[en] In order to prove fire safety of operating nuclear power plants, plant-specific fire hazard analysis should be performed. Furthermore the effect of design changes on fire safety should be reviewed periodically. At the estimating fire vulnerability stage, the factors that influence fire vulnerability include ignition sources, combustibles, fire barriers, fire protection features such as detection, alarm, suppression, evacuation are investigated. At the stage of fire hazard assessment, ignition and propagation hazard, passive and active fire protection features, and fire protection program such as pre-fire plan and related procedures are investigated. Based on the result of fire hazard analysis, reasonable improvement plan for fire protection can be established. This paper describes the result of fire hazard analysis classified by fire area for turbine building of which fire hazards and fire frequencies are relatively high in operating nuclear power plant