Nuclear fission opens the binding force of the nucleus.
Nuclear fusion, the fusion of atomic particles.
Nuclear decay, a naturally much slower form of fission.
Atoms consist of a positively charged nucleus and electrons with negative charges outside the nucleus. The thermal effect of ordinary chemical reactions comes from the change of bond energy when the outer electrons are rearranged, while the nucleus and inner electrons remain unchanged. In addition, the thermal effect of another reaction comes from the change of nucleus, which is called nuclear reaction. Nuclear reactions can be divided into three categories: nuclear decay, nuclear fission and nuclear fusion.
In order to safely apply the nuclear energy released by nuclear reaction to daily life and production in normal environment, the facilities that need to be taken are reactors composed of nuclear fuel and control rods, commonly known as atomic energy reactors.
198 1 year 1 month 65438+5, China's first atomic energy reactor was successfully rebuilt. Construction of the reactor began in May 1956, and it was put into operation two years later. Reactor is a device that keeps nuclear fission in a chain reaction, and it is the main form of utilizing the energy inside the nuclear at that time. The heat energy released by the reactor can be used to generate electricity, which can be used as a power device for ships, trains, airplanes and so on. Using reactors, isotopes can be made and scientific research can be carried out. The main purpose of China's first atomic energy reactor is to carry out scientific experiments and make isotopes. It uses uranium as fuel and heavy water as moderator and heat conductor, so it is called experimental heavy water reactor. Its completion marks that China has entered the era of atomic energy. The thermal power of this reactor is 7000 to 1000 kw. After the transformation, the reactor runs normally, the enhanced power is 50% higher than that before the transformation, the maximum thermal neutron flux is more than doubled, and the irradiation space of the reactor is also increased by 2.6 times, and low-concentration uranium is still used as fuel.
By around 2030, most of the nuclear power reactors in Japan, the United States and Europe will soon expire and will be retired one after another. Faced with this grim situation, Japan, Europe and the United States are currently stepping up research and development of a new generation of atomic energy reactors.
For example, the "supercritical water reactor" being developed by Tokyo University in Japan and Canada uses "supercritical water" as the coolant. This kind of water has both liquid and gas properties, and its heat transfer efficiency far exceeds that of ordinary "light water". Professor Kong Ph??ngMinh of the University of Tokyo said: The supercritical water reactor "is only half the size of the general reactor, and the construction cost can be saved by 30%-40%, and the power generation cost can be reduced by 30%". Their development goal is to reach the practical level in 2030.
Japan Atomic Energy Research Institute will devote itself to developing new breeder fast reactors. This new breeder fast reactor is called "Low Deceleration Spectrum Reactor" and its principle is the same as Manjusri breeder fast reactor. Manjusri fast reactor has not resumed operation since the accident of liquid sodium leakage occurred in 1995. In order to increase the safety of the reactor and control the cost of power generation, the coolant of the new breeder fast reactor is changed from liquid sodium to water. At present, Japan is developing this kind of water breeder fast reactor as a kind of reactor which is transitioning from ordinary reactor to liquid sodium breeder fast reactor. With this kind of reactor, thermal power generation can be obtained by hitting plutonium 238 in nuclear waste of nuclear power plant with neutrons, and plutonium 239 can also be produced as fuel.
France is studying and developing "ultra-high temperature gas reactor" and "gas high speed reactor". The ultra-high temperature gas reactor uses gas above 1000℃, and the gas high-speed reactor uses gas below 1000℃. In addition, France is still developing a "molten salt reactor", trying to use high-temperature molten salt containing lithium and uranium to generate electricity.
The liquid sodium cooled high-speed breeder fast reactor proposed by Britain and Japan is still very important, and the key is to increase the safety of liquid sodium in use. Russia has developed a "lead cooled reactor". Compared with liquid sodium, liquid lead is much safer.
Since 1999, the United States has implemented the "fourth generation plan", which has strengthened the research on nuclear waste recycling while developing new reactors. In July 2002, following the following three principles, the United States decided to develop six new types of reactors. The three principles are: 1, low power generation cost and construction cost; 2. Accidents are not easy to occur; It is difficult to transfer nuclear waste to weapons manufacturing. Six new reactor types, ultra-high temperature reactor, gas high-speed reactor, supercritical water reactor, lead-cooled reactor, sodium-cooled reactor and molten salt reactor reactor, were selected.