The Design And Research Of ADS Automatic Depressurization System Valve

With the steady growth of China’s demand for energy, nuclear power in our country has entered the booming development and technical upgrading and new stage. Is the key equipment of nuclear power plant and nuclear power valve equipment supporting products, its reliability will directly related to the safe operation of nuclear power plant, nuclear power equipment has become one of the focuses of the localization work on various aspects of focus and difficulty. For high pressure melt pile accident of AP1000 main loop set up four columns controlled automatic unloading system(ADS), of which three column pressure relief pipeline leads to the containment vessel refueling water storage tank, 1 column pressure relief pipeline leads to the containment atmosphere. Through redundancy and varied pressure relief measures, can reduce the circuit pressure reliably, thereby avoiding high-voltage fuse pile accident.ADS automatically step-down system valve is part of the reactor coolant system, and with the active reactor core cooling system(PXS) connection, is divided into four level step-down, its respectively connected to the reactor coolant system(RCS) of the three different positions. Level 1, 2 and 3 ADS automatically step-down system valve as stabilizer and pressure relief valve(PSARV) part of the module, connected to the voltage regulator at the top of the pipe mouth, the ADS automatically step-down system developed by the valve for level 2, ADS automatically step-down system are introduced the features of the valve, described the establishment of the numerical analysis model and its theoretical basis, the numerical simulation and theoretical calculation method for the analysis and comparison, through the numerical simulation method in view of the different valve opening selection and flow characteristics were analyzed, and get the equal pressure drop step mass flow and the curve of the valve opening, to achieve the control of the reactor coolant system step-down provide theoretical data. In the design process, according to ASME standards of classical mechanics compression part and important parts of the valve for structural strength to conduct stress analysis and strength calculation, the natural frequencies of the valve and for the analysis of seismic analysis and calculation of the equivalent static method, studies the characteristics of controlled buck slowly open the valve, the valve stem packing of floating close to study the sealing structure and principle, solve the valve controllable step-down and stem packing tightly sealed floating.