A thermal management system for the thermal management of an external electric power generating nacelle equipping an electrically powered airship, the nacelle comprising electrical generation means implementing at least one turbogenerator contained in a fire containment vessel and provided with an air inlet duct for turbine feed air and a flue gas exhaust duct, this wherein the system comprises ventilation means for injecting external air into the fire containment vessel, and means for discharging ventilation air from the fire containment vessel, the said means for discharging the ventilation air surrounding the flue gas exhaust duct.