Chapter 1 Current status of the nuclear power industry.
The total installed capacity of nuclear power that has been put into commercial use in China is 5699 gigawatts, the theoretical 55 nuclear power units that have been put into commercial use have an annual power generation of 455.9 billion kWh, which can meet the living electricity consumption of about 74.5 million people, because the Shidaowan Nuclear Power Plant was officially put into commercial use on December 6, 2023, and some other nuclear power plants were not fully charged, the actual total power generation last year was 4177800 million degrees.
1. There are 8 provinces with nuclear power plants in China: 5 nuclear power plants in Zhejiang, 4 nuclear power plants in Guangdong, 2 nuclear power plants in Fujian, 2 nuclear power plants in Shandong, 1 nuclear power plant in Guangxi, 1 nuclear power plant in Jiangsu, 1 nuclear power plant in Hainan, and 1 nuclear power plant in Liaoning.
2. The names of 17 nuclear power plants in China: Qinshan Nuclear Power Plant, Qinshan Second Nuclear Power Plant, Qinshan Third Nuclear Power Plant, Fangjiashan Nuclear Power Plant, Sanmen Nuclear Power Plant, Daya Bay Nuclear Power Plant, Lingao Nuclear Power Plant, Yangjiang Nuclear Power Plant, Taishan Nuclear Power Plant, Fangchenggang Nuclear Power Plant, Ningde Nuclear Power Plant, Fuqing Nuclear Power Plant, Tianwan Nuclear Power Plant, Changjiang Nuclear Power Plant, Hongyanhe Nuclear Power Plant, Haiyang Nuclear Power Plant, Shidaowan Nuclear Power Plant.
3. The current situation of China's inland nuclear power: After the Fukushima nuclear accident in Japan in 2011, the world has generally slowed down the speed of nuclear power construction projects. China has also suspended the construction of three major inland nuclear power projects, including the Taohuajiang Nuclear Power Plant in Hunan, the Dajia Nuclear Power Plant in Xianning in Hubei Province, and the Pengze Nuclear Power Plant in Jiangxi, and has carried out safety inspections of nuclear power projects under construction and in operation. Twelve years have passed, and inland nuclear power has not yet been activated.
Chapter II Classification of Main Equipment of Nuclear Power Plants.
The nuclear power plant is composed of nuclear island (NI), conventional island (CI) and auxiliary supporting facilities (BOP), and the main equipment of nuclear island, conventional island and auxiliary supporting facilities is introduced as follows:
1. Nuclear island equipment (primary circuit equipment): reactor pressure vessel, steam generator, voltage regulator, main pipeline, main pump, reactor internals, control rod driving mechanism.
2. Conventional island equipment (secondary circuit equipment): steam turbine, generator, deaerator, condenser, steam-water separation reheater, high and low pressure heater, main feed pump, condensate pump, main transformer, circulating water pump.
3. Auxiliary system (three-circuit equipment): equipment cooling water system, reactor chamber and waste fuel cooling system, auxiliary water supply system, ventilation and air conditioning system, compressed air system, radioactive waste treatment system.
Chapter 3 Principles of Nuclear Power Generation.
1. Nuclear power generation fuel.
Nuclear power generation uses the heat generated by the nuclear chain reaction of uranium fuel to heat water into high temperature and high pressure, and the heat released by the nuclear reaction is much higher than the energy released by burning fossil fuels (about a million times different), and the volume of fuel required is much less than that of thermal power plants. The purity of uranium-235 used in nuclear power generation is only about 3% to 4%, and the rest is uranium-238, which cannot produce nuclear **.
2. Nuclear power generation control (control rod of nuclear reactor).
The control rod is made of materials such as boron and cadmium that easily absorb neutrons. There is a set of mechanical devices outside the nuclear reaction pressure vessel that can manipulate the control rods. When fully inserted into the reaction center, the control rod is able to absorb a large number of neutrons to stop the fission chain reaction from proceeding. If the control rod is pulled out a little, the reactor will start to operate, and the speed of the chain reaction will reach a certain stable value; If you want to increase the amount of energy released by the reactor, you only need to pull out the control rod a little more, so that fewer neutrons are absorbed and more neutrons are involved in the fission reaction. To stop the chain reaction, the control rod is fully inserted into the nuclear reaction center to absorb most of the neutrons.
