel is insufficient or the plasma is unstable, so it is easier to control than nuclear fission; second, although nuclear fusion will also produce radioactive waste, it produces very little waste and does not emit it. Greenhouse gases; again, the direct fuels (deuterium and tritium) required for nuclear fusion are very easy to obtain-both can be obtained by electrolysis of water, which has significant cost advantages.

In view of this, some scientists believe that nuclear fusion is a potential future energy source.

Technology companies compete

　　Nuclear fusion has so many advantages that it has attracted governments and technology companies to invest in research.

　　For example, China, the United States, Japan, India and other countries are carrying out the ITER project in Cadarache, southern France. The goal is to start operation in 2025, and the total construction cost will reach about 25 billion US dollars.

　　According to Bloomberg News on July 17, the US federal government passed a bill last December to allocate US$4.7 billion for nuclear fusion and related research, including a payment of US$1.5 billion to ITER.

The National Academy of Sciences issued a report in February this year, suggesting that "the Department of Energy and the private sector should build a nuclear fusion test plant in the United States between 2035 and 2040."

　　Technology companies are also competing to make efforts.

The start-ups aided by US Microsoft founder Bill Gates and the research on nuclear fusion power generation that Google in the US are involved in are aiming to commercialize it as a decarbonized power source.

The Massachusetts Institute of Technology (MIT) is working on a project with its subsidiary Federal Fusion Systems. The goal is to trial-produce a nuclear fusion reactor in 2025. The ultimate goal is to develop a 200-megawatt power station.

　　According to data from the consulting agency Crunchbase, at present, individuals and organizations such as Jeff Bezos and Cenovus Energy have invested approximately US$127 million in General Fusion, which is expected to build a building in the UK by 2025. The commercial factory is expected to be completed within ten years.

　　At the same time, many other nuclear fusion startups similar to General Fusion have also received billions of dollars in funding from the government and large companies. Take the California-based TAE Technology Company as an example. It has raised 8.8 in the past 23 years. One hundred million U.S. dollars.

　　The National Quantum Science and Technology Research and Development Institute in Ibaraki Prefecture, Japan, has completed the main construction of its experimental research reactor "JT-60SA". It will be completed in 2021 and start experiments. It is expected to reproduce the nuclear fusion reactor in recent tests. The desired plasma state.

It is reported that the Ministry of Education, Culture, Sports, Science and Technology of Japan allocates approximately US$200 million to ITER and "JT-60SA" each year.

　　In addition, the University of Tokyo will also conduct joint research with the British start-up Tokamak Energy, and will commit to implementing experiments to increase the plasma temperature to 100 million degrees Celsius during the year.

Professor Yasushi Ono of the University of Tokyo said: "The advantage of start-ups is a quick fight. At present, the entire project is progressing in an orderly manner."

Many problems have yet to be resolved

　　Nuclear fusion power generation looks promising, but the cost and time required to reach a practical level are unpredictable.

　　For example, in Japan, which private company will be responsible for commercialization has not yet been determined.

Previously, the fast baryon breeder reactor "Monju" was once regarded as Japan's hope of achieving resource self-sufficiency and was highly anticipated. The investment exceeded 1 trillion yen, but the commercialization failed in the end.

"Nihon Keizai Shimbun" reported that if the nuclear fusion power generation project is not clear about the responsibilities of the government and the enterprise, it is likely to repeat the same mistakes.

　　In addition, although the radiation level is not high, nuclear fusion power generation still generates radioactive waste.

In Japan, after the Fukushima nuclear power plant accident, public opinion on the prudent use of nuclear power for power generation has increased.

To achieve commercialization, in addition to considering cost and technology development, it also needs to be understood by the public.

　　More importantly, nuclear fusion is quite difficult to implement.

This process will produce incredibly high temperatures and require a large amount of energy input-energy input has so far exceeded the output, which is one of the biggest obstacles preventing nuclear fusion from becoming a viable energy source.

　　The American Interest Science website pointed out in a report that scientists at the National Ignition Experimental Facility (NIF) concentrated a giant laser array containing 200 lasers on a tiny spot, creating a huge burst of energy, which was the result of the energy they created in the past. 8 times.

Although this energy lasted only one-tenth of a billionth of a second, it brought scientists one step closer to "fusion ignition".

　　And Jeremy Chittenden, a person in charge of NIF, said cautiously: "It may be a long process to transform this concept into a renewable power source, and many major technical difficulties need to be overcome."