The pressure stabilizer is important equipment to control the primary line pressure and make overpressure protection. Its main function covers: pressure control is to control the pressure variation within the specified scope in the course of system operation; water level regulation is to make up RCP system’s the change of water volume serving as the buffering tank for primary line coolant; Overpressure protection: involve in the startup of reactor and reactor shutdown regulation, that is, enable the step-up of RCP system when starting the reactor, and step-down of RCP system when stopping the reactor; it is attached with the function of degassing.