Abstract: An aircraft nacelle in which a power plant with an outside surface (46) is arranged, whereby the nacelle has an inside wall (44) that with the outside surface (46) of the power plant delimits a secondary annular pipe, at least one moving part (52) so as to create at least one lateral opening (54), and a thrust reversal device that has at least one moving physical obstacle (56, 58) that can occupy a first retracted state in which it does not deflect the stream that circulates in the secondary pipe and another deployed state in which it at least partially deflects the stream that circulates in the secondary annular pipe toward the at least one side opening (54), characterized in that it includes a ring (50) that is arranged in the secondary pipe, distant from the inside wall (44) of the nacelle and the outside surface (46) of the power plant that supports the at least one moving physical obstacle (56, 58).