Abstract: Source term released into environment is the basis for accident power plant to determine appropriate emergency response level and protective action decision.Source term estimation based on power plant operating conditions is the most important emergency evaluation content during the emergency response period of nuclear power plant (NPP).Based on the relevant technical documents of IAEA and NRC,the procedures and basic data of accident release source term estimation based on pressurized water reactor (PWR) conditions were introduced,and seven practical accident release source term estimation methods were summarized.Based on these methods,a rapid release source term estimation program for PWR accident is developed.The program provides four release pathways for different estimation methods:containment leakage,containment bypass,steam generator tube rupture (SGTR) and direct environmental release.Reduction effect by decay,retention,spray and filtration etc.during release are considered in different release pathways except direct environmental release.The calculation results are close to that of RASCAL software released by Nuclear Regulatory Committee of United States.

Key words: source term, nuclear emergency, PWR, RASCAL