Analysis on Control Points of Nuclear Power Plant Valve Supervision Process
Abstract: Nuclear power plant valves are the key devices in nuclear power plants, mainly used for various control tasks in the operation of nuclear power plants. In general, valves are an important auxiliary facility, which is widely used in nuclear islands and conventional islands. The performance of the valve during the normal operation of the nuclear power plant is directly related to the safety of the nuclear power plant equipment. Therefore, strengthening the control of the nuclear power plant valve manufacturing process is conducive to the safe operation of the nuclear power plant.
Key words: nuclear power plant; valve manufacturing; quality control introduction At present, there are many nuclear power plant valve manufacturers in China, but some manufacturers' valve quality control system is not perfect, and related enterprises lack nuclear safety awareness in the production process, and then make the production The valve cannot meet the needs of the nuclear power plant. In order to improve the manufacturing level and quality of nuclear power plant valves, relevant staff should strengthen the supervision of the valve manufacturing process, timely eliminate the defects and quality problems of valve products, and thus ensure the safety of nuclear power plants, and ultimately promote the development of China's nuclear power industry.
1 Introduction to Nuclear Power Plant Valves 1.1 Basic Characteristics of Nuclear Power Plant Valves Nuclear power plant valves are mainly installed on the pipelines of nuclear power equipment to control the flow of fluids in related equipment. Nuclear power plant valves have many functions, including interception, diversion, diversion, backflow prevention, pressure regulation, overflow relief, and regulation of flow. Nuclear power plant valves are an indispensable device in the daily operation of nuclear power plants and a reliable guarantee for the safe operation of nuclear power plants.
1.2 The basic structure of the valve The common nuclear power plant valves mainly have the following forms: gate valve, globe valve, ball valve, butterfly valve, diaphragm valve, check valve, regulating valve, safety valve and so on. These valves can play different roles depending on the installation method. The working environment of nuclear power plant valves is rather harsh. The types and temperatures of the valves passing through the valves are different. The nuclear power plants are radioactive, and the nuclear island valves should also have radiation resistance requirements.
1.3 Characteristics of Nuclear Power Plant Valves In the manufacture of nuclear power plant valves, relevant enterprises must first clarify the actual use of valves, because nuclear power plant valves are very different from those used in other occasions. Nuclear power plants have higher standards and requirements for valve quality. Therefore, relevant companies in the process of manufacturing valves, should try to configure ASME, RCC-M type of standard valves to ensure the safety index of the valve. The American Society of Mechanical Engineers (ASME) has set stricter standards for the manufacture of valves for nuclear power plant equipment and has assigned a corresponding level of safety. Among them, the number of diaphragm valves should account for 26.2% of the total number of nuclear power plant valves, the shut-off valve accounts for 33.6%, and the nuclear island valve accounts for 12.8%. At the same time, the number of valves meeting the safety index should not be less than 2.3%, and the total number of second- and third-stage valves should be It accounts for 52% of the total number of valves.
In addition to the intricate environment of the working conditions of the nuclear power plant valves, the radioactivity, temperature and pressure levels of the transport medium are also very demanding. The medium transported by the nuclear power plant valves is mainly saturated steam, condensed water, water vapor, primary circuit coolant, radiation corrosives, dilute sulfuric acid, lye and other media. There are four kinds of working conditions: normal, abnormal, emergency and accident. Common faults include internal leakage, external leakage and inoperability. If there is a problem with the quality of the nuclear power plant valve, failure to perform its safety function or directly cause a nuclear leak will seriously affect the safety of the nuclear power plant equipment, threatening the environment and people's health.
1.4 Localization of Nuclear Power Plant Valves In the past, China's nuclear power plants mainly used valves produced abroad, mainly because the design, test, manufacturing and quality inspection systems of imported nuclear power valves were relatively perfect, and the experience and technology of foreign manufacturers were relatively mature. In recent years, with the advancement of China's science and technology, domestically produced nuclear power valves have made great progress, but there are still insufficient design and research capabilities and insufficient testing capabilities, forging (die forging) and special high-end welding technology is not mature, manufacturing quality is not The status quo of stability and management system is not perfect. Therefore, the relevant state departments have put forward higher requirements for the quality control of the domestic nuclear power valve supervision process.
