Emergency habitability system for main control room of AP1000 third generation nuclear power plant

Based on the important function of main control room emergency habitability system in the case of nuclear power design basis accident, analyses the system functions of AP1000 third generation nuclear power plant，and summarizes the basic design requirements for construction design, passive function realization and pressure boundary maintenance. Combined with the similar systems of other domestic plants, discusses the relationship between outdoor air supply, system layout design and effect of radiation protection, and analyses the influence of leakage classification on iodine protective factor according to ASME AG1.