Pressurizer control system( PCS) keeps safety rang of pressure of pressurized water reactor through sprayer and heater,which is safety critical system of nuclear power plant. According to the highly complex and non-linear characteristics of the dynamic thermal hydraulic process in PCS,this paper proposes to use STAMP model based system theory in safety analysis of PCSof AP1000 model,for the purpose of discovering the potential risks and strengthening its security constraints to prevent accident. It improves safety of nuclear power p...