The release, control and utilization of atomic energy is one of the major scientific and technological achievements in the 20th century. Atomic energy is the energy released by the chain reaction of nuclear fission, so it is also called nuclear energy. Nuclear fission and chain reaction are carried out in atomic reactors, so atomic reactors are the "boilers" of nuclear power plants.
At present, most nuclear power plants use light water reactors. Light water reactor uses uranium -235 as fuel and water as moderator to slow down high-speed neutrons and as coolant. A light water reactor with a power generation capacity of 6.5438+0 million kilowatts uses about 3 kilograms of uranium -235 every day. Although the amount used is very small, due to the limited natural uranium reserves, it has been proved that it can be used for about 1000 years, of which uranium -235 only accounts for about 0.7% and 99.3% is uranium -238. Both uranium -235 and uranium -238 are isotopes of uranium, and their nuclei will split. However, uranium -235 has its own unique fission mode. When the neutron hits its nucleus, the nucleus will split into two parts with almost equal weight, and uranium -238 does not have the above fission mode, so it cannot be used as fuel for light water reactors. Therefore, in today's nuclear fuel of nuclear power plants, uranium -235 is like "high quality coal", while uranium -238 is like "coal gangue", which can only be piled there as nuclear waste and become a "public hazard" that pollutes the environment.
In order to solve the above problems and make full use of uranium resources, scientists are developing and designing another type of reactor-fast neutron reactor, referred to as "fast reactor". The fast reactor uses plutonium -239 as fuel instead of uranium -235, but uranium -238 is placed in the peripheral regeneration area of the core fuel plutonium -239. The fast neutrons released by the fission reaction of plutonium -239 are absorbed by uranium -238 in the peripheral regeneration zone, and uranium -238 will soon become plutonium -239. In this way, plutonium -239 fission, while generating energy, continuously converts uranium -238 into usable fuel plutonium -239, and the regeneration rate is higher than the consumption rate, and the nuclear fuel is burned more and more, which rapidly proliferates, so this kind of reactor is also called "fast neutron breeder reactor". According to calculation, if the fast neutron reactor is popularized and applied, the utilization rate of uranium resources will be increased by 50-60 times, and the problems of massive accumulation and waste of uranium -238 and environmental pollution will be solved.
Technically, fast reactor is much more difficult than light water reactor. However, due to its unique advantages, the United States, France, Japan, Germany, Russia and other countries are actively developing fast neutron reactors. As early as 1967, France built an experimental reactor. 1974, 250,000 kw fast neutron reactor was put into operation. 19841.2000 kw large commercial fast reactor nuclear power plant. Japan has also designed a fast neutron reactor with an output power of 300,000 kilowatts. The mixed oxide of uranium and plutonium is used as nuclear fuel in the core, and uranium 238 is around the core. This fast reactor can increase the utilization rate of uranium resources by 50 times, and the economic and social benefits are very obvious. In addition to the above five countries, Australia, Norway, Spain, Sweden, Switzerland, Italy and China are also actively carrying out related research work.
Since the 1970s, atomic energy has been used in the cause of peace, and has achieved rapid development. Nuclear power plants have mushroomed, gradually replacing fossil fuel power plants and becoming the protagonist of the energy stage. According to statistics, there are more than 400 nuclear power plants in the world, and the power generation accounts for about 17% of the world's total power generation. Among them, France, the country with the fastest development of nuclear power, has accounted for 40% of nuclear power. Nuclear power has the advantages of large energy, small area, safety, reliability, no terrain restrictions, convenient fuel transportation and so on, and has broad development prospects. After the completion of Qinshan and Daya Bay nuclear power plants in China, the 10 nuclear power plant will be built. Fast neutron reactor is called "nuclear fuel production plant", which is a wonderful flower in nuclear power and an important role in the future energy stage.