Improvement Analysis Of Seismic Structure Of Control Valves In Nuclear Power Plants

In the past 50 years, the basic function of the automatic control valve has not changed. It only improves on the fixed basic performance such as increasing flow coefficient, reducing noise, reducing cavitation and improving flow characteristics. However, the structural design characteristics change very slowly. Until the advent of nuclear energy, valve manufacturers were forced to consider the influence of external forces such as earthquakes when designing valves. This paper discusses the improvement of control valves from the point of view of seismic design; such as the selection of materials, the design of drive devices, the assembly of structures, and the assembly of parts.

      Control valves for nuclear power plants must be able to withstand the effects of earthquakes. In fact, this is the United States federal regulations stipulating the necessary conditions for a wide range of topics such as the design, construction, and operation of the country’s nuclear power plants. 10CFFR50 is the "United States Federal Equipment Production and Use License," and its Appendix A lists the "General Design Criteria for Nuclear Power Plants" (GDC). A paragraph in GDC-2 states: "Nuclear power station structures, devices and components must be designed to withstand the effects of natural phenomena such as earthquakes, tornadoes, hurricanes...". Other GDCs can also be used as a reference for indicating the necessary conditions for equipment anti-seismic and power restrictions. These include GDC-1, 4, 4, 14 and 30.

      Although nominally available, such generic standards that are not specified in detail cannot be implemented. As the nuclear industry matures, the anti-seismic design and analysis of nuclear power plant equipment will also be clarified. These GDCs proposed by all industrial sectors have a place in today's seismic design control valve improvements. The Nuclear Regulatory Commission (NRC) issued the "Standard Inspection Plan" and "Standard Regulation Guidelines." Various industrial organizations have also issued a series of regulations and standards called "NRC" requirements. Architectural designers and public utilities also began to issue relevant laws and regulations, and there are clear requirements for the application of standard adjustment guidelines, standard inspection programs and permits. At last. Control valve manufacturers have improved their product structure design to meet the industry's anti-seismic constraints.