The start-up and shutdown of the nuclear reactor and the regulation of the nuclear power are all controlled by control rods. The material inside the control rod can strongly absorb neutrons, which can control the progress of the chain fission reaction in the reactor. The control rods are also assembled in the form of components. When the reactor is not operating, the control rods are inserted into the core. When the stack is opened, the control rod is lifted, and the height of the control rod is adjusted according to the needs during operation. In the event of an accident, all control rods will automatically fall rapidly, stopping the chain fission reaction in the reactor.
The start-up and stop of the nuclear reactor and the regulation of the nuclear power are mainly controlled by the control rods. The material inside the control rod can strongly absorb neutrons, which can control the progress of the chain fission reaction in the reactor. The control rods are also assembled in the form of components. When the reactor is not running, the control rod is inserted into the core, and the control rod is lifted when the reactor is opened, and the height of the control rod is adjusted as needed during operation. In the event of an accident, all control rods will automatically fall rapidly, stopping the chain fission reaction in the reactor.
Chapter 4 Introduction to Nuclear Island Equipment and Technology.
Nuclear power equipment is mainly divided into nuclear islands, conventional islands and auxiliary facilities, among which conventional islands and auxiliary facilities are basically similar to conventional thermal power generation equipment, so this chapter focuses on introducing the most critical nuclear island equipment technology.
1. Pressure vessel.
1. The reactor vessel (reactor pressure shell) refers to the closed container in which the nuclear reactor is placed and bears the huge operating pressure of the reactor. The inside of the vessel mainly contains a radioactive zone composed of nuclear fuel elements, etc., and a reactor coolant at high temperature and pressure. The pressure vessel is the main pressure boundary of the coolant and the second barrier against the escape of radioactive fission products. It is one of the key main equipment that cannot be replaced in nuclear power plants, and plays an extremely important role as a safety barrier. The quality standards of heavy-duty forgings are strict, and the fracture toughness of forgings in the core area needs to meet the strict requirements of 60-year design life of the core.
2. Main manufacturers of pressure vessels: China First Heavy Industries, Shanghai Electric, Dongfang Electric, Famatome (France), Doosan Heavy Industries (South Korea).
2. Steam generator.
1. The interior of the nuclear power plant usually contains a primary circuit system and a secondary circuit system, the nuclear fuel is fissioned in the reactor and produces a large amount of heat energy, and the high-temperature and high-pressure primary circuit cooling water brings the thermal energy out of the reactor, and transfers the heat to the water of the secondary circuit in the steam generator, so that they become steam to drive the steam turbine to drive the generator to generate electricity. The steam generator is connected to a pressure vessel in the primary circuit of the nuclear island, and heat is transferred to the secondary circuit through a U-shaped tube in it. Therefore, the radioactive primary liquid is isolated by the steam generator, so that the secondary circuit steam is non-radioactive and constitutes a protective barrier.
2. The U-shaped tube is the core component of the steam generator, with a very high technical threshold, both heat transfer and isolation, and extremely high technical requirements for it: 1) In order to improve the heat transfer efficiency in the structure, the outer diameter of the U-shaped tube is required to be narrow (1748mm), the pipe wall is thin (101mm）；2) High requirements for compressive, seismic and radiation resistance under harsh working conditions; 3) Stable work for 60 years.
3. Steam generator equipment manufacturer:
1) Steam generator: Shanghai Electric, Dongfang Electric.
2) U-tube (steam generator accessories): France Valinox, Japan Sumitomo, Sweden Sandrik, Baoyin Special Steel, Jiuli Special Materials.
Third, the main pipeline.
1. The main pipeline of the primary circuit of the nuclear island is a pipeline connecting the main equipment of the primary coolant system of the reactor, which is composed of a straight pipe section, an elbow and a pipe on the main pipeline. The pipeline between the reactor and the steam generator is called the hot section, the transition section between the steam generator and the main pump, and the cold section between the main pump and the reactor. The main pipeline is an important pressure boundary containing the reactor coolant, which belongs to the nuclear safety level 1 and seismic class I equipment.
