Analysis of the advantages and development prospects of nuclear power generation

Principles of nuclear power generation

There are four types of nuclear reactions: nuclear fission, nuclear fusion, particle bombardment, and nuclear decay. The nuclear fission chain reaction is the principle of nuclear power generation. The nuclei of larger atoms (such as uranium, thorium, plutonium) will split into multiple smaller nuclei after absorbing a neutron, while releasing two to three neutrons and huge energy, and the newly generated neutrons cause new nuclear fission, the fission reaction continues to continue, while constantly generating new energy, this process is the nuclear chain nuclear fission reaction. Nuclear fission chain reaction is the energy source of nuclear power generation.

The core device of nuclear power generation is the nuclear reactor, which is a device that can carry out a self-sustaining nuclear fission chain reaction in a controlled manner. It is mainly composed of core, reflector, control rod, reactor vessel and shielding layer. The nuclear fuel assemblies arranged in a certain way are concentrated in the core, and the self-sustaining nuclear chain reaction is carried out in this region. The core is also called the active zone. The core can convert nuclear energy into heat energy, creating conditions for nuclear energy utilization.

The structure of nuclear reactors is diverse, and it can be divided into different types of nuclear reactors according to the neutron energy distribution form, coolant type and other factors. According to the classification of neutron energy spectrum, it can be divided into thermal neutron reactor and fast neutron reactor. In fast neutron reactors, fission is caused by fast neutrons (with an average energy of about 0.1 MeV), so no neutron moderator material can be stored in the reactor. According to the classification of coolant, it can be divided into gas cooled reactor, liquid cooled reactor and liquid metal cooled reactor. Gas cooled reactors include carbon dioxide cooled and helium cooled reactors; Liquid cooled reactor mainly includes light water cooled pressurized water reactor and boiling water reactor, and heavy water cooled heavy water reactor. The reactors cooled by liquid metal are mainly those cooled by sodium and sodium-potassium alloys.

Since the advent of the first nuclear power plant in 1954, commercial nuclear power plants mainly have pressurized water reactors, boiling water reactors and heavy water reactors, the first two reactor coolant for light water (H2O), the latter coolant for heavy water (D20). Although the graphite water-cooled reactor and the graphite gas-cooled reactor have also been used for commercial power generation, their construction has been suspended for safety and economic reasons. Fast reactor and high-temperature gas cooled reactor nuclear power plants (plants) have not yet been commercialized and are under development and research. The power generation principle and system composition of all types of nuclear power plants are basically the same except reactor. At present, most nuclear power plants in the world use pressurized water reactor (PWR) for nuclear power generation. Modern PWR nuclear power plant is a new peak in the development of human energy utilization technology, and has played an important role in the world energy supply.

2. Advantages of nuclear power generation

First of all, compared with fossil fuel power generation, nuclear power generation will not emit a large amount of pollutants into the atmosphere, and nuclear power generation will not aggravate the global greenhouse effect;

Secondly, the shaft fuel used in nuclear power generation is only used for power generation. The world's nuclear resources are relatively rich, nuclear fuel uranium, lithium, boron, thorium deuterium and so on, uranium in the world's reserves of about 4.17 million tons. The energy that can be provided on the earth and the nuclear fuel resources that can be developed are more than 100,000 times that of fossil fuels. An economical and effective measure to alleviate the world energy crisis is the use of nuclear energy, which has many advantages, such as nuclear energy is millions of times larger than chemical energy, small size and high energy. The energy density of fossil fuels is millions of times lower than that of nuclear fuels, so the fuel used in nuclear power plants is small and easy to transport and store. And because the amount of nuclear fuel transported is small, nuclear power plants can be built near industrial areas where they are most needed. At the same time, a small amount of radioactive substances such as titanium, uranium, and radium in the coal will fall to the vicinity of the thermal power station with the smoke and dust, causing pollution to the environment. Nuclear power plants are built with layers of barriers, basically do not emit pollutants that pollute the environment, and radioactive pollution is much less than coal-fired power stations.

Finally, the proportion of fuel costs in the cost of nuclear power generation is relatively low, and the cost of nuclear power generation is not easily affected by the international economic situation, so the cost of power generation is more stable than other power generation methods.

Iii. Prospects for nuclear power generation

As a safe, reliable, clean and economical energy, nuclear energy has become the first choice of some developed countries and the trend of China's energy development. In recent years, according to the forecast of the economic construction and social development of countries around the world, the threat of global warming caused by the lack of energy resources and the greenhouse effect, coupled with the obvious advantages of nuclear power for environmental protection, will make the nuclear power industry flourish. As an advanced energy source, nuclear energy will play an important role in meeting future energy demand. In countries where the economy of the third world takes off, conventional energy production cannot meet the requirements of economic development, and it is necessary to supplement power generation capacity with nuclear power. Nuclear power plants built in the 1960s and 1970s in industrialized countries are coming to an end and new nuclear power is needed to replace them.

The sustainable development strategy and the goal of carbon neutrality and carbon peak have been accepted by many countries, organizations and most countries in the world, and actively take measures to prevent and control pollution and protect the ecological environment. Because nuclear energy has three advantages of economy, safety and no pollution, developing carbon-based alternative fuel of nuclear energy is one of the practical and effective measures and paths to implement sustainable development strategy, achieve the double carbon goal, prevent pollution and protect the ecological environment.

The future nuclear energy must be accepted by the public, and its public acceptance will become one of the important factors determining the scale of nuclear energy development. Nuclear energy has been from the climax of the 1960s and 1970s into a low tide, in addition to the world economy from the rapid development stage to the stage of stable development, energy and power demand growth declined significantly, nuclear energy development process also occurred Three Mile Island and Chernobyl two major nuclear accidents, caused public panic. Public acceptance and safety concerns have become a major obstacle to the development of nuclear energy, but also an important reason.

Judging from the general trend of nuclear power development, the technical and strategic routes of China's nuclear power development have long been clear and are being implemented. By the first quarter of 2022, China has built 54 nuclear power units in operation, with an installed nuclear power capacity of 54.43 million kilowatts, all of which are distributed in coastal areas, and coastal areas will remain key areas for nuclear power construction in the future. The third generation nuclear power technology has been more mature, with higher safety and economy, it is expected that in the next period of time, the new construction of nuclear power technology is still dominated by the third generation nuclear power technology. China's nuclear power generation is increasing year by year, and its proportion in the power structure is also expanding. As of January to May 2022, China's nuclear power generation is 166.3 billion KWH, an increase of 4.5% over the same period in 2021, and the proportion is increased to 5.1%. Overall, the current proportion is still small, but there is a large room for subsequent permeability improvement. With the support of national policies and the promotion of electricity marketization, the future of nuclear energy development is promising!