Anti-seismic Performance Evaluation And Optimum Design Of Nuclear Grade Main Feed-water Control Valve

With the rapid development of our national economy, urgent requirements have been putforward for China’s energy industry. At present, in order to ensure China’s energy security, optimizethe energy structure, support sustainable development of the national economy and other aspects ofurgent needs, China has formulated some polices, such as vigorously developing hydropower on thebasis of thermal power, and moderate development of new clean energy, for example, nuclearpower and wind power. China’s nuclear power construction is moving from trial, compensatoryadjustment to the development of strategic and aggressive. This is an excellent developmentopportunity for China’s nuclear power industry, and the huge demand of nuclear power plant valveshas brought a broad market prospect for domestic and foreign valve manufacturers.However, China ’s nuclear power valve industry started relatively late, after decades ofdevelopment, some achievements have been made, but compared to developed countries, the designand manufacture levels of China’s valve industry in the nuclear power equipment manufacturingindustry are still far behind developed countries, reliabilities and supporting capacities of varioustypes of valves still have large gaps with the international levels, especially in the valve design andproduction capacity. The class of the valve that independently producted in China is not high, thetechnology level is in the lower level. High technology content valves, such as main feed controlvalves, large diameter valve and so on, have not yet made a major breakthrough in the developmentand production, they have to be imported from abroad. To some extent, this increases our nuclearpower costs.On the basis of a large amount of domestic and foreign literature and books, with the routes of"theory research, product design, check, performance evaluation, and optimization”, the nuclearsecondary main feed water control valve was designed. First, some theoretical design calculationfor the nuclear power valve was carried out according to the ASME Nuclear Valve specificationstandards. Then, using the finite element software FEMAP, the seismic performances of thedesigned valve model were evalued, which include analysis of the natural vibration frequency of theoverall valve mode and strength analyses under four kinds of working conditions-normal,abnormal, emergency and accident cases, ensure that the loading conditions of the valve close toreality as far as possible, besides pressure produced by the medium of vavles model, it also includesthe force of pipe and valve stem on the valve. Next, according to the results of analysis, the pressureparts’ intensity were checked. Finally, according to the characteristics of the valve itself, optimizedthe brackets and above executive agencies which affect the frequency of valves. Then the valvemodel that meet the performance requirements and has optical size shape, was obtained.The innovation of this article is to explore a kind of simplified model according to the characteristics of the main feed water control valve itself, using the simplified model to analyzecomponents that affect the natural frequencies of vertical valves, getting the parameters affectingvalves’ first order frequency size and then optimizing the model.In this paper, the research work provides a more comprehensive approach for the seismicperformance evaluation of nuclear grade valve, provides a reference way to solve the problem ofvertical valves’ low frequency. It is significant for realizing the nuclear valve localization,improving working security and reliability and promoting ur nuclear industry’s merging into theworld.