Nuclear fission, which opens the bonds of atomic nuclei.
Nuclear fusion, in which the particles of an atom fuse together.
Nuclear decay, the natural and much slower form of fission.
An atom consists of a positively charged nucleus and negatively charged electrons outside the nucleus. The thermal effect of an ordinary chemical reaction arises from the change in bonding energy when the outer electrons are rearranged, while the nucleus and the inner electrons do not change. In addition, there is another type of reaction of the thermal effect from the atomic nucleus of the change, this type of reaction is called a nuclear reaction. Nuclear reactions can be divided into three categories: nuclear decay, nuclear fission and nuclear fusion.
In order to be able to safely apply the nuclear energy released from nuclear reactions to daily life and production in a normal environment, it is necessary to take the facilities, i.e., nuclear fuel and control rods composed of reactors, commonly known as atomic energy reactors.
On January 15, 1981, China's first atomic energy reactor was successfully rebuilt. The construction of this reactor was started in May 1956 and it was officially operational two years later. A reactor is a device that makes atomic nuclei split to maintain a chain reaction, which was the main form of utilizing the energy inside atomic nuclei at that time. The heat energy released from the reactor can be used to generate electricity and as a power plant for ships, trains, airplanes, etc. Reactors can be utilized to create isotopes and conduct scientific research. The main use of China's first atomic energy reactor was to conduct scientific experiments and make isotopes. It used uranium as fuel and heavy water as a moderator and heat conductor, so it was called an experimental heavy water type reactor. Its construction marked the beginning of China's transition into the atomic energy era. The thermal power of this reactor was 7,000 to 10,000 kilowatts. The reactor was modified to operate normally, with a 50% increase in reinforcement power over the pre-modification level, a more than doubling of the maximum thermal neutron flux, and a 2.6-fold increase in the irradiated space of the reactor, which was still fueled by low-enriched uranium.
By 2030 or so, Japan, the United States and Europe are now operating most of the nuclear power plant atomic power reactors will expire and will be decommissioned one after another. In the face of this grim situation, Japan, Europe and the United States are now stepping up research and development of a new generation of nuclear power reactors.
For example, the University of Tokyo in Japan and Canada *** with the research and development of the "supercritical water reactor", its coolant using "supercritical water". This water has both liquid and gas properties, heat transfer efficiency is far superior to ordinary "light water". Prof. Yoshiaki Okazaki of the University of Tokyo said that the supercritical water reactor "is only half the size of a normal reactor, and the construction cost can be saved by 30-40%, and the cost of generating electricity can be reduced by 30%". The goal of their development is to reach a practical level by 2030.
The Japan Atomic Energy Research Institute (JAERI), on the other hand, is focusing its development on a new type of breeder fast reactor. This new breeder reactor is called the "low deceleration spectrum reactor", and its principle is the same as the "Bunshu" breeder reactor. "The Bunshu fast reactor has not resumed operation since the liquid sodium leakage accident in 1995. In order to increase reactor safety and control power generation costs, the coolant of the new breeder fast reactors is water instead of liquid sodium. Currently, Japan is developing this water-breeder fast reactor as a type of reactor for the transition from ordinary reactors to liquid sodium-breeder fast reactors. With this reactor, the neutron impact of nuclear power plant nuclear waste plutonium-238 can be thermoelectric power generation, but also can produce plutonium-239 can be used as fuel.
France is researching the development of "ultra-high-temperature gas reactors" and "high-speed gas reactors. "
Britain and Japan proposed liquid sodium cooling high-speed breeder fast reactor is still very important, the key is to increase the safety of the use of liquid sodium. Russian research and development is "lead-cooled reactor", compared with liquid sodium, liquid lead safety is much higher.
Since 1999, the United States began to implement the "Generation IV Program", in the development of new reactors at the same time, to strengthen the recycling of nuclear waste research. 2002 July, the United States in the following three principles of the premise of the decision of the six new types of reactors research and development guidelines. The three principles are: 1) low cost of power generation and construction; 2) less susceptible to accidents; and 3) difficult to divert nuclear waste to weapons manufacturing. The six new types of reactors selected are: ultra-high temperature reactors, gas-fired high-speed reactors, supercritical water reactors, lead-cooled reactors, sodium-cooled reactors, and molten salt reactors.