2 Nuclear power valve manufacturing control points analysis 2.1 Improve the technical standards and specifications of domestic nuclear power valves In order to further improve the quality and level of domestic nuclear power valve design, material selection, inspection and other aspects, the relevant national departments should quickly put the existing EJ, GB The relevant content of nuclear power valve manufacturing in technical standards and specifications is supplemented and improved according to the internationally advanced ASME and RCC-M standards, and the final standard is guaranteed to conform to China's actual national conditions and improve the operability of the valve manufacturing process. In this way, it is conducive to the domesticization of domestic nuclear power valves in all aspects of design, material selection and inspection.
2.2 Accelerate the realization of domestic nuclear power valve quality testing resource sharing By integrating the sharing of domestic nuclear power valve industry design, experiment, testing equipment and other resources, we can effectively avoid the repeated investment research of related enterprises, and accelerate the research process of China's nuclear power valve localization. In addition, domestic nuclear power valve laboratories and nuclear power valve testing and identification equipment should be managed by the state. All domestic nuclear power valve manufacturers can use these resources together, thus avoiding repeated investment in the same project, which not only saves the enterprise. Production costs can save the country a lot of manpower, material resources and financial resources.
2.3 Strengthening the quality control in the manufacturing process of nuclear power valves Nuclear power plants have very high requirements on the distribution and composition of chemical substances in valve forgings and castings. At the same time, there should be no obvious defects such as pores and slag inclusions on the surface of the valve body. In the quality control process of nuclear power valves, the staff should attach great importance to the wall thickness of forgings and castings, and do not allow negative deviations. At the same time, valve manufacturers should be required to provide complete non-destructive testing report or other quality of valve parts. certified documents. Valve supervisors also need to carefully check the quality of the valve raw materials, review the raw material quality certificate, and review the material grades and specifications used for the valve to ensure that the raw materials used meet the actual application requirements of the valve. When the valve supervisory personnel conduct supervision and management at the production site, it is necessary to check the appearance quality of the valve components. If the appearance quality is unqualified, it is necessary to carry out rectification in time.
The inspection management personnel must strictly review the non-destructive testing report to ensure that all non-destructive testing sites, testing methods, sampling rates, acceptance criteria, testing levels, testing personnel qualifications, and testing reports are in compliance with relevant technical agreements and design standards. Requirements; valves must undergo strict leak testing to ensure strength and tightness of the valve body. Due to the many influencing factors in the valve manufacturing process, it is inevitable that there will be cases that do not meet the requirements, standards or documentation requirements. When the nuclear power plant owner or the contractor carries out the valve acceptance inspection at the valve manufacturer, the non-conformance processing documents and non-conformities and deviation treatment reports shall be checked to ensure that the problem of the unqualified valves is finally resolved in the manufacturer.
2.4 Strengthening personnel training and technology introduction In order to effectively improve the design level and manufacturing quality of domestic nuclear power valves, relevant enterprises should strengthen the cultivation of professional talents and the introduction of advanced technologies. Domestic nuclear power valve manufacturers should pay attention to the manufacturing quality of nuclear power valves, increase investment in software and hardware in the production process, ensure the advanced nature of valve design, manufacturing, quality inspection and other working methods, and thus ensure that valve parts are processed and assembled. the quality of. In addition, special processes such as welding, non-destructive testing and heat treatment of valve parts should be further optimized, and professional skills training and assessment should be carried out for relevant staff, and employees should be educated and trained on nuclear safety on a regular basis. Through the research and adoption of advanced process technology, nuclear power valve manufacturing enterprises have made the final quality of the valve meet the design standards and meet the requirements of relevant regulations.
references:
[1]ZHOU Yongliang. Analysis on Control Points of Valve Supervision Process in Nuclear Power Plants[J].Information Recording Materials,2017,18(11):29-30.
[2] Zheng Qingji, Ren Yongjuan. Practice and Suggestions on Supervision Work in Nuclear Power Valve Quality Control[J]. Mechanical Engineer, 2017(02): 141-142.
