As we all know, thermal power stations use coal and oil resources to generate electricity, hydropower stations use Hydropower to generate electricity, and wind power generation uses wind energy to generate electricity. What does nuclear power stations use to generate electricity? How does it work? What are the advantages and disadvantages?
1. Composition and principle of nuclear power plant
Nuclear power station is a new type of power station that uses the energy contained in the atomic nucleus to generate electric energy after conversion. It usually consists of two parts: Nuclear Island (N1) and conventional island (CI).The main equipment in the nuclear island is nuclear reactor and steam generator, while the main equipment in the conventional island is gas turbine and generator and their corresponding auxiliary equipment.
The nuclear power plant uses uranium, a very heavy metal, as raw material. Uranium is used to make nuclear fuel and put it into the reactor. Fission occurs in the reactor equipment to produce a large amount of heat energy. The water under high pressure brings out the heat energy and generates steam in the steam generator to convert the heat energy into mechanical energy. The steam drives the gas turbine to rotate at high speed with the generator,convert mechanical energy into electrical energy, and electrical energy will be continuously produced. This is the working principle of nuclear power plant.
2. Advantages and disadvantages of nuclear power
Compared with thermal power plants, nuclear power plants have the advantages of small waste volume, high production capacity and low emission.The main raw material for thermal power plants is coal. According to relevant data, the energy released by the complete fission of 1 kg of uranium-235 is equivalent to the energy released by the combustion of 2700 tons of standard coal, it can be seen that the waste of nuclear power plant is far less than that of thermal power plant, while the unit energy produced is far higher than that of thermal power plant. At the same time, there are natural radioactive substances in coal, which will produce a large number of toxic and slightly radioactive ash powder after combustion. They are also directly released into the environment in the form of fly ash, causing serious air pollution. However, nuclear power plants use shielding means to prevent pollutants from being discharged into the environment and protect the environment from radioactive substances to a certain extent.
However, nuclear power plants also face two difficult problems. One is thermal pollution. Nuclear power plants will emit more waste heat into the surrounding environment than ordinary thermal power plants, so the thermal pollution of nuclear power plants is more serious.The second is nuclear waste. At present, there is no safe and permanent treatment method for nuclear waste. Generally, it is solidified and stored in the waste warehouse of nuclear power plant, and then transported to the place designated by the state for storage or treatment after 5-10 years.Although nuclear waste cannot be eliminated in a short time, the safety of their storage process is guaranteed.
There is also a problem that makes people get scared when talking about nuclear power - nuclear accidents. There have been several major nuclear accidents in history, resulting in the leakage of radioactive substances from nuclear power plants into the air, causing permanent damage to people and the environment, and the development of nuclear power has stalled. However, with the deterioration of the atmospheric environment and the gradual depletion of energy, nuclear power, as the only clean energy that can replace fossil fuels on a large scale, has returned to the public view.Countries have begun to restart nuclear power plants. On the one hand, they strengthen the control of nuclear power plants, re plan and increase investment. On the other hand, they improve equipment and technology and seek a safer operation mode of nuclear power plants. After years of development, the safety and reliability of nuclear power have been further improved. The energy transmitted by nuclear power to various places through the power grid is also gradually increasing, and slowly began to enter people's daily life.
3. Nuclear power valves
Nuclear power valves refer to the valves used in nuclear island (N1), conventional island (CI) and power station auxiliary facilities (BOP) systems in nuclear power plants.In terms of safety level, it is divided into nuclear safety level I, II, III and non nuclear level.Among them, nuclear safety level I requirements are the highest.Nuclear power valve is a large number of medium transmission control equipment used in nuclear power plant, and it is an essential and important part of the safe operation of nuclear power plant.
In the nuclear power industry, nuclear power valves, as an indispensable part, should be selected with caution. The following aspects should be considered:
(1) The structure, connection size, pressure and temperature, design, manufacturing and experimental test shall comply with the design specifications and standards of the nuclear power industry;
(2) The working pressure shall meet the pressure level requirements of various levels of the nuclear power plant;
(3) The product shall have excellent sealing, wear resistance, corrosion resistance, scratch resistance and long service life.
