The Research And Structure Analysis For Nuclear Class1 High Pressure Globe Valve

The Nuclear class1 high pressure globe valve is regarded as the important equipment of the reactor coolant system and auxiliary system(chemical volume control system). During normal operation, it is usually in a normally open state; Under emergency conditions, it plays a role of isolation in the system. The system is under the operation of high temperature, high pressure, severe working conditions, working medium is the reactor coolant which is inclusive of certain radioactive elements.For Example,the reactor coolant system which measures the temperature of the bypass adopt such Nuclear class1 high pressure globe valve, its application environment is very complex, which requires equipment to ensure the structural integrity in both open and closed state; On the other hand, when shutting down for maintenance, due to the medium with certain radioactive, the equipment need complete maintenance quickly.So the researching on rapid maintenance structure and its strength analysis for Nuclear class1 globe valve is very meaningful.At present, the domestic million kilowatt nuclear power units generally adopts screw cover lip welding structure, and this kind of structure has the advantages of a compact structure, a high strength shell and good reliability, but there are some disadvantages in terms of rapid maintenance: on the one hand, due to the lip's welding structure, disassembling process is complex, it is difficult to ensure complete online maintenance in a short time; on the other hand, it is hard to ensure that the valve's performance after the maintenance can reach the factory standard, because mounting conditions on site are not as good as the conditions in factory. To solve the problem of rapid maintenance, Velan valves produced RAMA series globe valve, which can achieve fast replacement parts within 15 minutes. It is a very good solution for the current domestic globe valves to overcome disassembly process complex &long time maintenance problems, at the same time it is also very good to ensure the valve's performance after maintenance. But it also exists some short comings such as a short service life of parts and need to be replaced periodically.This topic is based on the comparative analysis for the current domestic and international nuclear class I high pressure globe valve structure, fully considers the strength and reliability of nuclear valve and fast maintenance requirements, combined with the advantage and disadvantage of the valve at home and abroad, makes a new valve structure design. And the topic also establishes the valve three-dimensional structure model by solidworks software and completes theory strength calculation andANSYS finite element stress analysis for pressure boundary under working condition.Compared with the design input requirements, it determines the new valve structure not only meet the requirements of rapid maintenance, at the same time meet the requirements of nuclear grade valve with high reliability. The final result shows the valve structure in this paper comply with the design requirements.