[3] Pan Feng, Li Wenmo. Practice of Valve Supervision in Conventional Island of Nuclear Power[J]. Equipment Supervision, 2015(01): 44-47.
[4] Zhou Guodong. Quality Control in the Process of Valve Manufacturing in Nuclear Power Projects [J]. Dual-use Technology and Products, 2017(18).
Key words: nuclear power plant; valve manufacturing; quality control introduction At present, there are many nuclear power plant valve manufacturers in China, but some manufacturers' valve quality control system is not perfect, and related enterprises lack nuclear safety awareness in the production process, and then make the production The valve cannot meet the needs of the nuclear power plant. In order to improve the manufacturing level and quality of nuclear power plant valves, relevant staff should strengthen the supervision of the valve manufacturing process, timely eliminate the defects and quality problems of valve products, and thus ensure the safety of nuclear power plants, and ultimately promote the development of China's nuclear power industry.
1 Introduction to Nuclear Power Plant Valves 1.1 Basic Characteristics of Nuclear Power Plant Valves Nuclear power plant valves are mainly installed on the pipelines of nuclear power equipment to control the flow of fluids in related equipment. Nuclear power plant valves have many functions, including interception, diversion, diversion, backflow prevention, pressure regulation, overflow relief, and regulation of flow. Nuclear power plant valves are an indispensable device in the daily operation of nuclear power plants and a reliable guarantee for the safe operation of nuclear power plants.
1.2 The basic structure of the valve The common nuclear power plant valves mainly have the following forms: gate valve, globe valve, ball valve, butterfly valve, diaphragm valve, check valve, regulating valve, safety valve and so on. These valves can play different roles depending on the installation method. The working environment of nuclear power plant valves is rather harsh. The types and temperatures of the valves passing through the valves are different. The nuclear power plants are radioactive, and the nuclear island valves should also have radiation resistance requirements.
1.3 Characteristics of Nuclear Power Plant Valves In the manufacture of nuclear power plant valves, relevant enterprises must first clarify the actual use of valves, because nuclear power plant valves are very different from those used in other occasions. Nuclear power plants have higher standards and requirements for valve quality. Therefore, relevant companies in the process of manufacturing valves, should try to configure ASME, RCC-M type of standard valves to ensure the safety index of the valve. The American Society of Mechanical Engineers (ASME) has set stricter standards for the manufacture of valves for nuclear power plant equipment and has assigned a corresponding level of safety. Among them, the number of diaphragm valves should account for 26.2% of the total number of nuclear power plant valves, the shut-off valve accounts for 33.6%, and the nuclear island valve accounts for 12.8%. At the same time, the number of valves meeting the safety index should not be less than 2.3%, and the total number of second- and third-stage valves should be It accounts for 52% of the total number of valves.
In addition to the intricate environment of the working conditions of the nuclear power plant valves, the radioactivity, temperature and pressure levels of the transport medium are also very demanding. The medium transported by the nuclear power plant valves is mainly saturated steam, condensed water, water vapor, primary circuit coolant, radiation corrosives, dilute sulfuric acid, lye and other media. There are four kinds of working conditions: normal, abnormal, emergency and accident. Common faults include internal leakage, external leakage and inoperability. If there is a problem with the quality of the nuclear power plant valve, failure to perform its safety function or directly cause a nuclear leak will seriously affect the safety of the nuclear power plant equipment, threatening the environment and people's health.
1.4 Localization of Nuclear Power Plant Valves In the past, China's nuclear power plants mainly used valves produced abroad, mainly because the design, test, manufacturing and quality inspection systems of imported nuclear power valves were relatively perfect, and the experience and technology of foreign manufacturers were relatively mature. In recent years, with the advancement of China's science and technology, domestically produced nuclear power valves have made great progress, but there are still insufficient design and research capabilities and insufficient testing capabilities, forging (die forging) and special high-end welding technology is not mature, manufacturing quality is not The status quo of stability and management system is not perfect. Therefore, the relevant state departments have put forward higher requirements for the quality control of the domestic nuclear power valve supervision process.