Hikelok has been committed to providing high-quality instrument valves and fittings to the nuclear power industry for many years. We have successively participated in the supply projects of Daya Bay nuclear power plant, Guangxi Fangchenggang nuclear power plant, 404 plant of China National Nuclear Industry Corporation and Nuclear Power Research Institute. We have strict material selection and testing, high standard processing technology, strict production process control, professional production and inspection personnel, and strict control of all links. The products have contributed to the nuclear power industry with excellent performance and stable structure.
4. Purchase of nuclear power products
Hikelok products are designed and produced in strict accordance with the standards of the nuclear power industry, and meet the requirements of instrument valves, fittings and other products required by the nuclear power industry in all aspects.
Twin ferrule tube fitting: it has passed 12 experimental tests including vibration test and pneumatic proof test, and is treated with advanced low-temperature carburizing technology, which provides a reliable guarantee for the actual application of ferrule; The ferrule nut is processed by silver plating, which avoids the biting phenomenon during installation; The thread adopts rolling process to improve the hardness and finish of the surface and prolong the service life of the fittings. The components are equipped with reliable sealing, anti leakage, wear resistance, convenient installation, and can be disassembled and disassembled repeatedly.
Instrumentation weld fitting: the maximum pressure can be 12600psi, the high temperature resistance can reach 538 ℃, and the stainless steel material has strong corrosion resistance.The outer diameter of the welding end of the weld fittings is consistent with the size of the tubing, and can be combined with the tubing for welding.The welding connection can be divided into metric system and fractional system. The fittings forms include union, elbow, tee and cross, which can adapt to a variety of installation structures.
Tubing: after mechanical polishing, pickling and other processes, the outer surface of the tubing is bright and the inner surface is clean.The working pressure can reach 12000psi, the hardness does not exceed 90HRB, the connection with the ferrule is smooth, and the sealing is reliable, which can effectively prevent leakage during the pressure bearing process. Various sizes of metric and fractional systems are available, and the length can be customized.
Needle valve: the material of instrument needle valve body is ASTM A182 standard. The forging process has a compact crystal structure and strong scratch resistance, which can provide a more reliable repetitive seal. The conical valve core can continuously and slightly adjust the medium flow. The valve head and valve seat are extruded seal to improve the service life of the valve.The compact design meets the installation requirements in a narrow space, with convenient disassembly and maintenance and long service life.
Ball valve: the valve body has one-piece, two-piece, integral and other structures. The top is designed with multiple pairs of butterfly springs, which can resist strong vibration. Provide metal sealing valve seat, small opening and closing torque, special packing design, leak proof, strong corrosion resistance, long service life, and a variety of flow patterns can be selected.
Proportional relief valve: as the name suggests, the proportional relief valve is a mechanical protection device, which can set the opening pressure. It works under high pressure and is less affected by back pressure. When the system pressure rises, the valve opens gradually to release the system pressure. When the system pressure drops below the set pressure, the valve reseals quickly, safely ensuring the stability of the system pressure, small volume and convenient maintenance.
Bellows-sealed valve: the bellows-sealed valve adopts precision formed metal bellows with strong corrosion resistance and more reliable guarantee for on-site work. The valve head adopts non rotating design, and the extrusion seal can better prolong the service life of the valve. Each valve passes the helium test, with reliable sealing, leakage prevention and convenient installation.
Hikelok has a wide range of products and complete types. It can also be customized according to customer needs. Later, engineers will guide the installation in the whole process, and the after-sales service will respond in time. More products applied to the nuclear power industry are welcome to consult!
For more ordering details, please refer to the selection catalogs on Hikelok's official website. If you have any selection questions, please contact Hikelok's 24-hour online professional sales personnel.
Post time: Mar-25-2022