2. Main pipeline manufacturers: Taiwan Strait Nuclear Power, Sanzhou Nuclear Energy, Bochuan Heavy Industry, Jilin Zhongyi, and Erzhong Heavy Equipment.
Fourth, the main pump. 1. The main pump is in the primary circuit system, and the main pump is used to drive the coolant to circulate in the reactor coolant system, and continuously transfer the heat generated in the reactor core to the secondary circuit feed water of the steam generator. The main pump is the key to controlling the water cycle in the operation of nuclear power, and it is also the only rotating equipment in the main equipment of the nuclear island, and it is the first-class equipment with the most difficult design and the longest cycle. Therefore, the main pump is like the "heart" of the nuclear island, which is crucial. At present, there are two mainstream technical routes: shaft seal pump and canned pump, and the difficulty is concentrated in the assessment of hydraulic design and long-term operation stability.
2. Main pump manufacturer:
1) Foreign manufacturers of main pumps: Westinghouse of the United States, EMD of the United States, Mitsubishi of Japan, Famatome of France, Thermon of France, KSB of Germany, Andritz of Austria, ASE of Russia, Sumy of Ukraine, and Flowserve of the United States.
2) Domestic manufacturers of main pumps: Harbin Electric Equipment, Dongfang Areva (a joint venture between Dongfang Electric and French Areva).
5. Valve. 1. The nuclear power valve is a large number of medium transportation control equipment used in the construction of nuclear power plants, which connects many systems of nuclear power plants and plays the roles of cut-off, regulation, diversion, anti-backflow, voltage stabilization and diversion. A nuclear power plant designed with two 1 million kW units requires 30,000 valves of various types, including globe valves, diaphragm valves, valves, check valves and butterfly valves. There are many important nuclear and non-nuclear valves in nuclear and conventional islands, such as pilot operated safety valves, main vapor isolation valves, regulating valves, etc.
2. Valve manufacturer:
1) Nuclear-grade valves (foreign manufacturers): France Wanato, the United States Tyco, Canada Veran.
2) Nuclear valves (domestic manufacturers): China Nuclear Su Valve, Shanghai Lianggong, Dalian Dagao, Shanghai Valve Factory, Yingliu shares.
3) Nuclear and grade valves: Jiangsu Shentong, Dalian Dagao, Neway shares.
6. Reactor internals.
1. The core equipment of the reactor undertakes important functions: accurately locates and supports the nuclear fuel assembly, and correctly guides the reactor control rod to start, stop and adjust the power of the nuclear reaction; Provide correct channels for reactor temperature measurement and neutron flux measurement, and establish a reasonable water flow channel for the reactor; It effectively shields the neutrons and rays bursting out of the core from the external material irradiation damage, which greatly prolongs the service life of the pressure vessel.
2. Manufacturer of reactor internals.
1) Foreign manufacturers of reactor internals: Famatus (France), Westinghouse (the United States), Doosan Heavy Industries (South Korea), AECL (Canada).
2) Domestic manufacturers of reactor internals: Shanghai Electric, Dongfang Electric.
7. Control rod drive mechanism.
1. The control rod drive mechanism directly affects the normal operation and safety performance of the reactor. The control rod driving mechanism is the key element of the core assembly, which is located in the top cover of the reactor pressure vessel, is connected with the control rod assembly, and realizes the insertion and lifting of the control rod assembly by energizing the three electromagnetic coils in a certain order, so as to control the average temperature of the reactor core, so as to achieve the purpose of safe start of the reactor, regulating the power of the reactor and stopping the reactor. High precision and strong stability. The control rod drive mechanism is responsible for the functions of reactor start-up, power regulation, power maintenance, normal shutdown and accident shutdown.
2. The main manufacturers of control rod drive mechanism: Shanghai Electric, Dongfang Electric, Zhefu Holdings.
Reference: China Nuclear Energy Industry Association: Refer to nuclear power installed capacity data.
National Nuclear Power: Control baton for nuclear reactors.
3. Wang Mi: Analysis of the development of the competitive pattern of localization of China's nuclear power subdivision equipment technology in 2019.