Method for preventing overspeed trip of auxiliary feedwater steam-driven pump of nuclear power plant in full-flow test

The invention relates to the technical field of nuclear island systems, and provides a method for preventing overspeed trip of an auxiliary feedwater steam-driven pump of a nuclear power plant in a full-flow test. The feedwater steam-driven pump is used for supplying water to a steam generator and comprises a feedwater valve, a valve opening degree adjusting structure and a valve resetting control structure, wherein the valve resetting control structure is used for resetting the opening degree of the feedwater valve. The method comprises the steps that the valve opening degree adjusting structure is adjusted to set the opening degree of the feedwater valve to be 100%, so the feedwater valve can be automatically and fully opened after the feedwater steam-driven pump is started, and the opening degree of the water supply valve is 100% after the valve resetting control structure is started. After the feedwater steam-driven pump is started, the valve opening degree adjusting structure is adjusted so as to allow t