2 Nuclear power valve manufacturing control points analysis 2.1 Improve the technical standards and specifications of domestic nuclear power valves In order to further improve the quality and level of domestic nuclear power valve design, material selection, inspection and other aspects, the relevant national departments should quickly put the existing EJ, GB The relevant content of nuclear power valve manufacturing in technical standards and specifications is supplemented and improved according to the internationally advanced ASME and RCC-M standards, and the final standard is guaranteed to conform to China's actual national conditions and improve the operability of the valve manufacturing process. In this way, it is conducive to the domesticization of domestic nuclear power valves in all aspects of design, material selection and inspection.
2.2 Accelerate the realization of domestic nuclear power valve quality testing resource sharing By integrating the sharing of domestic nuclear power valve industry design, experiment, testing equipment and other resources, we can effectively avoid the repeated investment research of related enterprises, and accelerate the research process of China's nuclear power valve localization. In addition, domestic nuclear power valve laboratories and nuclear power valve testing and identification equipment should be managed by the state. All domestic nuclear power valve manufacturers can use these resources together, thus avoiding repeated investment in the same project, which not only saves the enterprise. Production costs can save the country a lot of manpower, material resources and financial resources.
2.3 Strengthening the quality control in the manufacturing process of nuclear power valves Nuclear power plants have very high requirements on the distribution and composition of chemical substances in valve forgings and castings. At the same time, there should be no obvious defects such as pores and slag inclusions on the surface of the valve body. In the quality control process of nuclear power valves, the staff should attach great importance to the wall thickness of forgings and castings, and do not allow negative deviations. At the same time, valve manufacturers should be required to provide complete non-destructive testing report or other quality of valve parts. certified documents. Valve supervisors also need to carefully check the quality of the valve raw materials, review the raw material quality certificate, and review the material grades and specifications used for the valve to ensure that the raw materials used meet the actual application requirements of the valve. When the valve supervisory personnel conduct supervision and management at the production site, it is necessary to check the appearance quality of the valve components. If the appearance quality is unqualified, it is necessary to carry out rectification in time.
The inspection management personnel must strictly review the non-destructive testing report to ensure that all non-destructive testing sites, testing methods, sampling rates, acceptance criteria, testing levels, testing personnel qualifications, and testing reports are in compliance with relevant technical agreements and design standards. Requirements; valves must undergo strict leak testing to ensure strength and tightness of the valve body. Due to the many influencing factors in the valve manufacturing process, it is inevitable that there will be cases that do not meet the requirements, standards or documentation requirements. When the nuclear power plant owner or the contractor carries out the valve acceptance inspection at the valve manufacturer, the non-conformance processing documents and non-conformities and deviation treatment reports shall be checked to ensure that the problem of the unqualified valves is finally resolved in the manufacturer.
2.4 Strengthening personnel training and technology introduction In order to effectively improve the design level and manufacturing quality of domestic nuclear power valves, relevant enterprises should strengthen the cultivation of professional talents and the introduction of advanced technologies. Domestic nuclear power valve manufacturers should pay attention to the manufacturing quality of nuclear power valves, increase investment in software and hardware in the production process, ensure the advanced nature of valve design, manufacturing, quality inspection and other working methods, and thus ensure that valve parts are processed and assembled. the quality of. In addition, special processes such as welding, non-destructive testing and heat treatment of valve parts should be further optimized, and professional skills training and assessment should be carried out for relevant staff, and employees should be educated and trained on nuclear safety on a regular basis. Through the research and adoption of advanced process technology, nuclear power valve manufacturing enterprises have made the final quality of the valve meet the design standards and meet the requirements of relevant regulations.
references:
[1]ZHOU Yongliang. Analysis on Control Points of Valve Supervision Process in Nuclear Power Plants[J].Information Recording Materials,2017,18(11):29-30.
[2] Zheng Qingji, Ren Yongjuan. Practice and Suggestions on Supervision Work in Nuclear Power Valve Quality Control[J]. Mechanical Engineer, 2017(02): 141-142.
[3] Pan Feng, Li Wenmo. Practice of Valve Supervision in Conventional Island of Nuclear Power[J]. Equipment Supervision, 2015(01): 44-47.
[4] Zhou Guodong. Quality Control in the Process of Valve Manufacturing in Nuclear Power Projects [J]. Dual-use Technology and Products, 2017(18).
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